Research
CURRENT
Oysters and Associated Restoration on Sanibel (2008)
Oyster reef habitats were once quite common along Florida’s southwestern coast based on excavations of shell mounds or ‘middens’ and historical records dating back to the 1800s. Shallow subtidal and intertidal oyster reefs were once dominant components of the Caloosahatchee estuary, and remnant populations can still be found in the River as well as in Pine Island 
Sound and in and around Sanibel and Captiva Islands. Oyster reefs create complex three-dimensional, reef structure attracting numerous invertebrates and finfish. These "ecosystem engineers" support numerous documented species by FGCU researchers (Volety and Tolley,2003) such as the mud crabs such as Panopeus simpsoni and Eurypanopeus depressus, numerous filter-feeding porcelain crabs such as Petrolisthes armatus, snapping shrimp, Alpheus heterochaelis, and crown conch, Melongena corona. Reefs also harbora diverse community of resident fish such as Florida blenny, Chasmodes saburrae, skilletfish, code goby, Gobiosoma robustum, Gobiesox strumosus, feather blenny, Hypsoblennius hentz and Gulf toadfish, Opsanus beta. Larger predators include species such as black drum, Pogonias cromis. In 2008, the SCCF Marine Laboratory and City of Sanibel Natural Resources department staff initiated a pilot study to assess potential for oyster reef restoration in Clam Bayou and Tarpon Bay. During 2008 and 2009 we will be assessing oyster recruitment, mapping existing oyster populations and adjacent seagrass (primarily Halodule) populations in Clam Bayou. Funding is currently being sought to expand these studies in association with enhanced flow associated with the addition of culverts in 2006 and the opening of Blind Pass in late 2008 or early 2009.
Widgeon Grass (Ruppia maritima) Restoration and Monitoring in the Caloosahatchee Using Herbivore Exclosures
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.
Bioavailability and Sources of Nutrients and Linkages to Nuisance Macroalgae (2008-2010)
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.
Development of a real-time SAV management tool using RECON (2007-2008)
Representation of the subsurface light field is a critical component of pelagic ecosystem models and for protection and restoration of SAV (Submerged Aquatic Vegetation) habitats. Four optical models were developed for and specifically tuned to the Caloosahatchee River and Estuary, San Carlos Bay and Pine Island Sound located in Southwest Florida during this project. Development of these tools provide local resource managers with a real-time assessment of estuarine conditions relevant to SAV by integrating seagrass light requirements with RECON. These tools are critical choosing appropriate SAV restoration sites and evaluating the effect of large scale everglades restoration projects, such as C-43 reservoir construction.
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
Mangroves of Sanibel-Captiva (2003-2008)
A conspicuous habitat on Sanibel and Captiva Islands are mangroves. Mangroves provide refuge for wading birds and provide storm and flood protection. Distributed throughout the islands are 27 study plots,approximately 36 feet in diameter. Within the plots, all large trees are permanently tagged and the number and of seedlings are measured.The health of mangrove habitats depends on tidal flushing, which has been altered over the course of human development of tropical coasts. Research on the factors contributing to degraded mangroves and the best way to improve or enhance mangroves is the subject of ongoing study. Further, restoration activities to increase high quality mangrove habitat on Sanibel and Captiva are led by SCCF marine laboratory.
Related Publications: Milbrandt et al 2006, Proffitt et al 2006
Clam Bayou Mangroves (2003-2008)
Despite repeated attempts to re-introduce tidal flooding to this mangrove-lined lagoon, Clam Bayou remained isolated from 
tidal flow resulting in severely degraded mangrove wetlands. All reproductively productive mangroves were now standing dead snags. The purpose of this research was to characterize mangrove, fish, and seagrass communities in Clam Bayou in addition to a reference embayment to provide benchmarks for measuring restoration success. A box culvert provided a permanent tidal connection and a restoration solution for Clam Bayou in 2006. Now that the communities are well-characterized,predictions about the pace and direction of recovery can be inferred.
Related Publications: Final report to City of Sanibel, Restoration and Creation Conference Proceedings 2006, Journal of Coastal Research (in press), co-authored with James Evans, City of Sanibel
Bay Scallop Recruitment
Although bay scallops (Argopecten irradians) were once plentiful throughout much of Florida's west coast, they have virtually disappeared in most areas. An extensive scallop fishery existed in Tampa Bay as recently as the 1960s, but scallops are rarely found now. Charlotte Harbor also supported a commercial fishery some 30 years ago, but scientists believe poor water quality is in large part responsible for these declines. Currently, the most extensive bay scallop populations are located north and west of the Suwannee River, in the Steinhatchee and in St. Joseph Bay. As miners used canaries as ‘sentinels’ as an early warning system, bay scallops are being used as ‘biomonitors’, providing an early warning system for scientists who monitor the quality of Florida’s coastal waters. Scallops are currently being stocked at Anclote River, Homosassa River, and Tampa Bay. It is hoped that scallop restoration efforts undertaken in areas north of us will eventually benefit this area with new recruitment and viable adult populations.
