A5090886044- Peatlands and Wetlands Ecology
- Fire effects on ecosystems
- Climate change and permafrost
- Coastal wetland ecosystem dynamics
- Geology and Paleoclimatology Research
- Botany and Plant Ecology Studies
- Soil and Water Nutrient Dynamics
- Atmospheric and Environmental Gas Dynamics
- Soil Carbon and Nitrogen Dynamics
- Cryospheric studies and observations
- Rangeland and Wildlife Management
- Marine and coastal ecosystems
- Forest ecology and management
- Hydrology and Watershed Management Studies
- Lichen and fungal ecology
- Mercury impact and mitigation studies
- Forest Ecology and Biodiversity Studies
- Fish Ecology and Management Studies
- Forest Biomass Utilization and Management
- Groundwater and Isotope Geochemistry
- Atmospheric chemistry and aerosols
- Forest Management and Policy
- Methane Hydrates and Related Phenomena
- Ecology and Vegetation Dynamics Studies
- Soil Geostatistics and Mapping
Michigan Technological University
2015-2024
Northern Research Station
2015-2024
Wake County Human Services
2024
Houghton University
2024
US Forest Service
2010-2022
United States Department of Agriculture
2019-2022
Syracuse University
2022
Rocky Mountain Research Station
2022
Texas Tech University
2019
CHRISTUS Spohn Hospital Corpus Christi - Memorial
2019
Permafrost degradation in peatlands is altering vegetation and soil properties impacting net carbon storage. We studied four adjacent sites Alaska with varied permafrost regimes, including a black spruce forest on peat plateau permafrost, two collapse scar bogs of different ages formed following thermokarst, rich fen without permafrost. Measurements included year-round eddy covariance estimates dioxide (CO
We evaluated the utility of composite burn index (CBI) for estimating fire severity in Alaskan black spruce forests by comparing data from 81 plots located 2004 and 2005 events. collected to estimate CBI quantify crown damage, percent trees standing after fire, depth organic layer remaining burning surface (absolute relative), substrate exposed fire. To pre-fire depth, we 15 unburned stands develop relationships between total measures adventitious root above mineral soil below layer....
Rich fens are common boreal ecosystems with distinct hydrology, biogeochemistry and ecology that influence their carbon (C) balance. We present growing season soil chamber methane emission (FCH4 ), ecosystem respiration (ER), net exchange (NEE) gross primary production (GPP) fluxes from a 9-years water table manipulation experiment in an Alaskan rich fen. The study included major flood drought years, where wetting drying treatments further modified the severity of droughts. Results support...
Widespread changes in arctic and boreal Normalized Difference Vegetation Index (NDVI) values captured by satellite platforms indicate that northern ecosystems are experiencing rapid ecological change response to climate warming. Increasing temperatures altered hydrology driving shifts ecosystem biophysical properties that, observed satellites, manifest as long-term regional NDVI. In an effort examine the underlying drivers of these changes, we used field-scale remote sensing NDVI track...
The high water retention of hummock-forming Sphagnum species minimizes soil moisture fluctuations and might protect forest floor organic matter from burning during wildfire. We hypothesized that cover reduces overall consumption wildfire compared with other ground-layer vegetation. characterized variability in layer depth stocks two pairs burned unburned black spruce ( Picea mariana (Mill.) BSP) stands interior Alaska. In the stands, microsites dominated by had more than twice as much...
Climate warming and permafrost degradation at high latitudes will likely impact watershed hydrology, consequently, alter the concentration character of dissolved organic carbon (DOC) in northern rivers. We examined seasonal variation DOC chemistry 16 streams Yukon River basin, Alaska. Our primary objective was to evaluate relationship between source water (shallow versus deep groundwater flow paths) chemical composition. Using base cation principal component analysis, we observed...
Dissolved organic carbon (DOC) production, consumption, and quality displayed differences after long-term (~55 years) hydrological alterations in a poor fen peatland northern Michigan. The construction of an earthen levee resulted areas raised lowered water table (WT) relative to unaltered intermediate WT site. site had greater peat aeration larger seasonal vertical fluctuations that likely elevated decomposition subsidence with subsequent increases bulk density, hydraulic gradient,...
Abstract Arctic and boreal ecosystems are experiencing pronounced warming that is accelerating decomposition of soil organic matter releasing greenhouse gases to the atmosphere. Future carbon storage in these depends on balance between microbial primary production, both which can be regulated by nutrients such as phosphorus. Phosphorus cycling tundra regions often assumed occur through biological pathways with little interaction minerals; is, phosphate released from molecules rapidly...
Abstract Peatlands contain a significant fraction of global soil carbon, but how these reservoirs will respond to the changing climate is still relatively unknown. A picture variations in peat organic matter chemistry aid our ability gauge peatland response climate. The goal this research test hypotheses that (a) carbohydrate content, an indicator reactivity, increase with latitude and decrease mean annual temperatures, (b) while aromatic recalcitrance, vary inversely, (c) elevation have...
We measured characteristics of soil organic carbon (SOC) and black (BC) along opposed north‐ south‐facing toposequences in recent (2004) old (∼1860–1950) burn sites throughout interior Alaska. Surface fuel consumption did not vary between different topographic positions, with 3.3 (±0.5) kg C m −2 being consumed on toe slope sites, 4.0 (±0.2) north‐slope 3.6 (±0.3) south‐slope sites. On a relative scale, 43% the matter depth was removed through biomass burning slopes, 62% north‐slopes, 77%...
Boreal wetland carbon cycling is vulnerable to climate change in part because hydrology and the extent of frozen ground have strong influences on plant microbial functions. We examined response dissolved organic (DOC) total nitrogen (TDN) across an experimental manipulation water table position (both raised lowered treatments) a boreal‐rich fen interior Alaska. DOC TDN responses exhibited interaction with seasonal ice dynamics. observed consistently higher concentrations treatment (71.7 ±...
It is important to understand the fate of carbon in boreal peatland soils response climate change because a substantial release this as CO2 and CH4 could influence system. The goal research was synthesize results field water table manipulation experiment conducted rich fen into process-based model how soil organic (SOC) might respond projected change. This model, version dynamic Terrestrial Ecosystem Model (peatland DOS-TEM), calibrated with data collected during 2005-2011 from control...
Abstract Questions How does fire severity, measured as depth of burn ground layer fuels, control the regeneration understorey species across black spruce‐dominated stands varying in pre‐fire organic depths? Are successional shifts from evergreen to deciduous vegetation more likely occur with greater burn? Does a shift community towards influence carbon accumulation biomass? Location Northern boreal forest, interior Alaska. Methods We sampled 32 Alaska that burned 2003 and 2004 which had been...