Photosynthesis patterns in Chesapeake Bay phytoplankton: short- and long-term responses of P-l curve parameters to light

Abstract

Pigment concentrations and photosynthetic rates of phytoplankton in Chesapeake Bay were examined to determine short- and long-term responses to light. Samples were collected horizontally along a turbidity gradient and vertically relative to the depths of the pycnocline and photic zone. This approach provided phytoplankton assemblages that were exposed to light differing in both intensity and time-scale of change. Photosynthesis-irradiance (P-I) curves and the parameters alpha super(B) and P sub(m) super(B) were assayed at light intensities and wavelength bands that occur in situ. Findings have implications for the use of P-I curve parameters in diagnosing photoadaptive responses by phytoplankton and for the seasonal abundance of cyanobacteria possibly associated with eutrophication of Chesapeake Bay.