Eutrophication food chain in aquatic ecosystem

MICROBIOLOGY

1. Eutrophication ; f ood chain in aquatic ecosystems PRESENTED BY: Mousami Jaria St. George College of Management and Science MSc Microbiology Semester 2

2. INTRODUCTION Eutrophication means when a waterbody is oversupplied with minerals and nutrients which induces excessive growth of algae . It results in oxygen depletion of the water body eg ; algal bloom, increase of phytoplankton etc. It is induced by the discharge of nitrate or phosphorus.

3. Phosphate containing detergents, fertilizers or sewage, domestic run outs into aquatic ecosystem. Most lakes follow the path of eutrophication over geologic time in. When the addition of organic matter proceeds at an increasing rate ,the process of eutrophication accelarates . Eutrophication is a process and a trophic state. The key element is change.

4. Upwelling systems cycle through phases of increased nutrient availability, high primary and secondary productivity,and often oxygen depletion in the lower water coloumn .

5. TYPES NATURAL EUTROPHICATION : Caused by natural process of nature not interfered by human activities. Takes many years to affect whole water bodies. Water bodies near industrial or human habitat are affected by such source of eutrophication .

6. CULTURAL EUTROPHICATION : It speeds up natural eutrophication because of human activities. Results in algal bloom. Reduces amount of dissolved oxygen in water leading to plant and animal death.

7. EFFECTS Oxygen depletion or hypoxia is a common effect of eutrophication in water. The direct effect is that it kills fish specially those which require high levels of oxygen. The algal blooms prevents sunlight from entering into water thereby killing plants and animals underneath.

8. DIED FISHES DUE TO EUTROPHIC WATER

9. ALGAL BLOOM IN WATER

10. FOOD CHAIN IN AQUATIC ECOSYSTEM In lakes the food chain includes : BACTERIA PHYTOPLANKTON PROTOZOA MICRO and MACROZOOPLANKTON And the trophic links between them. Plankton food chain in lakes is affected in a predictable manner by eutrophication . Phytoplankton biomass becomes relatively greater while macrozooplankton biomass declines.

11. The relative biomass of protozoa may also increase. Food chain function also is affected : ecological transfer efficiency is lowest in ultraoligotrophic lakes and hypereutrophic lakes and highest in mesotrophic lakes. In ultra oligotrophic lakes co- occurance of picoplankton with copepods that cannot directly graze such small particles results in long, energitically inefficient foodwebs .

12. In hypereutrophic lakes similar food web occurs owing to co occurance of cyanobacteria and small macrozooplankton . The dominance of cyanobacteria in these lakes can be linked to enrichment with nutrients (nitrogen, phosphorus), while zooplankton attributes to intense fish predation. Changes in plankton food chain structure and function can be reversed if nutrient loads are substantially reduced.

13. Effect of nutrient loadings are different in freshwater and marine ecosystem. In ultraoligotrophic and hypereurotrophic lakes the size or palatability of phytoplankton disrupt the flux of energythroughout the food chain by inhibiting large zooplankton grazing. In mesotrophic lakes short food chains efficiently transfer energy from primary producers to fish. Marine systems display more complex planktonic food chains

14. The main pathway of carbon flow from cyanobacteria to zooplankon is from detritus and dissolved organic matter ( microbial loop). Cyanobacteria may be used via microbial pool. The carbon transfer to fish reflects the activity in grazing food chain, because unsaturated fatty acids are known to rapidly decompose

15. PREVENTION Shifts in phytoplankton and zooplankton communities. Shifts in foodwebs as they support loss of biodiversity Change in trophic interaction and changes in ecosystem functions and biogeochemical processes.

16. CONCLUSION Eutophication is a major problem in aquatic ecosystems that is driven primarily by sulphur and phosphorus loading. Eutrophication can result in increased incidence and significance of algal bloom , anoxic conditions, ocean acidification and altered plant species diversity. The effects are production of toxins that affect human and animal health, fish kills that negatively impact the food security, food web

17. disruption and dead zones that disrupt ecosystem. The disruptions in ecosystem functions negative impact to tourism industry with economic consequences To reduce the impact of eutrophication , leaching should be reduced from agriculturalactivities , growing perrenial plants, reduced applicatin of fertilizers, planting winter cover crops to reduce nutrient leaching.

18. Others include vehicle efficiency advancements, enhanced removal of Nox from exhaust, stricter emission standards etc.

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