Benthos - types and their role in ecosystem

Benthos, the benthic organism which is play a big role in ecosystem. There has a brief description on the type of this organisms and roles.

1. BENTHOS AND THEIR ROLE IN AQUATIC ECOSYSTEM Submitted by - ANURADHA NASKAR ( M.F.Sc . II Sem.) DEPARTMENT OF ZOOLOGY AND APPLIED AQUACULTURE BARKATULLAH UNIVERSITY, BHOPAL MADHYA PRADESH, 462026 1

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 : O rganisms 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 : M acrobenthos 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. 7 Gastrotricha 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. 8 Amoeba 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. 11 Sea pen Sand dollar

12. b. Epibenthos : Epibenthos use top of the sediments as their habitats, e.g. Sea cucumber, Sea snail etc. 12 Sea cucumber Sea snail

13. c. Hyperbenthos : Hyperbenthos just live floating above the sediments, e.g. Rock cod. 13 Rock 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. 14 Benthic 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. 15 Crab 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. They can be used to asses nonchemical impacts to the aquatic habitat. 16

17. ROLES OF B ENTHOS 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

21. Thank You…