Harding, Jr., L. W.. University of Maryland, larry@kestrel.umd.edu
Hood, R. W.. University of Maryland, raleigh@hpl.umces.edu
Scardi, M. Statione Zoologica, mscardi@mclink.it

 
ENHANCED PHYTOPLANKTON BIOMASS AND PRODUCTIVITY ASSOCIATED WITH PERSISTENT MESOSCALE EDDIES IN THE LOWER CHESAPEAKE BAY
 
Phytoplankton biomass and productivity in Chesapeake Bay are largely regulated by nitrogen (N) loading on an annual basis. In years of average freshwater flow, phytoplankton in the lower Bay are strongly N-limited in summer and the annual productivity peak is supported by regenerated N and advective inputs. Chlorophyll concentrations seaward of the Potomac R. mouth are generally low after May, with the exception of several specific regions where physical circulation promotes retention. For one such region, persistent mesoscale eddies were recently identified using a 2-dimensional Lagrangian particle trajectory model. This convergent feature is accompanied by accumulations of gelatinous and crustacean zooplankton and fish larvae. Our data from shipboard and aircraft surveys show this region is consistently enhanced in phytoplankton biomass and in this paper we quantify enhanced biomass and productivity in these eddies. Data sources are in-situ data from the LMER Trophic Interactions in Estuarine Systems (TIES) program and ocean color observations from the Ocean Data Acquisition System (ODAS) and SeaWiFS Aircraft Simulator (SAS III). We suggest accumulation of metazoan grazers, enhanced carnivory by gelatinous zooplankton, and advective N inputs in nearby divergences combine to yield high phytoplankton biomass and productivity in an otherwise N-deplete region of the Bay generally characterized by low chlorophyll concentrations and primary productivity.
 
Day: Thursday, Feb. 4
Time: 09:00 - 09:15am
Location: Hilton of Santa Fe
 
Code: SS04TH0900H