Seawater carbonate chemistry and fish communities properties off CO2 seeps in Japan

Ocean acidification will likely change the structure and function of coastal marine ecosystems over coming decades. Volcanic carbon dioxide seeps generate dissolved CO2 and pH gradients that provide realistic insights into the direction and magnitude of these changes. Here, we used fish and benthic community surveys to assess the spatio-temporal dynamics of fish community properties off CO2 seeps in Japan. Adding to previous evidence from ocean acidification ecosystem studies conducted elsewhere, our findings documented shifts from calcified to non-calcified habitats with reduced benthic complexity. In addition, we found that such habitat transition led to decreased diversity of associated fish and to selection of those fish species better adapted to simplified ecosystems dominated by algae. Our data suggest that near-future projected ocean acidification levels will oppose the ongoing range expansion of coral reef-associated fish due to global warming.

在未来数十年间，海洋酸化（Ocean Acidification）大概率会改变近岸海洋生态系统的结构与功能。火山二氧化碳喷口（Volcanic Carbon Dioxide Seeps）会产生溶解态二氧化碳与pH梯度，为理解这类变化的方向与幅度提供了贴近现实的研究视角。本研究通过鱼类与底栖生物群落调查，评估了日本近海二氧化碳喷口区鱼类群落特征的时空动态。结合此前其他地区海洋酸化生态系统研究的已有证据，本研究结果显示，生态系统出现了从钙化生境向非钙化生境的转变，且底栖生物复杂度随之降低。此外，本研究还发现，这类生境转变会导致伴生鱼类的多样性下降，并筛选出更适应藻类主导的简化生态系统的鱼类物种。本研究数据表明，未来预计的海洋酸化水平，会抵消因全球变暖而持续进行的珊瑚礁伴生鱼类的分布范围扩张。