Potential economic benefits of restoring commercial oyster harvest levels in Apalachicola Bay, Florida

Florida’s Apalachicola Bay has long been known for its oyster harvesting and processing industry, but a steady decline in oyster landings in the Bay has threatened the industry. The complex nature of the human and natural systems that together affect Apalachicola’s oyster reefs has created uncertainty about the long-term sustainability of the oyster fishing industry in Franklin County, which has prompted many questions about the ecology of the Bay and the economy of the region from a variety of stakeholders that directly or indirectly depend on the survival and successful restoration of the Apalachicola Bay oyster fishery. This 5-page fact sheet estimates the potential economic impacts associated with a successfully restored oyster reef in Apalachicola Bay, basing estimates on different hypothetical oyster harvest goals. Written by Robert Botta, Ed Camp, Christa Court, Caleb Stair, and Charles Adams and published by the UF/IFAS Food and Resource Economics Department, it is designed to inform decision making and discussions related to restoration and resource management in the region. https://edis.ifas.ufl.edu/fe1085

Wetland Dynamics Inferred from Spectral Analyses of Hydro-Meteorological Signals and Landsat Derived Vegetation Indices

The dynamic response of coastal wetlands (CWs) to hydro-meteorological signals is a key indicator for understanding climate driven variations in wetland ecosystems. This study explored the response of CW dynamics to hydro-meteorological signals using time series of Landsat-derived normalized difference vegetation index (NDVI) values at six locations and hydro-meteorological time-series from 1984 to 2015 in Apalachicola Bay, Florida. Spectral analysis revealed more persistence in NDVI values for forested wetlands in the annual frequency domain, compared to scrub and emergent wetlands. This behavior reversed in the decadal frequency domain, where scrub and emergent wetlands had a more persistent NDVI than forested wetlands. The wetland dynamics were found to be driven mostly by the Apalachicola Bay water level and precipitation. Cross-spectral analysis indicated a maximum time-lag of 2.7 months between temperature and NDVI, whereas NDVI lagged water level by a maximum of 2.2 months. The quantification of persistent behavior and subsequent understanding that CW dynamics are mostly driven by water level and precipitation suggests that the severity of droughts, floods, and storm surges will be a driving factor in the future sustainability of CW ecosystems.

Radiocarbon in Marsh Periwinkle (Littorina Irrorata) Conchiolin: Applications for Archaeology

ABSTRACTIn coastal and island archaeology, carbonate mollusk shells are often among the most abundant materials available for radiocarbon (14C) dating. The marsh periwinkle (Littorina irrorata) is one of these such species, ubiquitously found along the Atlantic and Gulf coasts of the United States in both modern and archaeological contexts. This paper presents a novel approach to dating estuarine mollusks where rather than attempting to characterize the size and variability of reservoir effects to “correct” shell carbonate dates, we describe a compound-specific approach that isolates conchiolin, the organic matter bound with the shell matrix of the L. irrorata. Conchiolin typically constitutes <5% of shell weight. In L. irrorata, it is derived from the snail’s terrestrial diet and is thus not strongly influenced by marine, hardwater, or other carbon reservoir effects. We compare the carbon isotopes (δ13C and Δ14C) of L. irrorata shell carbonate, conchiolin, and bulk soft tissue from six modern, live-collected specimens from Apalachicola Bay, Florida, with samples that represent possible sources of carbon within their environment including surface sediments, marsh plant tissues, and dissolved inorganic carbon (DIC) in water. Ultimately, this paper demonstrates that samples obtained from wet chemical oxidation of L. irrorata conchiolin produces accurate 14C dates.

Observing Plumes and Overturning Cells with a New Coastal Bottom Drifter

A new platform, the Coastal Bottom Drifter, was designed and built to observe near-bottom environments in coastal regions. It is capable of observing properties by drifting near the bottom with a prescribed clearance or at a constant depth of up to 300 m. The platform can observe physical and biochemical parameters, such as temperature, salinity, oxygen, and velocities, and has the capacity to carry additional sensors to measure, for example, pH, turbidity, and nutrients. In addition, it can profile to the surface at chosen intervals and can be deployed for days or up to several months. The integrated Iridium communication allows the user to receive positions and data while the platform is surfaced, as well as send new missions to the instrument. The use of an acoustic bottom-tracking device allows the construction of a drifter trajectory while providing information about ocean circulation. Additionally, the ADCP provides information about suspended particles and possible sediment transport. These measurements are valuable in understanding coastal environments as well as the dominant physical processes that cause mixing and set the conditions for local biological activity. An example deployment in Apalachicola Bay shown in this study demonstrates the ability of the drifter to observe small-scale features, such as overturning cells and plumes of dense water, that are caused by local topography.