N. Pedentchouk

N. Pedentchouk
University of East Anglia | UEA · School of Environmental Sciences

PhD in Geosciences

About

90
Publications
11,473
Reads
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Introduction
I focus on the development and application of molecular and stable isotope geochemistry to environmental chemistry and ecosystem sciences, fossil fuel exploration; main interests include: • characterisation of petroleum source rocks • source apportionment of organic pollutants • investigation of C export from terrestrial biosphere • research on C cycling in the Arctic • development of biomarker proxies for ice extent in polar regions • methodology for food quality and geographic provenancing
Additional affiliations
March 2011 - present
University of East Anglia
Position
  • Lecturer
October 2007 - present
University of East Anglia
Position
  • Professor (Associate)
May 2006 - September 2007
The University of Calgary
Position
  • PostDoc Position
Education
September 1998 - May 2004
Pennsylvania State University
Field of study
  • Geosciences

Publications

Publications (90)
Article
The transfer of dissolved organic carbon (DOC) from land to watercourses plays a major role in the carbon cycle, and in the transport and fate of associated organic and inorganic contaminants. We investigated, at global scale, how the concentrations and properties of riverine DOC depend upon combinations of terrestrial source solutions. For topsoil...
Article
Full-text available
This study investigates the magnitude and direction of stable C and H isotope shifts of n-C15–30 alkanes from biodegraded oils sourced from Type II (Oil suite S) and Type II/III (Oil suite H) kerogens. Compound-specific isotope data show a 2.0‰ 13C-enrichment and no D-enrichment of n-alkanes in the most biodegraded oil from sample suite S. Similarl...
Chapter
The analysis of carbon and hydrogen stable isotope ratios of lipids from natural products is an integral component of research in Earth sciences. The isotopic composition of lipids from algae and higher plants can be linked with various environmental parameters, which makes lipid biomarkers a rich source of information about biological, chemical, a...
Article
A novel tri-unsaturated C25 highly branched isoprenoid (HBI) alkene has been identified in a laboratory culture of the diatom Navicula salinicola and its structure determined using a combination of NMR spectroscopy and gas chromatography–mass spectrometry (GC–MS). This represents the first report of a C25 HBI in a marine diatom from the Navicula ge...
Article
Full-text available
Background The Mariana Trench is the deepest known site in the Earth’s oceans, reaching a depth of ~ 11,000 m at the Challenger Deep. Recent studies reveal that hadal waters harbor distinctive microbial planktonic communities. However, the genetic potential of microbial communities within the hadal zone is poorly understood. Results Here, implemen...
Article
Hydrogen isotopes of plant-derived biomarkers can vary by >100‰ at a single location. Isotope fractionation associated with the movement of water in plant leaves cannot account for this variability alone. Biochemical processes therefore must play a fundamental role in controlling hydrogen isotope fractionation during secondary compound biosynthesis...
Chapter
The analysis of carbon and hydrogen stable isotope ratios of lipids from natural products is an integral component of research in Earth sciences. The isotopic composition of lipids from algae and higher plants can be linked with various environmental parameters, which makes lipid biomarkers a rich source of information about biological, chemical an...
Article
Full-text available
Compound-specific isotope analysis (CSIA) of individual organic compounds is a powerful but underutilized tool in petroleum exploration. When integrated with other organic geochemical methodologies it can provide evidence of fluid histories including source, maturity, charge history and reservoir processes that can support field development plannin...
Conference Paper
Full-text available
Sea ice is a key component of the Earth's climate system. It affects the exchange of heat, gases and water between the polar oceans and the atmosphere. Even though changes in sea ice extent and thickness in recent decades are well documented, understanding processes that control climate in the polar regions back in time and over longer time scales...
Article
Fire has been an important component of ecosystems on a range of spatial and temporal scales. Fire can affect vegetation distribution, the carbon cycle, and climate. The relationship between climate and fire is complex, in large part because of a key role of vegetation type. Here, we evaluate regional scale fire–climate relationships during a past...
Article
It has been postulated that a bipolar seesaw interhemispheric mechanism dominated the relationship between the Northern and Southern hemisphere climates since the late Pleistocene. A key test for this proposition would be to undertake palaeoenvironmental studies on terrestrial archives in climatically sensitive regions. Southern Africa's contempora...
