Author: Robin  Fuchs,  PhD Student (Mediterranean Institute of Oceanography (MIO))

Designation: 

Description:
Pico-nanophytoplankton are dominant and main primary producers in the oligotrophic regions of the oceans. Their contribution to the oceanic component of the global carbon cycle is difficult to estimate because of the vast sampling domain, the small sizes of the cells, and their highly adaptive growth rates. Altogether, these limitations lead to large uncertainties in global primary production estimates. The bay of Marseille (NW Mediterranean Sea), which is considered almost oligotrophic, is influenced by intermittent wind events causing upwelling (northerlies) and downwelling (south-easterlies) events with substantial consequences on water temperature and dissolved nutrients. Using a CytoSense flow cytometer continuously operating at a two hours frequency since September 2019 at the Seawater Sensing Laboratory At MIO Marseille, we monitored the absolute abundances of six phytoplankton functional groups over a complete annual cycle. Several episodic upwelling and downwelling events were detected and analysed together with a set of atmospheric and oceanic variables. We show that despite their short durations, these events trigger important and differentiated responses at the community level both in terms of abundance and growth rate. Due to their frequent occurrences, they are likely to significantly contribute to primary production budgets in the region.

Category: Scientific Program Abstract > Special Sessions > SS44 Modelling the ecology & evolution of plankton