Tracing the transport of colored dissolved organic matter in water masses of the Southern Beaufort Sea: relationship with hydrographic characteristics

[摘要] Light absorption by colored dissolved organic matter (CDOM)[a_CDOM(λ)] plays an important role in the heat budget of theArctic Ocean, contributing to the recent decline in sea ice, as well as inbiogeochemical processes. We investigated a_CDOM(λ) in theSouthern Beaufort Sea where a significant amount of CDOM is delivered by theMackenzie River. In the surface layer, a_CDOM(440) showed a strong andnegative correlation with salinity, indicating strong river influence andconservative transport in the river plume. Below the mixed layer, a weak butpositive correlation between a_CDOM(440) and salinity was observed abovethe upper halocline, resulting from the effect of removal of CDOM due tobrine rejection and lateral intrusion of Pacific summer waters into theselayers. In contrast, the relationship was negative in the upper and thelower haloclines, suggesting these waters originated from Arctic coastalwaters. DOC concentrations in the surface layer were strongly correlatedwith a_CDOM(440) (r² = 0.97), suggesting that this value can beestimated in this area, using a_CDOM(440) that is retrieved usingsatellite ocean color data. Implications for estimation of DOCconcentrations in surface waters using ocean color remote sensing arediscussed.

[学科分类] 地球化学与岩石