According to a study published in the journal Proceedings of the National Academy of Sciences, a large number of bacteria have been spotted in the middle and upper troposphere. The study, which is one of its kind, is supported by NASA as well as by the National Science Foundation.

Study researchers used genomic techniques to know the presence of living microorganisms. For now, it is not known that from where the living microorganisms have come from at troposphere. There are several options from where bacteria can get to the troposphere.

There are chances that it might be regular for bacteria to be present at troposphere. It is also possible that the bacteria have lofted from the Earth's surface to troposphere. Great interest has now been developed in the project, said researchers.

They were of the view that the presence of living bacteria can lead to the development of ice formation. Formation of ice can have huge impact on climate, Kostas Konstantinidis, an assistant professor at the Georgia Institute of Technology.

"In the absence of dust or other materials that could provide a good nucleus for ice formation, just having a small number of these microorganisms around could facilitate", said Nenes.