Oceanographic Response to Climate in the Northwest Atlantic

MERCINA (Marine Ecosystem Responses to Climate In the North Atlantic) Working Group

Andrew J. Pershing, Charles H. Greene
Cornell University
Ithaca, New York, USA

Charles Hannah, Doug Sameota, Erica Head
Bedford Institute of Oceanography
Dartmouth, Nova Scotia, Canada

David G. Mountain
National Marine Fisheries Service
Woods Hole, Massachusetts, USA

Jack W. Jossi
National Marine Fisheries Service
Narragansett, Rhode Island, USA

Mark C. Benfield
Louisiana State University
Baton Rouge, Louisiana, USA

Philic C. Reid
Sir Alister Hardy Foundation for Ocean Science
Plymouth, United Kingdom

Ted G. Durbin
University of Rhode Island
Narragansett, Rhode Island, USA


Situated in an oceanographic transition zone, the Gulf of Maine/Western Scotian Shelf (GOM/WSS) region of the Northwest Atlantic is especially susceptible to changes in the climate system. Recent studies have shown that a coupled slope water system (CSWS) operates in the Northwest Atlantic and responds in a similar manner to climatic forcing over a broad range of time scales. These studies further suggest that it may be possible to associate different modes of the CSWS with different phases of the North Atlantic Oscillation (NAO). Results from recent GLOBEC field studies in the Northwest Atlantic provide strong evidence linking physical responses of the CSWS to basin-scale forcing associated with the NAO. By placing these results in the context of time-series datas collected from the GOM/WSS region over the past half century, we show that: (i) the region's shelf ecosystems respond both physically and biologically to modal shifts in the CSWS; (ii) the CSWS mediates the effects on these ecosystems of basin-scale climatic forcing associated with the NAO; and (iii) certain planktonic species can be good indicators of the CSWS's modal state on interannual to inderdecadal time scales.