Marine Biofilm Metagenomes Reveal How Bacterial Genes Control Coral Larval

Marine biofilms may be a key driver of coral larval settlement, but the bacterial signals behind induction or inhibition were unclear. A study in Environmental Microbiome analyzed metagenomes from marine biofilms to identify bacterial genetic pathways linked to larval settlement across four broadcast-spawning non-acroporid coral species: Platygyra sinensis, Dipsastrea favus, Echinophyllia aspera, and Porites lobata. Settlement was defined as larval attachment followed by metamorphosis. The researchers used biofilms formed during the 2021 Great Barrier Reef mass spawning event on concrete settlement tabs measuring 14 by 14 millimeters, across twelve combinations, to connect bacterial community identities with their functional genetic potential. The work builds on limitations of earlier approaches, including 16S amplicon profiling and isolate-based tests, and aims to support reef restoration efforts where these corals are difficult to rear.