We have an abundance of lakes in Delaware County to cool off and get refreshed. There’s Alum Creek Reservoir, Delaware Lake, Hoover Reservoir, O’Shaughnessy Reservoir and a large number of privately owned lakes and ponds that can be good cooling spots. Have you ever been on the shore or in a boat this time of the year and noticed a green tinge to the water? Ever wonder what that is from or if it is safe to swim?
I’m sure you have heard of blue-green algae by now. This toxin has closed down the city of Toledo’s water treatment plant, lakes at state parks, and swimming beaches along the shores of Lake Erie. Recent events in Florida have indicated dangerous levels of blue green algae also.
But some levels of algae in the water are necessary for a healthy aquatic environment. Blue-green alga is actually not an alga at all – it is a cyanobacteria toxin. It is a naturally occurring food source for aquatic organisms. Low levels of this toxin are an important link in the food chain and at low levels are not toxic or unsafe for humans or pets. However, if the levels become too high, as seen last year in Lake Erie and other lakes, they become known as Harmful Algae Blooms (HABs) and pose a threat to human health and pet safety.
We have been fortunate that our weather patterns last summer have been moderate and the algae levels have not reached the levels of the past two years. Extremely high temperatures combined with heavy storm events can quickly cause HABs to return. Shallow lakes, such as Grand Lake St. Mary’s and the western basin of Lake Erie are particularly vulnerable to HABs due to the ability of sunlight to reach the floor of the water body and accelerate the growth of algae. And phosphorous levels in our soils — whether it be from farm fields, golf courses, failing home sewage systems, or lawns and landscaping — will always be potential contributors to this problem.
Rainfall runoff from our land picks up any available phosphorous and empties it into our lakes and streams. Phosphorous is a fertilizer which contributes to the growth of algae.
Brad Ross is communications specialist at the Delaware Soil and Water Conservation District. He can be reached at firstname.lastname@example.org.