Lagos Lagoon provides a number of important ecosystem services that include fish supply for the indigenous
fishing communities of Ilajes and Ijaws. The Lagoon is also a sink for pollutants from various point sources,
including sawmilling activities at the Okobaba hub of the lagoon. The perception of stakeholders about the
environmental risks of these anthropogenic activities is important considerations for sustainable management
of this important coastal ecosystem. Organic pollutants such as polycyclic aromatic hydrocarbons (PAHs)
are priority pollutants that are associated with anthropogenic activities including the burning of wastes. The
early life stages of fish species are useful bioindicators of pollutant effects for environmental risk assessments.
This study investigated stakeholders’ environmental risks perception of the sawmilling activities on the
Lagos Lagoon. Furthermore, physicochemical parameters and 16 priority PAHs were assessed in surface
water, porewater, and sediment from the study area on the Lagos Lagoon. Further, the embryotoxic effects
of crude and cleaned up sediment organics and porewater extracts on the African sharptooth catfish (Clarias
gariepinus) embryos were evaluated. Most (70–93%) respondents observed fish declines, burn wastes on
the bank of the lagoon and are aware of the environmental and human health risks of their activities. High
molecular weight PAHs dominated the PAHs profile, especially in the sediment. Developmental abnormalities
and decreased hatching success were observed in C. gariepinus embryos exposed to extracts from the test
site compared to the controls though non-significant (P > 0.05). The results show the environmental risks
of sawmill activities on the Lagos Lagoon. There is a need for targeted environmental management and
stakeholders’ engagement to forestall further coastal degradation and promote sustainable fisheries in the
lagoon in support of the UN sustainable development goal three (life below water).
This document discusses ways to reduce the ecological footprint of fish feed used in aquaculture. Currently, fish meal is a major protein source in fish feed due to its balanced nutrients. However, overfishing to meet demand for fish meal puts pressure on small pelagic fish populations. The document explores alternatives to fish meal such as terrestrial plant proteins, insects, terrestrial animal byproducts, and algae. These alternatives can help reduce the environmental impacts of aquaculture while still providing balanced nutrition to farmed fish. In conclusion, promoting omnivorous and herbivorous fish species that can eat plant-based diets, along with sustainable production of plant proteins, can help aquaculture be produced with less ecological impact.
The document provides information about careers in marine science and oceanography. It discusses what oceanography is, the different fields oceanographers work in such as physical, chemical, biological, and geological oceanography. It outlines some of the challenging questions oceanographers seek to answer. It also describes the types of jobs available to those with an oceanography education, including working for universities, government agencies, private companies, and international organizations. Finally, it discusses the necessary education path and courses needed to prepare for a career in oceanography.
Fluctuation of NO3-N and PO4 Elements in The Traditional Pond Area at TidesIJAEMSJORNAL
Traditional pond technology depends on nature in management, such as filling and disposal of pond water utilizing the time of low and high tides. The food for traditional pond technology comes from nature. The availability of nutrients such as N and P greatly determines the productivity of pond. The study was aimed to determine the fluctuations of N and P elements in traditional pond areas at tides. This research was conducted with purposive sampling method and laboratory analysis for several water parameters. The results showed that pH ranged from 7 to 8 both at low tide and high tide. The average value of nitrate (NO3) from five locations was extended from 0.106 to 1.495 mg/l. The value of silica (Si) ranged from 5,287 to 10,876 mg/l in low tide. Orthophosphate at low tide ranged from 0.027 to 0.090 mg/l, the highest value was in the coast station and the lowest was in the sea station. Whereas the value of nitrate (NO3) and orthophosphate in high tide ranged from 0.830 to 1.495 mg/l and 0.039 to 0.090 mg/l. Nutrients were abundant enough to support the growth and development of primary producers. So, the waters in this region include fertile waters.
FLORAL DIVERSITY OF MANGROVE ECOSYSTEM FROM COASTAL ENVIRONMENT OF URAN (RAIG...Prabhakar Pawar
Mangrove forests are among the world’s most productive ecosystems and are the only forests situated at the confluence of land and sea in tropical and subtropical latitudes.Mangroves are one of the biologically diverse ecosystems in the world, rich in organic matter and nutrients and support very large biomass of flora and fauna. With continuing degradation and destruction ofmangroves, there is a critical need to understand the biodiversity of the mangrove ecosystems.Mangroves represent spirit of Mumbai and NaviMumbai - they are plucky survivors. Each day, millions of citizens in Mumbai pass these hardy plants imaging they are little more than dirty, muddy weeds growing pointlessly along the shoreline. Overexploitation and unsustainable demand has resulted in considerable degradation of mangrove areas and it is feared that the area under mangroves around Mumbai areas has dwindled by 35% in the last 25 years and only about 20 Km2 of mangroves exist today. During this study, 4 species of true
mangroves representing 3 genera and 3 families, 10 species of mangrove associates belonging to 8 genera and 6 families and 1 species of non-mangrove halophytes were recorded from the mangrove ecosystems of Uran (Raigad), Navi Mumbai,Maharashtra.At present, coastal environment of Uran shows moderate mangrove density but in coming few years, area around Uran coast will be dominated by intense industrialization and urbanization. In such circumstances, pollution of Uran coast cannot be ignored. Therefore, data presented in this paper can be taken as a base line data for better management of these natural resources.
Key words: Mangroves diversity, Uran, Navi Mumbai,Maharashtra
Viability, method and device for horticultural crops with brackish and marine...Agriculture Journal IJOEAR
The method that humanity has adopted to hydrate and thus give life to the plants, imitating the model that was most visible, is the rain. However, the great secret to the contribution of nutrients to the vegetables, the irrigation itself, is on earth, in the groundwater layers and aquifers that hoard and administer the water, keeping every drop of rain and distributing the water through the basins, underground rivers, watering indirectly from the mountain to the sea. The key is in the different circulation velocities of the groundwater because of the nature of the substrates. However, agriculture has taken irrigation from above as we know it and has focused especially on drainage capacity. From this point of view, saline water is not beneficial for irrigated agriculture, but may be the only source of irrigation water in large arid regions, especially in developing countries, where the extreme scarcity of freshwater and the rapidly growing population require more water. When considering the possibility of watering with seawater without desalinating, always by means of capillarity systems, it is essential to take into consideration the different strata of soils, the distance to the groundwater, the composition of seawater, the capacity of drainage, chemical reactions of the soil with salts, etc. The modification of any of these parameters can produce effects of salinization, loss of humidity or desertification among others. This study presents the accumulated experience through the joint collaboration between the Centre for Research in Security and food Control of the Polytechnic University of Catalonia (CRESCA) and the Aqua Maris Foundation in capillary irrigation and it proposes a system and device that allows the controlled development of different vegetal species using brackish and seawater.
Coastal marine ecosystem scientific paper swissmitchick
The document summarizes a study assessing the macrobenthic flora and fauna in the intertidal area of Dalipuga Beach in Iligan City, Philippines. Two 1-square-meter quadrats were placed in the transect line to analyze species composition. Only one algae species (Phaeophyta) was found in the first quadrat, while the second quadrat contained both algae and seagrass. Water temperature was 26-27°C, soil temperature was 25-26°C, humidity was 26%, sediment was sand and gravel, and pH and salinity were normal. No macrobenthic fauna was found.
Physico-chemical parameters and macrobenthic invertebrates of the intertidal ...Angelo Mark Walag
Physico-chemical parameters and macrobenthic invertebrates of the intertidal zone of Gusa, Cagayan de Oro City, Philippines were assessed from March to May 2014. Water temperature, pH, salinity, dissolved oxygen, biological oxygen demand, and type of substrate were determined in the study were within the normal range. A modified transect-quadrat method was used in an approximately 14,000 m2 of study area. Seven hundred twenty seven individuals belonging to 15 species were found in the area. These organisms belong to four phyla namely: Mollusca, Arthropoda, Echinodermata, and Annelida. The three most abundant organisms found were Coenobita clypeatus, Ophiothrix longipeda, and Cypraea poraria with relative abundance of 73.86%, 4.13% and 3.71% respectively. Most of the macrobenthic fauna identified exhibited a clumped pattern of distribution, while the rest are randomly distributed. The species diversity of the area is 1.19 which is very low compared to reports from related studies.
Intact Oceans and Their Benefits, by Edward Lohnes, Conservation InternationalWILD Foundation
The document discusses several papers that illustrate the benefits of healthy oceans. It summarizes that intact oceans are crucial for life on Earth and provide many services like food and climate regulation. However, oceans face many threats from human activities. Studies show that marine protected areas can help restore ecosystems and biodiversity by limiting fishing and other extractive activities. Recent research also finds that dynamic protection approaches may further help increase fish biomass. Additionally, protecting blue carbon sinks can significantly offset carbon emissions and help mitigate climate change. Comprehensive ocean zoning is needed to manage cumulative human impacts on marine environments.
This document discusses ways to reduce the ecological footprint of fish feed used in aquaculture. Currently, fish meal is a major protein source in fish feed due to its balanced nutrients. However, overfishing to meet demand for fish meal puts pressure on small pelagic fish populations. The document explores alternatives to fish meal such as terrestrial plant proteins, insects, terrestrial animal byproducts, and algae. These alternatives can help reduce the environmental impacts of aquaculture while still providing balanced nutrition to farmed fish. In conclusion, promoting omnivorous and herbivorous fish species that can eat plant-based diets, along with sustainable production of plant proteins, can help aquaculture be produced with less ecological impact.
The document provides information about careers in marine science and oceanography. It discusses what oceanography is, the different fields oceanographers work in such as physical, chemical, biological, and geological oceanography. It outlines some of the challenging questions oceanographers seek to answer. It also describes the types of jobs available to those with an oceanography education, including working for universities, government agencies, private companies, and international organizations. Finally, it discusses the necessary education path and courses needed to prepare for a career in oceanography.
Fluctuation of NO3-N and PO4 Elements in The Traditional Pond Area at TidesIJAEMSJORNAL
Traditional pond technology depends on nature in management, such as filling and disposal of pond water utilizing the time of low and high tides. The food for traditional pond technology comes from nature. The availability of nutrients such as N and P greatly determines the productivity of pond. The study was aimed to determine the fluctuations of N and P elements in traditional pond areas at tides. This research was conducted with purposive sampling method and laboratory analysis for several water parameters. The results showed that pH ranged from 7 to 8 both at low tide and high tide. The average value of nitrate (NO3) from five locations was extended from 0.106 to 1.495 mg/l. The value of silica (Si) ranged from 5,287 to 10,876 mg/l in low tide. Orthophosphate at low tide ranged from 0.027 to 0.090 mg/l, the highest value was in the coast station and the lowest was in the sea station. Whereas the value of nitrate (NO3) and orthophosphate in high tide ranged from 0.830 to 1.495 mg/l and 0.039 to 0.090 mg/l. Nutrients were abundant enough to support the growth and development of primary producers. So, the waters in this region include fertile waters.
FLORAL DIVERSITY OF MANGROVE ECOSYSTEM FROM COASTAL ENVIRONMENT OF URAN (RAIG...Prabhakar Pawar
Mangrove forests are among the world’s most productive ecosystems and are the only forests situated at the confluence of land and sea in tropical and subtropical latitudes.Mangroves are one of the biologically diverse ecosystems in the world, rich in organic matter and nutrients and support very large biomass of flora and fauna. With continuing degradation and destruction ofmangroves, there is a critical need to understand the biodiversity of the mangrove ecosystems.Mangroves represent spirit of Mumbai and NaviMumbai - they are plucky survivors. Each day, millions of citizens in Mumbai pass these hardy plants imaging they are little more than dirty, muddy weeds growing pointlessly along the shoreline. Overexploitation and unsustainable demand has resulted in considerable degradation of mangrove areas and it is feared that the area under mangroves around Mumbai areas has dwindled by 35% in the last 25 years and only about 20 Km2 of mangroves exist today. During this study, 4 species of true
mangroves representing 3 genera and 3 families, 10 species of mangrove associates belonging to 8 genera and 6 families and 1 species of non-mangrove halophytes were recorded from the mangrove ecosystems of Uran (Raigad), Navi Mumbai,Maharashtra.At present, coastal environment of Uran shows moderate mangrove density but in coming few years, area around Uran coast will be dominated by intense industrialization and urbanization. In such circumstances, pollution of Uran coast cannot be ignored. Therefore, data presented in this paper can be taken as a base line data for better management of these natural resources.
Key words: Mangroves diversity, Uran, Navi Mumbai,Maharashtra
Viability, method and device for horticultural crops with brackish and marine...Agriculture Journal IJOEAR
The method that humanity has adopted to hydrate and thus give life to the plants, imitating the model that was most visible, is the rain. However, the great secret to the contribution of nutrients to the vegetables, the irrigation itself, is on earth, in the groundwater layers and aquifers that hoard and administer the water, keeping every drop of rain and distributing the water through the basins, underground rivers, watering indirectly from the mountain to the sea. The key is in the different circulation velocities of the groundwater because of the nature of the substrates. However, agriculture has taken irrigation from above as we know it and has focused especially on drainage capacity. From this point of view, saline water is not beneficial for irrigated agriculture, but may be the only source of irrigation water in large arid regions, especially in developing countries, where the extreme scarcity of freshwater and the rapidly growing population require more water. When considering the possibility of watering with seawater without desalinating, always by means of capillarity systems, it is essential to take into consideration the different strata of soils, the distance to the groundwater, the composition of seawater, the capacity of drainage, chemical reactions of the soil with salts, etc. The modification of any of these parameters can produce effects of salinization, loss of humidity or desertification among others. This study presents the accumulated experience through the joint collaboration between the Centre for Research in Security and food Control of the Polytechnic University of Catalonia (CRESCA) and the Aqua Maris Foundation in capillary irrigation and it proposes a system and device that allows the controlled development of different vegetal species using brackish and seawater.
