The scientific schooner Tara has recently launched the Tara Coral Expedition. Over the next 18 months, a consortium of more than 40 institutions and 67 scientists will study reefs in the Coral Triangle — known as “the Amazon of the ocean” — in the western Pacific, one of the world’s main epicentres of marine biodiversity and also one of the regions most vulnerable to ocean warming and acidification.

The aim of Tara Coral is to understand why and how some coral reefs in the region are able to withstand global warming. Identifying the factors that explain this resilience will help guide more effective conservation strategies to halt the massive loss of reefs worldwide. This is a large-scale global scientific project on coral health in a context of climate emergency and accelerating marine biodiversity loss.

The Institute of Evolutionary Biology (IBE), a joint centre of the Spanish National Research Council (CSIC) and Pompeu Fabra University (UPF) in Barcelona, is the only Spanish research centre involved in this international mission. Led by principal investigator Javier del Campo, the IBE (CSIC-UPF) team will contribute to the analysis of the coral microbiome, which is key to understanding coral resilience to climate stress and to anticipating possible future scenarios for tropical reefs.

A race against time to conserve coral reefs

Although they cover only 0.2% of the ocean’s surface, coral reefs host approximately 25% of known marine biodiversity, providing shelter, food and habitat for a wide range of species. Over the past 30–40 years, however, between 30% and 50% of the world’s coral reefs have been lost, mainly due to the climate crisis.

Rising temperatures, ocean acidification and overfishing, among other pressures, cause coral bleaching, a stress process in which corals expel the symbiotic algae that live in their tissues and provide them with colour and nutrients. Without these algae, corals weaken and may eventually die.

Reefs in the Coral Triangle, however, have so far maintained their coral cover. The key to this resistance may lie in the coral microbiome.

“Investigating the resilience factors of these corals may provide new insights for their conservation,” explains Javier del Campo, IBE (CSIC-UPF) researcher participating in the Tara Coral expedition.

In previous studies, the IBE team linked the resistance of Mediterranean corals to thermal stress with the presence of a unicellular microorganism in their microbiome.

“With this expedition we aim to continue studying these holobionts — that is, the community of organisms associated with corals that may influence their survival,” adds del Campo. “Specifically, we will investigate the role of protists in this system.”

A vessel with a long track record in marine ecosystem research

Ten years after the launch of Tara Pacific, the scientific vessel Tara has set sail from its home port of Lorient (France) and will spend 18 months navigating the Coral Triangle. This is the latest expedition of the Fondation Tara Océan. Founded in 2003, the organisation uses high-level scientific expertise and maritime expeditions to advance ocean research and to raise awareness and educate young people and the general public.

Javier del Campo previously took part in a Tara Foundation expedition in 2010. “The Tara Oceans project aimed to sail across the planet to better understand microbial life in the oceans. I sailed the leg from Sharm El-Sheikh, in Egypt, to Djibouti in Africa, with a stop in Jeddah, Saudi Arabia,” explains Javier del Campo, principal investigator of the Microbial Ecology and Evolution Laboratory at IBE. “This leg corresponded to the initial phase of the three-year project and was the first to leave the Mediterranean, where we would refine the techniques that would later be used to sample the rest of the campaign. In my case, I helped set up methods for sampling and preserving planktonic protist samples.”

Understanding in order to value and protect: bringing research on the coral holobiont closer to society

In 2024, del Campo also collaborated with Fondation Tara Océan during the “Traversing European Coastlines” (TREC) expedition, providing the project with advanced equipment to investigate the composition and structure of the coral holobiont. Through this participation, IBE also contributed to outreach and awareness-raising about the critical importance of preserving coastal ecosystems.

The outreach work of del Campo’s team also continues through the current LIPSea-M project, funded by the Fundación Daniel y Nina Carasso. As part of this initiative, the IBE team will collaborate with the UPF CINEMA research group in an art-science project to create an expanded film on the climate crisis.