sentences:  He says that it is very probable that the samples are heavily contaminated with tissue and microbes from the outside world.The contamination possibility has been refuted by Scott Rogers, because the control measures were rigorous, and the combinations of organisms found in each of the ice samples were consistent with organisms living in a cold lake and ice (including a sequence from an Antarctic rock cod), and were inconsistent with contamination introduced while sampling or from the lab procedures.Also, all of the lab procedures were performed in parallel with ice samples from Lake Erie, and the two resulting data sets were completely different.