A5005630720- Methane Hydrates and Related Phenomena
- Seismic Waves and Analysis
- Ionosphere and magnetosphere dynamics
- Climate change and permafrost
- Cryospheric studies and observations
- Geology and Paleoclimatology Research
- Peatlands and Wetlands Ecology
- Geophysics and Gravity Measurements
- Soil and Unsaturated Flow
- Soil Carbon and Nitrogen Dynamics
- Indigenous Studies and Ecology
- Geological Studies and Exploration
- Clay minerals and soil interactions
- Soil Geostatistics and Mapping
- Polar Research and Ecology
- Atmospheric and Environmental Gas Dynamics
- Arctic and Antarctic ice dynamics
- Soil and Water Nutrient Dynamics
- Geochemistry and Geologic Mapping
- Marine and coastal ecosystems
- Groundwater and Isotope Geochemistry
- Aeolian processes and effects
- Soil and Environmental Studies
- Rangeland and Wildlife Management
- Hydrocarbon exploration and reservoir analysis
University of Alaska Fairbanks
2016-2025
Anhui Normal University
2024
Alaska Department of Natural Resources
2013-2017
University of Alaska System
2004-2013
Experimental Station
2003-2004
Agriculture and Agri-Food Canada
1995
Institute of Zoology
1932
Abstract. Soils and other unconsolidated deposits in the northern circumpolar permafrost region store large amounts of soil organic carbon (SOC). This SOC is potentially vulnerable to remobilization following warming thaw, but stock estimates were poorly constrained quantitative error lacking. study presents revised stocks, including uncertainty estimates, 0–3 m depth range soils as well for sediments deeper than 3 deltaic major rivers Yedoma Siberia Alaska. Revised are based on...
Deep soil profiles containing permafrost (Gelisols) were characterized for organic carbon (C) and total nitrogen (N) stocks to 3 m depths. Using the Community Climate System Model (CCSM4) we calculate cumulative distributions of active layer thickness (ALT) under current future climates. The difference in ALT over time was multiplied by C N contents horizons Gelisol suborders newly thawed N. Thawing ranged from 147 PgC with 10 PgN 2050 (representative concentration pathway RCP scenario 4.5)...
Approximately 1700 Pg of soil carbon (C) are stored in the northern circumpolar permafrost zone, more than twice as much C atmosphere. The overall amount, rate, and form released to atmosphere a warmer world will influence strength feedback climate change. We used survey quantify variability perception vulnerability Experts were asked provide quantitative estimates change response four scenarios warming. For highest warming scenario (RCP 8.5), experts hypothesized that release from zone...
Abstract. Knowledge of soils in the permafrost region has advanced immensely recent decades, despite remoteness and inaccessibility most sampling limitations posed by severe environment. These efforts significantly increased estimates amount organic carbon stored permafrost-region improved understanding how pedogenic processes unique to environments built enormous stocks during Quaternary. This knowledge also called attention importance permafrost-affected global cycle potential...
Heterogeneous environmental controls on permafrost region soil organic carbon stocks can now be quantified with spatial modeling.
Abstract. High-latitude terrestrial ecosystems are key components in the global carbon cycle. The Northern Circumpolar Soil Carbon Database (NCSCD) was developed to quantify stocks of soil organic (SOC) northern circumpolar permafrost region (a total area 18.7 × 106 km2). NCSCD is a geographical information system (GIS) data set that has been constructed using harmonized regional classification maps together with pedon from region. Previously, used calculate SOC storage reference depths 0–30...
Thermokarst lakes are potentially important sources of methane (CH4 ) and carbon dioxide (CO2 ). However, considerable uncertainty exists regarding emissions from thermokarst owing to a limited understanding their patterns motivators. In this study, we measured CH4 CO2 diffusive fluxes in 163 the Qinghai-Tibet Plateau (QTP) over 3 years May October. The median QTP were 1440 mg m-2 day-1 60 , respectively. rates related catchment land cover type. Sediment microbial abundance hydrochemistry...
Arctic warming may cause the release of vast amounts soil organic carbon (SOC) from permafrost, which will manifest itself in fluxes and composition northern rivers coastal regions. To elucidate transport pathways SOC, radiocarbon was measured for dissolved (DOC), particulate (POC), sediments SOC Mackenzie, Sagavanirktok, Yukon river basins, leaching experiments were conducted. The ages riverine suspended POC ranged 4430 to ∼7970 yr BP, while DOC much younger (390–1440 BP) except samples Sag...
Arctic landscapes have visually striking patterns of small polygons, circles, and hummocks. The linkages between the geophysical biological components these systems their responses to climate changes are not well understood. “Biocomplexity Patterned Ground Ecosystems” project examined patterned‐ground features (PGFs) in all five bioclimate subzones along an 1800‐km trans‐Arctic temperature gradient northern Alaska northwestern Canada. This paper provides overview transect illustrate trends...
Abstract Differences in the summer insulative value of zonal vegetation mat affect depth thaw along Arctic bioclimate gradient. Toward south, taller, denser plant canopies and thicker organic horizons counter effects warmer temperatures, so that there is little correspondence between active layer depths air temperature. We examined interactions warmth, (biomass, Leaf Area Index, Normalized Difference Vegetation Index), soil (texture pH), at 17 sites three subzones Slope Seward Peninsula,...
[1] Carbon, nitrogen, and material fluxes were quantified at 48 sampling locations along the 1957 km coastline of Beaufort Sea, Alaska. Landform characteristics, soil stratigraphy, cryogenic features, ice contents determined for each site. Erosion rates sites using satellite images aerial photos, averaged across increased from 0.6 m yr−1 during circa 1950–1980 to 1.2 1980–2000. Soils highly cryoturbated, organic carbon (OC) stores ranged 13 162 kg OC m−2 in banks above sea level 63 over...
The morphological, chemical, and physical properties of arctic tundra soils were examined along a 200‐km latitudinal gradient in northern Alaska which includes two major physiographic provinces; the Arctic Coastal Plain Foothills. Annual air temperature precipitation increase from north to south. Soils on support wet, nonacidic vegetation have high carbonate contents. Soil Foothills moist, part moist acidic southern part. Most are characterized by medium texture, poor drainage, organic...
Abstract Frost boils in northern Alaska vary from large, 2–3‐m diameter, barren non‐sorted circles to completely vegetated hummocks. Summer warmth increases southwards the coast. Average thaw‐layer thickness shows opposite trend. heave no trend along climate gradient but is affected by soil texture. Heave greatest on frost with fine‐grained sediments. Biomass 183 g m −2 at coast 813 Arctic Foothills. An aggrading permafrost table evident most of frost‐boil profiles, indicating that, over...
In arctic tundra, cryoturbation resulting from frost heave, cracking, and other cryogenic processes produces patterned ground such as nonsorted circles, stripes, polygons, earth hummocks. We studied structures morphological properties of soils associated with patterned‐ground features along a bioclimate gradient in Arctic Alaska Canada north (subzone A) to south E). Most these have strongly developed features, including warped broken horizons, organic matter moved into the upper permafrost....
Carbon dioxide respiration rates were measured in the laboratory at −2°C for 88 arctic Alaska soil horizon samples. Soil samples represented most ATLAS C‐flux study sites to a 1‐m depth. Sites extend across Arctic, from tundra Prudhoe Bay (70°N, 149°W) northeast tundra–forest transition zone of Seward Peninsula (64°N, 163°W) southwest, range nearly 1000 km. Results an initial temperature sensitivity indicated that 4°C, organic horizons (>20% carbon [OC]) have average are twice as high...