A new study suggests bacteria in the intestines of bony fish, known as teleosts, work with their hosts to produce calcium carbonate. This mineral is important for ocean chemistry and acts as a significant carbon sink. The fish constantly drink seawater, and their intestines remove excess calcium and carbonate ions, with gut bacteria playing a key role in the process. This finding adds a new biological pathway to our understanding of marine carbon cycles. The calcium carbonate produced by fish can lock away carbon for long periods, potentially influencing how we model ocean carbon storage. Researchers are still working out the full scale of this contribution compared to other marine carbon sinks like phytoplankton or coral reefs. For those tracking natural carbon removal mechanisms, this study highlights an overlooked player in ocean chemistry. The research was conducted at the Rosenstiel School of Marine and published through multiple news outlets. It underscores how even small biological processes can have outsized effects on global carbon cycles.