Article
It has been postulated that a bipolar seesaw interhemispheric mechanism dominated the relationship between the Northern and Southern hemisphere climates since the late Pleistocene. A key test for this proposition would be to undertake palaeoenvironmental studies on terrestrial archives in climatically sensitive regions. Southern Africa's contempora...
Article
The role of mountain evolution on local climate is poorly understood and potentially underestimated in climate models. One prominent example is East Africa, which underwent major geodynamic changes with the onset of the East African Rift System (EARS) more than 250 Myr ago. This study explores, at the regional East African scale, a molecular approa...
Article
The role of mountain evolution on local climate is poorly understood and potentially underestimated in climate models. One prominent example is East Africa, which underwent major geodynamic changes with the onset of the East African Rift System (EARS) more than 250 Myr ago. This study explores, at the regional East African scale, a molecular approa...
Article
The carbon isotope composition of terrestrial plants records valuable ecophysiological and palaeoecological information. However, interspecies variability in 13C/12C, at both the bulk and compound-specific (CS) level, requires further exploration across a range of ecosystem types. Here, we present bulk and n-alkane δ13C values, and n-alkane concent...
Conference Paper
Full-text available
Sedimentary basins in the South Atlantic contain multiple petroleum systems with source rocks formed in different depositional environments. Published information on organic geochemistry of source rocks in these basins is still very limited. Lacking in particular are molecular level studies that integrate biomarker and stable isotope methodologies....
Conference Paper
Full-text available
The 2 H/ 1 H composition of organic compounds from terrestrial plants has been steadily gaining popularity as a proxy for palaeohydrology. Even though there is a general understanding of the link between the δ 2 H values of precipitation and n-alkyl lipids, there remain several major challenges that need to be addressed when using this proxy in the...
Conference Paper
Full-text available
Palaeohydrological studies typically interpret shifts in sedimentary n-alkyl lipid δ 2 H signals as evidence of changes in the δ 2 H of precipitation and/or aridity. This approach implicitly assumes that any temporal shift in plant species, which vary isotopically and in the amount of n-alkyl lipids they produce, is insignificant compared with the...
Article
Whilst the processes involved in the cycling of dissolved phosphorus (P) in rivers have been extensively studied, less is known about the mechanisms controlling particulate P concentrations during small and large flows. This deficiency is addressed through an analysis of large numbers of suspended particulate matter (SPM) samples collected under ba...
Conference Paper
Full-text available
The use of the 2H/1H composition of terrestrial plants in climate and ecology studies depends on fundamental understanding of the processes within the plant that control fractionation of these two isotopes. Little is currently known about the extent of 2H/1H fractionation at different steps of biosynthesis, after the initial H uptake following leaf...
Conference Paper
Full-text available
Tropics play a key role in the atmospheric circulation, partly responsible for the variations of climatic conditions, as they are a major source of heat and water vapour on Earth. Thus, improving our knowledge on past temperature fluctuations and hydrological regimes in these areas may allow to better constrain the driving forces controlling climat...
Conference Paper
Full-text available
Long chains n-alkanes are components of terrestrial plant leaf waxes that are ubiquitously found in geological archives. They have been extensively used to track environmental and ecological variations in the past, notably changes in vegetation communities. Recent analytical developments led to the possibility of measuring their deuterium to hydrog...
Conference Paper
Full-text available
Priority Sheet on Arctic land-ocean interactions towards the 3rd International Conference on Arctic Research Planning (ICARPIII). Most Arctic coasts are permafrost coasts. There is regional evidence in northern Alaska and the Laptev Sea area for recent acceleration in the rate of coastal erosion. This is related in part to more open water and highe...
Article
The olive (Olea europaea) is one of the most important crops in the Mediterranean region for economic and culinary reasons. Cuticular waxes coat olives and olive leaves and play a significant role in plant physiology and resistance against environmental stresses. The present study describes n-alkane profiles in cuticular waxes of olives and leaves...
Conference Paper
Recent research has identified that interspecies variation in leaf wax n-alkane 2H/1H from plants growing at the same geographical location can exceed 100‰. These differences cannot easily be explained by mechanisms that influence the isotopic composition of leaf water. Biochemical processes are therefore likely to drive some of this variability. C...
