HR: 16:45h
AN: NB14E-06 INVITED     [Abstracts]
TI: Abundance of Macroalgae in Florida Springs: Understanding the Role of Nutrients.
AU: * Pinowska, A
EM: pinowska@msu.edu
AF: Michigan State University Department of Zoology, 203 Natural Science, East Lansing, MI 48824 United States
AU: Stevenson, J R
EM: rjstev@msu.edu
AF: Michigan State University Department of Zoology, 203 Natural Science, East Lansing, MI 48824 United States
AU: Frydenborg, R
EM: Russel.Frydenborg@dep.state.fl.us
AF: Florida Department of Environmental Protection, 2600 Blair Stone Rd. MS 6511, Tallahassee, FL 32399 United States
AB: In the last 4 decades Florida springs have experienced a large increase in nutrient concentrations. High nutrient levels are blamed for excess growth of thick algal mats in many springs. Reach-scale benthic algal assessments were conducted to characterize spatial extent and thickness of macroalgae and periphyton at 60 sites within 28 springs, where physico-chemical data were also collected. Diatom indicators were developed using the weighted average approach to infer nutrient conditions. Algal-nutrient relations were determined with % cover and thickness of all macroalgae and each common taxon independently and with measured and diatom-inferred nutrient concentrations. The most common taxa of macroalgae were a blue green alga Lyngbya wollei found at 57 % sites and a green alga Vaucheria sp. found at 55 % sites. Over half of the bottoms of Florida springs, on average, were covered by macroalgae. Analyses indicated a threshold in Vaucheria sp. cover response at 0.6 mg TN/L, but no such response was observed for Lyngbya wollei which seems to have a high tolerance for low nutrient concentrations. Further laboratory experiments were conducted to determine phosphorus and nitrogen limitation of Vaucheria sp. and Lyngbya wollei growth rates and to confirm limiting nutrient concentrations for growth of the macroalgae.
DE: 4845 Nutrients and nutrient cycling
DE: 9810 New fields (not classifiable under other headings)
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly