A new study reveals that bacteria living inside marine fish play a key role in producing calcium carbonate, influencing ocean health and carbon storage. The findings challenge previous assumptions that fish alone handled this process. Researchers from the University of Miami led the work published in PLOS Biology.
Scientists found that gut microbes in bony fish, known as teleosts, work with their hosts to form solid calcium carbonate pellets called ichthyocarbonates. These minerals help regulate ocean chemistry as fish drink seawater to stay hydrated. Experiments with Gulf toadfish showed higher production in saltier water conditions.