Did biological activity in the Ionian Sea change after the Eastern Mediterranean Transient? Results from the analysis of remote sensing observations

Abstract

The possible impact of the Eastern Mediterranean Transient (EMT) on the autotrophic biomass distribution has been investigated through a detailed analysis of remote sensing observations on a basin scale. Since the EMT effect was circumscribed in time, satellite data from Coastal Zone Color Scanner (CZCS) and Sea‐viewing Wide Field‐of‐view Sensor (SeaWiFS), relative to the pre‐ and post‐EMT period, respectively, were utilized for the study. The results of the analysis demonstrate that the changes in the circulation of the eastern Mediterranean Sea did not affect the general patterns of biomass distribution in the basin. The chlorophyll a fields at the surface were substantially similar in the CZCS and SeaWiFS periods, showing similar spatial patterns and only a slight difference in the timing of the main events. On the other hand, in the SeaWiFS period a recurrent and large patch of chlorophyll a was detectable in the northwestern Ionian Sea. The analysis of existing data supports the possibility that this new structure is the result of changes related to the EMT, though the observed subregional enhancement of biomass occurred only in an area where concurrent factors such as doming and convection played a synergistic role with the EMT‐induced changes.