Coastal marine ecosystem scientific paper swissmitchick
The document summarizes a study assessing the macrobenthic flora and fauna in the intertidal area of Dalipuga Beach in Iligan City, Philippines. Two 1-square-meter quadrats were placed in the transect line to analyze species composition. Only one algae species (Phaeophyta) was found in the first quadrat, while the second quadrat contained both algae and seagrass. Water temperature was 26-27°C, soil temperature was 25-26°C, humidity was 26%, sediment was sand and gravel, and pH and salinity were normal. No macrobenthic fauna was found.
Physico-chemical parameters and macrobenthic invertebrates of the intertidal ...Angelo Mark Walag
Physico-chemical parameters and macrobenthic invertebrates of the intertidal zone of Gusa, Cagayan de Oro City, Philippines were assessed from March to May 2014. Water temperature, pH, salinity, dissolved oxygen, biological oxygen demand, and type of substrate were determined in the study were within the normal range. A modified transect-quadrat method was used in an approximately 14,000 m2 of study area. Seven hundred twenty seven individuals belonging to 15 species were found in the area. These organisms belong to four phyla namely: Mollusca, Arthropoda, Echinodermata, and Annelida. The three most abundant organisms found were Coenobita clypeatus, Ophiothrix longipeda, and Cypraea poraria with relative abundance of 73.86%, 4.13% and 3.71% respectively. Most of the macrobenthic fauna identified exhibited a clumped pattern of distribution, while the rest are randomly distributed. The species diversity of the area is 1.19 which is very low compared to reports from related studies.
Intact Oceans and Their Benefits, by Edward Lohnes, Conservation InternationalWILD Foundation
The document discusses several papers that illustrate the benefits of healthy oceans. It summarizes that intact oceans are crucial for life on Earth and provide many services like food and climate regulation. However, oceans face many threats from human activities. Studies show that marine protected areas can help restore ecosystems and biodiversity by limiting fishing and other extractive activities. Recent research also finds that dynamic protection approaches may further help increase fish biomass. Additionally, protecting blue carbon sinks can significantly offset carbon emissions and help mitigate climate change. Comprehensive ocean zoning is needed to manage cumulative human impacts on marine environments.
IRJET- Hydrogeochemistry and Environmental Implication of Periyar River S...IRJET Journal
This document summarizes a study on the hydrogeochemistry and environmental implications of the Periyar River in southern Western Ghats, India after severe flooding in 2018. The study analyzed water and soil samples from different areas in the Periyar River basin to understand changes caused by the flood. Water samples were tested for various chemical parameters and compared to WHO and BIS standards. Soil samples were analyzed to determine Loss on Ignition (LOI) and composition through X-Ray Fluorescence (XRF). The results provide insight into the current water quality and soil composition/properties in the river basin following major flooding.
Determination of pH, Dissolved Oxygen, Sulphate, Phosphate and Total Hardness...Hanieh Farzaneh
Sampling of the Physico-chemical factors from two stations on the surface water of Kukkarahalli Lake in Mysore City-India was carried out biweekly over a period of 3 months of 2014. The aims were to determine some Physico chemical parameters of water pollution. Temperature was measured using mercury in glass thermometer. Dissolved oxygen was determined by modified Winkler azide method while Phosphate was determined by Vendo Molybdate Method, Estimation of Sulphate as Sulphur in sample by Nephelometric Method, measurements of total hardness by Complexometric Method. The result revealed that the major causes of water quality deterioration were related to excess usage of fertilizers and chemicals for increasing yield of the crop or releasing the sewage into the lake, due to cumulative effect of human activities where in sewage disposal oxygen is used in decomposing these organic water, eutrophication which causes algal bloom and therefore inability of oxygen to adequately dissolved in the water or the lentic nature of the site where was no serious upturns. As this Lake also used to be a source of water supply to the city of Mysore, and today is a house of different variety of birds, animals, plants and fishes it is very essential to stop sewage disposal and illegal excessive land encroachments to eliminate the eutropohication of the lake, which this results of the Physico-chemical examination of this lake could be helpful in the management of the lake for its water quality and fisheries.
This document is a glossary of fisheries terms published by NOAA Fisheries. It contains definitions of over 60 common fisheries-related terms starting with A, such as abundance, anadromous, aquaculture, assessment and associated species. The glossary provides concise explanations of technical terms to facilitate communication about fisheries science and management. It is intended to help the general public and professionals in other fields understand the language used by NOAA Fisheries in their work.
The document proposes transforming the unused ocean tank at Biosphere 2 into "The Desert Sea" - a living model of the Gulf of California highlighting the rich ecology and connection between the desert and sea. The Desert Sea would house diverse Gulf species and serve as a site for cutting-edge marine research while educating visitors. It describes plans to construct habitats like tidepools and a mangrove forest to build biological complexity. The project aims to understand how diversity develops and resilience to environmental change.
The document outlines a framework for scientific cooperation between South Africa and Brazil focused on the South and Tropical Atlantic Ocean and Southern Oceans. It describes the importance of these ocean regions for climate change, socioeconomic development, and biodiversity. However, they remain understudied compared to other oceans. The framework establishes areas of collaborative research including climate variability and change, ecosystems processes, and living and non-living resources. It aims to guide scientific cooperation between countries in the region to better understand and sustainably manage these important ocean basins.
Inorganic and methylmercury do they transfer along a tropical coastal food ...racheltrans
This study evaluated methylmercury (MeHg) and inorganic mercury (Hginorg) concentrations in water, plankton, and fish from Guanabara Bay, a eutrophic coastal area in Brazil. The aims were to compare the trophic transfer and biomagnification of MeHg and Hginorg between different trophic levels in the food web, from plankton to predatory fish. Water, microplankton, mesoplankton, and muscle tissue from 7 fish species with different feeding habits were sampled. Results showed that MeHg concentrations and proportions increased with trophic level, while Hginorg decreased, indicating MeHg was the species that biomagnified. MeHg also reflected the vertical
This document provides an overview of marine ecosystems. It discusses the key characteristics of marine ecosystems, including the abiotic (temperature, nutrients, salinity) and biotic (organisms, predators) components. It also describes several important marine habitats like oceans, estuaries, and on-shore ecosystems. Estuaries are productive areas where freshwater and saltwater mix that provide nurseries for many species. On-shore ecosystems like beaches, lagoons, and salt marshes experience tidal influences and land-sea interactions.
Ecological engineering in aquaculture use of seaweeds for removing nutrients ...Ivan Vera Montenegro
This document discusses using seaweeds as biofilters to remove dissolved nutrients from the effluent of intensive mariculture systems like fish farms and shrimp ponds. Two examples are provided where Gracilaria seaweed effectively removed 50-95% of dissolved ammonium released by fish in a tank system, and had up to 40% higher growth when cultivated near a fish cage farm, removing over 6% of the dissolved nitrogen released. Integrating seaweed cultivation with fish and shrimp farming can increase the nutrient assimilation capacity of an area and mitigate the environmental impacts of nutrient release, though more research is still needed.
Aquatic ecosystems are hot spots of most terrestrial biodiversity. They interact with their surrounding terrestrial area through food webs and habitat resources. The aquatic ecosystems also attract a wide range of other fauna including wading and migrating birds, amphibians, riparian mammals and insects. Furthermore, aquatic ecosystems have ability to recycle nutrients of wastewater. Despite many benefits they have, their potentiality in the rehabilitation of quarries is not well recognized. The recent effort on the rehabilitation of quarry site is mostly focused on terrestrial plants despite the fact that quarries life are heterogeneous ecosystems. Owing to this reason, there is a need of using the potential of aquatic ecosystems to enhance the rehabilitation of quarries sites. The present project is therefore focused on establishing the aquatic ecosystem at Wazo hill quarry.
The project won the 1st Prize in National Quarry Life Award in 2014 in Tanzania.
Read more: http://www.quarrylifeaward.com/project/potential-use-aquatic-ecosystems-enhancement-rehabilitation-mining-sites
The pelagic zone is the largest habitat on Earth, encompassing 330 million cubic miles of the open ocean. Within this zone, various species of pelagic fish and plankton are found throughout in numbers and distributions that vary depending on factors like light availability, nutrients, temperature, and pressure. The photic zone near the ocean's surface experiences a daily cycle of light and dark that is a powerful environmental signal, influencing diel vertical migrations of organisms seeking their optimum light intensity. Upwelling regions bring nutrients into surface waters, supporting highly productive marine ecosystems and fisheries. Plankton are primary producers and consumers that drift with ocean currents, and include phytoplankton like diatoms, dinoflagellates
This document discusses aquatic biodiversity and different marine and freshwater ecosystems. It describes the key producers, consumers, and larger organisms in aquatic environments. Some of the ecosystems highlighted include estuaries, mangrove forests, coral reefs, lakes, rivers, and wetlands. The document also notes threats to certain ecosystems like coral reefs and overfished areas.
This document summarizes a thesis submitted by Moumita Roy for a Master's degree in Environmental System Management. The thesis studied the state of the environment in and around Survey Park, Santosh Pur, Kolkata. Specifically, it analyzed various environmental parameters like climate, geology, groundwater, drainage, biodiversity, and water quality of ponds in the area. Water and air samples were collected and tested, and surveys were conducted to understand the environmental conditions and related issues in the study area. The results indicated issues with groundwater resources and pond water quality in the area. Overall, the study aimed to create awareness about environmental perspectives and promote sustainable management of resources in the study location.
2011 nutrient enrichment caused by marine cageearambulm3
This document summarizes a study that evaluated the influence of marine cage aquaculture on coral reef communities in turbid waters near Penghu Islands, Taiwan. The study found that levels of ammonium, nitrite, and chlorophyll a released from fish cages distinguished the area closest to the cages (Impact Zone 1) from areas further away (Impact Zone 2 and the reference zone). Coral communities closest to the cages were dominated by stress-tolerant coral species while areas further away supported more diverse coral morphologies. The results suggest that nutrient enrichment from the fish cages is deteriorating suitable habitat for coral reef organisms at the study site.
Environmental conditions and zooplankton community structure in five ponds in...Innspub Net
The degradation of surface water quality in Cameroon is linked to the absence of a functional waste management strategy. For such a strategy to be efficient, a general understanding of aquatic ecosystems will be of importance, these management strategies are particularly lacking in the eastern part of the country. To better understand and appreciate the ecosystems in the town of Bertoua, five ponds where chosen for the physicochemical and zooplankton communities analysis. Sampling on these ponds was conducted from March 2016 to April 2017 on a monthly basis. Samples for physicochemical analysis were collected at 20cm below water surface at the middle of each pond and measured were done following the recommendations of Rodier and Alpha. Biological samples were collected by filtering 50 liters of water through a 64µm mesh opening sieve. Identification was done using standard methods and identification keys. One-way ANOVA analysis was conducted to assess the potential differences between the different ponds base monthly observations. Although they are all hypereutrophic, with regard to the values of the physicochemical parameters, the five ponds showed no significant difference between them but, the structure of the zooplankton community remains very diverse. 118 zooplankton species have been identified in the five ponds. The distribution of zooplankton in these hydrosystems was mainly governed by the presence of organic matter. This study sheds light on the status and biological diversity of ponds in eastern Cameroon, data on which to rely to develop management strategies.
Science forum Day 2 - Suan Pheng Kam - Integrated aquculture planningWorldFish
The document summarizes a study on valuing the ecosystem services of wetlands in the Yellow River Delta in China. The study used stakeholder consultations, GIS mapping, and literature reviews to identify key ecosystem services provided by different wetland types. It then developed criteria to rate these services, and created maps showing the ratings for different land use types. The study found that while direct economic value is high, wetlands also provide important services like water purification, carbon storage, and biodiversity habitat. It provides recommendations on enhancing wetland management and promoting sustainable economic activities.
High scientific demand, sustainable management of sea
resources, assessment and monitoring of pollution sources and of
their environmental impact, urgency to understand how does the
biologic processes link to the Carbon cycle and how do they
impact climate: oceanic biologic parameters (primary production,
biomass, and pelagic populations) are in the depths of vital stakes
for our society sustainable development.
Today, Mercator-Ocean is strongly involved in producing
operational bulletins of the physical “blue” ocean. To use new
requirements, it is going to integrate the forecasting of the living
world seas’ component and become more “green”. A first quasireal
time demonstration phase will be launched in the beginning of
2006. LOBSTER biologic model will be integrated in the Mercator
operational chain. This new stage was made possible thanks to
the Bionuts research/operational collaboration. Five structures
contribute to this project: LEGOS (Toulouse), LEGI (Grenoble),
IPSL/OCEAN and IPSL/LSCE (Paris) and the GIP Mercator-
Ocean. In the News, Patrick Monfray & al. present us this project,
its stakes, as well as some recent results.
The three other Newsletter’s articles present an overview of the
Mercator associated research works on the “biology” thematic.
François Royer & al. are interested on the pelagic species’ spatial
dynamic, unavoidable stage for a better management of the sea
resources.
