Article
Geosciences, Multidisciplinary
M. Janssen, L. Caracciolo, L. M. Bonnell, R. H. Lander, A. Munnecke, A. Beltran-Trivino, F. Muto, H. Stollhofen
Summary: Depositional environment, climate, diagenetic processes, and sediment composition are important factors controlling the precipitation and distribution of near-surface carbonate cements. Simulation studies show that early carbonate cementation has a significant impact on compaction behavior and porosity reduction during burial, resulting in less pore loss.
MARINE AND PETROLEUM GEOLOGY
(2023)
Article
Geology
John J. G. Reijmer
Summary: The different types of marine carbonate factories are influenced by factors such as light, temperature, and nutrients in sediment production and export, each displaying unique characteristics in response to environmental changes.
Article
Geochemistry & Geophysics
Jack G. Murphy, Anne-Sofie C. Ahm, Peter K. Swart, John A. Higgins
Summary: The records of lithium isotopic composition in seawater preserved in shallow-marine carbonate sediments are valuable for studying the links between silicate weathering, clay formation, global carbon cycle, and Earth's climate over geological time. This study presents measurements of lithium isotopic composition in Neogene shallow-marine carbonates and demonstrates the effects of mineralogy and diagenetic alteration on the variability of bulk sediment δ Li-7 values. The findings suggest that robust 'snapshots' of seawater δ Li-7 values in the past can be obtained from shallow-water marine carbonate sediments.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2022)
Article
Geochemistry & Geophysics
Sean J. Loyd, Patrick Meister, Bo Liu, Kevin Nichols, Frank A. Corsetti, Robert Raiswell, William Berelson, Graham Shields, Mark Hounslow, John W. F. Waldron, Bayne Westrick-Snapp, Jamie Hoffman
Summary: The early diagenesis of marine organic matter has a significant impact on Earth's surface chemistry, particularly in terms of carbon burial potential and the formation of authigenic minerals such as carbonate concretions. The formation of these concretions is closely related to microbial anaerobic diagenetic reactions that degrade organic matter and methane, with some reactions requiring an external oxidant. Changes in the oxidation state of Earth's oceans over time can therefore influence the mechanisms of concretion formation. Variability in the carbon isotope compositions of concretions indicates changes in diagenesis in shallow marine sediments, which is associated with the evolving redox landscape of Earth. Transport modeling helps to understand the potential effects of shifting redox chemistry and highlights the importance of organic carbon supply to the seafloor, marine sulfate concentrations, methane production, and external methane influx. The first clear evidence of anaerobic oxidation of methane-derived concretions occurred during the Carboniferous period, coinciding with the increased marine sulfate levels in the Paleozoic era. The lower variability observed in older concretions, particularly the Precambrian ones, may be attributed to a smaller marine sulfate reservoir and possibly elevated concentrations of marine dissolved inorganic carbon. The reasons behind the increase in maximum carbon isotope values over time are still not fully understood but may be related to isotopic equilibration between dissolved inorganic carbon and externally-derived methane. Ultimately, the isotopic record of concretions reflects changes in the availability of organic matter and the oxidation state of the marine environment, providing insights into the subsurface biosphere and diagenesis throughout geological time.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2023)
Article
Geosciences, Multidisciplinary
M. Ingalls, J. P. Grotzinger, T. Present, B. Rasmussen, W. W. Fischer
Summary: Phosphorus is crucial for cell biology, but it is scarce in modern marine environments due to its consumption by life or formation of apatite minerals through calcium titration. In this study, we measured the phosphate concentrations in Neoarchean carbonate facies and found that carbonates from that period were significantly enriched in carbonate-associated phosphate compared to modern marine carbonates. This suggests that early biosphere productivity was limited by electron availability rather than phosphate or other nutrients, which helps explain the central role of phosphorus in cellular molecules, metabolisms, and bioenergetics.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geochemistry & Geophysics
Giorgio Castellan, Lorenzo Angeletti, Simonepietro Canese, Claudio Mazzoli, Paolo Montagna, Stefano Schiaparelli, Marco Taviani
Summary: The study highlights the prevalence of Ca-carbonate production by marine biogenic skeletal organisms in the Antarctic seas. Video surveys conducted in two sites in the Ross Sea region reveal the widespread abundance of low-Mg and high-Mg calcite calcifiers, with evidence of coralline algae coverage on the seabed in shallow areas. This baseline data will be crucial for monitoring the response of polar biota in a rapidly changing ocean.
