Seawater carbonate chemistry and characterization of oyster growth and calcification on constructed oyster reefs

This study, therefore, sought to (1) characterize the baseline pH/DO variability as well as the associated drivers of the carbonate system in constructed reefs to (2) determine the reefs' influence on the biogeochemistry of the overlying waters and (3) evaluate the impacts, if any, on resident oysters, particularly in environments already prone to coastal acidification. To do this, we conducted a 4-year study (2018–2021) of multiple constructed subtidal oyster reefs in Shinnecock Bay, NY USA. We monitored the growth of three oyster reefs over four consecutive years and established high frequency time series of pHNBS, DO, and other relevant environmental parameters in both regional ambient seawater and reef-modified seawater during the summer months (when coastal acidification is most prevalent and oyster growth is maximal) over two of the four years. During one year, these data were paired with weekly surveys characterizing habitat macroalgae abundance and with biweekly sampling of reef and control seawater for discrete measurements of DIC, TA, and chlorophyll a. Finally, two in situ oyster experiments were conducted during the summers of two separate years to evaluate the impact of reef-modified seawater conditions versus ambient seawater conditions on juvenile oyster growth and survival.