British Antarctic Survey, Natural Environment Research Council, Cambridge, U.K.
Glob Chang Biol. 2017 Dec;23(12):5083-5091. doi: 10.1111/gcb.13772. Epub 2017 Jun 23.
One of the major climate-forced global changes has been white to blue to green; losses of sea ice extent in time and space around Arctic and West Antarctic seas has increased open water and the duration (though not magnitude) of phytoplankton blooms. Blueing of the poles has increases potential for heat absorption for positive feedback but conversely the longer phytoplankton blooms have increased carbon export to storage and sequestration by shelf benthos. However, ice shelf collapses and glacier retreat can calve more icebergs, and the increased open water allows icebergs more opportunities to scour the seabed, reducing zoobenthic blue carbon capture and storage. Here the size and variability in benthic blue carbon in mega and macrobenthos was assessed in time and space at Ryder and Marguerite bays of the West Antarctic Peninsula (WAP). In particular the influence of the duration of primary productivity and ice scour are investigated from the shallows to typical shelf depths of 500 m. Ice scour frequency dominated influence on benthic blue carbon at 5 m, to comparable with phytoplankton duration by 25 m depth. At 500 m only phytoplankton duration was significant and influential. WAP zoobenthos was calculated to generate ~10 , 4.5 × 10 and 1.6 × 10 tonnes per year (between 2002 and 2015) in terms of production, immobilization and sequestration of carbon respectively. Thus about 1% of annual primary productivity has sequestration potential at the end of the trophic cascade. Polar zoobenthic blue carbon capture and storage responses to sea ice losses, the largest negative feedback on climate change, has been underestimated despite some offsetting of gain by increased ice scouring with more open water. Equivalent survey of Arctic and sub-Antarctic shelves, for which new projects have started, should reveal the true extent of this feedback and how much its variability contributes to uncertainty in climate models.
其中一个主要的气候强迫全球变化是从白色变为蓝色再变为绿色；北极和西南极海域的海冰范围在时间和空间上的损失增加了开阔水域和浮游植物爆发的持续时间（尽管不是规模）。极地的变蓝增加了热量吸收的正反馈潜力，但相反，浮游植物爆发持续时间的延长增加了通过大陆架底栖生物向储存和封存的碳输出。然而，冰架崩塌和冰川后退会产生更多的冰山，而开阔水域则为冰山提供了更多的机会冲刷海底，减少了底栖生物蓝碳的捕获和储存。在这里，我们评估了西南极半岛（WAP）的赖德湾（Ryder Bay）和玛格丽特湾（Marguerite Bay）的大型和大型底栖生物的底栖蓝碳的大小和空间变异性。特别是，从浅水区到典型的 500 米大陆架深度，研究了初级生产力持续时间和冰冲刷的影响。在 5 米处，冰冲刷频率对底栖蓝碳的影响与浮游植物持续时间相当，到 25 米深处。在 500 米处，只有浮游植物持续时间具有重要影响。WAP 底栖生物估计每年产生约 10 、 4.5×10 和 1.6×10 吨的碳，分别用于生产、固定和封存。因此，在营养级联的末端，大约 1%的年初级生产力具有封存潜力。尽管由于更多开阔水域的冰冲刷而增加了一些增益，但对气候变化最大的负反馈——海冰损失对极地底栖生物蓝碳捕获和储存的反应一直被低估了。尽管已经开始了一些新的北极和亚南极大陆架的调查，但这些新的调查应该揭示这种反馈的真实程度，以及其变异性对气候模型不确定性的贡献有多大。
