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Evaluating the multiple sulfur isotope signature of Eoarchean rocks from the Isua Supracrustal Belt (Southwest‐Greenland) by MC‐ICP‐MS: Volcanic nutrient sources for early life Geobiology (IF 3.7) Pub Date : 2024-04-10 Jane E. Macdonald, Patrick Sugden, Matthew Dumont, Kristoffer Szilas, Stijn Glorie, Alexander Simpson, Sarah Gilbert, Andrea Burke, Eva E. Stüeken
On the anoxic Archean Earth, prior to the onset of oxidative weathering, electron acceptors were relatively scarce, perhaps limiting microbial productivity. An important metabolite may have been sulfate produced during the photolysis of volcanogenic SO2 gas. Multiple sulfur isotope data can be used to track this sulfur source, and indeed this record indicates SO2 photolysis dating back to at least
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Calcium isotope fractionation by intracellular amorphous calcium carbonate (ACC) forming cyanobacteria Geobiology (IF 3.7) Pub Date : 2024-04-09 Neha Mehta, Harold Bradbury, Karim Benzerara
The formation of intracellular amorphous calcium carbonate (ACC) by various cyanobacteria is a widespread biomineralization process, yet its mechanism and importance in past and modern environments remain to be fully comprehended. This study explores whether calcium (Ca) isotope fractionation, linked to ACC‐forming cyanobacteria, can serve as a reliable tracer for detecting these microorganisms in
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Preserved particulate organic carbon is likely derived from the subsurface sulfidic photic zone of the Proterozoic Ocean: evidence from a modern, oxygen‐deficient lake Geobiology (IF 3.7) Pub Date : 2024-03-13 Ashley B. Cohen, Lisa N. Christensen, Felix Weber, Milana Yagudaeva, Evan Lo, Gregory A. Henkes, Michael L. McCormick, Gordon T. Taylor
Biological processes in the Proterozoic Ocean are often inferred from modern oxygen‐deficient environments (MODEs) or from stable isotopes in preserved sediment. To date, few MODE studies have simultaneously quantified carbon fixation genes and attendant stable isotopic signatures. Consequently, how carbon isotope patterns reflect these pathways has not been thoroughly vetted. Addressing this, we profiled
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Nubecularia‐coralline algal‐serpulid‐microbial bioherms of the Paratethys Sea—Distribution and paleoecological significance (upper Serravallian, upper Sarmatian, Middle Miocene) Geobiology (IF 3.7) Pub Date : 2024-03-12 Werner E. Piller, Mathias Harzhauser
Nubecularia bioherms represent unique bioconstructions that are restricted to the upper Serravallian of the Paratethys and have been reported since the 19th century. They occur in the Central Paratethys in the late Sarmatian and the Eastern Paratethys in the Bessarabian both regional stages of the respective Paratethyan areas. In this study, several locations in the Vienna and Styrian basins of the
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Comprehensive molecular‐isotopic characterization of archaeal lipids in the Black Sea water column and underlying sediments Geobiology (IF 3.7) Pub Date : 2024-03-11 Qing‐Zeng Zhu, Marcus Elvert, Travis B. Meador, Jan M. Schröder, Katiana D. Doeana, Kevin W. Becker, Felix J. Elling, Julius S. Lipp, Verena B. Heuer, Matthias Zabel, Kai‐Uwe Hinrichs
The Black Sea is a permanently anoxic, marine basin serving as model system for the deposition of organic‐rich sediments in a highly stratified ocean. In such systems, archaeal lipids are widely used as paleoceanographic and biogeochemical proxies; however, the diverse planktonic and benthic sources as well as their potentially distinct diagenetic fate may complicate their application. To track the
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Groundwater microbial communities reflect geothermal activity on volcanic island Geobiology (IF 3.7) Pub Date : 2024-03-09 Sheree J. Watson, Cédric Arisdakessian, Maria Petelo, Kekuʻiapōiula Keliipuleole, Diamond K. Tachera, Brytne K. Okuhata, Kiana L. Frank
Studies of the effects of volcanic activity on the Hawaiian Islands are extremely relevant due to the past and current co‐eruptions at both Mauna Loa and Kīlauea. The Big Island of Hawaiʻi is one of the most seismically monitored volcanic systems in the world, and recent investigations of the Big Island suggest a widespread subsurface connectivity between volcanoes. Volcanic activity has the potential
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Hydrogeological controls on microbial activity and habitability in the Precambrian continental crust Geobiology (IF 3.7) Pub Date : 2024-03-06 Min Song, Oliver Warr, Jon Telling, Barbara Sherwood Lollar
