Term
| eutrophic lakes-general characteristics |
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Definition
-often small, shallow
-high nutrient concentration
-high productivity |
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Term
| is eutrophication a natural process? |
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Definition
| yes, overtime all lakes accumulate sediments, nutrients (they become enriched) |
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Term
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Definition
change in lake trophic status overtime
- oligotrophic --> eutrophic overtime (natural process)
-Often it takes hundreds of years for the succession of life in a lake to be completed |
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Term
| cultural eutrophication describes a rapid change in trophic state due to what (what happens specifically) |
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Definition
| increased nutrient loading caused by human activity - algal blooms and/or extensive macrophyte growth occurs |
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Term
in lecture he showed us a graph of increased nutrient loading and contribution to primary the following points were made (fill in the blank)
1. __ in overall productivity as nutrients increase
2. shit toward dominance of _________ and emergent/floating leaved macrophytes
3. shift from nutrient limitation to ___ limitation |
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Definition
1.increase
2.phytoplankton
3light |
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Term
| list 4 problems with eutrophication |
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Definition
1. taste and odor of lake
2. interferene (thick macrophyte beds)
3. fish kills after algal blooms
4. species loss |
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Term
| what are 2 sources of phosphorus that drive eutrophication (be able to explain these) |
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Definition
1. point source
2. non-point source |
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Term
| In class Lake Washington in seatle was talked about to describe what major occurance (also be able to describe the lessons learned from that incidence) |
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Definition
EUTROPHICATION!!
-specifically the role of sewage in eutrophication and a demonstration of the role of point source pollution causing eutrophication and reversal of eutrophication with sewage diversion |
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Term
| what specific act made it possible to regulate point source pollution in the US and require more treatment of sewage? |
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Definition
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Term
| what are 2 strategies for dealing with eutrophication (be able to explain each) |
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Definition
1. treating symptoms of algal blooms
- increase algal grazing by manipulating the food web)
-kill the algae (aglaecide) using CuSO4
-reduce light availability (aquashade)
2.treat the problem with phosphorus
-reduce P inputs to the lake (External loading)
-buffer strips, retention ponds and silt fences (best management practices) |
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Term
| what are the best management practices for preventing phosphorus into lakes |
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Definition
| buffer strips, retention ponds and silt fences (best management practices) |
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Term
| what is internal loading (examples) |
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Definition
| input of nutrient to epilimnion within the lake itself (ex P in hypo sedicements can return to epi, lakes with high flushing rates usually respond to P reductions like lake washington.. flushing reduces xs P in the lake, lakes with low flushing rates may need many years to reduce P levels) |
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Term
| list 2 ways you can try to control the availability of P in a lake |
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Definition
1. water column oxygenation (such as a fountain) can cause iron to form a FePo4 complex making oxgygen present)
2. cation additions (Al, Ca, Mg)
can cause cation plus PO42- to complex to go from dissolved to solid |
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