Recent research has provided direct evidence that deep-dwelling mesopelagic fish, which constitute a substantial portion of global fish biomass, excrete carbonate minerals at rates comparable to their shallow-water counterparts. This discovery validates existing global models that suggest marine fish play a significant role in biogenic carbonate production within the ocean.
Scientists at the University of Miami Rosenstiel School of Marine, Atmospheric, and Earth Science conducted a study on the blackbelly rosefish (*Helicolenus dactylopterus*), a deep-sea species inhabiting depths of 350–430 meters. The researchers found that these fish produce intestinal carbonate, known as ichthyocarbonate, at rates and compositions similar to those of shallower fish species. This finding indicates that depth and pressure do not inhibit ichthyocarbonate formation in mesopelagic fish.
These results strengthen global estimates of fish-derived carbonate production, confirming that mesopelagic fish are substantial contributors to the ocean's carbonate budget. The study also highlights the importance of ichthyocarbonate in the ocean carbon cycle, especially given the vast, underexplored biomass of the mesopelagic zone.
The findings open new avenues for studying deep-sea carbon dynamics and may improve Earth system models, which incorporate interactions between physical, chemical, and biological processes, such as biological carbon production and export. Understanding the role of mesopelagic fish in the carbon cycle is crucial for developing accurate models of ocean chemistry and climate processes.