Earth's deep continental subsurface is a prime setting to study the limits of life's relationship with environmental conditions and habitability. In Precambrian crystalline rocks worldwide, deep ancient groundwaters in fracture networks are typically oligotrophic, highly saline, and locally inhabited by low‐biomass communities in which chemolithotrophic microorganisms may dominate. Periodic opening
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Enameloid-bound δ15N reveals large trophic separation among Late Cretaceous sharks in the northern Gulf of Mexico Geobiology (IF 3.7) Pub Date : 2024-01-30 Chelsea M. Comans, Sandi M. Smart, Emma R. Kast, YueHan Lu, Tina Lüdecke, Jennifer N. Leichliter, Daniel M. Sigman, Takehito Ikejiri, Alfredo Martínez-García
The nitrogen isotopic composition (15N/14N ratio, or δ15N) of enameloid-bound organic matter (δ15NEB) in shark teeth was recently developed to investigate the biogeochemistry and trophic structures (i.e., food webs) of the ancient ocean. Using δ15NEB, we present the first nitrogen isotopic evidence for trophic differences between shark taxa from a single fossil locality. We analyze the teeth of four
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Dissolved silica affects the bulk iron redox state and recrystallization of minerals generated by photoferrotrophy in a simulated Archean ocean Geobiology (IF 3.7) Pub Date : 2024-01-31 Alice Zhou, Alexis S. Templeton, Jena E. Johnson
Chemical sedimentary deposits called Banded Iron Formations (BIFs) are one of the best surviving records of ancient marine (bio)geochemistry. Many BIF precursor sediments precipitated from ferruginous, silica-rich waters prior to the Great Oxidation Event at ~2.43 Ga. Reconstructing the mineralogy of BIF precursor phases is key to understanding the coevolution of seawater chemistry and early life.
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Molecular and mineral responses of corals grown under artificial Calcite Sea conditions Geobiology (IF 3.7) Pub Date : 2024-02-02 Nicola Conci, Erika Griesshaber, Ramón E. Rivera-Vicéns, Wolfgang W. Schmahl, Sergio Vargas, Gert Wörheide
The formation of skeletal structures composed of different calcium carbonate polymorphs (e.g. aragonite and calcite) appears to be both biologically and environmentally regulated. Among environmental factors influencing aragonite and calcite precipitation, changes in seawater conditions—primarily in the molar ratio of magnesium and calcium during so-called ‘Calcite’ (mMg:mCa below 2) or ‘Aragonite’
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The illusion of balance in the history of the biosphere Geobiology (IF 3.7) Pub Date : 2024-01-12 Geerat J. Vermeij
Earth's surface has been irreversibly altered by the activity of organisms, a process that has accelerated as the power of the biosphere (the rate at which life extracts and deploys energy) has increased over time. This trend is incompatible with the expectation that the inputs to Earth's surface of life's materials from the crust and mantle be matched by export from Earth's surface to long-term reservoirs
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New keratose sponges after the end-Permian extinction provide insights into biotic recoveries Geobiology (IF 3.7) Pub Date : 2023-12-27 Siqi Wu, Joachim Reitner, David A. T. Harper, Jianxin Yu, Zhong-Qiang Chen
We challenge the prevailing view that the end-Permian extinction impeded the Triassic evolution of sponges. Here, we report a deep-water community dominated by abundant keratose sponges in the lowest Triassic strata from Southwest China. The sponge fossils occur as dark elliptical imprints in mudstone with distinct oscula on their tops. The structure of preserved fibers suggests closest affinity with
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Deep subsurface microbial life in impact-altered Late Paleozoic granitoid rocks from the Chicxulub impact crater Geobiology (IF 3.7) Pub Date : 2023-12-27 Sohaib Naseer Quraish, Charles Cockell, Cornelia Wuchter, David Kring, Kliti Grice, Marco J. L. Coolen
In 2016, IODP-ICDP Expedition 364 recovered an 829-meter-long core within the peak ring of the Chicxulub impact crater (Yucatán, Mexico), allowing us to investigate the post-impact recovery of the heat-sterilized deep continental microbial biosphere at the impact site. We recently reported increased cell biomass in the impact suevite, which was deposited within the first few hours of the Cenozoic,
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Fossilized giant sulfide-oxidizing bacteria from the Devonian Hollard Mound seep deposit, Morocco Geobiology (IF 3.7) Pub Date : 2023-12-07 Daniel Smrzka, Jennifer Zwicker, Heide Schulz-Vogt, Crispin T. S. Little, Max Rieder, Patrick Meister, Susanne Gier, Jörn Peckmann
The giant sulfide-oxidizing bacteria are particularly prone to preservation in the rock record, and their fossils have been identified in ancient phosphorites, cherts, and carbonates. This study reports putative spherical fossils preserved in the Devonian Hollard Mound hydrocarbon-seep deposit. Based on petrographical, mineralogical, and geochemical evidence the putative microfossils are interpreted
