Centre for Isotope Research, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Postfach 120161, 27515 Bremerhaven, Germany.
Philos Trans A Math Phys Eng Sci. 2014 Jul 13;372(2019):20130056. doi: 10.1098/rsta.2013.0056.
Data are presented for total carbon dioxide (TCO2), oxygen and nutrients from 14 cruises covering two repeat sections across the Weddell Gyre, from 1973 to 2010. Assessments of the rate of increase in anthropogenic CO2 (Cant) are made at three locations. Along the Prime Meridian, TCO2 is observed to steadily increase in the bottom water. Accompanying changes in silicate, nitrate and oxygen confirm the non-steady state of the Weddell circulation. The rate of increase in TCO2 of +0.12±0.05 μmol kg(-1) yr(-1) therefore poses an upper limit to the rate of increase in Cant. By contrast, the bottom water located in the central Weddell Sea exhibits no significant increase in TCO2, suggesting that this water is less well ventilated at the southern margins of the Weddell Sea. At the tip of the Antarctic Peninsula (i.e. the formation region of the bottom water found at the Prime Meridian), the high rate of increase in TCO2 over time observed at the lowest temperatures suggests that nearly full equilibration occurs with the anthropogenic CO2 of the atmosphere. This observation constitutes rare evidence for the possibility that ice cover is not a major impediment for uptake of Cant in this prominent deep water formation region.
提供了 1973 年至 2010 年期间 14 次穿越威德尔环流的总二氧化碳（TCO2）、氧气和营养物的观测数据，这些数据覆盖了两个重复区域。在三个地点评估了人为 CO2（Cant）的增长率。在本初子午线，底层水中 TCO2 稳定增加。硅酸盐、硝酸盐和氧气的伴随变化证实了威德尔环流的非稳态。因此，TCO2 增长率为+0.12±0.05μmol kg(-1)yr(-1)，这是 Cant 增长率的上限。相比之下，位于威德尔海中部的底层水 TCO2 没有明显增加，这表明该水在威德尔海的南部边缘通风不良。在南极半岛的尖端（即本初子午线处底层水的形成区域），观察到最低温度下 TCO2 的增长率很高，这表明与大气中的人为 CO2 几乎完全达到平衡。这一观察结果构成了一个罕见的证据，表明在这个著名的深水形成区域，冰盖并不是吸收 Cant 的主要障碍。
