Adolf, J. E. University of Maryland Center for Environmental Science, Horn Point Lab, jadolf@hpl.umces.edu
MacIntyre, H. L. University of Maryland Center for Environmental Science, Horn Point Lab, macintyr@hpl.umces.edu

 
PHOTOSYNTHETIC AND BIO-OPTICAL PROPERTIES OF A PROROCENTRUM MINIMUM BLOOM: RELATIONSHIPS TO ENVIRONMENTAL VARIABILITY
 
A bloom of the dinoflagellate Prorocentrum minimum occurred in the Choptank River, a sub-estuary of Chesapeake Bay (MD, USA), during May 1998. Daily samples were taken to examine variability in photosynthetic and bio-optical properties of the assemblage in relation to environmental parameters. Biomass ranged from 50 to 750 micrograms Chl a / l over the 2-week sampling period and was positively correlated with k(PAR), resulting in low mean water-column irradiance. Maximum quantum yield and photosynthetic capacity showed approximately 3- and 5-fold variation, respectively, over the study period. Maximum quantum yield also varied inversely with the pool size of diatoxanthin measured in darkness. Variation in chlorophyll-specific photosynthetic parameters showed strong positive correlations with DIC and DIN:DIP, and a strong negative correlation with temperature and pH. High biomass coincided with significant drawdown of DIN, DIC and a reduction in photosynthetic parameters. Rapid changes in environmental conditions were apparently driven by the high biomass present during the bloom. The mechanisms by which dinoflagellate populations maintain growth in highly variable environmental conditions is key to understanding bloom dynamics.
 
Day: Friday, Feb. 5
Time: 04:00 - 04:15pm
Location: Eldorado Hotel
 
Code: SS42FR0400E