Eutrophication in water bodies
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Eutrophication in Water bodies. By: Kelly Toy. Overview. What is Eutrophication Eutrophication management Experiments Nitrogen or Phosphorus control Debate Case Study: Baltic Sea Recommendations. 1. What is Eutrophication?. Definition Sources Process Importance.

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Eutrophication in Water bodies

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Eutrophication in water bodies

Eutrophication in Water bodies

By: Kelly Toy


Overview

Overview

  • What is Eutrophication

  • Eutrophication management Experiments

  • Nitrogen or Phosphorus control Debate

  • Case Study: Baltic Sea

  • Recommendations


1 what is eutrophication

1. What is Eutrophication?

Definition

Sources

Process

Importance


Definition eutrophication

Definition - Eutrophication

  • Degradation of water bodies from overfertilization of nitrogen (N) and phosphorus (P), resulting in excess plant biomass and consequently oxygen and habitat depletion.

Removing microalgal blooms at the Olympic Sailing Venue, China.

Seagrasses covered with attached

algae in a Danish estuary.


Excess n and p from human activities

Excess N and P from Human Activities

  • N and P enters water through

    • Runoff

    • Wastewater treatment and industrial discharges

  • Agriculture

    • Excess fertilizers, manure

  • Combustion of fossil fuels

    • N in air  acid rain water


Eutrophication process

Eutrophication Process


Why does eutrophication matter

Why does Eutrophication matter?

  • Global expansion of dead zones

    • oxygen depleted areas where fish and wildlife are extinct

  • Decreased biodiversity

  • New species invasion

  • Toxic algal blooms (some cyanobacteria)

  • Aesthetically unpleasing

  • Severe impacts on fisheries

  • Economic detriment industries relying on water quality/ aquatic ecosystems (tourism)


2 eutrophication management experiments

2. Eutrophication Management Experiments

1970’s Schindler Experiment

Response

Effects on Lakes and Estuaries


1970 s experimentation 37 years long with entire ecosystem lakes

1970’s experimentation37-years long with entire-ecosystem lakes

D.W. Schindler found:

  • P controls phytoplankton

  • Reducing N increased cyanobacteria

    Response:

  • U.S. and Europe ban P in detergents

  • Ramp up P removal in wastewater treatment plants

Only N inputs

N + P inputs

Experimental Lake 226

Ontario, Canada


Effect on lakes and estuaries

Effect on Lakes and Estuaries

  • Water quality in lakes improved dramatically

  • Eutrophication in estuaries increased

    • N pollution grew tremendously since the 1970’s

    • N contributes to eutrophication in estuaries

      • (no N-fixing cyanobacteria, N can limit growth)

  • Definitons

  • Lake- Freshwater surrounded by land

  • Estuary- Freshwater inlet connects to ocean outlet

    • Salinity varies throughout water body


Dead zones in estuaries

Dead Zones in Estuaries

  • 146 coastal regions affected by anoxia

  • Eliminating fish and bottom-feeding life forms

  • Size of dead zones growing

    • Gulf of Mexico dead zone- state of New Jersey


3 n or p control debate

3. N or P Control Debate

Evidence for each side


Debate n or p control

Debate: N or P control?

  • Reducing P increased eutrophication in estuaries

  • Reducing N increased N-fixing cyanobacteria

  • Expert Liminologists are still debating which nutrient controls eutrophication

    • cannot perform Schindler experiments in estuaries

  • Each water body is condition specific

    • Region and environment/ecosystem


4 case study baltic sea

4. Case Study: Baltic Sea

Description

High Societal Stakes

Recommendations


Case study baltic sea

Case Study: Baltic Sea

  • 9 countries bordering

  • Low salinity estuary

  • N-fixers abundant

  • Spatial extent and intensity of Hypoxia (low O2) growing


Dual nutrient reduction strategy

Dual Nutrient reduction strategy

  • Abatement plan was signed by all Baltic Sea countries in 2007 cost $4 billion/year

  • Upgrade P urban sewage treatment

    • decrease eutrophication to levels in 1900-1920


High societal stakes

High Societal Stakes $$

  • Swedish Department of Agriculture calculates N reductions in the plan cannot be fulfilled unless a large part of Swedish agriculture is shut down

  • Damaging aquatic ecosystem

  • Economic detriment to fishing and water industries

  • Many Countries input

  • Many Countries affected


5 recommendations

5. Recommendations

Results should be well tested

Expensive

Other ways to mitigate Eutrophication


Recommendation

Recommendation

  • All beneficial effects of dual N and P control must be robustly predicted before implementing high cost of nutrient reductions

  • N abatement is a very expensive pilot study

    • May favor cyanobacteria instead of water quality

  • Do not install N removal technologies at ww treatment plant yet

  • Continue P reductions to reduce sedimentation

  • Reduce both N + P at the source


In the meantime

In the meantime

We can reduce N and P inputs without expensive treatment

Control Measures for Runoff of both N and P:

  • Decreased use of fertilizers

  • Containment and treatment of manure

  • Tillage practices that conserve soil

  • Vegetative buffers along shoreline

  • Maintenance and restoration of wetlands

  • Convert croplands sensitive to erosion to other uses that do not pollute waterways

  • Eating less meat – fewer fertilizers needed to grow grain for livestock and less manure


Conclusion

Conclusion

Eutrophication is destroying aquatic ecosystems

Experiments and Observations

How do we manage N and P?

Expensive

Societal effects on Countries


References

References

  • Carpenter, S.R. Phosphorus control is critical to mitigating eutrophication. PNAS2008, 105, 11039-11040.

  • Conley, D.J. et al. Hypoxia-Related Processes in the Baltic Sea. Environmental Science and Technology2009, 43, 3412-3420.

  • Schindler, D.W. et al. Eutrophication of lakes cannot be controlled by reducing nitrogen input: Results of a 37-year whole-ecosystem experiment. PNAS2008, 105, 11254-11258.

  • Lewis, W.M.; Wurtsbaugh, W.A. Control of Lacustrine Phytoplankton by Nutrients: Erosion of the Phosphorus Paradigm. International Review Hydrobiology2008, 93, 446-465.

  • Conley, D.J. et al. Controlling Eutrophication: Nitrogen and Phosphorus. Science2009, 323, 1014-1015.

  • Howarth, R.; Paerl, H.W. Coastal marine eutrophication: Control of both nitrogen and phosphorus is necessary. PNAS2008, 105, E103.

  • Schindler, D.W.; Hecky, R.E. Reply to Howarth and Paerl: Is control of both nitrogen and phosphorus necessary? PNAS2008, 105, E104.

  • Schindler, D.W.; Hecky, R.E. Eutrophication: More Nitrogen Data Needed. Science2009, 324, 721-722.

  • Schelske, C.L. Eutrophication: Focus on Phosphorus. Science2009, 324, 722.

  • Conley, D.J. et al. Response (to Eutrophication Policy Forum Debate). Science2009, 324, 724-725.

  • Bryhn, A.C.; Hakanson, L. Coastal eutrophication: Whether N and/or P should be abated depends on the dynamic mass balance. PNAS2009, 106, E3

  • Schindler, D.W.; Hecky, R.E. Reply to Bryhn and Hakanson: Models for the Baltic agree with our experiments and observations in lakes. PNAS2009, 106, E4.

  • Bryhn, A.C.; Hakanson, L. Eutrophication: Model Before Acting. Science2009, 324, 723.

  • Jacoby, C.A.; Frazer, T.K. Eutrophication: Time to Adjust Expectations. Science2009, 324, 723-724.


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