January 18th, 2007 12:23 EST
NOAA Study Identifies Potential Impacts on Aquatic Food Sources
NOAA National Centers for Coastal Ocean Science researchers have identified potential effects of the commonly used herbicide atrazine on phytoplankton—free-floating algae forming the base of the food chain for aquatic animals. Published in the January 2007 issue of the journal Pesticide-Biochemistry and Physiology, the study indicates protein levels in phytoplankton significantly decreased as a result of atrazine exposure.
Research was conducted on five algal species exposed to atrazine levels within the range of atrazine 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. 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. In phytoplankton species exposed to atrazine, NOAA researchers have observed significant decreases in size that may negatively affect higher level species in the aquatic food chain as this crucial food source loses nutritional value.
"Many aquatic animals such as clams and oysters rely on phytoplankton as a food source," said Marie DeLorenzo, NOAA research ecologist. "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."
"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."
NOAA, an agency of the U.S. Commerce Department, is celebrating 200 years of science and service to the nation. From the establishment of the Survey of the Coast in 1807 by Thomas Jefferson to the formation of the Weather Bureau and the Bureau of Commercial Fisheries in the 1870s, much of America's scientific heritage is rooted in NOAA. NOAA is dedicated to enhancing economic security and national safety through the prediction and research of weather and climate-related events and information service delivery for transportation, and by providing environmental stewardship of the nation's coastal and marine resources. Through the emerging Global Earth Observation System of Systems (GEOSS), NOAA is working with its federal partners, more than 60 countries and the European Commission to develop a global monitoring network that is as integrated as the planet it observes, predicts and protects.