A5070109310- Cryospheric studies and observations
- Geology and Paleoclimatology Research
- Polar Research and Ecology
- Climate change and permafrost
- Methane Hydrates and Related Phenomena
- Microbial Community Ecology and Physiology
- Marine and coastal ecosystems
- Winter Sports Injuries and Performance
- Geochemistry and Elemental Analysis
- Arctic and Antarctic ice dynamics
- Silicon Effects in Agriculture
- Paleontology and Stratigraphy of Fossils
- Geomagnetism and Paleomagnetism Studies
- Pleistocene-Era Hominins and Archaeology
- Atmospheric and Environmental Gas Dynamics
- Mercury impact and mitigation studies
- Per- and polyfluoroalkyl substances research
- Planetary Science and Exploration
- Analytical Chemistry and Sensors
- Geophysics and Gravity Measurements
- Landslides and related hazards
- Geological Studies and Exploration
- Smart Materials for Construction
- Marine Biology and Ecology Research
- Atmospheric chemistry and aerosols
UiT The Arctic University of Norway
2024-2025
University of Pennsylvania
2021-2025
Ministry of Earth Sciences
2024
California University of Pennsylvania
2022-2023
Florida State University
2018-2022
National High Magnetic Field Laboratory
2018-2022
University of Bristol
2010-2021
GFZ Helmholtz Centre for Geosciences
2018-2021
Cabot (United States)
2015
The Greenland and Antarctic Ice Sheets cover ~ 10% of global land surface, but are rarely considered as active components the iron cycle. ocean waters around both ice sheets harbour highly productive coastal ecosystems, many which limited. Measurements concentrations in subglacial runoff from a large Sheet catchment reveal potential for globally significant export labile fractions to near-coastal euphotic zone. We estimate that flux bioavailable associated with glacial is 0.40-2.54 Tg per...
Abstract. The element silicon (Si) is required for the growth of silicified organisms in marine environments, such as diatoms. These consume vast amounts Si together with N, P, and C, connecting biogeochemical cycles these elements. Thus, understanding cycle ocean critical wider issues carbon sequestration by ocean's biological pump. In this review, we show that recent advances process studies indicate total inputs outputs, to from world ocean, are 57 % 37 higher, respectively, than previous...
Abstract. Sunlight penetrates the bare-ice surface of glaciers and ice sheets, giving rise to presence a three-dimensional porous matrix partially melted crystals known as weathering crust. Surface meltwater slowly percolates through this crust, which hosts active diverse bacterial communities, until it reaches supraglacial stream. Despite potential implications crust dynamics for glacial melting export carbon nutrients downstream ecosystems, its role in biogeochemical cycling remains...
Abstract The contribution of ice sheets to the global biogeochemical cycle phosphorus is largely unknown, due lack field data. Here we present first comprehensive study export from two Greenland Ice Sheet glaciers. Our results indicate that sheet a hot spot in Arctic. Soluble reactive (SRP) concentrations, up 0.35 µ M , are similar those observed Arctic rivers. Yields SRP among highest literature, with denudation rates 17–27 kg P km −2 yr −1 . Particulate phases, as nonglaciated catchments,...
Abstract Ice sheets play a more important role in the global silicon cycle than previously appreciated. Input of dissolved and amorphous particulate silica into natural waters stimulates growth diatoms. Here we measure Greenland Sheet meltwaters icebergs, demonstrating potential for high ice sheet export. Our flux is 0.20 (0.06–0.79) Tmol year −1 , ∼50% input from Arctic rivers. Amorphous comprises >95% this highly soluble sea water, as indicated by significant increase across fjord...
Glacial meltwater runoff is likely an important source of limiting nutrients for downstream primary producers.This has particular significance regions surrounding the Greenland Ice Sheet, which discharges >400 km 3 annually.The Arctic warming rapidly but impact higher discharge on nutrient export unknown.We present four years hydrological and geochemical data from a large Sheet catchment that includes two highest melt record (2010, 2012).Measurements reveal significant variation in dissolved...
Abstract. Iceberg-hosted sediments and atmospheric dust transport potentially bioavailable iron to the Arctic Southern oceans as ferrihydrite. Ferrihydrite is nanoparticulate more soluble, well bioavailable, than other (oxyhydr)oxide minerals (lepidocrocite, goethite, hematite). A suite of 50 iceberg-hosted contain a mean content 0.076 wt % Fe ferrihydrite, which produces fluxes ranging from 0.7 5.5 3.2 25 Gmoles yr−1 respectively. Atmospheric (with little or no combustion products) contains...
