Spatial distribution of hexachlorocyclohexane isomers in the Bering and Chukchi Sea Shelf ecosystem

The spatial distribution of fields for alpha and gamma hexachlorocyclohexanes are described for the Bering/Chukchi Shelf ecosystem. Fields for the surface concentration of these isomers are defined that closely match the water mass structure of this region. The relative abundances for the alpha and gamma isomers were also excellent markers for the prevailing currents here. Water type groupings based on the percentage differences from respective mean values for the alpha and gamma concentrations represented water zones that accurately depicted the Anadyr Current and a Siberian Coastal Front, which originates along the upper Chukchi Peninsula. Values for the alpha/gamma ratios ranged from a low of 2.52 for the Pacific Water inputs for this region to a high of 9.36 for the Siberian coastal current water. This study demonstrates the importance of using marker chemicals like HCHs to identify ocean currents.