Spatial variability of surface pCO2 and air-sea CO2 flux in the Amundsen Sea Polynya, Antarctica

• DOI: 10.12952/journal.elementa.000036
• Publication Date: 2014-12-11T15:16:32Z
• Authors: L. Mu; S. E. Stammerjohn; K. E. Lowry; P. L. Yager
• Keywords: Sink (geography)

Abstract Partial pressure of CO2 (pCO2) and dissolved oxygen (DO) in the surface waters Amundsen Sea Polynya (ASP) were measured during austral summer 2010–2011 on International Research Expedition (ASPIRE). Surface pCO2 central polynya was as low 130 µatm, mainly due to strong net primary production. Comparing saturation states DO distinguished dominant factors (biological activity, temperature, upwelling, ice melt) controlling across regions. Air-sea flux, estimated using average shipboard winds, showed high spatial variability (-52 25 mmol C m-2 d-1) related these factors. The region exhibited a flux -36 ± 8.4 d-1, which is ∼ 50% larger than that reported for peak bloom well-studied Ross Sea, comparable rates Chukchi significantly higher most continental shelves around world. This (∼ 20,000 km2) accounted 85% uptake entire open water area. Margins with lower algal biomass 15% regional carbon uptake, likely resulting from reductions by sea melt. During ASPIRE we also observed up 490 µatm small near Dotson Ice Shelf an efflux 11 5.4 d-1 offset about 3% much region. Overall, ASP large sink atmospheric spatially averaged density -18 14 d-1. suggests disproportionate influence Southern Ocean. Since has experienced significant increase duration (1979–2013), speculate whether this will future climate-driven change.