TITLE:      Phytoplankton production off Marguerite Bay, Western Antarctic
            Peninsula, Winter 2001 
	    Third U.S. Southern Ocean Globec Science Investigator Meeting
AUTHORS:    Maria Vernet
DATE:       10-12 December 2001
PLACE:      Arlington, VA
Posted WEB: http://www.ccpo.odu.edu/Research/globec/3sciinvest/vernet.htm

ABSTRACT

Phytoplankton in high-latitude areas experience a strong seasonal cycle as a
consequence of changes in day length. During the fall and winter of 2001, as 
part of two GLOBEC cruises, we measured phytoplankton daily primary production 
with simulated in situ experiments. Primary production from 0 to 30 m was very
low and decreased from an average 14.76 plus/minus 33.11 mg C m2/d in May 
to 2.54 plus/minus 2.62 mg C m2/d in August. The decrease in phytoplankton
biomass caused the lowering of primary production, despite a twofold increase 
in incident radiation between May and August. Chlorophyll a concentration was
low in the fall and decreased further by two orders of magnitude later in the
season.  For example, integrated chlorophyll from 0 to 30 m decreased from
9.02 plus/minus 11.0 mg/m2 to 0.60 plus/minus 0.21 mg/m2, respectively.
Spatially, there was a coherent pattern of primary production distribution 
between the seasons, with higher activity on the shelf off Adelaide Island. 
These results suggest that primary production in the water column is limited 
by phytoplankton biomass and that these conditions will remain until 
phytoplankton populations start to grow as ice recedes later in the season.