Center for Coastal Physical Oceanography & ODU Resilience Collaborative



Fall 2017 Seminar Series

"INITIATION OF COCHLODINIUM POLYKRIKOIDES BLOOMS IN THE LOWER CHESAPEAKE BAY:
HOT SPOTS AND HOT TIMES"


Margie Mulholland
Department of Ocean, Earth & Atmospheric Sciences, Old Dominion University

Monday, October 23, 2017
3:30 PM
Conference Center, Innovation Resarch Building II
4211 Monarch Way, Norfolk, VA 23508

Abstract

Massive, months-long blooms of the dinoflagellate, Cochlodinium polykrikoides, have occurred throughout lower Chesapeake Bay and its tributaries in most of the last 20+ years. Based on long-term, high-frequency monitoring, we have identified hotspots for bloom initiation in the Lafayette and Elizabeth Rivers, sub-tributaries of the lower Chesapeake Bay. There are interannual differences in the timing, magnitude and duration of blooms and these appear to be related to interannual differences in the timing of increases in water temperature and physical processes that dominate tidal estuaries. While specific ranges of temperature and salinity properties appear to be necessary, they are not sufficient for bloom development. Because C. polykrikoides make cysts residing in the sediments, sediment resuspension is an important precursor to bloom formation. Little is known about the life cycle of C. polykrikoides and the environmental factors necessary for successful excystment. Bloom initiation has been linked locally with sediment and nutrient resuspension, stratification, and estuarine circulation as modulated by spring-neap tidal cycles and meteorological pertubations. Once initiated, mixotrophic C. polykrikoides populations can meet their nutritional needs in a variety of ways. Vertical migration may facilitate their acquisition of nutrients and may allow them to avoid predation.


Biography

Dr. Mulholland received a B.S. in Geology and Biology from the University of Notre Dame. She earned a M.S. in Biological Oceanography and a M.M.A. in Marine Affairs (Policy), both from the University of Washington. Her Ph.D. in Oceanography came from the University of Maryland's Chesapeake Biological Laboratory. Dr. Mulholland has had visiting appointments in the Philippines and Japan, served as a Peace Corps volunteer, and was a postdoc and research assistant professor at the State University of New York, Stony Brook. Presently, she is a professor in the Department of Ocean, Earth and Atmospheric Sciences at Old Dominion University.


Reception before seminar at 3:00 PM


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