Microbes are the catalysts and drivers of ecosystems on Earth. Despite their importance environmental microbial communities are not on the biodiversity conservation agenda. Nothing is known regarding the vulnerability and resilience of microbial communities a situation exacerbated by the inherent problem of assigning microbial activity to species identity. This knowledge is currently lacking in the global conservations efforts but is urgently needed considering the challenges that global, ecosystems are facing. The MECOMECON project proposes methane-oxidizing bacteria (MOB) as a model group of microbes to assess the hypotheses that microbial diversity is linked to ecosystem functioning. MOB catalyse a vital ecosystem service (mitigation of the greenhouse gas CH4) necessitating investigations on the impact of climate change and anthropogenic disturbance on resilience and vulnerability of these communities. In MECOMECON diversity of MOB is linked to consumption of methane using diversity profiling techniques (micro array, 454 pyrosequencing) in a range of key pristine and cultivated soils and sediments in Europe covering important methane sources. Classical macro-ecological experiments (gradients, artificial communities, removal experiments, time series after disturbance) will be carried out using the MOB communities of these habitats in order to assess resilience and vulnerability of MOB communities. The parameters obtained (active vs. inactive diversity, abundance, CH4 consumption kinetics) in the set of habitats and disturbances will be implemented in a process model incorporating microbial traits in order to predict response to disturbance from community composition. The latter is of importance for policy or management guidelines concerning questions related to greenhouse gas emissions or consumption in natural and managed ecosystems. The European Research Consortium synergises by bringing together knowledge on the process and the bacteria, expertise on experimental design and molecular diversity assessment methodology, metagenomic data handling. The habitats covered warrant the value of this work for Europe-wide impact.