Across the world’s oceans, the average long-term temperature shift associated with ocean warming has been estimated at just over 20 kilometers, about 13 miles, per decade. By comparison, marine heatwaves have displaced temperatures an average of approximately 200 kilometers, roughly 120 miles, in a matter of months. In effect, marine heatwaves are shifting ocean temperatures at similar scales to what is anticipated with climate change — but in much shorter time frames. Click here to read more.

To measure the temporary dislocation of ocean surface temperatures, which can in turn drive ecological changes, NOAA scientists have introduced a new metric called “thermal displacement.” To read the research paper describing the changes and the means of measuring them Click here.

Another study published by researchers at the University of Adelaide recreated a marine habitat in a series of 1,800-litre tanks and then subjected some to temperature and CO₂ changes. The research showed that ocean heating “reshuffles species communities” with weedy plants and algae thriving but the “abundance of other species, especially invertebrates, collapses”.

Prof Ivan Nagelkerken, of the University of Adelaide’s Environment Institute and who led the research, said gazing into the tanks after six months when the study period ended had not been a pretty sight. After being subjected to higher temperatures and higher CO₂ the rocks, he said, were overgrown with turf algae and the sandy bottom had a lot more slimy algae that is toxic to some species. He said the changed pyramid that was fatter at the bottom and thinner in the middle, could eventually see larger predators also losing out. Click here.

In the study, the researchers write: “The top of food webs may eventually become depleted under future climate conditions or additional human disturbances.” Click here to read the full paper.