First, I briefly review of selected recent studies which have improved our understanding of phytoplankton through the concept of optimality. Then, I present my most recent study of the combined effects of temperature and nutrient concentrations on the rates of nutrient uptake by phytoplankton. The point is that our assumptions about the fundamental dependencies affect our interpretation of the patterns observed in field experiments.
WOODY PLANT RICHNESS AND NDVI RESPONSE TO DROUGHT EVENTS IN CATALONIAN (NORT...Hibrids
This study examines the relationship between woody plant species richness and the impact of drought events on forest canopy cover, as measured by NDVI anomalies, across different forest types in Catalonia, Spain. Forest plot data on species richness were compared to satellite imagery showing NDVI responses during a major drought in 2003. The relationship between richness and NDVI response differed among forest types and interacted with climate, as summarized by the Thorntwaite index. In some drier forest types, lower richness was linked to greater NDVI decreases during drought, while the opposite pattern emerged in some moister forest types. The results suggest the diversity-stability relationship shifts across the regional climatic gradient.
Biodiversity conservation and global changeMarco Pautasso
Botanic gardens, human well-being, tree species distribution shifts, invasive species, risk management, sea-level rise, climate according to Walter & Lieth, land use patterns, carbon emissions of conservation biologists, NIMBY, topography
This document analyzes the relationship between flood rhythmicity and ecological patterns and processes in large tropical river systems. It finds that rivers with more rhythmic annual flooding, characterized by predictable timing and magnitude of flood peaks, tend to have higher fish species richness, more stable avian populations, and higher rates of riparian forest productivity compared to rivers with less rhythmic, unpredictable flooding. Climate change and human alterations like water extraction and dams are expected to disrupt the natural hydrologic rhythms of rivers with negative impacts on biodiversity and ecosystem function.
This research paper examines how plant species richness varies along a subtropical elevation gradient in eastern Nepal. The study analyzes species richness data from 1500 to 100 meters above sea level, divided into 15 100-meter elevation bands. Species were counted in standardized plots and assigned to different life forms, including trees, shrubs, climbers, herbs and ferns. Climate variables like potential evapotranspiration and mean annual rainfall were analyzed to explain variations in species richness of different life forms along the elevation gradient. The results found relationships between climate variables and species richness for woody life forms but not for herbaceous life forms. A water-energy dynamics model was found to explain 63-70% of the variation in species richness for
This document presents the River Continuum Concept, which proposes that the structural and functional characteristics of biological communities in rivers are adapted to conform to the physical conditions and energy flow patterns of the river system. It hypothesizes that from headwaters to mouth, there is a gradient of physical conditions in rivers that elicits responses in biological populations, resulting in consistent patterns of organic matter transport and use along the river's length. Communities are proposed to form a continuum with shredder and collector-dominated assemblages in headwaters transitioning to scraper-dominated in mid-sized rivers and collectors in large rivers, reflecting shifts in food resources with stream size.
OSJ 2019 : Practical Resilience Index for Coral Reef Assessmentanbiocore
This document proposes a new index for assessing coral reef resilience based on data collected from line-intercept transects. The index was modified from an existing soil resilience index. Six variables were statistically selected as resilience indicators: coral functional group, coral habitat quality, sand-silt cover, coral cover, coral small-size number, and algae-other-fauna cover. Maximum values of five variables were determined as the best state, while the maximum value of coral small-size number was determined from 1240 data sets of Indonesian reefs. The resilience index performed well in relation to changes in coral cover, algae-other-fauna cover, and sand-silt cover. Managers can use this tool to
This study developed empirical models to predict canopy arthropod biomass in arctic tundra based on measurements of the normalized difference vegetation index (NDVI). Models were created using data across four growing seasons and four distinct tundra vegetation communities in Alaska. The overall model, across all communities, explained 63% of variance in arthropod biomass. Models for individual communities explained 74-87% of variance. This research shows NDVI can quantify spatial and temporal dynamics of arthropod biomass, and lays groundwork for using air and satellite data to assess arthropod communities at larger scales.
Effects of temperature and prey density on trophic interaction in aquatic foo...Baptiste Jaugeon
This document summarizes a short-term laboratory experiment that investigated the effects of temperature and prey density on trophic interactions between the predator Chaoborus obscuripes and the prey Daphnia magna. Functional response experiments were conducted at two temperatures (16°C and 20°C) across a range of Daphnia densities. Metabolic rates of Chaoborus were also measured at each temperature. Results were used to model the effects on short-term predator-prey interaction strength and long-term predator energetic efficiency.
WOODY PLANT RICHNESS AND NDVI RESPONSE TO DROUGHT EVENTS IN CATALONIAN (NORT...Hibrids
This study examines the relationship between woody plant species richness and the impact of drought events on forest canopy cover, as measured by NDVI anomalies, across different forest types in Catalonia, Spain. Forest plot data on species richness were compared to satellite imagery showing NDVI responses during a major drought in 2003. The relationship between richness and NDVI response differed among forest types and interacted with climate, as summarized by the Thorntwaite index. In some drier forest types, lower richness was linked to greater NDVI decreases during drought, while the opposite pattern emerged in some moister forest types. The results suggest the diversity-stability relationship shifts across the regional climatic gradient.
