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November 2008 - present
January 2010 - present
Publications
Publications (367)
Benzocarbazole (BC) migration tracers were used to investigate the complex filling of reservoir segments at the Solveig field in the Norwegian North Sea. The study suggests that the benzocarbazole ratio [a]/([a]+[c]) of crude oils and extracts decreases with inferred increasing migration distance. The complex filling history of the Solveig field is...
The Pliensbachian-Toarcian (Pl-To) boundary was marked by an extinction event in marine organisms, and localised ocean anoxia – resulting in the deposition of black shales. Negative isotopic excursions in bulk organic carbon in many of these black shales, are widely believed to indicate that a global carbon cycle disruption accompanied this extinct...
The warm Miocene (23.0–5.3 Ma) is considered a model case for the global climate of the near future. In view of the current coral reef crisis, studies on Miocene reefs can contribute to predictions regarding the stress resilience of today's reefs against global warming. A Late Miocene (6.2–5.5 Ma) reef coral fauna from Hispaniola Island (Caribbean)...
The Pliensbachian/Toarcian boundary interval represents a transition from a coldhouse into a hothouse climate state, involving the demise of a land-based cryosphere, initiating a third-order global sea-level rise. Within the intensely studied Northwest Tethyan shelf region, the South-German Basin has been investigated in more detail than the North-...
The Late Miocene Cooling (LMC) has been recognized as a global event in the climate record and posited as the start of modern ecosystems. Whereas shifts in modern terrestrial ecosystems around 7.0 – 5.5 Ma occur globally, little is known about changes in aquatic ecosystems. This is especially true of shallow water carbonate ecosystems, such as cora...
Environmental perturbations of the Toarcian Anoxic Event and its associated carbon isotope excursion (CIE) occurred in a cyclic fashion indicating an orbital control mechanism. Sedimentary strata of the E. elegantulum ammonite subzone in the Lorraine Sub-basin, Luxembourg, exhibit eight sedimentary cycles, most of which postdate the CIE, implying t...
The Toarcian Oceanic Anoxic Event (T-OAE, Early Jurassic) is marked by widespread marine deoxygenation and deposition of organic carbon (OC)-rich strata. The genesis of the T-OAE is thought to be associated with environmental changes caused by the emission of ¹² C-enriched greenhouse gasses (CO 2 , CH 4 ), manifested in a negative Toarcian carbon i...
Fossilised true ferns (Pecopteris sp.) preserved in siderite concretions from the Mazon Creek Lagerstätte (Illinois) presented a unique opportunity to characterise the organic signatures of these late Carboniferous plants. Localised analyses of true fern fossils showed several highly abundant phytohopanoids and fernane/arborane derived aromatic pro...
The flooding of the Pliensbachian shelf of the North-South Axis of Central Tunisia during the early Toarcian favoured the development of organic-rich facies in the most subsiding areas, such as that represented by the Châabet El Attaris section. The lower Toarcian strata in this section is represented by organic matter-rich sedi-
ments (dark lamina...
Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are common in lake sediments, where they are frequently employed to infer mean annual air temperatures (MAAT) or air temperatures of months above freezing (MAF) using the MBT'5Me lipid paleothermometer. The reliable reconstruction of such temperatures, however, requires robust calibration fun...
Variability in organic matter types and quality of source rock intervals across evolving rift-basins has been the focus of previous studies, which have shown that due to dynamic sedimentary regimes and water depths such source intervals occur sporadically and restricted to specific stratigraphic horizons. Such heterogeneous settings, require detail...
The Great Barrier Reef (GBR) is by far the largest reef system in the modern ocean. Recently, it has been severely affected by coral bleaching due to human-induced warming. To date, however, the influence of temperature on the origin and long-term evolution of the GBR remains enigmatic. The only available sea surface temperature (SST) proxy data se...
This study reports on plastiglomerate and other new forms of plastic pollution in the tropical marine continent of Indonesia. Twenty-five samples were collected from an island beach in the Java Sea where plastiglomerate, plasticrusts, and pyroplastic were formed by the uncontrolled burning of plastic waste. The most common plastic types were polyet...
The climate and paleoenvironmental evolution of the East Asian continent and adjacent Northwest Pacific Ocean is governed by the interplay of the region's dominant features in oceanic and atmospheric circulation, which control the redistribution of heat and moisture. In the atmospheric realm, the subtropical westerly jet stream and East Asian monso...
