A5050164240- Geology and Paleoclimatology Research
- Isotope Analysis in Ecology
- Marine and coastal ecosystems
- Methane Hydrates and Related Phenomena
- Hydrocarbon exploration and reservoir analysis
- Archaeology and ancient environmental studies
- Atmospheric and Environmental Gas Dynamics
- Geological formations and processes
- Climate change and permafrost
- Mass Spectrometry Techniques and Applications
- Groundwater and Isotope Geochemistry
- Toxic Organic Pollutants Impact
- Soil Carbon and Nitrogen Dynamics
- Radioactive contamination and transfer
- Microbial Community Ecology and Physiology
- Analytical Chemistry and Chromatography
- Marine and environmental studies
- Pleistocene-Era Hominins and Archaeology
- Analytical chemistry methods development
- Karst Systems and Hydrogeology
- Metabolomics and Mass Spectrometry Studies
- Petroleum Processing and Analysis
- Microbial bioremediation and biosurfactants
- Space Exploration and Technology
- Soil erosion and sediment transport
Scottish Universities Environmental Research Centre
2016-2025
Board of the Swiss Federal Institutes of Technology
2018-2022
ETH Zurich
2013-2021
Lincoln University
2020
University of Arizona
2017-2019
Institut de l'Information Scientifique et Technique
2017-2019
University of Glasgow
2016-2018
New York University Press
2017
Weizmann Institute of Science
2017
Ion Beam Applications (France)
2016
The Deepwater Horizon blowout is the largest offshore oil spill in history. We present results from a subsurface hydrocarbon survey using an autonomous underwater vehicle and ship-cabled sampler. Our findings indicate presence of continuous plume oil, more than 35 kilometers length, at approximately 1100 meters depth that persisted for months without substantial biodegradation. Samples collected within reveal monoaromatic petroleum concentrations excess 50 micrograms per liter. These data...
Quantitative information regarding the endmember composition of gas and oil that flowed from Macondo well during Deepwater Horizon spill is essential for determining flow rate, total volume released, trajectories fates hydrocarbon components in marine environment. Using isobaric gas-tight samplers, we collected discrete samples directly above on June 21, 2010, analyzed oil. We found fluids flowing had a gas-to-oil ratio 1,600 standard cubic feet per petroleum barrel. Based measured Federally...
Abstract Climate change induced permafrost thaw in the Arctic is mobilizing ancient dissolved organic carbon (DOC) into headwater streams; however, DOC exported from mouth of major arctic rivers appears predominantly modern. Here we highlight that (>20,000 years B.P.) rapidly utilized by microbes (~50% loss <7 days) and decay rates (0.12 to 0.19 day −1 ) exceed those for a river (Kolyma: 0.09 ). Permafrost exhibited unique molecular signatures, including high levels aliphatics were...
Northern high-latitude rivers are major conduits of carbon from land to coastal seas and the Arctic Ocean. warming is promoting terrestrial permafrost thaw shifting hydrologic flowpaths, leading fluvial mobilization ancient stores. Here we describe (14)C (13)C characteristics dissolved organic networks across Kolyma River Basin (Siberia), isotopic changes during bioincubation experiments. Microbial communities utilized (11,300 >50,000 years) in waters millennial-aged (up 10,000 headwater...
Terrestrial vegetation and soils hold three times more carbon than the atmosphere. Much debate concerns how anthropogenic activity will perturb these surface reservoirs, potentially exacerbating ongoing changes to climate system. Uncertainties specifically persist in extrapolating point-source observations ecosystem-scale budgets fluxes, which require consideration of vertical lateral processes on multiple temporal spatial scales. To explore controls organic (OC) turnover at river basin...
Abstract The occurrence of pre-aged organic carbon (OC) in continental margin surface sediments is a commonly observed phenomenon, yet the nature, sources, and causes this aged OC remain largely undetermined for many shelf settings. Here we present results an extensive survey abundance radiocarbon content from northern Chinese marginal seas. Pre-aged associated with both coarser (&gt;63 µm) finer (&lt;63 sedimentary components; measurements on specific grain-size fractions reveal...
Abstract Sediments in deep ocean trenches may contain crucial information on past earthquake history and constitute important sites of carbon burial. Here we present 14 C data bulk organic (OC) its thermal decomposition fractions produced by ramped pyrolysis/oxidation for a core retrieved from the >7.5 km-deep Japan Trench. High-resolution measurements, coupled with distinctive thermogram characteristics OC, reveal hemipelagic sedimentation interrupted episodic deposition pre-aged OC...
Abstract Understanding the effects of hydrodynamic forcing on organic matter (OM) composition is important for assessment carbon (OC) burial in marginal seas regional and global scales. Here we examine relationships between oceanographic conditions (bottom shear stress), physical characteristics (mineral surface area grain size) geochemical properties (OC content [OC%] isotope compositions [ 13 C, 14 C]) a large suite sediments from Chinese to assess influence processes fate OM shallow...
