Published in the current issue of the journal 'Pesticide-Biochemistry and Physiology,' the study indicates protein levels in phytoplankton decreased as a result of atrazine exposure.
'Many aquatic animals such as clams and oysters rely on phytoplankton as a food source,' said NOAA research ecologist Marie DeLorenzo. 'Disruption to the cellular composition of phytoplankton species may negatively affect nutritional levels of the plant, resulting in decreased growth rates for those animals that consume phytoplankton.'
Research was conducted on five algal species exposed to atrazine levels within the range of concentrations that have been measured in the estuarine environment.
In the majority of the species tested, the amount of energy converted into protein from photosynthesis 'significantly decreased,' the researchers reported.
Photosynthesis is the process in green plants by which light energy is used to convert water and carbon dioxide into organic materials, producing oxygen as a byproduct.
Atrazine is one of the most heavily used herbicides in the United States. It acts as an inhibitor of photosynthesis by preventing the transfer of energy in certain plant species.
'The use of atrazine as a growth inhibitor in broadleaf and grassy weeds is an accepted practice beneficial to farmers and landscape professionals,' said Mike Fulton, a NOAA research fishery biologist. 'But it is equally important to gain an understanding of the potential effects of this herbicide on non-target aquatic plant species.'
In phytoplankton species exposed to atrazine, NOAA researchers observed decreases in size that may negatively affect higher level species in the aquatic food chain as this food source loses nutritional value.