Biological Soil Crust Communities
I focus on drylands because they currently cover nearly 45% of the total Earth continental area, and host over 38% of the human population, making them a crucial ecosystem in terms of biodiversity and human well-being, especially in a warming world.
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Biocrust are natural topsoil communities typical form drylands. They are formed primary by photoautotrophic and heterotrophic bacteria. These communities provide important ecosystem services to drylands including soil protection against erosion, and nutrient fertilization.
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Selected Current Projects
If you want to learn more about my research please check my publications tab.
Biocrusts eat dust
2020 – ongoing
I recently started a new project investigating how biocrust’s ability to trap dust facilitates fertilization of drylands. I am interested in studying how these microbial communities respond to dust nutrients inputs and how these nutrient inputs are mobilized both within the biocrust and to the soil layers beneath. This research will aid in understanding the role of understudied microbial communities in the cycling of macro- and micronutrients which are considered major players in regulating the productivity of drylands.
The cyanosphere
2016 – ongoing
The bundle-forming, filamentous, non-nitrogen fixing cyanobacterium Microcoleus vaginatus is a pioneer primary producer, often the dominant member of the biocrust microbiome, and the main source of leaked organic carbon. M. vaginatus shapes the microbial populations of heterotrophs around it, forming a specialized cyanosphere (by analogy to the rhizosphere of plant roots), that concentrates the nitrogen fixing function. A mutualism based on C for N exchange between M. vaginatus and copiotrophic diazotrophs helps sustains this cyanosphere, a consortium that constitutes the true pioneer community enabling the colonization of nitrogen-poor soils.
For more information see:
2019 Spatial segregation of the biological soil crust microbiome around its foundational cyanobacterium, Microcoleus vaginatus, and the formation of a nitrogen-fixing cyanosphere. Microbiome. doi.org/10.1186/s40168-019-0661-2.
2020 A symbiotic nutrient exchange within the cyanosphere microbiome of the biocrust cyanobacterium, Microcoleus vaginatus. ISMEJ. doi.org/10.1038/s41396-020-00781-1
Biocrust Microbial Nursery
2013 – ongoing
Biocrust communities are very susceptible to human and climate change disturbances, and soils denuded of the community can naturally recover only very slowly. The biocrust microbial nursery constitutes a set of novel protocols to isolate, quantify and rapidly growth soil bacteria to develop and implement collaborative restoration strategies targeting the recovery of biocrusts cover in drylands and the rehabilitation of its ecosystems services. This set of protocols ultimately resulted in the construction of the ASU “mobile microbial nursery”, a self-sufficient field research station equipped with everything required for large scale on-site cultivation of microorganisms and phototrophic microbial communities in drylands.
For more information see:
2020 A fog-irrigated soil substrate system unifies and optimizes cyanobacterial biocrust inoculum production. Appl Environ Microbiolgy. doi.org/10.1128/AEM.00624-20.
2020 Microbial inoculum production for biocrust restoration: testing the effects of a common versus native soils on yield and community composition. Restoration Ecology. doi.org/10.1111/rec.13127.
2019 Effect of preconditioning to the soil environment on the performance of 20 cyanobacterial cultured strains used as inoculum for biocrust restoration. Restoration Ecology. doi.org/10.1111/rec.13048.
2019 Nursing biological soil crusts: isolation, biomass production, and fitness test of indigenous cyanobacteria. Restoration Ecology. doi.org/10.1111/rec.12920.
2019 Optimizing production of nursery-based biological soil crusts for restoration of arid lands soils. Appl Environ Microbiol. doi.org/10.1128/AEM.00735-19.
2019 Addressing barriers to improve biocrust colonization and establishment in restoration. Restoration Ecology. doi.org/10.1111/rec.13052.
2019 Inoculum and habitat amelioration efforts in biological soil crust recovery vary by desert and soil texture. Restoration Ecology. doi.org/10.1111/rec.13087.
2017 Microbial nursery production of high-quality biological soil crust biomass for restoration of degraded drylands soils. Appl Environ Microbiol. doi.org/10.1128/AEM.02179-16.
Ana Giraldo-Silva 