GLIN==> Researchers Study Roundup as Possible Cause of Harmful Algal Blooms

Researchers Study Roundup as Possible Cause of Harmful Algal Blooms 

 

April 27, 2009

 

FOR IMMEDIATE RELEASE

 

COLUMBUS, OH - The herbicide Roundup may be contributing to the growth of
harmful algal blooms in Lake Erie, according to Ohio Sea Grant researchers.
Drs. R. Michael McKay and George Bullerjahn of Bowling Green State
University are studying the impact of glyphosate, a phosphonate and the main
ingredient in the commonly used herbicide, on the strains of blue-green
algae found in Lake Erie. 

 

Phosphorus has long been known to act as fuel to blue-green algae, and
efforts in the 1970s reduced harmful algal blooms and nuisance algae by
limited phosphorus loading in the Lake Erie watershed. However, the last 15
years have seen an increase in the growth of the toxic blooms, contributing
to an ever bigger Dead Zone in the lake's Central Basin and massive fish
kills each summer. 

 

Scientists have believed phosphonates to be inaccessible to plankton, but
McKay and Bullerjahn have begun to look to glyphosate as a potential
phosphorus source with funding from Ohio Sea Grant.

 

"Our research is finding that Roundup is getting into the watershed at peak
farming application times, particularly in the spring," McKay explains.
Their work has shown that glyphosate cannot be detected in the lake in April
but can be found from mid-May through July, after crops are planted, which
corresponds to the forming of the Dead Zone. They have also discovered that
the blue-green algae, also known as cyanobacteria, are capable of using
phosophonates.

 

"It turns out that many cyanobacteria present in Lake Erie have the genes
allowing the uptake of phosphonates, and these cyanobacteria can grow using
glyphosate and other phosphonates as a sole source of phosphorus,"
Bullerjahn says.

 

McKay and Bullerjahn are now determining exactly what the algae do in a
glyphosate-rich environment. "We know that blue-green algae native to Lake
Erie can use the compound," says McKay. "What we have not determined is the
extent to which they are using it, and if you see a massive change in the
micro-organisms in the lake." 

 

If glyphosate is, indeed, found to be increasing the amount of algae in Lake
Erie, researchers can create new pollution models to account for the
additional phosphonates as a phosphorus source. Such models will help
determine if the impact of glyphosate use warrants more attention and
possible control. The study will conclude in 2010.

 

To read more about this Ohio Sea Grant-funded research, visit
http://ohioseagrant.osu.edu/_documents/twineline/v31i1.pdf.

 

The Ohio State University's Ohio Sea Grant program is part of NOAA Sea
Grant, a network of 30 Sea Grant programs dedicated to the protection and
sustainable use of marine and Great Lakes resources. For information on Ohio
Sea Grant and Stone Lab, visit ohioseagrant.osu.edu.

###

Contact: 

Dr. R. Michael McKay, Professor, Bowling Green State University:
419.372.6873, rmmckay at bgnet.bgsu.edu

 

Dr. George Bullerjahn, Professor, Bowling Green State University:
419.372.8527, bullerj at bgnet.bgsu.edu

 

 

Stacy Brannan

Associate Editor

Ohio Sea Grant and Stone Laboratory

1314 Kinnear Road

Columbus, OH 43212

614.292.8949

brannan.16 at osu.edu

 

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