Extensive dissolution of live pteropods in the Southern Ocean
Extensive dissolution of live pteropods in the Southern Ocean
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DOI：
10.1038/ngeo1635
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发表时间：
2012-12-01
影响因子：
18.3
通讯作者：
Murphy, E. J.
中科院分区：
文献类型：
--
作者：
Bednarsek, N.;Tarling, G. A.;Murphy, E. J.
由于人类活动导致海洋酸化，表层海洋的碳酸盐化学性质正在迅速变化(1)。在南大洋的上层，文石（一种具有快速溶解动力学的亚稳态碳酸钙）到 2050 年可能会变得不饱和（参考文献 2）。文石欠饱和可能会影响文石壳生物，这些生物在极地地区的地表水群落中占主导地位(3)。在这里，我们对 2008 年初从南大洋提取的活体翼足类 Limacina helicina antarctica 标本进行了分析。我们从水体顶部 200 米处采样，文石饱和度约为 1，因为上升的深水与含有人为二氧化碳的地表水混合。在扫描电子显微镜下将壳结构与其他文石过饱和区域的样品进行比较，我们发现仅在不饱和区域就有严重水平的壳溶解。根据实验室对具有一定文石饱和度水平的完整样品的孵化，文石饱和度为 0.94-1.12 的情况下孵化八天可产生同等水平的溶解。由于人类活动可能导致深水上升流和地表水吸收二氧化碳增加(2,4)，因此我们得出结论，文石壳生物受溶解影响的上层海洋区域可能会扩大。
The carbonate chemistry of the surface ocean is rapidly changing with ocean acidification, a result of human activities(1). In the upper layers of the Southern Ocean, aragonite-a metastable form of calcium carbonate with rapid dissolution kinetics-may become undersaturated by 2050 (ref. 2). Aragonite undersaturation is likely to affect aragonite-shelled organisms, which can dominate surface water communities in polar regions(3). Here we present analyses of specimens of the pteropod Limacina helicina antarctica that were extracted live from the Southern Ocean early in 2008. We sampled from the top 200 m of the water column, where aragonite saturation levels were around 1, as upwelled deep water is mixed with surface water containing anthropogenic CO2. Comparing the shell structure with samples from aragonite-supersaturated regions elsewhere under a scanning electron microscope, we found severe levels of shell dissolution in the undersaturated region alone. According to laboratory incubations of intact samples with a range of aragonite saturation levels, eight days of incubation in aragonite saturation levels of 0.94-1.12 produces equivalent levels of dissolution. As deep-water upwelling and CO2 absorption by surface waters is likely to increase as a result of human activities(2,4), we conclude that upper ocean regions where aragonite-shelled organisms are affected by dissolution are likely to expand.