SS3.02 Turbulence and Plankton Dynamics
Date: Wednesday, June 12, 2002
Location: Poster Session - VCC
 
FurusatoE, Environmental Hydraulic Institute Ltd., Saitama, Japan, furusato@ehi-jp.com
Asaeda, T, , Department of Environmental Science and Human Engineering, Saitama University, Saitama, Japan, asaeda@post.saitama-u.ac.jp
 
THE RELATION BETWEEN THE TYPE OF ANTENNA PIGMENTS OF DOMINANT CYANOBACTERIA AND THE AMBIENT STRATIFICATION CONDITION IN RESERVOIRS
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Antenna pigments types, phycocyanin or phycoerythrin, of dominant cyanobacteria was investigated periodically in two Japanese reservoirs in relation to thermal stratification profiles. Phycocyanin type was dominant in a strong stratification with small mixing depth, while in a weak stratification with deep mixing depth phycoerythrin type was dominant, which was clearly classified by the Wedderburn number with O(1) as the boundary. The theoretical analysis was conducted with characteristics of light harvesting of these pigments and the underwater light extinction coefficient, and the mixing depth. In a stable stratification with shallower mixing depth and lower transparency relatively high intensity of red component allows the dominance of phycocyanin type, while in an unstable condition with deeper mixing depth and higher transparency phycoerythrin type becomes dominant due to the green components of light. Verification of this analysis with observed data in reservoirs provides the condition that larger than about 0.0001 of the average buoyancy frequency is the minimum requirement for the dominance of phycocyanin type cyanobacteria.