1. Eutrophication A Review of Its Process and Ecological Impacts
Yang Zhang
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2. Introduction
Previously,
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3. In the past few decades,
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4. Definition:
The enrichment of water by nutrients, stimulating and array of symptomatic changes including increased production of algae and/or high plants, which can adversely affect the diversity of the biological system, the quality of the water, and the uses to which the water may be put.
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5. Topics of Discussion Nutrient limitation •CAUSES • PROCESS
Nutrient input sources
Nutrient loading
• PROCESS
•ASSOCIATED PHYTOPLANKTONS
•CONSEQUENCES
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6. Causes of Eutrophication
Anthropogenic inputs
N, P nutrient enrichment
Algae bloom
Allochthonous C
Autochthonous C
Organic matter loading
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7. Nutrient Limitation Basic elements: Macronutrients:
C, H, O
Macronutrients:
Ca, Mg, K, P, N, S, Fe, Si
Trace elements:
B, Cl, Co, Cu, Mn, Mu, Zn, vitamin
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8. Nitrogen Phosphorus and Are the key nutrients causing
eutrophication problems
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9.                                                                            
Note the bright green color caused by algae stimulated by the experimental addition of phosphorus for the 26th consecutive year. Lake 305 in the background is unfertilized
                                                                           
Blue green "algae" (Cyanobacteria) were able to "fix" nitrogen that had diffused naturally into the lake from the air, thereby making the nitrogen available for supporting algal growth.
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10. Nitrogen enrichment not only causes algae blooms, but also…
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11. Nitrogen formulation can regulate the cell size distribution of phytoplankton communities
Smaller species have a higher preference for ammonia uptake over nitrate than larger species
Larger species have the capacity for more internal storage of nutrients and become dominant in fluctuating nutrient regimes
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12. Nutrient Input Sources
Nonpoint sources
•Run off from farmlands
• Run off from lawns and paved areas
• Industry
• Waste water treatment plants
Point sources
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13. Nutrient Loading P Naturally, --Anthropogenically, Exists as phosphate
Sorbed to soil particles
Liberated by weathering
Not easily leached out
--Anthropogenically,
Human-caused changes in the global P budget have caused P to accumulate in upland soils, and increasing soil P levels elevate the potential P runoff to aquatic ecosystems.
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14. N Naturally, Anthropogenically,
Many forms of nitrogen, especially fertilizers, are released to the environment
Easily leached out of the upper soil layers by rainfall
Nitrogen fixation
Nitrification
Denitrification N2
NH4+
NO3- N2
oxic
anoxic
Cell mass
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15. Process of Eutrophication
High nutrient release
Anaerobic benthic
High algal photosynthesis
High organic matter
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16. Algae Associated with Eutrophication
“Red tides”
Red algae
Furcellaria
Phycodrys
“Green tides”
--Green algae
Chlorophytes
Cryptophytes
Cyanobacteria
Diatoms
Dinoflagellates
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21. Consequences of Eutrophication
Destroy food chain
Algae bloom algae species change
block sunlight
loss of available food
Underwater grasses die
Herbivorous die displacement of fish
and crabs
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22. Anoxic water kills fish and crabs
High nutrient release
Anaerobic benthic
High algal photosynthesis
High organic matter
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23. Produce toxic chemicals
Toxins produced by cyanobacteria can not be removed by conventional water treatment processes
Causing many chronic health problems in humans.
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24. Thank you!
                                          
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