Seasonal dynamics of the zoobenthic communities in the mesohaline zone of the Loire estuary (France) |
| |
Authors: | Jocelyne Marchand Didier Gascuel |
| |
Institution: | (1) Laboratoire de Biologie Marine, Université de Nantes, 2, rue de la Houssiniere, 44072 Nantes-Cedex 03, France;(2) Laboratoire de Biologie Halieutique, ENSA, 65, rue de St. Brieuc, 35042 Rennes-Cedex, France |
| |
Abstract: | The application of correspondence factorial analysis to four types of sediment in the upper reaches of the Loire estuary enabled the significance of environmental factors in the spatial distribution, abundance and seasonal dynamics of the biotic communities to be determined. In coarse sand, the communities are stable but species are few in number and population densities are low. In muddy sediments (from muddy sand to fluid mud) population densities are high but undergo seasonal fluctuations due to changes in the hydrological regime (especially the dissolved oxygen regime). This is true for the composition of the biotic communities. The oligohaline phase, in which the fluvial element is predominant, is characterized by abundance maxima due to freshwater species. The mesohaline phase, in which the marine element is predominant, exerts a restrictive action on population densities; certain species are supplanted by others, their development being governed by the quality of the environment. |
| |
Keywords: | estuary upper reaches zoobenthos seasonal dynamics |
本文献已被 SpringerLink 等数据库收录! |
|