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Microbial mats and their palaeoenvironmental analysis in offshore – shelf facies of the Los Molles Formation (Toarcian – Lower Callovian) in the Chacay Melehue area, Neuquén Basin, Argentina Geobiology (IF 3.7) Pub Date : 2023-11-22 Maximiliano Nicolás Rodriguez, Débora Mical Campetella, Noelia Beatriz Carmona, Juan José Ponce, Martín Nazareno Parada
This contribution presents the first study focused on the analysis of microbial mats in the Los Molles Formation (Toarcian – Early Callovian), Neuquén Basin, Argentina. This unit mainly represents offshore-to-shelf environments affected by storms and density currents. The Los Molles Formation is one of the oldest source rocks in the Neuquén Basin and constitutes an unconventional shale gas reservoir
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Contrasting morphology and growth habits of Frutexites in Late Devonian reef complexes of the Canning Basin, northwestern Australia Geobiology (IF 3.7) Pub Date : 2023-11-20 France Champenois, Annette D. George, Kenneth J. McNamara, Jeremy Shaw, Maria Cherdantseva
Frutexites-like microstructures are described from the exhumed Late Devonian reef complexes of the northern Canning Basin, Western Australia. Several high-resolution imaging techniques, including X-ray microcomputerised tomography, scanning electron microscopy and X-ray fluorescence microscopy, were used to investigate morphology and composition in two samples. Three types of Frutexites-like microstructures
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Distinctive microfossil supports early Paleoproterozoic rise in complex cellular organisation Geobiology (IF 3.7) Pub Date : 2023-10-06 Erica V. Barlow, Christopher H. House, Ming-Chang Liu, Maxwell T. Wetherington, Martin J. Van Kranendonk
The great oxidation event (GOE), ~2.4 billion years ago, caused fundamental changes to the chemistry of Earth's surface environments. However, the effect of these changes on the biosphere is unknown, due to a worldwide lack of well-preserved fossils from this time. Here, we investigate exceptionally preserved, large spherical aggregate (SA) microfossils permineralised in chert from the c. 2.4 Ga Turee
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Divergence time estimates for the hypoxia-inducible factor-1 alpha (HIF1α) reveal an ancient emergence of animals in low-oxygen environments Geobiology (IF 3.7) Pub Date : 2023-09-26 Flavia A. Belato, Beatriz Mello, Christopher J. Coates, Kenneth M. Halanych, Federico D. Brown, André C. Morandini, Juliana de Moraes Leme, Ricardo I. F. Trindade, Elisa Maria Costa-Paiva
Unveiling the tempo and mode of animal evolution is necessary to understand the links between environmental changes and biological innovation. Although the earliest unambiguous metazoan fossils date to the late Ediacaran period, molecular clock estimates agree that the last common ancestor (LCA) of all extant animals emerged ~850 Ma, in the Tonian period, before the oldest evidence for widespread ocean
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The role of clay minerals in the preservation of Precambrian organic-walled microfossils Geobiology (IF 3.7) Pub Date : 2023-09-19 C. R. Woltz, R. P. Anderson, N. J. Tosca, S. M. Porter
Precambrian organic-walled microfossils (OWMs) are primarily preserved in mudstones and shales that are low in total organic carbon (TOC). Recent work suggests that high TOC may hinder OWM preservation, perhaps because it interferes with chemical interactions involving certain clay minerals that inhibit the decay of microorganisms. To test if clay mineralogy controls OWM preservation, and if TOC moderates
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Sulfur disproportionating microbial communities in a dynamic, microoxic-sulfidic karst system Geobiology (IF 3.7) Pub Date : 2023-09-18 Heidi S. Aronson, Christian E. Clark, Douglas E. LaRowe, Jan P. Amend, Lubos Polerecky, Jennifer L. Macalady
Biogeochemical sulfur cycling in sulfidic karst systems is largely driven by abiotic and biological sulfide oxidation, but the fate of elemental sulfur (S0) that accumulates in these systems is not well understood. The Frasassi Cave system (Italy) is intersected by a sulfidic aquifer that mixes with small quantities of oxygen-rich meteoric water, creating Proterozoic-like conditions and supporting
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Microbial diversity and authigenic siderite mediation in sediments surrounding the Kedr-1 mud volcano, Lake Baikal Geobiology (IF 3.7) Pub Date : 2023-09-12 Anna V. Lomakina, Sergei V. Bukin, Tatyana V. Pogodaeva, Alexandra V. Turchyn, Oleg M. Khlystov, Andrey V. Khabuev, Vyacheslav G. Ivanov, Aleksey A. Krylov, Tamara I. Zemskaya
