Phytoplankton and Clouds (& Global Warming)

If you combine this with the story about people vacuuming up Krill as well as the report explaining less Krill in the the Northern Pacific due to climate conditions - it seems that what you end up with is some kind of loop. Like less krill = fewer clouds = warmer temperatures = less krill, etc. (Also less ocean animals, sea gulls, etc.)

Researchers Link Ocean Organisms With Increased Cloud Cover And Potential Climate Change

Atmospheric scientists have reported a new and potentially important mechanism by which chemical emissions from ocean phytoplankton may influence the formation of clouds that reflect sunlight away from our planet.

...Based on satellite data, the researchers hypothesized that airborne particles produced by oxidation of the chemical isoprene -- which is emitted by the phytoplankton -- may have contributed to a doubling of cloud droplet concentrations seen over a large area of ocean off the eastern coast of South America.

Using complex numerical models, they estimated that the resulting increase in cloudiness reduced the absorption of sunlight by an amount comparable to what has been measured in highly polluted areas of the globe....Many environmental scientists believe that increased cloud cover may be partially countering the effects of global warming by reducing the amount of energy the planet absorbs from the sun....

The researchers stumbled upon the phytoplankton-cloud connection quite accidentally. "While looking at the satellite pictures, I noticed that cloud properties over large phytoplankton blooms were significantly different from those that occurred away from the blooms," recalled Meskhidze, now an assistant professor in NC State's College of Physical and Mathematical Sciences.

The Southern Ocean normally has relatively few particles around which cloud droplets can form. The isoprene mechanism could therefore have a significant effect on the development of clouds there -- and may account for most of variation in the area's cloud cover.

"If a lot of particles form because of isoprene oxidation, you suddenly have a lot more droplets in clouds, which tends to make them brighter," Nenes explained. "In addition to becoming brighter, the clouds can also have less frequent precipitation, so you might have a build-up of clouds. Overall, this makes the atmosphere cloudier and reflects more sunlight back into space."
In their paper, the researchers estimated that the isoprene emissions reduced energy absorption in the area by about 15 watts per square meter. "This is a huge signal," said Nenes. "You would normally expect to see a change of a couple of watts."

The Southern Ocean is ideal for study because it is largely untouched by pollution and has relatively steady temperature and meteorological conditions during the seasons in which phytoplankton blooms appear. "This seems to be one of those rare regions in the globe where the biology really takes over," Nenes explained. "That allows us to see strongly the impact of biology on the clouds." (snip)

"It shows that there is still a lot we need to explore to better understand the delicate balance in nature," said Meskhidze. "It will require the cooperative efforts of researchers from many different fields to identify the chemical components in these aerosols, to estimate the amounts of this and other potentially important gases emitted from the ocean, and to better characterize the effort of organics on cloud droplet formation."