Vegetation Warming Experiment: 15N Uptake Experiment Arctagrostis latifolia Root Traits, Utqiagvik (Barrow), Alaska, 2018

DOI: https://doi.org/10.5440/1784749
NGEE Arctic Record ID: NGA257
Data Version: 1.0
Abstract

This dataset consists of measured A. latifolia root traits (specific root length (SRL), mass, length, C and N content) from vegetation warming experiment enclosures and paired control plots located on the BEO, Utqiaġvik, Alaska.

Vegetation warming chambers (Zero Power) were deployed on the Barrow Environmental Observatory (BEO), Utqiaġvik, Alaska. These chambers (Figure 1) consistently elevated air temperatures by approximately 4°C using a self-venting system described by Lewin et al (2017). Five chambers were deployed from June 17, 2018 to September 24, 2018 on the BEO within a 1 km2 area centered on 71.275N, -156.641W. Each chamber was co-located with an ambient plot where temperatures were not manipulated on patches of tundra containing the target species Arctagrostis latifolia. An intensive field campaign in late July investigated the impact of warming had on A. latifolia biomass, chemistry, and uptake of 15N labeled ammonia that was injected into the surface soils for one week. Initial measurements were taken on July 21, 2018. Harvest occurred on July 27, 2018. Water-extractable nutrients in soils were measured in July following harvests of A. latifolia plants and underlying soils. Availability of ammonia, nitrate, and phosphate throughout the growing season was measured by extracting nutrients bound to anion and cation binding resins deployed from July through September. Environmental variables (thaw depth, surface soil temperatures, surface soil moisture) were measured. Leaf traits and root traits of A. latifolia were also measured.