The gas hydrate-bearing structure—mud volcano Kedr-1 (Lake Baikal, southern basin)—is located near the coal-bearing sediments of the Tankhoy formation of Oligocene–Miocene age and can be an ideal source of gas-saturated fluid. A significant amount of siderite minerals (FeCO3) were collected from sediments at depths ranging from 0.5 to 327 cm below the lake floor (cmblf). An important feature of these
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Evolution of iron and oxygen biogeochemical cycles during the Precambrian Geobiology (IF 3.7) Pub Date : 2023-08-25 Yasuto Watanabe, Eiichi Tajika, Kazumi Ozaki
Iron (Fe) is an essential element for life, and its geochemical cycle is intimately linked to the coupled history of life and Earth's environment. The accumulated geologic records indicate that ferruginous waters existed in the Precambrian oceans not only before the first major rise of atmospheric O2 levels (Great Oxidation Event; GOE) during the Paleoproterozoic, but also during the rest of the Proterozoic
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White and green rust chimneys accumulate RNA in a ferruginous chemical garden Geobiology (IF 3.7) Pub Date : 2023-08-24 Vanessa Helmbrecht, Maximilian Weingart, Frieder Klein, Dieter Braun, William D. Orsi
Mechanisms of nucleic acid accumulation were likely critical to life's emergence in the ferruginous oceans of the early Earth. How exactly prebiotic geological settings accumulated nucleic acids from dilute aqueous solutions, is poorly understood. As a possible solution to this concentration problem, we simulated the conditions of prebiotic low-temperature alkaline hydrothermal vents in co-precipitation
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Tocopherols and associated derivatives track the phytoplanktonic response to evolving pelagic redox conditions spanning Oceanic Anoxic Event 2 Geobiology (IF 3.7) Pub Date : 2023-08-11 Gregory T. Connock, Xiao-Lei Liu
Tocopherols serve a critical role as antioxidants inhibiting lipid peroxidation in photosynthetic organisms, yet are seldom used in geobiological investigations. The ubiquity of tocopherols in all photosynthetic lifeforms is often cited as an impediment to any diagnostic paleoenvironmental potential, while the inability to readily analyze these compounds via conventional methods, such as gas chromatography–mass
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Lipid biomarkers recording marine microbial community structure changes through the Frasnian-Famennian mass extinction event Geobiology (IF 3.7) Pub Date : 2023-07-16 Jian Chen, Nicholas Hogancamp, Man Lu, Takehito Ikejiri, Natalia Malina, Ann Ojeda, YongGe Sun, YueHan Lu
Studying the response and recovery of marine microbial communities during mass extinction events provides an evolutionary window through which to understand the adaptation and resilience of the marine ecosystem in the face of significant environmental disturbances. The goal of this study is to reconstruct changes in the marine microbial community structure through the Late Devonian Frasnian-Famennian
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Major contribution of sulfide-derived sulfur to the benthic food web in a large freshwater lake Geobiology (IF 3.7) Pub Date : 2023-07-11 Yuji Onishi, Toshiro Yamanaka, Keisuke Koba
In freshwater systems, contributions of chemosynthetic products by sulfur-oxidizing bacteria in sediments as nutritional resources in benthic food webs remain unclear, even though chemosynthetic products might be an important nutritional resource for benthic food webs in deep-sea hydrothermal vents and shallow marine systems. To study geochemical aspects of this trophic pathway, we sampled sediment
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Fire activity across Cretaceous/Paleogene transition: Evidence from pyrogenic biomarkers preserved in the Mahadeo-Cherrapunji section, Meghalaya, India Geobiology (IF 3.7) Pub Date : 2023-06-13 Sucharita Pal, Jaya Prakash Shrivastava, Munnuru Singamshetty Kalpana
Previous studies on high concentrations of polycyclic aromatic hydrocarbon (PAHs) present in the shallow-marine Um-Sohryngkew River (USR) Cretaceous/Paleogene Boundary (KPB) section suggested regional fire incidences and biotic stress on life. However, such observations at the USR site have not been confirmed so far anywhere else in the region, we, therefore, do not know whether the signal was local
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Organic-rich bimineralic ooids record biological processes in Shark Bay, Western Australia Geobiology (IF 3.7) Pub Date : 2023-05-24 Juliet Y. F. Ramey-Lariviere, Jian Gong, Matthew J. Baldes, Nilanjan Chatterjee, Tanja Bosak, Sara B. Pruss
