marine food web

MARINE FOOD WEB

BY,

ARABINDA PAL

MARINE BIOTECHNOLOGY

PART-I 1

INTRODUCTION

In nature food chains are not isolated. Most

ecosystem contain several inter connected

food chains which forms a food web.

Food web is the feeding relationship in an

ecosystem.

Food chain is a linear sequence of feeding

relationship, where as food web is the

complex relation between different food chain

2

TROPHIC LEVEL

A position in a food chain or Ecological Pyramid occupied

by a group of organisms with similar feeding mode.

3

ENERGY FLOW

Sun is the all source of energy. Producer take light

energy from the sun and converted it into the

chemical energy. When primary consumer feed on the

producer energy transfer occur.

4

CONNECTANCE

The complexity of food web can vary greatly & express

this complexity by a measure called connectance of

the food web.

𝑐𝑜𝑛𝑛𝑒𝑐𝑡𝑎𝑛𝑐𝑒 =𝑎𝑐𝑡𝑢𝑎𝑙 𝑛𝑜. 𝑜𝑓 𝑖𝑛𝑡𝑒𝑟 𝑠𝑝𝑒𝑐𝑖𝑓𝑖𝑐 𝑖𝑛𝑡𝑒𝑟𝑎𝑐𝑡𝑖𝑜𝑛𝑠

𝑝𝑜𝑡𝑒𝑛𝑡𝑖𝑎𝑙 𝑛𝑜. 𝑜𝑓 𝑖𝑛𝑡𝑒𝑟𝑠𝑝𝑒𝑐𝑖𝑓𝑖𝑐 𝑖𝑛𝑡𝑒𝑟𝑎𝑛𝑡𝑖𝑜𝑛𝑠

If there is species no. is ‘n’, the potential no. of

interspecific interactions

=𝑛 𝑛 − 1

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TYPES OF FOOD WEB

Food webs are of three types-

a.Connectedness or topological or static

food web

b.Energy flow or biogenetic food web

c.Functional or interactional food web

6

DIFFERENT TROPHIC LEVELS OF

MARINE PLANKTONIC FOOD WEB

Producer – The primary producer are mainly

phytoplankton. They include single cell dinoflagellates,

diatoms, cyanobacteria and some algae.

They absorb the light energy from the sun and

converted into the chemical energy in the form of

carbohydrate

They account for the 95% of the oceanic productivity

and the half of the earth productivity.

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Zooplankton – They are primary consumer.

Phytoplankton are eaten by the primary consumer.

They include-

o single cell ciliates

o Copepods

o Shrimp

o Larvae of mollusk, etc.

Small predators - They are the secondary consumers.

They are feed on the zooplanktons. They includes-

oKrill

o Some small fish such as herring,

sardine, etc.8

Top Predators - They are eat both secondary predators

and zooplanktons.They includes-

oCephalods(octopus)

o Large fish such as tuna, shark etc.

oMarine mammals such as Whales, seals,

dolphins etc.

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Marine planktonic Food Web10

11

Types of Marine Food Chain

According to John Ryther 3 types of food chain

found in marine ecosystem …

I. Oceanic type

II.Continental shelf type

III.Upwelling zone type

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Oceanic Type

Oceanic system have five-e trophic levels with a low

production of about 50 g C m-2 y-1.

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Continental Shelf Type

This type has 3 trophic levels and the primary production

is about 100 g C m-2y-1.

14

Upwelling Zone Type

This type has only two trophic levels. Upwelling provided

higher and more continuous nutrient supply leading to a

primary production of about 300 g C m-2y-1.

15

EFFECT OF HUMAN IN MARINE

ECOSYSTEM AND FOOD WEB

oExtreme fisheries

oOcean pollution

oAcidification

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CONCLUSION

Marine phytoplankton produced half of the world

primary productivity. The different variation of

the marine food web shows the wide diversity of

marine ecosystem. Due to the extreme fisheries,

pollution the marine ecosystem very much

affected. Many species are extinct due to this

which destroy the equilibrium of the food web.

17

ACKNOWLEDGEMENT….

T, K, Saha. Ecology and Environmental Biology

Jeffrey S. Levinton, Marine Biology

Ivan Valiela, Marine Ecological process

Wikipedia

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