Cyronak Tyler, Andersson Andreas J, Langdon Chris, Albright Rebecca, Bates Nicholas R, Caldeira Ken, Carlton Renee, Corredor Jorge E, Dunbar Rob B, Enochs Ian, Erez Jonathan, Eyre Bradley D, Gattuso Jean-Pierre, Gledhill Dwight, Kayanne Hajime, Kline David I, Koweek David A, Lantz Coulson, Lazar Boaz, Manzello Derek, McMahon Ashly, Meléndez Melissa, Page Heather N, Santos Isaac R, Schulz Kai G, Shaw Emily, Silverman Jacob, Suzuki Atsushi, Teneva Lida, Watanabe Atsushi, Yamamoto Shoji
Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, United States of America.
The Rosential School of Marine & Atmospheric Science, University of Miami, Miami, Florida, United States of America.
PLoS One. 2018 Jan 9;13(1):e0190872. doi: 10.1371/journal.pone.0190872. eCollection 2018.
Worldwide, coral reef ecosystems are experiencing increasing pressure from a variety of anthropogenic perturbations including ocean warming and acidification, increased sedimentation, eutrophication, and overfishing, which could shift reefs to a condition of net calcium carbonate (CaCO3) dissolution and erosion. Herein, we determine the net calcification potential and the relative balance of net organic carbon metabolism (net community production; NCP) and net inorganic carbon metabolism (net community calcification; NCC) within 23 coral reef locations across the globe. In light of these results, we consider the suitability of using these two metrics developed from total alkalinity (TA) and dissolved inorganic carbon (DIC) measurements collected on different spatiotemporal scales to monitor coral reef biogeochemistry under anthropogenic change. All reefs in this study were net calcifying for the majority of observations as inferred from alkalinity depletion relative to offshore, although occasional observations of net dissolution occurred at most locations. However, reefs with lower net calcification potential (i.e., lower TA depletion) could shift towards net dissolution sooner than reefs with a higher potential. The percent influence of organic carbon fluxes on total changes in dissolved inorganic carbon (DIC) (i.e., NCP compared to the sum of NCP and NCC) ranged from 32% to 88% and reflected inherent biogeochemical differences between reefs. Reefs with the largest relative percentage of NCP experienced the largest variability in seawater pH for a given change in DIC, which is directly related to the reefs ability to elevate or suppress local pH relative to the open ocean. This work highlights the value of measuring coral reef carbonate chemistry when evaluating their susceptibility to ongoing global environmental change and offers a baseline from which to guide future conservation efforts aimed at preserving these valuable ecosystems.
在全球范围内，珊瑚礁生态系统正面临着来自各种人为干扰的日益增加的压力，包括海洋变暖和酸化、沉积物增加、富营养化和过度捕捞，这些都可能使珊瑚礁转变为碳酸钙（CaCO₃）净溶解和侵蚀的状态。在此，我们确定了全球23个珊瑚礁区域内的净钙化潜力以及净有机碳代谢（净群落生产力；NCP）和净无机碳代谢（净群落钙化；NCC）的相对平衡。鉴于这些结果，我们考虑使用根据在不同时空尺度上收集的总碱度（TA）和溶解无机碳（DIC）测量值得出的这两个指标来监测人为变化下珊瑚礁生物地球化学的适用性。根据相对于近海碱度消耗推断，本研究中的所有珊瑚礁在大多数观测中都是净钙化的，尽管在大多数地点偶尔会出现净溶解的观测结果。然而，净钙化潜力较低（即TA消耗较低）的珊瑚礁可能比潜力较高的珊瑚礁更早转向净溶解状态。有机碳通量对溶解无机碳（DIC）总变化的影响百分比（即NCP与NCP和NCC之和的比值）在32%至88%之间，反映了珊瑚礁之间固有的生物地球化学差异。对于给定的DIC变化，NCP相对百分比最大的珊瑚礁海水pH值变化最大，这与珊瑚礁相对于开阔海洋提高或抑制局部pH值的能力直接相关。这项工作突出了在评估珊瑚礁对当前全球环境变化的敏感性时测量其碳酸盐化学的价值，并提供了一个基线，以指导未来旨在保护这些宝贵生态系统的保护工作。
