URI Graduate School of Oceanography biological oceanographers Barbara K. Sullivan and Dian J. Gifford have been awarded $655,000 by the National Science Foundation to study the cause of substantial increases in the concentrations of the ctenophore Mnemiopsis leidyi (commonly called the combjelly) and determine the effects these increases could have on coastal ecosystems. An additional $244,000 was awarded to Dr. John Costello of Providence College to collaborate on the study.
At the location of the study in Narragansett Bay, Rhode Island, the increases in Mnemiopsis have been accompanied by seasonal shifts in their appearance from late summer to early spring during years with earlier warming of bay water temperatures. Because this timing coincides with the peak period of fish spawning in the region, the consequences of increased populations of a gelatinous predator such as Mnemiopsis could be quite significant.
Mnemiopsis leidyi is the same organism that has traveled from its usual home in northeastern U.S. waters in ballast water to invade and severely disrupt commercial fisheries in the Black Sea and the Sea of Azov.
Previous research indicates that this ctenophore is capable of clearing 100% of the fish eggs present in the upper reaches of the Bay when the outbreak of this jellyfish is at its maximum.
Combined with the recent documented decline of fish eggs and larvae over the last several years, the presence of this predator at critical spawning times could have far-reaching effects on the local commercial fishing industry. In addition, ctenophores may also be altering patterns of copepod abundance in spring, thereby changing the structure of the planktonic food web and depriving other marine organisms, including larval fish, of food.
“It’s exciting to be involved in this highly collaborative project,” said Gifford. “The Mnemiopsis population in Narragansett Bay, where the jellyfish has few natural predators, provides an unusual opportunity to study the biological dynamics of a zooplankton population in the context of climate change.”
Sullivan and Gifford have designed a research program that will sample the variables relevant to the initiation and maintenance of ctenophore outbreaks, including reproduction and growth of Mnemiopsis leidyi, the prey environment and the physical environment of Narragansett Bay. The three-year study will begin in October.
GSO graduate students Lindsay Sullivan, Angie Allen, and Hao-Hsien Chang will assist Sullivan and Gifford in this study. A resident of Kingston, Barbara K. Sullivan is a senior marine research scientist, an adjunct professor of oceanography, and professor in residence. She received a B.A. in biology from Catholic University, an M.S. in water resources management from John Hopkins University, and a Ph.D. in biological oceanography from Oregon State University.
Dian J. Gifford is an associate marine research scientist, an adjunct professor of oceanography, and a professor in residence. She received a B.A. in biology from the University of Massachusetts, and an M.S. in biology and a Ph.D. in oceanography from Dalhousie University, Halifax, Nova Scotia. She lives in Westport, Massachusetts.
The URI Graduate School of Oceanography is one of the country's largest marine science education programs, and one of the world's foremost marine research institutions. Founded in 1961 in Narragansett, RI, GSO serves a community of scientists who are researching the causes of and solutions to such problems as acid rain, global warming, air and water pollution, oil spills, overfishing, and coastal erosion. GSO is home to the Coastal Institute, the Coastal Resources Center, Rhode Island Sea Grant, the Ocean Technology Center, and the National Sea Grant Library.