Environmental and chemical measurements, and coral calcification rates in Bermuda from 2010 to 2012

Modern reef-building corals sustain a wide range of ecosystem services because of their ability to build calcium carbonate reef systems. The influence of environmental variables on coral calcification rates has been extensively studied, but our understanding of their relative importance is limited by the absence of in situ observations and the ability to decouple the interactions between different properties. We show that temperature is the primary driver of coral colony (Porites astreoides and Diploria labyrinthiformis) and reef-scale calcification rates over a 2-year monitoring period from the Bermuda coral reef. On the basis of multimodel climate simulations (Coupled Model Intercomparison Project Phase 5) and assuming sufficient coral nutrition, our results suggest that P. astreoides and D. labyrinthiformis coral calcification rates in Bermuda could increase throughout the 21st century as a result of gradual warming predicted under a minimum CO2 emissions pathway [representative concentration pathway (RCP) 2.6] with positive 21st-century calcification rates potentially maintained under a reduced CO2 emissions pathway (RCP 4.5). These results highlight the potential benefits of rapid reductions in global anthropogenic CO2 emissions for 21st-century Bermuda coral reefs and the ecosystem services they provide.

造礁珊瑚（reef-building corals）凭借构建碳酸钙礁体系统的能力，可维系多种多样的生态系统服务功能。学界已针对环境变量对珊瑚钙化速率的影响开展了大量研究，但由于缺乏原位观测数据，且难以解耦不同环境参数间的相互作用，当前对各变量相对重要性的认知仍存在局限。本研究基于百慕大珊瑚礁为期2年的监测数据，发现温度是星孔珊瑚（Porites astreoides）与迷宫脑珊瑚（Diploria labyrinthiformis）的珊瑚群落及礁体尺度钙化速率的主要驱动因子。基于多模式气候模拟（耦合模式比较计划第五阶段，Coupled Model Intercomparison Project Phase 5）结果，并假设珊瑚营养供给充足，研究结果表明：在最低二氧化碳排放路径[典型浓度路径（representative concentration pathway, RCP）2.6]预测的逐步增温背景下，百慕大海域这两种珊瑚的钙化速率将在整个21世纪持续上升；而在较低二氧化碳排放路径（RCP 4.5）下，21世纪的珊瑚钙化速率有望维持正值。本研究结果凸显了快速削减全球人为二氧化碳排放，对21世纪百慕大珊瑚礁及其所提供的生态系统服务而言，具有潜在的积极效益。