Blooms That Harm

Algae grows in most - if not all - waterways in the Finger Lakes Region and is generally seen as a natural part of our lakes, even if it can make swimming a little uncomfortable. Recently, something that I thought only happened in faraway places like the Red Sea, prevented my own enjoyment of a local lake: a harmful algal bloom.

Harmful algae are not the same as the green plant-like algae that we see growing in clumps along the shores. Rather it is a cyanobacteria, a single-celled bacterium, of which there are many different kinds. Some cyanobacteria are considered beneficial; spirulina, for example, is sold in tablets which are taken by some as a protein and nutrient supplement. Other kinds of cyanobacteria, such as the blue-green algae currently growing in lakes across New York state, are harmful if ingested or exposed to the skin for prolonged periods of time. Examining data from 2012 to the present on the NYS Department of Environmental Conservation’s webpage, it is apparent that some of the state’s lakes regularly experience blooms. According to the data given, Honeoye Lake has seen one every year since 2012, including some years with highly toxic blooms.

What causes a harmful algal bloom? Scientists are still studying the triggering effects of blooms but data points to excess nutrients, such as phosphorous, being washed into the lakes as one likely cause. Turnover is when the water and nutrients at the bottom of a body of water get circulated up to the surface and back round again due to differences in the density of warm and cool water and wave action caused by wind. In years with warmer, less windy winters, large lakes may not achieve complete turnover which may then lead to blooms. Smaller lakes and ponds may also turn over repeatedly some summers, which might trigger harmful blooms.

The exact causes of harmful algal blooms may still be a mystery, but scientists do offer some suggestions for how we can to help protect our waters. First, it is recommended both everyday citizens and farmers reduce the amount of fertilizers used as the phosphorous they contain causes the harmful algae to grow quickly and lusciously just as it would a field of crops. Septic tanks should also be maintained to reduce leakage that could be harmful to our waterways.

Luckily, my lake, Keuka, re-opened within two weeks of the initial closing and the kids and I can enjoy the refreshing waters once again. I am left hoping that this winter will be cold and windy to increase turnover so that our lake can be healthy the entirety of next summer.

For more information including photos and to check which lakes are currently affected by harmful algal blooms, please visit:

By Gabrielle L. Wheeler

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