Dissolution dominating calcification process in polar pteropods close to the point of aragonite undersaturation.
Dissolution dominating calcification process in polar pteropods close to the point of aragonite undersaturation.
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DOI：
10.1371/journal.pone.0109183
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发表时间：
2014
期刊：
影响因子：
3.7
通讯作者：
Feely RA
中科院分区：
文献类型：
--
作者：
Bednaršek N;Tarling GA;Bakker DC;Fielding S;Feely RA
翼足类是海洋上层丰富的浮游动物，它们能建造文石外壳。海洋酸化导致表层的文石饱和度降低，几项培养研究表明，这些生物体的钙化率因此降低。本研究提供了一个特定重量的净钙化率函数，包括溶解和钙化率在一个合理的未来文石饱和状态（Ωar）的范围内。我们测量了总溶解在翼足类Limacina helicina anapartica在斯科舍海（南大洋）通过孵育活标本在一系列的文石饱和状态最多14天。样品在暴露于欠饱和条件（Ωar ≤ 0.8）后几乎立即开始溶解，每天损失1.4%的壳质量。观察到的总溶解速率与文石溶解速率定律动力学预测的速率不同，在Ωar水平略高于1时较高，在Ωar水平为1至0.8时较低。这表明，壳体质量甚至受到过渡饱和度的影响，但是，尽管如此，在欠饱和条件下，仍有一些保护壳体的部分措施。将根据当前观察结果得出的总溶解对Ωar的函数与通过不同研究得出的总钙化的函数进行比较，结果表明，即使在Ωar接近1的水平下，溶解也成为主要过程，净壳生长在Ωar为1.03时停止。总溶解越来越占主导地位的壳质量的净变化，饱和度低于1。除了影响它们的生存能力外，翼足类外壳在表层的这种溶解将导致下沉速度减慢，并减少碳和碳酸盐流入深海。
Thecosome pteropods are abundant upper-ocean zooplankton that build aragonite shells. Ocean acidification results in the lowering of aragonite saturation levels in the surface layers, and several incubation studies have shown that rates of calcification in these organisms decrease as a result. This study provides a weight-specific net calcification rate function for thecosome pteropods that includes both rates of dissolution and calcification over a range of plausible future aragonite saturation states (Ωar). We measured gross dissolution in the pteropod Limacina helicina antarctica in the Scotia Sea (Southern Ocean) by incubating living specimens across a range of aragonite saturation states for a maximum of 14 days. Specimens started dissolving almost immediately upon exposure to undersaturated conditions (Ωar∼0.8), losing 1.4% of shell mass per day. The observed rate of gross dissolution was different from that predicted by rate law kinetics of aragonite dissolution, in being higher at Ωar levels slightly above 1 and lower at Ωar levels of between 1 and 0.8. This indicates that shell mass is affected by even transitional levels of saturation, but there is, nevertheless, some partial means of protection for shells when in undersaturated conditions. A function for gross dissolution against Ωar derived from the present observations was compared to a function for gross calcification derived by a different study, and showed that dissolution became the dominating process even at Ωar levels close to 1, with net shell growth ceasing at an Ωar of 1.03. Gross dissolution increasingly dominated net change in shell mass as saturation levels decreased below 1. As well as influencing their viability, such dissolution of pteropod shells in the surface layers will result in slower sinking velocities and decreased carbon and carbonate fluxes to the deep ocean.
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影响因子：
5.2
作者：
FEELY, RA;CHEN, CTA
通讯作者：
CHEN, CTA
影响因子：
0.5
作者：
FABRY, VJ
通讯作者：
FABRY, VJ
影响因子：
56.9
作者：
BERNER, RA;HONJO, S
通讯作者：
HONJO, S
影响因子：
56.9
作者：
Feely, RA;Sabine, CL;Millero, FJ
通讯作者：
Millero, FJ
影响因子：
18.3
作者：
Bednarsek, N.;Tarling, G. A.;Murphy, E. J.
通讯作者：
Murphy, E. J.