A5042003457- Geology and Paleoclimatology Research
- Tree-ring climate responses
- Climate change and permafrost
- Plant Water Relations and Carbon Dynamics
- Fire effects on ecosystems
- Cryospheric studies and observations
- Landslides and related hazards
- Arctic and Antarctic ice dynamics
- Forest ecology and management
- Heavy metals in environment
- Geological Studies and Exploration
- Indigenous Studies and Ecology
- Pleistocene-Era Hominins and Archaeology
- Isotope Analysis in Ecology
- Archaeology and ancient environmental studies
- Marine and environmental studies
- Ecology and biodiversity studies
- Aquatic Ecosystems and Phytoplankton Dynamics
- Forest Ecology and Biodiversity Studies
- Methane Hydrates and Related Phenomena
- Mine drainage and remediation techniques
- Smart Materials for Construction
- Climate variability and models
- Diatoms and Algae Research
- Hydrology and Sediment Transport Processes
Brock University
2016-2025
University of Alberta
2021
Carleton University
2007-2021
University of New Brunswick
2021
Carleton College
2009
Montana State University
2002-2003
Queen's University
2001-2003
McMaster University
2001
An annually laminated succession in Crawford Lake, Ontario, Canada is proposed for the Global boundary Stratotype Section and Point (GSSP) to define Anthropocene as a series/epoch with base dated at 1950 CE. Varve couplets of organic matter capped by calcite precipitated each summer alkaline surface waters reflect environmental change global local scales. Spheroidal carbonaceous particles nitrogen isotopes record an increase fossil fuel combustion early 1950s, coinciding fallout from nuclear...
A unified scheme to assign pollen samples vegetation types was used reconstruct patterns north of 55°N at the last glacial maximum (LGM) and mid‐Holocene (6000 years B.P.). The data set assembled for this purpose represents a comprehensive compilation based on work many projects research groups. Five tundra (cushion forb tundra, graminoid prostrate dwarf‐shrub erect low‐ high‐shrub tundra) were distinguished mapped basis modern surface samples. tundra‐forest boundary distributions boreal...
Macroscopic charcoal analysis of lake sediment stratigraphies is a widely used approach to reconstruct past biomass burning patterns ecosystems. The development fire records often relies on single quantification method in subsample; however, recent studies have shown that additional paleoecological information can be obtained by classifying morphologies. morphologies and diagnostic features yields about fuel sources, type, taphonomy, aid calibrating known historical fires. This enhances...
We present a new 23-site network of white spruce ring-width chronologies near boreal treeline in Old Crow Flats, Yukon Territory, Canada. Most span the last 300 years and some reach mid-16th century. The exhibit coherent growth patterns before 1930s. However, since 1930s, they diverge trend one two contrasting, but well-replicated we call Group 1 2. Over instrumental period (1930–2007) sites were inversely correlated with previous-year July temperatures while 2 positively growth-year June...
Abstract The combined effects of climate warming (i.e., increased storminess, reduced sea ice extent, and rising levels) make low‐lying Arctic coastal regions particularly susceptible to storm surges. Mackenzie Delta, a biologically significant resource‐rich region in northwestern Canada, is vulnerable flooding by To properly manage the consequences for residents, infrastructure, ecosystems, better understanding influence change on surge activity required. Here we use particle size analysis...
Summary 1. Rapid environmental change occurring in high‐latitude regions has the potential to cause extensive thawing of permafrost. Retrogressive thaw slumps are a particularly spectacular form permafrost degradation that can significantly impact lake–water chemistry; however, date, effects on aquatic biota have received little attention. 2. We used diatom‐based palaeolimnological approach featuring paired lake study design examine slumping freshwater ecosystems low Arctic western Canada....
One of the most ominous predictions related to recent climatic warming is that low-lying coastal environments will be inundated by higher sea levels. The threat especially acute in polar regions because reductions extent and duration ice cover increase risk storm surge occurrence. Mackenzie Delta northwest Canada an ecologically significant ecosystem adapted freshwater flooding during spring breakup. Marine surges open-water season, which move saltwater into delta, can have major impacts on...
