marine food web

marine food web

1. MARINE FOOD WEB BY, ARABINDA PAL MARINE BIOTECHNOLOGY PART-I 1

2. 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

3. TROPHIC LEVEL A position in a food chain or Ecological Pyramid occupied by a group of organisms with similar feeding mode. 3

4. 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

5. CONNECTANCE The complexity of food web can vary greatly & express this complexity by a measure called connectance of the food web.   If there is species no. is ‘n’, the potential no. of interspecific interactions   5

6. TYPES OF FOOD WEB Food webs are of three types- Connectedness or topological or static food web Energy flow or biogenetic food web Functional or interactional food web 6

7. DIFFERENT TROPHIC LEVELS OF MARINE PLANKTONIC FOOD WEB Producer – The p rimary 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. 7

8. Zooplankton – They are primary consumer. Phytoplankton are eaten by the primary consumer. They include- s ingle cell ciliates Copepods Shrimp Larvae of mollusk, etc. Small predators - They are the secondary consumers. They are feed on the zooplanktons. They includes- Krill Some small fish such as herring, sardine, etc. 8

9. Top Predators - They are eat both secondary predators and zooplanktons.They includes- Cephalods (octopus) Large fish such as tuna, shark etc. Marine mammals such as Whales, seals, dolphins etc. 9

10. Marine p lanktonic F ood W eb 10

11. 11 Types of Marine Food Chain According to John Ryther 3 types of food chain found in marine ecosystem … Oceanic type Continental shelf type Upwelling zone type

12. 12 Oceanic Type Oceanic system have five-e trophic levels with a low production of about 50 g C m -2 y -1 .

13. 13 Continental Shelf Type This type has 3 trophic levels and the primary production is about 100 g C m -2 y -1 .

14. 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 -2 y -1 .

15. 15 EFFECT OF HUMAN IN MARINE ECOSYSTEM AND FOOD WEB Extreme fisheries Ocean pollution Acidification

16. 16 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. D ue 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. 17 ACKNOWLEDGEMENT…. T, K, Saha . Ecology and E nvironmental Biology Jeffrey S. Levinton , Marine Biology Ivan Valiela , Marine Ecological process Wikipedia

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