Researchers Say Levels of Nitrogen as Bad as Phosphorus for Algae Blooms
Blue green algae bloomThe common wisdom held that algae blooms could only be caused by high concentrations of phosphorus in freshwater lakes, but new research show increased levels of nitrogen as bad as phosphorus for algae blooms formation in lakes.
At its 2015 conference last May in Burlington, Vermont, the International Association for Great Lakes Research held a session on that topic. chaired by Dan Peckham coordinator of the Harmful Algal Blooms Workgroup of the New England Interstate Water Pollution Control Commission.
Blue-green algae contains cyanobacteria, which produce the cyanotoxins that make seasonal blooms harmful, while green algae are harmless, according to Peckham. Blue-green algae is the source of the seasonal toxic blooms on portions of Lake Champlain.
“Usually the concentration of cyanotoxins is associated with biodegradable dissolved phosphorus, but some people have been hypothesizing more recently that high levels of nitrogen may also be responsible,” ~ Dan Peckham, New England Interstate Water Pollution Control Commission
Unprotected farm fields yield topsoil as well as
farm fertilizers and other potential pollutants when heavy rains occur.Both nitrogen and phosphorus are needed to grow any kind of plant, including algae.
Nitrogen and phosphorus wash into water bodies and then release into the air. The chemicals come from stormwater, wastewater, fossil fuels, soaps and fertilizers, according to the Environmental Protection Agency website.
“Excessive amounts of growth are caused by high levels of both nitrogen and phosphorus. Nitrogen is not worse than phosphorus, but both need to be reduced. The bottom line is that nitrogen input needs to be controlled along with what we already know about controlling phosphorus input… If we only reduce phosphorus we may not get there fast enough in terms of getting a lake or even a marine system back to what we would deem desirable.” ~ Hans Paerl, Professor of marine and environmental sciences,University of North Carolina-Chapel Hill
Paerl said freshwater researchers have developed tunnel vision by focusing on phosphorus for so long. The same protocols that keep phosphorus out of lakes and streams apply to nitrogen. he added.
Nitrogen as Bad as Phosphorus for Algae Blooms in Lake
Nitrogen Levels Could Make Drinking Lake Water Unsafe
Elevated levels of nitrogen in drinking water are also known to cause health problems in young children, according to the Vermont Health Department. Last year algae blooms were responsible for contaminating drinking water supplies for several communities on Lake Erie.
Mike Winslow, a staff scientist at the Lake Champlain Committee, said he has never known of a time where blooms in Lake Champlain have affected the quality of drinking water in Vermont.
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