The 9th International Symposium on Temperate Reefs starts on 26th of June 2011 and ends the 1 of July. Main topics at this symposium are biodiversity and ecosystem functioning, management and conservation, artificial structures, contribution of reef research to general ecological theory, coldwater coral reefs, deep-sea reefs, macro-ecology and modelling, phylogeography and biogeography. Theseus will contribute to the session on artificial structures in function of flood defence.