Biodiversity conservation and global changeMarco Pautasso
Botanic gardens, human well-being, tree species distribution shifts, invasive species, risk management, sea-level rise, climate according to Walter & Lieth, land use patterns, carbon emissions of conservation biologists, NIMBY, topography
This document analyzes the relationship between flood rhythmicity and ecological patterns and processes in large tropical river systems. It finds that rivers with more rhythmic annual flooding, characterized by predictable timing and magnitude of flood peaks, tend to have higher fish species richness, more stable avian populations, and higher rates of riparian forest productivity compared to rivers with less rhythmic, unpredictable flooding. Climate change and human alterations like water extraction and dams are expected to disrupt the natural hydrologic rhythms of rivers with negative impacts on biodiversity and ecosystem function.
This research paper examines how plant species richness varies along a subtropical elevation gradient in eastern Nepal. The study analyzes species richness data from 1500 to 100 meters above sea level, divided into 15 100-meter elevation bands. Species were counted in standardized plots and assigned to different life forms, including trees, shrubs, climbers, herbs and ferns. Climate variables like potential evapotranspiration and mean annual rainfall were analyzed to explain variations in species richness of different life forms along the elevation gradient. The results found relationships between climate variables and species richness for woody life forms but not for herbaceous life forms. A water-energy dynamics model was found to explain 63-70% of the variation in species richness for
This document presents the River Continuum Concept, which proposes that the structural and functional characteristics of biological communities in rivers are adapted to conform to the physical conditions and energy flow patterns of the river system. It hypothesizes that from headwaters to mouth, there is a gradient of physical conditions in rivers that elicits responses in biological populations, resulting in consistent patterns of organic matter transport and use along the river's length. Communities are proposed to form a continuum with shredder and collector-dominated assemblages in headwaters transitioning to scraper-dominated in mid-sized rivers and collectors in large rivers, reflecting shifts in food resources with stream size.
OSJ 2019 : Practical Resilience Index for Coral Reef Assessmentanbiocore
This document proposes a new index for assessing coral reef resilience based on data collected from line-intercept transects. The index was modified from an existing soil resilience index. Six variables were statistically selected as resilience indicators: coral functional group, coral habitat quality, sand-silt cover, coral cover, coral small-size number, and algae-other-fauna cover. Maximum values of five variables were determined as the best state, while the maximum value of coral small-size number was determined from 1240 data sets of Indonesian reefs. The resilience index performed well in relation to changes in coral cover, algae-other-fauna cover, and sand-silt cover. Managers can use this tool to
This study developed empirical models to predict canopy arthropod biomass in arctic tundra based on measurements of the normalized difference vegetation index (NDVI). Models were created using data across four growing seasons and four distinct tundra vegetation communities in Alaska. The overall model, across all communities, explained 63% of variance in arthropod biomass. Models for individual communities explained 74-87% of variance. This research shows NDVI can quantify spatial and temporal dynamics of arthropod biomass, and lays groundwork for using air and satellite data to assess arthropod communities at larger scales.
Effects of temperature and prey density on trophic interaction in aquatic foo...Baptiste Jaugeon
This document summarizes a short-term laboratory experiment that investigated the effects of temperature and prey density on trophic interactions between the predator Chaoborus obscuripes and the prey Daphnia magna. Functional response experiments were conducted at two temperatures (16°C and 20°C) across a range of Daphnia densities. Metabolic rates of Chaoborus were also measured at each temperature. Results were used to model the effects on short-term predator-prey interaction strength and long-term predator energetic efficiency.
This document summarizes a presentation on modeling the effects of trait diversity on phytoplankton communities. It introduces mechanisms for sustaining trait diversity, including trait diffusion and "kill-the-winner," and presents results from a model exploring the short-term and long-term impacts of trait diversity on community productivity and growth rates under different frequencies of disturbance events. The model results show that an intermediate level of trait diversity is optimal and that the optimal level depends on the frequency and intensity of perturbations affecting the community.
This document examines how the assumption of homogeneous vs heterogeneous radioactive contamination in soil/sediment impacts the external radiation dose rates of fauna. It analyzes contamination profiles from sediment samples in Canada and soil samples in Austria involving various radionuclides. Dose conversion coefficients are calculated using a dosimetry model for different organisms, locations within the contaminated media, and exposure scenarios. The results show dose rates can vary by three orders of magnitude depending on the specific situation. The assumption of homogeneous contamination is not always conservative.
This document summarizes a presentation on predicting impacts of climate change on biodiversity. It discusses how climate changes influence biodiversity and the need to predict future impacts to support adaptation. Methods for predicting geographic ranges of species under climate change like bioclimatic and maximum entropy models are introduced. Examples are given of observed climate impacts and predictions of species range shifts and habitat losses. Limitations of these predictive approaches are also acknowledged.
The document summarizes research using a combination of food web and ecosystem modeling to show that impending catastrophic shifts in shallow lake ecosystems are preceded by a destabilization of the aquatic food web. Analysis of trophic interactions revealed that only a few key interactions involving zooplankton, diatoms, and detritus dictate the deterioration of food-web stability. This implies that changes in trophic organization may serve as an empirical indicator of ecosystem resilience and the risk of a regime shift.
