Gas exchange of CO2 and O2 in partially ice-covered regions of the Arctic Ocean investigated using in situ sensors

7th International Symposium on Gas Transfer at Water Surfaces

Islam, F.^1 ; DeGrandpre, M.^1 ; Beatty, C.^1 ; Krishfield, R.^1 ; Toole, J.^2

Department of Chemistry and Biochemistry, University of Montana, Missoula

MT, United States^1

Woods Hole Oceanographic Institution, Woods Hole

MA, United States^2

关键词: Atmospheric saturation;    Carbon cycles;    Gas exchange;    Gas exchange rate;    In-situ sensors;    Multi-year ices;    Ocean acidifications;    Time-series data;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/35/1/012018/pdf
DOI  :  10.1088/1755-1315/35/1/012018

来源: IOP

【 摘 要 】

Sea surface CO2dynamics are not well characterized in the Arctic Ocean (AO). Most data are from ship-based studies during the low-ice period (MaySeptember) and obtained from near shore areas because of accessibility. More CO2data are needed to improve models for predicting the future of the carbon cycle in the region and its relationship to ocean acidification. Air-sea gas exchange rates are complicated by the presence of ice. Consequently gas exchange rates have a larger uncertainty in the AO compared to other ocean regions. To provide more information about CO2dynamics and gas exchange in the AO, in situ time-series data have been collected from the Canada Basin during late summer to autumn of 2012. Partial pressure of CO2(pCO2), dissolved O2(DO) concentration, temperature, and salinity were measured at ∼6-m depth under little ice and multi-year ice on two ice-tethered profilers (ITPs) for 4050 days. The pCO2levels were always below atmospheric saturation whereas DO was almost always slightly above saturation. Although the two ITPs were on an average only 222 km apart, one was further south and had 14 ±?12% ice cover; whereas the more northern ITP had 63 ±?16% ice cover. Consequently the two data sets differed significantly in external forcings. Modeled variability of CO2and DO estimate that gas exchange would significantly alter sea surface pCO2in the low ice cover record but minimally in the more extensively ice-covered region. If these conditions extended over the entire AO, the total uptake of atmospheric CO2would be 28.6 Tg C yr-1and 15.4 Tg C yr-1under low and high ice-covered conditions, respectively.