The possibility of a collapse (or marked weakening) of the Atlantic Meridional Overturning Circulation (AMOC) within a few centuries boosted the interest of the scientific community on the responses of different compartments of the climate system to past AMOC collapses (or marked weakening). The most recent examples of such periods are Heinrich Sta...
Variability in organic matter types and quality of source rock intervals across evolving rift-basins has been the focus of previous studies, which have shown that due to dynamic sedimentary regimes and water depths such source intervals occur sporadically and restricted to specific stratigraphic horizons. Such heterogeneous settings, require detail...
Evidence shows that in the modern ocean, coral reefs are disappearing, and these losses are tied to climate change. However, research also shows that coral reefs can adapt rapidly to changing conditions leading some researchers to suggest that some reef systems will survive future climate change through adaptation. It is known that there were chang...
In the past decades, lower Toarcian strata have gained attention on a global paleogeographical scale but these strata have been poorly studied along the East African margin. This study presents a comprehensive review of the Toarcian geological evolution of the East African Coastal Margin focusing mainly on the Mandawa Basin in Tanzania, the Moronda...
The contribution of agriculture to the Sustainable Development Goals requires climate‐smart and profitable farm innovations. Increasing the ammonia fertilizer applications to meet the global food demands results in high agricultural costs, environmental quality deterioration, and global warming, without a significant increase in crop yield. Here, w...
Over many decades, an understanding of total organic carbon (TOC) variability in various sedimentary basins has been constrained by the availability of suitable samples for geochemical analysis. Many attempts rely on selected sidewall core or cuttings samples, which do not provide a continuous lithological record of the succession. As a result, TOC...
Orbital-driven climate fluctuations and associated variations in the carbon cycle over short- and long-term time scales can be recorded in sedimentary archives. Bulk geochemical, biomarker, and stable isotope signatures in sediments deposited at the end of the Early Eocene Climatic Optimum (EECO) recovered from the Chicxulub impact crater in the Gu...
N2‐fixing heterocytous cyanobacteria are considered to play a minor role in sustaining coastal microbial mat communities developing under normal marine to hypersaline conditions. Here, we investigated microbial mats growing under different salinities from freshwater mats of Giblin River (Tasmania) to metahaline and hypersaline mats of Shark Bay (We...
Severe environmental changes during the early Toarcian (Early Jurassic; ~182 Ma), comprising global warming, elevated pCO2, intensified continental weathering and a high amplitude sea level rise, led to the genesis of a Toarcian Oceanic Anoxic Event (T-OAE), expressed by the widespread occurrence of organic carbon (OC)-rich sediments (black shales)...
The reconstruction of ancient trophic networks is pivotal to our understanding of ecosystem function and change through time. However, inferring dietary relationships in enigmatic ecosystems dominated by organisms without modern analogues, such as the Carboniferous Mazon Creek fauna, has previously been considered challenging: preserved coprolites...
Spectral gamma ray log (SGRL) data has been widely employed to derive subsurface lithological information and to perform well correlation when the core is not available. Previous studies mainly targeted homogenous facies whereas few attempts addressed heterolithic successions. The SGRL investigation here aimed at deriving lithofacies and further co...
The Early Eocene represents the warmest climate during the Cenozoic Era punctuated by transient warming events. Here, we apply for the first time biomarker and stable isotope data to describe the depositional and environmental changes at the actual Chicxulub impact crater [International Ocean Discovery Program (IODP) Site M0077A] during the Early E...
We describe the synthesis of seven C2‐alkylcarbazoles via a sequence of Buchwald–Hartwig coupling of arylamines with aryl halides followed by oxidative cyclization of the resulting diarylamines. Methyl groups at the positions 4 and 5 were introduced by taking advantage of the ortho‐directed palladation of meta‐pivaloyloxy‐substituted diarylamines a...
During the early Toarcian (Early Jurassic, ~183 Ma) global climate and environmental change profoundly impacted biogeochemical cycles and marine ecosystems culminating in the early Toarcian Oceanic Anoxic Event (T-OAE). The T-OAE exhibited a global temperature rise and carbon cycle perturbation that manifested in a stepwise negative Toarcian carbon...
In the Anthropocene, nitrogen pollution is becoming an increasing challenge for both mankind and the Earth system. Microbial nitrogen cycling begins with aerobic nitrification, which is also the key rate−limiting step. For over a century, it has been accepted that nitrification occurs sequentially involving ammonia oxidation, which produces nitrite...
