Ocean acidification may slow the pace of tropicalization of temperate fish communities

Tropical fish could flounder in acidifying oceans

30 September 2021

Carbon emissions could make cool waters unwelcoming for tropical fish escaping rising sea temperatures.

As the oceans warm, tropical fish and other heat-seeking sea life can expand their habitats into temperate waters, a process known as tropicalization. Ocean acidification also affects marine ecosystems, but how the two effects interact is unclear.

Now, a team led by researchers from Adelaide University has compared the numbers of warm-adapted sea urchins and tropical fishes living in temperate tropicalization hotspots and around volcanic vents that emit carbon dioxide, to replicate ocean acidification.

In temperate waters, sea urchins transform kelp forests that support temperate fish species into barren habitats that attract various tropical fish. However, in acidified waters, sea urchin populations plummeted by 87%, turf algae took over from barren habitats, and tropical fish diversity dropped.

Understanding the combined effect of warming and acidification on tropical and temperate fish could reveal whether marine ecosystem structures will be able to adjust to climate change.

Supported content

References

1. Nature Climate Change 11, 249–256 (2021). doi: 10.1038/s41558-020-00980-w