Coastal-offshore exchange of organic matter across the Cape Ghir filament (NW Africa) during moderate upwelling

The net coastal-ocean export of particulate organic carbon (POC), dissolved organic carbon (DOC) and chlorophyll a is studied in August 2009 at the Cape Ghir filament, a recurrent feature located within the NW African upwelling system. The estimated flux of excess total organic carbon (the non-refractory pools of DOC and POC) is about 2.1 × 109kg C y-1. DOC represents ~70% of the excess organic carbon in August 2009, during moderate upwelling. Assuming that this flux is representative of the range within a typical year, the yearly offshore net transport of total organic carbon would represent at least 29% of the primary production in this area. Since the Cape Ghir filament may extend hundreds of kilometers offshore, the associated seaward flux of organic carbon would contribute to the high microbial respiration rates reported from the nearby oligotrophic open ocean region. Our results illustrate that, when considering the regional carbon budgets of eastern boundary regions, it is imperative to take account of the offshore transport of organic matter in the numerous and recurrent upwelling filaments. © 2015 Elsevier B.V.This research was supported by the IMBER-endorsed project CAIBEX (CTM2007-66408-CO2-02) funded by the “Spanish Plan Nacional de I + D” (MEC) to EDB and JA. MB and JA were supported by the project HOTMIX (CTM2011‐30010‐C02‐01), and YSF, MB, PS, EDB, and JA, by the project PUMP (CTM2012‐33355). YSF was supported by a PhD fellowship from the Agencia Canaria de Investigación, Innovación y Sociedad de la Información (ACIISI). MB was supported by a PhD FPI fellowship from the Spanish Ministry of Science and Innovation (MICINN). EM is supported by a post-doctoral grant from the Conselleria d'Educació, Cultura i Universitats del Govern de les Illes Balears (Mallorca, Spain) and the European Social FundPeer Reviewe