Relationship Between Sampling Area, Sampling Size Vs...Jessica Deakin
This document discusses the importance of order in the public realm and how planning, zoning, transects, and urbanism theories help shape our environment. It mentions several authors who have discussed problems with urban design and provided solutions to make the public realm a better place. The document argues that by improving order and the urban framework, cities could become more cohesive in design.
WWF Study: Vulnerability analysis of the amazon biome ClimateCourse
This document provides an analysis of climate vulnerability in the Amazon biome and its protected areas. It begins with an overview of climate change impacts on the region, including increasing temperatures, more frequent droughts and floods, and increased forest fires. It then presents a conceptual framework for assessing climate risks and resilience. The methodology assesses exposure to climate hazards, climate risks to ecosystem services, and factors that build ecosystem resilience. Key findings include increased temperature across the biome, spatially variable drought and flood impacts, and concentration of fires in deforestation fronts. The analysis aims to support climate adaptation and resilience building in Amazon protected areas.
Applicatiojns of Allometric principles in animal nutrition researchGanesh Aderao
This document discusses allometric principles in animal nutrition research. It defines allometry as the study of how body size relates to shape, anatomy, physiology and behavior. A key principle is that basal metabolic rate scales with body weight to the 3/4 power, following the surface law. This relates to the fractal-like branching of circulatory networks that efficiently distribute resources. Other relationships discussed include gestation period scaling to the 1/4 power and digestive advantages of larger herbivores due to allometric scaling of gut capacity and retention time.
Applications of allometric principles in animal nutrition nresearchGanesh Aderao
This document discusses allometric principles in animal nutrition research. It defines allometry as the study of how body size relates to shape, anatomy, physiology and behavior. A key principle is that basal metabolic rate scales with body weight to the 3/4 power, following the surface law. This relates to the fractal-like branching of circulatory networks that efficiently distribute resources in a size-independent way. Other relationships discussed include gestation period scaling to the 1/4 power and digestive advantages of larger herbivores allowing them to consume lower quality forage.
This document describes mapping ecological facets across Australia by analyzing the key drivers of ecosystem formation - macroclimate, lithology, landform, and vegetation structural formations. 59 homogeneous bioclimatic regions were mapped based on clustering uncorrelated bioclimatic variables. Lithology and weathering intensity were derived from existing Geoscience Australia data. Landform was characterized through land surface form and topographic moisture potential indicators. Combining these ecosystem drivers with vegetation structural formations data resulted in a continental dataset of 369,439 unique ecological facets at 90m resolution. This ecological facets mapping provides insight into biophysical variation across Australian ecosystems.
This document discusses stromatolites and their importance for understanding microbial processes and environmental change over long time periods. Specifically, it mentions:
1) Stromatolite beds that are up to 600 million years old can provide insights into microbial life and Earth's early environments.
2) The formation of stromatolites depends on the bacterial community composition and environmental factors like the precipitation of calcium carbonate facilitated by microbial extracellular substances.
3) Living stromatolites exist today in locations like Cuatro Ciénegas, Mexico, which can serve as models to study microbial metabolic processes and their responses to environmental changes over time.
This document presents a methodology for mapping global ecosystem vulnerability to climate change and local stressors by integrating assessments of future climate exposure and present ecological integrity (adaptive capacity).
The key findings are:
1) Ecoregions in southern/southeast Asia, western/central Europe, eastern South America, and southern Australia are among the most vulnerable due to low climate stability and degraded integrity.
2) Considering both exposure and integrity reveals different vulnerability patterns than exposure-only assessments.
3) The methodology provides a framework to inform spatially-explicit conservation strategies based on vulnerability levels.
Genomic approaches have revolutionized our understanding of marine ecology in three key ways:
1) They have provided a more unbiased view of marine diversity and evolution by revealing substantial genetic diversity between organisms that were previously thought to be identical based on marker genes alone. This diversity reflects different modes of adaptation to ecological niches.
2) Comparative genomics has shown that horizontal gene transfer, not just vertical inheritance, is a major driver of prokaryotic evolution in the ocean. It allows microbes to rapidly acquire new genes from other domains to adapt to their environment.
3) While genomics provides novel insights into marine organisms' biology and evolution, integrating this reductionist knowledge into holistic concepts that explain
Effects of fishing on the trophic structure of carnivorous
fish assemblages from shallow rocky bottoms of the
Mediterranean Sea and the temperate Atlantic Ocean
Ultrasonic Study on Coconut Water and Sugar Solution Before and After Laser E...iosrjce
IOSR Journal of Applied Physics (IOSR-JAP) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of physics and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in applied physics. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Disturbance of benthic algae by spawning Pacific salmon in Thompson Creek, MIjmkosiara
This is a presentation of my undergraduate senior thesis project at LSSU. This study focused on the effects of spawning Pacific salmon on benthic algal biomass via nutrient enrichment and bioturbation
Estimation of Mineral Content in Vegetable Extraction by Ultrasonic Techniqueinventionjournals
ABSTRACT: Vegetables are very essential for us in improving our nutritional level. They are acting as an herbal medicine in an unfathomable way in our daily life. In my research the select vegetables are Potato, Beetroot which are all rich in vitamin c and Potassium helps to balance fluids and minerals in our body and maintain a normal blood pressure. Estimation of mineral contents and vitamins has been done by measuring the ultrasonic velocity, density, adiabatic compressibility. Further the experimental vales are confirmed by FTIR.
