Regulation of Macroalgal Growth and Accrual by Nutrients
 in Florida Springs

Participants: R. Jan Stevenson (PI, Michigan State Univ), J. Sickman (co-PI), K.R. Reddy (co-PI)

Funding Agency: Florida Department of Environmental Protection

Problem Statement - Nuisance algal growths have been observed in many karst springs in Florida and have been associated with increases in human activity and nutrients, particularly nitrate. Development of nutrient criteria and the tools to implement the criteria will help protect the springs and other water bodies of the state, but is challenging given the complexity of nutrient sources to and recycling within the springs. Initial surveys of algal densities and nutrient concentrations has demonstrated that regulation of nitrogen may control macroalgal growths in some Florida springs, but more evidence is required for development of specific nutrient criteria. Understanding which nutrients are limiting is critical for control of nuisance algal and has stimulated the formation of the Florida Springs Research Initiative (FSRI) to develop management strategies to solve this problem.

Research Activity - This project seeks to: 1) determine the concentrations and potential sources of nitrogen and phosphorus that regulate macroalgal growth and biomass accrual in Florida Springs and 2) determine effects of non-nutrient environmental factors on macroalgal growth and biomass accrual in Florida Springs. Several research approaches are planned: 1) more detailed statistical analysis of existing data on water quality and algal distribution; 2) investigation of nutrient and algal dynamics along nutrient gradients within the outlets to karst springs; 3) highly controlled algal growth experiments done in the laboratory; 4) algal growth experiments done in artificial stream channels and 5) stable isotopic analysis of nitrate to identify potential N sources to springs.