Geml József, Morgado Luis N, Semenova-Nelsen Tatiana A
MTA-EKE Lendület Environmental Microbiome Research Group, Eszterházy Károly University, Eger, Hungary.
Naturalis Biodiversity Center, Leiden, Netherlands.
Front Microbiol. 2021 Mar 12;12:628746. doi: 10.3389/fmicb.2021.628746. eCollection 2021.
The arctic tundra is undergoing climate-driven changes and there are serious concerns related to the future of arctic biodiversity and altered ecological processes under possible climate change scenarios. Arctic land surface temperatures and precipitation are predicted to increase further, likely causing major transformation in terrestrial ecosystems. As a response to increasing temperatures, shifts in vegetation and soil fungal communities have already been observed. Little is known, however, how long-term experimental warming coupled with increased snow depth influence the trajectories of soil fungal communities in different tundra types. We compared edaphic variables and fungal community composition in experimental plots simulating the expected increase in summer warming and winter snow depth, based on DNA metabarcoding data. Fungal communities in the sampled dry and moist acidic tundra communities differed greatly, with tundra type explaining ca. one-third of compositional variation. Furthermore, dry and moist tundra appear to have different trajectories in response to climate change. Specifically, while both warming and increased snow depth had significant effects on fungal community composition and edaphic variables in dry tundra, the effect of increased snow was greater. However, in moist tundra, fungal communities mainly were affected by summer warming, while increased snow depth had a smaller effect and only on some functional groups. In dry tundra, microorganisms generally are limited by moisture in the summer and extremely low temperatures in winter, which is in agreement with the stronger effect of increased snow depth relative to warming. On the contrary, moist tundra soils generally are saturated with water, remain cold year-round and show relatively small seasonal fluctuations in temperature. The greater observed effect of warming on fungi in moist tundra may be explained by the narrower temperature optimum compared to those in dry tundra.
北极苔原正在经历由气候驱动的变化，人们严重关切北极生物多样性的未来以及在可能的气候变化情景下生态过程的改变。预计北极陆地表面温度和降水量将进一步上升，这可能导致陆地生态系统发生重大转变。作为对气温上升的响应，已经观察到植被和土壤真菌群落的变化。然而，对于长期实验性变暖以及积雪深度增加如何影响不同苔原类型土壤真菌群落的发展轨迹，人们了解甚少。基于DNA宏条形码数据，我们比较了模拟夏季变暖和冬季积雪深度预期增加的实验地块中的土壤变量和真菌群落组成。在采样的干旱和湿润酸性苔原群落中，真菌群落差异很大，苔原类型解释了约三分之一的组成变化。此外，干旱和湿润苔原在应对气候变化时似乎有不同的发展轨迹。具体而言，虽然变暖和积雪深度增加对干旱苔原的真菌群落组成和土壤变量都有显著影响，但积雪增加的影响更大。然而，在湿润苔原中，真菌群落主要受夏季变暖的影响，而积雪深度增加的影响较小，且只对某些功能组有影响。在干旱苔原中，微生物通常在夏季受水分限制，在冬季受极低温度限制，这与积雪深度增加相对于变暖的更强影响一致。相反，湿润苔原土壤通常充满水分，全年保持低温，温度的季节性波动相对较小。在湿润苔原中观察到的变暖对真菌的更大影响可能是由于其温度最适范围比干旱苔原更窄。