SCCF Marine Lab staff, through a grant from the Charlotte Harbor National Estuary Program (CHNEP), are continuing to monitor bay scallop recruitment in Pine Island Sound and Tarpon Bay, along with scientists from FWRI (Drs. Arnold and Geiger), Mote Marine Lab and the Charlotte Harbor NEP (Dr. Leverone). Currently, Coen and Thompson are responsible for nine of the recruitment monitoring stations. The larger Fish and Wildlife Research Institute’s (FWRI, located in St. Petersburg) effort is using this information in the larger statewide monitoring program, along with adult monitoring and juvenile/spat enhancements. FWRI staff assess recruits from our samplers in their lab for consistency across the state. We will continue to deploy new scallop monitoring units monthly and collect the previously deployed units for enumeration.
Water Quality and Habitat Assessments In and Around Captiva, 2008-2010
SCCF Marine Lab personnel (Drs. Coen, Bartleson, Milbrandt, Rybak, Mr. Thompson) initiated a two year study of local water 
quality problems on Captiva and adjacent waters within Blind Pass and Clam Bayou. The work will focus on identifying sources of water quality problems such as bacterial contamination resulting in closures of local beaches and shellfish harvesting grounds. It will use our mobile RECON unit, along with other existing tools at the lab; Lee County will run our nutrient and Enterococcus samples at the over 30 sites to be examined. The study will also inventory and map (GIS, remote sensing) seagrass resources and help to identify the severity of nutrient enrichment problems in local water bodies which may cause detrimental impacts to seagrass and other natural resources. The study will begin in early October, 2008 and is funded by the Lee County’s Tourist Development Council (TDC).
COMPLETED
Physiological Responses of Tape Grass (Vallisneria americana) to Light, Temperature and Salinity
Seagrasses
and brackish water submersed aquatic vegetation (or SAV) like tapegrass
(Vallisneria americana) are valuable components of estuarine
ecosystems. These plants are not actually in the family of grasses, but
are similarly monocots. All flowering plants are divided into dicots
and monocots (the latter name most simplistically refers to the
singleseed leaf produced by the embryo). A two year study (2006 to
2008) of physiological responses of tape grass to environmental
parameters supported by the SFWMD, was just completed. A series of
experiments measuring the growth and photosynthetic rates of tape grass
at two salinities (0 and 10 ppt), and two light levels (42 and 331 µE
m-2 s-1) at six different water temperatures were conducted in order to
determine the relationship between the environmental parameters and
photosynthetic rates and ultimately plant growth as a surrogate for
tape grass health. The temperature ranges tested covered seasonally
observed river temperatures (14 to 34ºC). Plant growth rate is known
increase with temperature to an optimum temperature and then
decline,and this optimum temperature was not known for local tape
grass, and it could depend on light level and salinity. Photosynthesis
vs. irradiance(P-I) curves were produced at each temperature for each
treatment. Leaf elongation rates were close to zero at the lowest
temperature (13°C),generally increased with temperature to an average
of 1.3% per day at30°C, and were significantly lower in the high
salinity treatments. The low light treatment leaves grew the fastest
except at 13°C and 32°C,but the high light, low salinity plants had the
largest biomass increase (including new shoots and roots). Longest
average leaf lengths and highest elongation rates were obtained in the
30°C experiment. The highest maximum photosynthetic rates (Pmax) were
at 30 and 32°C. The lethal temperature at 0 ppt was 36°C, which is a
temperature that is reached in shallow areas where the water is dark
from tannins. The results of these measurements will be used to provide
information for formulating a tape grass model that can be used to
predict response of tape grass growth to water management decisions
affecting salinity.
Caloosahatchee Estuary Seagrass / SAV Monitoring
Under a
contract with SFWMD, SCCF monitored submersed vegetation from
upriver near Beautiful Island to San Carlos Bay from 2004 until spring
2008.This monitoring project was designed to detect changes in
seagrass health and coverage in response to water quality changes. The
data show a dramatic response to long period of high volume river
discharges of dark water. During this period, turtle grass coverage
declined by 70%at Pine Island Sound sites. Subsequently, shoal grass
recovered rapidly to coverage greater than before the releases. Plants
throughout the main stem of the river never fully recovered from the dark
water releases thought light levels were usually suitable at a depth of
1meter and widgeon grass was lost from two sites. During 2006, a
drought caused salinities to increase at the upstream sites to levels
higher than the tolerance level for tape grass. These salinities
remained high until 2008’s rainy season, and the tape grass will need to
be replaced since there is no seed bank. The data from this monitoring
program will be used to judge the ecosystem effects of water quality
changes(success of Everglades RECOVER restoration efforts). The data is
also being used to calibrate and validate seagrass simulation models.