A Trophic State Index for LakesAuthor(s) Robert E. Carlson.docxransayo
A Trophic State Index for Lakes
Author(s): Robert E. Carlson
Reviewed work(s):
Source: Limnology and Oceanography, Vol. 22, No. 2 (Mar., 1977), pp. 361-369
Published by: American Society of Limnology and Oceanography
Stable URL: http://www.jstor.org/stable/2834910 .
Accessed: 27/09/2012 17:20
Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at .
http://www.jstor.org/page/info/about/policies/terms.jsp
.
JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of
content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms
of scholarship. For more information about JSTOR, please contact [email protected]
.
American Society of Limnology and Oceanography is collaborating with JSTOR to digitize, preserve and
extend access to Limnology and Oceanography.
http://www.jstor.org
http://www.jstor.org/action/showPublisher?publisherCode=limnoc
http://www.jstor.org/stable/2834910?origin=JSTOR-pdf
http://www.jstor.org/page/info/about/policies/terms.jsp
A trophic state index for lakes'
Robert E. Carlson2
Limnological Research Center, University of Minnesota, Minneapolis 55455
Abstract
A numerical trophic state index for lakes has been developed that incorporates most
lakes in a scale of 0 to 100. Each major division (10, 20, 30, etc.) represents a doubling
in algal biomass. The index number can be calculated from any of several parameters,
including Secchi disk transparency, chlorophyll, and total phosphorus.
My purpose here is to present a new ap-
proach to the trophic classification of lakes.
This new approach was developed because
of frustration in communicating to the pub-
lic both the current nature or status of lakes
and their future condition after restoration
when the traditional trophic classification
system is used. The system presented here,
termed a trophic state index (TSI), in-
volves new methods both of defining
trophic status and of determining that status
in lakes.
All trophic classification is based on the
division of the trophic continuum, however
this is defined, into a series of classes
termed trophic states. Traditional systems
divide the continuum into three classes:
oligotrophic, mesotrophic, and eutrophic.
There is often no clear delineation of these
divisions. Determinations of trophic state
are made from examination of several di-
verse criteria, such as shape of the oxygen
curve, species composition of the bottom
fauna or of the phytoplankton, concentra-
tions of nutrients, and various measures of
biomass or production. Although each
changes from oligotrophy to eutrophy, the
changes do not occur at sharply defined
places, nor do they all occur at the same
place or at the same rate. Some lakes may
be considered oligotrophic by one criterion
and eutrophic by another; this problem is
1Contribution .
Seagrass under nutrient load and grazingguestb538ca
The document discusses seagrass systems under the pressures of increasing nutrient loads and grazing. It presents the hypothesis that seagrass meadows can shift between different stable states in response to these pressures. Specifically, it hypothesizes that direct nitrogen toxicity, grazing protection from epiphyte overgrowth, and iron deficiency from organic sediment loading can each trigger positive feedback loops pushing the system towards alternative stable states. The document outlines field and mesocosm experiments designed to test these hypotheses by provoking state shifts through nutrient additions, shade, and the removal of grazers. The results will be used to determine thresholds for state shifts and inform seagrass management and restoration efforts.
Earlier collapse of Anthropocene ecosystems driven by multiple faster and noi...Energy for One World
The document discusses how multiple, faster-acting, and noisier drivers may cause ecosystems to collapse more quickly than expected based on single, gradual drivers of change alone. It presents the results of experiments on four ecosystem models - representing fisheries, human populations, forests, and freshwater quality - where collapse times were substantially reduced by adding secondary and tertiary stresses or noise to the primary stressors. The models showed that collapses could occur at lower primary stress levels in the presence of additional drivers or noise. This has implications for better understanding how interacting human and climate pressures could accelerate real-world ecosystem changes.
Affinity: the meaningful trait-based alternative to the obsolete obfuscation ...Lanimal
The document presents an argument that affinity is a superior metric to half-saturation constant (Ks) for describing nutrient uptake rates. It shows that affinity (a) and the Michaelis-Menten constant (Ks) are mathematically related through the maximum uptake rate (Vmax), and that using affinity removes trade-offs seen when using Ks. Plots of uptake rates using the affinity-based and Michaelis-Menten equations show that the affinity formulation is less sensitive to changes in Vmax, improving parameter tuning. Data transformed from a previous study to use affinity rather than Ks shows all data points falling on a straight line with no trade-off, in contrast to the original analysis. The document concludes K
Affinity: the meaningful trait-based alternative to the obsolete obfuscation ...Lanimal
1) The document presents an argument that affinity, represented by the variable "a", is a superior metric to the half-saturation constant "Ks" for modeling nutrient uptake kinetics in aquatic systems. Affinity separates the traits relevant for uptake at high versus low nutrient concentrations in a clearer way.
2) Analysis of multiple data sets shows relationships between maximum uptake rate (Vmax) and affinity, but these relationships do not necessarily indicate a physiological trade-off as relationships between Vmax and Ks had been interpreted. In some cases there was a strong positive correlation between Vmax and affinity.
