Systematics, biogeography, and faunistics of selected deep-sea Harpacticoida

Despite of being the world’s largest connected environment, the deep sea remains an almost unknown region. Apart from considerable technical difficulties and problems accompanying deep-sea research, for many years man assumed that due to the governing conditions – no light, no primary production, low temperatures, extremely high pressure at high water depths – the deep sea should be a lifeless area, whose biological investigation would therefore be rather useless. Nowadays we know, however, that the deep sea houses an extraordinary richness of organisms, and sampling of deep-sea localities all around the world always provides remarkable amounts of so far unknown species.

The species diversity in the deep sea is stupendous! A study realized in the frame of the international research programme CeDAMar and dedicated to the Harpacticoida of the Angola deep-sea basin (south-eastern Atlantic Ocean) yielded the number of 682 different harpacticoiud species in an area of 0.5 m² ! Furthermore, 677 (99.3%) of these species were scientifically unknown!

Such unknown, scientifically “new” species are taxonomically described, and also investigations on systematics, the origin (biogeography), and the dispersal of species form a considerable part of my work. Moreover, I am interested in investigations on species diversity and structure of harpacticoid associations in different localities. For this purpose I apply several statistical methods (e.g. different kinds of diversity analyses, similarity analyses) which allow a characterization, as well as interregional comparison of different deep-sea communities. These comparisons provide information as to the distribution of harpacticoid species in the deep sea, and they enable me to recognize characteristic communities under certain biotic and abiotic conditions.

Fig on the right: Multiple corer returning on deck with deep-sea samples; Foto: Senckenberg/Saskia Brix-Elsig.