Marine ooids have formed in microbially colonized environments for billions of years, but the microbial contributions to mineral formation in ooids continue to be debated. Here we provide evidence of these contributions in ooids from Carbla Beach, Shark Bay, Western Australia. Dark 100–240 μm diameter ooids from Carbla Beach contain two different carbonate minerals. These ooids have 50–100 μm-diameter
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Isotopic evidence of environmental changes during the Devonian–Carboniferous transition in South China and its implications for the biotic crisis Geobiology (IF 3.7) Pub Date : 2023-05-17 Hansheng Cao, Liumei Hu, Zaiyun Wang, Wentong He, Fajin Chen, Qinghua Hou, Chunqing Chen
The Devonian–Carboniferous (D–C) transition coincides with the Hangenberg Crisis, carbon isotope anomalies, and the enhanced preservation of organic matter associated with marine redox fluctuations. The proposed driving factors for the biotic extinction include variations in the eustatic sea level, paleoclimate fluctuation, climatic conditions, redox conditions, and the configuration of ocean basins
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Environmental and temporal patterns in bioturbation in the Cambrian–Ordovician of Western Newfoundland Geobiology (IF 3.7) Pub Date : 2023-05-17 Lidya G. Tarhan, Rhiannon Z. Nolan, Sophie Westacott, Jack O. Shaw, Sara B. Pruss
The early Paleozoic emergence of bioturbating (sediment-dwelling and -mixing) animals has long been assumed to have led to substantial changes in marine biogeochemistry, seafloor ecology, and the preservation potential of both sedimentary and fossil archives. However, the timing of the rise of bioturbation and environmental patterns in its expansion have long been subjects of debate—resolution of which
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Widespread seafloor anoxia during generation of the Ediacaran Shuram carbon isotope excursion Geobiology (IF 3.7) Pub Date : 2023-05-08 Chadlin M. Ostrander, Christian J. Bjerrum, Anne-Sofie C. Ahm, Simon R. Stenger, Kristin D. Bergmann, Mohamed A. K. El-Ghali, Abdul R. Harthi, Zayana Aisri, Sune G. Nielsen
Reconstructing the oxygenation history of Earth's oceans during the Ediacaran period (635 to 539 million years ago) has been challenging, and this has led to a polarizing debate about the environmental conditions that played host to the rise of animals. One focal point of this debate is the largest negative inorganic C-isotope excursion recognized in the geologic record, the Shuram excursion, and whether
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Microbial influence on dolomite and authigenic clay mineralisation in dolocrete profiles of NW Australia Geobiology (IF 3.7) Pub Date : 2023-03-27 Caroline C. Mather, Heta M. Lampinen, Maurice Tucker, Matthias Leopold, Shawan Dogramaci, Mark Raven, Robert J. Gilkes
Dolomite (CaMg(CO3)2) precipitation is kinetically inhibited at surface temperatures and pressures. Experimental studies have demonstrated that microbial extracellular polymeric substances (EPS) as well as certain clay minerals may catalyse dolomite precipitation. However, the combined association of EPS with clay minerals and dolomite and their occurrence in the natural environment are not well documented
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Biogeochemical transformations after the emergence of oxygenic photosynthesis and conditions for the first rise of atmospheric oxygen Geobiology (IF 3.7) Pub Date : 2023-03-24 Yasuto Watanabe, Eiichi Tajika, Kazumi Ozaki
The advent of oxygenic photosynthesis represents the most prominent biological innovation in the evolutionary history of the Earth. The exact timing of the evolution of oxygenic photoautotrophic bacteria remains elusive, yet these bacteria profoundly altered the redox state of the ocean–atmosphere–biosphere system, ultimately causing the first major rise in atmospheric oxygen (O2)—the so-called Great
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Mineralogical characterization of biosilicas versus geological analogs Geobiology (IF 3.7) Pub Date : 2023-02-27 Gabriela A. Farfan, David A. McKeown, Jeffrey E. Post
Non-crystalline silica mineraloids are essential to life on Earth as they provide architectural structure to dominant primary producers, such as plants and phytoplankton, as well as to protists and sponges. Due to the difficulty in characterizing and quantifying the structure of highly disordered X-ray amorphous silica, relatively little has been done to understand the mineralogy of biogenic silica
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Bioavailability of mineral-associated trace metals as cofactors for nitrogen fixation by Azotobacter vinelandii Geobiology (IF 3.7) Pub Date : 2023-02-27 Shreya Srivastava, Hailiang Dong, Oliver Baars, Yizhi Sheng
Life on Earth depends on N2-fixing microbes to make ammonia from atmospheric N2 gas by the nitrogenase enzyme. Most nitrogenases use Mo as a cofactor; however, V and Fe are also possible. N2 fixation was once believed to have evolved during the Archean-Proterozoic times using Fe as a cofactor. However, δ15N values of paleo-ocean sediments suggest Mo and V cofactors despite their low concentrations
