Global change is impacting the oceans in an unprecedented way, and multiple lines of evidence suggest that species distributions are changing in space and time. There is increasing evidence that multiple environmental stressors act together to constrain species habitat more than expected from warming alone. Here, we conducted a comprehensive study of how temperature and aragonite saturation state act together to limit Limacina helicina, globally distributed pteropods that are ecologically important pelagic calcifiers and an indicator species for ocean change. We co-validated three different approaches to evaluate the impact of ocean warming and acidification (OWA) on the survival and distribution of this species in the California Current Ecosystem. First, we used colocated physical, chemical, and biological data from three large-scale west coast cruises and regional time series; second, we conducted multifactorial experimental incubations to evaluate how OWA impacts pteropod survival; and third, we validated the relationships we found against global distributions of pteropods and carbonate chemistry. OWA experimental work revealed mortality increases under OWA, while regional habitat suitability indices and global distributions of L. helicina suggest that a multi-stressor framework is essential for understanding pteropod distributions. In California Current Ecosystem habitats, where pteropods are living close to their thermal maximum already, additional warming and acidification through unabated fossil fuel emissions (RCP 8.5) are expected to dramatically reduce habitat suitability.

中文翻译：

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随着变暖和海洋酸化，中上层钙化生物面临死亡率增加和栖息地丧失

全球变化正在以前所未有的方式影响海洋，多条证据表明物种分布在空间和时间上正在发生变化。越来越多的证据表明，多种环境压力因素共同作用对物种栖息地的限制超过了单独变暖的预期。在这里，我们对温度和文石饱和状态如何共同作用以限制Limacina helicina进行了全面研究，全球分布的翼足类动物，它们是生态上重要的中上层钙化生物和海洋变化的指示物种。我们共同验证了三种不同的方法来评估海洋变暖和酸化 (OWA) 对该物种在加州海流生态系统中的生存和分布的影响。首先，我们使用了来自三个大型西海岸巡航和区域时间序列的物理、化学和生物数据；其次，我们进行了多因素实验孵化，以评估 OWA 如何影响翼足类动物的生存；第三，我们验证了我们发现的与翼足类动物和碳酸盐化学的全球分布的关系。OWA 实验工作显示，在 OWA 下死亡率增加，而L. helicina的区域栖息地适宜性指数和全球分布表明多压力源框架对于理解翼足类动物分布至关重要。在加利福尼亚当前的生态系统栖息地，翼足类动物的生活已经接近其最高温度，预计通过有增无减的化石燃料排放（RCP 8.5）造成的额外变暖和酸化将大大降低栖息地的适宜性。