https://www.metoffice.gov.uk/research/climate/cryosphere-oceans/biogeochemistry
The biochemical processes of calcium carbonate production by fish (in ‘The Significance and Management of Natural Carbon Stores in the Open Ocean’):
“The quantitative significance of fish within the inorganic carbon cycle has only recently been highlighted (and may be even larger). In addition, their carbonates appear to have a very different dissolution potential relative to most other calcifiers, with significance for the chemistry of the surface ocean and its ability to absorb atmospheric CO2 . This suggests that we currently do not fully understand this half of the ocean’s carbon cycling and cannot appreciate it properly without substantially more basic information on the role and fate of fish carbonates.”
Lizzie Coldrick 