Plankton Cool Off With Own Clouds:
Pretty damn cool I think.Phytoplankton may be small, but that doesn't mean they can't do big things -- like change the weather to suit their needs.
A recent study funded by NASA's Earth Science Department shows that the tiny sea plants release high quantities of cloud-forming compounds on days when the sun's harmful ultraviolet rays are especially strong. The compounds evaporate into the air through a series of chemical processes that result in especially reflective clouds. This, in turn, blocks the radiation from bothering the phytoplankton.
The findings not only confirm earlier theories that plankton are linked to the creation of clouds above the ocean but could also lead to a better understanding of how living things affect the Earth's climate.
"The take-home message is that all the processes that are going on in the ocean and the climate are very tightly connected," said David Siegel, co-author of the study and director of the Institute for Computational Earth System Science in Santa Barbara, California. "This is really the impetus for other researchers to look into the whole cycle of how biology and climate interact."
Siegel and Woods Hole Oceanographic Institution researcher Dierdre Toole announced the results of their study in the May issue of the Geophysical Research Letters, a scientific journal.
The two researchers performed the study on measurements taken off the coast of Bermuda. There, they found that the ocean levels of a compound called dimethylsulfoniopropionate, or DMSP, were directly related to the level of ultraviolet radiation reaching the phytoplankton that live near the ocean's surface.
DMSP is an important link in the plankton-to-cloud cycle because, as it leaves the phytoplankton cells and enters into the water, bacteria break it down into a chemical called dimethylsulfide, or DMS. Evaporated water, in turn, carries the DMS into the air where the chemical reacts with oxygen to form various sulfur compounds. These compounds collect as dust particles that promote water condensation, which, finally, leads to cloud formation.
The entire process takes place very rapidly, ensuring that the plankton aren't under the sun's rays too long. In their study, Siegel and Toole found that the upper layer of DMS in the atmosphere could be replaced in just a few days.
That the process happens at all may be a sign that the Earth is better prepared to handle climate forces like the depletion of the ozone layer, which also blocks ultraviolet light, than previously thought. However, Siegel believes it's too early to make such assessments because it's unclear just how widespread the phenomenon is. It's also unclear just how much ultraviolet light and other forces the system can tolerate.
The researchers now plan to create computer models that explore how the presence and absence of phytoplankton might change the climate. They also hope to add to their study by using information from NASA's Sea-viewing Wide Field-of-view Sensor mission, which collects data on shifts in visible light reaching the ocean's surface.
It's possible that the extended work will show that phytoplankton do affect climate on a global scale, said Siegel.
If that's the case, it's also possible that scientists who like to talk about the "butterfly effect" -- the theory that the flapping of a butterfly's wings in one part of the world could eventually lead to violent weather patterns in another -- may soon find that it's more hip to talk about the "phytoplankton effect."