Identifying the dominant process (physical versus biological) in pelagic marine ecosystems from field estimates of chlorophyll a and phytoplankton production

A new approach is described to identify the dominant process (physical versus biological) in a pelagic marine ecosystem, from simple biological oceanographic field variables. The approach is based on quantification of the matching (M) between phytoplankton production (P) and losses, from field estimates of chlorophyll a(Chl) and P. Coefficient M is estimated for a wide range of oceanic and coastal environments and of trophic characteristics, using dat from the literature. Results show that M characterizes the dominance of physical versus biological processes in pelagic systems. The coefficient may be especially useful as a means for extracting process information on pelagic marine ecosystems from large data sets of Chl and P, e.g. recorded by moored instruments or provided by satellite images of ocean colour.