Spatial distribution and fluorescence properties of dissolved organic matter in Chukchi and Beaufort Seas

Abstract

Concentration and fluorescence properties of dissolved organic matter were determined in the upper 200 m of Chukchi and Beaufort Seas during the summer. Significant negative correlations between concentration of dissolved organic carbon (DOC) and salinity were observed at both areas, but was much weaker in Chukchi Sea. The humic-like component identified by PARAFAC significantly increased together with salinity in Chukchi Sea. However, this correlation showed an opposite trend in Beaufort Sea. These results indicate that high level of labile dissolved organic matter (DOM) was related to freshwater sources in Chukchi Sea, whereas high level of refractory DOM was related to freshwater sources in Beaufort Sea. Overall, spatial distribution and characteristics of DOM seem strongly affected by freshwater discharge in this study region during the summer season. Furthermore, fluorescence properties of DOM can provide valuable information concerning the quality of DOM in freshwater sources at both areas.C) and salinity were observed at both areas, but was much weaker in Chukchi Sea. The humic-like component identified by PARAFAC significantly increased together with salinity in Chukchi Sea. However, this correlation showed an opposite trend in Beaufort Sea. These results indicate that high level of labile dissolved organic matter (DOM) was related to freshwater sources in Chukchi Sea, whereas high level of refractory DOM was related to freshwater sources in Beaufort Sea. Overall, spatial distribution and characteristics of DOM seem strongly affected by freshwater discharge in this study region during the summer season. Furthermore, fluorescence properties of DOM can provide valuable information concerning the quality of DOM in freshwater sources at both areas.