Volume 2, No. 3
Nutrient Exchange in Florida Bay
Nutrients are one of the hottest topics of concern for Florida Bay. Questions revolve around sources of nutrients, including what happens to them when they get to Florida Bay, and the role they play in algal blooms in the bay. They Florida Bay and Adjacent Waters Program Management Committee made nutrients the focus of the second in a series of five questions designed to reveal the nature and function of the bay (See Vol 1. No. 1). Question 2 asks what the relative importance of nutrient inputs to the bay is, compared to the cycling of nutrients within the Bay.
According to Dr. David Rudnick, leader of the Florida Bay Nutrient Research Team and scientist with the South Florida Water Management District, Question 2 is important to the South Florida restoration effort for two primary reasons. "If the main mechanism of ecological restoration is to restore freshwater flow to Florida Bay, it is important not to introduce a possibly larger problem through the addition of harmful levels of nutrients and toxins," Dr. Rudnick stated. "Understanding the cycling of nutrients within the bay is also critical. It is possible that changes in Florida Bay are partially attributable to nutrient inputs and partially attributable to changes in nutrient cycling that have been indirectly caused by decreased freshwater flow and increased salinity. We need to understand the direct impacts of further additions of nutrients and the indirect effects of salinity change," summarized Dr. Rudnick.
Approximately 26 research projects are currently underway in Florida Bay focusing on nutrient dynamics. Nutrient studies revolve around two primary efforts, model development and field research. The U.S. Army Corps of Engineers is leading an effort to develop a water quality computer model designed to predict the influence of water mangaement changes on nutrient levels within Florida Bay. Long-term monitoring and research programs generate the data used in model development.
The South Florida Water Management District has supported a water quality monitoring program through the Southeastern Environmental Research Program at Florida International University since 1991. District scientists, along with collegues from FIU and other universities, have also focused on determining the sources of nitrogen and phosphorus in Florida Bay and the fate of nutrients within the bay. Most recently, attention has focused on the importance of the area where mangroves meet the bay. Determining the degree to which mangroves are a source of nutrients, or serve to trap nutrients, will help to accurately assess the levels of nitrogen and phosphorus entering the system through this interface.
"So far we have identified the main inputs of nutrients," said Dr. Rudnick. "We need more information on inputs from the Gulf of Mexico and the atmosphere. Also, more focus must be given to the recycling of nutrients within the bay such as between the sediment and water column. We must understand the system as it is now in order to understand the changes that will result with restoration," Dr. Rudnick summarized.
For more information on the PMC, please visit their web site at: http://www.aoml.noaa.gov/flbay/
Photo courtesy of South Florida Water Management District