PHYTOPLANKTON PATCHINESS - QUANTIFYING THE BIOLOGICAL CONTRIBUTION USING FAST REPETITION RATE FLUOROMETRY

The coupling between physical and biological processes is important in the marine environment because phytoplankton growth and turbulent mix ing operate on similar time scales. Since the 1970s, the relative cont ribution of these two parameters to phytoplankton patchiness has been studied using analytical tools such as spectral analysis. Here, for th e first time, we combine spectral analysis with Fast Repetition Rate F luorometry as a method of quantifying the importance of photosynthetic efficiency in the biological-physical interactions that lead to ocean ic chlorophyll distributions. The results indicate that photosynthetic efficiency is correlated with the sum of the corresponding chlorophyl l power spectrum; a measure of the total spatial variability of chloro phyll. In addition, high photosynthetic rates are associated with regi ons where the spatial distributions of chlorophyll and salinity differ , as quantified by the slopes of their respective power spectra. The r esults are particularly evident at large spatial scales, representing an empirical verification of previous theoretical work regarding phyto plankton spatial structure.