A5031184621- Cryospheric studies and observations
- Climate change and permafrost
- Winter Sports Injuries and Performance
- Landslides and related hazards
- Arctic and Antarctic ice dynamics
- Polar Research and Ecology
- Geology and Paleoclimatology Research
- Methane Hydrates and Related Phenomena
- Atmospheric and Environmental Gas Dynamics
- Geological Studies and Exploration
- Climate variability and models
- Geomagnetism and Paleomagnetism Studies
- Geophysics and Gravity Measurements
- Spaceflight effects on biology
- Planetary Science and Exploration
- Hydrocarbon exploration and reservoir analysis
- Biocrusts and Microbial Ecology
- Opportunistic and Delay-Tolerant Networks
- Hydrology and Watershed Management Studies
- Per- and polyfluoroalkyl substances research
- Light effects on plants
- Clinical Nutrition and Gastroenterology
- Statistical and Computational Modeling
- Minerals Flotation and Separation Techniques
- Cancer therapeutics and mechanisms
University of Fribourg
2020-2025
University of Lausanne
2025
University of Bristol
2016-2024
At Bristol
2022
University of Edinburgh
2013-2017
University of Nottingham
2016
Scientific Committee on Antarctic Research
2012
University of Cambridge
2012
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...
The Greenland Ice Sheet (GrIS) has been losing mass at an accelerating rate since the mid-1990s. This due to both increased ice discharge into ocean and melting surface, with latter being dominant contribution. change in state attributed rising temperatures a decrease surface albedo. We show, using satellite data climate model output, that abrupt reduction balance about 1995 can be largely coincident trend of decreasing summer cloud cover enhancing melt-albedo feedback. Satellite...
Abstract The freshwater budget of the Arctic and sub‐polar North Atlantic Oceans has been changing due, primarily, to increased river runoff, declining sea ice enhanced melting land ice. Since mid‐1990s this latter component experienced a pronounced increase. We use combination satellite observations glacier flow speed regional climate modeling reconstruct flux from Greenland sheet glaciers caps for period 1958–2016. cumulative anomaly exceeded 6,300 ± 316 km 3 by 2016. This is roughly twice...
Abstract We present ice velocities from a land‐terminating transect extending >115 km into the western Greenland Ice Sheet during three contrasting melt years (2009–2011) to determine whether enhanced melting accelerates dynamic mass loss. find no significant correlation between surface and annual flow. There is however positive summer displacement, but negative with winter displacement. This response consistent hydro‐dynamic coupling; flow results longer periods of increasing greater...
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...
Abstract. Melting of the Greenland Ice Sheet (GrIS) is largest single contributor to eustatic sea level and amplified by growth pigmented algae on ice surface, which increases solar radiation absorption. This biological albedo-reducing effect its impact upon rise has not previously been quantified. Here, we combine field spectroscopy with a radiative-transfer model, supervised classification unmanned aerial vehicle (UAV) satellite remote-sensing data, runoff modelling calculate biologically...
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...
Future climate projections show a marked increase in Greenland Ice Sheet (GrIS) runoff during the 21
Blooms of Zygnematophycean “glacier algae” lower the bare ice albedo Greenland Ice Sheet (GrIS), amplifying summer energy absorption at surface and enhancing meltwater runoff from largest cryospheric contributor to contemporary sea-level rise. Here, we provide a step change in current understanding algal-driven sheet darkening through quantification photophysiological mechanisms that allow glacier algae thrive on darken surface. Significant secondary phenolic pigmentation (11 times cellular...
Significance During summer, meltwater generated on the Greenland ice sheet surface accesses bed, lubricating basal motion and resulting in periods of faster flow. However, net impact varying volumes upon seasonal annual flow, thus sea level rise, remains unclear. In 2012, despite record runoff, including two extreme melt events, at a land-terminating margin flowed more slowly than average year 2009, due principally to slower winter flow following summer Our findings suggest that margins...
Abstract Melting of the Greenland Ice Sheet is a leading cause land-ice mass loss and cryosphere-attributed sea level rise. Blooms pigmented glacier ice algae lower albedo accelerate surface melting in sheet’s southwest sector. Although up to 13% this region, controls on bloom development remain poorly understood. Here we show direct link between mineral phosphorus biomass through quantification solid fluid phase reservoirs habitats across ablation zone sheet. We demonstrate that nutrients...
<strong class="journal-contentHeaderColor">Abstract.</strong> The darkening effects of biological impurities on ice and snow have been recognised as a control the surface energy balance terrestrial snow, sea ice, glaciers sheets. With heightened interest in understanding impacts changing climate processes, quantifying impact albedo (<q>bioalbedo</q>) its evolution through time is rapidly growing field research. However, rigorous quantification bioalbedo has remained elusive because...
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...
It is fundamental to understand the development of Zygnematophycean (Streptophyte) micro-algal blooms within Greenland Ice Sheet (GrIS) supraglacial environments, given their potential significantly impact both physical (melt) and chemical (carbon nutrient cycling) surface characteristics. Here, we report on a space-for-time assessment GrIS ice algal bloom, achieved by sampling an ∼85 km transect spanning south-western bare zone during 2016 ablation season. Cell abundances ranged from 0 1.6...
Abstract. Runoff from the Greenland Ice Sheet (GrIS) has increased in recent years due largely to changes atmospheric circulation and warming. Albedo reductions resulting these have amplified surface melting. Some of largest declines GrIS albedo occurred ablation zone south-west sector are associated with development dark ice surfaces. Field observations at local scales reveal that a variety light-absorbing impurities (LAIs) can be present on surface, ranging inorganic particulates...
Basal sliding is a main control on glacier flow primarily driven by water pressure at the base. The ongoing increase in surface melting of Greenland Ice Sheet warrants an examination its impact basal and turn sliding. Here we examine case Russell Glacier, West Greenland, where extensive set observations has been collected. These suggest that recent melt had equivocal annual velocity, with stable lower part drainage basin but accelerated above Equilibrium Line Altitude (ELA). distinct...
The cumulative Greenland freshwater flux anomaly has exceeded 5,000 km3 since the 1990s. volume of this surplus is expected to cause substantial freshening in North Atlantic. Analysis hydrographic observations subpolar seas reveals signals 2010s. sources are yet be determined. In study, relationship between and tested by analyzing propagation its impact on salinity Atlantic based observational data numerical experiments with without runoff. A passive tracer continuously released during...
Abstract. One of the primary controls upon melting Greenland Ice Sheet (GrIS) is albedo, a measure how much solar radiation that hits surface reflected without being absorbed. Lower-albedo snow and ice surfaces therefore warm more quickly. There major difference in albedo snow-covered versus bare-ice surfaces, but observations also show there substantial spatio-temporal variability up to ∼0.4 albedo. Variability has been attributed number processes including accumulation light-absorbing...
Abstract We use airborne accumulation radar data acquired over the Greenland Ice Sheet between 2002 and 2018 to identify changes in ice slab extent thickness. show that slabs several meters thick were already present at least as early 2002. Between 2012 2018, they expanded by 13,400–17,600 inland, or 37%–44%. Our results document extremely warm summer of produced near‐surface layers higher elevations, enabling develop with only moderate melting following summers. With repeat flights along a...