A toxic bloom of the cyanobacteria, Nodularia
spumigena has been reported in the Baltic Sea. On
July 24, 2003, SeaWiFS captured this view of the
blooming Baltic. (credits NASA)
In the scope of the Bionuts project, Leo Berline & al. have studied the assimilation impact (temperature, salinity, sea level)
on the biologic parameters of coupled biology/physical model. In fact, the confrontation of physical models to biology
constraints has revealed some negative effects of the assimilation scheme on the vertical processes performance. So,
improve them is a crucial stake for the biology/physical coupling.
At last, coupling between biologic and physical models is a great opportunity for Scientists to investigate how does the
dynamic impact the biology. Isabelle Dadou & al. have looked at the Rossby waves influence on the primary production.
Have a very good read!
This document summarizes a study on the state of the environment around Survey Park in Kolkata, India. It discusses the significance of urban ponds, increasing population pressures, and the need for proper pond management. It then describes the location of Survey Park and reasons for selecting it, which include its intimate relationship with three large ponds used by the local community. Water quality parameters were measured for the three ponds. The study methodology involved field surveys, sampling, and laboratory analysis. Flora, fauna, land use changes, soil types, climate, and groundwater in the area are also summarized.
Impacts from the Deepwater Horizon Oil Spill on Gulf of Mexico FisheriesChristine Hale
The document summarizes research on the impacts of the 2010 Deepwater Horizon oil spill on Gulf of Mexico fisheries. It discusses how the spill may have negatively affected individual fish through exposure to oil and dispersants, but that population- and community-level impacts have been less clear. It also notes several factors that influence the ability to determine the spill's effects, such as previous oil exposure in some areas, fishing closures during the spill, and the need for long-term studies.
1) The document discusses the ecological impact of sewage discharge on coral reefs. Sewage pollution introduces excess nutrients into coral reef ecosystems, which can cause eutrophication and algal overgrowth that damages corals.
2) A 3-year study found that doubling nutrient levels from sewage led to a doubling of coral bleaching events in Florida Keys reefs. Removing the nutrient pollution allowed for reef recovery.
3) About 96% of coral reef areas near human populations face sewage pollution problems. The majority of sewage in developing areas enters the ocean untreated. Even in developed nations, aging infrastructure can lead to sewage leaks that pollute coastal waters.
This presentation discuss about the human impact on ecosystem, planetary responses to changes and imbalance in the various ecological systems. The main cause of ecological change is the rapid increase in human population which ultimately utilize the non-renewable resources to fulfil their luxurious living standards and to discover various technologies to generate energy.
Evaluation of the Accumulation of Ethidium, Malathion, Trifluralin, Dichloro...BRNSSPublicationHubI
This study investigated the accumulation of 5 toxins - ethidium, malathion, trifluralin, DDT, and DDE - in the muscle tissue of 5 fish species from 3 areas of Anzali wetland in Iran. Gas chromatography was used to measure levels of the toxins. The study found that levels of DDT, DDE, ethidium and trifluralin did not differ significantly between the 3 areas. Ethidium and malathion levels were highest in fish and did not differ significantly. All 5 toxins were found to be below standards set by the World Health Organization, indicating they do not pose a health risk to consumers.
Laguna Lake Health Risk Assesment ACTA carcinogenic arsenic_released_feb2015Berean Guide
This document summarizes a study that assessed the carcinogenic health risks of arsenic in five commercially important fish species from Laguna de Bay in the Philippines. The study collected fish samples from eight sites around the lake during both dry and wet seasons. Arsenic levels were measured in the fish to determine if consumption poses health risks to humans. The goal was to understand both risks and benefits of eating these fish regularly from the lake to help inform public health recommendations.
IRJET- Hydrogeochemistry and Environmental Implication of Periyar River S...IRJET Journal
This document summarizes a study on the hydrogeochemistry and environmental implications of the Periyar River in southern Western Ghats, India after severe flooding in 2018. The study analyzed water and soil samples from different areas in the Periyar River basin to understand changes caused by the flood. Water samples were tested for various chemical parameters and compared to WHO and BIS standards. Soil samples were analyzed to determine Loss on Ignition (LOI) and composition through X-Ray Fluorescence (XRF). The results provide insight into the current water quality and soil composition/properties in the river basin following major flooding.
Determination of pH, Dissolved Oxygen, Sulphate, Phosphate and Total Hardness...Hanieh Farzaneh
Sampling of the Physico-chemical factors from two stations on the surface water of Kukkarahalli Lake in Mysore City-India was carried out biweekly over a period of 3 months of 2014. The aims were to determine some Physico chemical parameters of water pollution. Temperature was measured using mercury in glass thermometer. Dissolved oxygen was determined by modified Winkler azide method while Phosphate was determined by Vendo Molybdate Method, Estimation of Sulphate as Sulphur in sample by Nephelometric Method, measurements of total hardness by Complexometric Method. The result revealed that the major causes of water quality deterioration were related to excess usage of fertilizers and chemicals for increasing yield of the crop or releasing the sewage into the lake, due to cumulative effect of human activities where in sewage disposal oxygen is used in decomposing these organic water, eutrophication which causes algal bloom and therefore inability of oxygen to adequately dissolved in the water or the lentic nature of the site where was no serious upturns. As this Lake also used to be a source of water supply to the city of Mysore, and today is a house of different variety of birds, animals, plants and fishes it is very essential to stop sewage disposal and illegal excessive land encroachments to eliminate the eutropohication of the lake, which this results of the Physico-chemical examination of this lake could be helpful in the management of the lake for its water quality and fisheries.
This document is a glossary of fisheries terms published by NOAA Fisheries. It contains definitions of over 60 common fisheries-related terms starting with A, such as abundance, anadromous, aquaculture, assessment and associated species. The glossary provides concise explanations of technical terms to facilitate communication about fisheries science and management. It is intended to help the general public and professionals in other fields understand the language used by NOAA Fisheries in their work.
The document proposes transforming the unused ocean tank at Biosphere 2 into "The Desert Sea" - a living model of the Gulf of California highlighting the rich ecology and connection between the desert and sea. The Desert Sea would house diverse Gulf species and serve as a site for cutting-edge marine research while educating visitors. It describes plans to construct habitats like tidepools and a mangrove forest to build biological complexity. The project aims to understand how diversity develops and resilience to environmental change.
The document outlines a framework for scientific cooperation between South Africa and Brazil focused on the South and Tropical Atlantic Ocean and Southern Oceans. It describes the importance of these ocean regions for climate change, socioeconomic development, and biodiversity. However, they remain understudied compared to other oceans. The framework establishes areas of collaborative research including climate variability and change, ecosystems processes, and living and non-living resources. It aims to guide scientific cooperation between countries in the region to better understand and sustainably manage these important ocean basins.
Inorganic and methylmercury do they transfer along a tropical coastal food ...racheltrans
This study evaluated methylmercury (MeHg) and inorganic mercury (Hginorg) concentrations in water, plankton, and fish from Guanabara Bay, a eutrophic coastal area in Brazil. The aims were to compare the trophic transfer and biomagnification of MeHg and Hginorg between different trophic levels in the food web, from plankton to predatory fish. Water, microplankton, mesoplankton, and muscle tissue from 7 fish species with different feeding habits were sampled. Results showed that MeHg concentrations and proportions increased with trophic level, while Hginorg decreased, indicating MeHg was the species that biomagnified. MeHg also reflected the vertical
This document provides an overview of marine ecosystems. It discusses the key characteristics of marine ecosystems, including the abiotic (temperature, nutrients, salinity) and biotic (organisms, predators) components. It also describes several important marine habitats like oceans, estuaries, and on-shore ecosystems. Estuaries are productive areas where freshwater and saltwater mix that provide nurseries for many species. On-shore ecosystems like beaches, lagoons, and salt marshes experience tidal influences and land-sea interactions.
Ecological engineering in aquaculture use of seaweeds for removing nutrients ...Ivan Vera Montenegro
This document discusses using seaweeds as biofilters to remove dissolved nutrients from the effluent of intensive mariculture systems like fish farms and shrimp ponds. Two examples are provided where Gracilaria seaweed effectively removed 50-95% of dissolved ammonium released by fish in a tank system, and had up to 40% higher growth when cultivated near a fish cage farm, removing over 6% of the dissolved nitrogen released. Integrating seaweed cultivation with fish and shrimp farming can increase the nutrient assimilation capacity of an area and mitigate the environmental impacts of nutrient release, though more research is still needed.
Aquatic ecosystems are hot spots of most terrestrial biodiversity. They interact with their surrounding terrestrial area through food webs and habitat resources. The aquatic ecosystems also attract a wide range of other fauna including wading and migrating birds, amphibians, riparian mammals and insects. Furthermore, aquatic ecosystems have ability to recycle nutrients of wastewater. Despite many benefits they have, their potentiality in the rehabilitation of quarries is not well recognized. The recent effort on the rehabilitation of quarry site is mostly focused on terrestrial plants despite the fact that quarries life are heterogeneous ecosystems. Owing to this reason, there is a need of using the potential of aquatic ecosystems to enhance the rehabilitation of quarries sites. The present project is therefore focused on establishing the aquatic ecosystem at Wazo hill quarry.
The project won the 1st Prize in National Quarry Life Award in 2014 in Tanzania.
Read more: http://www.quarrylifeaward.com/project/potential-use-aquatic-ecosystems-enhancement-rehabilitation-mining-sites
The pelagic zone is the largest habitat on Earth, encompassing 330 million cubic miles of the open ocean. Within this zone, various species of pelagic fish and plankton are found throughout in numbers and distributions that vary depending on factors like light availability, nutrients, temperature, and pressure. The photic zone near the ocean's surface experiences a daily cycle of light and dark that is a powerful environmental signal, influencing diel vertical migrations of organisms seeking their optimum light intensity. Upwelling regions bring nutrients into surface waters, supporting highly productive marine ecosystems and fisheries. Plankton are primary producers and consumers that drift with ocean currents, and include phytoplankton like diatoms, dinoflagellates
This document discusses aquatic biodiversity and different marine and freshwater ecosystems. It describes the key producers, consumers, and larger organisms in aquatic environments. Some of the ecosystems highlighted include estuaries, mangrove forests, coral reefs, lakes, rivers, and wetlands. The document also notes threats to certain ecosystems like coral reefs and overfished areas.
This document summarizes a thesis submitted by Moumita Roy for a Master's degree in Environmental System Management. The thesis studied the state of the environment in and around Survey Park, Santosh Pur, Kolkata. Specifically, it analyzed various environmental parameters like climate, geology, groundwater, drainage, biodiversity, and water quality of ponds in the area. Water and air samples were collected and tested, and surveys were conducted to understand the environmental conditions and related issues in the study area. The results indicated issues with groundwater resources and pond water quality in the area. Overall, the study aimed to create awareness about environmental perspectives and promote sustainable management of resources in the study location.
2011 nutrient enrichment caused by marine cageearambulm3
This document summarizes a study that evaluated the influence of marine cage aquaculture on coral reef communities in turbid waters near Penghu Islands, Taiwan. The study found that levels of ammonium, nitrite, and chlorophyll a released from fish cages distinguished the area closest to the cages (Impact Zone 1) from areas further away (Impact Zone 2 and the reference zone). Coral communities closest to the cages were dominated by stress-tolerant coral species while areas further away supported more diverse coral morphologies. The results suggest that nutrient enrichment from the fish cages is deteriorating suitable habitat for coral reef organisms at the study site.
Environmental conditions and zooplankton community structure in five ponds in...Innspub Net
The degradation of surface water quality in Cameroon is linked to the absence of a functional waste management strategy. For such a strategy to be efficient, a general understanding of aquatic ecosystems will be of importance, these management strategies are particularly lacking in the eastern part of the country. To better understand and appreciate the ecosystems in the town of Bertoua, five ponds where chosen for the physicochemical and zooplankton communities analysis. Sampling on these ponds was conducted from March 2016 to April 2017 on a monthly basis. Samples for physicochemical analysis were collected at 20cm below water surface at the middle of each pond and measured were done following the recommendations of Rodier and Alpha. Biological samples were collected by filtering 50 liters of water through a 64µm mesh opening sieve. Identification was done using standard methods and identification keys. One-way ANOVA analysis was conducted to assess the potential differences between the different ponds base monthly observations. Although they are all hypereutrophic, with regard to the values of the physicochemical parameters, the five ponds showed no significant difference between them but, the structure of the zooplankton community remains very diverse. 118 zooplankton species have been identified in the five ponds. The distribution of zooplankton in these hydrosystems was mainly governed by the presence of organic matter. This study sheds light on the status and biological diversity of ponds in eastern Cameroon, data on which to rely to develop management strategies.
Science forum Day 2 - Suan Pheng Kam - Integrated aquculture planningWorldFish
The document summarizes a study on valuing the ecosystem services of wetlands in the Yellow River Delta in China. The study used stakeholder consultations, GIS mapping, and literature reviews to identify key ecosystem services provided by different wetland types. It then developed criteria to rate these services, and created maps showing the ratings for different land use types. The study found that while direct economic value is high, wetlands also provide important services like water purification, carbon storage, and biodiversity habitat. It provides recommendations on enhancing wetland management and promoting sustainable economic activities.
High scientific demand, sustainable management of sea
resources, assessment and monitoring of pollution sources and of
their environmental impact, urgency to understand how does the
biologic processes link to the Carbon cycle and how do they
impact climate: oceanic biologic parameters (primary production,
biomass, and pelagic populations) are in the depths of vital stakes
for our society sustainable development.
