Bacteria may contribute more to climate change as planet heats up

As bacteria adapt to hotter temperatures, they speed up their respiration rate and release more carbon, potentially accelerating climate change.

By releasing more carbon as global temperatures rise, bacteria and related organisms called archaea could increase climate warming at a faster rate than current models suggest. The new research, published today in Nature Communications by scientists from Imperial College London, could help inform more accurate models of future climate warming.

Bacteria and archaea, collectively known as prokaryotes, are present on every continent and make up around half of global biomass – the total weight of all organisms on Earth.

Most prokaryotes perform respiration that uses energy and releases carbon dioxide – just like we do when we breathe out. The amount of carbon dioxide released during a given time period depends on the prokaryote’s respiration rate, which can change in response to temperature.

However, the exact relationship between temperature, respiration rate and carbon output has been uncertain. Now, by bringing together a database of respiration rate changes according to temperature from 482 prokaryotes, researchers have found the majority will increase their carbon output in response to higher temperatures to a greater degree than previously thought.

Lead researcher Dr Samraat Pawar, from the Department of Life Sciences at Imperial, said: “Rising temperatures therefore cause a ‘double whammy’ effect on many prokaryote communities, allowing them to function more efficiently in both the short and long term, and creating an even larger contribution to global carbon and resulting temperatures.”

The researchers compiled prokaryote responses to temperature changes from across the world and in all different conditions – from salty Antarctic lakes below 0°C to thermal pools above 120°C. The short-term responses of medium-temperature prokaryotes to warming were larger than those reported for eukaryotes – organisms with more complex cells, including all plants, fungi and animals.

Lead author of the new research, PhD student Thomas Smith from the Department of Life Sciences, said: “Most climate models assume that all organisms’ respiration rates respond to temperature in the same way, but our study shows that bacteria and archaea are likely to depart from the ‘global average’.

A lake tinged pink by salt-loving halobacteria

Original publish by Imperial with slightly modification