Zooplankton distribution and seasonal successionAl Nahian Avro
The seasonal distribution of the major components of the zooplankton community, protozooplankton, copepods and cladocerans, along a eutrophication gradient were examined in order to establish if eutrophication through increases in phytoplankton biomass and productivity has an impact on biomass and composition of the zooplankton community
The plankton is divisible into two main groups, the phytoplankton and the zooplankton. The primary productivity which we discussed in chapter 10 is primarily the functional aspect of phytoplankton - the other chlorophyll bearing organisms are also to be included, but in most water bodies such as the culture pond an index of primary productivity could be obtained by the mass or number of phytoplankton in a unit volume of water
Freshwater ecosystems are a subset of Earth's aquatic ecosystems. They include lakes and ponds, rivers, streams and springs, and wetlands. They can be contrasted with marine ecosystems, which have a larger salt content. This module explains the characteristics of aquatic ecosystems-freshwater ones.
Zooplankton distribution and seasonal successionAl Nahian Avro
The seasonal distribution of the major components of the zooplankton community, protozooplankton, copepods and cladocerans, along a eutrophication gradient were examined in order to establish if eutrophication through increases in phytoplankton biomass and productivity has an impact on biomass and composition of the zooplankton community
The plankton is divisible into two main groups, the phytoplankton and the zooplankton. The primary productivity which we discussed in chapter 10 is primarily the functional aspect of phytoplankton - the other chlorophyll bearing organisms are also to be included, but in most water bodies such as the culture pond an index of primary productivity could be obtained by the mass or number of phytoplankton in a unit volume of water
Freshwater ecosystems are a subset of Earth's aquatic ecosystems. They include lakes and ponds, rivers, streams and springs, and wetlands. They can be contrasted with marine ecosystems, which have a larger salt content. This module explains the characteristics of aquatic ecosystems-freshwater ones.
Generalized and specific definition of pond and the types relating their size, use, construction method were illustrated. Besides the culture system of fish and aquatic organisms and their types were also described.
At what age does a fish attain a maturity
What is the perfect catchable or mark able size of the fish
It helps to calculate the life span and longevity of fish
It enables to estimate and compare growth rates of fish in different waters.
Good or bad growth can point out the suitability for rearing and stocking purposes
The timing of spawning migration of given species can be worked out .
fish population dynamics, Population structureDegonto Islam
Estimation of fish population dynamics are often based on age structures. Understanding past
population structure is of interest to evolutionary biologists because it can reveal when migration
regimes changed in natural populations, thereby pointing to potential environmental factors such as
climate changes as driving evolutionary forces. Characterizing the structure of extent populations is also
key to conservation genetics as translocation or reintroduction decisions must preserve evolutionary
stable units. Finally, population structure has important biomedical consequences either when a number
of subpopulation groups is locally adapted to particular environmental conditions (and maladapted
when exposed to new environments) or represents a confounding factor in the study of the statistical
association between genetic variants and phenotyp
Nutritional requirement of cultivable fin fish: larvae, juveniles and adultsDebiprasad1997
Fish is among the healthiest foods on the planet. It is loaded with important nutrients, such as protein and vitamin D. Fish is also the world's best source of omega-3 fatty acids, which are incredibly important for human body and brain.
Manufactured feeds are an important part of modern commercial aquaculture, providing the balanced nutrition needed by farmed fish.
In the development of modern aquaculture, starting in the 1970s, fishmeal and fish oil were key components of the feeds for these species. They are combined with other ingredients such as vegetable proteins, cereal grains, vitamins and minerals and formed into feed pellets.
The global supply of fish meal and fish oil is finite and fully utilized. Alternative or nontraditional feedstuffs may differ in terms of taste, smell, texture, and color, as well as nutrient composition, from the traditional feedstuffs, which are produced largely from the natural prey of the fish being raised. Alternative feedstuffs may also contain compounds and antinutritional factors that affect digestive or sensory physiology.
Another important area of fish nutrition for the next 20 years will be larval fish nutrition. Currently, the cost and difficulty of rearing a great number of species from the first feeding to the juvenile stage are the most severe bottlenecks to the development of aquaculture production of nontraditional species.
Generalized and specific definition of pond and the types relating their size, use, construction method were illustrated. Besides the culture system of fish and aquatic organisms and their types were also described.
