Eye on the Environment: Fewer harmful algal blooms being reported this year

GREG SMITH
Greg Smith

Harmful algal blooms, or HABs, usually caused by nutrient pollution and subsequent excessive blue-green algal growth (and associated cyanotoxins), have been a frequent problem in Ohio and across the U.S. over the past few years.

However, the number of HABs reported across Ohio this year is less than previous years.

These algal blooms are the result of excessive nutrients and warmer weather conditions, which stimulate algal growth, often covering the surface of the water. This can be a serious issue because cyanotoxin-producing blue-green algae, or cyanobacteria, frequently occur in drinking-water sources and recreational waters.

Any waters containing excessive concentrations of cyanotoxins (e.g., microcystin) are unusable, as the toxins can cause severe illness or even death if enough of the contaminated water is consumed.

In addition, aquatic organisms can accumulate the toxins – which can indirectly affect humans who consume those organisms – or be adversely affected due to cyanotoxin exposure, thereby causing an ecological imbalance to the aquatic environment.

Several harmful algal blooms have been reported across Ohio in previous years.

One of the first extensively publicized occurrences of toxic algae was in Grand Lake St. Marys during the summer of 2010. Thousands of fish were killed, and recreational use of the lake was limited severely due to human health concerns. Toxic-algae-warning signs were again posted during the summer of 2015, and elevated algal bloom/toxin advisories still are in effect this summer.

Lake Erie is another Ohio water body that frequently has had environmental issues due to algal blooms.

The worst recent incident was in the summer of 2014, when the city of Toledo had to issue a warning to residents not to use the water because of excessive microcystin contamination caused by toxic algae in Lake Erie.

Last summer, a severe bloom of blue-green algae was observed across the western half of Lake Erie, dominated by microcystin-producing cyanobacteria. The National Oceanic and Atmospheric Administration reported unsafe toxin concentrations in Lake Erie and thus advised people and their pets to stay away from areas where scum was forming on the water surface.

So why have there been so many occurrences of toxic algal blooms in previous years, but so far this summer only a few advisories across Ohio?

It most likely is due to lower spring rainfall levels across Ohio and the state-funded phosphate-reduction program, whereby farmers are paid to implement conservation practices designed specifically to reduce phosphate loads to the receiving waters.

In fact, the NOAA is predicting a less severe algal bloom in the western part of Lake Erie compared to last summer, also due to lower spring rainfall levels and the state-funded phosphate-reduction program.

So how can we help prevent algal blooms and HABs?

One way is to apply phosphate-free fertilizer to our lawns and at the recommended amount and application frequency. This will help prevent nutrient runoff that eventually ends up in nearby surface waters.

In addition, maintain septic systems to prevent nutrient-laden wastewater from leaking and seeping into nearby lakes and streams.

Greg Smith is a member of the Hilliard Environmental Sustainability Commission and senior research scientist at Great Lakes Environmental Center.