³§±è±ð²¹°ì±ð°ù:ÌýEileen Hofmann, Â鶹´«Ã½
Meeting ID: 924 4609 2781
Passcode: 664304
Abstract
The recently funded NOAA MERHAB (Monitoring and Event Response for Harmful Algal Blooms) project has the goal of developing predictive capability for harmful algal blooms in Chesapeake Bay. As part of this effort, a vertically dependent model, implemented for the Lafayette River, a shallow, tidal sub-tributary of the lower Chesapeake Bay, is being used to assess the relative contributions of physical forcing and biological potential on initiating and maintaining blooms of the harmful algae, Margalefidinium polykrikoides. Simulations showed that vertical migration by M. polykrikoides supports autotrophic growth in the well-lit surface waters and provides access to organic matter reservoirs and regenerated nutrients near the bottom that support heterotrophic growth. The ability to access the biological potential of the lower water column with organic matter reserves is important in maintenance of cell growth that supports blooms into late summer when inorganic nitrogen is depleted. Simulated M. polykrikoides blooms are constrained by a thermal range that is conductive to algal cell growth. Short-term warming of 1ºC to 3ºC for 5 to 10 days imposed in early June and July shifted bloom initiation earlier, reduced bloom magnitude, and suppressed the late summer bloom. Imposition of warming in August has little effect on the bloom cycle. The timing and duration of short-term warming may underlie the year-to-year variability observed for M. polykrikoides in the Lafayette River.
Biography
Eileen Hofmann is an oceanographer who studies physical-biological interactions in marine ecosystems, the transmission of marine diseases, and marine food webs. She is a Professor and Eminent Scholar in the Department of Ocean and Earth Sciences and Center for Coastal Physical Oceanography at Â鶹´«Ã½. Her current research focuses on Chesapeake Bay ecology, the potential effects of offshore wind energy on shellfish fisheries, and eelgrass wasting disease.