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:
1. Kingdom: Monera:- cyanobacteria or blue-green algae.
2. 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. Benthos
Substratum
Nektobentho
s)
Infauna Epifuana
size
mega
Meio
(10 – 0.1mm)
Macro(>10mm) Micro(<0.1mm
feeding
Filter Deposit
type
Zoobenthos Phytobenthos
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
Marine sediment
lithogenous
e.g:rock
fragments,clay,quartz,volcanic
ash,
biogenous
Calcareous ooze, siliceous ooze
hydrogenous
Manganese nodules, metal
sulfide
cosmogenous
Meteorites, space dust

13. Cosmogenous sedimentHydrogenous sediment
Biogenous sedimentTerrigenous 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
1. They are very sensitive to pollution .
2. 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?