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Journalism of Courage
Takakia is a rare genus of moss that adapted over millions of years to life at high altitudes. An international group of scientists have discovered exactly how it developed the ability to survive frost, life-threatening UV radiation and other hazardous conditions. While doing so, they found that the habitat of this species has been greatly altered by climate change in just a few years.
When seen from a distance, Takakia looks like a later of moss or green algae on the rocks where it grows. But closer inspection would reveal slender turf around one centimetre in length with an arrangement of short, finger-like leaves.
Takakia is a genus that only has two species. And both of them are found together only in one place—the Tibetan Plateau. In an article published in the peer-reviewed journal Cell, researchers describe the genetic traits that protect this moss from its harsh environment.
The species on the Tibetan Plateau are covered by heavy layers of snow for eight months of the year. They are then exposed to unusually high levels of UV radiation for the other four months. Takakia evolved traits to survive these conditions over the last 65 million years. The plateau is only about that old, having been uplifted by continental drift. Gradually, over millenia, the moss’s habitat got increasingly more extreme.
“These geological time records help us to trace the gradual adaptation to a life at high altitudes in the Takakia genome. Although the Takakia genome is evolving so rapidly, the morphology has not changed recognisably for more than 165 million years. This makes Takakia a true living fossil. This apparent contrast between unchanged shape and rapidly changing genome is a scientific challenge for evolutionary biologists,” said Ralf Reski, co-author of the article, in a press statement.
The moss is of considerable interest to researchers, according to the University of Freiburg, where Reski works. This is because it combines features found in mosses, liverworts and green algae. According to co-author Yikun He of the Capital Normal University in China, the study was able to prove that Takakia is a moss that separated from other mosses 390 million years ago, not long after the first land plants evolved.
The plants took millions of years to adapt to decreasing temperatures and increasing radiation but now, its habitat is now changing in just decades because of climate change. Since scientists began taking measurements in 2010, they gound an average temperature increase of almost half a degree Celsius per year there. At the same time, the glacier near the sample sites receded by nearly 50 metres per year.
These hardy species don’t seem to cope as well temperature rise compared to others. Their populations become significantly smaller over the study period while other plants benefited from the warming. The researchers believe this trend will continue. A species that saw the dinosaurs come and go might not survive the coming of humans.
