Linking soil microbial stress metabolism to watershed biogeochemistry under climate change across seasons
EMSL Project ID
60427
Abstract
Air temperatures are rising, while the winter snowpack is shrinking and soil freeze/thaw events are increasing in high latitude ecosystems. The severe thermal perturbations from warming during the growing season and freeze/thaw cycles in winter shift the amount of dissolved organic C (DOC), dissolved inorganic N (DIN), and CO2 flux from soils of forested watersheds. However, it is unclear how these changes are linked to observed shifts in soil microbial community composition and activity, or how microbial-driven shifts in biogeochemical cycling activity impacts C and nutrient retention vs. export to coupled aquatic ecosystems. The objective of this proposed research is to improve mechanistic understanding and model representation of the combined effects of warming during the growing season and soil freeze/thaw cycles in winter on belowground biogeochemical cycles in northeastern forests. To address this objective, we propose a model-data integration study using the Climate Change Across Seasons Experiment (CCASE) at the Hubbard Brook Experimental Forest (HBEF) and a complementary plot-to-watershed-level biogeochemistry model, PnET-BGC. Our previous collaborative work with JGI showed that initially, CCASE treatments selected for anaerobic N cycling bacteria and fungi that have higher genetic capability for redox stress regulation, including the capacity to oxidize iron instead of DOC. We propose to explore these links between microbial stress regulation and C, N, and iron cycling further to understand their relationship to watershed-relevant biogeochemical dynamics by coupling soil metagenomics (JGI), metaproteomics (EMSL), and SOM composition (EMSL) to new belowground biogeochemistry measurements at CCASE (net and gross soil C, N, iron, and P fluxes, and DOC/N/P chemodiversity in soil solution) we are collecting as part of a new funded DOE BER ESS award. We request 0.540 Tb of 150PE Illumina NovaSeq sequencing from JGI for metagenomes on newly preserved soil samples (12 samples). We also request isotopic analysis (IRMS, EMSL) on roots (48 samples) and SIP metagenomes on soils (24 samples) from a new 15N tracer experiment to partition N between free-living microbes, plant roots, and soil solution under CCASE treatments and to quantify the plant and microbial processes responsible for N retention and export from forest soil. Plant and microbial C, N, and P cycling responses to CCASE treatments will be incorporated into new versions of PnET-BGC, with model outputs validated with existing forest C, N, and P pool and flux data from the HBEF watershed.
Project Details
Project type
FICUS Research
Start Date
2022-10-01
End Date
N/A
Status
Active
Released Data Link
Team
Principal Investigator
Co-Investigator(s)
Team Members