Article
Geochemistry & Geophysics
Sophie Graul, Toivo Kallaste, Siim Pajusaar, Kritsjan Urston, Andre Gregor, Marko Moilanen, Mawo Ndiaye, Rutt Hints
Summary: Sedimentary phosphorites in the Cambrian-Ordovician boundary beds in Estonia are abundant phosphate rock reserves with a tonnage of approximately three billion tonnes, and also potential sources of rare earth elements and yttrium. This study conducted a detailed geochemical and mineralogical investigation on the Toolse deposit, and developed a REE sequestration model based on correlation of sedimentary facies. Various analytical techniques were used for sample analysis. The results show the unique enrichment pattern of REE + Y contents in the phosphorites, and provide insights into the uptake mechanisms during transport, deposition, and early diagenesis processes.
JOURNAL OF GEOCHEMICAL EXPLORATION
(2023)
Article
Geosciences, Multidisciplinary
Jack Stacey, Ashleigh V. S. Hood, Malcolm W. Wallace
Summary: This study uses trace and rare earth element geochemistry to determine shallow marine redox conditions during the deposition of the late Tonian Devede Formation. The findings suggest that shallow marine environments during the late Tonian Period were predominantly characterized by anoxic and euxinic conditions, making them challenging habitats for complex life forms.
PRECAMBRIAN RESEARCH
(2023)
Article
Geosciences, Multidisciplinary
Andrew D. La Croix, Korhan Ayranci, Shahin E. Dashtgard
Summary: This paper summarizes the current state of knowledge regarding animal-sediment interactions in siliciclastic shallow-marine environments. It provides insights into the behaviors of organisms in different environmental conditions and their geological features. This knowledge is important for reconstructing paleo-ecosystems and explaining sedimentary strata.
EARTH-SCIENCE REVIEWS
(2022)
Article
Environmental Sciences
Guanghong Wu, Jianling Li, Wei Luo
Summary: This study used a two-year (2020-2021) survey dataset to investigate the spatial distribution of six water quality parameters in the Bohai Sea and quantify their potential sources. The results showed significant differences in spatial distribution, with terrestrial input being the main pollution source for COD, DIN, and SRP. Phosphorus-limiting conditions were observed in the Bohai Sea. High concentrations of petroleum pollutants were found in port areas, offshore oilfields, and adjacent areas. The pH in the Bohai Sea was above the global oceanic average and there were no signs of acidification. The study identified the contributions of different sources to water quality.
MARINE POLLUTION BULLETIN
(2023)
Article
Geosciences, Multidisciplinary
Baozeng Xie, Jian-ming Zhu, Xiangli Wang, Dongtao Xu, Limin Zhou, Xiqiang Zhou, Xiaoying Shi, Dongjie Tang
Summary: The availability of oxygen is crucial for the evolution of eukaryotes, but the redox conditions of the mid-Proterozoic atmospheric-oceanic system are debated. Previous studies suggested a low oxygen level in the mid-Proterozoic atmosphere, but a recent study revealed a pulsed oxygenation event associated with the earliest known multi-cellular eukaryotic fossils.
GEOLOGICAL SOCIETY OF AMERICA BULLETIN
(2023)
Article
Geochemistry & Geophysics
Michael B. Adebayo, Clara T. Bolton, Ross Marchant, Franck Bassinot, Sandrine Conrod, Thibault de Garidel-Thoron
Summary: This study used a tropical Indian Ocean core-top data set to test the Optimum size-hypothesis and investigate the relationships between planktonic foraminiferal size and environmental parameters. Results showed that most planktonic foraminifera species have unimodal size frequency distributions, with some larger species showing multimodal distributions. The study also revealed that relative abundance is not a good predictor of species' optima and within-species size response to environmental parameters is species-specific, with carbonate ion concentration, temperature, and salinity being primary drivers.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2023)
Article
Geochemistry & Geophysics
Y. Ge
Summary: Extensive early marine cementation at the seafloor has important environmental implications and its driving factors are still controversial. This study investigates multiple factors involved in early marine cementation based on analysis of the Abu Dhabi coastal area in the Persian Gulf. The results suggest that factors such as CaCO3 saturation, saturation gradient, higher sea level, and the formation of shallow redox boundary contribute to extensive early marine cementation.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2022)
Article
Geology
Phyllis Mono, Rene Hoffmann, Max Wisshak, Stephen W. Lokier, Chelsea L. Pederson, Dominik Hennhoefer, Mara R. Diaz, Peter K. Swart, Gernot Nehrke, Adrian Immenhauser
Summary: This study presents an in-depth examination of microbial bioerosion features of Holocene ooids from two locations, the Schooner Cays ooid shoals and the Shalil al Ud ooid shoals. The study finds no significant differences in ooid characteristics between the two locations and identifies the presence of various microendolithic borings. The study also proposes a four-stage model for ooid formation and highlights the importance of understanding the role of bioerosion in ooid degradation.
