Acidification, hypoxia, and algal blooms: Barriers to current and future ecosystem restoration and climate change resilience in Jamaica Bay

Gobler, Christopher; Wallace, Ryan

Jamaica Bay (New York, USA) is a eutrophic ecosystem located along the southwest corner of Long Island, NY, USA. While management plans for the bay include bivalve restoration, prior observations suggest that the occurrence of hypoxia and acidification within Jamaica Bay could be inhibitory to these populations. This project was established to provide high temporal and spatial scale resolution of hypoxia, acidification, and algal blooms in Jamaica Bay and to assess the extent to which these occurrences may influence the growth of bivalves that may be the targets of future restoration efforts. From 2014 through 2016, a series of novel approaches were used to assess water quality trends in Jamaica Bay including continuous, horizontally profiling water quality sondes, vertically profiling water quality sondes in fixed locations and aboard moving vessels, and fixed location sondes deployed for extended periods. Bivalve growth experiments were performed in tandem with the deployment of continuous water quality sondes. The intensity of hypoxia and acidification within Jamaica Bay varied spatially, diurnally, and seasonally and was strongly influenced phytoplankton blooms. Bottom waters transitioned from being well-oxygenated and having normal carbon dioxide (CO2) concentrations in spring to hypoxic, anoxic, and acidified through summer. Diurnal shifts in acidification and hypoxia were most intense in late summer within regions with poor flushing, excessive nutrient loads, and rapid respiration rates. Phytoplankton blooms promoted super-saturation of dissolved oxygen and increased alkalinity (basification) in surface waters, although within deeper regions these conditions sometimes overlaid waters that were hypoxic and acidified. Bivalves including eastern oysters (Crassostrea virginica), bay scallops (Argopecten irradians), and blue mussels (Mytilus edulis) grew at rapid rates across much of the bay during early and mid-summer. However, during experiments performed in late summer within regions with intense hypoxia and acidification, growth rates of eastern oysters and bay scallops were significantly slower than parallel cohorts grown regions of Jamaica Bay that were well-oxygenated and had normal CO2 concentrations despite near-equal levels of temperature, salinity, and algae. Collectively, this study demonstrates that hypoxia and acidification is an annual, seasonal occurrence within Jamaica Bay that varies diurnally, horizontally, and vertically and is strongly influenced by algal blooms. Intense hypoxia and acidification within certain areas of Jamaica Bay are likely detrimental to the establishment of bivalve populations in those regions.

Acidification, hypoxia, and algal blooms: Barriers to current and future ecosystem restoration and climate change resilience in Jamaica Bay

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