Sabine Grunwald

Linking Terrestrial Nutrients to Red Tide Incidences in the Tampa Bay

Research Team
Time
Funding Source
Overview
Objectives
Results

Research Team

PI:

Gurpal Toor, Soil and Water Science Department, University of Florida, Gulf Coast REC, Balm, FL

Co-PI:

Amy Shober, Soil and Water Science Department, University of Florida, Gulf Coast REC, Balm, FL

Sabine Grunwald, Soil and Water Science Department, University of Florida, Gainesville, FL

Geoff Denny, Environmental Horticulture, Gulf Coast REC, Balm, FL

Chris Martinez, Agricultural and Biological Engineering, University of Florida, Gainesville, FL

Graduate students:

Jinseok Hong, Soil and Water Science Department/School of Forestry and Conservation, University of Florida

Lori Clark, Soil and Water Science Department, University of Florida

Time

09/2007 to 06/2008

Funding Source

Research Innovation Fund, IFAS, University of Florida

Overview

Florida’s water resources are being threatened by rapid population growth and land use change. We propose to use remote sensing and GIS tools to develop a framework to conduct soil and water sampling in the Alafia river of Tampa Bay Watershed. This information will be used to develop relationship between spatial distribution of nutrients in the various land-use categories and water quality parameters. The increased understanding of land-water linkage would lead to development of solutions to mitigate impacts of urbanization on water quality, specifically on red tide outbreaks.

Rationale: Harmful algal blooms have long plagued the west coast of Florida. Karenia bevis is a photosynthetic dinoflagellate known to cause red tides. K. bevis produces brevetoxins, which binds with sodium channels and affect nervous system response resulting in killing of fish and other marine life. The natural concentrations of K. bevis in the Gulf of Mexico are ~1,000 cells per liter of water (Tester & Steidinger, 1997). When concentrations of K. bevis approach 100,000 cells per liter, it result in large dense blooms and fish kills. Shellfish can also concentrate brevetoxins produced by K. bevis and may harm human health. Brevetoxins can also cause respiratory problems when they become aerosolized. To control incidences of red tide blooms, a comprehensive evaluation of its origin, physiology, and persistence is needed. Ii is known that red tide blooms are initiated offshore and then move inshore with wind or water currents. Whether anthropogenic pollution prolongs the duration of red tide is a topic of controversy among scientists but most agree that blooms are increasing in magnitude and are more abundant close to the shore. Figure 1 shows that the concentrations of K. bevis were approximately 20-fold greater within 5-km of shoreline (often approaching >1,000,000 cells per liter in Tampa bay) than 20-30 km offshore. This points out to possible contribution of terrestrial nutrients that increased concentrations of K. bevis close to the shore.

Results

[in progress]