The Eastern Mediterranean Sea biogeochemical dynamics in the 1990s: A numerical study

Abstract

The coupled physical-biogeochemical dynamics of the Mediterranean Sea have been hindcasted for the decade 1990-2000 with the Nucleus for European Modeling of the Ocean-Biogeochemical Flux Model coupled modeling system. This work describes and discusses the simulated changes in the Eastern Mediterranean Sea physical and biogeochemical dynamics occurring in the 1990s, contemporary to the establishment of the Eastern Mediterranean Transient. The physical component of the modeling system reproduces several changes in the Eastern Mediterranean physical dynamics and thermohaline structure that are consistent with observations pertinent to the transient period. The simulated change in the atmospheric forcing during the early 1990s is considered sufficient to develop upwelling favorable conditions that determine an overall upward displacement of the simulated deep Eastern Mediterranean nutrient pool. Model results indicate that in the post transient period, the displaced nutrients were advected westward along with the reestablishment of the Levantine Intermediate Water pathway, and together with the occurrence of strong winter mixing events in the Ionian Sea, they determined an increase of the primary production processes in the euphotic layer along the eastern coast of Ionian Sea and northern Levantine basin. The biogeochemical model suggests that such an increase in productivity apparently impacted mostly the microbial branch of the marine trophic web. Key Points Changes in thermohaline characteristics of the Mediterranean affect ecosystem Changes in Mediterranean circulation strongly depend on winter forcing Physical changes impact mostly Mediterranean microbial food web ©2013. American Geophysical Union. All Rights Reserved.