Profound environmental changes punctuated the Early Jurassic period, as recorded by marked carbon and oxygen isotope anomalies and major biotic crises. The response of low-latitude regions of Northern Gondwana to such intense changes is not documented as well as that of other Tethys areas. We present new calcareous nannofossil assemblages from thre...
Over many decades, an understanding of total organic carbon (TOC) variability in various sedimentary basins has been constrained by the availability of suitable samples for geochemical analysis. Many attempts rely on selected sidewall core or cuttings samples, which do not provide a continuous lithological record of the succession. As a result, TOC...
During the early Toarcian (Early Jurassic; ~183 Ma) global environmental changes promoted the expansion of oxygen-deficient conditions across vast shelf areas around the globe. Ocean margin deoxygenation favored the preservation of organic matter in shelf sediments and is considered to reflect a Toarcian Oceanic Anoxic Event (T-OAE). Higher-level g...
Anecic Earthworm casting is the process explaining Chernozem genesis, properties and distribution across Europe. This has consequences for long-term carbon sequestering, sustainable management and protection of these valuable resource. Whereas climatic steppe Chernozems might form since epigeic and endogeic Earthworm species are limited by natural...
Figure 2 of the original article contained an error in the location of some of the radiocarbon dates in Cores 1 and 2. This does not change the main findings of the paper. The corrected figure is below.
The flooding of the Lower Jurassic shelf in the North Gondwana Palaeomargin during the early Toarcian occurred on a fragmented and irregular topography affected by differential subsidence—due to the activity of listric faults along the North-South Axis of Tunisia—that favoured lateral changes in facies and thickness at a kilometric scale. The onset...
Hopanoid molecules are ubiquitous in sedimentary rocks and make up a significant proportion of sedimentary organic matter, oils, and bitumen. Due to their relatively stable chemical structure, they are generally well preserved in the rock record, making them extremely useful as biomarkers or geomarkers. Despite extensive industry and scientific int...
The historical view of an equable Jurassic greenhouse world has been challenged by recent studies documenting recurrent alternation between contrasting climate modes. Cooling of high-latitudinal areas may have been caused by orogenic processes at the northern margin of the Tethys Ocean that reduced the heat-transport towards polar regions. Warm pha...
Wildfires are important in modern ecology but the complex interplay between wildfires and vegetation or climate is less well understood in ancient environments, in particular those of the Arctic regions. This includes the impacts of paleo-wildfires on surrounding marine basins by affecting sedimentation rates and nutrient input via soil degeneratio...
Understanding Earth’s response to climate forcing in the geological past is essential to reliably predict future climate change. The reconstruction of continental climates, however, is hampered by the scarcity of universally applicable temperature proxies. Here, we show that heterocyte glycolipids (HGs) of diazotrophic heterocytous cyanobacteria oc...
The discovery of complete ammonia oxidation (comammox) has altered our understanding of nitrification, which is the rate-limiting process in the global nitrogen cycle. However, understanding the ecological role of comammox or its contribution to nitrification in both natural and artificial ecosystems is still in its infancy. Here, we investigated t...
Investigation of expulsion and primary migration usually suffers from inadequate methodologies failing to simulate natural conditions prevailing during oil and gas formation. The Expulsinator device provides a unique methodology to study these processes under near-natural conditions of pressure as well as near-natural constellation of source rock a...
Provenance studies of Upper Cretaceous Strata
Estimating the environmental and societal impact of recent volcanic eruptions is a task aided by direct measurements and historical sources. Beyond the reach of first-hand accounts, our understanding of pre-historic volcanism is often hindered by dating uncertainties inherent to geological archives. Here, we minimize dating errors by analyzing the...
Thermal stress on the biosphere during the extreme warmth of the Paleocene–Eocene Thermal Maximum (PETM) was most severe at low latitudes, with sea surface temperatures at some localities exceeding the 35 ∘C at which marine organisms experience heat stress. Relatively few equivalent terrestrial sections have been identified, and the response of lan...
In this paper, we use molecular paleothermometry, based on the TEX86 proxy derived from fossilized archaeal lipids, to reconstruct absolute sea surface temperatures (SSTs) for the northwest Tethys Shelf during the late Pliensbachian to early Toarcian (Early Jurassic, ~183 Ma) stages. Our composite record from outcrops in Spain and Italy reveals tha...
Organic geochemistry and palynology reveal major organofacies changes in the marginal marine Polish Basin during the early Toarcian linked to changes in environmental conditions. Increasing water salinity and enhanced biomass contributions from phytoplankton, adopted to brackish conditions, attest to periodic marine ingressions into the paralic, hy...