These models can be used, for example, to predict seagrass response
to changes in salinity at different light levels and temperatures.
Mangrove Restoration at Shell Point (2005)
A large mangrove die-off area within the protected coastline managed by Estero Bay Aquatic Buffer Preserve was targeted as a demonstration of new restoration techniques. Within the die-off area, black mangrove seedlings were thriving in circular patches of saltwort (Batis maritima). To test the prediction that saltwort surved as a nurse species to black mangrove seedlings, survivorship of black mangroves was determined in saltwort patches and outside. No surviving black mangroves were left after two months, while half of those planted in saltwort survived.
Related Publications: Final report to SFWMD, Hydrobiologia 2005, co-authored with Megan Tinsley, Audubon of Florida
Blue Crab Populations in the Caloosahatchee (2005-2007)
Blue crab landings data were compiled and analyzed to develop management targets related to the freshwater inflow to the Caloosahatchee estuary. Landings, effort and catch-per-unit effort of the blue crab landings were analyzed relative to environmental conditions within and around the Caloosahatchee River/Estuary. Major findings of this study are a correlation between the Secchi disk measurement and the catch per unit effort (CPUE) of crabs caught in the Caloosahatchee River. When Secchi disk readings were high (water was clearer), the CPUE was higher. Other water quality parameters, including flow rate did not correlate with landings.
Related Publications: Final report to SFWMD.
Ecological and Geographical Extent of Lake Okeechobee Releases to the Caloosahatchee Estuary (2005-2006)
Above-average hurricane activity and rainfall forced multiple releases of large volumes of freshwater into the Caloosahatchee Estuary in 2005 and 2006. The purpose of this research was to characterize the optical properties of water from the lake and basin sources and determine whether releases were responsible for light limitation in seagrass populations. Seagrass growth rate near the mouth of the Caloosahatchee River was significantly lower than other stations in the lower estuary. Lake releases were typified by high total suspended solids (TSS) and high colored dissolved organic matter (CDOM). Basin freshwater releases were high in CDOM. Mass spectrometry of dissolved organic matter (DOM) indicated that UV and bacterial degradation was occurring as DOM from freshwater sources significantly differed from DOM in the estuary.
Related Publications: Final report to SFWMD, Milbrandt, in prep, Estuaries and Coasts.
Macroalgae and seagrass monitoring during spring and summer of 2006.
As a consequence of large watershed influxes of nutrients and turbid water following several hurricanes, seagrass coverage
was reduced and algal biomass was high.
Macroalgal biomass, Karenia spp. cell density, and seagrass characteristics and growth rate in the water surrounding Sanibel were recorded in the spring and summer of 2006. Average macroalgal biomass in July in water surrounding Sanibel was high (M = 215 g d wt m-2) compared to other estuaries such as Biscayne Bay, and indicative of eutrophic conditions. At sites near the river, turtle grass percent cover was more than 70% lower than it was in 2005. Turtle grass abundance and growth were higher at sites farther from the river mouth, though epiphytic algal coverage was often high at all sites. Light attenuation underneath dense algal mats averaged less than 7% of surface irradiance, which is below the level required by seagrasses for growth.
Identification of Microbes Critical to the Enhancement of Seagrass Restoration (2007)
A greenhouse experiment was designed to repeat an experiment in the field. Seagrasses were transplanted with autoclaved sediments and 10 mM sodium sulfide to determine whether rhizome associated bacteria were moderating toxic effects from sulfide intrusion. The highest growth rates were recorded in untransplanted seagrasses, followed by seagrasses transplanted in native soils and the lowest growth was observed in seagrasses transplanted with autoclaved sediments. Subsequent analysis of DNA from the rhizome bacterial community was largely inconclusive.
Relevant Publications: Milbrandt, in press, Botanica marina. Final report to Charlotte Harbor National Estuary Program .
Repair and Maintenance of Seagrass Meadows in Charlotte Harbor (2007)
Propeller scarring of seagrass beds is a widespread problem in Charlotte Harbor. Shallow water and inexperienced boaters cause thousands of scars every year. New techniques for restoration of these propeller scars were monitored to determine feasibility of prop scar restoration in Southwest Florida. Injections of prop scars and bringing scars back to grade were monitored relative to targets and unmanipulated scars. While no significant differences were observed, there were greater growth rates in injected scars over the one year monitoring period. Differences among treatments was thought to be masked by heavy macroalgal biomass at the study site. Additional monitoring of the study site, plus additional restoration of propeller scars is planned.
Relevant Publications: Final report to West Coast Inland Navigation District.