The metabolism rates are shown to be robustly modeled using a mass balance approach in two coastal reef systems at two fixed assets that could be employed elsewhere to monitor OA and its impacts within coral reef ecosystems. The data can be applicable to other sites with the similar auxiliary data and can be used in combination with other approaches, such as the turbulent flux, to estimate long-term metabolic rates in the field. Both sites were net heterotrophic and net dissolutional from late summer to fall, with occasional periods of net calcification and net autotrophy from winter to early summer. High respiration rates at CR and LP observed in the fall generated a local source of DIC to the system, causing a decrease in carbonate saturation states. During this time of the year, these processes may affect the reef’s susceptibility to other climate pressures and decrease the ability of upstream communities (e.g., seagrasses at CR) to serve as OA refugia. Surface waters at LP are likely to be affected by OA sooner and more strongly than surface oceanic waters due to the significant annual changes respiration and calcification have in coastal carbonate saturation states. Our results suggest that tropical Caribbean reef ecosystems are exhibiting long periods of net dissolution of highly soluble carbonate minerals based on similarities in environmental characteristics. Future research efforts should be directed to improve our understanding of the drivers of both calcification and organic production, at long-term and ecosystem scales.
Melendez M., 2020. Effects of nearshore processes on carbonate chemistry dynamics and ocean acidification. PhD thesis, University of New Hampshire, 146 p. Dissertation.