Today, Mercator-Ocean is strongly involved in producing
operational bulletins of the physical “blue” ocean. To use new
requirements, it is going to integrate the forecasting of the living
world seas’ component and become more “green”. A first quasireal
time demonstration phase will be launched in the beginning of
2006. LOBSTER biologic model will be integrated in the Mercator
operational chain. This new stage was made possible thanks to
the Bionuts research/operational collaboration. Five structures
contribute to this project: LEGOS (Toulouse), LEGI (Grenoble),
IPSL/OCEAN and IPSL/LSCE (Paris) and the GIP Mercator-
Ocean. In the News, Patrick Monfray & al. present us this project,
its stakes, as well as some recent results.
The three other Newsletter’s articles present an overview of the
Mercator associated research works on the “biology” thematic.
François Royer & al. are interested on the pelagic species’ spatial
dynamic, unavoidable stage for a better management of the sea
resources.
A toxic bloom of the cyanobacteria, Nodularia
spumigena has been reported in the Baltic Sea. On
July 24, 2003, SeaWiFS captured this view of the
blooming Baltic. (credits NASA)
In the scope of the Bionuts project, Leo Berline & al. have studied the assimilation impact (temperature, salinity, sea level)
on the biologic parameters of coupled biology/physical model. In fact, the confrontation of physical models to biology
constraints has revealed some negative effects of the assimilation scheme on the vertical processes performance. So,
improve them is a crucial stake for the biology/physical coupling.
At last, coupling between biologic and physical models is a great opportunity for Scientists to investigate how does the
dynamic impact the biology. Isabelle Dadou & al. have looked at the Rossby waves influence on the primary production.
Have a very good read!
This document summarizes a study on the state of the environment around Survey Park in Kolkata, India. It discusses the significance of urban ponds, increasing population pressures, and the need for proper pond management. It then describes the location of Survey Park and reasons for selecting it, which include its intimate relationship with three large ponds used by the local community. Water quality parameters were measured for the three ponds. The study methodology involved field surveys, sampling, and laboratory analysis. Flora, fauna, land use changes, soil types, climate, and groundwater in the area are also summarized.
Impacts from the Deepwater Horizon Oil Spill on Gulf of Mexico FisheriesChristine Hale
The document summarizes research on the impacts of the 2010 Deepwater Horizon oil spill on Gulf of Mexico fisheries. It discusses how the spill may have negatively affected individual fish through exposure to oil and dispersants, but that population- and community-level impacts have been less clear. It also notes several factors that influence the ability to determine the spill's effects, such as previous oil exposure in some areas, fishing closures during the spill, and the need for long-term studies.
1) The document discusses the ecological impact of sewage discharge on coral reefs. Sewage pollution introduces excess nutrients into coral reef ecosystems, which can cause eutrophication and algal overgrowth that damages corals.
2) A 3-year study found that doubling nutrient levels from sewage led to a doubling of coral bleaching events in Florida Keys reefs. Removing the nutrient pollution allowed for reef recovery.
3) About 96% of coral reef areas near human populations face sewage pollution problems. The majority of sewage in developing areas enters the ocean untreated. Even in developed nations, aging infrastructure can lead to sewage leaks that pollute coastal waters.
This presentation discuss about the human impact on ecosystem, planetary responses to changes and imbalance in the various ecological systems. The main cause of ecological change is the rapid increase in human population which ultimately utilize the non-renewable resources to fulfil their luxurious living standards and to discover various technologies to generate energy.
Similar to Stakeholders’ Perception of Fish Decline in the Lagos Lagoon and Effects of Sawmilling Activities on Water Quality and Clarias gariepinus Embryos
Evaluation of the Accumulation of Ethidium, Malathion, Trifluralin, Dichloro...BRNSSPublicationHubI
This study investigated the accumulation of 5 toxins - ethidium, malathion, trifluralin, DDT, and DDE - in the muscle tissue of 5 fish species from 3 areas of Anzali wetland in Iran. Gas chromatography was used to measure levels of the toxins. The study found that levels of DDT, DDE, ethidium and trifluralin did not differ significantly between the 3 areas. Ethidium and malathion levels were highest in fish and did not differ significantly. All 5 toxins were found to be below standards set by the World Health Organization, indicating they do not pose a health risk to consumers.
Laguna Lake Health Risk Assesment ACTA carcinogenic arsenic_released_feb2015Berean Guide
This document summarizes a study that assessed the carcinogenic health risks of arsenic in five commercially important fish species from Laguna de Bay in the Philippines. The study collected fish samples from eight sites around the lake during both dry and wet seasons. Arsenic levels were measured in the fish to determine if consumption poses health risks to humans. The goal was to understand both risks and benefits of eating these fish regularly from the lake to help inform public health recommendations.
Status of Phytoplankton Community of Kisumu Bay, Winam Gulf, Lake Victoria, K...theijes
Lake Victoria has undergone remarkable and diverse ecological perturbations which are as a result of physical, chemical and biological processes, together with human activities that take place in the watershed area and within the lake itself. The most observed effects include increases in phytoplankton biomass and frequent algal blooms. In this study species composition, abundance, spatial and temporal distribution of phytoplankton as well as total phytoplankton biomass of Kisumu Bay, (Winam Gulf), Lake Victoria, Kenya was studied for six months in the wake of climate change. Sampling was done every two weeks using a Van Dorn Water sampler to take water samples and algal cells were counted under an inverted microscope with the help of a Sedge-Wick Rafter Cell in order to determine density. Phytoplankton biomass indicated by chlorophyll-content was determined through cold extraction in acetone and subsequent quantification by spectrophotometry. Physicochemical parameters were measured in situ using respective meters, while plant nutrient levels were determined by spectrophotometric methods following standard methods of APHA 1985 and Gems (1992) Handbook. ANOVA test was used to determine any temporal and spatial variability in the biological factors. Regression and Pearson’s correlation analyses were done to establish relationships between these factors. LSD test was done to determine means which were significantly different. The results indicated that a total of 36 genera of algae belonging to Cyanophyta, Bacillariophyta, Chlorophyta and Pyrrophyta were present, with dominance of the classes in terms of number of species being in that order. Chroococcus species was the most abundant and its density was significantly different from all the others. Most algal species were more or less homogenously distributed in the bay (p=1.0000) and over the study period (p=1.0000), but their densities varied significantly between different species (p<0.0001). From these results, it can be concluded that the phytoplankton community within the bay is becoming very dynamic and could possibly portray the status in the whole lake. Diatoms are becoming increasingly dominant. There is continual increasing trend in physico-chemical factors. The information obtained from this work contributes to the understanding of ecological changes in the bay in response to climate change and variability and thus the threat to biodiversity. This information is therefore important for ecological and management purposes of the lake and understanding effects of climate change on ecosystem structure, functioning and productivity.
Established the Environmental Monitoring Program Indicators to Prevent Diseas...CrimsonpublishersCJMI
Established the Environmental Monitoring Program Indicators to Prevent Disease Infection and Promote Sustainable Development by Yi-Che Shih in Cohesive Journal of Microbiology & Infectious Disease
Diversity and abundance of Macrobenthos in a subtropical estuary, BangladeshAbdullaAlAsif1
Soft bottom macrobenthos are important component of the marine and coastal trophic chain. There has been sparse information regarding the distribution of soft bottom macrobenthos form the coastal water of Bangladesh. Consequently, the present study was an effort to reveal the diversity and abundance of macrobenthos in the Feni Estuary in a seasonal pattern together with the hydrological factors. A total of 17 taxa families of soft-bottom invertebrates were found over the two sampling seasons. The current study yielded a total number of 34,726 ind./m 2 (mean 2480ind./m 2) including 18,909ind./m 2 in wet season (mean 2682ind./m 2) and 15,817 ind./m 2 in dry season (2259ind./m 2). The highest density of soft-bottom invertebrates was in the wet season while the lowest number in the dry season. A total of 5 groups of macrobenthos were found over the two sampling seasons. The dominant group was Polychaeta that contributed 43.60% of the total soft-bottom invertebrates. The values of biodiversity indices were higher in dry season compare to the wet season in most of the sampling station during the study period.
Mangroves are vital for healthy coastal ecosystems in many regions of the world and research and studies are revealing the unique importance of these habitats to the planet. The Mangrove Action Project is dedicated to reversing the degradation and loss of mangrove forest wetlands and their associated coastal ecosystems worldwide. www.mangroveactionproject.org
1) The document evaluates the management effectiveness of the National Natural Park Rosario and San Bernardo Corals marine protected area in Colombia using biological, socioeconomic, and governance indicators.
2) Biological surveys found low coral cover and fish diversity/abundance both inside and outside the MPA, suggesting limited effectiveness of current management. The reefs also showed signs of degradation.
3) Socioeconomic and governance analyses revealed low incomes for local communities, few opportunities, weak governance, and overexploitation of resources inside the MPA. This reflected low adaptive capacity to comply with conservation rules.
Factors Contributing to the Decline of the Anchovy Fisheries in Krueng Raya B...Zulhamsyah Imran
This document summarizes a study on factors contributing to the decline of anchovy fisheries in Krueng Raya Bay, Indonesia. The study found that anchovy production peaked at 2,072 tons in 1999 but declined sharply to 171 tons after the 2004 tsunami. While production fluctuated between 126-279 tons from 2006-2012, it remained well below pre-tsunami and predicted maximum sustainable yield levels. The decline is attributed to increasing fishing effort through more lift net boats, destructive fishing gears, and degradation of coral reefs and mangroves from pollution and other human impacts. The tsunami exacerbated the decline but other anthropogenic factors likely had a greater long-term impact on depleting the anchovy stocks.
The Institute for Applied Ecology New Zealand (AENZ) is based at AUT University and conducts internationally significant research in applied ecology. AENZ's research focuses on conservation, human-environment interactions, marine ecology and aquaculture, and plant ecology and global change. It provides research and consultancy services, using facilities like aerial drones, analytical chemistry labs, and marine vessels. Past successful projects include studies on a new surf clam fishery, microbial recovery in Mars analogue soils, and pest eradication on seabird islands.
Adaptive mechanisms of rural fishermen towards climate change on quantity of ...Alexander Decker
This document summarizes a study that investigated the adaptive mechanisms of rural fishermen towards climate change in Asari-Toru Local Government Area of Rivers State, Nigeria. The study found that fishermen employed building sea walls, diversifying to off-farm activities, and restoring mangroves to adapt to climate impacts like flooding, sea level rise, and changes in fish populations. Using an analysis of costs and revenues, the study determined that these adaptation mechanisms improved fishermen's productivity and profitability, with a net profit of N500,455.1 reported. However, the major problem identified was the high cost of fishing materials.
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Ecosystem Services and Perception of Water Quality of Lake Barombi Kotto, Cam...ijtsrd
This study carried out in BarombiKotto was aimed at assessing ecosystem services provided by Lake BarombiKotto and its riparian vegetation and to determine the level of awareness of this community to threats to degradation of water quality and riparian vegetation. Two hundred semi structured questionnaires were administered to the inhabitants of BarombiKotto village using the purposive sampling method. The Likert rating method was used to derive quantitative data that was further analysed using SPSS version 17. Results revealed that, respondents depended on the lake and vegetation for the provision of water for drinking, domestic purposes, irrigation, transport, recreational and cultural activities and also on forest benefits like wood for fuel, construction and medicinal plants. Significant associations were found between age group, level of education and respondentsawareness about the threats to water quality and sustainable practices. Agriculture, harvest of wood for construction, high fishing rates, increasing abundance of aquatic weeds were identified as major threats to Lake BarombiKotto and its surrounding vegetation. Water quality attributes like reduced transparency, lake depth, and other parameters such as aquatic weeds and fish stocks have changed in Lake BarombiKotto. The absence of conventional waste management facilities in BarombiKotto community and poor sanitary conditions of toilets could be responsible for the contamination of this lake and hence the high prevalence of typhoid, dysentery and other gastrointestinal infections among respondents. Awo Miranda Egbe | Beatrice Ambo Fonge | Pascal Tabi Tabot ""Ecosystem Services and Perception of Water Quality of Lake Barombi Kotto, Cameroon"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-3 , April 2019, URL: https://www.ijtsrd.com/papers/ijtsrd23529.pdf
Paper URL: https://www.ijtsrd.com/biological-science/ecology/23529/ecosystem-services-and-perception-of-water-quality-of-lake-barombi-kotto-cameroon/awo-miranda-egbe
Ecosystem Services and Perception of Water Quality of Lake Barombi Kotto, Cam...ijtsrd
This study carried out in BarombiKotto was aimed at assessing ecosystem services provided by Lake BarombiKotto and its riparian vegetation and to determine the level of awareness of this community to threats to degradation of water quality and riparian vegetation. Two hundred semi structured questionnaires were administered to the inhabitants of BarombiKotto village using the purposive sampling method. The Likert rating method was used to derive quantitative data that was further analysed using SPSS version 17. Results revealed that, respondents depended on the lake and vegetation for the provision of water for drinking, domestic purposes, irrigation, transport, recreational and cultural activities and also on forest benefits like wood for fuel, construction and medicinal plants. Significant associations were found between age group, level of education and respondentsawareness about the threats to water quality and sustainable practices. Agriculture, harvest of wood for construction, high fishing rates, increasing abundance of aquatic weeds were identified as major threats to Lake BarombiKotto and its surrounding vegetation. Water quality attributes like reduced transparency, lake depth, and other parameters such as aquatic weeds and fish stocks have changed in Lake BarombiKotto. The absence of conventional waste management facilities in BarombiKotto community and poor sanitary conditions of toilets could be responsible for the contamination of this lake and hence the high prevalence of typhoid, dysentery and other gastrointestinal infections among respondents. Awo Miranda Egbe | Beatrice Ambo Fonge | Pascal Tabi Tabot ""Ecosystem Services and Perception of Water Quality of Lake Barombi Kotto, Cameroon"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-3 , April 2019, URL: https://www.ijtsrd.com/papers/ijtsrd23529.pdf
Paper URL: https://www.ijtsrd.com/biological-science/ecology/23529/ecosystem-services-and-perception-of-water-quality-of-lake-barombi-kotto-cameroon/awo-miranda-egbe
AQUATIC GENETIC RESOURCES AND CLIMATE CHANGE_CleanPatrick White
This document provides an overview of the importance of aquatic genetic resources in the context of climate change. It discusses how aquatic ecosystems and the organisms they support play a key role in global carbon and nutrient cycles. Aquatic genetic resources underpin global aquaculture and fisheries, which together provide about half of the world's food fish and are important for food security, nutrition, and livelihoods. Climate change poses challenges for these resources and the sectors that depend on them through impacts like warming, acidification, and changes to freshwater availability. The roles of aquatic genetic resources in adapting to and mitigating climate change impacts are discussed.
