Spatial and temporal variation of photosynthetic parameters of phytoplankton in a subtropical coastal lagoon

Abstract

We generated photosynthesis–irradiance ( P– E) and phytoplankton absorption data for a coastal lagoon of northwestern Baja California. This was done for different seasons and tidal conditions. Using the vertical attenuation coefficient of light we partitioned the lagoon into two regions to run the 14C incubation experiments: an outer and an inner region. Since there is substantial variability within data sets, we conclude that it is not possible at this time to predict fine time-and-space scale variations in photosynthetic parameters. For simple primary production models, we recommend working averages for each of the two regions. There were no significant differences of the photosynthetic parameters average values for the same region and for different tidal conditions or seasons. The mean and standard error for the assimilation number were 14.6 and 2.6 mg C mg Chl −1 h −1, for the outer region, and 7.7 and 1.8 for the inner region, respectively. The mean and standard error for the initial slope were 0.036 and 0.008 mg C mg Chl −1 h −1 (μmol quanta m −2 s −1) −1, for the outer region, and 0.019 and 0.005 for the inner region, respectively. Average values of maximum photosynthetic quantum yield were 0.082 and 0.053 mol C (mol quanta) −1, for the outer and inner regions, respectively. Its standard error was the same for both regions (0.012). These average values should be used only for non-El Niño years.