An international group of scientists is renewing calls for policy makers to reduce both nitrogen and phosphorus when attempting to alleviate eutrophication or nutrient pollution problems in fresh and coastal waters. In the February edition of Science, the researchers argue that dual-nutrient reduction strategies are likely to be more successful due to complex interactions between nitrogen and phosphorus in fresh and coastal water ecosystems.
"If the overall goal of nutrient reduction programs is to re-establish balanced aquatic ecosystems, research tells us to focus pollution reductions efforts on both nitrogen and phosphorus," said co-author Dr Donald Boesch of the University of Maryland Centre for Environmental Science. "Efforts focusing on only one nutrient can possibly help freshwater systems, but tend to push pollution problems downstream into coastal and estuarine systems."
"Policy makers need to adopt holistic approaches when combating eutrophication," added lead author Dr Daniel Conley of Sweden's Lund University. "Heavily polluted estuaries can demonstrate either nitrogen or phosphorous limitations depending upon the season or location, so it is important that pollution reduction measures address the true root of the problem."
Excess nutrients often lead to harmful algal blooms and oxygen-deprived "dead zones" occurring in freshwater lakes and coastal waters. Scientists attribute these elevated nutrient levels to the production of fertilisers, increased fossil fuel emissions, and effluent from municipal and industrial waste water treatment.
