A5036057208- Climate change and permafrost
- Cryospheric studies and observations
- Methane Hydrates and Related Phenomena
- Arctic and Antarctic ice dynamics
- Atmospheric and Environmental Gas Dynamics
- Marine and coastal ecosystems
- Geology and Paleoclimatology Research
- Peatlands and Wetlands Ecology
- Soil and Water Nutrient Dynamics
- Geological Studies and Exploration
- Microbial Community Ecology and Physiology
- Fire effects on ecosystems
- Groundwater and Isotope Geochemistry
- Mercury impact and mitigation studies
- Indigenous Studies and Ecology
- Hydrocarbon exploration and reservoir analysis
- Coastal wetland ecosystem dynamics
- Hydrology and Watershed Management Studies
- Marine Biology and Ecology Research
- Environmental DNA in Biodiversity Studies
- Isotope Analysis in Ecology
- Fish Ecology and Management Studies
- Marine and coastal plant biology
- Polar Research and Ecology
- Aquatic Ecosystems and Phytoplankton Dynamics
University of Alberta
2016-2025
Hakai Institute
2020-2023
University of Alaska Southeast
2023
Tula Foundation
2017-2022
Veer Narmad South Gujarat University
2017
Marine Biological Laboratory
2011-2012
York University
2012
Simon Fraser University
2005-2011
Fisheries and Oceans Canada
2005
Trent University
2005
Abstract. The Arctic is a water-rich region, with freshwater systems covering about 16 % of the northern permafrost landscape. Permafrost thaw creates new ecosystems, while at same time modifying existing lakes, streams, and rivers that are impacted by thaw. Here, we describe current state knowledge regarding how affects lentic (still) lotic (moving) systems, exploring effects both thermokarst (thawing collapse ice-rich permafrost) deepening active layer (the surface soil thaws refreezes...
As the permafrost region warms, its large organic carbon pool will be increasingly vulnerable to decomposition, combustion, and hydrologic export. Models predict that some portion of this release offset by increased production Arctic boreal biomass; however, lack robust estimates net balance increases risk further overshooting international emissions targets. Precise empirical or model-based assessments critical factors driving are unlikely in near future, so address gap, we present from 98...
Abstract Northern rivers connect a land area of approximately 20.5 million km 2 to the Arctic Ocean and surrounding seas. These account for ~10% global river discharge transport massive quantities dissolved particulate materials that reflect watershed sources impact biogeochemical cycling in ocean. In this paper, multiyear data sets from coordinated sampling program are used characterize organic carbon (POC) nitrogen (PN) export six largest within pan‐Arctic (Yenisey, Lena, Ob', Mackenzie,...
Abstract. As Arctic regions warm and frozen soils thaw, the large organic carbon pool stored in permafrost becomes increasingly vulnerable to decomposition or transport. The transfer of newly mobilized atmosphere its potential influence upon climate change will largely depend on degradability delivered aquatic ecosystems. Dissolved (DOC) is a key regulator metabolism, yet knowledge mechanistic controls DOC biodegradability currently poor due scarcity long-term data sets, limited spatial...
Riverine exports of organic and inorganic carbon (OC, IC) to oceans are intricately linked processes occurring on land. Across high latitudes, thawing permafrost, alteration hydrologic flow paths, changes in vegetation may all affect this flux, with subsequent implications for regional global (C) budgets. Using a unique, multi-decadal dataset continuous discharge coupled water chemistry measurements the Mackenzie River, we show major increases dissolved OC (DOC) IC (as alkalinity) fluxes...
Research has traditionally focused on atmospheric release of carbon from thawing permafrost, yet overlooked waterborne pathways likely contribute significantly, especially in a warming Arctic. To address this knowledge gap and better constrain the fate North, we recommend inter-disciplinary efforts bridging physical, chemical computational research. As climate change thaws Arctic's foundations, new subterranean waterways form threaten to wash away decompose once locked permafrost. In...
A series of seasonally distributed measurements from the six largest Arctic rivers (the Ob', Yenisey, Lena, Kolyma, Yukon and Mackenzie) was used to examine magnitude significance riverine DIC flux larger scale C dynamics within system. concentration showed considerable, synchronous, seasonal variation across these large rivers, which have an estimated combined annual 30 Tg yr −1 . By examining relationship between landscape variables known regulate DIC, we extrapolate a 57 ± 9.9 for full...
Climate change is causing extensive warming across arctic regions resulting in permafrost degradation, alterations to regional hydrology, and shifting amounts composition of dissolved organic matter (DOM) transported by streams rivers. Here, we characterize the DOM optical properties six largest rivers draining into Arctic Ocean examine ability measurements provide meaningful insights terrigenous carbon export patterns biogeochemical cycling. The chemical aquatic varied with season, spring...
Abstract Understanding what controls the lateral flux of organic and inorganic carbon from landscapes to surface waters is key fully understanding terrestrial ecosystem balances, biogeochemistry freshwaters, how hydrologically‐mediated movement between these ecosystems may be altered by global change. In this paper, we synthesize current knowledge identify major gaps in our land‐to‐water fluxes dissolved particulate carbon, CO 2 , bicarbonate exploring: (1) variations soil stocks affect...
While much of the dissolved organic carbon (DOC) within rivers is destined for mineralization to CO 2 , a substantial fraction riverine bicarbonate (HCO 3 − ) flux represents sink, as result weathering processes that sequester HCO . We explored landscape‐level controls on DOC and in subcatchments boreal, with specific focus effect permafrost C flux. To do this, we undertook multivariate analysis partitioned variance attributable known, key regulators (runoff, lithology, vegetation) prior...