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The role of iron in the formation of Ediacaran ‘death masks’ Geobiology (IF 3.7) Pub Date : 2023-02-26 Brandt M. Gibson, James D. Schiffbauer, Adam F. Wallace, Simon A. F. Darroch
The Ediacara biota are an enigmatic group of Neoproterozoic soft-bodied fossils that mark the first major radiation of complex eukaryotic and macroscopic life. These fossils are thought to have been preserved via pyritic “death masks” mediated by seafloor microbial mats, though little about the chemical constraints of this preservational pathway is known, in particular surrounding the role of bioavailable
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Ediacaran–Cambrian bioturbation did not extensively oxygenate sediments in shallow marine ecosystems Geobiology (IF 3.7) Pub Date : 2023-02-22 Alison T. Cribb, Sebastiaan J. van de Velde, William M. Berelson, David J. Bottjer, Frank A. Corsetti
The radiation of bioturbation during the Ediacaran–Cambrian transition has long been hypothesized to have oxygenated sediments, triggering an expansion of the habitable benthic zone and promoting increased infaunal tiering in early Paleozoic benthic communities. However, the effects of bioturbation on sediment oxygen are underexplored with respect to the importance of biomixing and bioirrigation, two
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Terrestrial surface stabilisation by modern analogues of the earliest land plants: A multi-dimensional imaging study Geobiology (IF 3.7) Pub Date : 2023-02-13 Ria L. Mitchell, Paul Kenrick, Silvia Pressel, Jeff Duckett, Christine Strullu-Derrien, Neil Davies, William J. McMahon, Rebecca Summerfield
The evolution of the first plant-based terrestrial ecosystems in the early Palaeozoic had a profound effect on the development of soils, the architecture of sedimentary systems, and shifts in global biogeochemical cycles. In part, this was due to the evolution of complex below-ground (root-like) anchorage systems in plants, which expanded and promoted plant–mineral interactions, weathering, and resulting
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A carbonate corrosion experiment at a marine methane seep: The role of aerobic methanotrophic bacteria Geobiology (IF 3.7) Pub Date : 2023-02-12 Alexmar Cordova-Gonzalez, Daniel Birgel, Max Wisshak, Tim Urich, Florian Brinkmann, Yann Marcon, Gerhard Bohrmann, Jörn Peckmann
Methane seeps are typified by the formation of authigenic carbonates, many of which exhibit corrosion surfaces and secondary porosity believed to be caused by microbial carbonate dissolution. Aerobic methane oxidation and sulfur oxidation are two processes capable of inducing carbonate corrosion at methane seeps. Although the potential of aerobic methanotrophy to dissolve carbonate was confirmed in
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Astronomically controlled deep-sea life in the Late Cretaceous reconstructed from ultra-high-resolution inoceramid shell archives Geobiology (IF 3.7) Pub Date : 2023-02-09 Adam Wierzbicki, Erik Wolfgring, Michael Wagreich, Mariusz Kędzierski, Regina Mertz-Kraus
The periodicity of the mutual position of celestial bodies in the Earth-Moon-Sun system is crucial to the functioning of life on Earth. Biological rhythms affect most of the processes inside organisms, and some can be recorded in skeletal remains, allowing one to reconstruct the cycles that occur in nature deep in time. In the present study, we have used ultra-high-resolution elemental ratio scans
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Revisiting marine redox conditions during the Ediacaran Shuram carbon isotope excursion Geobiology (IF 3.7) Pub Date : 2023-02-08 Zheng Gong, Guang-Yi Wei, Mojtaba Fakhraee, Lewis J. Alcott, Lei Jiang, Mingyu Zhao, Noah J. Planavsky
The Neoproterozoic carbonate record contains multiple carbon isotope anomalies, which are the subject of intense debate. The largest of these anomalies, the Shuram excursion (SE), occurred in the mid-Ediacaran (~574–567 Ma). Accurately reconstructing marine redox landscape is a clear path toward making sense of the mechanism that drives this δ13C anomaly. Here, we report new uranium isotopic data from
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Protracted oxygenation across the Cambrian–Ordovician transition: A key initiator of the Great Ordovician Biodiversification Event? Geobiology (IF 3.7) Pub Date : 2023-01-26 Nevin P. Kozik, Seth A. Young, Anders Lindskog, Per Ahlberg, Jeremy D. Owens
Fluctuations in marine oxygen concentrations have been invoked as a primary driver for changes in biodiversity throughout Earth history. Expansions in reducing marine conditions are commonly invoked as key causal mechanisms for mass extinctions, while increases in marine oxygenation are becoming an increasingly common causal mechanism invoked for biodiversification events. Here we utilize a multiproxy
