Summary of Abstract Submission

Abstract Submission No. IO50-04-0044PresentationOral

MESOBIO: MESOSCALE DYNAMICS AND ECOSYSTEM RESPONSES IN THE MOZAMBIQUE CHANNEL

TERNON Jean-François*1, MARSAC Francis1, BARLOW Raymond G.2, MENARD Frédéric1, ROBERTS Michael J.3

1 Institut de Recherche pour le Développement, France
2 Bayworld Centre for Research and Education, South Africa
3 Department of Environmental Affairs, South Africa

ABSTRACT :

The MESOBIO project, funded by the WIOMSA, was conducted in 2009-2010 to investigate the biological and trophic signature of the mesoscale eddy field within the Mozambique Channel. Based on multi-disciplinary cruises some conducted prior (2007 and 2008, within the South-African ACEP and the ASCLME programs) and during MESOBIO, the joint team from France, South-Africa, Mozambique and Madagascar achieved an integrated study of the eddy dynamics, the biogeochemical response of the 1000m surface layer, the phytoplankton and zooplankton communities, the intermediate trophic level (micronekton) as well as seabirds. Complementary sampling (within the SWIOFP program) allowed investigating the exploited marine top predators (tunas and swordfish). The observations confirmed that a well structured eddy field governs the surface and subsurface circulation in the Mozambique Channel. Upwelled nutrients in the center of cyclonic eddies were found to enhance primary production at the deep chlorophyll maximum. At the surface, the main influence on chlorophyll was from the advection of coastal production into the channel by eddies propagating along the Mozambique slope. As expected, the phytoplankton and zooplankton distribution was closely related to the eddy field while, for micronekton, eddy history has to be considered when looking for eddy related distribution. Top predators relationships to the eddy field was found to depend on the species feeding habits and flying capabilities (seabirds). Experiences based on high resolution regional physical and biogeochemical models allow an improved understanding of the ecosystem response to eddy forcing. The MESOBIO results have been published in Deep-Sea Research II (volume 100, February 2014).