NGEE Arctic Plant Traits: Fine Roots, Kougarok Road Mile Marker 64, Seward Peninsula, Alaska, 2016

NGEE Arctic Record ID: NGA240
Data Version: 1.0

Soil cores were collected from twelve vegetation biomass plots at the Kougarok hillslope in late July of 2016. The sampled plots were located across six ecotypes present at this site (n=2 replicates per ecotype). Soil cores were separated into depth intervals in the field and frozen for transport to Oak Ridge National Laboratory. Data package contains one CSV and one pdf.

Laboratory sample processing of these soils generated depth-specific data on soil properties as well as fine root biomass, length, %C, %N, delta13C, and delta15N. Only live fine roots were analyzed. Fine roots were not separated by species or plant functional type.

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).

Verity Salmon ( 0000-0002-2188-551X
Colleen Iversen ( 0000-0001-8293-3450
Joanne Childs () 0000-0002-2002-7337
Dataset Citation
Verity Salmon, Colleen Iversen, Joanne Childs. 2021. NGEE Arctic Plant Traits: Fine Roots, Kougarok Road Mile Marker 64, Seward Peninsula, Alaska, 2016. 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
2016-07-25 - 2016-07-27
Geographic Location
NGEE Arctic Kougarok Site, Mile Marker 64, Alaska
Place Keywords:
Subject Keywords:
fine roots |
GCMD Keywords
Soil core collection Cores were collected on July 25 through July 27th, 2016 at the Kougarok hillslope site on the Seward Peninsula. Two cores were collected within each of the twelve biomass plots sampled and were designated core replicates A and B. A battery-powered drill and a modified diameter hole saw was used to extract soil cores. In most plots the hole saw had a 3” diameter but in the very rocky soil at the NAMC plots we used the 2 7/8" diameter hole saw collect cores. All cores were collected down to the depth of permafrost or rock. The depth of each hole was measured after core collection. In the NAMC plots, cores were collected in vegetated areas rather than in unvegetated soil. In TTWBT and TT plots where tussock forming sedges alter microtopography, cores were collected in tussocks. Immediately following collection, the total length of the core was checked and the depth of the organic layer was recorded. The core was then sectioned into 10-cm depth increments using either clippers (for organic soil) or a knife (mineral soil). If the organic-mineral transition occurred within a 10-cm depth increment, the sample was separated into smaller depth intervals. All samples were then designated part of the organic or mineral horizon. All soil samples were transported back to Nome in coolers and frozen for shipment to ORNL. Core Processing In the laboratory, soil samples from each depth interval were split vertically in half. One half was used for a determination of soil texture, gravimetric water content, bulk density, bulk soil %C and %N, and water extractable total nitrogen, inorganic nitrogen, phosphorus, and organic nitrogen. The remaining half of the soil core was used for determination of fine root biomass, rock volume and weight, and pH of root-free soil. Soil properties are reported in “NGEE Arctic Plant Traits: Soil Cores, Kougarok Road Mile Marker 64, Seward Peninsula, Alaska, 2016” Fine Root Biomass and Length The remaining half of the soil cores had all live fine roots (<2mm diameter) carefully removed. Only live roots were considered, and dead roots were identified as those that were 1) visibly ragged, hollow or flat (presumably due to from decomposition) 2) offered no resistance to being pulled apart by tweezers. Due to the potential presence of aerenchyma in some species present at the site, floating roots were not considered dead. For some plant communities (TT, WBT, DSLT) the extensive volume of fine roots and the matted, dense soil organic matter made picking half a core within one week of thaw impossible. In these instances, a smaller subsample was picked and scaled up based on live fine roots per cm3 soil. We found that fine roots could not reliably be attributed to specific plant functional types or species. After fine roots were removed from soil, they were carefully rinsed clean with DI water to remove all soil materials. Fine roots were then scanned for length using WinRhizo (Regent Instruments, Inc., Québec, Canada) at 1400 dpi to resolve the diameter of distal shrub fine roots that were often less than 100 μm. Fine roots were then oven-dried at 70 °C and weighed to determine root biomass. Fine Root %C, %N, delta13C, and delta15N Dried fine root samples were ground to a fine powder (SPEX SamplePrep 2010 Geno/Grinder, Metuchen, NJ). Samples were then sent to UC Davis Stable Isotope facility for determination of %C, %N, delta13C and delta15N.
Related References
Fry, B. (2006). Stable Isotope Ecology. Springer-Verlag.
Related Identifiers
Metadata Contact
Contact information for the individual or organization that is knowledgeable about the data.
Person: Verity Salmon
Organization: ORNL
Point of Contact
Contact information for the individual or organization that is knowledgeable about the data.
Person: Verity Salmon
Organization: ORNL
Dataset Usage Rights
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Organization: Next-Generation Ecosystem Experiments (NGEE) Arctic Project, Oak Ridge National Laboratory