DOI: 10.21276/ijlssr.2016.2.4.10
bio-indicators. The present study is focused on the effective use of L. rohita, an economically significant carp as a
bio-indicator of zinc pollution through its several physiological, histopathological biomarkers. Primarily, acute toxicity
test is performed in which the carp fingerlings are exposed to different concentrations (10, 20, 40, 80, 160, 320 ppm) of
zinc sulphate. 96 hour LC50 value is determined to be 100 ppm. It is taken as lethal concentration and the fishes are
exposed to it for a period of 96 hours during which wide range of behavioural abnormalities are evidenced like general
hyperactivity, surfacing activity, hyper-opercular activity, and erratic swimming pattern. It is followed by loss of balance
and convolutions. One fifth of the lethal concentration is taken (i.e., 10 ppm) as sub-lethal concentration and fishes are
exposed to it for a period of 15 days during which growth, behaviour, oxygen consumption, histopathology, hematology
and genotoxicity are studied. Negative growth performance is observed with insignificant length increment up to 0.24 %
and significant weight reduction up to -2.38 %. Wide range of behavioural abnormalities are evidenced which includes,
erratic swimming, hyperactivity, surfacing activity and depression in appetite. Besides, general body discolouration and
haemorrhage are observed as well. Rate of oxygen consumption showed a time dependant decrease which ranged up to
-49.10%. Gills of the fishes are shown to have conspicuous histopathological alterations like lamellar necrosis, lamellar
fusion, lamellar erosion, epithelial lifting and epithelial swelling. Key-words- Bioindicator, L. rohita, Zinc sulphate, Growth, Behaviour, Oxygen Consumption, Histopathology
Lindane and Endosulfan Sulfate Isomers in Crassostrea virginica (Gmelin, 1791...IJEAB
This document summarizes a study that analyzed concentrations of lindane and endosulfan sulfate isomers in oyster (Crassostrea virginica) populations in two lagoon systems in the central Gulf of Mexico. Samples were collected from four oyster banks in the Mandinga lagoon system and analyzed using gas chromatography. Results showed mean lindane concentrations of 8.69 ng/g and endosulfan sulfate concentrations up to 24.68 ng/g in oysters from Mandinga. Lower mean concentrations of 4.11 ng/g for lindane and up to 11.38 ng/g for endosulfan sulfate were found in the Alvarado lagoon
The document discusses an initiative between two schools in Hong Kong, South Island School and West Island School, called SWIMS. The initiative aims to establish permanent reef survey areas to collect long-term data on the health of Hong Kong's coral reef ecosystem through staff and student training and collaboration. It will provide experiences for students' careers and curriculum like CAS, IB, and environmental studies. The status of global coral reefs is also discussed, noting they cover less than 1% of the ocean but support 25% of marine species and are threatened by climate change, overfishing, and acidification. The Reef Check program is introduced as combining education, science, and conservation through volunteer reef monitoring teams in over 80 countries to assess and
Catch Per Unit Effort (CPUE) of Bivalves in Northwestern Bohol, PhilippinesAI Publications
Catch Per Unit Effort (CPUE) is a measure of status of marine resource in a given area. In this study, bivalve fishery information was gathered using the self-structured questionnaire. There were 61 respondents who were the registered fishermen of Calape, Tubigon and Clarin. Among the three towns it was Clarin where highest mean CPUE was observed with 1.2kg/hr/man. This was followed by Calape with 0.8kg/hr/man and lowest mean CPUE was recorded in Tubigon with 0.6kg/hr/man. High CPUE value means that there are still enough bivalve resources in the area and lowest CPUE means that these resources are endangered. Considering that, the result of this study showed that there is a need to regulate the collection of bivalves with lower wild stocks to avoid loss of these natural resources.
Introduction to the ecosystem approach as a framework for management of ecosy...Iwl Pcu
7th GEF Biennial International Waters Conference in Barbados Presentation on ecosystem approach as a framework for management of ecosystem use by Rhodes University
Similar to Stakeholders’ Perception of Fish Decline in the Lagos Lagoon and Effects of Sawmilling Activities on Water Quality and Clarias gariepinus Embryos (20)
ALPHA LOGARITHM TRANSFORMED SEMI LOGISTIC DISTRIBUTION USING MAXIMUM LIKELIH...BRNSS Publication Hub
The document discusses the alpha logarithm transformed semi-logistic distribution and its maximum likelihood estimation method. It introduces the distribution, provides its probability density function and cumulative distribution function. It then describes generating random numbers from the distribution and outlines the maximum likelihood estimation method to estimate the distribution's unknown parameters. This involves deriving the likelihood function and taking its partial derivatives to obtain equations that are set to zero and solved to find maximum likelihood estimates of the location, scale, and shape parameters.
AN ASSESSMENT ON THE SPLIT AND NON-SPLIT DOMINATION NUMBER OF TENEMENT GRAPHSBRNSS Publication Hub
This document summarizes research on the split and non-split domination numbers of tenement graphs. It defines tenement graphs and provides basic definitions of domination, split domination, and non-split domination. Formulas for the split and non-split domination numbers of tenement graphs are presented based on the number of vertices. Theorems are presented stating that the mid vertex set of a tenement graph is always a split dominating set, but its size is not always equal to the split domination number.
This document summarizes research on generalized Cantor sets and functions where the standard construction is modified. It introduces Cantor sets defined by an arbitrary base where the intervals removed at each stage are not all the same length. It also defines irregular or transcendental Cantor sets generated by transcendental numbers like e. The key findings are:
1) There exists a unique probability measure for generalized Cantor sets that generates the cumulative distribution function.
2) The Holder exponent of generalized Cantor sets is shown to be logn/s where n is the base and s is the number of subintervals.
3) Lower and upper densities are defined for the measure on generalized Cantor functions and their properties are
SYMMETRIC BILINEAR CRYPTOGRAPHY ON ELLIPTIC CURVE AND LIE ALGEBRABRNSS Publication Hub
1) The document discusses symmetric bilinear pairings on elliptic curves and Lie algebras in the context of cryptography. It provides an overview of the theoretical foundations and applications of combining these areas.
2) Key concepts covered include the Weil pairing as a symmetric bilinear pairing on elliptic curves, its properties of bilinearity and non-degeneracy, and efficient computation. Applications of elliptic curves in cryptography like ECDH and ECDSA are also summarized.
3) The security of protocols like ECDH and ECDSA relies on the assumed difficulty of solving the elliptic curve discrete logarithm problem (ECDLP). The document proves various mathematical aspects behind symmetric bilinear pairings and their use in elliptic curve cryptography.
SUITABILITY OF COINTEGRATION TESTS ON DATA STRUCTURE OF DIFFERENT ORDERSBRNSS Publication Hub
This document summarizes research investigating the suitability of cointegration tests on time series data of different orders. The researchers used simulated time series data from normal and gamma distributions at sample sizes of 30, 60, and 90. Three cointegration tests (Engle-Granger, Johansen, and Phillips-Ouliaris) were applied to the data. The tests were assessed based on type 1 error rates and power to determine which test was most robust for different distributions and sample sizes. The results indicated the Phillips-Ouliaris test was generally the most effective at determining cointegration across different sample sizes and distributions.
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إضغ بين إيديكم من أقوى الملازم التي صممتها
ملزمة تشريح الجهاز الهيكلي (نظري 3)
💀💀💀💀💀💀💀💀💀💀
تتميز هذهِ الملزمة بعِدة مُميزات :
1- مُترجمة ترجمة تُناسب جميع المستويات
2- تحتوي على 78 رسم توضيحي لكل كلمة موجودة بالملزمة (لكل كلمة !!!!)
#فهم_ماكو_درخ
3- دقة الكتابة والصور عالية جداً جداً جداً
4- هُنالك بعض المعلومات تم توضيحها بشكل تفصيلي جداً (تُعتبر لدى الطالب أو الطالبة بإنها معلومات مُبهمة ومع ذلك تم توضيح هذهِ المعلومات المُبهمة بشكل تفصيلي جداً
5- الملزمة تشرح نفسها ب نفسها بس تكلك تعال اقراني
6- تحتوي الملزمة في اول سلايد على خارطة تتضمن جميع تفرُعات معلومات الجهاز الهيكلي المذكورة في هذهِ الملزمة
واخيراً هذهِ الملزمة حلالٌ عليكم وإتمنى منكم إن تدعولي بالخير والصحة والعافية فقط
كل التوفيق زملائي وزميلاتي ، زميلكم محمد الذهبي 💊💊
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𝐃𝐢𝐬𝐜𝐮𝐬𝐬 𝐭𝐡𝐞 𝐄𝐏𝐏 𝐂𝐮𝐫𝐫𝐢𝐜𝐮𝐥𝐮𝐦 𝐢𝐧 𝐭𝐡𝐞 𝐏𝐡𝐢𝐥𝐢𝐩𝐩𝐢𝐧𝐞𝐬:
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𝐄𝐱𝐩𝐥𝐚𝐢𝐧 𝐭𝐡𝐞 𝐍𝐚𝐭𝐮𝐫𝐞 𝐚𝐧𝐝 𝐒𝐜𝐨𝐩𝐞 𝐨𝐟 𝐚𝐧 𝐄𝐧𝐭𝐫𝐞𝐩𝐫𝐞𝐧𝐞𝐮𝐫:
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2. Adewuyi, et al.: Stakeholders’ perception of fish decline in the lagos lagoon
AEXTJ/Oct-Dec-2019/Vol 3/Issue 4 201
The lagoon’s biodiversity is further threatened by
polluting activities such as sawmilling and burning
of wood shavings at the Okobaba (OB) bank of the
lagoon which is the hub of thriving logging and
sawmilling industry. The incessant burning of saw
dust and wood shavings near the lagoon [Figure 1] is
point sources of priority pollutants such as polycyclic
aromatic hydrocarbons (PAHs) into the lagoon which
are known to be carcinogenic and mutagenic.[11]
A study of PAHs in subsurface water of some
sampled areas of the Lagos Lagoon showed a
total PAH concentration range between 8.90 and
13.30 µg/l.[12-15]
In the sediments, values between
12.32 to 955.51 µg/kg (Alani et al., 2013) and
365.5 to 1431.9 µg/kg[16-19]
have been reported
with a predominance of four to six-ring (high
molecular weight) PAHs especially benzo(a)pyrene
and pyrene attributed to combustion/pyrogenic
sources. Embryotoxic (adverse effects on embryos/
early life stages of animals) and teratogenic (effects
on ontogeny/development of an animal) effects
of sediment organic extracts have been observed
in vivo, such as in zebrafish (Danio rerio) embryos
(Sogbanmu et al., 2016) and in vitro as in cell
lines (Perez-Albaladejo et al., 2016). Furthermore,
sediment porewater has been shown to induce toxic
responses including acute developmental toxicity
and cardiac teratogenesis in D. rerio (Fang et al.,
2014). The effects of pollutants on the early life
stages of fish provides a forecast on the availability
and sustainability of fisheries in aquatic ecosystems
(Mumuni and Sogbanmu 2018; Sogbanmu et al.,
2018).The clamor for animal alternatives in research
and rapid high-throughput assays to provide bases
for environmental management and policies has
informed the use of the early life stages of fish
species as a globally ratified method relating to the
principle of the 3 Rs. (replacement, refinement, and
reduction) (Organization for Economic Cooperation
and Development [OECD] 2013). Model fish
species indigenous to various countries have been
utilized such as the Zebrafish (D. rerio), fathead
minnow (Pimephales promelas), rainbow trout
(Oncorhynchus mykiss), and Japanese medaka
(Oryzias latipes).[6-10]
The African sharptooth
catfish (Clarias gariepinus), a commercially and
ecologically important fish species in Nigeria is
a suitable model with well-documented general
biology, transparent eggs, easy to culture, and
year-round reproduction (Nguyen and Janssen,
2001). The embryos can be spawned artificially and
development from fertilization to hatching occurs
within 24–29 h post-fertilization at 28–29°C.[20-29]
To sustainably manage coastal ecosystem resources,
particularly in the face of current global climate
change, there is a need to engage stakeholders in such
management programs. The stakeholders include
coastal aboriginal communities who consume an
average of 15 times more seafood per capita than non-
aboriginal people.[30]
However, the level of awareness
of stakeholders about the environmental and human
health risks of their direct or indirect potentially
polluting activities on coastal ecosystems is low
particularly in developing nations.[31]
There is limited
information on the OB community stakeholders’
awareness about the environmental and human
health risks of their activities on the lagoon. The
dearth of information on the impact of sediments on
native fish species, particularly their early life stages
and perception of pollution in the OB community
provided an impetus for this study. Consequently, the
study aim was to investigate the environmental risks
perception of stakeholders and the effects of sawmill
activities at the OB hub of the Lagos Lagoon on
embryos of C. gariepinus.This will aid understanding
of the nature and extent of biological impacts of the
associated pollutants on fish species for the purpose
of targeted environmental management.
