Claude Rougier
University of Montpellier
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Featured researches published by Claude Rougier.
Hydrobiologia | 1997
Roger Pourriot; Claude Rougier; Anne Miquelis
Zooplankton composition and growth in the river Marne (France)were studied on a space scale of 300 km in July 1991. There werethree distinct areas along the river: the immediate reservoir outlet(pK 652), the natural river called middle Marne (from pK 652to pK 799 downstream) and the channeled river (from pK 799 topK 975 downstream). A typical lake community, characterized both byan abundance of microcrustaceans and a high zooplanktonconcentration was found immediately downstream of the reservoir Marne(Der-Chantecocq Lake). Here, large microcrustaceans (copepods,daphnids), and large rotifers (Keratella cochlearisrobusta and Polyarthra dolichoptera-vulgaris) rapidlydisappeared, and small rotifer species (<120 μm) dominated theplankton. Their populations (specially Keratella c. cochlearis)proliferated in the middle Marne as far as 100 km downstream(up to 288 ind. l-1) but were considerably reduced (20 to35 ind. l-1) where the river is channeled, algal resourcesdecline and turbidity increases.The dominance of small organisms such as rotifers, in riverplankton is assumed to be the result of fish predation on largezooplankton as well as of a short generation time which allowstheir in situ reproduction, in spite of a short residencetime of the water.
Hydrobiologia | 1998
Anne Miquelis; Claude Rougier; Roger Pourriot
The impact of turbulence and turbidity on Brachionus calyciflorus grazing rate was determined in short feeding periods (10 min), using labelled Chlorella pyrenoïdosa. The response to water motion of B. calyciflorus depends on it physiological state: the grazing rate of recently fed amictic females stomach green (with one or two eggs) is significantly reduced in agitated environments compared with non-agitated environments. In contrast, the grazing rate of starved amictic females is not reduced by water motion, whatever its velocity (V1=0.18 m s−1 and V2=0.22 m s−1). In the presence of suspended particles (3–6-μm silica beads), a larger reduction in grazing rate is observed in agitated water at any water velocity (V1=0.18 m s−1 or V2=0.22 m s−1), than in stagnant water. A synergy between turbulence and turbidity is unfavourable to feeding of rotifers.
Water Research | 2001
Thong Lam-Hoai; Claude Rougier
The authors proposed to examine zooplankton biomass at three stations inside (T and Z) and outside (M) a coastal lagoon of the north-western Mediterranean Sea. Station T represented the lagoon central area, and station Z was positioned in a shellfish farming sector, while the seaside station (M) served as a reference of marine environment. Analyses were designed to outline the net zooplankton assemblages (taxonomic structures and length distributions) in different environmental conditions, including the farming activity. A discriminant analysis of environmental variables determined that temperature, salinity and phytoplankton implied mainly in spatial pattern of the samples. An ordination of taxa biomasses showed two main factors which might contribute to the organisation of the zooplankton assemblages: the geographical position and the thermal period. The geographical position integrated the lagoon-sea water exchange under forcing parameters (habitat, tides and winds). The thermal period reflected both the populations development cycles and the environmental constraints (temperature, salinity, trophic resources). The resulting effects appeared in structured zooplankton assemblages in space and time. The number of 50 microns interval length classes and of taxa decreased from the seaside and the lagoon central area free of farming activity to the shallower farming zone. But the biomass-length distribution profiles did not closely follow such an expected opposition between opened and confined areas: more extended profiles were observed at station Z. Biomass dominant size classes concerned the range up to 300 microns. This size category appeared to collapse in terms of biomass from the seaside or central area of the lagoon towards the farming area, similarly to zooplankton global biomass fluctuations. Difference between biomass levels and between biomass structures suggested that net zooplankton partly acted as food competitors of macro-filtering organisms, and as preys for farming shellfish and associated epifauna. This impact mainly concerned microzooplankton populations.
Hydrobiologia | 2000
Claude Rougier; R. Pourriot; T. Lam-Hoai
During a survey of a north-western Mediterranean coastal lagoon, (the Etang de Thau, and at a nearby marine station, 1994–1998), six species of the genus Synchaetawere identified. The systematics of this illoricate genus is difficult and identification is virtually impossible in preserved material, although some indication may be obtained from an examination of the trophi after treatment with sodium hypochlorite. In this study, taxonomic characters (mastax, body morphology and egg size) were obtained from living material prior to preservation. We add some ecological observations: distribution of species (neither temperature nor salinity were found to be determining factors), co-existence (up to five species can co-occur) and consideration of trophic links (competition with tintinnids, copepod nauplii and cirripedes).
Marine Ecology Progress Series | 2000
Christine Dupuy; André Vaquer; Thong Lam-Hoai; Claude Rougier; Nabila Mazouni; Jacques Lautier; Yves Collos; Solange Le Gall
Estuarine Coastal and Shelf Science | 2006
T. Lam-Hoai; D. Guiral; Claude Rougier
Marine Ecology Progress Series | 1997
Thong Lam-Hoai; Claude Rougier; Gerard Lasserre
Hydrobiologia | 2005
Yves Collos; Julie Husseini-Ratrema; Béatrice Bec; André Vaquer; Thong Lam Hoai; Claude Rougier; Virginie Pons; Philippe Souchu
Estuarine Coastal and Shelf Science | 2005
Claude Rougier; R. Pourriot; T. Lam-Hoai; D. Guiral
Annales De Limnologie-international Journal of Limnology | 1991
Roger Pourriot; Claude Rougier