Bacterial biofilms on Cancer pagurus

To get an insight of potential effects of climate change and temperature raises on the spread of crustacean shell disease, we analyzed the biofilm composition on the carapace of brown crabs Cancer pagurus from two different populations. Individuals at the German area of the North Sea (Helgoland island) and 1,500 km farther north in Norway were kept under natural and experimentally changed temperature regimes. We contribute a detailed picture on the epibiotic bacterial biofilm by using next generation sequencing technology on 25 biofilms from 13 C. pagurus individuals. We found bacterial communities as a combination of taxa known for other marine crustaceans and taxa associated to other surfaces. The highest similarities in community composition were observed between samples taken from one individual. Communities showed strong similarities with biofilms studied in North American lobsters. Short exposure (5 days) to changing temperature regimes had no effect on the prevalence of shell disease but on the diversity of epibiotic biofilm communities. We found temperature dependent differences in abundance of taxa such as the Flavobacteriia, Gammaproteobacteria or Deltaproteobacteria in combination with a decrease in alpha diversity under cold conditions. This study represents the first overview of C. pagurus normal epibiotic biofilms and biofilms treated with different temperatures as a basis to study the potential spread of shell disease syndrome in C. pagurus and monitor epibiotic communities in populations considering future climate change.