Conference Paper
Recent studies of modern terrestrial plants growing at a single location reveal that 2H/1H fractionation between source water and leaf wax n-alkyl lipids can vary by up to 100‰. This provides a challenge for interpreting sedimentary n-alkyl δ2H records, because the contribution of isotopically different plants can shift through time. Palaeohydrolog...
Article
Full-text available
We use first field-based observations of precipitation and river isotopic chemistry from a three-year study (2009-2011) in rainforest and nearby savannah in central Guyana at the northern rim of the Amazon rainforest to establish the quality of modelled or remotely-sensed datasets. Our 3 years of data capture a reduced rainfall regime in 2009 and a...
Article
Turonian strata of the Bohemian Cretaceous Basin, Central Europe, preserve a basin-scale record of shoreline transgressions and regressions, previously interpreted to have been strongly influenced by short-term eustatic cycles. Here, nearshore siliciclastic strata in two separate sub-basins are correlated to a multi-stratigraphic dataset generated...
Conference Paper
Full-text available
Traceability of the geographic origin of olive oils is an important issue from both commercial and health perspectives. This study evaluates the impact of environmental factors on stable C and H isotope compositions of n-alkanes in extra virgin olive oils from Croatia, France, Greece, Italy, Morocco, Portugal, Slovenia, and Spain. The data are used...
Article
Interpretation of sedimentary n-alkyl lipid δ2H data is complicated by a limited understanding of factors controlling interspecies variation in biomarker 2H/1H composition. To distinguish between the effects of interrelated environmental, physical and biochemical controls on the hydrogen isotope composition of n-alkyl lipids, we conducted linked δ2...
Article
This study emphasizes the importance of rainstorm events in mobilizing carbon at the soil-stream interface from tropical rainforests. Half-hourly geochemical/isotopic records over a 13.5 hour period from a 20 km2 tropical rainforest headwater in Guyana show an order of magnitude increase in dissolved organic carbon (DOC) concentration in less than...
Conference Paper
Palaeohydrological studies have increasingly utilised the 2H/1H composition of leaf wax n-alkyl lipids to extract information from the geological record. Interpretation of the sedimentary biomarker δ2H signal, however, requires detailed understanding of the mechanisms controlling hydrogen isotope fractionation between source water and n-alkly lipid...
Article
Full-text available
Glaucousness is described as the scattering effect of visible light from wax deposited on the cuticle of plant aerial organs. In wheat, two dominant genes lead to non-glaucous phenotypes, Inhibitor of wax 1 (Iw1) and Iw2. The molecular mechanisms and the exact extent (beyond visual assessment) by which these genes affect the composition and quantit...
Article
The deuterium/hydrogen (D/H) composition of water and hydrocarbon gases is widely used in geological, environmental and petroleum studies. The aim of this work was to develop a simple reduction zirconium dioxide solid electrolyte reactor (SER) for water decomposition and new methods for measuring hydrogen isotope ratios in water and hydrocarbon gas...
Article
Continental rift deposits contain critical clues concerning the evolution of extensional tectonics, yet such evidence is often obscure due to poor geochronology, burial by younger deposits, or later tectonic overprinting. We revisit Corinth rift development, which began as distributed extension created synrift depocenters with rivers flowing into s...
Conference Paper
Full-text available
Palaeoclimate studies of fossil plant material employing δ13C measurements traditionally focus either on the variation in the 13C content of organic material as a record of the 13C/12C composition of atmospheric CO2, or the distribution of C3 vs. C4 vegetation to infer broad-scale climatic shifts. The development of compound-specific isotope techni...
Article
Stable isotopic compositions of oxygen and hydrogen are used widely to investigate modern and ancient water cycles. The D/H composition of organic compounds derived from terrestrial plants has recently attracted significant attention as a proxy for palaeohydrology. However, the role of various plant physiological and biochemical factors in controll...
Article
Western Siberia is a large region that comprises a substantial portion of northern Asia. In spite of its large size, western Siberia is relatively homogenous in terms of its topography, which is dominated by large plains and low hills, and climate. Consequently, this area is an ideal target for studying past climate, because even a restricted numbe...
