Μελέτη της δομής και διανομής των ταξοκοινωνιών των Πολυχαίτων στην περιοχή εξόδου του υποθαλάσσιου αγωγού λυμάτων της πόλης του Ηρακλείου
Polychaeta Annelida are present in the majority of benthic marine ecosystems. They often comprise over one third of macrobenthic species and may be even more predominant. The polychaete assemblages of the infralittoral zone in front of the underwater sewage outfall in the gulf of Heraklio (Crete, Greece) was studied. Samples were collected from 7 different sites on soft substrata at depths ranging from 10-40m. The fauna consisted of 7362 specimens belonging to 163 species. 5 species were of zoogeografical interest. Organismic assemblages were defined based on the polychaete taxocene according to the system proposed by Peres & Picard. Uni- and multivariate statistical methods (diversity indices, classification, ordination, SIMPER, ANOSIM, geometric abundance/size classes, ABC curves, BIOENV) were applied in order to study the polychaete assemblages structure and the level of disturbance of the area. Biological features such as number of species, diversity, biomass, diversity indices, feeding guilds, were correlated with the sediment type and several other environmental factors (Eh, ATP, pigments). The factors which best correlated with the distribution pattern of the polychaete assemblages were temperature and particulate organic matter (POC). The statistical methods applied gave no significant indication for the characterization of the sites as disturbed as far as the polychaete community is concerned.