The Younger Quaternary erosion history was reconstructed in a catchment close to the Chalcolithic giant settlement Maidanetske, central Ukraine based on dated sediment sequences. Four trenches and a long percussion drill-core were analyzed in a valley grading from a Loess covered plateau towards the Talianky River. The sediments were dated by a com...
Abstract. Thermal stress on the biosphere during the extreme warmth of the Paleocene-Eocene Thermal Maximum (PETM) was most severe at low latitudes, with sea surface temperatures at some localities exceeding the 35 °C at which marine organisms experience heat stress. Relatively few equivalent terrestrial sections have been identified, and the respo...
Investigation of aromatic biomarkers extracted from carbonate concretions can contribute to characterize the enhanced microbial activity that mediates carbonate concretion formation. This microbial footprint can be further inferred from the stable isotopic values of carbonate (δ13C) and pyrite (δ34S). Here, we used a combination of GC-MS and GC×GC-...
The Neolithic period in NW-Europe marks a time of major transformation in human lifestyle including sedentism, farming, agropastoralism with early animal husbandry and the use of ornamented pottery by “Funnelbeaker” societies. Domestic animals, in particular cattle, served for traction, plowing, and manuring to support agricultural production but a...
The Younger Dryas (12,680–11,590 yr BP) was the last millennial scale cold event of the Quaternary, when a mean annual temperature decline of 3–5 °C impacted severely on the environment. Whereas pollen distributions document changes in land vegetation, details of limnic ecosystem responses to the cooling event and to its recovery are still not well...
The Expulsinator provides a new technique to simulate generation and expulsion of hydrocarbons under near-natural conditions. This is realized by application of lithostatic pressure onto an intact source rock disc with undisturbed mineral matrix and kerogen network and by hydrous pyrolysis, conducted in open flow-through mode. Conventional pyrolysi...
Plants are excellent climate indicators and their macro-remains or pollen accumulating in geological archives serve as recorders of environmental change. In Europe birch trees contribute importantly to Holocene plant successions. They constitute the dwarf species Betula nana and B. humilis, representing colder and two tree birches, B. pubescens and...
The heterocyte (heterocyst) glycolipid (HG) content of heterocytous (heterocystous) cyanobacteria can principally be separated into two different types. In the first type, the aglycone moiety attached to the sugar headgroup exclusively contains hydroxyl functionalities resulting in the formation of HG diols and HG triols. In the second type, one of...
During the early Toarcian multiple environmental perturbations led to the genesis of the Toarcian Oceanic Anoxic Event (T-OAE), expressed by the widespread occurrence of black shales that were formed under oxygen-deficient conditions. Factors promoting organic matter preservation also drove benthic extinction due to low aqueous O2 levels and habita...
The Chicxulub crater was formed by an asteroid impact at ca. 66 Ma. The impact is considered to have contributed to the end-Cretaceous mass extinction and reduced productivity in the world’s oceans due to a transient cessation of photosynthesis. Here, biomarker profiles extracted from crater core material reveal exceptional insights into the post-i...
Throughout Earth’s history, variations in atmospheric CO2 concentration modulated climate. Understanding changes in atmospheric carbon cycle is therefore pivotal in predicting consequences of recent global warming. Here, we report stable carbon isotopes (δ¹³C) of molecular land plant fossils complemented by bulk organic and inorganic carbon fractio...
The younger Quaternary erosion history was reconstructed in a catchment close to the Chalcolithic giant settlement Maidanetske, central Ukraine based on dated sediment sequences. Four trenches and a long percussion drill-core were analyzed in a valley grading from a Loess covered plateau towards the Talianky River. The sediments were dated via a co...
The younger Quaternary erosion history was reconstructed in a catchment close to the Chalcolithic giant settlement Maidanetske, central Ukraine based on dated sediment sequences. Four trenches and a long percussion drill-core were analyzed in a valley grading from a Loess covered plateau towards the Talianky River. The sediments were dated via a co...
Estimating the environmental and societal impact of recent volcanic eruptions is a task aided by direct measurements and historical sources. Beyond the reach of first-hand accounts, our understanding of pre-historic volcanism is often hindered by the dating uncertainties inherent to stratigraphic archives. Here, we minimise this source of error by...
Global-scale N-oxide contamination of groundwater within aquifers occurs due to the widespread use of N-bearing fertilizers and chemicals, threatening both human and environmental health. However, the conversion of these pollutants in active nitrogen (N) cycling processes in the subsurface biosphere still remains unclear. This study investigates th...