A5053222293- Geology and Paleoclimatology Research
- Geochemistry and Elemental Analysis
- Paleontology and Stratigraphy of Fossils
- Isotope Analysis in Ecology
- Marine and coastal ecosystems
- Methane Hydrates and Related Phenomena
- Geochemistry and Geologic Mapping
- Marine Biology and Ecology Research
- Groundwater and Isotope Geochemistry
- Mercury impact and mitigation studies
- Geological and Geochemical Analysis
- Radioactive element chemistry and processing
- Calcium Carbonate Crystallization and Inhibition
- Heavy metals in environment
- Microbial Community Ecology and Physiology
- Advanced Battery Materials and Technologies
- Advancements in Battery Materials
- Geological and Geophysical Studies
- Oceanographic and Atmospheric Processes
- Geological formations and processes
- Atmospheric and Environmental Gas Dynamics
- Marine and environmental studies
- Thallium and Germanium Studies
- Metabolism and Genetic Disorders
- Maritime Navigation and Safety
Woods Hole Oceanographic Institution
2015-2025
Max Planck Institute of Colloids and Interfaces
2024-2025
University of Hawaiʻi at Mānoa
2022
University of Southern Mississippi
2018
Woodwell Climate Research Center
2015
University of Oxford
2011-2014
Imperial College London
2010
Research into natural mass‐dependent stable isotope fractionation of cadmium has rapidly expanded in the past few years. Methodologies are diverse with MC‐ICP‐MS favoured by all but one laboratory, which uses thermal ionisation mass spectrometry (TIMS). To quantify and correct for instrumental bias, double‐spike techniques, sample‐calibrator bracketing or element doping been used. However, easy comparison between data sets hampered multitude in‐house Cd solutions used as zero‐delta reference...
Significance The Great Oxidation Event (GOE) ca. 2,400 to 2,050 Ma caused the first significant accumulation of free oxygen in atmosphere and potentially a dramatic growth oxidant reservoirs on Earth’s surface suggested “oxygen overshoot.” However, termination this event remains poorly understood. Here, we present geochemical data suggesting drastic decline gross primary productivity across end-GOE transition, delineating shift from “feast” “famine” conditions characteristic next 1 billion y.
The global marine distributions of Cd and phosphate are closely correlated, which has led to being considered as a micronutrient, despite its toxicity life. explanation for this nutrient-like behavior is unknown because there only one identified biochemical function Cd, an unusual Cd/Zn carbonic anhydrase. Recent developments in isotope mass spectrometry have revealed that uptake by phytoplankton causes isotopic fractionation the open ocean culture. Here we investigate physiochemical...
Ocean export production is a key constituent in the global carbon cycle impacting climate. Past ocean commonly estimated by means of barite and Barium proxies. However, precise mechanisms underlying precipitation undersaturated marine water column are not fully understood. Here we present detailed mineralogical crystallographic analysis from size-fractionated particulate material collected using multiple unit large volume in-situ filtration systems North Atlantic Southern Ocean. Our data...
Geochemical analyses of sedimentary barites (barium sulfates) in the geological record have yielded fundamental insights into chemistry Archean environment and evolutionary origin microbial metabolisms. However, question how were able to precipitate from a contemporary ocean that contained only trace amounts sulfate remains controversial. Here we report dissolved particulate multi-element barium-isotopic data Lake Superior evidence pelagic barite precipitation at micromolar ambient sulfate....
Abstract Phytoplankton productivity and export sequester climatically significant quantities of atmospheric carbon dioxide as particulate organic through a suite processes termed the biological pump. Constraining how pump operated in past is important for understanding concentrations Earth's climate history. However, reconstructing history requires proxies. Due to their intimate association with processes, several bioactive trace metals isotopes are potential proxies phytoplankton...
Abstract Groundwater-derived solute fluxes to the ocean have long been assumed static and subordinate riverine fluxes, if not neglected entirely, in marine isotope budgets. Here we present concentration data for Li, Mg, Ca, Sr, Ba coastal groundwaters constrain importance of groundwater discharge mediating magnitude isotopic composition terrestrially derived ocean. Data were extrapolated globally using three independent volumetric estimates waters, from which estimate that...
The development of versatile strategies for preparing functional carbon materials is essential advancing a wide range applications in science. Precursor design plays pivotal role governing the chemistry and structure target applications. In this work, we report synthesis Meldrum's acid derivatives through Knoevenagel condensation with aromatic heterocycles such as pyrrole, furan, thiophene, which serve precursors carbonaceous tailored chemical electronic properties. thermal these proceeds...
Barium isotopes in mid-ocean ridge basalts reveal that the global upper mantle is contaminated with small amounts of sediment.
Ediacaran sediments record an unusual global carbon cycle perturbation that has been linked to widespread oceanic oxygenation, the Shuram negative C isotope excursion (NCIE). However, proxy-based estimates of ocean redox conditions during this event have limited largely due proxy specificity (e.g., euxinic for Mo and U isotopes). Modern seawater documents a homogenous Tl composition (ε205 = -6.0) significant manganese oxide burial, which is recorded in modern sediments. Here, we provide new...
Abstract. Barium is widely used as a proxy for dissolved silicon and particulate organic carbon fluxes in seawater. However, these applications are limited by insufficient knowledge of the distribution Ba ([Ba]). For example, there significant spatial variability barium–silicon relationship, ocean chemistry may influence sedimentary preservation. To help address issues, we developed 4095 models predicting [Ba] using Gaussian process regression machine learning. These were trained to predict...
Iodine intersects with the marine biogeochemical cycles of several major elements and can influence air quality through reactions tropospheric ozone. is also an element interest in paleoclimatology, whereby iodine-to-calcium ratios carbonates are widely used as a proxy for past ocean redox state. While inorganic iodine seawater found predominantly its reduced oxidized anionic forms, iodide (I − ) iodate (IO 3 ), rates, mechanisms intermediate species by which between these pools poorly...
The geochemistry of Cd in seawater has attracted significant attention owing to the nutrient‐like properties this element. Recent culturing studies have demonstrated that is a biologically important trace metal plays role sequestration inorganic carbon. This conclusion supported by recent isotope data for dissolved and incorporated cultured phytoplankton. These results show plankton features isotopically light while Cd‐depleted surface waters typically exhibit complimentary heavy...
Significance The vertical supply of dissolved Fe (iron) is insufficient compared with the physiological needs marine phytoplankton in vast swathes open ocean. However, relative importance main sources “new” to ocean—continental mineral dust, hydrothermal exhalations, and sediment dissolution—and their temporal evolution are poorly constrained. By analyzing isotopic composition sediments, we find that much central Pacific Ocean originated from sedimentary thousands meters below sea surface....