Skip to main content
Cloud formation above mountain range

Microbiologist pierces riddle of why clouds form

By Tim Radford

Cloud formations and the science behind them

Distinguished Professor of Microbiology Stephen Giovannoni is the lead author of a new study in the journal Nature Microbiology that reveals how a certain class of microbes can regulate atmospheric temperatures and help in the formation of clouds over the world's oceans.

These vital cogs in the planetary machine are astonishingly prevalent and utterly invisible and they traffic in potent chemicals on an unbelievable scale. They make the dimethyl sulphide molecules that waft skywards to provide nuclei around which cloud droplets form.

When the sun shines brightly they get to work, and the gas they produce then makes aerosols that seed clouds which reflect sunlight and damp down the planetary temperatures again.

What the research team, led by Steve Giovannoni, and others has established is the evolutionary box of tricks that makes planetary chemistry on such a prodigious scale possible.

Marine phytoplankton make a compound called dimethyl-sulfoproprionate or DMSP. They make it on a massive scale: an estimated 10 billion metric tons of the stuff each year.

When the skies are clear, the tiny microbial plants flourish to photosynthesize even more of the compound. And then an important group of Pelagibacterales microbes moves in to take the chemical and cleave it, to release two gases.

This work is part of the North Atlantic Aerosols and Marine Ecosystem Study, funded by NASA, and other agencies. Collaborators were from OSU, the University of East Anglia in the United Kingdom, Louisiana State University, the Plymouth Marine Laboratory in the United Kingdom, the Qingdao Aquarium in China, and the Pacific Northwest National Laboratory.

Read the complete article at Climate News Network, Eureka Alert, or on OSU's website.