MATERIALS AND METHODS
Study area
The study areas were OB (test site) and University
of Lagos high rise (HR) building area (reference/
Figure 1: Okobaba area near the Lagos Lagoon, Nigeria
showing the nature of anthropogenic activity
3. Adewuyi, et al.: Stakeholders’ perception of fish decline in the lagos lagoon
AEXTJ/Oct-Dec-2019/Vol 3/Issue 4 202
control site) on the Lagos Lagoon [Figure 2].
OB is located adjacent to zones with sawmills,
timber transport, and municipal waste discharge
while the reference site is located adjacent to the
University of Lagos staff quarters. Three stations
were sampled at each of the two study sites. The
stations were geo-referenced with the aid of global
positioning system and recorded as coordinates
of the locations [Figure 2]. Photographs of the
anthropogenic activities around the test site are
shown in Figures 1 and 3.
Questionnaire administration
Structured questionnaires were administered to
stakeholders (Sawmillers, fishermen, traders, and
residents) at the test site (OB) centered around their
perception of the environmental risks and potential
impacts of their activities on the Lagos Lagoon
(Awodele et al., 2014). A pilot study was conducted
at OB before the main fieldwork in which a total of
ten sawmillers and ten community dwellers were
interviewed as respondents. The purpose of the pilot
studywastodeterminethereliabilityofthequestions,
difficulty level, whether the questions were free
from ambiguity and whether it had the power to
discriminate over results. For the administration
of the structured questionnaires, the total sample
population that was selected randomly for the
study was 100, made up of 40 sawmillers and 60
community dwellers at OB and its environs (Olawuni
and Okunola, 2014). The target populations among
the community dwellers were fishermen, traders,
young adults, and the residents of the saw mills
vicinity near the lagoon. The information obtained
from the various respondents includes; demographic
characteristics of the community, source and
preservation of wood logs, means of livelihood, and
waste management practices around the lagoon.
Surface water and sediment samples collection
from the Lagos Lagoon
Surface water and sediment samples were collected
in the wet (June 2016–August 2016) and dry
(December 2016–January 2017) seasons. The water
samples were collected with the aid of amber-
colored glass bottles, while sediment samples were
collected with Van Veen Grab into foil papers from
three sampling points each at the test and reference
sites on the Lagos Lagoon.All samples were labeled
and stored in ice-packed (temperature: 4°C) coolers
before transportation to the Analytical Laboratory at
the Department of Chemistry, University of Lagos,
Nigeria for analysis. The samples from the three
sampling points at each site were composite before
analyses (Sogbanmu et al., 2016).
Surface water and sediment physicochemical
analysis
Surface water physicochemical parameters
(temperature, pH, conductivity, dissolved oxygen
[DO], total dissolved solids [TDS], and salinity)
Figure 2: Map of the study area showing sampling locations
on the Lagos Lagoon, Nigeria
Figures 3: (a-d) Pictures of (a) saw dust on the water,
(b) sawmilling sheds, (c) wood logs and solid wastes on
water surface, (d) burning of saw dust and thick mass of
tree logs on the lagoon and human activity of the water
surface around the Okobaba study area of the Lagos
Lagoon. (a and b) Adewuyi, T. A. – June 2016–August
2016 (wet season) sampling pictures; (c and d) Sogbanmu,
T. O. – February 2017 (dry season) sampling pictures
dc
ba
4. Adewuyi, et al.: Stakeholders’ perception of fish decline in the lagos lagoon
AEXTJ/Oct-Dec-2019/Vol 3/Issue 4 203
were measured in situ using Horiba U50G
multi-water sampler.
For the sediments, physicochemical parameters
such as total organic carbon (TOC), particle size,
pH, conductivity, and physical appearance were
analyzed. The particle size distribution of the
sediments was determined by a wet sieving and
sedimentation technique according to the British
Standard Method for Soils.[33]
Sediment pH was
determined after adding 0.01 mol/l CaCl2
(10 ml)
to 5 g of each sediment and shaken for 1 h.
Walkley-Black titrimetric method was used to
determine TOC and total organic matter. Oil and
grease were extracted ultrasonically (acetone:
n-hexane, 50:50v/v) and quantified gravimetrically
(Hong et al., 2003). The concentration of an
analyte in blanks was subtracted from field
samples.
Samples extraction and analysis of PAHs
Samples extraction
For water samples extraction, 250 ml of water
samples were liquid-liquid extracted using hexane
and dichloromethane (DCM) mixture (1:1 v/v),
according to Kafildazeh et al. (2011). Water samples
were extracted thrice using 50, 30, and 20 ml of the
solvent mixture. The solvents were combined, dried
with anhydrous sodium sulfate, and concentrated
using nitrogen gas. The extract was reconstituted
with 2 ml of n-hexane and DCM (1:1) and analyzed
for PAHs using Gas Chromatograph (GC) (Agilent
Technologies 6890N, GC system) coupled with
Flame Ionization Detector (GC–FID).
Sediment porewater samples extraction was
conducted according to Fang et al. (2014). Briefly,
5 g of sediment samples were centrifuged in glass
centrifuge tubes at 3000 rpm for 30 min to separate
the porewater from the sediment. The porewater
was collected, filtered into glass vials (this served
as the crude porewater), extracted and analyzed in a
similar manner to the water sample. Briefly, 5 ml of
porewater was liquid-liquid extracted as the water
samples using 5, 2, and 1 ml of extracting solvent.
The extract was reconstituted using 1 mL of hexane/
DCM (1:1) and kept in amber vials for analysis of
PAHs using GC–FID.
For sediment organics extraction, 5 g of sediment
samples were freeze-dried and 2 g of treated
copper turnings (copper turnings were treated
by adding 0.1 M concentrated nitric acid until
the outer layers were corroded after which the
copper turnings were washed thoroughly with
distilled water and kept in methanol for the use
to prevent sulfur interference) were added to the
sample and left overnight for 24 h (Sojinu et al.,
2013). Thereafter, the sediment samples were
ultrasonicated thrice using 10 ml, 6 ml, and 3 ml
hexane/acetone (1:1v/v) mixture for 30 min,
respectively. The extracts were combined and
concentrated using nitrogen. The extracts were
reconstituted with 5 ml of hexane. Sample cleanup
was done using Supelco solid phase extraction
C18 cartridges that have been conditioned with
methanol. The elution of the PAHs was done using
2 ml of hexane/DCM (1:1 v/v). The eluate was
analyzed using GC-FID.
Quality control and calibration
Reagent blank was carried out for the water sample
using distilled water extracted with hexane/DCM
solvent used for the liquid-liquid extraction. For
the sediment sample, a certified reference material
(clay loam two soil certified reference material
[CRM] 131 by Sigma-Aldrich) was used. The CRM
was ultrasonicated and extracted for PAHs like the
sediment samples. Spiked recovery method was
used for validation studies of the sediment samples.
The samples were spiked with 1 µl of 100 ppm
standard mixture containing the 16 priority PAHs
(naphthalene, acenaphthylene, acenaphthene,
fluorene, phenanthrene, anthracene, fluoranthene,
pyrene, benzo(a)anthracene, chrysene, benzo(b)
fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene,
indeno(1,2,3-cd)pyrene, dibenzo(a,h)anthracene,
and benzo(g,h,i)perylene) before extraction. The
spiked samples were extracted and analyzed.
The recoveries were between 75% and 105% for
both the spiked and certified reference standard, and
certified levels were obtained for PAHs in the CRM.
A mixed standard of the 16 priority PAHs was used
forexternalcalibrationoftheinstrument.Calibration
standards were prepared by serial dilution of stock
solution with DCM. A calibration curve was plotted
for each of the PAHs. All the calibration plots for
the16 PAHs had R2
=0.98–0.99 and were used to
quantify the PAHs.
5. Adewuyi, et al.: Stakeholders’ perception of fish decline in the lagos lagoon
AEXTJ/Oct-Dec-2019/Vol 3/Issue 4 204
Instrumental and analytical conditions
The concentrations of the PAHs were determined
using a GC-FID. Nitrogen gas was used as the
carrier gas with a flow rate of 40 ml/min, hydrogen
with air produced the flame. Temperature for sample
injection was 250°C and the volume of sample
injected manually was 10 µl in a split mode with a
split ratio of 100:1. The GC oven temperature was
programmed from 70°C to 175°C at 15°C min−1
then to 215°C at 10°C min−1
then to 265°C held for
0 min at 20°C min−1
to 290°C held for 8 min. The
run time was 42.25 min. The column was HP5 and
the length of the column was 30 m with an internal
diameter of 0.32 mm and thickness of 0.25 µm.
Sediment organics and porewater extraction for
embryotoxicity studies
Sediment organics extraction was conducted
as described in samples extraction above and
was solvent exchanged with acetone. The crude
sediment organic extract (CSE) stock solution was
equivalent to 1 g dry weight sediment equivalent
extract (eQsed) per milliliter while the cleaned up
sediment organic extract (CUSE) stock solution was
equivalent to 2.5 g dry weight sediment equivalent
extract (eQsed) per ml. Sediment porewater was
extracted (as described in samples extraction). The
crude sediment porewater (CPW) stock solution
was equivalent to 1 g wet weight sediment (eQsed)
per ml while the cleaned up sediment porewater
extract (CUPW) stock solution was equivalent to 5 g
wet weight sediment porewater equivalent extract
(eQsed) per ml. Acetone was used as a control.
Embryotoxicity studies with African sharptooth
catfish (C. gariepinus) embryos
Spawning of C. gariepinus embryos
C. gariepinus (chordata, osteichthyes, siluriformes,
andclariidae)embryoswerespawnedfromunexposed
broodstock (1 female and 2 males) purchased from
the University of Lagos fish farm according to
OECD (2013) and Sogbanmu et al. (2018). Briefly,
one female broodstock C. gariepinus (weight range:
1.1 kg; length range: 45 cm) was injected with
Ovaprim(SyndelLaboratoriesLtd.,Canada)hormone
at 0.5 ml/kg of fish.After 10 h latency period, a slight
pressure was applied on the abdomen of the female,
leading to a running out of the eggs which were
collected into a plastic bowl. Two males (weight
range: 1.0 ± 0.5 kg; length range: 48 ± 1.1 cm) were
euthanized and the testes were carefully removed
with the aid of a new razor blade. An incision was
carefullymadeoneachtestistoletoutthemiltusedfor
fertilizing the eggs. Fertilization was aided with the
addition of saline water to the mixture and the bowl
was gently swirled to ensure adequate mixing of the
milt with the eggs. Fertilized eggs were identified and
confirmed with the aid of a stereomicroscope (Ceti
Star – 13 ED Stereomicroscope, Medline Scientific,
United Kingdom). Fertilization was considered to
have occurred when the egg-yolk was transparent
greenish-orange and cell division was clearly visible
in the blastodisc (Oellermann, 1995; Mumuni and
Sogbanmu, 2018).
Experimental design for embryotoxicity studies
A total of 30 embryos (10 embryos in triplicates)
per concentration were exposed to sediment organic
extracts (crude and cleaned up) and porewater
(crude and cleaned up) in Petri dishes from 0 to 26 h
post-fertilization (hpf) in 40 ml of dechlorinated
water (Sogbanmu et al., 2016). The exposure
concentrations used were; 1 mg eQsed/ml (CPW),
250 µg eQsed/ml (CSE), and 1.25 mg eQsed/
ml (CUPW and 250 µg eQsed/ml (CUSEs). Two
controls were included; embryos in water alone and
embryos exposed to acetone 0.25 µl/ml (0.025% of
the highest concentration of sediment extract). The
endpoints that were assessed in the embryos were
mortality, hatching success, and developmental
abnormalities using a stereomicroscope (Ceti Star
– 13 ED Stereomicroscope, Medline Scientific,
United Kingdom). Mortality was measured as the
percentage of coagulated embryos with no structures
and/or embryos with no visible heartbeat (Kumar
et al., 2013). Hatching success was measured as
the percentage of embryos that hatched (fully
emerge from the chorion) at 26 hpf. Developmental
abnormalities were calculated as the percentage of
embryos observed under the dissecting microscope
with one or more developmental abnormalities
such as pericardial edema, yolk-sac edema, curved,
and/or stunted tail and scoliosis (Mumuni and
Sogbanmu, 2018).
6. Adewuyi, et al.: Stakeholders’ perception of fish decline in the lagos lagoon
AEXTJ/Oct-Dec-2019/Vol 3/Issue 4 205
Statistical analysis
The analysis of the responses data from the
questionnaire administration is presented in
frequency distribution tables with percentages
(Awodele et al., 2014). Physicochemical parameters
and PAH levels in surface water and sediments
as expressed as mean ± standard deviation. The
embryotoxicity (mortality, hatching success, and
developmental abnormalities) data are expressed
as mean ± standard error. One-way Analysis of
Variance was used to test for significant differences
between treatment means (physicochemical
parameters and embryotoxicity data) and controls.
t-test was used to test the significant differences in
PAHs data between sites and seasons. Post-hoc tests
were conducted using Duncan’s Multiple Range
Test (Duncan, 1955) with the level of significance
set at P 0.05. Statistical analyses were conducted
using SPSS version 22.0. Figures were prepared
using Microsoft Excel version 2010.
