New bacteria in coral reefs could yield useful molecules ^{CEFR B2}

Between 2016 and 2018 the Tara Pacific expedition carried out a broad survey of Pacific coral reefs, sampling 32 archipelagos and collecting 58,000 samples to map reef biodiversity and nearby open water systems. The project aimed to explore the largely unknown microbial life that lives in and around corals.

Using a genomic approach, Rebecca Vega Thurber and colleagues reconstructed more than 13,000 metagenome-assembled microbial genomes from reef-building corals. Ninety percent of what they found had never been recorded before; Thurber noted, "That’s a total of 3,700 new bacteria we discovered through this approach." Nearly all of these bacteria were specific to their coral hosts and were not present in the surrounding seawater.

These microbes produce bioactive metabolites — small molecules bacteria use to grow, communicate, defend themselves and adapt. The researchers highlight potential applications in medicine and industry, including drugs, laundry detergents, concrete development and new biotechnology materials. They also identified new groups of Acidobacteriota with previously unknown enzymatic capabilities, a finding that could be valuable for protein engineering. The study found that the biosynthetic potential of coral microbiomes rivalled or even surpassed that of sponges, a well-known source of bioactive compounds.

The study sampled only three coral species out of hundreds, so more species could reveal further diversity. The authors warned that these molecular resources exist in fragile ecosystems threatened by ocean warming and bleaching, and they stressed the importance of conserving coral reefs as vital reservoirs of molecular diversity.