Abstract The mobilization of glacial permafrost carbon during the last glacial–interglacial transition has been suggested by indirect evidence to be an additional and significant source greenhouse gases atmosphere, especially at times rapid sea-level rise. Here we present first direct for release ancient from degrading in East Asia 17 kyrs, using biomarkers radiocarbon dating terrigenous material found two sediment cores Okhotsk Sea. Upscaling our results whole Arctic shelf area, show cycle...
13C NMR analyses of hydrophobic dissolved organic matter (DOM) fractions isolated from a landfill leachate contaminated groundwater near Norman, OK; the Colorado River aqueduct Los Angeles, CA; Anaheim Lake, an infiltration basin for Santa Ana in Orange County, and Tomago Sand Beds, Sydney, Australia, found branched methyl groups quaternary aliphatic carbon structures that are indicative terpenoid hydrocarbon precursors. Significant amounts lignin precursors, commonly postulated to be major...
Abstract Studies using carbon isotopes to understand the global cycle are critical identify and quantify sources, sinks, processes how humans may impact them. 13 C 14 routinely measured individually; however, there is a need develop instrumentation that can perform concurrent online analyses generate rich data sets conveniently efficiently. To satisfy these requirements, we coupled an elemental analyzer stable isotope mass spectrometer accelerator system fitted with gas ion source. We first...
Abstract Vast stores of arctic permafrost carbon that have remained frozen for millennia are thawing, releasing ancient dissolved organic (DOC) to inland waters. Once in waters, DOC can be converted CO 2 and emitted the atmosphere, accelerating climate change. Sunlight‐driven photoreactions oxidize DOC, converting a portion leaving behind photomodified pool matter (DOM). Samples from Kolyma River, its tributaries, streams draining thawing yedoma were collected. Irradiation experiments...
Abstract The stability and potential vulnerability of soil organic matter (SOM) to global change remain incompletely understood due the complex processes involved in its formation turnover. Here we combine compound‐specific radiocarbon analysis with fraction‐specific bulk‐level measurements order further elucidate controls on SOM dynamics a temperate subalpine forested ecosystem. Radiocarbon contents individual compounds isolated from same interval generally exhibit greater variation than...
The deposition and long-term burial of sedimentary organic matter (OM) on continental margins comprises a fundamental component the global carbon cycle. A key unknown in interpretation isotope records OM is extent to which accumulating shelf slope sediments influenced by dispersal redistribution processes. Here, we present results from an extensive survey (OC) characteristics grain size fractions (ranging <20 250 μm) retrieved Chinese marginal sea surface order assess abundance composition...
Abstract. Soil erosion plays a crucial role in transferring sediment and carbon from land to sea, yet little is known about the rhythm rates of soil prior most recent few centuries. Here we reconstruct Holocene erosional history central India, as integrated by Godavari River core Bay Bengal. We quantify terrigenous fluxes, fingerprint sources for lithogenic fraction assess age exported carbon. Taken together, our data show that monsoon decline late significantly increased organic This...
ABSTRACT Compound-specific radiocarbon analysis (CSRA) of benzene polycarboxylic acids (BPCAs) yields molecular-level, source-specific information necessary to constrain isotopic signatures pyrogenic carbon. However, the purification individual BPCAs requires a multistep procedure that typically results in only microgram quantities target analyte(s). Such small samples are highly susceptible contamination by extraneous carbon, which needs be minimized and carefully accounted for order yield...
Abstract. Quantitative constraints on soil organic matter (SOM) dynamics are essential for comprehensive understanding of the terrestrial carbon cycle. Deep is particular interest as it represents large stocks and its turnover times remain highly uncertain. In this study, SOM in both top deep across a climatic (average temperature ∼ 1–9 ∘C) gradient determined using time-series (∼20 years) 14C data from bulk water-extractable (WEOC). Analytical measurements reveal enrichment bomb-derived...
<title>Abstract</title> The Gulf Stream forms part of the upper-ocean limb Atlantic Meridional Overturning Circulation (AMOC), playing an essential role in redistributing heat northward and greatly influencing regional climates North Atlantic. Understanding path strength variability on longer timescales is vital to contextualise its present-day weakening fully appreciate sensitivity forcing. We present a 558-year long (1456–2013) proxy record sea surface temperature from Bermudan stalagmite...
A new and unique radiocarbon accelerator mass spectrometry (AMS) facility has been constructed at the Woods Hole Oceanographic Institution. The defining characteristic of system is its large-gap optical elements that provide a larger-than-standard beam acceptance. Such ideally suited for high-throughput, high-precision measurements 14 C. Details performance are presented.
Ocean dynamics served an important role during past dramatic climate changes via impacts on deep-ocean carbon storage. Such are recorded in sedimentary proxies of hydrographic change continental margins, which lie at the ocean-atmosphere-earth interface. However, interpretations these records challenging, given complex interplays among processes delivering particulate material to and from ocean margins. Here we report radiocarbon (