Joint corresponding author, Dr. Rod Wilson, a fish biologist at the University of Exeter, said: "An obvious area of future study in this field relates to the geological record and in particular to the role of this process in periods of the Earth's history when ocean chemistry was very different and temperatures considerably warmer. For example, a preliminary study has estimated fish carbonate production under Cretaceous seawater conditions, the time (146-65 million years ago) when large masses of chalk were deposited (famously including the White Cliffs of Dover). These studies, although in their early stages, suggest massive increases in production of this carbonate by fish during this ancient time. Perhaps fish have been a major contributor to these iconic carbonate deposits, in addition to the better known micro-fossils of shelled organisms? However, we are yet to look for direct evidence of this unusual contribution of fish, and we are currently seeking research funds to help answer this intriguing question."
And what about the future? The study finds clear evidence that at present such carbonates can accumulate within the marine environment, at least in warm shallow seas, but the fate of this carbonate under changing oceanographic conditions (especially marine chemistry change) is unclear.
On the one hand, rising sea-surface temperatures should result in higher rates of carbonate production by fish since production increases markedly with temperature. On the other hand, increasing ocean acidity may mean more of this carbonate is dissolved, with potential knock-on effects for ocean carbon cycling and absorption of CO2 from the atmosphere.
|Contact: Daniel Williams|
University of Exeter