Epipelagic mesozooplankton distribution and abundance over the Mascarene Plateau and Basin, south-western Indian Ocean

Gallienne, CP, Conway, DVP, Robinson, J, Naya, N, Williams, JS, Lynch, T and Meunier, S 2004 Epipelagic mesozooplankton distribution and abundance over the Mascarene Plateau and Basin, south-western Indian Ocean. Journal of the Marine Biological Association of the United Kingdom, 84. 1-8. https://doi.org/10.1017/S0025315404008835h

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The crescent shaped Mascarene Plateau (southwestern Indian Ocean), some 2200 km in length, forms a partial barrier to the (predominantly westward) flow of the South Equatorial Current. Shallow areas of the Mascarene Plateau effectively form a large shelf sea without an associated coastline. Zooplankton sampling transects were made across the plateau and also the basin to the west, to investigate the role the partial interruption of flow has on zooplankton biomass and community structure over the region. Biomass data from Optical Plankton Counter (OPC) analysis, and variability in community structure from taxonomic analysis, appear to indicate that the obstruction by the plateau causes upwelling, nutrient enrichment and enhanced chlorophyll and secondary production levels downstream. The Mascarene Basin is clearly distinguishable from the ridge itself, and from the waters to the south and north, both in terms of size-distributed zooplankton biomass and community structure. Satellite remote sensing data, particularly remotely-sensed ocean colour imagery and the sea surface height anomaly (SSHA), indicate support for this hypothesis. A correlation was found between OPC biovolume and SSHA and sea surface temperature (SST), which may indicate the physical processes driving mesozooplankton variability in this area. Biomass values away from the influence of the ridge averaged 24 mg m-3, but downstream if the ridge biomass averaged 263 mg m-3. Copepods comprised 60% of the mean total organisms. Calanoid copepods varied considerably between regions, being lowest away from the influence of the plateau, where higher numbers of the cyclopoid copepods Oithona spp., Corycaeus spp. and Oncaea spp., and the harpacticoid Microsetella spp. were found.

Item Type: Publication - Article
Additional Keywords: Geographical distribution, Mascarene Plateau, Indian Ocean, Optical plankton counter Zooplankton Community composition Abundance Plankton surveys
Divisions: Marine Biological Association of the UK > Other (MBA)
Plymouth Marine Laboratory > Other (PML)
Depositing User: EPrints Services
Date made live: 07 Aug 2006
Last Modified: 25 Apr 2020 09:54
URI: https://plymsea.ac.uk/id/eprint/1309

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