The functional diversity of stream microbes on mountainsides across Eurasia based on Geochip 4.0

Understanding the biogeographical patterns and underlying drivers of microbial functional diversity is essential for anticipating climate change impacts on ecosystem functioning worldwide. However, this matter remains scarcely addressed in freshwater ecosystems. Using the high-throughput gene array GeoChip 4.0, we show that functional gene alpha diversity and compositon differ across mountains, alpha diversity declines towards high elevations and compositional turnover increases with larger elevational distances. Both continental- and mountain-scale patterns were primarily driven by climatic variables. Fifty two biofilm samples along mountainsides were collected from one stream in Balggesvarri (Norway, 17 samples), one stream in Pyrenees (Spain, 17 samples) and one stream in Laojun (China, 18 samples), spanning an altitudinal range of 18-771 masl, 850-2500 masl and 1828-4045 masl, respectively