VIMS students recognized at national conference

Six graduate students from the Virginia Institute of Marine Science took home awards for their presentations during the Estuarine Research Federation's Annual Meeting in Norfolk, Virginia in October.

The Estuarine Research Federation (ERF) is the nation's leading scientific society devoted to the study and management of estuaries and the effects of human activities on these fragile environments. The 1,200-member federation includes a unique mix of academic researchers, public-sector managers, teachers, consultants, and students.

Graduate student Malcolm Scully received third place in the graduate student competition for his talk on turbulent mixing in estuaries. Jessie Campbell won an honorable mention for her talk on the ecological factors affecting the germination of sea-grass seeds. David Gillett, Grace Henderson, Frank Parker, and Adriana Veloza were recognized as among the top 50 student presenters.

Scully, a Ph.D. student under faculty advisor Dr. Carl Friedrichs, won the $300 third-place prize for his study of how differences in water density affect residual flow in the York River and other similar estuary systems. Residual flow refers to the average motion of water and suspended particles in a tidal system over multiple tidal cycles. Accepted wisdom holds that particles in the surface layer of less-dense fresh water gradually move downstream over many cycles of flood and ebb tide, whereas particles in the saltier, denser bottom layer move upstream. Scully's work shows that in estuaries where deep channels are flanked by shallow shoals, the lateral distribution of the residual flow is sometimes opposite from the expected pattern because of turbulent mixing. The ability to understand and model residual currents has important implications for predicting the transport of contaminants, sediments, and larvae in the Bay and other estuarine systems.

Campbell, a Master's student under faculty advisor Dr. Ken Moore, received honorable mention for her study of seed germination in a type of sea grass called wild celery (Vallisneria americana). Although this and other sea grass species are known to produce large numbers of seeds, researchers don't know for certain how important these seeds are to the plants' dispersal (the plants can also spread by sending out runners). Campbell's experiments showed that wild celery seeds germinate most successfully when oxygen is present, water temperatures exceed 70°, the water is only slightly salty, and seeds are buried less than one-half inch deep. Her results can be used to help improve sea grass restoration efforts in Chesapeake Bay and elsewhere.

Gillett, a Ph.D. student under faculty advisor Dr. Linda Schaffner, was recognized for his study of the relationship between the health of bottom habitats and their ability to support fish and other animals higher up the food chain. He found that undisturbed communities of bottom-dwelling organisms are able to support much healthier ecosystems than similar communities that have been disturbed by human activities such as excessive nutrient input. His quantification of this relationship will allow resource managers to better monitor and predict the effects of human disturbance on marine communities.

Henderson, a Ph.D. student under faculty advisor Dr. Deborah Steinberg, was acknowledged for her efforts to better understand how feeding by zooplankton affects carbon and nutrient cycling in estuarine and marine systems. Her experiments show that the smallest zooplankton release carbon and nitrogen in forms that are readily recycled by phytoplankton and bacteria. Incorporated into models, her results can help predict how human impacts such as nutrient pollution or global climate change will affect marine ecosystems.

Parker, a Ph.D. student under faculty advisor Dr. Iris Anderson, was recognized for his presentation on how carbon and nutrient cycling is affected by the microscopic plant community that lives atop sunlit sediments. His research suggests that these plants recycle carbon and nitrogen in different ways, which has important implications for understanding how carbon and nitrogen are transferred among plants, bacteria, and invertebrates in estuaries.

Veloza, a Master's student under faculty advisors Drs. Fu-Lin Chu and Kam Tang, was recognized for her presentation on "trophic upgrading." This is the process by which certain single-celled marine animals increase their nutritional value to predators by transforming substances within their own prey into fatty acids that organisms higher up the food chain need to thrive. Her results have important implications for understanding fluctuations in fish populations in Chesapeake Bay and elsewhere around the world, as nutrient limitation of zooplankton production is one of the key factors regulating the "recruitment" of juvenile fish into the adult population.

Campbell and the winners of the "Top 50" awards each received a copy of Ivan Valiela's new book, Doing Science: Design, Analysis, and Communication of Scientific Research. Dr. Valiela, recipient of the Estuarine Research Federation's William A. Niering Award, donated his honorarium to this cause.