A5091185667- Polar Research and Ecology
- Cryospheric studies and observations
- Geology and Paleoclimatology Research
- Climate change and permafrost
- Microbial Community Ecology and Physiology
- Marine and coastal ecosystems
- Indigenous Studies and Ecology
- Atmospheric chemistry and aerosols
- Mercury impact and mitigation studies
- Per- and polyfluoroalkyl substances research
- Peatlands and Wetlands Ecology
- Toxic Organic Pollutants Impact
- Geological Studies and Exploration
- Marine animal studies overview
- Aquatic Ecosystems and Phytoplankton Dynamics
- Atmospheric and Environmental Gas Dynamics
- Geological and Geochemical Analysis
- Heavy Metals in Plants
- Terrorism, Counterterrorism, and Political Violence
- Aquatic Ecosystems and Biodiversity
- Cruise Tourism Development and Management
- Healthcare Systems and Challenges
- Heavy metals in environment
- Arctic and Antarctic ice dynamics
- Smart Materials for Construction
University of Minnesota
2020-2024
University of Minnesota System
2023
The Ohio State University
2010-2021
The Ohio State University at Marion
2015-2020
Byrd Polar and Climate Research Center
2017
University of Alberta
2005-2012
University of Copenhagen
2007
Max Planck Institute for Evolutionary Anthropology
2007
Trent University
2007
University of York
2007
It is difficult to obtain fossil data from the 10% of Earth's terrestrial surface that covered by thick glaciers and ice sheets, hence, knowledge paleoenvironments these regions has remained limited. We show DNA amino acids buried organisms can be recovered basal sections deep cores, enabling reconstructions past flora fauna. high-altitude southern Greenland, currently lying below more than 2 kilometers ice, was inhabited a diverse array conifer trees insects within million years. The...
Significance Trace elements are integral to biogeochemical processes at the Earth’s surface and play an important role in carbon cycle as micronutrients support biological productivity. We present data from Greenland Antarctic ice sheets demonstrate importance of subglacial mobilizing substantial quantities these elements. Usually immobile found meltwaters elevated concentrations compared with typical rivers, most exhibiting distinctive size fractionation due adsorption onto nanoparticles....
Abstract The Subglacial Antarctic Lakes Scientific Access (SALSA) Project accessed Mercer Lake using environmentally clean hot-water drilling to examine interactions among ice, water, sediment, rock, microbes and carbon reservoirs within the lake water column underlying sediments. A ~0.4 m diameter borehole was melted through 1087 of ice maintained over ~10 days, allowing observation properties collection sediment with various tools. Over this period, SALSA collected: 60 L 10 deep water;...
We identified some of the sources and sinks monomethyl mercury (MMHg) inorganic (HgII) on Ellesmere Island in Canadian High Arctic. Atmospheric Hg depletion events resulted deposition Hg(II) into upper layers snowpacks, where concentrations total (all forms Hg) reached over 20 ng/L. However, our data suggest that much this deposited was rapidly photoreduced to Hg(0) which then evaded back atmosphere. As a result, we estimate net wet dry during winter lower at sites (0.4−5.9 mg/ha) than more...
We sampled seawater and snowpacks in the Canadian high Arctic for methylated species of mercury (Hg). discovered that, although under sea ice had very low concentrations total Hg (THg, all forms a sample; on average 0.14−0.24 ng L-1), 30−45% THg was monomethyl (MMHg) form (on 0.057−0.095 making itself direct source MMHg biomagnification through marine food webs. Seawater also contained gaseous elemental (GEM; 129 ± 36 pg suggesting that open water regions such as polynyas leads were net ∼130...
Abstract Aquatic dissolved organic matter (DOM) is a major reservoir of reduced carbon and has significant influence on heterotrophic biological productivity water quality in marine freshwater environments. Although the forms transformations DOM temperate aquatic soil environments have been studied extensively, this not case for glacial In study, fluorescent excitation–emission matrices (EEMs), parallel factor analysis (PARAFAC) cluster were used to characterize fluorescing components ice...
Because few ice core records from the Himalayas exist, understanding of onset and timing human impact on atmosphere “roof world” remains poorly constrained. We report a continuous 500-y trace metal record Dasuopu glacier (7,200 m, central Himalayas), highest drilling site Earth. show that an early contamination toxic metals, particularly Cd, Cr, Mo, Ni, Sb, Zn, emerged at high elevation in European Industrial Revolution (∼1780 AD). This was amplified by intensification snow accumulation...
Ice streams that flow into Ross Shelf are underlain by water-saturated sediments, a dynamic hydrological system, and subglacial lakes intermittently discharge water downstream across grounding zones of West Antarctic Sheet (WAIS). A 2.06 m composite sediment profile was recently recovered from Mercer Subglacial Lake, 15 deep cavity beneath 1087 thick portion the Stream. We examined microbial abundances, used 16S rRNA gene amplicon sequencing to assess community structures, characterized...
Abstract The molecular characteristics of dissolved organic matter (DOM) reflect both its source material and biogeochemical history. In glacial systems, DOM might be expected to change over the course a melt season as changes in glacier drainage system cause mobilization from different OM pools. To test this hypothesis we used Principal Components Analysis (PCA) synchronous fluorescence spectra detect describe meltwater Coast Mountains northern British Columbia, Canada. For most season,...
