Robert Iles, Texas A&M University, Department of Oceanography, College Station, TX, United States, Steven Francis DiMarco, Geochemical and Environmental Research Group (GERG), College Station, TX, United States, Anthony Knap, Texas A&M University College Station, Geochemical and Environmental Research Group (GERG), College Station, TX, United States and Nan D Walker, Louisiana State University, Baton Rouge, LA, United States; LSU-Coastal Studies Institute, Baton Rouge, LA, United States