Large-scale evidence for highly coupled soil multi-elements in permafrost ecosystems.

The coupled soil element cycles are the foundation of many crucial ecosystem functions such as primary production and climate regulation. However, whether and how multiple soil elements are coupled in permafrost regions remains unclear. Here, we collected and analyzed 240 soil samples from the active layer (0-10 cm) and permafrost deposits (top 50 cm) at 24 sites along a 1000-km transect on the Tibetan Plateau. We found that a high degree of soil element coupling, defined as the mean Spearman rank correlation among 19 measured elements, was maintained in the two soil layers. Nutrient elements were more likely to be coupled than non-nutrient elements, with 19 and 11 sites revealing robust coupling of nutrient and non-nutrient elements, respectively. Furthermore, atomic properties, including atomic mass and electronegativity, affected element coupling in the active layer, but had no effect in the permafrost deposits. These findings advance our understanding of terrestrial biogeochemistry in permafrost regions and inspire further research to explore the linkage of soil element coupling with ecosystem functioning.