Key role of moss in supplementing nitrogen for plant growth under warming in a permafrost ecosystem.
Zhou W, Bai Y, Xie Y, Wei B, Wanek W
Climate Adaptation
It shows that the humble mosses you see blanketing forest floors and tundra are quietly working as nitrogen factories, and without them, the plants around them — and the entire ecosystem — could struggle to survive a warming world.
As the climate warms, plants in cold, frozen-ground regions grow bigger and faster, which means they need more nitrogen — a key nutrient — from the soil. Scientists tested many different ways the soil supplies nitrogen and found that only one kept up with the plants' growing appetite: tiny bacteria living inside mosses that can pull nitrogen straight out of the air. Warming caused changes in the mosses themselves that gave these bacteria more room and food to do their job.
Key Findings
After 2 years of experimental warming on the Tibetan Plateau, plant nitrogen demand significantly increased while leaf nitrogen resorption did not change, meaning plants needed more external nitrogen input.
Of 43 measured nitrogen supply and demand variables, moss-associated biological nitrogen fixation was the only process that responded positively to warming.
Warming altered moss functional traits in ways that likely expanded colonization niches for nitrogen-fixing bacteria (diazotrophs) and increased carbon availability to fuel their activity.
chevron_right Technical Summary
When permafrost ecosystems warm up, plants grow faster and need more nitrogen — but the only nitrogen source that keeps up with this demand is fixation by microbes living in mosses. This finding reveals mosses as a critical, underappreciated player in how cold ecosystems respond to climate change.
Abstract Preview
Enhanced plant productivity under climate warming may partially offset soil carbon losses in cold ecosystems, but this compensation depends on whether soil nitrogen (N) supply can keep pace with th...
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