Riverine carbonate alkalinity (HCO3- and CO32-) sourced from chemical weathering represents a significant sink for atmospheric CO2. Alkalinity flux Arctic rivers is partly determined by precipitation, permafrost extent, groundwater flow paths, surface vegetation, all of which are changing under warming climate. Here we show that over the past three half decades, export Yenisei Ob' Rivers increased 225 to 642 Geq yr-1 (+185%) 201 470 (+134%); an average rate 11.90 7.28 yr-1, respectively....
Abstract Permafrost thaw has been widely observed to alter the biogeochemistry of recipient aquatic ecosystems. However, research from various regions shown considerable variation in effect. In this paper, we propose a state factor approach predict release and transport materials permafrost through networks. Inspired by Hans Jenny's seminal description soil‐forming factors, based on growing body subject, that series factors—including relief, ice content, extent, parent material—will...
Abstract. Methane emissions from boreal and arctic wetlands, lakes, rivers are expected to increase in response warming associated permafrost thaw. However, the lack of appropriate land cover datasets for scaling field-measured methane circumpolar scales has contributed a large uncertainty our understanding present-day future emissions. Here we present Boreal–Arctic Wetland Lake Dataset (BAWLD), dataset based on an expert assessment, extrapolated using random forest modelling available...
Abstract The magnitude of future emissions greenhouse gases from the northern permafrost region depends crucially on mineralization soil organic carbon (SOC) that has accumulated over millennia in these perennially frozen soils. Many recent studies have used radiocarbon ( 14 C) to quantify release this “old” SOC as CO 2 or CH 4 atmosphere dissolved and particulate (DOC POC) surface waters. We compiled ~1,900 C measurements 51 sites assess vulnerability thawing tundra, forest, peatland, lake,...
Abstract. The intensification of thaw-driven mass wasting is transforming glacially conditioned permafrost terrain, coupling slopes with aquatic systems, and triggering a cascade downstream effects. Within the context recent, rapidly evolving climate controls on geomorphology we (A) quantify three-dimensional retrogressive thaw slump enlargement describe processes thresholds to (B) investigate catchment-scale patterns slope thermokarst impacts geomorphic implications, (C) map propagation...
Land–ocean linkages are strong across the circumpolar north, where Arctic Ocean accounts for 1% of global ocean volume and receives more than 10% river discharge. Yet estimates riverine mercury (Hg) export constrained from direct Hg measurements remain sparse. Here, we report results a coordinated, year-round sampling program that focused on six major rivers to establish contemporary (2012–2017) benchmark export. We determine exported an average 20 000 kg y–1 total (THg, all forms Hg)....
Abstract Climate change is dramatically altering Arctic ecosystems, leading to shifts in the sources, composition, and eventual fate of riverine dissolved organic matter (DOM) Ocean. Here we examine a 6‐year DOM compositional record from six major rivers using Fourier‐transform ion cyclotron resonance mass spectrometry paired with carbon isotope data (Δ 14 C, δ 13 C) investigate how seasonality permafrost influence DOM, export may warming. Across pan‐Arctic, molecular composition...
In contrast to fairly good knowledge of dissolved carbon and major elements in great Arctic rivers, seasonally resolved concentrations many trace remain poorly characterized, hindering assessment the current status possible future changes hydrochemistry Eurasian Arctic. To fill this gap, here we present results for a broad suite largest rivers Russian (Ob, Yenisey, Lena, Kolyma). For context, also that are more routinely measured these rivers. Water samples study were collected during an...
Although the Arctic Ocean is most riverine-influenced of all world's oceans, importance terrigenous nutrients in this environment poorly understood. This study couples estimates circumpolar riverine nutrient fluxes from PARTNERS (Pan-Arctic River Transport Nutrients, Organic Matter, and Suspended Sediments) Project with a regionally configured version MIT general circulation model to develop distribution availability dissolved N Ocean, assess its for primary production, compare these...
Lakes of the Mackenzie Delta occur across a gradient that contains three clear end members: those remain connected to river‐water channels throughout summer; receive only brief inputs river water during an annual spring flood but contain dense macrophyte stands; and experience significant permafrost thaw along their margins. We measured dissolved organic carbon (DOC) concentration, matter (DOM) absorption fluorescence, stable isotopes DOM, DOM precursor materials, bacteria elucidate...
Retrogressive thaw slumps (RTSs) are thermokarst features created by the rapid of ice-rich permafrost, and can mobilize vast quantities sediments solutes downstream. However, effect slumping on downstream concentrations yields total mercury (THg) methylmercury (MeHg) is unknown. Fluvial THg MeHg RTSs Peel Plateau (Northwest Territories, Canada) were up to 2 orders magnitude higher than upstream, reaching 1,270 ng L–1 7 L–1, respectively, highest ever measured in uncontaminated sites Canada....
Abstract. Boreal peatlands are major catchment sources of dissolved organic carbon (DOC) and nutrients thus strongly regulate the landscape balance, aquatic food webs, downstream water quality. Climate change is likely to influence solute yield directly through climatic controls on run-off generation, but also indirectly altered disturbance regimes. In this study we monitored chemistry from early spring until fall at outlets a 321 km2 that burned 3 years prior 134 undisturbed catchment. Both...