Christine Heim

Christine Heim
University of Cologne | UOC · Institute of Geology and Mineralogy

PhD

About

58
Publications
12,259
Reads
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793
Citations
Citations since 2016
31 Research Items
646 Citations
2016201720182019202020212022050100150
2016201720182019202020212022050100150
2016201720182019202020212022050100150
2016201720182019202020212022050100150
Additional affiliations
August 2005 - present
Georg-August-Universität Göttingen

Publications

Publications (58)
Article
Full-text available
The formation of algal and cyanobacterial blooms caused by the eutrophication of water bodies is a growing global concern. To examine the impact of extreme weather events on blooms, eutrophication-related parameters (e.g., water temperature, nitrate, ammonium, nitrite, and soluble reactive phosphate (SRP)) were quantitatively assessed monthly over...
Article
Intensive anthropogenic pressure such as high inputs of nutrients and pesticides severely threaten most European water bodies. Small catchments ≤10 km² are not monitored under the Water Framework Directive but play an important role in freshwater ecosystems. The high complexity in seasonal and spatial dynamics require more than a one-size-fits-all...
Article
Full-text available
Recent discoveries of extant and fossilized communities indicate that eukaryotes, including fungi, inhabit energy-poor and anoxic environments deep within the fractured igneous crust. This subterranean biosphere may constitute the largest fungal habitat on our planet, but knowledge of abyssal fungi and their syntrophic interactions with prokaryotes...
Article
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The oceanic and continental lithosphere constitutes Earth’s largest microbial habitat, yet it is scarcely investigated and not well understood. The physical and chemical properties here are distinctly different from the overlaying soils and the hydrosphere, which greatly impact the microbial communities and associated geobiological and geochemical...
Article
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Lacustrine stromatolites were widespread in the Miocene Wudaoliang Group (stromatolites of the Wudaoliang Group), northern Tibetan Plateau; but only at one location nearby the Wudaoliang Town, they occurred intensively in thick, laterally traceable beds (Wudaoliang stromatolites). Although deposited in lacustrine environment, the lack of fossils in...
Article
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Fractured rocks of impact craters may be suitable hosts for deep microbial communities on Earth and potentially other terrestrial planets, yet direct evidence remains elusive. Here, we present a study of the largest crater of Europe, the Devonian Siljan structure, showing that impact structures can be important unexplored hosts for long-term deep m...
Article
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Organic matter in Archean hydrothermal cherts may provide an important archive for molecular traces of the earliest life on Earth. The geobiological interpretation of this archive, however, requires a sound understanding of organic matter preservation and alteration in hydrothermal systems. Here we report on organic matter (including molecular bios...
Poster
Full-text available
The remoteness of Antarctica offers the perfect environment for the investigation of fundamental biogeochemical processes and developments of terrestrial ecosystems. On James Ross Island, located in the Weddell Sea west of the Antarctic Peninsula, climate conditions are too harsh to provide a home for vascular plants or for terrestrial animals. The...
Article
Full-text available
Organic matter in Archean hydrothermal cherts may provide an important archive for molecular traces of earliest life on Earth. The geobiological interpretation of this archive, however, requires a sound understanding of organic matter preservation and alteration in hydrothermal systems. Here we report on organic matter (including molecular biosigna...
Article
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In the deep biosphere, microbial sulfate reduction (MSR) is exploited for energy. Here, we show that, in fractured continental crystalline bedrock in three areas in Sweden, this process produced sulfide that reacted with iron to form pyrite extremely enriched in 34S relative to 32S. As documented by secondary ion mass spectrometry (SIMS) microanaly...
Article
Available under: https://onlinelibrary.wiley.com/doi/10.1111/gbi.12284 Fossil derivatives of isorenieratene, an accessory pigment in brown‐colored green sulfur bacteria, are often used as tracers for photic zone anoxia through Earth's history, but their diagenetic behavior is still incompletely understood. Here, we assess the preservation of isor...
Article
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An extensive microanalytical isotope study of calcite and pyrite has been carried out in bedrock fractures at Forsmark, Sweden. The very large δ¹³Ccalcite-variation of 103.4‰V-PDB in total (-69.2 to +34.2‰) evidences significant spatial and temporal variability in processes and carbon sources in the deep fracture system during the period when these...
