Morphometry, energetics and diversity of free-living nematodes from coasts of Bizerte lagoon (Tunisia): an ecological meaning

摘要

Analyses of water quality in the Bizerte lagoon showed their relative low oxygenation during September 2002 compared to December 2001. Sediment variables appeared directly dependent on the silt/clay distribution and sewage from the metallurgic factory "El Fouledh". Nematode abundances were negatively influenced by silt/clay, organic matter, metals and chlorophyll a content. The individual nematode body size was clearly related to the distribution of two dominant species, Terschellingia longicaudata (Linhomoeidae) and Paracomesoma dubium (Comesomatidae). Shannon-Wiener diversity index values were the lowest in the South-Western stations characterized by higher level of organic matter and a weaker effect of pollution, in "Baie des carrieres" and "Menzel Jemil" areas. The sediment metals were the key factors controlling the respiration rate of meiobenthic nematodes.