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The world’s oldest moss, called Takakia, has persisted in some of Earth’s most extreme environments for millions of years. And despite the fact that this ancient plant is one of the fastest-evolving species of moss known to science, it may not survive the climate crisis.
A team of researchers spent a decade studying the 390 million-year-old moss that grows on the icy, isolated cliffs of the Tibetan Plateau.
Called the “roof of the world,” this remote area surrounded by the Himalayas is the world’s highest and largest plateau. The tiny, slow-growing moss can also be found in parts of Japan and the United States.
The researchers went on 18 expeditions between 2010 and 2021 to understand how Takakia has adapted to survive for millions of years in its home, located 13,123 feet (4,000 meters) above the ground. A study detailing the findings was published Wednesday in the journal Cell.
“We set out to describe and analyze a living fossil,” said study coauthor Dr. Ralf Reski in a statement. He is a plant biotechnologist and professor in the faculty of biology at the University of Freiburg in Germany.
The crucial role of early plants
As animal life began in Earth’s oceans around 500 million years ago, plant life that evolved from freshwater algae began to cover the planet’s rocky land masses and adapted to live in harsher terrestrial environments, according to the study authors. The tiny plants caused a huge shift in Earth’s atmosphere as they eroded the rocks they grew on and converted light energy into chemical energy through photosynthesis. As the plants broke down stone, this biological weathering released minerals, and the photosynthetic process resulted in organic compounds and oxygen.
The plants made Earth’s landmasses?more hospitable to animal life, which began to evolve and become more complex over time.
When the Indian and Eurasian tectonic plates collided 65 million years ago, the cataclysmic event created the Himalayas. Takakia, already about 100 million years old at the time, rose right along with the Himalayas and was forced to quickly adapt to the much harsher environment.
“In the Himalayas, you can experience four seasons within a day,” said lead study author Ruoyang Hu, plant biologist and co-expedition leader at Capital Normal University in China, in a statement. “At the foot of the mountain, it is sunny and clear. When you get to the halfway point, there is always a light rain — it feels like you’re walking in a cloud. And when you get to the top, it snows and it’s very cold.”
The secrets of plant DNA
The research team collected samples to sequence Takakia’s DNA for the first time and determine how the climate crisis is affecting the plant. Given how ancient the plant is, the team also wanted to determine whether Takakia was really a moss or another type of ancient plant, such as liverwort or algae. The study research showed that Takakia is indeed a moss.
“The idea was to go as deep as possible into the history of the first land plants to see what they can tell us about evolution,” Reski said. “We found that Takakia is currently the genome with the highest number of fast-evolving genes. It’s very active on the genetic level.”
Takakia’s genome has evolved over time, adapting to recover from ultraviolet damage and make alterations and fixes to broken DNA, the researchers said. But the plant’s actual form has changed very little, despite the fact that its genetics are always changing. The moss has also adapted to grow in different locations by branching.
“Takakia plants are covered with heavy snow for eight months each year, and then are subjected to high-intensity ultraviolet radiation during the 4-month light period,” said study coauthor Yikun He, plant biologist at Capital Normal University, in a statement. “As a result, this continuous branching forms a network structure and a very sturdy population structure, which can effectively resist the invasion of heavy snowstorms.”
The research team also studied the plants using time-lapse cameras and satellite weather data to track larger changes in the moss’ environment. As the local temperature average increased each year, the population of Takakia moss decreased by 1.6% annually, the study authors noted.
As the planet warms, the plateau’s glaciers are rapidly melting. The moss is also experiencing higher levels of UV radiation that is capable of killing plants adapted to harsh environments.
Takakia’s uncertain future
During the decade-long study, the moss became harder to find.
“Our prediction shows that suitable conditions (and) regions for Takakia will shrink to only around 1,000 -1,500 square kilometers all over the world at the end of the 21st century,” Hu said.
The study authors don’t think the moss is likely to survive another 100 years and could face extinction, despite its millions of years of evolution and resilience.
“As a sensitive environmental indicator species, its observed decline over the past decade is an early warning signal of the grave danger of global warming,” the authors wrote in the study.
The research team wants to protect the moss by cultivating it in labs and transplanting it to new areas.
“Plant scientists cannot sit idly by. We are attempting to multiply some plants in the laboratory and then transplant them to our experimental sites in Tibet,” Yikun He said. “After five years of continuous observation, it has been found that some transplanted plants can survive and thrive, which may be the dawn of the recovery — or at least a postponement of extinction — of Takakia populations.”
The study authors hope that the study of rare, tiny species like Takakia can serve as a larger wake-up call about the climate crisis. “But the dinosaurs came and went, and so might humans, if we are not careful with our planet. Takakia may die because of climate change, but the other mosses will survive, even if we humans cannot.
“We humans like to think that we are on top of evolution,” Reski said. “But the dinosaurs came and went, and so might humans, if we are not careful with our planet. Takakia may die because of climate change, but the other mosses will survive, even if we humans cannot. You can learn a lot from the simplest plants about the history of this planet, and maybe the future.”