Abstract. Fjord and continental shelf environments in the polar regions are host to some of planet's most productive ecosystems support economically important fisheries. Their productivity, however, is often critically dependent upon nutrient supply from upstream terrestrial delivered via river systems. In glacially fed coastal ecosystems, riverine nutrients largely sourced melting snow ice. The largest extensive ecosystem Arctic that bordering Greenland Ice Sheet. future primary...
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 Physical erosion and chemical weathering rates beneath glaciers are expected to increase in a warming climate with enhanced melting but poorly constrained. We present global dataset of cations meltwaters 77 glaciers, including new data from 19 Asian glaciers. Our study shows that contemporary cation denudation (CDRs) (2174 ± 977 Σ*meq + m − 2 year 1 ) ~3 times higher than two decades ago, up 10 ice sheet catchments (~150-2000 ), 50 whole means (~30-45 ~4 major non-glacial riverine...
Glaciers and ice sheets are a significant source of nanoparticulate Fe, which is potentially important in sustaining the high productivity observed near-coastal regions proximal to terrestrial cover. However, bioavailability particulate iron poorly understood, despite its importance ocean Fe inventory. We combined high-resolution imaging spectroscopy investigate abundance, morphology valence state glacial sediments. Our results document widespread occurrence amorphous Fe(II)-rich...
A more insightful view of iron in glacial systems requires consideration speciation and mineralogy, the potential for minerals to undergo weathering ice-water environments, impact freezing on concentration speciation, delivery alteration during transport into ocean. size fractionation approach improves recognition by separating dissolved Fe (0.1 wt. %) which represent samples on-going transformation ferrihydrite goethite/hematite is incomplete. Numerical models subglacial show that nanomolar...
Abstract The Greenland Ice Sheet is currently not accounted for in Arctic mercury budgets, despite large and increasing annual runoff to the ocean socio-economic concerns of high levels organisms. Here we present concentrations meltwaters from three glacial catchments on southwestern margin evaluate export downstream fjords based samples collected during summer ablation seasons. We show that dissolved are among highest recorded natural waters yields these (521–3,300 mmol km −2 year −1 ) two...
Abstract Glaciers and ice sheets cover over 10 % of Earth's land surface area store a globally significant amount dissolved organic matter (DOM), which is highly bioavailable when exported to proglacial environments. Recent rapid glacier mass loss hypothesized have increased fluxes DOM from these environments, yet the molecular composition glacially derived has only been studied for handful glaciers. We determine using ultrahigh resolution spectrometry diverse suite Arctic glacial including...
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 Projections of Antarctica's contribution to future sea level rise are associated with significant uncertainty, in part because the observational record is too short capture long‐term processes necessary estimate ice mass changes over societally relevant timescales. Records grounding line retreat from geologic past offer an opportunity extend our observations these beyond modern and gain a more comprehensive understanding ice‐sheet change. Here, we present constraints on timing...
Microorganisms are flushed from the Greenland Ice Sheet (GrIS) where they may contribute towards nutrient cycling and community compositions of downstream ecosystems. We investigate meltwater microbial assemblages as exit GrIS a large outlet glacier, enter river delta during record melt year 2012. Prokaryotic abundance, flux composition was studied, factors affecting structures were statistically considered. The mean concentration cells exiting ice sheet 8.30 × 104 mL-1 we estimate that...
Abstract The Greenland Ice Sheet is losing mass at a remarkable rate as result of climatic warming. This loss coincides with the export dissolved organic matter (DOM) in glacial meltwaters. However, little known about how source and composition exported DOM changes over melt season, which key for understanding its fate downstream ecosystems. Over 2015 ablation we sampled outflow Leverett Glacier, large land‐terminating glacier Sheet. Dissolved carbon (DOC) concentrations fluorescence were...
There is current debate about whether the balance of photosynthesis and respiration has any impact on net accumulation organic matter glacier surfaces. This study assesses controls rates ecosystem production (NEP), respiration, in cryoconite holes during main melt season (June–August 2009) three valley glaciers Svalbard. Cryoconite thickness content explained 87% total variation (in units volume), (but not sediment depth) was a significant ( p < 0.05) control (by volume). The average...
The seasonal melting of ice entombed cryoconite holes on McMurdo Dry Valley glaciers provides oases for life in the harsh environmental conditions polar desert where surface air temperatures only occasionally exceed 0°C during Austral summer. Here we follow temporal changes hole biogeochemistry Canada Glacier from fully frozen through initial stages spring thaw towards melted holes. had a mean isolation age glacial drainage system 3.4 years, with an increasing mass aqueous nutrients...