Facing the high species richness of deep-sea sediments, the questions arise which processes produce and maintain diversity and at which spatial scales do they operate?The supposed small-scale habitat structure of deep-sea sediments provides the background of this study. Biogenic structures create a heterogeneous environment that might influence the structure of the communities and the dynamics of the populations of benthic meiofauna organisms. As an example for biogenic structures, the influence of deep-sea sponges on small-scale distribution patterns of benthic deep-sea nematodes was investigated. Diversity patterns of the nematode communities around the sponges and from control sediments were described. From the great variety of aspects of diversity, functional diversity for the nematode community structure were measured and described. To estimate functional diversity of the nematodes, organisms were divided into life-form types by means of the structure of buccal cavity (four groups) as well as tail shape and body shape (five groups each). These connectable criteria are considered as morphological adaptation to a given life-style and are the basis for the creation of functional groups. Based on this classification a total of 100 trait combinations are possible. Our study revealed, that the total number of approx. 5800 individuals which are distributed over 367 species, were represented by 52 functional groups within the entire nematode community. Overall the nematode community from the sponge samples show a higher functional divergence and thus a high degree of niche differentiation. Within the nematode community from the sponge cores, a stronger interaction between the species and a higher functional diversity seems to allow a larger extend of resource utilisation. The more homogeneous habitat conditions, in the control sediments seem to offer less micro-habitats (refuges) or ecological niches respectively, compared to the more heterogeneous habitat conditions of the sediments around the sponges.