3) Adopting affinity over Ks allows models to be more easily tuned and better reveals relationships between kinetic parameters,
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This document summarizes a presentation on modeling the effects of trait diversity on phytoplankton communities. It introduces mechanisms for sustaining trait diversity, including trait diffusion and "kill-the-winner," and presents results from a model exploring the short-term and long-term impacts of trait diversity on community productivity and growth rates under different frequencies of disturbance events. The model results show that an intermediate level of trait diversity is optimal and that the optimal level depends on the frequency and intensity of perturbations affecting the community.
This document examines how the assumption of homogeneous vs heterogeneous radioactive contamination in soil/sediment impacts the external radiation dose rates of fauna. It analyzes contamination profiles from sediment samples in Canada and soil samples in Austria involving various radionuclides. Dose conversion coefficients are calculated using a dosimetry model for different organisms, locations within the contaminated media, and exposure scenarios. The results show dose rates can vary by three orders of magnitude depending on the specific situation. The assumption of homogeneous contamination is not always conservative.
This document summarizes a presentation on predicting impacts of climate change on biodiversity. It discusses how climate changes influence biodiversity and the need to predict future impacts to support adaptation. Methods for predicting geographic ranges of species under climate change like bioclimatic and maximum entropy models are introduced. Examples are given of observed climate impacts and predictions of species range shifts and habitat losses. Limitations of these predictive approaches are also acknowledged.
The document summarizes research using a combination of food web and ecosystem modeling to show that impending catastrophic shifts in shallow lake ecosystems are preceded by a destabilization of the aquatic food web. Analysis of trophic interactions revealed that only a few key interactions involving zooplankton, diatoms, and detritus dictate the deterioration of food-web stability. This implies that changes in trophic organization may serve as an empirical indicator of ecosystem resilience and the risk of a regime shift.
Relationship Between Sampling Area, Sampling Size Vs...Jessica Deakin
This document discusses the importance of order in the public realm and how planning, zoning, transects, and urbanism theories help shape our environment. It mentions several authors who have discussed problems with urban design and provided solutions to make the public realm a better place. The document argues that by improving order and the urban framework, cities could become more cohesive in design.
WWF Study: Vulnerability analysis of the amazon biome ClimateCourse
This document provides an analysis of climate vulnerability in the Amazon biome and its protected areas. It begins with an overview of climate change impacts on the region, including increasing temperatures, more frequent droughts and floods, and increased forest fires. It then presents a conceptual framework for assessing climate risks and resilience. The methodology assesses exposure to climate hazards, climate risks to ecosystem services, and factors that build ecosystem resilience. Key findings include increased temperature across the biome, spatially variable drought and flood impacts, and concentration of fires in deforestation fronts. The analysis aims to support climate adaptation and resilience building in Amazon protected areas.
Applicatiojns of Allometric principles in animal nutrition researchGanesh Aderao
This document discusses allometric principles in animal nutrition research. It defines allometry as the study of how body size relates to shape, anatomy, physiology and behavior. A key principle is that basal metabolic rate scales with body weight to the 3/4 power, following the surface law. This relates to the fractal-like branching of circulatory networks that efficiently distribute resources. Other relationships discussed include gestation period scaling to the 1/4 power and digestive advantages of larger herbivores due to allometric scaling of gut capacity and retention time.
Applications of allometric principles in animal nutrition nresearchGanesh Aderao
This document discusses allometric principles in animal nutrition research. It defines allometry as the study of how body size relates to shape, anatomy, physiology and behavior. A key principle is that basal metabolic rate scales with body weight to the 3/4 power, following the surface law. This relates to the fractal-like branching of circulatory networks that efficiently distribute resources in a size-independent way. Other relationships discussed include gestation period scaling to the 1/4 power and digestive advantages of larger herbivores allowing them to consume lower quality forage.
This document describes mapping ecological facets across Australia by analyzing the key drivers of ecosystem formation - macroclimate, lithology, landform, and vegetation structural formations. 59 homogeneous bioclimatic regions were mapped based on clustering uncorrelated bioclimatic variables. Lithology and weathering intensity were derived from existing Geoscience Australia data. Landform was characterized through land surface form and topographic moisture potential indicators. Combining these ecosystem drivers with vegetation structural formations data resulted in a continental dataset of 369,439 unique ecological facets at 90m resolution. This ecological facets mapping provides insight into biophysical variation across Australian ecosystems.
This document discusses stromatolites and their importance for understanding microbial processes and environmental change over long time periods. Specifically, it mentions:
1) Stromatolite beds that are up to 600 million years old can provide insights into microbial life and Earth's early environments.
2) The formation of stromatolites depends on the bacterial community composition and environmental factors like the precipitation of calcium carbonate facilitated by microbial extracellular substances.
3) Living stromatolites exist today in locations like Cuatro Ciénegas, Mexico, which can serve as models to study microbial metabolic processes and their responses to environmental changes over time.
This document presents a methodology for mapping global ecosystem vulnerability to climate change and local stressors by integrating assessments of future climate exposure and present ecological integrity (adaptive capacity).
The key findings are:
1) Ecoregions in southern/southeast Asia, western/central Europe, eastern South America, and southern Australia are among the most vulnerable due to low climate stability and degraded integrity.
2) Considering both exposure and integrity reveals different vulnerability patterns than exposure-only assessments.
3) The methodology provides a framework to inform spatially-explicit conservation strategies based on vulnerability levels.
