LAUSR

The phytoplankton bloom in the Ross Sea is the largest in spatial extent and one of the most productive in Antarctica, yet the fate of the summer bloom remains poorly understood. Here we present carbon system data from the first biogeochemical process cruise to be conducted in both the western and central Ross Sea during late summer (February–March 2013). Using one-dimensional carbon budgets, we found evidence for substantial positive net community production (425 ± 204 mmol C m−2 d−1) during the late summer in Terra Nova Bay (TNB) of the western Ross Sea, which was rapidly exported to below 200 m. In addition, seasonally integrated carbon export was higher in diatom-dominated TNB (7.3 ± 0.9 mol C m−2) compared to the Phaeocystis antarctica-dominated central Ross Sea (3.4 ± 0.8 mol C m−2). Substantial late summer productivity and export may be a widespread phenomenon in Antarctic coastal regions that is not accounted for in regional carbon models.