Scientists at the Pennsylvania State University (PSU) have found two new species of bacteria which have been buried beneath two miles of ice in Greenland for at least 120,000 years.

Prof. Jennifer Loveland-Curtze led the discovery of the harmless bacteria named Herminiimonas glaciei and Chryseobacterium greenlandensis, the study of which are published in Monday's issue of the International Journal of Systematic and Evolutionary Microbiology.

The state of the H. glaciei and C. greenandensis were unknown when they were found, though it was possible they were slowly metabolizing and reproducing, according to the PSU researchers. Retrieved samples of the purple-brown H. glaciei later grew into colonies after these were incubated at 36 degrees Fahrenheit for seven months and at 41 degrees F in the succeeding four months, the study said.

The scientists believe the bacteria survived because of its very small size; both are 10 to 50 times smaller than the E. coli bacteria. Such size enabled it to hide from predators and, thus, survive.

"The exceptionally low temperatures can preserve cells and nucleic acids for even millions of years," LiveScience quoted Loveland-Curtze as saying.