Genomic approaches have revolutionized our understanding of marine ecology in three key ways:
1) They have provided a more unbiased view of marine diversity and evolution by revealing substantial genetic diversity between organisms that were previously thought to be identical based on marker genes alone. This diversity reflects different modes of adaptation to ecological niches.
2) Comparative genomics has shown that horizontal gene transfer, not just vertical inheritance, is a major driver of prokaryotic evolution in the ocean. It allows microbes to rapidly acquire new genes from other domains to adapt to their environment.
3) While genomics provides novel insights into marine organisms' biology and evolution, integrating this reductionist knowledge into holistic concepts that explain
Effects of fishing on the trophic structure of carnivorous
fish assemblages from shallow rocky bottoms of the
Mediterranean Sea and the temperate Atlantic Ocean
Ultrasonic Study on Coconut Water and Sugar Solution Before and After Laser E...iosrjce
IOSR Journal of Applied Physics (IOSR-JAP) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of physics and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in applied physics. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Disturbance of benthic algae by spawning Pacific salmon in Thompson Creek, MIjmkosiara
This is a presentation of my undergraduate senior thesis project at LSSU. This study focused on the effects of spawning Pacific salmon on benthic algal biomass via nutrient enrichment and bioturbation
Estimation of Mineral Content in Vegetable Extraction by Ultrasonic Techniqueinventionjournals
ABSTRACT: Vegetables are very essential for us in improving our nutritional level. They are acting as an herbal medicine in an unfathomable way in our daily life. In my research the select vegetables are Potato, Beetroot which are all rich in vitamin c and Potassium helps to balance fluids and minerals in our body and maintain a normal blood pressure. Estimation of mineral contents and vitamins has been done by measuring the ultrasonic velocity, density, adiabatic compressibility. Further the experimental vales are confirmed by FTIR.
A Trophic State Index for LakesAuthor(s) Robert E. Carlson.docxransayo
A Trophic State Index for Lakes
Author(s): Robert E. Carlson
Reviewed work(s):
Source: Limnology and Oceanography, Vol. 22, No. 2 (Mar., 1977), pp. 361-369
Published by: American Society of Limnology and Oceanography
Stable URL: http://www.jstor.org/stable/2834910 .
Accessed: 27/09/2012 17:20
Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at .
http://www.jstor.org/page/info/about/policies/terms.jsp
.
JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of
content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms
of scholarship. For more information about JSTOR, please contact [email protected]
.
American Society of Limnology and Oceanography is collaborating with JSTOR to digitize, preserve and
extend access to Limnology and Oceanography.
http://www.jstor.org
http://www.jstor.org/action/showPublisher?publisherCode=limnoc
http://www.jstor.org/stable/2834910?origin=JSTOR-pdf
http://www.jstor.org/page/info/about/policies/terms.jsp
A trophic state index for lakes'
Robert E. Carlson2
Limnological Research Center, University of Minnesota, Minneapolis 55455
Abstract
A numerical trophic state index for lakes has been developed that incorporates most
lakes in a scale of 0 to 100. Each major division (10, 20, 30, etc.) represents a doubling
in algal biomass. The index number can be calculated from any of several parameters,
including Secchi disk transparency, chlorophyll, and total phosphorus.
My purpose here is to present a new ap-
proach to the trophic classification of lakes.
This new approach was developed because
of frustration in communicating to the pub-
lic both the current nature or status of lakes
and their future condition after restoration
when the traditional trophic classification
system is used. The system presented here,
termed a trophic state index (TSI), in-
volves new methods both of defining
trophic status and of determining that status
in lakes.
All trophic classification is based on the
division of the trophic continuum, however
this is defined, into a series of classes
termed trophic states. Traditional systems
divide the continuum into three classes:
oligotrophic, mesotrophic, and eutrophic.
There is often no clear delineation of these
divisions. Determinations of trophic state
are made from examination of several di-
verse criteria, such as shape of the oxygen
curve, species composition of the bottom
fauna or of the phytoplankton, concentra-
tions of nutrients, and various measures of
biomass or production. Although each
changes from oligotrophy to eutrophy, the
changes do not occur at sharply defined
places, nor do they all occur at the same
place or at the same rate. Some lakes may
be considered oligotrophic by one criterion
and eutrophic by another; this problem is
1Contribution .
Seagrass under nutrient load and grazingguestb538ca
The document discusses seagrass systems under the pressures of increasing nutrient loads and grazing. It presents the hypothesis that seagrass meadows can shift between different stable states in response to these pressures. Specifically, it hypothesizes that direct nitrogen toxicity, grazing protection from epiphyte overgrowth, and iron deficiency from organic sediment loading can each trigger positive feedback loops pushing the system towards alternative stable states. The document outlines field and mesocosm experiments designed to test these hypotheses by provoking state shifts through nutrient additions, shade, and the removal of grazers. The results will be used to determine thresholds for state shifts and inform seagrass management and restoration efforts.
Earlier collapse of Anthropocene ecosystems driven by multiple faster and noi...Energy for One World
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1. The document describes a study comparing two models - one using optimal uptake kinetics (SPONGE) and one using Michaelis-Menten kinetics - in simulating a multi-element ecosystem in an iron-enrichment experiment.
2. The SPONGE model allows phytoplankton to dynamically allocate their internal nutrients between uptake sites and enzymes in response to nutrient availability, while the Michaelis-Menten model uses fixed uptake parameters.
