doc. dr. sc. Sunčica Bosak

Loggerhead sea turtle (Caretta caretta) microbiome: insight into endozoic and epizoic communities – TurtleBIOME

Adriana Trotta, Depiction of microbiome on a turtle's back
Project code: UIP-2017-05-5635
Institution: University of Zagreb, Faculty of Science
Project duration: 01 March 2018 – 28 February 2023
Project website

Sea turtles are fascinating marine animals that are highly susceptible to human disturbance in marine ecosystems and consequently among the most endangered species in the world. Turtles are famously known for their shells, with the upper carapace harboring a complex community of epibionts such as macroalgae and invertebrates. Some of these organisms require animal substrate to live and develop and are thus exclusively epizoic and depending entirely on their hosts. Recent exciting findings show that sea turtles also harbor unique and abundant communities of diatoms – one of the most important groups of photosynthetic microorganisms present in almost all aquatic habitats. Sea turtle-associated diatoms show ability to colonize the surface of animal tissues, both skin and carapace and new species/genera have been described worldwide from all sea turtle species. In spite of their importance and essential role in the host animal physiological functions there are huge knowledge gaps on the sea turtle holobiont. Very little is known about microbes inhabiting sea turtle intestines and with no reports describing sea turtle epibiotic bacteria.

TurtleBIOME project’s scientific contribution is to provide a clear, complete and detailed image of microbial composition of the surface biofilm and the gut microbiome of loggerhead sea turtles inhabiting the Mediterranean Sea. In our research we combine metagenomic investigations of epizoic prokaryotic and eukaryotic communities with classical approach of microorganisms cultivation and light and electronic microscope observations of biofilm components. At the moment we have two PhD students and one postdoctoral student as a part of the team and we are analyzing samples collected from more than 200 loggerhead turtles collected in the cooperation with our colleagues that are dealing with different aspects of loggerhead protection and rehabilitation across the Mediterranean Sea area. Until now, we have published 10 scientific papers where we have described 13 species of epizoic diatoms new to science, we have participated at scientific conferences with 26 abstracts. We have been active in the dissemination of our scientific activity and organized an artistic workshop “Glass world on turtle’s back” in collaboration with Academy of Fine Arts as a part of the event Biology Night held at the Faculty of Science in Zagreb. We have also participated in European Researchers’ Night and held a workshop, organised by the Croatian Science Foundation. All details on our work and progress can be followed via our webpage or via our social media pages (Facebook, Twitter, Instagram)

Turtle Zoki, Centre for Recovery of Sea Turtles in Pula
Skin and shell samples

Sunčica Bosak was born on 7th June 1982 in Zagreb. She obtained her Master and Doctoral degree at the Faculty of Science, University of Zagreb where she works at the Department of Biology as an Assistant Professor. Her research area is ecology and taxonomy of marine microorganisms, especially diatoms. Her scientific collaborations include numerous international scientists, particularly the collaboration with Stazione Zoologica Anton Dohrn, Naples Italy and Botanic Garden Meise, Belgium. Her results have been published in more than 35 scientific articles and she participated in scientific conferences with more than 80 scientific abstracts.

Research team members