Article
During the last decade, compound-specific hydrogen isotope analysis of plant leaf-wax and sedimentary n-alkyl lipids has become a promising tool for paleohydrological reconstructions. However, with the exception of several previous studies, there is a lack of knowledge regarding possible effects of early diagenesis on the δD values of n-alkanes. We...
Article
Hydrogen isotopic composition of plant biomass provides crucial information about plant ecophysiology and local hydrology. Little is known about the apparent fractionation between hydrogen in source water and epicuticular leaf waxes of coniferous tree species that dominate the boreal forest ecosystem exposed to prolonged periods of sunlight during...
Article
The Tunguska Basin in Siberia contains hundreds of phreatomagmatic breccia pipes and a dozen overlying crater lake deposit formed contemporaneously with the Siberian Traps. These structures were created by the violent eruption-inducing interaction of basaltic magma with gigatonnes of greenhouse gases evolved from sill intrusions into organic rich s...
Article
D/H composition of individual organic compounds derived from leaf wax may provide a wealth of information regarding plant-water relations in studies of plant ecology and climate change. Extracting that information from the organic D/H signal requires a thorough understanding of hydrogen isotope fractionation between environmental water and organic...
Conference Paper
There is high demand for new techniques to assist the geographic characterization of quality foodstuffs as part of food security and authentication programs. Bulk stable isotope methods have previously shown great promise in this area. The main aim of our study was to investigate the potential of employing compound-specific analysis of nalkanes in...
Article
Forensic science is an integrative discipline that requires material evidence from diverse sources. Geochemical evidence derived from inorganic and organic substances is becoming increasingly popular among law enforcement agencies in industrialized countries. Previous investigations indicate that the relative distributions of individual plant-deriv...
Article
The Lower Palaeozoic (Upper Ordovician–Silurian) succession of North Africa contains one of the world's most prolific black shale source rocks, yet the origin of these rocks remains contentious. The black shale of the Batra Formation in Jordan was deposited at high palaeolatitude during rapid Hirnantian to early Silurian deglaciation. Here we repor...
Article
This study investigates stable carbon and hydrogen isotope compositions of leaf wax n-alkanes from 3 angiosperm and 2 conifer species from a semi-desert natural environment. The δ13C and δD n-C27 alkane data show a clear distinction between Populus tremuloides/Syringa vulgaris (−31.9 to −32.7‰ and −168 to −186‰, respectively) and Pinus sylvestris/P...
Article
Full-text available
Compound-specific nitrogen, carbon, and hydrogen isotope records from sediments of Sky Pond, an alpine lake in Rocky Mountain National Park (Colorado, United States of America), were used to evaluate factors contributing to changes in diatom assemblages and bulk organic nitrogen isotope records identified in lake sediments across Colorado, Wyoming,...
Article
Full-text available
The Palaeocene/Eocene thermal maximum represents a period of rapid, extreme global warming ,55 million years ago, superimposed on an already warmworld1–3. This warming is associated with a severe shoaling of the ocean calcite compensation depth4 and a >2.5 per mil negative carbon isotope excursion in marine and soil carbonates1–4. Together these ob...
Article
Full-text available
The Palaeocene/Eocene thermal maximum represents a period of rapid, extreme global warming approx55 million years ago, superimposed on an already warm world. This warming is associated with a severe shoaling of the ocean calcite compensation depth and a >2.5 per mil negative carbon isotope excursion in marine and soil carbonates. Together these obs...
Article
Full-text available
The Palaeocene/Eocene thermal maximum, approximately 55 million years ago, was a brief period of widespread, extreme climatic warming, that was associated with massive atmospheric greenhouse gas input. Although aspects of the resulting environmental changes are well documented at low latitudes, no data were available to quantify simultaneous change...
Article
The Palaeocene/Eocene thermal maximum, ~55 million years ago, was a brief period of widespread, extreme climatic warming, that was associated with massive atmospheric greenhouse gas input. Although aspects of the resulting environmental changes are well documented at low latitudes, no data were available to quantify simultaneous changes in the Arct...
Article
This study investigates the extent of post-depositional alteration of δD values of n-alkyl lipids, isoprenoids, and kerogen isolated from a continuous 450m core that covers the transition from thermally immature to early mature sediments in the lacustrine Kissenda Formation, Lower Cretaceous, Gabon Basin. Large variations in δD values (up to 40‰ fo...