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1) Optimal uptake kinetics can explain variations in half-saturation constants (Ks) observed in field experiments better than traditional Michaelis-Menten kinetics. According to optimal uptake kinetics, all phytoplankton acclimate their physiology to ambient nutrient concentrations in the same way.
2) When incorporated into an Earth system climate model, optimal uptake kinetics produced significantly different primary production dynamics compared to Michaelis-Menten kinetics, with more primary production in subtropical gyres and less in upwelling regions.
3) Optimal uptake kinetics provides a more accurate and predictive framework for modeling nutrient uptake and primary production than traditional Michaelis-Menten kinetics, which does not account for phytop
Lan\'s Presentation at the Ocean Sciences Meeting 2010
1. Optimality-based modeling of phytoplankton:
Implications for predictive modeling, interpreting data
and designing experiments
S. Lan Smith
EBCRP, RIGC, JAMSTEC, Yokohama, Japan
Constraints from
Fundamental Processes
Natural Selection
Adaptive Change
Apparent KNO3 (μmol L-1)
Optimally Adapted
Organisms
Physical Environment
S. Lan Smith Ocean Sciences Meeting, Feb. 22-26, 2010
2. Optimality
A result of Natural Selection,
subject to Constraints
Plankton are ideal subjects: Constraints from
short generation times Fundamental Processes
long evolutionary history
Therefore we expect them to Natural Selection
at least approach Optimality, Adaptive Change
which suggests that this concept
should be useful for interpreting
Optimally Adapted
& modeling their behavior. Organisms
Physical Environment
S. Lan Smith p. 2 Ocean Sciences Meeting, Feb. 22-26, 2010
3. Optimality-Based Ideas for Modeling Phytoplankton
Selected Examples Roughly in the Space of Fundamental Processes
Considered in Trade-offs
Light
Photoacclimation
Aquisition
Wirtz & Pahlow (MEPS, 2010)
Pahlow (MEPS, 2005)
Armstrong (DSRII, 2006)
Armstrong (L&O, 1999)
Bruggemann & Kooijman Wirtz (J. Biotech., 2002)
(L&O, 2007) Smith & Yamanaka (L&O, 2007)
Smith et al. (MEPS, 2009)
Nutrient
Uptake
Resistance Merico et al. (Ecol. Modelling, 2009)
to Predators
S. Lan Smith p. 3 Ocean Sciences Meeting, Feb. 22-26, 2010
4. Equations for Rate of Nutrient Uptake
Optimal Uptake (Pahlow, MEPS, 2005) Michaelis-Menten Equation
V0 S Vmax S
vOU = vMM =
Ks + S
A0 √
V0 + 2 V0 S + S
A0 Ks is called the
This is like a MM equation with: Half-Saturation “constant”.
But it varies with:
Nutrient Concentration
A0 √
Ks = V0 + 2 V0 S
A0 Species
Temperature
This predicts that Ks values (as fit to
the MM eqn.) should increase with Affinity & Ks are related:
nutrient concentration. Vmax
A=
Can this explain Ks
the observed pattern?
A is also called a
(Healey. Micrbial Ecol., 1980)
S. Lan Smith p. 4 Ocean Sciences Meeting, Feb. 22-26, 2010
5. What do short-term uptake experiments measure?
If phytoplankton do not have time to acclimate during expts.,
Optimal Uptake (OU) kinetics predicts (Smith et al. MEPS, 2009) for
apparent values of Michaelis-Menten “constants”:
Vmax = √A0Sa/V0 V0
This agrees with observations by
Kudela & Dugdale (DSRII 47, 2000),
1 + √A0Sa/V0
but it needs further testing.
V0 Sa
Ks = √
A0
This agrees with the observed pattern for KNO3
from ship-board expts. (Smith et al. 2009).
It’s all based on a physiological trade-off:
Sa is ambient nutrient
concentration, to which
phytoplankton were
pre-acclimated before
the short-term expts.
Low Nutrient Conc. High Nutrient Conc.
S. Lan Smith p. 5 Ocean Sciences Meeting, Feb. 22-26, 2010
6. Combined Effects of T & Nutrient Concentrations
Growth rates increase exponentially with T
(Eppley. Fish. Bull. 1972; Bissinger et al. L&O 2008).
Max. Uptake Rate, Vmax
For uptake or growth, Vmax is usually assumed
to be independent of nutrient concentration: Temperature
Michaelis-Menten (MM) kinetics.
However, Optimal Upake (OU) kinetics predicts
that Vmax (from short-term expts.) should MM
increase hyperbolically with nutrient conc. OU
(Smith et al. MEPS 2009). Nutrient Conc.
Nutrient Conc.
In the ocean, T and Nutrient Conc. are strongly
(negatively) correlated.
Vmax
Field expts. observe the combined (net) effects.
Assumptions about Uptake Kinetics impact
the interpretation of observations. Temperature
S. Lan Smith p. 6 Ocean Sciences Meeting, Feb. 22-26, 2010
7. Correlation of T & [NO3] in the Surface Ocean
Negative Correlation in General
(e.g., Silio-Calzada et al. Remote Sens. Environ.112, 2008)
Up-welling brings cold, nutrient-rich water
While phytoplankton grow, nutrients are depleted
& at the same time, water is warmed
Here for the data of
Harrison et al (L&O 1996)
*Thanks to G. W. Harrison for
providing the complete data set.
