%0 Journal Article %J Italian Journal of Zoology %D 2006 %T Summer disease in Parazoanthus axinellae (Schmidt, 1862) (Cnidaria, Zoanthidea) %A Cerrano %A Totti %A Sponga %A Bavestrello %K benthos %K biodiversité %K biodiversity %K changement climatique %K climate %K climate change %K cnidarian %K cyanobactérie %K cyanobacterium %K disease %K global warming %K Italie %K Italy %K Ligurian Sea %K mass mortality %K Mediterranean sea %K Méditerranée nord-occidentale %K Méditerrannée occidentale %K Mer Ligure %K Mer Méditerranée %K monitoring %K mortalité massive %K north-western Mediterranean %K Parazoanthus axinellae %K pathogen %K pathogène %K Portofino %K réchauffement global %K sponge %K western Mediterranean %V 73 %X

Climate change is affecting marine environments all over the world but scientists' attention is mainly devoted to tropical areas. In the Mediterranean Sea, species with a cold affinity are decreasing very fast from 0 to 40m depth, while warm water species increase. From 2000, several populations of the zoanthid Parazoanthus axinellae (Schmidt 1882) have been showing signs of suffering along the Ligurian coast. Here we report a three-year monitoring, from June 2001 to September 2003, of a population of P. axinellae on the rocky cliff of the Portofino Promontory (Ligurian Sea). During this span of time the population, which covered an area of several square metres with a density of about 1 polypcm22, was severely reduced. In the meanwhile an encrusting sponge, Crambe crambe, rapidly colonized the free substrates abandoned by the zoanthid. Warm water and the massive proliferation of a cyanobacterium attributed to the genus Porphyrosiphon are hypothesized to be the main causes of this disease.