A5038296219- Cryospheric studies and observations
- Geology and Paleoclimatology Research
- Polar Research and Ecology
- Silicon Effects in Agriculture
- Geochemistry and Elemental Analysis
- Methane Hydrates and Related Phenomena
- Winter Sports Injuries and Performance
- Geomagnetism and Paleomagnetism Studies
- Microbial Community Ecology and Physiology
- Pleistocene-Era Hominins and Archaeology
- Climate change and permafrost
- Mercury impact and mitigation studies
- Atmospheric and Environmental Gas Dynamics
- Marine and coastal ecosystems
- Planetary Science and Exploration
- Diatoms and Algae Research
- Paleontology and Stratigraphy of Fossils
- Arsenic contamination and mitigation
- Arctic and Antarctic ice dynamics
- Indigenous Studies and Ecology
- Geophysics and Gravity Measurements
- Adventure Sports and Sensation Seeking
- Modular Robots and Swarm Intelligence
- Marine animal studies overview
- Groundwater and Isotope Geochemistry
University of Bristol
2018-2025
Charles University
2021-2025
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 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 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...
Abstract Subglacial weathering releases biologically important nutrients into meltwaters that have the potential to influence downstream ecosystems. There is a need understand how accelerated glacial retreat could impact biogeochemical cycling in coastal regions near future. However, fjords—important gateways connecting Greenland ice sheet and oceans—are highly heterogeneous environments both space time. Here, we investigate temporal variability of nutrient dynamics glacier‐fed fjord (Nuup...
Abstract Globally averaged riverine silicon (Si) concentrations and isotope composition (δ 30 Si) may be affected by the expansion retreat of large ice sheets during glacial−interglacial cycles. Here we provide evidence this based on δ Si meltwater runoff from a Greenland Ice Sheet catchment. Glacier has lightest measured in running waters (−0.25 ± 0.12‰), significantly lower than nonglacial rivers (1.25 0.68‰), such that overall decline glacial since Last Glacial Maximum (LGM) explain...
Meltwater streams connect the glacial cryosphere with downstream ecosystems. Dissolved and particulate matter exported from ecosystems originates contrasting supraglacial subglacial environments, microbial cells have potential to serve as ecological hydrological indicators for ecosystem processes. Here, we compare assemblages meltwater of 24 glaciers six (sub)Arctic regions - southwestern Greenland Ice Sheet, Qeqertarsuaq (Disko Island) in west Greenland, Iceland, Svalbard, western Norway,...
Silicate weathering is a dominant control on the natural carbon cycle. The supply of rock (e.g. via mountain uplift) has been proposed as key control, and suggested primary cause Cenozoic cooling. However, this ambiguous because lack definitive tracers. We use isotopes major cations directly involved in silicate cycle: magnesium, silicon calcium. Here we examine these isotope systems rivers draining catchments with variable uplift rates (used proxy for exposure rates) from South Island, New...
Chemical weathering dynamics in Greenland Ice Sheet (GrIS) catchments are largely unknown, due to a scarcity of field data. This paper presents the most comprehensive study date chemical rates from four GrIS contrasting size. Cationic denudation varied greatly between studied (2.6 37.6 tons km-2 a-1, world mean = 11.9 km -2 -1), but were same order magnitude non-glacial riverine mean, and greater than those documented some major temperate rivers (e.g. Mississippi (1.3 a-1) Nile (0.4 rivers)....
Abstract Glaciers and ice sheets are experiencing rapid warming under current climatic change there is increasing evidence that glacial meltwaters provide key dissolved dissolvable amorphous nutrients to downstream ecosystems. However, large debate exists around the fate of these within complex heterogenous fjord environments, where biogeochemical cycling still often poorly understood. We combine silicon (Si) concentration data with isotopic compositions better understand export in two...
Microbes transported by glacial meltwater streams are thought to be a product of passive dispersal from both supra- and subglacial sources, though studies investigating the origins these assemblages scarce. Here, we conducted survey within large catchment containing multiple glaciers on Qeqertarsuaq (Disko Island), west Greenland, investigate whether meltwater-exported microbial in suspended sediments differ between streams, if they reflect corresponding bulk extraglacial sediment...
