Bacteria help form clouds

Small organisms are really everywhere: bacteria, fungal spores and biological debris are found both in clouds and seem to help the cloud droplet formation - scientists have discovered .

Studying the role of these organisms in the process of cloud formation can help determine the greatest mystery in the predictions of climate change - how clouds affect the climate.

Scientists have long known that microorganisms or parts of their bodies can be swept up into the air and travel over long distances. For example, the leaves fall to the ground, gradually dry and crumble, and then wind away. The same thing happens with pollen and even bacteria. Scientists have not yet experimented, so they do not know whether these high bacteria are still alive.

Meanwhile, in-room experiments show that these particles (along with dust and tiny particles suspended in the air) can act as ice nuclei, the main part in the clouds. Around these nuclei, water and ice in the atmosphere stop and grow, creating clouds and eventually leading to rain.

'Understand which elements form ice elements (which exist at very low density and are very difficult to measure) also means that you will better understand the processes that lead to rain,' Kim Prather, The research team member of Scripps Oceanographic Research Institute in San Diego, Calif., said.

Scene seen from the plane when scientists sample the cloud. According to calculations, biological elements such as bacteria, pollen, fungi, act as nuclei during ice formation in clouds. (Photo: NCAR)

While most scientists accept that biological elements form clouds, it is much more difficult to observe the actual process.

'This is really too difficult a measurement for us,' Prather said.

Prather and her colleagues put a spectrometer on to find out in what factors a cloud has. They put the device on a helicopter and flew through the clouds in the sky of Wyoming in the autumn of 2007. This effort helped them for the first time detect biological elements present in the clouds.

They came to the conclusion that biological elements account for one-third of the inorganic and ice-forming particles account for 50%.

But specifically what this biological component is, researchers cannot answer.

'With the technique currently in use, we can only say that it is a biological element,' said Karri Pratt, a graduate student at the University of California in San Diego.

The team was able to use air samples and the chemical composition of dust to find the origin of biological elements, which are suspected to be from Asia or Africa.

The findings, published in the online journal Nature Geoscience on May 17, suggest that bacteria and other biological elements are swept up high in dust storms and travel very far, to the spot they contribute to cloud formation.

The results of this study can be used to determine which climate models show the effect of climate clouds on the climate - models cooled by light radiation again, heated by heat traps, or rather change the rule of the rain.

'If we understand the origin of the particles that make up clouds and their relative density, we can determine the effect of these sources on climate,' Prather said.

The research is funded by the National Institute of Science and the National Center for Climate Research.