Surface and Hyporheic Oligochaete Assemblages in a French Suburban Stream

• DOI: 10.1007/s10750-005-1718-8
• Publication Date: 2006-05-12T13:23:12Z
• Authors: Michel Lafont; Anne Vivier; Sylvie Nogueira; Philippe Namour; Pascal Breil
• Keywords: 0106 biological sciences; OLIGOCHAETA; [SDE.MCG]Environmental Sciences/Global Changes; POLLUTION DE L'EAU; SEDIMENT; 01 natural sciences; 333; [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems; [SHS.ENVIR] Humanities and Social Sciences/Environmental studies; CHAUDANNE COURS D'EAU; [SDV.EE.ECO] Life Sciences [q-bio]/Ecology, environment/Ecosystems; [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology; SUBURBAN WATERCOURSES; OLIGOCHETE; [SDV.TOX.ECO] Life Sciences [q-bio]/Toxicology/Ecotoxicology; URBAN INPUTS; 6. Clean water; [SDE.BE] Environmental Sciences/Biodiversity and Ecology; [SDE.MCG] Environmental Sciences/Global Changes; COARSE SEDIMENTS; 13. Climate action; [SHS.ENVIR]Humanities and Social Sciences/Environmental studies; [SDV.EE.ECO]Life Sciences [q-bio]/Ecology; [SDU.STU.HY] Sciences of the Universe [physics]/Earth Sciences/Hydrology; [SDV.TOX.ECO]Life Sciences [q-bio]/Toxicology/Ecotoxicology; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; environment/Ecosystems; ZONE PERIURBAINE; ZONE HYPORHEIQUE

The Chaudanne stream received urban inputs discharged through combined sewer overflows (CSOs). The water quality was not severely impaired, with pollution mainly of organic origin. Oligochaete assemblages were studied in the coarse surface sediments and the hyporheic zone and sampled at four sites on seven occasions during 2000 and 2001. The seasonal distribution of oligochaete assemblages was analyzed by a PCA, the oligochaete species being assigned to functional traits (FTrs). Site 1, located upstream of the CSOs, was characterized by FTrs 1 and 2 (species indicating permeability and those intolerant to water pollution). Below the CSOs, high densities of oligochaetes occurred in the benthic layer of sites 3 and 4, with a predominance of FTr3 (species with tolerance to water pollution). At site 4, FTr4 species (indicative of sludge conditions) constantly predominated in the hyporheic system, but predominated in the benthos only during low stream discharges associated with peaks in CSOs. FTr3 was related to amounts of the oxidized forms of nitrogen, high stream discharges and probably to groundwater upwellings and the sludge tolerant species group (FTr4) was associated with high NH 4 + contents. We are now testing the relevance and generalization of this new approach.