Probing Microbial Interactions and Coordinated Trophic Responses in Biological Soil Crusts
EMSL Project ID
50356
Abstract
Arid and semiarid lands comprise about 40% of the global land surface, and yet they are among the least understood ecosystems. Cryptogamic or biological soil crusts (BSC) are the dominant ground cover in these drylands and have a critical role in maintaining ecosystem functions with dramatic impacts on global nitrogen and carbon cycles. BSCs carry out important ecological services such as carbon and nitrogen fixation, the production of soil organic matter, soil water retention, redistribution of rainfall runoff, the provision of food sources for microflora and fauna, and the facilitation of vascular plant growth. Owing to pollution and human-induced disturbance, BSCs are highly threatened and are in need of conservation, rehabilitation, and restoration. As cooperative communities of eukaryotic and prokaryotic microbes that include fungi, bacteria, photosynthetic algae, and nitrogen-fixing cyanobacteria, BSCs function as ecosystem pioneers in colonizing bare terrestrial surfaces in low-water, extreme temperature environments. The microbial basis for BSC form and function, and how microbes interact in a coordinated fashion to produce the aforementioned BSC services, however, are poorly understood. This proposal focuses on understanding how BSC microbes interact--metabolically and physically--to impact one aspect of BSC ecosystem service and function: that of collective carbon and nitrogen cycling. To do this, we will leverage the outstanding capabilities and technical expertise at the EMSL and the JGI, and exploit an unusual property of BSCs that make them excellent experimental study systems. Microbes in desiccated crusts exist primarily in a low metabolic, dormant state but rapidly reanimate upon the addition of water. Using whole-community metagenomics, metatranscriptomics, proteomics, metabolomics, NanoSIMS, CARD-FISH, and BONCAT-FACS, we will develop a holistic view of the microbial processes underlying BSC metabolic reactivation upon wetting. By using stable-isotope labeling of water, nitrogen gas, and carbon dioxide during the wetting process, we will be able to produce an integrated phylo-trophic map detailing the flow and exchange of carbon and nitrogen between key microbial taxa within BSCs. We expect our findings to be foundational for understanding the microbial community structure of BSCs and the emergent ecosystem functions of crusts.
Project Details
Project type
FICUS Research
Start Date
2018-10-01
End Date
2022-04-21
Status
Closed
Released Data Link
Team
Principal Investigator
Co-Investigator(s)
Team Members