Comparison of CO2 dynamics and air-sea exchange in differing tropical reef environments

• Published in: Aquatic Geochemistry
• Main Authors: Drupp, Patrick S., De Carlo, Eric H., Mackenzie, Fred T., Sabine, Christopher L., Feely, Richard A., Shamberger, Kathryn E. F.
• Format: Report
• Language: English
• Published: 2013
• Subjects: Carbon dioxide; Alkalinity; Gas exchange; Coral reefs; Tropical; Pacific; High Island; Carbonic acid
• Online Access: https://hdl.handle.net/1912/6503

Author Posting. © The Author(s), 2013. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Aquatic Geochemistry 19 (2013): 371-397, doi:10.1007/s10498-013-9214-7. Note from corresponding author: authors Feely and Shamberger were added after the initial submission, but before the final submission. An array of MAPCO2 buoys, CRIMP-2, Ala Wai, and Kilo Nalu, deployed in the coastal waters of Hawaii have produced multiyear high temporal resolution CO2 records in three different coral reef environments off the island of Oahu, Hawaii. This study, which includes data from June 2008-December 2011, is part of an integrated effort to understand the factors that influence the dynamics of CO2-carbonic acid system parameters in waters surrounding Pacific high island coral reef ecosystems and subject to differing natural and anthropogenic stresses. The MAPCO2 buoys are located on the Kaneohe Bay backreef, and fringing reef sites on the south shore of O’ahu, Hawai’i. The buoys measure CO2 and O2 in seawater and in the atmosphere at 3-hour intervals, as well as other physical and biogeochemical parameters (CTD, chlorophyll-a, turbidity). The buoy records, combined with data from synoptic spatial sampling, have allowed us to examine the interplay between biological cycles of productivity/respiration and calcification/dissolution and biogeochemical and physical forcings on hourly to inter-annual time scales. Air-sea CO2 gas exchange was also calculated to determine if the locations were sources or sinks of CO2 over seasonal, annual, and interannual time periods. Net annualized fluxes for CRIMP-2, Ala Wai, and Kilo Nalu over the entire study period were 1.15 mol C m-2 yr-1, 0.045 mol C m-2 yr-1, and -0.0056 mol C m-2 yr-1, respectively, where positive values indicate a source or a CO2 flux from the water to the atmosphere, and negative values indicate a sink or flux of CO2 from the atmosphere into the water. These ...