Hawaii Coastal Seawater CO2 Network: A Statistical Evaluation of a Decade of Observations on Tropical Coral Reefs
Hawaii Coastal Seawater CO2 Network: A Statistical Evaluation of a Decade of Observations on Tropical Coral Reefs
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DOI：
10.3389/fmars.2019.00226
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发表时间：
2019-05
影响因子：
3.7
通讯作者：
G. Terlouw;Lucie A. C. M. Knor;E. H. De Carlo;P. Drupp;F. Mackenzie;Y. Li;A. Sutton;A. Plueddemann;C. Sabine
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文献类型：
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作者：
G. Terlouw;Lucie A. C. M. Knor;E. H. De Carlo;P. Drupp;F. Mackenzie;Y. Li;A. Sutton;A. Plueddemann;C. Sabine
对夏威夷O‘ahu周围沿海系泊地收集的近十年高分辨率表层海水二氧化碳分压(PCO2)时间序列数据的统计评估表明，这些珊瑚礁生态系统在2008年至2016年期间主要是大气中二氧化碳的净来源。最大的海气通量(1.2 4±0.33molm-2yr-1)和最大的海水二氧化碳变率(95 0μ大气总范围或8倍于公海范围)出现在靠近卡内奥荷湾浅滩珊瑚礁系统的CRIMP-2站点。南岸的两个站点，Kilo Nalu和Ala Wai，也表现出大约两倍于公海的地表水二氧化碳变化量，但净通量比CRIMP-2的强钙化系统更接近公海。所有系泊地点都表现出与大气相反的季节循环，夏季最高，冬季较低。在CRIMP-2和Kilo Nalu站点，沿海的平均日变化分别从最高的192微米/天到最低的32微米/天不等，比在公海站点观测到的高出一到两个数量级。在这里，我们研究了不同沿海地区的变化模式和驱动因素。尽管二氧化碳通量和海-气二氧化碳通量的日变化和季节变化受到局地过程的强烈影响，但盆地尺度的气候振荡也影响年际时间尺度上的变化。
A statistical evaluation of nearly ten years of high-resolution surface seawater carbon dioxide partial pressure (pCO2) time-series data collected from coastal moorings around O’ahu, Hawai’i suggest that these coral reef ecosystems were largely a net source of CO2 to the atmosphere between 2008 and 2016. The largest air-sea flux (1.24 ± 0.33 mol m-2 yr-1) and the largest variability in seawater pCO2 (950 μatm overall range or 8x the open ocean range) were observed at the CRIMP-2 site, near a shallow barrier coral reef system in Kaneohe Bay O’ahu. Two south shore sites, Kilo Nalu and Ala Wai, also exhibited about twice the surface water pCO2 variability of the open ocean, but had net fluxes that were much closer to the open ocean than the strongly calcifying system at CRIMP-2. All mooring sites showed the opposite seasonal cycle from the atmosphere, with the highest values in the summer and lower values in the winter. Average coastal diurnal variabilities ranged from a high of 192 µatm/day to a low of 32 µatm/day at the CRIMP-2 and Kilo Nalu sites, respectively, which is one to two orders of magnitude greater than observed at the open ocean site. Here we examine the modes and drivers of variability at the different coastal sites. Although daily to seasonal variations in pCO2 and air-sea CO2 fluxes are strongly affected by localized processes, basin-scale climate oscillations also affect the variability on interannual time scales.