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Organic preservation of vase-shaped microfossils from the late Tonian Chuar Group, Grand Canyon, Arizona, USA Geobiology (IF 3.7) Pub Date : 2023-01-18 Kelly E. Tingle, Susannah M. Porter, Morgan R. Raven, Andrew D. Czaja, Samuel M. Webb, Bonnie Bloeser
Vase-shaped microfossils (VSMs) are found globally in middle Neoproterozoic (800–730 Ma) marine strata and represent the earliest evidence for testate (shell-forming) amoebozoans. VSM tests are hypothesized to have been originally organic in life but are most commonly preserved as secondary mineralized casts and molds. A few reports, however, suggest possible organic preservation. Here, we test the
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Iron-mediated anaerobic ammonium oxidation recorded in the early Archean ferruginous ocean Geobiology (IF 3.7) Pub Date : 2023-01-13 Alice Pellerin, Christophe Thomazo, Magali Ader, Johanna Marin-Carbonne, Julien Alleon, Emmanuelle Vennin, Axel Hofmann
The nitrogen isotopic composition of organic matter is controlled by metabolic activity and redox speciation and has therefore largely been used to uncover the early evolution of life and ocean oxygenation. Specifically, positive δ15N values found in well-preserved sedimentary rocks are often interpreted as reflecting the stability of a nitrate pool sustained by water column partial oxygenation. This
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Effects of RuBisCO and CO2 concentration on cyanobacterial growth and carbon isotope fractionation Geobiology (IF 3.7) Pub Date : 2023-01-05 Amanda K. Garcia, Mateusz Kędzior, Arnaud Taton, Meng Li, Jodi N. Young, Betül Kaçar
Carbon isotope biosignatures preserved in the Precambrian geologic record are primarily interpreted to reflect ancient cyanobacterial carbon fixation catalyzed by Form I RuBisCO enzymes. The average range of isotopic biosignatures generally follows that produced by extant cyanobacteria. However, this observation is difficult to reconcile with several environmental (e.g., temperature, pH, and CO2 concentrations)
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Multiple sulphur isotope record of Paleoarchean sedimentary rocks across the Onverwacht Group, Barberton Greenstone Belt, South Africa Geobiology (IF 3.7) Pub Date : 2022-12-26 Eugene G. Grosch, Nicola McLoughlin, Martin Whitehouse
This study presents multiple sulphur isotope (32S, 33S, 34S, 36S) data on pyrites from silicified volcano-sedimentary rocks of the Paleoarchean Onverwacht Group of the Barberton greenstone belt, South Africa. These rocks include seafloor cherts and felsic conglomerates that were deposited in shallow marine environments preserving a record of atmospheric and biogeochemical conditions on the early Earth
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Carbon pump dynamics and limited organic carbon burial during OAE1a Geobiology (IF 3.7) Pub Date : 2022-12-25 Kohen W. Bauer, N. Ryan McKenzie, Cinzia Bottini, Elisabetta Erba, Sean A. Crowe
Oceanic Anoxic Events (OAEs) are conspicuous intervals in the geologic record that are associated with the deposition of organic carbon (OC)-rich marine sediment, linked to extreme biogeochemical perturbations, and characterized by widespread ocean deoxygenation. Mechanistic links between the marine biological carbon pump (BCP), redox conditions, and organic carbon burial during OAEs, however, remain
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Nickel and zinc micronutrient availability in Phanerozoic oceans Geobiology (IF 3.7) Pub Date : 2022-12-19 Tim C. Sweere, Alexander J. Dickson, Derek Vance
Nickel and zinc are both bio-essential micronutrients with a nutrient-like distribution in the modern ocean, but show key differences in their biological functions and geochemical behavior. Eukaryotic phytoplankton, and especially diatoms, have high Zn quotas, whereas cyanobacteria generally require relatively more Ni. Secular changes in the relative availability of these micronutrients may, therefore
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The diagenetic fate of collagen as revealed by analytical pyrolysis of fossil fish scales from deep time Geobiology (IF 3.7) Pub Date : 2022-12-18 Raman Umamaheswaran, Suryendu Dutta, Guntupalli V. R. Prasad, Mahasin Ali Khan, Sumit Kumar, Subir Bera, Rajeev Patnaik
The mechanism of protein degradation has remained a topic of debate (specifically concerning their preservation in deep time), which has recently been invigorated due to multiple published reports of preservation ranging from Miocene to the Triassic that potentially challenge the convention that protein preservation beyond the Cenozoic is extremely uncommon or is expected to be absent altogether, and
