Ocean Acidification Time-Series and Projections for the Gulf of Maine

Chair: Samantha Siedlecki

Dwight K. Gledhill(1), Joe Salisbury(2), Chris Hunt(2), Sylvia Musielewicz(3), Doug Vandemark(2)

1 NOAA Ocean Acidification Program, Silver Spring, MD, 20910 USA
2 UNH Earth Oceans & Space, Durham, NH, 03824-3525, USA
3 NOAA Pacific Marine Environmental Laboratory, Seattle, WA, 98115, USA

Background
The Gulf of Maine (GOM) is a continental shelf sea bounded by Cape Cod, USA and Nova Scotia, CA. Separated from the open Atlantic by Georges and Browns banks, the waters of the GOM experiences considerable fresh water input from coastal sources from along the Scotian Shelf and coastal Maine. As a result, the GOM is considerably less buffered against ocean acidification relative to offshore Atlantic waters at comparable latitude. The GOM supports significant shellfish-based industries dependent on biocalcification processes throughout the region with American lobster and sea scallop comprising approximately two-thirds of the $1.2 billion in commercial landings revenue. The enhanced sensitivity to ocean acidification combined with significant economic dependence on impacted species makes the Gulf of Maine a potential hot-spot region for continued ocean acidification.

Methods
For the past decade, scientist from UNH and NOAA have been monitoring changes in Gulf of Maine carbonate chemistry at the Coastal Western Gulf of Maine Ocean Acidification Mooring (43.02oN,70.54oW) using autonomous sensors and repeated ship surveys.

Findings
Here we examine the time-series data in the context of ocean acidification specifically with regards to potential critical thresholds as established in the literature for bivalve larvae.

Conclusions
We will assess inter-annual variability in the extent and duration of potentially harmful periods based on these thresholds and make estimates of pre-industrial conditions and future projections under two IPCC scenarios. We will discuss the key assumptions and explore how changes in temperature, salinity, and primary productivity could alter the prognosis for the GOM.