Compl\ue9ments \ue0 l\u27\ue9tude syst\ue9matique des Ischnomesidae (Isopodes Asellotes) de l\u27Atlantique. Description de quatre esp\ue8ces nouvelles

Volume: 257Start Page: 1537End Page: 155

Les Haploniscidae (Crustac\ue9s Isopodes Asellotes) de l\u27Atlantique. Description de huit esp\ue8ces nouvelles

Volume: 243Start Page: 1137End Page: 116

Isopodes nouveaux des campagnes Bia\ue7ores et Biogas IV en Atlantique Nord

Volume: 303Start Page: 689End Page: 70

La famille des Haploniscidae (Isopodes, Asellotes) : discussion syst\ue9matique et phylog\ue9nique

Volume: 476Start Page: 889End Page: 90

\uc9tude biom\ue9trique des variations intrasp\ue9cifiques chez l\u27Isopode Janirella bonnieri Stephensen, 1915, par l\u27analyse canonique

Volume: 36Start Page: 363End Page: 37

Investigation into the ecology of the ormer (

The factors affecting spatial distribution of the ormer (Haliotis tuberculata L.) in the vicinity of Saint-Malo (northern Brittany, France) are analyzed using a multivariate approach. A correspondence analysis is applied to a contingency table based on 200 samples. Ormers are always absent from smooth rocky substrata, exposed to a strong current or deeper than 8 m below low chart datum. Abundance and biomass of H. tuberculata are distributed along a gradient correlated with an increasing complexity of habitat and a reduction of current. Otherwise, no correlation has been found between characteristics of ormer distribution and surge, depth or large and turf algae

Carbon flows in a subtidal fine sand community from the western Encrlish Channel: a simulation analysis

Organic carbon flows through the Pierre Noire fine sand community (Bay of Morlaix, France) are described with a trophodynamic point model, Data collected during several annual cycles are used to calibrate the seasonal variations of each benthic compartment. Mean annual values of state variables are correctly simulated. In a first approach, the seasonal variations were simulated using 2 forcing functions: input of energy and temperature influence. In a second run, spawning and recruitment effects were introduced as regulating factors for the macrobenthic compartments. The resulting annual carbon budget synthesizes the information we have on this common type of ecosystem. Phytoplankton production represents the major food supply to the benthic system and the importance of pelagic-benthic coupling in this area is confirmed. A large proportion of the carbon input is consumed by bacteria which is the main trophic source for meiofauna. Meiofauna is an important link between the bacteria + detritus and the carnivore level, and cannot be considered as an independent food web. The significance of regulation factors such as spawning and recruitment processes in the dynamics of the macrofauna is explored

The paradox between the long-term decrease of egg mass size of the calanoid copepod Eurytemora affinis and its long-term constant abundance in a highly turbid estuary (Gironde estuary, France)

Eurytemora affinis egg mass size-a commonly used demographic parameter-was surveyed in the Gironde estuary. Its decrease between 1978 and 2003 contrasted with the stability of population density during this long-term period. Different hypotheses were tested to explain this paradox. (i) Upstream shift of the population: Even though the population of E. affinis shifted upstream due to a greater penetration of marine water, no relationship between the population shift and demographic parameters was observed: the egg mass size exhibited the same evolution upstream. (ii) Water warming: No early egg production and no change of female size that could metabolically limit the egg mass size was observed. (iii) Food limitation: The change in food quality observed did not result in any change in total copepod abundance. (iv) Faster renewal of egg masses: The paradox cannot be explained by this factor and the number of adults observed nowadays is higher than the number of eggs produced by females, whereas fecundity rates strongly increased. The paradox is probably explained by the expulsion of viable subitaneous eggs. This may represent a recent behaviour adaptation of the copepod to environmental changes

Structure et fonctionnement des peuplements benthiques du Bassin d'Arcachon

La macrofaune benthique du domaine subtidal et du domaine intertidal du Bassin d'Arcachon, lagune côtière atlantique du sud-ouest de la France, a été étudiée de manière qualitative et quantitative. Dans un premier temps, les principaux peuplements de macrofaune benthique ont été identifiés et décrits. Les relations entre ces peuplements et les principaux facteurs du milieu ont été mis en évidence. A partir de ces résultats, une cartographie des peuplements benthiques de la lagune a été réalisée. Dans un deuxième temps, deux autres composantes du benthos : la méiofaune et la flore bactérienne ont également fait l'objet d'une étude quantitative. En se basant sur la structure des biocénoses benthiques et leur distribution dans la lagune, un bilan équilibré des flux trophiques au sein du benthos a été réalisé. Deux bilans séparés ont été établis, l'un concernait le domaine intertidal et l'autre, le domaine subtidal. L'ensemble des résultats obtenus permet d'émettre un certain nombre d'hypothèses sur le fonctionnement de l'écosystème.BORDEAUX1-BU Sciences-Talence (335222101) / SudocBORDEAUX1-Lab.Océanogr.Arcacho (330092101) / SudocSudocFranceF