To celebrate 2010 as the United Nations International Year of Biodiversity and the importance of sharing our knowledge of the diversity of the natural world, we present a cross journal thematic series of open access biodiversity research. This selection highlights leading research from the disciplines of genetics and evolution of species richness, to conservation and biodiversity informatics. BMC Ecology expands scope (BMC Ecology 2010, 10:16) BMC Ecology has always been open to a wide range of topics from biodiversity research and in this 2010 International Year of Biodiversity we are keen to emphasise biodiversity studies within the scope of the journal. Rescued chimpanzees (BMC Ecology 2010, 10:2) The geographic origins of 46 chimpanzees who found refuge at the Limbe Wildlife Centre are traced by genotyping, indicating that hunting and the smuggling of live animals is widespread throughout Cameroon. Metazoa living without oxygen (BMC Biology 2010, 8:30) An expedition to a deep sea hypersaline anoxic basin in the Mediterranean has discovered the first multicellular animals that live and reproduce in the absence of oxygen.