SOIL HYDRO-GEOCHEMISTRY AND CRAYFISH DISTRIBUTION

The characteristic of borrowing crayfish habitats on US barrier islands is an area of promising research. This is a subject area that has not been well studied. In order to fill in this gap, this study investigates soil properties associated with a primary burrowing crayfish population on Sapelo Island, Georgia. Although not much is known about borrowing crayfish, literature review has shown that they are most commonly found in clay or silty-clay soils. To date only one site on Sapelo Island has a confirmed population of burrowing crayfish, even though there are many other sites that appear physically suitable for crayfish. For this study, soil samples were collected from this and other sites on the island. Soils were obtained using shovels and soil hand augers. To understand soil characteristics associated with the crayfish, an evaluation of the general soil properties was conducted using the SoilWeb survey application in Google Earth. These data were then used for site comparison together with results from laboratory analyses, which utilized a Munsell Color Book, an oven for drying, and a standard sieve set. The hydraulic conductively (K) values of the soils were estimated using falling head permeameters and slug tests. Approximately 5 g of oven-dried soil from each sample was used to extract nutrients and metals using 60 mL of LaMotte Universal Solvent and the Ahlstrom qualitative filter paper. The soil filtrate was analyzed for macronutrients (nitrate, potassium, phosphate, ferric iron, magnesium, sulfate, and calcium). Geochemical analysis of the soils was also carried out using X-Ray Fluorescence spectrometry while water physiochemical parameters (DO, temperature, conductivity and pH) were obtained using a YSI probe in the field. The soils were all well sorted with K-values ranging from 8 * 10 ^-3 to 1.2 *10^-2 cm/s. Nitrate concentrations were identical among the sites (about 5 ppm). Potassium varied among the sites, but the concentrations all fell within the same range. There was a difference in total iron and total phosphorus between the crayfish site and the other sites. The main driver of crayfish location at Sapelo Island appears to be salinity.