The research encompass many various aspects of benthic infaunal processes: effects of faunal bioturbation and irrigation activity in differnet faunal successional stages on sediment chemistry; trapping and transformation of organic matter by different functional groups population interspecific competition effects of oxygen deficiency on benthic habitat succession and infaunal behaviour analysed by in situ sediment profile imaging and in laboratory experimets the importance of infaunal activity and food quality on the fate of organic contaminants chemical communication in amphiurid (brittle-star) populations.