Department of Zoology, University of British Columbia, Vancouver, Canada.
Department of Ecoscience - Marine Ecology & Arctic Research Centre, Aarhus University, Aarhus C, Denmark.
Elife. 2023 Apr 11;12:e81080. doi: 10.7554/eLife.81080.
Ongoing climate change has caused rapidly increasing temperatures and an unprecedented decline in seawater pH, known as ocean acidification. Increasing temperatures are redistributing species toward higher and cooler latitudes that are most affected by ocean acidification. While the persistence of intertidal species in cold environments is related to their capacity to resist sub-zero air temperatures, studies have never considered the interacting impacts of ocean acidification and freeze stress on species survival and distribution. Here, a full-factorial experiment was used to study whether ocean acidification increases mortality in subtidal and subtidal . , and intertidal following sub-zero air temperature exposure. We examined physiological processes behind variation in freeze tolerance using H NMR metabolomics, analyses of fatty acids, and amino acid composition. We show that low pH conditions (pH = 7.5) significantly decrease freeze tolerance in both intertidal and subtidal populations of spp. Under current day pH conditions (pH = 7.9), intertidal was more freeze tolerant than subtidal and subtidal . Conversely, under low pH conditions, subtidal was more freeze tolerant than the other mussel categories. Differences in the concentration of various metabolites (cryoprotectants) or in the composition of amino acids and fatty acids could not explain the decrease in survival. These results suggest that ocean acidification can offset the poleward range expansions facilitated by warming and that reduced freeze tolerance could result in a range contraction if temperatures become lethal at the equatorward edge.
持续的气候变化导致了温度的快速升高和海水 pH 值的空前下降，即海洋酸化。温度升高正在将物种重新分布到受海洋酸化影响最大的高纬度和更冷的地区。虽然潮间带物种在寒冷环境中的生存与它们抵抗零下气温的能力有关，但研究从未考虑过海洋酸化和冻结应激对物种生存和分布的相互影响。在这里，我们采用完全因子实验来研究海洋酸化是否会增加亚潮带和潮下带物种在暴露于零下气温后的死亡率。我们使用 NMR 代谢组学、脂肪酸分析和氨基酸组成来研究耐冻结性变化背后的生理过程。我们表明，在低 pH 值条件下（pH = 7.5），亚潮带和潮下带的 spp. 的耐冻结能力显著降低。在当前的 pH 值条件下（pH = 7.9），潮间带 比亚潮带和潮下带的耐冻结能力更强。相反，在低 pH 值条件下，亚潮带的耐冻结能力强于其他贻贝种类。各种代谢物（防冻剂）的浓度或氨基酸和脂肪酸组成的差异不能解释存活率的下降。这些结果表明，海洋酸化可以抵消变暖带来的极向范围扩张，如果温度在赤道边缘变得致命，耐冻结能力的降低可能导致范围收缩。