At what age does a fish attain a maturity
What is the perfect catchable or mark able size of the fish
It helps to calculate the life span and longevity of fish
It enables to estimate and compare growth rates of fish in different waters.
Good or bad growth can point out the suitability for rearing and stocking purposes
The timing of spawning migration of given species can be worked out .
fish population dynamics, Population structureDegonto Islam
Estimation of fish population dynamics are often based on age structures. Understanding past
population structure is of interest to evolutionary biologists because it can reveal when migration
regimes changed in natural populations, thereby pointing to potential environmental factors such as
climate changes as driving evolutionary forces. Characterizing the structure of extent populations is also
key to conservation genetics as translocation or reintroduction decisions must preserve evolutionary
stable units. Finally, population structure has important biomedical consequences either when a number
of subpopulation groups is locally adapted to particular environmental conditions (and maladapted
when exposed to new environments) or represents a confounding factor in the study of the statistical
association between genetic variants and phenotyp
Nutritional requirement of cultivable fin fish: larvae, juveniles and adultsDebiprasad1997
Fish is among the healthiest foods on the planet. It is loaded with important nutrients, such as protein and vitamin D. Fish is also the world's best source of omega-3 fatty acids, which are incredibly important for human body and brain.
Manufactured feeds are an important part of modern commercial aquaculture, providing the balanced nutrition needed by farmed fish.
In the development of modern aquaculture, starting in the 1970s, fishmeal and fish oil were key components of the feeds for these species. They are combined with other ingredients such as vegetable proteins, cereal grains, vitamins and minerals and formed into feed pellets.
The global supply of fish meal and fish oil is finite and fully utilized. Alternative or nontraditional feedstuffs may differ in terms of taste, smell, texture, and color, as well as nutrient composition, from the traditional feedstuffs, which are produced largely from the natural prey of the fish being raised. Alternative feedstuffs may also contain compounds and antinutritional factors that affect digestive or sensory physiology.
Another important area of fish nutrition for the next 20 years will be larval fish nutrition. Currently, the cost and difficulty of rearing a great number of species from the first feeding to the juvenile stage are the most severe bottlenecks to the development of aquaculture production of nontraditional species.
Biological and chemical oceanography.Chemical Oceanography is fundamentally interdisciplinary. The chemistry of the ocean is closely tied to ocean circulation, climate, the plants and animals that live in the ocean, and the exchange of material with the atmosphere, cryosphere, continents, and mantle
Marine biology Marine organisms that live on or inside the bottom, different types of beaches, and biodiversity in these different types of beaches
#Environment
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
This presentation explores a brief idea about the structural and functional attributes of nucleotides, the structure and function of genetic materials along with the impact of UV rays and pH upon them.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
2. CONTENTS
INTRODUCTION
TYPES OF BENTHOS
BY SUBSTRATUM
BY SIZE
BY TYPE
BY LOCATION
BY MOBILITY
ADVANTAGES OF BENTHOS
ROLES OF BENTHOS IN THE AQUATIC
ECOSYSTEM
IMPACTS OF TRAWLING ON THE SEABED
& BENTHIC COMMUNITIES
CONCLUSION
2
3. INTRODUCTION
Benthos is the community of organisms that live on, in or near the
seabed, also known as the benthic zone. This community lives in or
near marine sedimentary environments, from tidal pools along the
foreshore, out to the continental shelf and then down to the abyssal
depths. Many organisms adapted to deep water pressure can not
survive in the upper parts of the water column. The pressure
difference can be very significant.
The term benthos is coined by Haeckel in 1891, comes
from the Greek, meaning “depths of the sea” and refers collectively
to organisms which live on, in or near the bottom of the sea. Many
organisms adapted to deep water pressure, can not survive in the
upper parts of the water column.
3
4. TYPES OF BENTHOS
Benthic community is diversified from species including plants,
animals and bacteria from diverse range of food chain. Benthic
organisms can be classified on the different basis.
By substratum :-
a. Infauna : Organisms that live in the sediment, e.g. worms,
clams etc.
4
Common fire worm Giant clam
5. b. Epifauna : Organisms which either attach to the bottom or
susbstrate, e.g. sponge, oysters, mussels, starfish etc.
