Summer CDOM optical properties in the western arctic under low sea ice conditions

Abstract

Dissolved organic matter (DOM) constitutes the largest pool of reduced organic carbon in the ocean and plays an important part in the global carbon cycle. The Arctic Ocean, with about 1% of the global ocean volume receives about 10% of the global river discharge. Under climate change, increased discharge from the Arctic rivers could significantly affect the carbon cycle in the Arctic Ocean. The colored or chromophoric DOM or CDOM is the fraction of DOM that absorbs light in the ultraviolet and visible wavelength and is a major light absorbing constituent in the ocean that influences light penetration and thus biological productivity. Through its influence on the water leaving radiance or the light field it also affects satellite ocean color chlorophyll algorithms. CDOM also fluoresces and its fluorescence properties have been studied using excitation-emission matrix spectroscopy (EEMs). The fluorescent constituents of DOM can include humic and protein substances (Coble 1996; 1997; Mopper and Schultz 1993). Humic substances are mostly of terrestrial origin, but humic-like fluorescent material of marine origin is also present in aquatic systems (Coble 2007).