Seawater carbonate chemistry and population-specific vulnerability to ocean change in a multistressor environment

Variation in environmental conditions across a species' range can alter their responses to environmental change through local adaptation and acclimation. Evolutionary responses, however, may be challenged in ecosystems with tightly coupled environmental conditions, where changes in the covariance of environmental factors may make it more difficult for species to adapt to global change. Here, we conduct a 3-month-long mesocosm experiment and find evidence for local adaptation/acclimation in populations of red sea urchins, Mesocentrotus franciscanus, to multiple environmental drivers. Moreover, populations differ in their response to projected concurrent changes in pH, temperature, and dissolved oxygen. Our results highlight the potential for local adaptation/acclimation to multivariate environmental regimes but suggest that thresholds in responses to a single environmental variable, such as temperature, may be more important than changes to environmental covariance. Therefore, identifying physiological thresholds in key environmental drivers may be particularly useful for preserving biodiversity and ecosystem functioning.

物种分布范围内的环境条件异质性，可通过本地适应（local adaptation）与驯化（acclimation）改变其对环境变化的响应。然而，在环境条件紧密耦合的生态系统中，环境因子协方差的改变会加剧物种适应全球变化的难度，进而对物种的进化响应构成挑战。本研究开展了一项为期3个月的中型实验生态系统（mesocosm）实验，结果发现红海胆（Mesocentrotus franciscanus）种群对多种环境驱动因子存在本地适应/驯化的证据。此外，不同红海胆种群对预估的pH、温度与溶解氧协同变化的响应模式存在显著差异。本研究结果既凸显了种群对多变量环境体系实现本地适应/驯化的潜力，同时也表明，相较于环境协方差的改变，单一环境变量（如温度）的响应阈值或许更为关键。因此，明确关键环境驱动因子的生理阈值，对保护生物多样性与维持生态系统功能具有重要意义。