MAIN DRIVERS OF SURFACE WATER SALINITY WITHIN THE NORTH INLET ESTUARY

Coastal marshes are important ecosystems that provide an array of ecosystem services. With increasing sea level these marshes may negatively be impacted. Salinity is one variable that influences production within marshes. Gaining a better understanding of the major parameters that influence salinity will provide a better understanding of how marshes may be impacted. Within the North Inlet estuary, located in South Carolina, a long term data set (between January 2009 and December 2012) of salinity, tidal height, wind speed and direction, precipitation and temperature was analyzed to determine how each of these variables influence salinity.

Salinity varied greatly between the study period with a minimum of 0.9 ppt and maximum at 39.6 ppt, with the majority of the values falling between 33.3 ppt and 36 ppt. Wind direction changed with seasons, north westerly winds dominated during the winter and south westerly winds dominated during the spring and summer. Tidal height varied on a semi-diurnal cycle, and there were periodic rain events. Water temperatures had a maximum (36.1 ˚C) during the summer and minimum (0.9 ˚C) during the winter.

Multiple regression analyses and Akaike Information Criteria revealed which variables had an influence on salinity, and which parameters had the largest influence. Tidal height and precipitation were the biggest predictors of salinity. Temperature, wind speed, and wind direction all also had an influence on salinity but to a lesser extent.