EMERGE 2016 Autochamber Sites NMR METHODS: ​​To follow bio-available metabolites, we used NMR on the water extracted supernatant samples. Supernatant samples (180 µL) were combined with 2,2-dimethyl-2-silapentane-5-sulfonate-d6 (DSS-d6) in D2O (20 µL, 5 mM) and thoroughly mixed prior to transfer to 3 mm NMR tubes. NMR spectra were acquired on a Bruker Neo spectrometer operating at 18.8T (1H ν0 of 800.30 MHz) equipped with a 5mm Bruker TCI/CP HCN (inverse) cryoprobe with Z-gradient.at a regulated temperature of 298.0 K. The 90° 1H pulse was calibrated prior to the measurement of each sample. The one-dimensional 1H spectra were acquired using a nuclear Overhauser effect spectroscopy (noesypr1d) pulse sequence with a spectral width of 20.1 ppm and 2048 transients. The NOESY mixing time was 100ms and the acquisition time was 4s followed by a relaxation delay of 1.5 s during which presaturation of the water signal was applied. The 1D 1H spectra were manually processed, assigned metabolite identifications and quantified using Chenomx NMR Suite 9.0. Time domain free induction decays (65536 total points) were zero filled to 131072 total points prior to Fourier transform, followed by exponential multiplication (0.3 Hz line-broadening), and semi-automatic multipoint smooth segments baseline correction. Chemical shifts were referenced to the 1H methyl signal in DSS-d6 at 0 ppm. Metabolite identification was based on matching the chemical shift, J-coupling and intensity of experimental signals to compound signals in the Chenomx, HMDB and custom in-house databases (Supplementary Data X). Quantification was based on fitted metabolite signals relative to the internal standard (DSS-d6). Signal to noise ratios (S/N) were checked using MestReNova 14.1 with the limit of quantification equal to a S/N of 10 and the limit of detection equal to a S/N of 3. FUNDING: This research is a contribution of the EMERGE Biology Integration Institute, funded by the National Science Foundation, Biology Integration Institutes Program, Award # 2022070. We thank the Swedish Polar Research Secretariat and SITES for the support of the work done at the Abisko Scientific Research Station. SITES is supported by the Swedish Research Council’s grant 4.3-2021-00164. This study was also funded by the Genomic Science Program of the United States Department of Energy Office of Biological and Environmental Research, grant #s DE-SC0010580 and DE-SC0016440. A portion of this research was performed under the Facilities Integrating Collaborations for User Science (FICUS) exploratory effort and used resources at the Environmental Molecular Sciences Laboratory (proposal ID 51858), which are DOE Office of Science User Facilities. A portion of the research has been performed using EMSL (grid.436923.9), a DOE Office of Science User Facility sponsored by the Office of Biological and Environmental Research.