Article
Engineering, Environmental
Bingfeng Chen, Zhenyan Zhang, Tingzhang Wang, Hang Hu, Guoyan Qin, Tao Lu, Wenjie Hong, Jun Hu, Josep Penuelas, Haifeng Qian
Summary: We created a global map using a machine-learning model to predict marine microplastic pollution. The results showed that microplastics accumulate in subtropical gyres and near polar seas. Our study also identified areas with high microplastic pollution and high potential for biodegradation, but the limited number of samples hindered accurate predictions.
JOURNAL OF HAZARDOUS MATERIALS
(2023)
Article
Geosciences, Multidisciplinary
Alexandre Pohl, Yannick Donnadieu, Yves Godderis, Cyprien Lanteaume, Alex Hairabian, Camille Frau, Julien Michel, Marie Laugie, John J. G. Reijmer, Christopher R. Scotese, Jean Borgomano
GEOLOGICAL SOCIETY OF AMERICA BULLETIN
(2020)
Article
Paleontology
Camille Frau, William A. P. Wimbledon, Christina Ifrim, Luc G. Bulot, Alexandre Pohl
Summary: This study revises and reassesses the ammonite taxa from the Berriasian deposits in Russia, introducing a new genus and establishing a new family. It suggests excluding western Tethyan migrants in the 'Ryazanian' beds and approaching the correlation with caution.
Article
Multidisciplinary Sciences
Axelle Zacai, Claude Monnet, Alexandre Pohl, Gregory Beaugrand, Gary Mullins, David M. Kroeck, Thomas Servais
Summary: Researchers have found that the latitudinal diversity gradient (LDG) was exhibited by marine phytoplankton from the beginning of the Cambrian period, with a diversity peak centered in the Southern Hemisphere instead of the equator. This LDG is likely a truncated bimodal gradient, possibly due to uneven sediment preservation, inadequate sampling effort, and/or lower initial diversity in the Northern Hemisphere. Variation in the LDG over time is primarily attributed to fluctuations in annual sea-surface temperature and long-term climate changes.
Article
Multidisciplinary Sciences
Thomas W. Wong Hearing, Alexandre Pohl, Mark Williams, Yannick Donnadieu, Thomas H. P. Harvey, Christopher R. Scotese, Pierre Sepulchre, Alain Franc, Thijs R. A. Vandenbroucke
Summary: Contrasting hypotheses regarding Cambrian continental configuration and climate were tested, with results indicating that the Antarctocentric paleogeographic paradigm can reconcile geological data and simulated Cambrian climate. Analysis suggests a greenhouse climate during the Cambrian animal radiation period.
NATURE COMMUNICATIONS
(2021)
Article
Geosciences, Multidisciplinary
Marie Laugie, Yannick Donnadieu, Jean-Baptiste Ladant, Laurent Bopp, Christian Ethe, Francois Raisson
Summary: The study conducted numerical simulations of the Cenomanian period to understand the controls on oceanic oxygen and the initial conditions of the Oceanic Anoxic Event 2 (OAE2). It found that paleogeography and ocean circulation were crucial factors in the development of oxygen depletion, with the Central American Seaway depth playing a significant role. The research suggests that changes in paleogeography and gateways were major influencers of oceanic circulation and oxygen distribution, creating conditions necessary for the OAE2 to occur.
PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY
(2021)
Article
Geosciences, Multidisciplinary
Alexandre Pohl, Zunli Lu, Wanyi Lu, Richard G. Stockey, Maya Elrick, Menghan Li, Andre Desrochers, Yanan Shen, Ruliang He, Seth Finnegan, Andy Ridgwell
Summary: The study found evidence of seafloor anoxia during the late Ordovician glacial period, but also showed increased upper-ocean oxygenation. Through simulation studies, it was revealed that reorganization of ocean circulation during the late Ordovician altered oxygen levels in the water column, challenging previous assumptions about the relationship between climate states and oxygen levels.
