Great Lakes faces stress from agricultural runoff

Article link

http://www.reuters.com/article/2011/10/04/us-greatlakes-idUSTRE7937CY20111004

Summary

Great Lakes, which contain one- fifth if the world’s fresh water and supply tens of millions people, are facing threat of ecosystem collapse because of agricultural run-off. There are many problems with the Great Lakes which have become more serious after years. The amount of food in the lakes is one of these problems. Too much agricultural run-off causes algae blooms in Lake Erie, but too little food makes fish starve in Lake Huron’s offshore waters. In the summer, algae blooms rose up to 2 feet thick and 10 miles wide in Lake Erie, covered some Lake Michigan coastlines. Although water treatment tried to remove toxin, unpleasant odor was still created. Another problem happens in deeper water where invasive mussels decimate the food chain. Prolificquagga mussels defeated zebra mussels and colonized vast of the lake bottoms. Important plankton that is the base of the lakes’ food web was filtered out. This caused small fish starved, and affected population of top lake predators such as whitefish, salmons as well. Fish biomass in Lake Huron has declined about 95% in the past 15 years. Fresh water shrimps have declined 94% in 10 years.

Scientists think the degraded ecosystem in Great Lake is the result of over phosphorous discharged from farm land, which create an oxygen -depleted "dead zone" in the Lake Erie. Scientists are recommending enforcement of cleaning water laws along with experimenting of using microbial agent or mussel - eating fish to kill mussels.

Analysis

Agricultural runoff is a major source of pollution, which is classified as non-point source. It is hard to identify single places where pollution is emitted. Nitrogen and phosphorous are key pollutants in agricultural runoff, which can cause algae bloom and dead zone in water ecosystem. As reported in the article, food web of the lake is deteriorated and biomass is decreasing. In addition, pollution can also slow down the fishery and tourism business which leans on the Great Lakes. Besides, the polluted lakes also generate 3rd party effect or negative externality on people health who lives near the lakes or consume fish caught from the lakes. According to the article the loss caused by pollution in the lake is estimated about $7 million. However, this number may not capture all social value of the lake.

The Great Lake pollution problem has existed for many years and becoming more serious day by day. The reason could be on the local government's management. It might fail to ensure the compliance from farmer with water - quality guidelines; or the budgets for water treatment was not enough.The fact that agricultural runoff are diffuse, not concentrated into a specific outfall and weather related makes it very hard to monitor and control. Traditional approaches like emission standards are not efficient because it is difficult to measure the amount of emission accurately. Therefore taxes applied on emission is problematic too. Taxes could be applied to the activities or materials that lead to emission, for example, taxes can be levied on amount of fertilizer or pesticides used by farmers. This method is to reduce the use of materials that later can end up in the lakes. Another method that can be applied is technology standard. Specified technology should be used in farm land that can guarantee acceptable amount of runoff. Or government can subsidy people to leave the land along the lake, not use that land for farming activity.

Prof. comment

Bit brief, but you have some of the main ideas related to limiting the amount of farming activity near the water.

8.5/10