The NEFSC Office of Marine Ecosystem Studies (OMES) has launched its new website, featuring the first advisory on ecosystem conditions across the Northeast Continental Shelf Large Marine Ecosystem. The Office intends to update the advisory twice yearly, providing a handy reference on trends in primary productivity, zooplankton biomass and diversity, and sea surface temperatures on the shelf.

“All over the world, researchers are parlaying what’s known about individual components of the ocean’s systems into projects to figure out how the system as a whole works,” said Dr. Ken Sherman, OMES Office director.

A diverse group of zooplankton: top left - copepod; top center -  fish larva; lower right - copepods and fish larvae. Photo by NMFS/NEFSC Plankton Demography Program.

Sherman knows what he is talking about. He is a leading figure in the international effort to define large marine ecosystems (LMEs) throughout the world’s oceans and develop ways for neighboring countries to collectively study and govern their use. Last year, he was awarded a Department of Commerce gold medal for his work to develop this international network, and for his pioneering efforts in marine ecosystems research.

Sherman and his group intend to understand not only individual stock dynamics but also how, and how well, the ecosystem is functioning. To do that, standardized i ndicators of changing ecosystem conditions need to be developed and become widely accepted. “A common language, or system of measuring and understanding change is critical to any attempt to manage an LME successfully,” said Sherman. Development and testing of these indicators are important areas of study for OMES.

“That’s what we are doing here at Narragansett for the Northeast continental shelf ecosystem. This advisory is one example, comparing in a fairly simple way three important ocean components: zooplankton and chlorophyll abundance, and sea surface temperature,” said Sherman. “We’ve certainly got a head start over many other places in the world simply because we have a wealth of data,” said Sherman, “The data in the advisory report, for example, are collected from satellite imagery and in the field over decades,” Sherman explains.

Jay O’Reilly, long-time researcher at Narragansett, analyzes oceanographic data captured by remote sensing. “Our sea surface temperature data from NOAA satellites extends from 1985 to the present and allows us to compare current trends in temperature with historical conditions,” said O’Reilly. “By using ocean color data from sensors on U.S. satellites, we can closely monitor changes in the production of phytoplankton, a key ingredient in the health and productivity of the shelf ecosystem.”

“What we can immediately see by comparing these three large data sets,” said Sherman, “is a trend of relatively stable temperatures and chlorophyll, as well as an increase in zooplankton.”

How can that tell us more about how the ecosytem works? Well, one think people are very interested in is what factors influence primary productivity—the conversion of sunlight into plankton.

“Plankton are an important source of energy for the food web,” says Dr. Jon Hare. Hare is part of the Oceanography Branch of the NEFSC’s Environmental Processes Division, specializing in plankton and ecosystem monitoring, and works closely with OMES.

“Plankton is important in two ways,” said Hare. “The first is that much of the energy in marine ecosystems moves through the planktonic part of the food chain before entering fish, crabs, lobsters, and other higher levels. The second is that most fish and invertebrates have planktonic early life stages. The abundance of most of these populations as adults is highly dependent on good survivorship during the planktonic life stages.”

Hare recently came aboard at the NEFSC, from the NOAA Laboratory in Beaufort, N.C. One thing that lured Hare north was the unique and extensive data sets available for different parts of the Northeast Shelf ecosystem, including that for plankton. “These data sets are well maintained and still growing,” notes Hare. “Here at Narragansett we are working toward understanding linkages between the environment and phytoplankton, zooplankton, and fish abundance. We’re not to the point where those linkages are quantitative or predictive, but that’s where our research is leading.”

If changes in factors like primary production and sea surface temperatures can be tied to how successfully fish reproduce in a given year, that would be a major improvement in the tools for managing ocean use.

Dr. Kevin Friedland works on that end of the spectrum, as part of the OMES effort in fishery oceanography studies. “We are now at the point with these datasets where we can begin to make meaningful time series comparisons,” said Friedland. “Zooplankton is increasing. Although the increase is not uniform over seasons or areas, overall it’s up, which suggests it is not a limiting factor for fish that rely on zooplankton prey. With additional study, we may well link this factor, or others, to fish reproductive success and population declines and recoveries.”

Posted June 13, 2006