Glaciated environments have been highlighted as important sources of bioavailable nutrients, with inputs glacial meltwater potentially influencing productivity in downstream ecosystems. However, it is currently unclear how riverine nutrient concentrations vary across a spectrum cover, making challenging to accurately predict terrestrial fluxes will change continued retreat. Using 40 rivers Chilean Patagonia unique natural laboratory, we investigate cover affects Si and Fe concentrations,...
In high latitude environments, silicon is supplied to river waters by both glacial and non-glacial chemical weathering. The signal of these two end-members often obscured biological uptake and/or groundwater input in the catchment. McMurdo Dry Valleys streams Antarctica have no deep input, connectivity between surface vegetation cover, thus provide a simplified system for us constrain supply dissolved (DSi) rivers from weathering environment. Here we report Si concentrations,...
Glaciers and ice sheets export significant amounts of silicon (Si) to downstream ecosystems, impacting local potentially global biogeochemical cycles. Recent studies have shown Si in Arctic glacial meltwaters an isotopically distinct signature when compared non-glacial rivers. This is likely linked subglacial weathering processes mechanochemical reactions. However, there are currently no isotope (δ30Si) data available from meltwater streams Antarctica, limiting the current inferences on...
The use of silicon (Si) isotopes has led to major advances in our understanding Si cycling modern and past environments. This inter‐laboratory comparison exercise provides the community with first set soil plant reference materials an analytically challenging matrix containing organic material that is known induce isotopic bias, for as secondary isotope measurement. Seven laboratories analysed four (GBW‐07401, GBW‐07404, GBW‐07407, TILL‐1) one (ERM‐CD281). Participating employed a range...
Glacial meltwaters export substantial quantities of dissolved and dissolvable amorphous silicon (DSi ASi), providing an essential nutrient for downstream diatoms.Evidence suggests that glacially exported DSi is isotopically light compared to in non-glaciated rivers.However, the isotopic fractionation mechanisms are not well constrained, indicating important gap our understanding processes global Si cycle.We use rock crushing experiments mimic subglacial physical erosion, provide insight into...
Abstract. The marine silicon cycle is intrinsically linked with carbon cycling in the oceans via biological production of silica by a wide range organisms. stable isotopic composition (denoted δ30Si) siliceous microfossils extracted from sediment cores can be used as an archive past oceanic cycling. However, biogenic has only been measured diatoms, sponges and radiolarians, fractionation relative to seawater entirely unknown for many other silicifiers. Furthermore, biochemical pathways...
Proglacial rivers have been shown to distinctive silicon (Si) isotope compositions, providing new insights into the mechanisms controlling Si cycling in subglacial environment and suggesting terrestrial exports may varied between glacial interglacial periods. However, data are currently limited a small number of systems northern hemisphere, it is unclear how compositions might vary across spectrum influence. Using Chilean Patagonia as unique natural laboratory, we present 0.45 μm filtered...
The basal environments of ice sheets play an important role as places methane (CH4) production, storage, and release. Recent investigations have confirmed the release subglacial microbial origin at western margin Greenland Ice Sheet (GrIS). This may then serve a substrate for methane-consuming microorganisms thus significantly shape community assembly in GrIS environments. We conducted comparative analysis composition exported assemblages from six regions spanning 2,000-km transect along...
Recent studies have shown the release of methane (CH4) from melting Greenland Ice Sheet (GrIS) and identified it as having an additional potential positive climate feedback. This originates mainly acetoclastic methanogenesis in subglacial sediments, accumulates over time, subsequently diffuses into hydrologic network which transports to ice sheet margin. The rates production emission GrIS sediments likely depend on a number factors, including sediment depth distribution, organic matter...
Abstract. The microbial ecosystems that lie beneath ice sheets can impact and contribute to global biogeochemical cycles, yet remain poorly understood given the logistical challenges in directly accessing subglacial environment. Studies instead often rely on indirect sampling of systems via collection meltwaters emerging from margins. However, origin exported material these waters will change over a melt season as glacier hydrology responds changes surface melt. Here, we reveal trends...