The regression line was
fitted for log [NO3] vs. log T
S. Lan Smith p. 7 Ocean Sciences Meeting, Feb. 22-26, 2010
8. Dependence of Uptake Rate, v, on T & Nutrients
for maximum uptake rate, Vmax as determined by short-term expts.
Assuming Multiplicative Effects
This widely-applied equation is
Michaelis-Menten (MM)
from Goldman and Carpenter
-Ea/RT [NO ] (Limnol. Oceanogr. 19, 1974).
v = Vmax e 3
Ks + [NO3]
Optimal Uptake (OU)
v = V0√[NO3]aA0/V0 e a
-E /RT [NO3]
1 + √[NO3]aA0/V0 √[NO3]aV0/A0 + [NO3]
This ratio determines how Vmax The apparent value of Ks
depends on ambient nutrient depends on ambient nutrient
concentration, [NO3]a. concentration, before
It can be determined separately sampling for expts.
from fits to data: Ks vs. [NO3]a. (Smith et al. MEPS, 2009).
S. Lan Smith p. 8 Ocean Sciences Meeting, Feb. 22-26, 2010
9. Dependence of Vmax on T & Nutrients
for maximum uptake rate, Vmax, as determined by short-term expts,
assuming Multiplicative Effects
Michaelis-Menten (MM) Optimal Uptake (OU)
-Ea/RT √[NO3]aA0/V0 V e-Ea/RT
Vmax = V0 e Vmax = 0
1 + √[NO3]aA0/V0
2 parameters were fitted by regression
to data sets for Vmax, [NO3]a & T,
for each eq., respectively. This ratio was determined
separately, from fits to
V0 potential maximum of Vmax
data for Ks vs. [NO3] as in
Ea Energy of Activation
Smith et al. (MEPS 2009).
S. Lan Smith p. 9 Ocean Sciences Meeting, Feb. 22-26, 2010
10. data of Harrison et al. (L&O 1996) MM OU
T- dependent model 100.0 N &T- dependent model
50
Fits of Arrhenius T- using fit of T vs. [NO3]
50.0
only T- dependent model
Chl-Specific Max. NO3 Uptake Rate (nmol h-1(μg)-1)
dependence, with the Q10 = 1.7 Q10 = 3.4
10
MM- and OU-based as- 5.0
10.0
5.0
sumptions, respectively,
for Vmax 1.0 data 1.0
0.5 fits with obs. 0.5
Data: Chl-specific max.
T & [NO3]
[NO3] uptake rate.
275 285 295 275 285 295
Inferred Q10 is nearly T(K)
100.0
twice as high with the 50
50.0
OU-based assumption.
10 10.0
Residual Square Error: 5.0 5.0
MM OU
9.3 8.5 1.0 T- dependent model 1.0
constant Vmax
0.5 0.5
Fitted values of Ea sig. N &T- dependent model
only N- dependent model
diff. from 0 for both. 10 1 0.1 0.01 0.001 10 1 0.1 0.01 0.001
[NO3] (μmol L-1)
S. Lan Smith p. 10 Ocean Sciences Meeting, Feb. 22-26, 2010
11. data of Kanda et al. (L&O 1985) MM OU
1.0 1.0
Q10 = 1.5 Q10 = 2.7
Chl-Specific Max. NO3 Uptake Rate (nmol h-1 (μg chl)-1 )
Fits of Arrhenius T- depen-
dence, with the MM- and 0.5 0.5
OU-based assumptions, re-
spectively, for Vmax
Data: Chl-specific max. N &T- dependent model
0.1 0.1
T- dependent model
[NO3] uptake rate. using fit of T vs. [NO3]
using fit of [NO3] vs. T
only T- dependent model
Inferred Q10 is nearly 285 290 295 300 285 290 295 300
T(K)
twice as high with the OU-
1.0 1.0
based assumption.
Residual Square Error: 0.5 0.5
MM OU
0.82 0.34
Fitted values of Ea sig. diff. data
0.1 fits with obs. 0.1 N &T- dependent model
from 0 for both. T & [NO3]
using fit of T vs. [NO3]
only N- dependent model
0.1 0.01 0.001 0.1 0.01 0.001
[NO3] (μmol L-1)
S. Lan Smith p. 11 Ocean Sciences Meeting, Feb. 22-26, 2010
12. Conclusions
Optimality-based ideas imply different Interpretations of Observations.
Specifically for Combined Effects of T & Concentration on Uptake
Estimated Q10’s are 2X greater assuming OU vs. MM kinetics.
Caveat: The observed Vmax were Chl-specific
Chl:N ratios tend to be greater under nutrient-rich conditions,
which should under-estimate N-specific rates at high N (low T)
Therefore my analysis probably over-estimates Q10’s
for both MM- and OU- kinetics
Yet even with biomass-specific Vmax, OU would yield higher Q10’s
because of the strong negative correlation of T & [NO3}
Significant Uncertainties remain about T-dependence & uptake kinetics
We need more controlled experiments &
field observations of biomass-specific rates
S. Lan Smith p. 12 Ocean Sciences Meeting, Feb. 22-26, 2010