Trans-Atlantic Studies of Shelf Ecosystem Responses to Climate Variability and Change

Initial Plans

Organizers: Charles Greene, Charles Hannah

     	June 7, 2000,    ASLO Meeting
	  June 9, 2000,	 Copenhagen, Denmark
	  June 10, 2000

	January 2001	 National Center for Ecological Analysis & Synthesis	
			 Santa Barbara, CA	

We will form a Trans-Atlantic working group charged with studying the responses of North Atlantic shelf ecosystems to basin-scale forcings associated with different temporal modes of climate variability. The working group will adopt a regional to basin-scale perspective in examining the coupling of physical and biological processes. Specifically, we will focus on basin-scale climatic events, like the North Atlantic Oscillation (NAO), to compare how coupled physical and biological processes respond in regional networks of large marine ecosystems (LME's) found on both sides of the North Atlantic.

We plan to synthesize existing time-series data to examine how plankton community composition and primary production have responded to different temporal modes of climate variability. A retrospective comparison of physical oceanographic, phytoplankton, and zooplankton time series data collected from the NE and NW Atlantic will be conducted. The plankton data are derived from continuous plankton recorder (CPR) and net samples collected over the past fifty years; they are archived at the Bedford Institute of Oceanography, Northeast Fisheries Science Center, Sir Alister Hardy Foundation for Ocean Science, and Woods Hole Oceanographic Institution.

CPR zooplankton time-series data from the NE Atlantic have been analyzed extensively, and strong correlations between the NAO and zooplankton abundance have been identified. We propose to extend these analyses to the NW Atlantic to look for comparable correlations between the NAO and zooplankton abundance in the Gulf of Maine, on Georges Bank, and in the Middle Atlantic Bight.

In addition, we will examine the CPR color index data, collected over the whole North Atlantic Basin, and make comparisons of these data with ocean color satellite data from the Coastal Zone Color Scanner (CZCS) and Sea-viewing WIde Field-of-view Sensor (SeaWIFS). Although qualitative, the CPR color index data have been shown to provide reasonable estimates of phytoplankton biomass throughout the North Atlantic. If we can develop a strong relationship between the CPR color index data and the satellite ocean color data, then we will be in a better position to retrospectively examine the responses of North Atlantic primary production to the NAO over the past half century.

We will follow up these retrospective data analyses with modeling studies focusing on the response of the coastal Labrador Current system to the NAO. The coastal Labrador Current system extends over 5,000 km from the Labrador Sea to the Mid-Atlantic Bight. The physically and biologically interacting LME's in the southern portion of this coastal current system include Georges Bank, the Gulf of Maine, the Scotian Shelf, and the adjacent Slope Water. These LME's have been the focus of the US and Canadian Global Ocean Ecosystem Dynamics (GLOBEC) NW Atlantic Programs. We will use results from these recent GLOBEC field studies in an effort to quantify the intensity and NAO-driven variability of the interactions among these LME's. We propose to accomplish this by conducting simulation experiments using a regional-scale, coupled physical-biological model developed by the GLOBEC NW Atlantic Modeling Group.