Canadian researchers from the University of Alberta were exploring the area around Teardrop Glacier in the Canadian Arctic when they found plants that had been frozen for over 400 years during the period known as the Little Ice Age (1550-1850). After bringing them back to their lab, they were about to resurrect some of those mosses and other simple plants.
In a study recently published, they look at the hypothesis that retreating glaciers could expose some of these and bring them back to life, potentially reintroducing some species to ecosystems.
Regeneration of subglacial bryophytes broadens the concept of Ice Age refugia, traditionally confined to survival of land plants to sites above and beyond glacier margins. Our results emphasize the unrecognized resilience of bryophytes, which are commonly overlooked vis-a-vis their contribution to the establishment, colonization, and maintenance of polar terrestrial ecosystems. (source)
This makes me curious whether we could find ways to look under/inside older glacier and revive species that might have disappear for millennia. This could be another way to learn more about past ecosystems.