Summer CDOM Opticla Properties in the Western Arctic Under Low Sea Ice Conditions

Abstract

The Chukchi Borderland and Mendeleev Ridge (CBMR) region of the Western Arctic Ocean with its complex topography is a region of confluence of different water masses that is alson undergoing rapid chnges in sea ice cover. In this study we report on the dissolved orgarnic carbon (DOC) concentrations and chromophoric dissolved orgarnic matter (CDOM) optical properties of absorption and fluorescence in the CBLMR region during the summer of 2112 when the extent of arctic sea ice was the lowest recorded. Mean DOC concentrations for all the stations sampled were 133.24±32.50 uMol and varied over the range 47.91-248.10 uMol. The mean absorption coefficient at 355nm was 0.361±0.282 /m, and varied from 0.053 to 2.03/m with the highest values in the Arctic Basin. The spectral slope in surface water was relatively high in comparison to subsurface waters, suggesting CDOM photodegradation. PARAFAC analysis of excitation-emission matrix (EEMs) fluorescence identified two humic-like and two protein-like components. Sparial variability of CDOM optical properties and relationships to salinity and temperature will be examined for the CBLMR region of the Arctic Ocean.