Short‐term and seasonal pH, p CO 2 and saturation state variability in a coral‐reef ecosystem

摘要: [1] Coral reefs are predicted to be one of the ecosystems most sensitive ocean acidification. To improve predictions coral reef response acidification, we need better characterize natural range variability pH, partial pressure carbon dioxide (pCO2) and calcium carbonate saturation states (Ω). In this study, autonomous sensors for pH pCO2 were deployed on Media Luna reef, Puerto Rico over three seasons from 2007 2008. High temporal resolution CaCO3 calculated in situ data, giving a much more detailed characterization than previously possible. Reef aragonite (ΩAr) ranged 7.89 8.17 units, 176–613 μatm 2.7–4.7, respectively, characteristic other studied ecosystems. The diel Ω cycles also large, encompassing about half seasonal variability. Warming explained 50% supersaturation mean pCO2, with remaining primarily due net heterotrophy production. Net was likely driven by remineralization mangrove derived organic which continued into fall, sustaining high levels until early winter when returned offshore values. As consequence, source CO2 atmosphere during summer fall sink winter, resulting annual 0.73 ± 1.7 mol m−2 year−1. These results show that exposed wide their environment. Mean ΩAr will drop 3.0 atmospheric increases 500 less greater 70% time summer. Long duration exposure these low expected significantly decrease calcification rates reef.