Article
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The deep biosphere is one of the least understood ecosystems on Earth. Although most microbiological studies in this system have focused on prokaryotes and neglected microeukaryotes, recent discoveries have revealed existence of fossil and active fungi in marine sediments and sub-seafloor basalts, with proposed importance for the subsurface energy...
Article
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Stromatolitic iron-rich structures have been reported from many ancient environments and are often described as Frutexites, a cryptic microfossil. Although microbial formation of such structures is likely, a clear relation to a microbial precursor is lacking so far. Here we report recent iron oxidizing biofilms which resemble the ancient Frutexites...
Article
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Microorganisms produce and consume methane in terrestrial surface environments, sea sediments and, as indicated by recent discoveries, in fractured crystalline bedrock. These processes in the crystalline bedrock remain, however, unexplored both in terms of mechanisms and spatiotemporal distribution. Here we have studied these processes via a multi-...
Article
Little research has been conducted on microbial diversity deep under the Earth’s surface. In this study, the microbial communities of three deep terrestrial subsurface aquifers were investigated. Temporal community data over 6 years revealed that the phylogenetic structure and community dynamics were highly dependent on the degree of isolation from...
Article
Little research has been conducted on microbial diversity deep under the Earth's surface. In this study, the microbial communities of three deep terrestrial subsurface aquifers were investigated. Temporal community data over 6 years revealed that the phylogenetic structure and community dynamics were highly dependent on the degree of isolation from...
Article
Full-text available
Precipitation of exceptionally 13C-depleted authigenic carbonate is a result of, and thus a tracer for, sulphate-dependent anaerobic methane oxidation, particularly in marine sediments. Although these carbonates typically are less depleted in 13C than in the source methane, because of incorporation of C also from other sources, they are far more de...
Article
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Conditioning films and biofilms forming on surfaces of solid materials exposed to aqueous media play a key role in in the interaction between the geo- and biospheres. In this study, time-of-flight secondary ion mass spectrometry and scanning electron microscopy were used to investigate the time scale, mode of formation, and chemistry of conditionin...
Article
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Oxidation and reduction of iron can occur through abiotic (chemical) and biotic (microbial) processes. Abiotic iron oxidation is a function of pH and O2 concentration. Biotic iron oxidation is carried out by a diverse group of bacteria, using O2 or NO3 as terminal electron acceptors. At circumneutral pH, both processes occur at similar rates and co...
Article
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Processes of iron mineralization are of great significance to the understanding of Early-Earth geochemistry. Of specific interest are processes at circumneutral pH, where chemical oxidation of Fe can outcompete biological oxidation. To better understand microbially-induced mineral formation and the composition of the involved microbial communities,...
Article
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The 450 m deep Äspö Hard Rock Laboratory (Äspö HRL) provides a unique opportunity to access different aquifer systems within the Precambrian granodioritic basement of the Baltic Shield. In this study, emphasis will be placed on systematic variations of the isotopic and chemical composition including fractionation patterns of rare earth elements (RE...
Article
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Microbial iron oxyhydroxides are common deposits in natural waters, recent sediments and mine drainage systems and often contain significant accumulations of trace and rare earth elements (TREE). TREE patterns are widely used to characterize minerals and rocks, and to elucidate their evolution and origin. Whether and which characteristic TREE signa...
Article
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If O2 is available at circumneutral pH, Fe(2+) is rapidly oxidized to Fe(3+), which precipitates as FeO(OH). Neutrophilic iron oxidizing bacteria have evolved mechanisms to prevent self-encrustation in iron. Hitherto, no mechanism has been proposed for cyanobacteria from Fe(2+)-rich environments; these produce O2 but are seldom found encrusted in i...
Article
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With an aim to increase the understanding about the isotopic and chemical heterogeneity of calcites in water-conducting fracture zones with different crystalline wall rock compositions at different depths, we present trace element chemistry, isotopic composition (δ18O, δ13C, 87Sr/86Sr) and biomarkers of euhedral low-temperature fracture-coating cal...
