State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, China.
Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA.
Glob Chang Biol. 2018 Jul;24(7):3055-3064. doi: 10.1111/gcb.14065. Epub 2018 Feb 19.
Coccolithophores are important oceanic primary producers not only in terms of photosynthesis but also because they produce calcite plates called coccoliths. Ongoing ocean acidification associated with changing seawater carbonate chemistry may impair calcification and other metabolic functions in coccolithophores. While short-term ocean acidification effects on calcification and other properties have been examined in a variety of coccolithophore species, long-term adaptive responses have scarcely been documented, other than for the single species Emiliania huxleyi. Here, we investigated the effects of ocean acidification on another ecologically important coccolithophore species, Gephyrocapsa oceanica, following 1,000 generations of growth under elevated CO conditions (1,000 μatm). High CO -selected populations exhibited reduced growth rates and enhanced particulate organic carbon (POC) and nitrogen (PON) production, relative to populations selected under ambient CO (400 μatm). Particulate inorganic carbon (PIC) and PIC/POC ratios decreased progressively throughout the selection period in high CO -selected cell lines. All of these trait changes persisted when high CO -grown populations were moved back to ambient CO conditions for about 10 generations. The results suggest that the calcification of some coccolithophores may be more heavily impaired by ocean acidification than previously predicted based on short-term studies, with potentially large implications for the ocean's carbon cycle under accelerating anthropogenic influences.
颗石藻不仅在光合作用方面，而且在产生称为颗石的方解石板方面，都是重要的海洋初级生产者。与海水碳酸盐化学变化相关的持续海洋酸化可能会损害颗石藻的钙化和其他代谢功能。虽然已经在各种颗石藻物种中研究了短期海洋酸化对钙化和其他特性的影响，但除了单一物种 Emiliania huxleyi 之外，几乎没有记录长期的适应反应。在这里，我们研究了海洋酸化对另一种生态重要的颗石藻物种 Gephyrocapsa oceanica 的影响，在高 CO 条件（1000 μatm）下生长了 1000 代。与在环境 CO（400 μatm）下选择的种群相比，高 CO 选择的种群表现出生长速率降低，以及颗粒有机碳（POC）和氮（PON）产量增加。在高 CO 选择的细胞系中，整个选择期内颗粒无机碳（PIC）和 PIC/POC 比值逐渐降低。当高 CO 生长的种群移回环境 CO 条件约 10 代时，所有这些性状变化都持续存在。结果表明，与基于短期研究的预测相比，海洋酸化可能会更严重地损害某些颗石藻的钙化作用，这对加速人为影响下海洋碳循环可能产生重大影响。
