26.11.2012: Biogeochemical Modelling Seminar

 10:00 Uhr, Seeburg Seminar Raum, Düsternbrooker Weg 2

Kontakt: Andreas Oschlies

Abstract:

Oceanic carbon sequestration plays an important role in limiting the rise of atmospheric CO₂ . Previous work suggests that the Arctic Ocean is an important sink of CO₂  relative to its size, but that its role is likely to be changing in uncertain ways as a result of global warming. In this talk, I will present the results of my work in which a conceptual box model of the Arctic Ocean was used to determine carbon sequestration in the region. Combining a recently developed, volume-conserved velocity field across the main ocean gateways (Davis Strait, Fram Strait, Barents Sea Opening and Bering Strait) with measurements of dissolved inorganic carbon (DIC) from the CARINA dataset, net DIC transport from the region was determined. By applying a carbon framework to reveal the origin of the DIC, the primary mechanisms contributing to net transport were also uncovered. The results suggest that 57±39 TgCyr^-1  is exported as DIC from the Arctic Ocean, beneath a mixed layer depth of 50m. This is largely due to a strong biological pump, observed in the export of 105±22 TgCyr^-1  as DIC that originated from the remineralisation of organic matter. It is suggested that present day DIC export is limited by the accumulation of carbon derived from human emissions, mainly imported in Atlantic Water. This work represents the most comprehensive, observation-based approach to understanding the Arctic Ocean’s role in carbon sequestration to date.