Ocean currents and gradients of surface layer properties in the vicinity of the Madagascar Ridge (including seamounts) in the South West Indian Ocean

Type Article
Date 2020-06
Language English
Author(s) Vianello Patrick1, Ternon Jean-Francois2, Demarcq Herve2, Herbette Steven3, Roberts Michael J.1, 4
Affiliation(s) 1 : UK-SA NRF/DST Bilateral Research Chair: Ocean Sciences and Marine Food Security, Nelson Mandela University, Port Elizabeth, South Africa
2 : MARBEC, IRD, Univ Montpellier, CNRS, Ifremer, Sète, France
3 : Laboratoire d’Océanographie Physique et Spatiale (LOPS), IUEM, Univ. Brest - CNRS - IRD - Ifremer, Brest, France
4 : National Oceanography Centre, Southampton, United Kingdom
Source Deep-sea Research Part Ii-topical Studies In Oceanography (0967-0645) (Elsevier BV), 2020-06 , Vol. 176 , P. 104816 (13p.)
DOI 10.1016/j.dsr2.2020.104816
Keyword(s) South West Indian Ocean, Madagascar Ridge, Seamounts, Walters shoal, Sea surface temperature, Eddy kinetic energy, Mixed layer depth, Chlorophyll-a, Geostrophic currents
Abstract

This work is part of the MADRidge Project special issue which aims to describe pelagic ecosystems in the vicinity of three prominent shallow seamounts in the South West Indian Ocean: one here named MAD-Ridge (240 m below the surface) plus Walters Shoal (18 m) on the Madagascar Ridge, and La Pérouse (60 m) on the abyssal plain east of Madagascar. The three span latitudes 20°S and 33°S, some 1500 km. The study provides the background oceanography for the once-off, multidisciplinary snapshot cruise studies around the seamounts. As life on seamounts is determined by factors such as summit depth, proximity to the light layers of the ocean, and the ambient circulation, a first description of regional spatial-field climatologies (16–22 years) and monthly along-ridge gradients of surface wind (driving force), water column properties of sea surface temperature, mixed layer depth, chlorophyll-a and eddy kinetic energy, plus ocean currents is provided. Being relevant to many applications in the study domain, these properties in particular reveal contrasting environments along the Madagascar Ridge and between the three seamounts that should drive biological differences. Relative to the other two seamounts, MAD-Ridge is in the more extreme situation, being at the end of the East Madagascar Current, where it experiences sturdy, albeit variable, currents and the frequent passing of mesoscale eddies.

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Vianello Patrick, Ternon Jean-Francois, Demarcq Herve, Herbette Steven, Roberts Michael J. (2020). Ocean currents and gradients of surface layer properties in the vicinity of the Madagascar Ridge (including seamounts) in the South West Indian Ocean. Deep-sea Research Part Ii-topical Studies In Oceanography, 176, 104816 (13p.). Publisher's official version : https://doi.org/10.1016/j.dsr2.2020.104816 , Open Access version : https://archimer.ifremer.fr/doc/00634/74581/