RESULTS
Demographic data of respondents at the OB
sawmills
The socio-demographics data revealed that male
respondents were higher in number for the two
groups of respondents (sawmillers and community
dwellers) [Figure 4]. Similarly, respondents in
the age range of 31–35 years were highest for the
two groups. Most respondents had other forms of
education (informal). The highest percentages of the
community dwellers reside in OB while the highest
percentage of the sawmillers reside in other areas.
The number of years of experience of the sawmillers
on the job was between 3 and 10 years while most
respondents in the community were students. The
demography of more than 75% of the respondents
in this study was adults (16 y and above), hence,
their responses are reliable [Figure 4].
Stakeholders’ perception about environmental
risks and wastes management at the OB
sawmills
The sole means of transportation of wood logs to
the sawmill was through the lagoon, as agreed by
all respondents [Table 1]. Solignum was identified
as the main insecticide used to treat wood logs and
most respondents agreed that over 10 logs were
processed in each factory weekly. Over 90% of
respondents agreed that saw dust and associated
wood wastes are dispersed by water into the lagoon
and continuous burning is employed to reduce the
piles of wood wastes. Some respondents attested
to health effects associated with smoke from the
wood wastes burning and these wastes adversely
impact the color of the lagoon water as strongly
agreed by most respondents [Table 1]. These wastes
were noted to cause a rise in the sediment level
in the lagoon. Most respondents strongly agreed
that they bath in the lagoon; the lagoon exudes a
foul smell and reduction in fish catch was noted
[Table 1]. As regard domestic wastes management,
most respondents recycle the waste materials, dump
solid wastes at the bank of the lagoon where they
are burnt and end up in the lagoon. Basic sanitation
and hygiene facilities such as public toilets were
not available around the study area; hence, most
respondents defecate directly into the lagoon
through wastewaters are not disposed into the
lagoon [Table 1].
Physicochemical characteristics of surface
water and sediments at test sites on the Lagos
Lagoon
The surface water physicochemical parameters at
both sites and seasons were within set limits by
National Environmental Standards and Regulations
Enforcement Agency (NESREA) except for DO
values in the dry season at OB which was lower than
Figure 4: Demographic data of sawmillers and community
dwellers at okobaba
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the set limit and TDS values at both sites in the dry
season [Table 2]. Further, there were no significant
differences (P 0.05) in the physicochemical
parameters values between the control and test sites
in either of the seasons. However, conductivity,
TDS, and salinity values were higher in the dry
season compared to the wet season at both sites
[Table 2].
The percentage TOC in the sediment was higher
at the test site compared to the control site in both
seasons. Further, the % TOC was higher in the
wet season compared to the dry season at both
sites [Table 3]. The sediment pH was generally
acidic across the two sites and seasons, though,
the acidity was higher in the wet season compared
to the dry season. Conductivity was higher at the
test site in the wet season compared to the dry
season, while the reverse was the case for the
control site [Table 3]. The percentage sand and
silt particles size were higher in the wet season
at both sites compared to the dry season, though,
percentage clay particle size was higher in the
dry season compared to the wet season at OB
[Table 3].
PAHs concentration in surface water, sediments
and porewater of the Lagos Lagoon
The highest total PAHs in this study were recorded in
the sediments from the control site in the wet season
which was significantly higher (P 0.05) than
values recorded for sediments from OB [Table 4].
Table 1: Stakeholders’ perception about environmental risks and wastes management at the okobaba sawmills
Category Specific questions SA
Freq. (%)
A
Freq. (%)
D
Freq. (%)
SD
Freq. (%)
Transport and preservation
of wood logs
Logs are transported through the lagoon 124 (82.1) 27 (17.9) 0 (0) 0 (0)
Treatment of logs with aldrin 0 (0) 0 (0) 16 (33.3) 32 (66.7)
Treatment of logs with chlo dane 0 (0) 0 (0) 80 (100) 0 (0)
Main insecticide used to treat logs is solignum 140 (90.3) 15 (9.7) 0 (0) 0 (0)
More than 10 logs are processed weekly by each factory 72 (56.7) 33 (26) 22 (17.3) 0 (0)
Wood logs processing is done in each factory daily 72 (55) 45 (34.4) 14 (10.7) 0 (0)
Storage and management of
saw dusts
Dispersal of stored saw dust and other wood wastes by water
into the lagoon
100 (72.5) 30 (21.7) 8 (5.8) 0 (0)
Continuous burning of saw dusts and other wood wastes to
reduce their piles
112 (75.7) 36 (24.3) 0 (0) 0 (0)
Health effects from charred saw dust smoke to stakeholders 28 (23.9) 69 (59) 20 (17.1) 0 (0)
Sawmills wastes adversely impacts the color of the lagoon
water
128 (87.1) 12 (8.2) 6 (4.1) 1 (0.7)
Sawmills wastes cause a rise in the lagoon sediment level 120 (81.6) 24 (16.3) 2 (1.4) 1 (0.7)
Saw dusts are transported through the lagoon from adjacent
communities
80 (66.1) 18 (14.9) 18 (14.9) 5 (4.1)
Anthropogenic activities
near or in the Lagoon
Community dwellers bath in the lagoon 132 (68) 36 (18.6) 22 (11.3) 4 (2.1)
The lagoon water exudes foul smell 132 (64.1) 66 (32) 6 (2.9) 2 (1)
Fish sellers around the lagoon smoke fish at their stands 16 (10.5) 93 (61.2) 36 (23.7) 7 (4.6)
There is drastic reduction in the number of fishes in the lagoon 184 (86) 9 (4.2) 20 (9.3) 1 (0.5)
Wastes management Community dwellers dump domestic solid wastes at the bank
of the lagoon
168 (76.7) 45 (20.5) 6 (2.7) 0 (0)
Solid wastes are segregated before dumping at the bank of the
lagoon
0 (0) 15 (12.4) 102 (84.3) 4 (3.3)
Wastes end up in the lagoon 104 (62.3) 48 (28.7) 14 (8.4) 1 (0.6)
Wastes are dumped and burnt at the shore of the lagoon 204 (92.7) 6 (2.7) 6 (2.7) 4 (1.8)
Public toilets are available in and around the lagoon
waterfront
0 (0) 6 (5.6) 88 (81.5) 14 (13)
Community dwellers defecate directly in the lagoon 168 (85.35) 12 (6.1) 6 (3) 11 (5.6)
Wastewaters are disposed into the lagoon 4 (3.2) 15 (12) 104 (83.2) 2 (1.6)
Wastewaters are pre-treated before disposal into the lagoon 0 (0) 0 (0) 74 (76.3) 23 (23.7)
SA: Strongly agree, A: Agree, D: Disagree, SD: Strongly disagree, Freq.: Frequency of responses, %: Percentage of responses
8. Adewuyi, et al.: Stakeholders’ perception of fish decline in the lagos lagoon
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Total PAHs in OB porewater and surface water were
higher than the values for the control site. In the dry
season, the total PAHs in the sediment at the control
site were higher than the values recorded for OB
[Table 4]. However, this value was significantly
lower (P 0.05) than the value recorded at the
control site in the wet season.
Furthermore, the total PAHs in the OB porewater
was significantly lower (P 0.05) in the dry
season compared to the wet season. There were no
significant differences (P 0.05) in the total PAHs
between the test and control sites in the dry season.
In general, in the wet and dry seasons, the order of
decreasing total PAHs was sediment porewater
surface water.
Embryotoxicity studies of Lagos Lagoon sediment
organics extracts and porewater on C. gariepinus
Mortality was highest in the cleaned up porewater
from the control site (HR) (CUPW-HR) followed
by the CPW-HR, CPW-OB, crude sediment organic
extract-OB (CSE-OB) compared to the controls as
well as CUPW-OB and sediment organic extracts
(CUSE-OB) from OB [Figure 5].
Hatching success was highest in the controls, CUSEs
(CUSE-OB) and porewater (CUPW-OB) from OB.
Hatching success was lowest though higher than
50% in cleaned up porewater from the control site
(CUPW-HR) [Figure 5].
The percentage abnormalities were highest in
the CUPW from the control site (HR) and lowest
water control. There were no significant differences
(P 0.05) in the mortality, hatching success and
abnormalities observed in the crude and CUSEs,
porewater, and controls [Figure 5].
DISCUSSION
In this study, we evaluated stakeholders’
environmentalrisksperceptionandeffectsofsawmill
activities on embryos of the African Sharptooth
catfish. The socio-demographic characteristics
of respondents in this study showed that the high
level of informal education (or low level of formal
education) might be a reason for the paucity of
Table 2: Physicochemical parameters of Lagos Lagoon surface water in the wet and dry season, 2016–2017
Parameter Wet season Dry season NESREA
Okobaba High rise Okobaba High rise Limits
Temperature (°C) 26.12±1.17 26.69±1.06 28.29±0.40 29.25±0.16 40
pH 8.16±0.57 9.35±1.57 6.75±0.06 6.67±0.15 6.5-8.5
Conductivity (mS/cm) 0.97±0.18 1.22±0.29 28.83±1.68 30.83±0.06 NS
Dissolved oxygen (mg/l) 9.68±5.18 8.85±3.39 4.34±0.74 9.72±3.96 6.0
Total dissolved solids (g/l) 0.65±0.06 0.76±0.20 17.90±1.04 18.83±0.06 2
Salinity (%) 0.44±0.10 0.61±0.14 17.40±1.01 19.13±0.06 NS
Values are Mean±SD (n=3); NESREA, 2010; NS: Not specified, NESREA: National Environmental Standards and Regulations Enforcement Agency
Table 3: Physicochemical parameters of Lagos Lagoon sediments in the wet and dry season, 2016–2017
Parameters Wet season Dry season
Okobaba High rise Okobaba High rise
TOC (%) 2.32±1.30 0.88±0.44 1.64±1.30 0.58±0.63
Grain particular size (%) Gravel; 0 Gravel: 0 Gravel: 0 Gravel:0
Sand: 15–22 Sand: 23-25 Sand:7.1-10 Sand: 21–23
Silt: 28–31 Silt: 35-37 Silt: 27-30 Silt:33–35
Clay: 50–54 Clay: 42-45 Clay: 63-67 Clay: 40–42
pH 4.13±0.50 4.86±0.92 5.92±0.50 5.25±1.00
Conductivity (dS/cm3
) 4927±2546 2522±1379 772±254 9473±139
Physical appearance Dark grey Dark grey Dark grey Dark grey
organic silty organic silty organic silty Organic silty
clay clay Clay Clay
TOC: Total organic carbon; n=3, Values are Mean±SD
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Table4:PAHsconcentrationinsurfacewater,sediments,andporewateroftheLagosLagooninthewetanddryseasons,2016–2017
PAHs
(mg/l/mg/kg)
surface
Water
OkobabaWetseasonHighrise(control)Surface
water
OkobabaDryseasonHighrise(control)
SedimentSurface
Water
Pore
water
Pore
water
SedimentPore
water
SedimentSurface
water
Pore
water
Sediment
Naphthalene0.03±0.030.75±0.931.37±1.650.03±0.030.75±0.931.66±2.150.01±0.000.21±0.000.81±0.550.01±0.010.21±0.000.22±0.29
Acenaphthylene0.03±0.010.67±0.281.27±0.460.03±0.030.63±0.221.48±0.800.02±0.000.50±0.001.05±0.070.01±0.010.50±0.000.55±0.65
Acenaphthene0.29±0.470.78±0.481.47±0.800.15±0.230.73±0.404.38±7.750.02±0.000.50±0.001.01±0.010.01±0.010.50±0.001.01±0.00
Fluorene0.03±0.010.53±0.060.95±0.630.02±0.010.49±0.001.69±1.200.02±0.000.49±0.000.99±0.000.01±0.010.50±0.000.59±0.58
Phenanthrene0.16±0.210.45±0.120.88±0.280.02±0.000.45±0.122.06±0.890.05±0.040.52±0.011.04±0.010.01±0.010.52±0.001.33±0.41
Anthracene0.13±0.112.23±2.964.43±5.950.09±0.112.23±2.965.53±5.320.02±0.000.56±0.001.13±0.000.01±0.010.57±0.000.77±0.51
Fluoranthene2.11±1.610.65±0.091.26±0.100.03±0.010.65±0.091.35±0.240.10±0.110.60±0.001.20±0.000.13±0.010.60±0.001.51±0.44
Pyrene0.09±0.122.16±2.984.30±5.980.09±0.132.16±2.984.41±5.880.02±0.000.56±0.001.13±0.010.02±0.010.56±0.001.59±0.66
Benz(a)0.06±0.040.78±0.371.54±0.590.03±0.020.71±0.274.57±6.000.02±0.000.56±0.011.11±0.000.01±0.010.35±0.301.11±0.00
Anthracene
Chrysene0.17±0.260.36±0.280.75±0.500.02±0.010.36±0.280.81±0.390.02±0.000.52±0.011.035±0.010.01±0.010.42±0.151.04±0.00
Benzo(b)0.37±0.531.05±0.781.99±1.320.04±0.041.03±0.767.06±9.990.02±0.000.60±0.011.19±0.000.02±0.020.40±0.281.20±0.00
Fluoranthene
Benzo(k)
fluoranthene
0.06±0.030.68±0.581.36±1.170.03±0.020.68±0.582.72±1.170.04±0.001.02±0.002.04±0.000.03±0.031.02±0.002.05±0.00
Ene
Benzo(a)pyrene0.03±00.78±0.011.51±0.080.03±00.78±0.011.63±0.110.03±0.000.78±0.001.55±0.000.02±0.020.46±0.441.55±0.00
Indeno
(1,2,3,c-d)
0.03±0.010.54±0.061.03±0.060.02±0.010.53±0.074.82±6.290.02±0.000.52±0.021.03±0.050.01±0.010.68±0.001.53±0.00
Pyrene
Dibenz(a,h)
anthra
0.03±0.020.71±0.181.23±0.300.03±0.010.65±0.202.30±1.260.03±0.010.53±0.001.06±0.000.01±0.010.68±0.001.53±0.00
Cene
Benzo(g,h,i)0.56±0.870.54±0.420.97±0.750.39±0.650.52±0.438.00±8.560.02±0.000.27±0.000.59±0.060.02±0.010.74±0.000.63±0.00
Perylene
∑PAHs4.18±4.3313.66±10.58*26.31±20.1a
1.05±1.0013.35±9.4554.57±50.00b*
0.46±0.118.74±0.06**17.38±0.770.46±0.208.74±1.1717.97±3.54**
n=3,unitsforsurfacewaterandporewaterareinmg/lwhilesedimentsareinmg/kg,resultsarepresentedasmean±SD,*representssignificantdifferencebetweenseasonsforthesamemediawhiledifferentalphabetsuperscriptsrepresent
significantdifferencestestandcontrolsiteforthesamemediaandseasonatP0.05,PAHs:Polycyclicaromatichydrocarbons,a
ThisdenotedthatthesedimentfromOkobaba(testsite)islesssignificantwhencomparedtosedimentfrom
Highrise(controlsite)duringwetseason,b
*ThisdenotedthatsedimentfromHighriseishighlysignificantwhencomparedtosedimentfromOkobabaduringthewetseason.Also,sedimentfromHighriseduringthewetseasonishighly
significantwhencomparedtosedimentfromHighriseduringthedryseason,**ThisdenotedthatporewaterfromOkobabaduringthedryseasonislesssignificantwhencomparedtoporewaterfromOkobabaduringthewetseason.Also,
sedimentfromHighriseduringthedryseasonislesssignificantwhencomparedtosedimentfromHighriseduringthewetseason.
