Biological benthos presentation by hafez ahmad

benthic organism.

1. Benthos Hafez ahmad COURSE: Biological Oceanography ID: 15207021 INSTITUTE OF MARINE SCIENCES AND FISHERIES UNIVERSITY OF CHITTAGONG

2. benthos Benthos is the community of organisms that live on, in, or near the seabed. Benthos such as Worms , clams ,crabs, lobsters ,sponge , snails , kelp etc. Benthic life

3. Benthic community The Benthic Community is made up of organisms that live in and on the bottom of the ocean floor. Benthic communities can be found in rocky shores, sediment-covered shores, kelp forest, and coral reef and deep sea hydrothermal vent . 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.

4. Major c benthos Benthic organisms include members of the following kingdoms and phyla : Kingdom : Monera:- cyanobacteria or blue-green algae. Kingdom: Protista a. Phylum : Chrysophyta: -benthic diatom b. Phylum Protozoa:- foraminifera 3. Kingdom : Plantae: a. Phylum : Chlorophyta:-green seaweeds b. Phylum : brown algae:-large kelps c. Phylum Rhodophyta: red algae d. Phylum Tracheophyta :- eelgrass 4.Kingdom : Animalia a. Phylum Porifera : sponges b.Phylum Arthropoda: crab c. Phylum Cnidaria ( Coelenterata):- coral ,sea anemone d . Phylum Mollusca : bivalves(mussels, Single-shelled mollusks(limpets) e. Phylum Echinodermata: Sea cucumbers, sea urchins ,starfish. f . Phylum Chordata: sea squid, bottom dwelling fish g. Phylum Annelida: tube worms h .Phylum Platyhelminthes : flatworms

5. Classification of Benthos 1.Infauna : filter: clam ,deposit: crab ,phy: macroalgae 2.epi: 3:nektobenthos: octopus 4:mega: 5:macro: ostracod, polychaete worm 6.Micro:flagellates 7.meio: nematodes

6. nektobenthos Filter feeder Deposit feeder flagellate meiofauna mega

7. Benthic zone Benthic habitats cover about 70% of the earth surface. The benthic zone is the ecological region at the lowest level of a body of water such as an ocean or a lake, including the sediment surface and some sub-surface layers. The benthic region of the ocean begins at the shore line (intertidal or eulittoral zone) and extends downward along the surface of the continental shelf out to sea.

8. Distribution The distribution of oceanic benthic biomass (in grams per square meter) shows that the ocean’s lowest biomass is beneath the centers of subtropical gyres and the highest values are in high-latitude continental shelf areas. the greatest animal diversity is in the lower (tropical) latitudes , while the diversity of algae is greater in the middle latitudes , probably because of better availability of nutrients

9. Benthic Ecosystem

10. Factors affecting the abundance of benthic organisms Biotic factors Abiotic factor a. Competition for space and food a . Salinity b. Predation b. Temperature c. Reproduction c. Air and light exposure d. Substrate settlement preference d. Tidal flow e. Osmoregulation e. Waves and current action f. Substrate g. Dissolved O2 h. natural disasters

11. Seafloor characteristics Environmental characteristics 1.Light 2. Temperature 3. Salinity 4. Pressure 5.Density

12. Marine Sediment

13. Cosmogenous sediment Hydrogenous sediment Biogenous sediment Terrigenous sediment

14. Sediment distribution

15. Importance of benthos 1: primary production. 2: bio indicator. 3:controlling oxygen availability. 4: nutrients cycling. 5:Critical role in the functioning of ecosystem . 6:Major link in the food chain. 7:Pump large amount f water through their bodies. 8:Clean water. 9:Role in sediment recycling. 10:food source for bottom-feeding fish , invertebrates, and birds . 11: integrates within the food web, over time, and over a number of environmental variables . 12: Benthic responses to pollution controls.

16. Biological indicator So benthos are good bioindicator because They are very sensitive to pollution . Benthos can be monitored for changes(morphological ,physiological or behavioral that may indicate a problem within their ecosystem. 3. Abundance ,biodiversity depends on substratum and water quality. 4.Act as scavenger . 5.Role of filter feeder and deposit feeder. Bioindicator are the organisms that indicate or monitor the health of the environment .A good bioindicator will indicate the presence of pollutant and also attempt to provide additional information about the amount and intensity of the exposure. a b

17. Any questions?