Plants that haven't seen daylight since they were frozen more than 400 years ago during the "Little Ice Age" are sprouting new growth, Canadian scientists say.

The plant life has been coming back to life as glaciers in Canada's high arctic region have been retreating at an accelerated rate since 2004, researchers at the University of Alberta reported.

The retreating glaciers have exposed land -- and the frozen plant life -- that had not seen light of day since a widespread climatic cooling lasting roughly from 1550 to 1850, a period dubbed the Little Ice Age.

The "back-from-the-dead" capability of the plants, known as bryophytes, could provide insights into to how ecosystems recover from the planet's cyclic long periods of ice coverage, the researchers said.

The researchers said they were surprised by an emergence of the bryophytes buried under ice for so long.

"When we looked at them in detail and brought them to the lab, I could see some of the stems actually had new growth of green lateral branches, and that said to me that these guys are regenerating in the field, and that blew my mind," study lead author Catherine La Farge told BBC News.

The retreating ice is uncovering an array of life including cyanobacteria and green terrestrial algae, she said, and many of the species being revealed are entirely new to science.

"It's a whole world of what's coming out from underneath the glaciers that really needs to be studied," she said.