Beach Closed: Blue Green Algae Threatens Lakes and Rivers

It’s a hot summer day and perfect for a swim. But the beach is closed due to an algae bloom. Sadly, this is becoming a more and more common occurrence due to an organism called blue green algae or cyanobacteria. It is a prokaryotic or simple celled organism originally considered to be algae, but then reclassified as bacteria. Nitrogen and phosphorous are often used as fertilizer on farms and lawns. However, when too much of these chemicals are used they can wash into lakes, rivers, and streams, thus causing major algal blooms. These blooms cause scum on the surface of waterways and take so much oxygen that fish suffocate. In addition, water with serious algal blooms are also not considered safe for people or pets. It has affected lakes and rivers acoss the country.

Angela Shambaugh, an aquatic biologist with the Vermont Department of Environmental Conservation, said that cyanobacteria produce a couple of different toxins which can cause skin rashes. She also said children and pets should be kept away from any areas with algal blooms. In addition, Shambaugh said that algal blooms reduce oxygen concentrations, which have resulted in fish and mussel die-offs in Lake Champlain.

According to Foul Water Season, by Laura Tangley, published in The National Wildlife Federation July 2015, there is evidence that harmful algal blooms are on the rise. The article states that the loss of forests and wetlands which help to absorb nitrogen and phosphorous contribute to the problem. Warmer water and heavier rainfall also create a more suitable enviroment for blooms as well as higher runoff that can wash nutrients into streams and rivers. Tangley recommends applying only the precise amount of fertilizer needed, planting cover crops, and restoring wetlands. Shambaugh concurred saying that blooms seemed to be lasting longer and cited one which lasted into October of last year.

The Union of Concerned Scientists also criticized the overuse of fertilizer as one of the main causes. In their article “Subsidizing Waste: How Inefficient Farm Policy Costs Taxpayers, Businesses and Farmers Billions” (2016), they state that farm subsidies often encourage an overeliance on certain crops, such as corn and soybeans. The UCS cited a study in Iowa in which researchers planted prairie strips or small areas of native plants among farm crops. The study found that planting these on just 10 % of farmland reduced nitrogen loss by 85 %, phosphorus loss by 90% and sedimentation by 95%. Lisa Nurnberger, the media director for the UCS, sent information concerning the red tide in Florida. The organism that causes red tide is not the same as the one that causes blue green algae, but it is a related issue. According to studies she cited, the red tide has been linked to both runoff from cattle farms and residential development as well as rising sea temperatures due to climate change.

While certain crops have received strong criticism, Shambaugh said any nutrient running into the water can cause problems. Agricultural runoff has received large amount of the blame. However, Shambaugh said this is largely a matter of location. In some areas, agricultural runoff produces the largest amount of runoff and in other areas, lawns and gardens produce the largest amount. She also pointed out that areas with more concrete also have higher runoff, because there is no soil to absorb the rain.

While this is a serious issue, there are steps that can be taken. The UCS recommends reducing reliance on commodity crops and making the adoption of conservation practices a requirement for receiving subsidies. Shambaugh said it wasn’ t an easy problem to solve, but she recommended the Vermont Dept. of Health website for more information. In addition, reducing or eliminating fertilizer on lawns and gardens is also an important step.


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