The Ross Sea. In: “Carbon and Nutrient Fluxes in Continental Margins: A Global Synthesis

We present budgets of carbon and nitrogen for the Ross Sea, Antarctica. The novelty of this study consists in estimating both vertical water column to sedimentary fluxes as well as horizontal exchanges due to water mass lateral transport between the continental shelf and the open ocean. The deep layer, the most relevant for the continental shelf pump, releases carbon to the deep ocean as dissolved inorganic carbon (937 Gmol), dissolved organic carbon (13 Gmol), and particulate organic carbon (7 Gmol). With regard to particulate organic nitrogen, less than 1 Gmol is released to the deep ocean, but the nitrogen balance becomes strongly positive considering the 19 Gmol imported from the open ocean. Our estimates indicate that during an average austral summer, the amount of matter recycled through biological and sedimentary processes within the Ross Sea is almost one order of magnitude higher than the amount exchanged with the open ocean.Within the upper layer 3486 and 523 Gmol of carbon and nitrogen, respectively, are incorporated into biomass, of which about 50% are later exported to the deep layer. Since the burial is negligible (less than 0.5%), considering the upper and deep layer together, we estimate that about 3155 Gmol of carbon and 473 Gmol of nitrogen are channelled to the higher trophic levels and to the dissolved organic pools. Thus, grazing becomes the most important export term in the Ross Sea.