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Microbial biosignatures in ancient deep-sea hydrothermal sulfides Geobiology (IF 3.7) Pub Date : 2022-12-16 Eric Alexander Runge, Muammar Mansor, Andreas Kappler, Jan-Peter Duda
Deep-sea hydrothermal systems provide ideal conditions for prebiotic reactions and ancient metabolic pathways and, therefore, might have played a pivotal role in the emergence of life. To understand this role better, it is paramount to examine fundamental interactions between hydrothermal processes, non-living matter, and microbial life in deep time. However, the distribution and diversity of microbial
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A sedimentary record of the evolution of the global marine phosphorus cycle Geobiology (IF 3.7) Pub Date : 2022-12-05 Noah J. Planavsky, Dan Asael, Alan D. Rooney, Leslie J. Robbins, Benjamin C. Gill, Carol M. Dehler, Devon B. Cole, Susannah M. Porter, Gordon D. Love, Kurt O. Konhauser, Christopher T. Reinhard
Phosphorus (P) is typically considered to be the ultimate limiting nutrient for Earth's biosphere on geologic timescales. As P is monoisotopic, its sedimentary enrichment can provide some insights into how the marine P cycle has changed through time. A previous compilation of shale P enrichments argued for a significant change in P cycling during the Ediacaran Period (635–541 Ma). Here, using an updated
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Active and dormant microorganisms on glacier surfaces Geobiology (IF 3.7) Pub Date : 2022-11-30 James A. Bradley, Christopher B. Trivedi, Matthias Winkel, Rey Mourot, Stefanie Lutz, Catherine Larose, Christoph Keuschnig, Eva Doting, Laura Halbach, Athanasios Zervas, Alexandre M. Anesio, Liane G. Benning
Glacier and ice sheet surfaces host diverse communities of microorganisms whose activity (or inactivity) influences biogeochemical cycles and ice melting. Supraglacial microbes endure various environmental extremes including resource scarcity, frequent temperature fluctuations above and below the freezing point of water, and high UV irradiance during summer followed by months of total darkness during
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Using thermodynamics to obtain geochemical information from genomes Geobiology (IF 3.7) Pub Date : 2022-11-14 Jeffrey M. Dick, Grayson M. Boyer, Peter A. Canovas, Everett L. Shock
Thermodynamic characterization of the relative stabilities of chemical compounds is a pillar of conceptual models in various fields of geosciences. Analogous models applied to genomes can yield new information about the relationship between genomes and their geochemical environments. In this perspective article, we present a chemical and thermodynamic analysis of prokaryotic lineages that have been
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Reduction in animal abundance and oxygen availability during and after the end-Triassic mass extinction Geobiology (IF 3.7) Pub Date : 2022-11-03 Pulkit Singh, Wanyi Lu, Zunli Lu, Adam B. Jost, Kimberly Lau, Aviv Bachan, Bas van de Schootbrugge, Jonathan L. Payne
The end-Triassic biodiversity crisis was one of the most severe mass extinctions in the history of animal life. However, the extent to which the loss of taxonomic diversity was coupled with a reduction in organismal abundance remains to be quantified. Further, the temporal relationship between organismal abundance and local marine redox conditions is lacking in carbonate sections. To address these
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A re-examination of the mechanism of whiting events: A new role for diatoms in Fayetteville Green Lake (New York, USA) Geobiology (IF 3.7) Pub Date : 2022-11-03 Chloe Stanton, Ben Davis Barnes, Lee R. Kump, Julie Cosmidis
Whiting events—the episodic precipitation of fine-grained suspended calcium carbonates in the water column—have been documented across a variety of marine and lacustrine environments. Whitings likely are a major source of carbonate muds, a constituent of limestones, and important archives for geochemical proxies of Earth history. While several biological and physical mechanisms have been proposed to
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A review of microbial-environmental interactions recorded in Proterozoic carbonate-hosted chert Geobiology (IF 3.7) Pub Date : 2022-10-21 Kelsey R. Moore, Mirna Daye, Jian Gong, Kenneth Williford, Kurt Konhauser, Tanja Bosak
The record of life during the Proterozoic is preserved by several different lithologies, but two in particular are linked both spatially and temporally: chert and carbonate. These lithologies capture a snapshot of dominantly peritidal environments during the Proterozoic. Early diagenetic chert preserves some of the most exceptional Proterozoic biosignatures in the form of microbial body fossils and