engleski

Metagenomic characterization of the surface biofilm on mediterranean loggerhead sea turtles

The external surfaces of marine vertebrates provide suitable hard substrata for the growth of rich microbial biofilms. Many aspects of turtle ecology and behavior are still unknown and the micro-epibionts may be used as an indicator of the animal behavioral pattern or as a proxy of the anthropogenic impact to coastal marine habitats of this species. However, the composition of these surface micro-communities is largely unknown. In recent years, numerous studies apply DNA metabarcoding approach using 16S and 18S amplicons to analyze different types of communities in various environments such as the surface layer of the ocean, sediments, and animal biofilms. In our study, we analyzed carapace and skin biofilm samples of ten loggerhead turtles (Carreta carreta) collected from distinct habitats in the Mediterranean Sea, along the Croatian and Italian coast of the Adriatic Sea and Amvraikos Gulf in Greece. The composition of OTUs representing bacterial communities living on the carapace and the skin were highly similar among both the Greek and Adriatic turtles reflecting taxa that are most abundant in the marine ecosystems such as proteobacteria (alpha, beta, gamma and delta), cyanobacteria, actinobacteria and bacteroidetes. The results of 18S amplicon analysis showed more variation between the Greek and Adriatic turtles, including different ratios of taxa which occupied the skin and the carapace. Eukaryotic OTUs that mostly dominated across samples were those of green, brown and red algae, crustaceans, ciliates and diatoms. This study provides valuable insights into how microbial taxa associated with animal surface biofilm vary among surface types and habitats which loggerheads utilize in the Mediterranean Sea.

diatoms ; metabarcoding ; loggerheads

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