Most cited article - PubMed ID 36192539
Defending Earth's terrestrial microbiome
Mycorrhizal fungi are ecosystem engineers that sustain plant life and help regulate Earth's biogeochemical cycles1-3. However, in contrast to plants and animals, the global distribution of mycorrhizal fungal biodiversity is largely unknown, which limits our ability to monitor and protect key underground ecosystems4,5. Here we trained machine-learning algorithms on a global dataset of 25,000 geolocated soil samples comprising >2.8 billion fungal DNA sequences. We predicted arbuscular mycorrhizal and ectomycorrhizal fungal richness and rarity across terrestrial ecosystems. On the basis of these predictions, we generated high-resolution, global-scale maps and identified key reservoirs of highly diverse and endemic mycorrhizal communities. Intersecting protected areas with mycorrhizal hotspots indicated that less than 10% of predicted mycorrhizal richness hotspots currently exist in protected areas. Our results describe a largely hidden component of Earth's underground ecosystems and can help identify conservation priorities, set monitoring benchmarks and create specific restoration plans and land-management strategies.
- Publication type
- Journal Article MeSH
The rapid melting of mountain glaciers and the vanishing of their streams is emblematic of climate change1,2. Glacier-fed streams (GFSs) are cold, oligotrophic and unstable ecosystems in which life is dominated by microbial biofilms2,3. However, current knowledge on the GFS microbiome is scarce4,5, precluding an understanding of its response to glacier shrinkage. Here, by leveraging metabarcoding and metagenomics, we provide a comprehensive survey of bacteria in the benthic microbiome across 152 GFSs draining the Earth's major mountain ranges. We find that the GFS bacterial microbiome is taxonomically and functionally distinct from other cryospheric microbiomes. GFS bacteria are diverse, with more than half being specific to a given mountain range, some unique to single GFSs and a few cosmopolitan and abundant. We show how geographic isolation and environmental selection shape their biogeography, which is characterized by distinct compositional patterns between mountain ranges and hemispheres. Phylogenetic analyses furthermore uncovered microdiverse clades resulting from environmental selection, probably promoting functional resilience and contributing to GFS bacterial biodiversity and biogeography. Climate-induced glacier shrinkage puts this unique microbiome at risk. Our study provides a global reference for future climate-change microbiology studies on the vanishing GFS ecosystem.
Forests influence climate and mitigate global change through the storage of carbon in soils. In turn, these complex ecosystems face important challenges, including increases in carbon dioxide, warming, drought and fire, pest outbreaks and nitrogen deposition. The response of forests to these changes is largely mediated by microorganisms, especially fungi and bacteria. The effects of global change differ among boreal, temperate and tropical forests. The future of forests depends mostly on the performance and balance of fungal symbiotic guilds, saprotrophic fungi and bacteria, and fungal plant pathogens. Drought severely weakens forest resilience, as it triggers adverse processes such as pathogen outbreaks and fires that impact the microbial and forest performance for carbon storage and nutrient turnover. Nitrogen deposition also substantially affects forest microbial processes, with a pronounced effect in the temperate zone. Considering plant-microorganism interactions would help predict the future of forests and identify management strategies to increase ecosystem stability and alleviate climate change effects. In this Review, we describe the impact of global change on the forest ecosystem and its microbiome across different climatic zones. We propose potential approaches to control the adverse effects of global change on forest stability, and present future research directions to understand the changes ahead.
