Investigators: Jean-François Ternon (IRD, Réunion) and Sven Kaehler (Rhodes University, South Africa)
MAP OF STUDY SITES
Click on the white-marked areas to see a close-up on the study sites.
The influence of mesoscale (~100 km) ocean dynamics on the biological productivity of marine ecosystems appears more and more evident due to recent means of synoptic and regular observation of the oceans (satellite observations). The Mozambique Channel ocean dynamics is strongly constrained by mesoscale features.
Eddies are formed at the narrowest and shallowest part of the Channel (~16°S) and migrate southwards along the western side of the Channel along the coasts of Mozambique and South Africa. Eddies originating from the south Madagascar also migrate northwards along the eastern side (west coast of Madagascar) of the Channel. During their displacement, eddies strongly influence marine ecosystems due to associated physical processes that promote vertical exchanges and, consequently, primary production. This biological signature is expected to propagate through the whole trophic web, as evidenced by recent observations (until top predators). Studies to date also suggest that eddies may promote larval retention and coastal larvae dispersion toward the high sea.
The aims of this project are to investigate coastal – high sea ecosystem functioning and exchanges directly linked to the eddy dynamics within the Mozambique Channel. Issues (not exhaustively listed here) related to the export of coastal primary production toward the middle of the Channel, both along Mozambique and Madagascar, the influence of eddy dynamics on larval retention or aggregation, the signature of eddies in the spatial distribution of forage fauna or top predators, will be addressed during MESOBIO.
Our project is based on the achievement of three scientific cruises in the Mozambique Channel (2009, 2010 and 2011), within the framework of regional programmes (french IRD and MCM programmes, ASCLME). These joint cruises will be possible due to complementary skills from the different scientific teams. The repetition of the cruises will enable us to explore different eddies pair locations (on the east and west sides of the channel), at different seasons and for different eddies characteristics (for instance, newly formed eddies versus older and “mature” ones).
An important part of the work will consist in the collaborative analysis of the results, both in terms of international partnerships and in terms of scientific multi-disciplinary collaboration. The first scientific syntethis will concern the results of the ASCLME 2008 Leg 4 and will be presented at the Sixth WIOMSA symposium in August 2009. Scientific publications in peer review journals will result from the collaborative work conducted during the whole MESOBIO project.
Application of this research effort to bordering countries issues will consist in a better knowledge of marine ecosystems which is necessary to promote protection, development and sustainablity of coastal areas. Indeed, eddies migrating along the shelves are very constraining for coastal ecosystems. New information should also been obtained on coastal fish larvea export and exchanges form place to place at different sites of the Channel (diversity and conservation issues).
The project will also promote capacity building with the participation of regional trainees at the cruises as well as with the organisation of a training course (university of la Réunion, July 2010), about relationships between environment and living resources in the context of the SWIO and Mozambique Channel ecosystems. Post-graduate and post-doctoral opportunities linked to the intensive field work are also expected.