Influence of Rossby waves on primary production from a coupled physical-biogeochemical model in the North Atlantic Ocean

How do Rossby waves influence primary production in the North Atlantic Ocean? Rossby waves have a clear signature on surface chlorophyll concentrations which can be explained by a combination of vertical and horizontal mechanisms (reviewed in Killworth et al., 2004). In this study, we aim to investigate the role of the different physical processes to explain the surface chlorophyll signatures and the consequences on primary production using a 3-D coupled physical/biogeochemical model for the year 1998. The analysis at 20 given latitudes, mainly located in the subtropical gyre, where Rossby waves are strongly correlated with a surface chlorophyll signature, shows that vertical and horizontal processes are involved in the surface chlorophyll anomalies. Furthermore, the ecosystem response is, as expected, stronger when vertical input of dissolved inorganic nitrogen is observed. The surface chlorophyll anomalies, induced by these physical mechanisms, have an impact on primary production. We then estimate that Rossby waves induce, locally in space and time, increases (generally associated with the wave crest) and decreases (generally associated with the wave trough) in primary production (±20% of the estimated primary production). This symmetrical situation suggests a net weak effect of Rossby waves on primary production