Article
Geosciences, Multidisciplinary
Pierre Maffre, Yves Godderis, Alexandre Pohl, Yannick Donnadieu, Sebastien Carretier, Guillaume Le Hir
Summary: The study investigates the impact of vascular plant colonization on physical erosion and chemical weathering on continents during the Devonian. The researchers use mathematical models to simulate the response of the global carbon and alkalinity cycles and climate to the colonization phase. The findings show that the pathways of colonization have a significant impact on CO2 history, leading to different patterns of atmospheric CO2 evolution.
AMERICAN JOURNAL OF SCIENCE
(2022)
Article
Geosciences, Multidisciplinary
Anta-Clarisse Sarr, Yannick Donnadieu, Clara T. Bolton, Jean-Baptiste Ladant, Alexis Licht, Frederic Fluteau, Marie Laugie, Delphine Tardif, Guillaume Dupont-Nivet
Summary: The drivers of the evolution of the South Asian Monsoon are still debated, but Himalayan uplift, strengthening of the Somali Jet, emergence of the Arabian Peninsula, and the onset of modern-like atmospheric circulation are considered key factors.
Article
Multidisciplinary Sciences
Alexandre Pohl, Andy Ridgwell, Richard G. Stockey, Christophe Thomazo, Andrew Keane, Emmanuelle Vennin, Christopher R. Scotese
Summary: The early evolution and extinction of marine animals are influenced by changes in dissolved oxygen concentrations in the ocean, which are mainly affected by the geological history of atmospheric oxygen. However, through Earth system model experiments, it is discovered that continental rearrangement during the Phanerozoic era has led to variations in ocean oxygen levels and a decoupling in time between the upper-ocean and benthic [O-2].
Article
Multidisciplinary Sciences
Pedro Cermeno, Carmen Garcia-Comas, Alexandre Pohl, Simon Williams, Michael J. Benton, Chhaya Chaudhary, Guillaume Le Gland, R. Dietmar Mueller, Andy Ridgwell, Sergio M. Vallina
Summary: The fossil record of marine invertebrates has been used to study the limits of global diversity in the sea. Ecological theory suggests that as diversity grows, biological interactions impose limits on diversity. However, the extent to which these interactions have constrained diversity over evolutionary time remains unclear. A regional diversification model was developed to reproduce the trends in global diversity of marine invertebrates, and it was found that less than 2% of the global flooded continental area approached ecological saturation. The overall increase in global diversity was attributed to the development of diversity hotspots under stable Earth system conditions and maximum continental fragmentation.
Article
Multidisciplinary Sciences
Alexandre Pohl, Thomas Wong Hearing, Alain Franc, Pierre Sepulchre, Christopher R. Scotese
Summary: This article describes a suite of global climate model output files that provide continental climatic conditions, climate classification, and topography information for various time periods. The simulation of climatic variables was conducted using a general circulation model, taking into account paleogeography, atmospheric composition, and solar luminosity.
Article
Geosciences, Multidisciplinary
A-C Sarr, Y. Donnadieu, M. Laugie, J-B Ladant, B. Sucheras-Marx, F. Raisson
Summary: This study used an Earth System Model to simulate the cyclicity of marine sediment deposits during hothouse climate periods and found that Earth's orbit variations have a significant impact on the ocean's oxygenation state. Especially in enclosed and already poorly oxygenated basins, orbital changes can lead to up to 50% of the water volume becoming anoxic.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Multidisciplinary Sciences
Alexandre Pohl, Richard G. Stockey, Xu Dai, Ryan Yohler, Guillaume Le Hir, Dominik Huelse, Arnaud Brayard, Seth Finnegan, Andy Ridgwell
Summary: The study finds that during the Early Paleozoic, climate and continental configuration led to a much higher extinction susceptibility compared to other periods in the Phanerozoic. This higher susceptibility is mainly due to the limited geographical range of marine organisms, and it is not necessarily linked to increasing oxygenation.
Article
Multidisciplinary Sciences
Richard G. Stockey, Alexandre Pohl, Andy Ridgwell, Seth Finnegan, Erik A. Sperling
Summary: The decline in background extinction rates of marine animals through geologic time is linked to the synergistic impacts of oxygen and temperature on aerobic respiration, making marine animals more vulnerable to ocean warming events during periods of limited surface oxygenation. Physiological theory predicts that atmospheric oxygen is the dominant predictor of extinction vulnerability for marine animals.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)