5
Star fish Pearl oyster
6. By size :-
a. Macrobenthos : Macrobenthos are comparatively large
organisms living on or near in the
bottom of water, e.g. Seagrass,
Echinoderms, sponges, crustaceans etc.
6
Sponge Seagrass
7. b. Meiobenthos : Meiobenthos are the organisms that live in
bottom of water of both freshwater and marine
water ecosystem, e.g. Gastrotricha, Water bears
etc.
7Gastrotricha Water bear
8. c. Microbenthos : Microbenthos is the community of species
living in, on or near the bottom of water
body, e.g. Amoeba, flagella, bacteria,
diatoms etc.
8Amoeba Diatoms
9. By type :-
a. Zoobenthos : The benthos those are animal origin called
zoobenthos, e.g. Starfish, Oysters, Mussels
etc.
9
Mussels Edible oyster
10. b. Phytobenthos : Benthos those are plant origin are called
phytobenthos, e.g. Seagrass, seaweed etc.
10
Seagrass Seaweed
11. By location :-
a. Endobenthos : Endobenthos use bottom of the sediments as
their habitat, e.g. Sea pen, Sand dollar etc.
11Sea pen Sand dollar
12. b. Epibenthos : Epibenthos use top of the sediments as their
habitats, e.g. Sea cucumber, Sea snail etc.
12Sea cucumber Sea snail
13. c. Hyperbenthos : Hyperbenthos just live floating above the
sediments, e.g. Rock cod.
13Rock cod
14. By mobility :-
a. Sessible benthos : Sessible benthos do not have any mobility,
attached or fixed with the substratum, e.g.
Benthic algae, Sea grasses, Corals etc.
14Benthic grass Coral
15. b. Vagrant benthos : Vagrant benthos are those that have
locomotory powers and either they can
move rapidly or slowly, e.g. crabs, stingray
etc.
15Crab Sting ray
16. ADVANTAGES OF BENTHOS
Benthos are good indicators of localized conditions of water
quality due to their limited mobility.
They are sensitive to environmental impacts from both point and
non-point source of pollution.
They integrate the effects of short term environmental
variations.
They serve as the primary food source for many species of
commercially and recreationally important fishes.
When monitored together with relevant chemical/physical
parameters, benthos communities can be used to identify
sources of impairment.
They are holistic indicators of overall water quality.
16
17. ROLES OF BENTHOS IN THE
AQUATIC ECOSYSTEM
The benthic organisms are most versatile on the coastal zone
where the fish and other aquatic animals have multifaceted to a
vast array of effects. Shallow maritime biological community is
highly affected by the gathering of human and environmental
changes. Benthic invertebrates functionally play big roles in fish
production.
Some important role of benthos is given below :-
Essential for ecosystem : Benthos plays a big role in ecosystem
by decomposition.
Nutrition : Benthic invertebrates release good
amount of nutrients naturally by
their feeding activities, excretion
and burrowing into sediments.
17
18. Remineralization : Benthos filter large amount of water and pump
into their bodies. By this activity sediment
and organic matters washed out that
clean the water. The unused organic matter
felled out on the bottom of the sea bed. That
is called remineralized matter.
Food source : Many fishes feed on small to medium size
benthic organism that live on sea floor.
Vital saltwater fish community like
Haddock, catfish as well as many
freshwater fish eats benthos.
Increase oxygen : Many of benthic animals move actively on the
bottom and mix the sediments around there
and improve the oxygen concentration which
help in higher production overall organism.
18
19. IMPACTS OF TRAWLING ON THE
SEABED & BENTHIC COMMUNITIES
Destruction or damage to structurally complex habitats
Reduction in bioturbation
Death and damage to infauna and epifauna
Reduction in benthic species diversity
Re-suspension of sediments
Attraction of scavengers
19
20. CONCLUSION
Benthos is the community of organisms that live on, in or near the
seabed. This community lives in or near sedimentary
environments, from tidal pools along the foreshore, out to the
continental shelf and then down to the abyssal depths.
Although most of the benthos are very small in size, but they play
important role in aquatic ecosystem as they act as bio-indicators,
are important as nutrient in different trophic levels of food chain
& food-web & have role in nutrient & mineral cycling as they act
as decomposers. So that they represent all the trophic levels as
producer, consumer as well as decomposers.
20