The Next-Generation Ecosystem Experiments: Arctic (NGEE Arctic), was research effort 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
Verity Salmon (salmonvg@ornl.gov) 0000-0002-2188-551X
Joanne Childs (childsj@ornl.gov) 0000000220027337
Colleen Iversen (iversencm@ornl.gov) 0000000182933450
Breann Spencer (shangping888@gmail.com)
Alistair Rogers (arogers@bnl.gov) 0000-0001-9262-7430
Kim Ely (kely@bnl.gov) 0000-0002-3915-001X
Shawn Serbin (sserbin@bnl.gov) 0000-0003-4136-8971
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Dataset Citation
Verity Salmon, Joanne Childs, Colleen Iversen, Breann Spencer, Alistair Rogers, Kim Ely, Shawn Serbin. 2021. Vegetation Warming Experiment: 15N Uptake Experiment Arctagrostis latifolia Root Traits, Utqiagvik (Barrow), Alaska, 2018. 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/10.5440/1784749.
Dates
2018-07-27 - 2018-07-27
Geographic Location
NGEE Arctic Utqiagvik (Barrow), Alaska
North71.35
South71.2
East-156.4
West-156.7
Place Keywords:
Utqiagvik, Alaska | Barrow Environmental Observatory (BEO), Alaska
Subject Keywords:
rhizome biomass | fine root biomass |
GCMD Keywords
EARTH SCIENCE > BIOSPHERE > VEGETATION
Methodology
Warming treatment was implemented in Utqiagvik, Alaska on the Northern coastal plain using Zero Power Warming chambers that elevate air temperatures by approximately 4°C . Details on design and impact of the warming chambers are documented in Lewin and others (2017). At one location within each chambered plot and co-located ambient plot, 9 x 9 cm areas of A. latifolia were harvested. A serrated knife was used to cut the organic layer (approximately 8 cm in depth) into a square block. Organic soil and intact vegetation were then removed together. To sample roots and soils beneath the organic layer, a soil core was collected from within the footprint of the harvested block (diameter=5 cm). Soil cores spanned the bottom of the organic horizon to frozen ground. Immediately following collection, soil cores were separated in into 5 cm depth intervals. All equipment was wiped down with ethanol between plots to prevent isotopic contamination. Organic horizon samples were taken to the field lab where A. latifolia biomass was separated from organic soils within 48 hours and sorted by tissue type (attached litter, blades, sheaths, inflorescences, rhizomes, fine roots). Plant materials were then dried at 65°C for 24 hours. In the field lab, organic soil samples and soil cores were also subsampled for bulk density, gravimetric water content, and bulk soil %C and %N. All soil samples were then frozen and shipped to Oak Ridge National Laboratory, Oak Ridge, TN (ORNL) for further processing. At two replicate locations within each chambered plot and co-located ambient plot, a trace amount of 15N was introduced to the soil pool with a 15N-NH4Cl solution (2.4 mmol 15N-NH4Cl L-1; Sigma Aldrich >= 98 atom% 15N, Lot # MBBC2459). The solution was injected using a spinal port needle inserted to 3 cm depth. Each labeled area was 12 x 12 cm and injections were performed at 3 cm intervals in a gridded pattern. At each of the 16 injection points, a 5 ml aliquot of the 15N-NH4Cl solution was injected. Test injections of food coloring into the soil at this site revealed that the diffusion of this solution volume was approximately 1.5 cm- this method therefore ensured we applied a consistent, even label of +200 mg 15N m-2 (similar to loading in McKane et al., 2002). To protect 15N-labeled vegetation from herbivores, a wire mesh cage was installed around each injection area. After a period of six days, the inner 9 x 9 cm of each 15N-labeled area was harvested following the protocol described above. Fine roots and rhizomes of A. latifolia were removed from all remaining frozen soil materials. After removal from the soil, roots were rinsed with a 0.01M CaCl solution for 30 seconds and then rinsed in DI water to remove any 15N on the root surface that had not been taken up into the root tissue. After rinsing, fine roots were laid in acrylic trays of DI water and scanned using a WinRhizo scanner and WinRhizo 2012 Reg software (Regent Instruments Inc., Canada) at 1400 DPI. Fine root length and diameter were extracted from images. The fine roots and rhizomes were then dried and weighed prior to being ground to a homogenous powder using a Geno/Grinder 2010 (SpexSamplePrep, Metuchen, New Jersey, USA) Tissue-specific %C and %N were analyzed on a Costech ECS 4010 CHNSO elemental analyzer (Costech Analytical Technologies, Inc Valencia, CA, USA). If fine root tissue samples were too small to run for %N and %C, they were combined with fine root samples from adjacent depths. Any remaining gaps in chemistry data were filled with averages values from replicate harvests in the same plot for %N or from cross plot averages per tissue type %C.
Related References
Verity Salmon, Joanne Childs, Colleen Iversen, Breann Spencer, Alistair Rogers, Kim Ely, Shawn Serbin. 2021. Vegetation Warming Experiment: 15N Uptake Experiment Arctagrostis latifolia Canopy Traits, Utqiagvik (Barrow), Alaska, 2018. Next Generation Ecosystem Experiments Arctic Data Collection, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, USA. https://doi.org/10.5440/1784759
Verity Salmon, Joanne Childs, Colleen Iversen, Breann Spencer, Alistair Rogers, Kim Ely, Shawn Serbin. 2021. Vegetation Warming Experiment: 15N Uptake Experiment Environmental Observations and Thaw Depth, Utqiagvik (Barrow), Alaska, 2018. Next Generation Ecosystem Experiments Arctic Data Collection, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, USA. https://doi.org/10.5440/1784757
Verity Salmon, Joanne Childs, Colleen Iversen, Breann Spencer, Alistair Rogers, Kim Ely, Shawn Serbin. 2021. Vegetation Warming Experiment: 15N Uptake Experiment Arctagrostis latifolia Biomass and Chemistry, Utqiagvik (Barrow), Alaska, 2018. Next Generation Ecosystem Experiments Arctic Data Collection, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, USA. https://doi.org/10.5440/1784750
Verity Salmon, Joanne Childs, Colleen Iversen, Breann Spencer, Alistair Rogers, Kim Ely, Shawn Serbin. 2021. Vegetation Warming Experiment: 15N Uptake Experiment Arctagrostis latifolia 15N Uptake, Utqiagvik (Barrow), Alaska, 2018. Next Generation Ecosystem Experiments Arctic Data Collection, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, USA. https://doi.org/10.5440/1784751
Verity Salmon, Joanne Childs, Colleen Iversen, Breann Spencer, Alistair Rogers, Kim Ely, Shawn Serbin. 2021. Vegetation Warming Experiment: 15N Uptake Experiment Inorganic Nitrogen and Phosphorus on Resins, Utqiagvik (Barrow), Alaska, 2018. Next Generation Ecosystem Experiments Arctic Data Collection, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, USA. https://doi.org/10.5440/1784752
Verity Salmon, Joanne Childs, Colleen Iversen, Breann Spencer, Alistair Rogers, Kim Ely, Shawn Serbin. 2021. Vegetation Warming Experiment: 15N Uptake Experiment Water-Extractable Soil Nutrients, Utqiagvik (Barrow), Alaska, 2018. Next Generation Ecosystem Experiments Arctic Data Collection, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, USA. https://doi.org/10.5440/1784755
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Related Identifiers
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Metadata Contact
Contact information for the individual or organization that is knowledgeable about the data.
Person: Verity Salmon
Organization: Oak Ridge National Laboratory
Email: salmonvg@ornl.gov
Point of Contact
Contact information for the individual or organization that is knowledgeable about the data.
Person: Verity Salmon
Organization: Oak Ridge National Laboratory
Email: salmonvg@ornl.gov
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