• Micro/mesocosm studies (studies in model ecosystems) with sediments and soils can be applied to assess effects of chemicals on higher ecological levels, but still under controlled and replicated conditions. Therefore, micro- and mesocosm represent a link between laboratory single species toxicity tests and field studies and may provide supporting argumentation for reduction of assessment factors in the environmental risk assessment of chemicals (e.g. Weyers et al. 2004; Van den Brink et al. 2005).  
• Nematodes can be part of larger mesocoms studies, but also of low cost, small-scale microcosms, because already a few gram of sediment or soil contain enough nematodes to ensure a statistically sound assessment. This allows for testing effects of chemicals on nematode communities in miniture systems. 

Ecossa provides:  

• Indoor Freshwater Mikrokosm Studies: approx. 600 g of sediment
• Indoor Soil Microcosm Studies: approx. 30 g of soil
• Analysis of meiofauna and nematode communities from mesocosm studies (sample extraction; quantitative analysis of meso/meiofauna; taxonomic identification of chironomids and nematodes at species level)