Sedimentary Data from the Coastal Marshes Fringing the Lower Waccasassa River, Northwest Florida

The Waccasassa River is located in a small watershed situated along the middle section of the low-gradient, low-energy, sediment-starved Big Bend coast in west central Florida. The river mouth empties into the head of the shallow, microtidal Waccasassa Bay and the Gulf of Mexico. The lower end of the river and the surrounding coastline are dominated by coast-parallel Juncus roemerianus salt marshes up to 1.5 km wide. The sediment cover is thin, with the marsh surface typically less than 2.5m above the limestone bedrock. Scientists from the U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center investigated the sedimentary and geochemical properties of the saltmarsh sediments in order to increase understanding of the region's environmental history and the ongoing soil chemical processes. To this end, they obtained long and short sediment cores and surface samples from three sites along the margins of the river during field trips in December 2014 and February, 2015.

This data release details the sedimentary and chemical properties of these sediments. All ten cores were subjected to 2 cm-resolution analysis by a hand-held XRF (pXRF) to determine elemental concentrations, loss-on-ignition (LOI) was performed on eight long cores at 1 cm-resolution, and sediment physical parameters were quantified for eight short cores and all surface samples. Thirteen subsamples, extracted from seven cores at selected stratigraphic depths were dated by radiocarbon analysis, and centennial-scale dating was provided by short-lived radioisotope analysis conducted on two short cores. Grain size analysis was conducted on four cores, and pollen analysis on one core. These data are used to quantify current conditions in the marsh sediments and provide a history of local environmental change for the last three millennia. This data release archives the data, downloadable as Excel and CSV spreadsheets, and PDF and JPEG files.