Seawater carbonate chemistry and calcification during tropical reef studies at Moorea (French Polynesia), 1997

Community metabolism and air-sea carbon dioxide (CO2) fluxes were investigated in July 1992 on a fringing reef at Moorea (French Polynesia). The benthic community was dominated by macroalgae (85% substratum cover) and comprised of Phaeophyceae Padina tenuis (Bory), Turbinaria ornata (Turner) J. Agardh, and Hydroclathrus clathratus Bory (Howe); Chlorophyta Halimeda incrassata f. ovata J. Agardh (Howe); and Ventricaria ventricosa J. Agardh (Olsen et West), as well as several Rhodophyta (Actinotrichia fragilis Forskál (Børgesen) and several species of encrusting coralline algae). Algal biomass was 171 g dry weight/m**2. Community gross production (Pg), respiration (R), and net calcification (G) were measured in an open-top enclosure. Pg and R were respectively 248 and 240 mmol Co2/m**2/d, and there was a slight net dissolution of CaCO3 (0.8 mmol/m**2/d). This site was a sink for atmospheric CO2 (10 ± 4 mmol CO2/m**2/d), and the analysis of data from the literature suggests that this is a general feature of algal-dominated reefs. Measurement of air-sea CO2 fluxes in open water close to the enclosure demonstrated that changes in small-scale hydrodynamics can lead to misleading conclusions. Net CO2 evasion to the atmosphere was measured on the fringing reef due to changes in the current pattern that drove water from the barrier reef (a C02 source) to the study site.

1992年7月，研究者针对法属波利尼西亚茉莉雅岛的一处岸礁（fringing reef）开展了群落代谢与海-气二氧化碳（CO₂）通量的调查研究。该研究区域的底栖群落以大型藻类（macroalgae）为优势类群，基质覆盖率达85%，类群涵盖褐藻门（Phaeophyceae）的*Padina tenuis* (Bory)、*Turbinaria ornata* (Turner) J. Agardh、*Hydroclathrus clathratus* Bory (Howe)；绿藻门（Chlorophyta）的*Halimeda incrassata* f. *ovata* J. Agardh (Howe)、*Ventricaria ventricosa* J. Agardh (Olsen et West)；以及多种红藻门（Rhodophyta）类群，包括*Actinotrichia fragilis* Forskál (Børgesen) 与多种壳状珊瑚藻（encrusting coralline algae）。藻类生物量为171 g干重/m²。研究通过敞顶培养箱（open-top enclosure）测定了群落总生产量（Pg）、呼吸作用（R）与净钙化作用（G）。结果显示，总生产量与呼吸作用分别为248与240 mmol CO₂/m²/d，同时伴随轻微的碳酸钙（CaCO₃）净溶蚀（0.8 mmol/m²/d）。该研究站点为大气CO₂的汇，通量为10±4 mmol CO₂/m²/d；结合文献数据分析可知，大型藻类占优的珊瑚礁普遍具备这一特征。对培养箱附近开阔水域的海-气CO₂通量测定结果表明，小尺度水动力（small-scale hydrodynamics）的变化可能导致研究结论出现偏差。当流场变化将堡礁（barrier reef，此处为CO₂源）的水体输送至研究站点时，岸礁区域观测到了CO₂向大气的净逸出。