Lacustrine, profundal meiobenthic oligochaetes as indicators of trophy and organic loading

The distribution of meiobenthic and macrobenthic oligochaetes in Paijanne lake, Finland, was investigated. Two depths (20 m and maximum) were sampled at each of 10 stations. The top 5 cm of sediment were sampled. A total of 1546 individuals of oligochaetes belonging to 20 taxa were identified. The influence of environmental factors on oligochaetes was similar at the 2 depths sampled. Numbers of Piguetiella blanci, Aeolosoma quaternarium and Aeolosoma hemprichi were indicators of oligotrophic conditions, whilst numbers of Amphichaeta leydigii, Speicaria josinae and Vejdovskyella comata were indicators of eutrophic conditions. Total oligochaete abundance or biomass values were poor indicators of eutrophic conditions. Cluster analysis of the data showed that clustering of sampling stations based on oligochaete variables generally corresponded to clustering based on environmental data.