Organic carbon and colloids in the Mackenzie River and Beaufort Sea

Photo-oxidation analysis of colloidal organic material from the Mackenzie River and Beaufort Sea indicates that organic colloids in riverine, brackish, and marine waters match organic particulate material in magnitude and distribution. Comparison with data obtained by CHN analysis of organic colloids g > 0.2 μm in size indicates that most of the riverine organic colloidal material resides in the < 0.2 μm to low nm size range. The colloidal fraction is significant in the Mackenzie River, but does not play a major role in the mass balance of total organic carbon in the Mackenzie River and Beaufort Sea. We recognize recent controversy regarding the analysis of marine dissolved organic carbon and suggest that such controversy may not apply to data obtained from freshwater environments.