Climate models project that the northern high latitudes will warm at a rate in excess of global mean. This pose severe problems for Arctic and sub-Arctic infrastructure dependent on maintaining low temperatures structural integrity. is case economically important Tibbitt to Contwoyto Winter Road (TCWR)—the world's busiest heavy haul ice road, spanning 400 km across mostly frozen lakes within Northwest Territories Canada. In this study, future climate scenarios are developed region using...
Abstract Climate‐induced changes in streamflow and biogeochemistry are occurring across the northern circumpolar region but several key unknowns include (a) mechanisms responsible among landscapes permafrost conditions, (b) resilience precariousness of hydrological biogeochemical regimes. Even though it is largest physio‐climatic regions circumpolar, these knowledge gaps acute Taiga Shield. This research aimed to determine if hydrology regimes Shield have been resilient recent climate...
A number of contemporary dendroecological studies from northwestern North America have highlighted a divergence in growth trends during recent decades. These suggest that warmer temperatures are now exceeding the physiological threshold some northern tree species, or perhaps contributing to increased drought stress as current precipitation is insufficient offset increasing water demands under conditions. Here we document additional evidence these diverging Mackenzie Delta region Canada and...
Here we present the first tree-ring series (1850–2003) of stable carbon (δ13C) and oxygen (δ18O) isotope ratios from a high-latitude treeline site in northwestern Canada. Both δ13C δ18O were measured at annual resolution whole-ring α-cellulose three white spruce trees (Picea glauca [Moench] Voss) growing Mackenzie Delta. There is strong positive association between maximum summer temperatures. This relation likely results influence temperature-induced drought stress on stomatal conductance....
We examined dated sediment cores from 14 thermokarst affected lakes in the Mackenzie Delta uplands, NT, Arctic Canada, using a case-control analysis to determine how retrogressive thaw slump development degrading permafrost delivery of mercury (Hg) and organic carbon (OC) lakes. show that sediments with on their shorelines (slump-affected lakes) had higher sedimentation rates lower total Hg (THg), methyl (MeHg), concentrations compared where slumps were absent (reference lakes). There was no...
We present a reconstruction of June–July minimum temperatures since AD 1245 for the Mackenzie Delta region based on 29-site network white spruce ( Picea glauca ) ring-width series. Most but not all trees experienced divergent temperature–growth response, similar to divergence that has affected other across Yukon and Alaska. However, in study began as early 1900 we have documented our methods avoid including signals reconstruction. Calibration/verification testing local temperature data,...
Abstract Tree growth at northern treelines is generally temperature‐limited due to cold and short growing seasons. However, temperature‐induced drought stress was repeatedly reported for certain regions of the boreal forest in northwestern North America, provoked by a significant increase temperature possibly reinforced regime shift pacific decadal oscillation (PDO). The aim this study better understand physiological reactions white spruce, dominant species American forest, PDO shifts using...
Changes in pollen and stomata assemblages sediment cores recovered from tundra foresttundra lakes alpine regions of northeastern British Columbia reflect vegetation inferred climatic change throughout the Holocene. Pollen records are presented two lakes, BC2 located alpinetundra zone Dead Spruce Lake at present elevation subalpine treeline. The indicate that an ephemeral shrub herb assemblage was rapidly replaced by aspen (Populus)-spruce (Picea)-birch (Betula) woodland ~ 10600 cal. yr BP....
Field data, remote sensing, and Inuvialuit knowledge were synthesized to document regional ecological change in the outer Mackenzie Delta explore timing, causes, implications of this phenomenon. In September 1999, a large magnitude storm surge inundated low-lying areas Delta. The was among most intense on record resulted highest water levels ever measured at delta front. Synthesis scientific indicates that flooding during 1999 increased soil salinity caused widespread vegetation death....