10. Adewuyi, et al.: Stakeholders’ perception of fish decline in the lagos lagoon
AEXTJ/Oct-Dec-2019/Vol 3/Issue 4 209
environmental responsibility and awareness of the
risks posed by the stakeholders’ activities. This has
been observed to be typical in rural areas and slums
in developing countries (Shen et al., 2013).
Furthermore, it was noted that most sawmillers
who are responsible for the major wastes generated
and disposed at the site do not reside in the
area. This might be responsible for the possible
indifference/ignorance to the environmental
and human health risks of their activities. The
stakeholders’ perception of environmental risks
revealed the nature of sawmill materials (wood
logs) transportation which is mainly through the
lagoon. This corroborates the observation by
some authors (Buraimoh et al., 2015; Elijah and
Elegbede, 2015) who reported similar results
in the study area. Furthermore, the number of
wood logs processed weekly combined with the
preponderance of sawmill factories at the site
reveals the reason for saw dusts being the major
waste generated. According to Abulude (2006),
about 104,000 cm3
of sawdusts is amassed daily
at these sawmills.
The use of solignum (active ingredient: Permethrin)
as the main insecticide for treating wood logs is
due to its efficacy in preserving and protecting
the wood from infestation by wood borers and
termites (Patrick-Iwuanyanwu et al., 2016) which
could reduce the marketability and/or quality of the
wood (Olajuyigbe and Oloyede, 2017). Solignum,
like other wood preservative chemicals such as
Timber guard and D-D Force, is sold in the open
market making them easily accessible to users like
sawmillers (Olajuyigbe and Oloyede, 2017).
The means of disposal of saw dusts which was
noted to be mainly by dumping and burning on the
bank of the lagoon may be due to the lack of land
area to store the massive quantities and poor/almost
inaccessible roads for wastes managers to collect
the wastes frequently. This agrees with Buraimoh
et al. (2015) who reported burning and dumping of
sawdusts into the lagoon as a means of disposal. The
poor esthetic value of the lagoon in terms of color as
strongly agreed by most respondents is corroborated
by Buraimoh et al. (2015) who attributed the loss
of esthetic value to the foul odor oozing from the
anaerobic decomposition of the saw dusts. Further,
health effects associated with the burning of the
sawmill wastes were noted by most respondents.
Pollutants such as carbon monoxide, sulfur dioxide,
nitrogen oxides, and particulate matter have been
associated with wood burning with attendant effects
on breathing and risks of lower respiratory infections
(Owoyemi et al., 2016). The lack of public toilets in
and around this urban slum (OB) as alluded to by
most respondents could be a reason for bathing and
defecating by stakeholders especially community
dwellers in the lagoon. These unsanitary acts may
cause skin infections (dermatitis), cholera due to
unintentional ingestion of the lagoon water and
other public health disease outbreaks associated
with a lack of sanitary facilities especially in
vulnerable persons (the elderly and children) (Boadi
and Kuitunen, 2002). The decline in fish catch in the
lagoonasnotedbymostrespondentsmightberelated
to the polluting activities at the test site as attributed
to in Buraimoh et al. (2015) and Owoyemi et al.
(2016). This creates anoxic conditions resulting in
the death or exodus of aquatic organisms. Recycling
options for these wastes such as use as poultry
animal bedding, garden mulch, and particle board
(Owoyemi et al., 2016), among others should be
considered as an environmental friendly and more
sustainable disposal method.
ThesurfacewaterDOvaluerecordedatOBinthedry
season which was lower than the NESREAlimit may
be attributed to preponderance of organic pollutants
(sawdusts) could result in anoxic conditions due
to the action of microorganisms (Buraimoh et al.,
Figure 5: Embryotoxicity indices in Clarias gariepinus
embryos exposed to extracts of sediments from test and
reference sites on the Lagos Lagoon from 0 to 26 h post-
fertilization. n=3 replicates, values are represented as %
mean ± standard error. Exposure concentrations: 1 mg eQsed/
ml (CPW), 250 µg eQsed/ml (CSE), 1.25 mg eQsed/ml
(CUPW), 250 µg eQsed/ml (CUSE), 0.25 µl/ml (acetone)
11. Adewuyi, et al.: Stakeholders’ perception of fish decline in the lagos lagoon
AEXTJ/Oct-Dec-2019/Vol 3/Issue 4 210
2015). Furthermore, the low DO may be related to
the high TDS value in the dry season at the test site
though a higher value was recorded at the control
site. In dry season, the water is more concentrated,
slightly acidic, had more dissolved solids and ions
which gave rise to higher conductivity and salinity.
The temperature of the lagoon was higher in the dry
season which is usually hotter.The lack of significant
differences in surface water physicochemical
parameters between the test and control site is rather
puzzling. The control/reference site was selected on
the basis of a lack of visible anthropogenic activity
except for its proximity to the University of Lagos
staff quarters. This may point to the very high
pollution status of the lagoon over the years. Since
water is not stagnant, its move across the lagoon
could transport pollutants from highly polluted
sections to hitherto unpolluted/lowly polluted areas.
The higher TOC values recorded in sediments at the
test site compared to the control may be because
of the continuous deposition of wood wastes at the
site which is majorly composed of carbon. Over
the years, this contributes to siltation of sediment
at the site as evidence by the high percentage of silt
and clay particle size in this study. Furthermore, the
characteristic color of the sediments is associated
with sediments that have organic matter present in
them. The high percentage TOC observed in the wet
season may be due to a higher deposition of wood
wastes into the surface water through run-off during
the heavy rains which eventually sink to the bottom
of the lagoon. Microorganisms act on this in the
sediment further compacting it (Buraimoh et al.,
2015). This might be responsible for the lower
sediment pH observed in the wet season compared
to the dry season. Sediment pH was noted to be
more acidic than surface water pH. This could be as
a result of accumulation of organics at the bottom of
the lagoon. Furthermore, the sediment conductivity
values were higher than the water samples showing
that there were more ions in the sediments probably
due to accumulated debris. The higher percentage
of sand and silt observed in the wet season may be
due to run off during rainfall from the bank of the
lagoon laden with saw mill wastes.[33-40]
The higher level of PAHs (especially high molecular
weight [4–6 rings] PAHs) in the sediments compared
to the surface water and porewater is consistent with
the findings of Sogbanmu et al. (2016) who reported
higher levels of PAHs in the sediments compared to
the surface water. Furthermore, organic pollutants
such as organochlorine pesticides have been found
to be highest in sediments followed by porewater
and least in surface water (Gakuba et al., 2018).
Sediments have been shown to act as sinks for PAHs
due to the hydrophobic nature of the latter. PAHs
adhere to organic matter in soil and sediments (Wang
et al., 2014). Moreover, the nature of the sediment, in
this case, organic, silty, and clayey can contribute to
the binding of organic compounds such as PAHs to
it. The significant decrease of PAHs in the porewater
from the test site in the dry season might be due
to the reduced remobilization of sediment PAHs
into the water column. The Lagos Lagoon is a tidal
water and suffers from longshore drift. It receives
water from the Atlantic Ocean during high tides and
returns water during low tides. During this process,
there is mixing of water (Badejo et al., 2014). The
findings in this study were similar to the findings
of Ololade et al. (2011) and Adekunle et al. (2017)
where higher concentrations of PAHs were recorded
during the wet season than in the dry season. The
cleaned up porewater in this study elicited the
highest embryotoxic responses (lowest hatching
success, highest mortality, and developmental
abnormalities). This may be attributed to the high
concentrations of PAHs detected in porewater
compared to surface water. Although sediment
PAHs were higher than porewater PAHs in this
study, the higher embryotoxic responses observed
in the porewater compared to the sediment organics
extractsmaybeduetotheconcentrationofporewater
tested which was 4 times higher than the sediment
organic extracts. The assumption for the disparity
in extract concentrations of porewater and sediment
organics was that sediment organic extracts would
be more toxic than the porewater since PAHs and
other organic contaminants have been shown to be
higher in sediments than porewater.
As observed in the previous results on
physicochemical parameters and PAHs values for
the test and control sites, embryotoxic responses
were highest in the extracts from the control site
comparedtothetestsite.Furthermore,thecleanedup
porewater and sediment organic extracts (containing
PAHs only) elicited higher embryotoxic responses
compared to the crude porewater and sediment
organic extracts at the control sites. This points to
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AEXTJ/Oct-Dec-2019/Vol 3/Issue 4 211
an unexpected source of pollution by PAHs which
are not related to significant anthropogenic activity
as seen at OB. Possible sources could be due to oil
spills from boats that cross the area, proximity to
the University of Lagos Lagoon front which is the
berthing point for boats used by some departments
in the university.
Conversely, the crude porewater (containing
inorganic pollutants) and sediment organic extracts
(containing organic pollutants including PAHs)
from OB (test site) elicited higher embryotoxic
responses compared to the cleaned up extracts
from the same site. This point to other pollutants
(both inorganic and organic) at the site which
are capable to eliciting higher embryotoxic and
perhaps more biotoxic effects than PAHs alone.
Potential inorganic pollutants that may be present
at OB though not evaluated in this study could be
heavy metals, surfactants, sulfates, nitrates, and
phosphates (Arimoro et al., 2007), among others.
Other organic pollutants that may be present which
are potentially toxic are pesticides particularly
Solignum (permethrin-based) which was noted by
most respondents in this study as the main wood
preservative and protectant (Patrick-Iwuanyanwu
et al., 2016), tannins, and lignins (Bailey et al.,
1999), among others.
The non-significant embryotoxic responses between
extracts and controls could be due to the low
concentrations tested (250 µg eQsed/ml) compared
to the concentrations (2.5–25 mg eQsed/ml) that
elicited significant embryotoxic effects in D. rerio
embryos exposed to Lagos Lagoon sediment organic
extracts (Sogbanmu et al., 2016).
CONCLUSIONS
Our results demonstrate the environmental and
potential human health risks posed by sawmill
activities at OB is mainly due to a lack of formal
education and the non-availability of efficient waste
management systems. In spite of the non-significant
differences observed in the embryotoxicity studies
with C. gariepinus embryos compared to the
control, the observed high mortality, low hatching
success, and high developmental abnormalities in
the extracts agrees with the observation of most
respondents regarding the decline in fish catch in
the lagoon. We recommend future studies such
as in situ monitoring studies using indigenous
fish and macro-invertebrates, evaluation of other
biomarkers in model aquatic organisms, evaluation
of other pollutants such as pesticides and heavy
metals in the sediment and water, species diversity
studies and stakeholders’ engagement for holistic
evaluation and management of pollution in the
study area. Furthermore, we recommend targeted
environmental management and stakeholders’
engagement to forestall further coastal degradation
and promote sustainable fisheries in the lagoon in
support of the UN sustainable development goal
three (life below water).
ACKNOWLEDGMENTS
This project was supported in part by funds from
the PADI Foundation to T.O Sogbanmu and a
research grant to T.A Adewuyi by the Society for
EnvironmentalToxicologyandPollutionMitigation.
DECLARATION OF INTEREST
The authors report that they have no conflicts of
interest.
ETHICAL APPROVAL
All applicable international, national, and/
or institutional guidelines for the care and use
ofanimals were followed. This study followed
the principles in the Declaration of Helsinki on
the humane treatment of animals used in research
(http://www.wma.net/en/30publications/10policies/
a18/) and the principles in the AVMA Guidelines for
the Euthanasia of Animals (AVMA, 2013).
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