Blue-green algae found in Damariscotta Lake

Posted:  Friday, September 14, 2018 - 8:15am
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A type of blue-green algae, more accurately referred to as a cyanobacteria, has been found in a cove in Damariscotta Lake for the third year in a row. While likely present in many Maine lakes, cyanobacteria can grow faster and become more obvious when waters are warm and have more nutrients in them, often referred to as an algae “bloom.” While the cyanobacteria found in Damariscotta Lake is extremely localized, sparse, and not widespread or dense enough to be classified as a true “bloom,” it does act as a sobering reminder that the lake is sensitive to additional inputs of nutrients and pollution, and presents a harrowing vision of the potential future.

A sample collected from the lake by Garrison Beck of Midcoast Conservancy on August 30 was delivered to the Maine Department of Environmental Protection on August 31 for identification. The cyanobacteria were determined to be of the genus Oscillatoria, and determining an exact species is quite difficult. As this is a type of cyanobacteria, it has the potential to generate toxic substances. However, it is very difficult to know when toxins are being created and/or released by the bacterium. If there are only a few particulates floating around in the water column, it is unlikely to be dense enough to lead to any noticeable levels of toxicity. If waters ever begin to turn a bluish-green and begin looking like pea soup, only then is it very likely that the cyanobacteria can be harmful to people and pets. The cyanobacteria found in Damariscotta Lake are likely not yet so dense to be harmful.

The single best thing to do to prevent more growth of cyanobacteria is to prevent nutrient pollution of any kind. Pollution not only comes from fertilizers being applied near water bodies, but also nutrients which are naturally occurring in the soil and pollute the water when soil is eroded from roads and shorelines. Pollution may also come from septic systems which are older than their useful life or are not being maintained properly.

Everyone who cares about Damariscotta Lake has a role to play in preventing pollution. Landowners who are unsure about their septic system near any river, lake, or stream can choose to have it inspected. There is no fine or penalty that can result from inspection, and it is an easy way to protect one’s investment in property and Damariscotta Lake. Gravel roads and culverts are also a prominent source of pollution from soil erosion. Road associations, towns, and private landowners can all improve gravel road design and management for water quality, and some may be eligible for cost-sharing assistance from Midcoast Conservancy. Please contact Garrison Beck at Midcoast Conservancy for more information at 207-389-5157.