Meso- and macrozooplankton composition patterns related to hydrodynamic structures in the Ligurian Sea (Trophos-2 experiment, April-June 1986)

S Pinca,S Dallot

doi:10.3354/meps126049

Abstract

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 126:49-65 (1995) - doi:10.3354/meps126049 Meso- and macrozooplankton composition patterns related to hydrodynamic structures in the Ligurian Sea (Trophos-2 experiment, April-June 1986) Pinca S, Dallot S The distributional patterns of zooplanktonic fauna based on samples taken during the Trophos-2cruise (spring 1986) in the westernLiguro-Provençal Basin, Mediterranean Sea, are de-scribed. This region is permanently exposed to a cyclonic circulation with an associated thermohaline front which encloses a central divergence zone. In the middle of this central area, we encountered a mesoscale (about 70 km diameter) anticyclonic eddy. Taking into account the hydrological structure of the 0 to 200 m upper level, the area could be divided into 4 zones: (1) peripheral and frontal, (2) central Riviera, (3) central Corsica and (4) the eddy. These zones differed in the abundance of several zooplankton species. In particular, some of them showed a higher concentration in the eddy, such as the radiolarian Aulacantha scolymantha, the euphausiid calyptopis larvae, and the copepods Centropages typicus, Pleuromamma gracilis, Mesocalanus tenuicornis, Heterorhabdus papilliger and Euchirella rostrata. We suggest the central eddy is a favorable environment for these large species. Thus, increased primary and secondary production due to the influence of hydrodynamic phenomena appears not to be limited to the frontal zone. Within the eddy, zooplankton growth could be enhanced, thus favoring export production. To detect zooplankton species assemblages, the stations have been clustered into 5 groups based on their taxonomic composition and abundance. These groups had a rather good geographic coherence although they had a more complex distribution than the physical structure. This higher variability of spatial organization of the 5 plankton assemblages can be explained by behavioral and trophic phenomena. Zooplankton . Hydrodynamics . Q-mode classification . MDS Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 126. Publication date: October 05, 1995 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1995 Inter-Research.

Highlights

Numerous studies have demonstrated the regulation of planktonic ecosystems by physical oceanic processes (Denman & Powell 1984, Legendre & Demers 1984);the quality and intensity of this dependence is often strongly signaled in the spatial pattern of plankton biomass and species composition (Mackas et al 1985)
Clear examples of physical features which show an influence on the distributions of zooplankton and ichthyoplankton
The Ligurian Sea is a part of the Liguro-Provencal Basin (Gostan 1968), which includes the Provencal coasts, the French Riviera and the northwestern Corsican coasts. This region is characterized by the cyclonic Ligurian Current, whose geostrophic flow is induced by thermohaline variations (Bethoux et al 1982) and influenced by winds and the particular orographic canalization of Atlantic water (Esposito & Manzella 1982, Marullo et al 1985)

Summary

Introduction

Numerous studies have demonstrated the regulation of planktonic ecosystems by physical oceanic processes (Denman & Powell 1984, Legendre & Demers 1984);the quality and intensity of this dependence is often strongly signaled in the spatial pattern of plankton biomass and species composition (Mackas et al 1985). The Ligurian Sea (northwestern Mediterranean Sea) is a part of the Liguro-Provencal Basin (Gostan 1968), which includes the Provencal coasts, the French Riviera and the northwestern Corsican coasts. This region is characterized by the cyclonic Ligurian Current, whose geostrophic flow is induced by thermohaline variations (Bethoux et al 1982) and influenced by winds and the particular orographic canalization of Atlantic water (Esposito & Manzella 1982, Marullo et al 1985). Plankton studies have concentrated on the influence of the front on the horizontal and vert~caldistributions of different species and developmental stages of zooplankton organisms (Licot et al 1983,Boucher 1984,Boucher et al 1987,Ibanez & Boucher 1987, Laval et al 1989, Gorsky et al 1991, Laval et al 1992)

Objectives

Findings

Discussion

Conclusion