ESI-FTICR-MS Analysis of Organic Matter during Incubations with Nitrogen Addition, Teller Road Site, Seward Peninsula, Alaska

DOI: https://doi.org/10.5440/1631035
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NGEE Arctic Record ID: NGA228
Data Version: 1.0
Abstract

This dataset contains the results of the molecular characterization of water-extractable organic matter collected during soil microcosm incubations of tundra soil. The microcosms contained soil collected in April 2017 from the NGEE Arctic Teller Road Site at mile marker 27 (TL_MM27) near Intensive Site 9 (“Toeslope”) and Intensive Site 5 (“Plateau”). The incubations were conducted under an atmosphere of N2 at 8°C for 55 days, with or without addition of ammonium chloride (NH4Cl). Soils were extracted with deionized water and extracted using Bond Elut PPL cartridges prior to analysis. Molecular characterization was performed using electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI- FTICR-MS). 

Two data files are provided with this dataset. The first is the summary, by soil type and treatment, of the mass spectrometry results for formulas (as a % of the total) containing C, H, and O only, and with N, S, and other elements. These formulas were then grouped into nine biochemical classes of compounds based on O:C and H:C ratios. The second file provides soil sample characteristics and the processed high-resolution mass spectrometry results by soil type and treatment.

The Next-Generation Ecosystem Experiments: Arctic (NGEE Arctic), was a 10-year research effort (2012-2022) to reduce uncertainty in Earth System Models by developing a predictive understanding of carbon-rich Arctic ecosystems and feedbacks to climate. NGEE Arctic was supported by the Department of Energy’s Office of Biological and Environmental Research.

The NGEE Arctic project had two field research sites: 1) located within the Arctic polygonal tundra coastal region on the Barrow Environmental Observatory (BEO) and the North Slope near Utqiagvik (Barrow), Alaska and 2) multiple areas on the discontinuous permafrost region of the Seward Peninsula north of Nome, Alaska.

Through observations, experiments, and synthesis with existing datasets, NGEE Arctic provided an enhanced knowledge base for multi-scale modeling and contributed to improved process representation at global pan-Arctic scales within the Department of Energy’s Earth system Model (the Energy Exascale Earth System Model, or E3SM), and specifically within the E3SM Land Model component (ELM).

Authors
Hongmei Chen (hchen015@odu.edu) 0000-0003-2460-838X
Michael Philben (philben@hope.edu) 0000-0002-8598-9043
David Graham (grahamde@ornl.gov) 0000-0001-8968-7344
Baohua Gu (gub1@ornl.gov) 0000-0002-7299-2956
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Dataset Citation
Hongmei Chen, Michael Philben, David Graham, Baohua Gu. 2020. ESI-FTICR-MS Analysis of Organic Matter during Incubations with Nitrogen Addition, Teller Road Site, Seward Peninsula, Alaska. Next Generation Ecosystem Experiments Arctic Data Collection, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, USA. Dataset accessed on [INSERT_DATE] at https://doi.org/10.5440/1631035.
Dates
2017-06-01 - 2017-06-01
Geographic Location
NGEE Arctic Teller Site, Mile Marker 27, Alaska
North64.758839
South64.712145
East-165.921485
West-165.979295
Place Keywords:
N/A
Subject Keywords:
soil organic matter | low molecular weight carbon fraction |
GCMD Keywords
EARTH SCIENCE > LAND SURFACE > SOILS
Methodology
Study site and soil collection Soil cores were collected from two locations within the same watershed in the Teller Road mile 27 site of the Next Generation Ecosystem Experiment (NGEE)-Arctic. One site (hereafter “Plateau”) is located on a peat plateau on the top of the hillslope (64.74514°N, 165.966551°W), and the other site (“Toeslope”) is located at the base of the hillslope (64.729193°N, 165.944072°W). Both sites are characterized by tussock tundra, sedge-dominated vegetation, and a water table at or near the soil surface. Cores from the two sites were collected in spring of 2017 prior to the thawing of the active layer. The core from the plateau was 76 cm in length, and the toeslope core was 84 cm. The cores were shipped frozen to Oak Ridge National Laboratory and stored frozen until the start of the incubation. The frozen cores were transferred to an anaerobic chamber and separated into organic and mineral soil layers based on visual inspection. The uppermost layers containing intact vegetation were removed. The 0-38 cm and 0-34 cm intervals were characterized as organic for the toeslope and the plateau soils, respectively. Core sections from 38-84 cm for the toeslope and 61-76 cm for the plateau were used as the mineral soil. Microcosm construction The separated cores were cut into small (<0.5 cm3) pieces using an oscillating cutting tool and mixed with a spoon, creating four homogenized samples (organic and mineral soils for the toeslope and the plateau). Soil microcosms were prepared by adding 7 g (wet soil) to 60 mL serum bottles. 1 mL of either MilliQ water (control treatment) or NH4Cl solution containing 32 mM N (+N treatment) was added to each microcosm. Three replicate microcosms were prepared for the control and +N treatments to be incubated at 8°C for 55 days. There were therefore 96 microcosms in total. The microcosms were sealed with blue rubber septa, crimped with aluminum caps, flushed with N2 for 10 minutes, and transferred to incubators at the appropriate temperature. The incubations were conducted under an atmosphere of N2 at 8°C for 55 days, with or without addition of ammonium chloride (NH4Cl). Soils were extracted with deionized water and extracted using Bond Elut PPL cartridges prior to analysis. Molecular characterization was performed using electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR-MS). Please see Chen et al. (2018) for details. Using ultrahigh-resolution mass spectrometry, we determined the susceptibility and compositional changes of extractable dissolved organic matter (EDOM) in an anoxic incubation experiment with Toeslope and Plateau tundra soils from Alaska (United States). EDOM was extracted from both the organic- and mineral-layers of both soils following incubation. Based on their O:C and H:C ratios, EDOM molecular formulas were qualitatively grouped into nine biochemical classes of compounds.
Related References
Philben, M., TaÅŸ, N., Chen, H., Wullschleger, S. D., Kholodov, A., Graham, D. E., & Gu, B. ( 2020). Influences of hillslope biogeochemistry on anaerobic soil organic matter decomposition in a tundra watershed. Journal of Geophysical Research: Biogeosciences, 125, e2019JG005512. https://doi.org/10.1029/2019JG005512
Related Identifiers
Identifier: 10.1029/2019JG005512
Type: DOI
Relation: IsCitedBy
Metadata Contact
Contact information for the individual or organization that is knowledgeable about the data.
Person: Michael Philben
Organization: Oak Ridge National Laboratory
Email: philbenmj@ornl.gov
Point of Contact
Contact information for the individual or organization that is knowledgeable about the data.
Person: Baohua Gu
Organization: ORNL
Email: gub1@ornl.gov
Dataset Usage Rights
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Distribution Point of Contact
Contact: Data Center Support
Organization: Next-Generation Ecosystem Experiments (NGEE) Arctic Project, Oak Ridge National Laboratory
Email: support@ngee-arctic.ornl.gov