An assessment of the spatial heterogeneity of environmental disturbance within an enclosed harbour through the analysis of meiofauna and nematode assemblages

Significant spatial heterogeneity in the abundance and composition of meiofaunal and nematode assemblages was described inside the Genoa-Voltri harbour (Genoa, Italy) in relation to variation in the main environmental variables. In harbour sediments characterized by low Eh values and high organic matter concentrations, total meiofauna abundance was lower (948 919 ind 10 cm2), nematode individual biomass was higher (0.17 0.07 mg C), kinorhynchs and tanaids were completely absent, and the nematode assemblage was dominated by the genera Terschellingia, Sabatieria ( pulchra group) and Paracomesoma. In contrast, in sediment characterized by lower levels of organic pollution, meiofaunal abundance was higher (1085 737 ind 10 cm2), nematode individual biomass was lower (0.11 0.04 mg C), kinorhynchs and tanaids were present and the nematodes were dominated by the genera Desmodora, Daptonema, Anticoma and Halalaimus. Environmental disturbance as assessed by the analysis of meiofaunal and nematode assemblages and sediment environmental variables changed significantly over a scale hundreds of meters, but did not follow a gradient from the inner to the outer harbour. Analysis of nematode assemblages is proposed as a useful tool for the identification of environmental risk areas which may assist in the development of good planning, monitoring programmes and better management of harbour ecosystems.