Untangling the dry limit for microbial life in rock-inhabiting communities of US Western drylands

Project Information

DRYLIFE

Grant agreement ID: 101062840

DOI

10.3030/101062840

Project closed

EC signature date 10 May 2022

Start date 1 October 2022

End date 30 September 2025

Funded under

• Marie Skłodowska-Curie Actions (MSCA)

Total cost

No data

EU contribution

€ 265 099,20

Coordinated by

UNIVERSITA DEGLI STUDI DELLA TUSCIA
Italy

Periodic Reporting for period 2 - DRYLIFE (Untangling the dry limit for microbial life in rock-inhabiting communities of US Western drylands)

Reporting period: 2024-10-01 to 2025-09-30

Summary of the context and overall objectives of the project

Drylands cover 46% of Earth's surface and support 40% of the global population. These vast regions are highly sensitive to climate change, with projections suggesting they could expand to 56% of the planet by 2100 due to increasing aridity. This shift threatens to severely impact biodiversity and the functioning of ecosystems—especially in areas transitioning from semi-arid to hyper-arid conditions. In the harshest environments, such as hyper-arid regions, microscopic life plays an essential role. Among these, endolithic microbes—organisms that live inside rocks—stand out for their extraordinary ability to survive and adapt under extreme stress.
Four main objectives are assessed in this research:
1. Exploring the diversity of microbial communities along aridity gradients, from relatively mild drylands to the most extreme deserts. This helps expand our knowledge of microbial life, reveals new species, and offers clues about how microbial communities are distributed across different regions of the planet.
2. Investigating the genetic traits that allow rock-dwelling microbes to resist intense stress. By uncovering how these organisms cope with drought, extreme temperatures, and intense solar radiation, we gain a clearer picture of how life adapts to the planet’s harshest environments.
3. Understanding how the structure of microhabitats—particularly the physical properties of rocks, such as porosity and pore size—shapes microbial communities across diverse dryland regions.
4. Defining the physical and chemical limits that allow life to persist at the very edges of habitability. This sheds light on the resilience—and fragility—of these tiny but vital organisms in a changing world.
This research is advancing understanding of how microbial communities function, adapt, and survive in dryland ecosystems—offering valuable insights into biodiversity conservation as aridity continues to rise.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

The DRYLIFE project is advancing our understanding of how microbial communities survive and adapt in some of the planet’s driest regions, focusing on the transition from arid to hyper-arid environments.
In the first phase, rocks, soils, and biological crusts were collected across 20 protected areas in the Western USA, covering a broad aridity gradient. This allowed the team to compile a rich dataset of microbial diversity, revealing new bacterial and fungal taxa and building the foundation for future biogeographic comparisons.
Significant progress has also been made in decoding the genetic traits that allow rock-dwelling microbes to endure extreme conditions like drought and solar radiation. Innovative computational tools were developed to analyze over multi-omics datasets, including the creation of a pipeline for assembling eukaryotic genomes—an open resource now available to the scientific community.
To explore the influence of rock properties on microbial life, detailed mineralogical and microscopic analyses were performed. These revealed how factors like porosity and chemical composition shape microbial communities across varying drylands.
Finally, to understand the limits of life in extreme dryness, environmental data and microbial profiles were integrated into predictive models. Comparisons between US and Antarctic drylands are ongoing to pinpoint universal strategies microbes use to survive in hyper-arid ecosystems.
Throughout the project, the researcher received extensive training in bioinformatics, environmental modelling, and machine learning, enhancing both technical and analytical skills. Knowledge was shared through mentoring, and joint fieldwork, creating a dynamic exchange between US and European research institutions and paving the way for long-term collaboration in dryland science.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The DRYLIFE project has made substantial progress toward its objectives, generating promising preliminary results that are paving the way for impactful outcomes.
- Microbial Diversity across Aridity Gradients: sampling and sequencing efforts have successfully revealed initial patterns of microbial diversity across gradients of aridity, from sub-humid to hyper-arid regions. Preliminary amplicon sequencing data highlight the presence of unique bacterial and fungal taxa, indicating shifts in community composition as aridity increases. This progress lays the groundwork for more detailed analyses of microbial biogeographic patterns.
- Genomic Traits Underpinning Stress Resistance: Shotgun metagenomic sequencing has provided early insights into the genomic adaptations of endolithic microbial communities. The development of a novel bioinformatics pipeline for genome assembly has been a critical milestone, broadening the potential for future studies.
- Role of Microhabitat Properties: preliminary analyses of rock samples have shown how porosity, mineral composition, and organic carbon content influence microbial colonization. These initial results indicate correlations between rock properties and microbial diversity, providing a basis for further exploration of abiotic-biotic interactions in extreme environments.
- Predictive Models of Ecosystem Resilience: the integration of environmental and biological datasets is underway, with initial comparative analyses between US drylands and Antarctic ecosystems suggesting shared stress adaptation mechanisms. These early results will contribute to the refinement of predictive models linking microbial diversity to environmental gradients.

Potential Impacts:
- Advancing Knowledge of Dryland Ecosystems: the project is generating valuable data on microbial diversity and adaptations in some of the most challenging environments on Earth. This foundational knowledge will support future research on the resilience of drylands under global climate change.
- Conservation of Microbial Biodiversity: by identifying microbial taxa and their functional roles, DRYLIFE highlights the importance of protecting microbial communities as key components of dryland ecosystems. This is especially critical as these regions face increasing pressures from desertification and climate change.
- Methodological and Technological Innovation: the development of new bioinformatics tools and datasets is creating opportunities for cross-disciplinary research and applications in microbial ecology, geology, and climate science.
- Future Applications in Climate Change and Astrobiology: the study of microbial adaptations to extreme aridity has implications for understanding life’s potential under future climate scenarios on Earth and exploring habitability in extraterrestrial environments.