Tundra ecosystems store vast amounts of soil organic carbon, which may be sensitive to climatic change. Net ecosystem production, NEP, is the net exchange carbon dioxide (CO2) between landscapes and atmosphere, represents balance CO2 uptake by photosynthesis release decomposition autotrophic respiration. Here we examine across seven sites in Canadian low high Arctic during peak growing season (July) summer 2008. All were sinks for atmospheric (NEP ranged from 5 67 g C m–2), with being...
The biogeochemical cycling of organic carbon (OC) has important implications for aquatic system ecology because the abundance and molecular characteristics OC influence contaminant transport bioavailability, determine its suitability as a substrate microbial metabolism. There have been few studies in glacier systems questions remain regarding abundance, provenance, transformations these environments. To address questions, fluorescence dissolved (DOC) were investigated at John Evans Glacier...
The sources of methylmercury (MeHg; the toxic form mercury that is biomagnified through foodwebs) to Arctic freshwater organisms have not been clearly identified. We used a mass balance approach quantify MeHg production in two wetland ponds Lake Hazen region northern Ellesmere Island, NU, Canadian High and evaluate importance these systems as foodwebs. show internal (1.8-40 ng m(-2) d(-1)) much larger source than external inputs from direct atmospheric deposition (0.029-0.051 d(-1)),...
Cold-based polar glacier watersheds contain well-defined supraglacial, ice-marginal, and proglacial elements that differ in their degree of hydrologic connectivity, sources water (e.g., snow, ice, and/or sediment pore water), meltwater residence times, allochthonous autochthonous nutrient, loads. We investigated 11 distinct hydrological units along the ice marginal, flow paths drain Joyce Glacier McMurdo Dry Valleys Antarctica. found these play unique important roles as sinks for dissolved...
Abstract High Arctic landscapes are expansive and changing rapidly. However, our understanding of their functional responses potential to mitigate or enhance anthropogenic climate change is limited by few measurements. We collected eddy covariance measurements quantify the net ecosystem exchange ( NEE ) CO 2 with polar semidesert meadow wetland at highest latitude location measured date (82°N). coupled these rare data ground satellite vegetation production (Normalized Difference Vegetation...
Dissolved organic matter (DOM) exported in glacier meltwater influences downstream biogeochemical processes, and climate warming may increase the DOM flux. In this study, we quantify use fluorescence spectroscopy parallel factor analysis (PARAFAC) to characterize Taylor Wright Valleys, McMurdo Dry Antarctica.Andersen Creek, a proglacial stream draining Canada Glacier meltwater, ∼20 kg of as dissolved carbon (DOC) Lake Hoare during melt season. Supraglacial snowpack from all Valley glaciers...
Abstract. Himalayan glaciers are melting due to atmospheric warming, with the potential limit access water for more than 25 % of global population that resides in these glacier meltwater catchments. Black carbon has been implicated as a factor is contributing melt, but its sources and mechanisms delivery Himalayas remain controversial. Here, we provide 211-year ice core record spanning 1781–1992 CE refractory black (rBC) deposition from Dasuopu date provided highest-elevation (7200 m). We...
Abstract Dissolved organic matter (DOM) is an important component of aquatic carbon and nutrient budgets a metabolic substrate for organisms at the base food chains. Active microbial communities in glaciers affect abundance characteristics (OM) that exported to downstream ecosystems. However, how OM biogeochemically altered remains unknown studies documenting active activity by detecting situ biogeochemical modifications are lacking due difficulties characterizing low concentrations DOM...
This short summary presents selected results of an ongoing investigation into the feedbacks that contribute to amplified Arctic warming. The consequences warming for biodiversity and landscape response global warmth are currently being interpreted. North American records large-scale paleoenvironmental change during Pliocene exquisitely preserved locked in permafrost, providing opportunity faunal reconstruction with unprecedented quality resolution. During a period mean temperatures only...
Glaciers overrun organic matter (OM) during periods of advance, making this OM available as a metabolic substrate for subglacial microbes. The biogeochemical fate remains poorly understood, ultimately limiting our understanding cycling, particularly cold-based glaciers. This study presents evidence the transformation algal mat material that was by glacier (Suess Glacier, Taylor Valley, Antarctica) its advance 4840–3570 years BP. We use suite stable isotope analyses to show active nitrogen...
Abstract. Ice formed in the subglacial environment can contain some of highest concentrations solutes, nutrients, and microbes found glacier systems, which be released to downstream freshwater marine ecosystems forefields. Despite potential ecological importance basal ice, our understanding its spatial temporal biogeochemical variability remains limited. We hypothesize that thermal regime glaciers is a dominant control on biogeochemistry because it influences degree mobilize material from...
Abstract This paper discusses recent developments in the domain of Geoscience, which contribute to better 3D modelling hydrocarbon fields. These techniques integrate geophysical, geological and reservoir engineering knowledge construction a earth model. The 3D-earth model brings consistency between views held by different subsurface disciplines. A common quantitative description is used for all calculations interpretation studies. Starting with picked horizons well data, number aspects are...