The“ecosystem services” that submerged aquatic vegetation (SAV) beds provide include nursery areas for various species, sediment stabilization, food production, and nutrient uptake have been valued at $9,000 per hectare per year. Since the Caloosahatchee has over 5,000 hectares of shallows where various SAV species could potentially colonize,millions of dollars worth of  “ecosystem services” are being lost every year. The main stem of the Caloosahatchee River as of late has had almost no SAV though conditions appear to be generally appropriate for plant growth perhaps to a depth of one meter. This may be partly a result of: 1) insufficient plant biomass and production to exceed the level of plant grazing, and 2) too few seeds or plants to initiate any potential population expansions. Widgeon grass (Ruppia maritima),another submersed monocot has the ability to thrive throughout the river because of its wide tolerance to a large range of salinities (0 to 70 ppt). Initiated in the summer and fall of 2008, this study is addressing the need for a population that can be used to monitor effects of water quality changes. Approximately 50 m² of widgeon grass will be planted with individuals propagated in outdoor tanks. After the establishments of enclosed plots along a typically brackish section of the estuary, the one year study will be: 1)monitoring growth and spread from the exclosures; 2) determining potential grazing rates (by measuring loss from uncaged plants); 3)light attenuation thresholds; and 4) estimating bed sizes needed for uncaged plants to survive. Using the the established plots we will be able to judge the ecosystem effects of water quality changes (success of Everglades RECOVER restoration efforts) which we would otherwise be unable to do in the absence of thriving SAV populations.

A team of scientists from SCCF, Florida Gulf Coast University (FGCU), the University of Miami formalized a partnership with local governments to investigate the linkages between water quality and "blooms" of macroalgae. Following several active hurricane seasons and high volume discharges from Lake Okeechobee and the Caloosahatchee basin, a massive red algae bloom was observed in Lee County. While it was not the first report of red algae accumulations on local beaches, it caused public outcry for a solution and plan was developed by local governments. The plan was to secure grant funding for research on the causes of the massive algae blooms. Several teams of scientists competed for the funding to study the red drift algae problem and their proposals were evaluated by City of Sanibel and Lee county staff. Drs. Milbrandt, Coen, and Bartleson from SCCF were an integral part of the team that was selected to perform the study last fall. The research project goals are to examine bioavailable nutrients, including those released by the sediments and determine the connection with attached macroalgae growing off of Sanibel and Fort Myers beaches. The work will be conducted for two year period and will cover the 2 inshore stations near the causeway and 10 offshore area from Redfish Pass to Bonita Beach.

A related effort, in collaboration with Drs.Grizzle and Riegl from the University of New Hampshire and Nova Southeastern University, will use a combination of hydroacoustic, videosurveying and related ground-truthing to map positions of the sea floor off Fort Myers Beach, Sanibel and Captiva Islands in conjunction with ongoing efforts related to macroalgae 'blooms' existing work. SCCFdivers will collect bottom samples in conjunction with UNH and Nova scientists to assess accuracy and gather more detailed information.  A catalog of geo-referenced and groundtruthed sonar samples representative of the major categories of vegetation and substrates will be collected with a Biosonics DT-X echosounder and two multiplexed, single-beam digital transducers operating at frequencies of 38 and 420 kHz.  A SeaViewer model 550 color video camera will be deployed concurrently with the Biosonics system as in two different modes to provide supplementary data for the hydroacoustic survey.  Click here for the January 2009 Quarterly Report.  Click here for the October 2008 Quarterly Report.

Tape grass restoration (2008)

To help restore aquatic habitats in the Caloosahatchee River and Estuary, SCCF and partners launched an experimental project to learn if tape grass planted upstream of the Franklin Lock and Dam (S-79 water control structure) on the Caloosahatchee River can help re-seed the estuary downstream. Beds of tape grass provide prime habitat for native juvenile blue crabs, fish and other species that spend early developmental stages in shallow estuaries where they can hide from large predators. SCCF scientists and research assistants planted tapegrass Vallisneria americana in circular beds at five locations in the Caloosahatchee River. The native wide-bladed grass typically grows in Florida’s fresh or mildly saline waters. By planting upstream of the Franklin Lock and Dam, the new plants will be less vulnerable to changes in salinity levels nearer the coast and so may continue providing seed stock to downstream areas. The multi-year rainfall deficit has dramatically reduced the amount of freshwater runoff and river flows available to help maintain the right salinity balance for tape grass to grow in the Caloosahatchee Estuary. Tape grass for the study was provided by Lee County Hyacinth Control District, which provided the plants at no costs. SCCF planted three beds at each locations, one was surrounded by a wire mesh cage to prevent turtles and fish from eating the fresh grass.
Read the report.