Article
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The 450 m deep Äspö Hard Rock Laboratory (Äspö HRL), run by the Swedish Nuclear Fuel and Waste Management Co. (SKB) offers a unique opportunity to access microbial systems within Precambrian, mostly granodioritic rocks of the Baltic Shield. Biofilms and microbial mats at a deep groundwater seepage site and an associated pond exhibit a large diversi...
Article
Rationale: Over the last decade, the high lateral resolution and imaging capabilities of time-of-flight secondary ion mass spectrometry (ToF-SIMS) have increasingly stimulated interest in studying organic molecules in complex environmental materials. However, unlike with the established mass spectrometric techniques, the use of ToF-SIMS in the bio...
Article
Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is a surface sensitive MS technique that offers a new way of studying lipid biomarkers at the microscopic level, without the need to destroy the physical integrity of the sample by extraction. We applied ToF-SIMS to a cryosection of a microbial mat and compared the results with ToF-SIMS and...
Article
Fracture minerals within the 1.8-Ga-old Äspö Diorite (Sweden) were investigated for fossil traces of subterranean microbial activity. To track the potential organic and inorganic biosignatures, an approach combining complementary analytical techniques of high lateral resolution was applied to drill core material obtained at -450 m depth in the Äspö...
Chapter
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Foraminifera are the most abundant sessile organisms found on ferromanganese crusts and nodules (Greenslate 1974; Wendt 1974; Dugolinsky et al. 1977; Riemann 1983; von Stackelberg 1984; Mullineaux 1987, 1988; Verlaan 1992; Resig and Glenn 1997; Toscano and Raspini 2005). In fact, actual ferromanganesecrusts and nodules share numerous similarities w...
Chapter
Full-text available
SynonymsColloform limonitic crusts; Frutexites crusts; Frutexites-like forms; Frutexites microstromatolite; Frutexites tuffs; Haematitic/ferruginous/iron microstromatolites; Iron dendritic aggregates; Iron shrubs; Pillar-shaped microstromatolitesDefinitionFrutexites is a problematic microfossil rich in iron. From a taxonomic point of view, only fiv...
Chapter
The Äspö Hard Rock Laboratory (Äspö HRL) is a tunnel located near Oskarshamn in the southeast of Sweden, that serves as a testing environment for the disposal of nuclear waste. The Äspö HRL hosts and makes accessible a wide spectrum of microbially driven subsurface ecosystems (Pedersen 1997).
Article
In recent years, time-of-flight secondary ion mass spectrometry (ToF-SIMS) with cluster ion sources has opened new perspectives for the analysis of lipid biomarkers in geobiology and organic geochemistry. However, published ToF-SIMS reference spectra of relevant compounds are still sparse, and the influence of the chemical environment (matrix) on t...
Article
Full-text available
The microbially mediated anaerobic oxidation of methane (AOM) supposedly follows the overall chemical equation CH4 + SO42- HCO3- + HS- + H2O and is now identified as the major sink of the greenhouse gas in marine systems (Reeburgh 1996; Hinrichs and Boetius 2002 and references therein). In the meantime the AOM is also found in terrestrial fluid ven...
Article
Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is a powerful method for the chemical analysis of solid surfaces. In this paper, the capabilities and limitations of this technique and the potential for its use in geochemical research are outlined. Using ToF-SIMS, the chemical composition of sample structures down to 10-100 mu m can be det...
Article
Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) with a bismuth cluster primary ion source was used for analysing microbial lipid biomarkers in 10-µm-thick microscopic cryosections of methanotrophic microbial mats from the Black Sea. Without further sample preparation, archaeal isopranyl glycerol di- and tetraether core lipids, together wi...

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Projects

Projects (4)
Project
The overarching goal of this project is to identify key players of the endolithic communities that influence and modify surrounding mineral phases including evaporitic substrates of the Atacama Desert. Find more details on the project webside: https://sfb1211.uni-koeln.de/index.php
Project
The biogeochemical investigation of recent biofilms resembling fossil Frutexites and the identification of characteristic biosignatures will help to unravel the key-organisms and processes responsible for the formation of the ancient Frutexites and their relevance for the ancient iron cycle.
Project
Since 12 years Lake Seeburg (Lower Saxony) suffers from severe cyanobacterial blooms. The biogeochemical investigations of the sediments enable to reconstruct the environmental changes of the last decades and to deduce potential remediation solutions.