Article
Geochemistry & Geophysics
A. J. Davies, U. Brand, M. Tagliavento, M. A. Bitner, D. Bajnai, P. Staudigel, M. Bernecker, J. Fiebig
Summary: The stable oxygen and clumped isotope composition of brachiopod calcite are important proxies for reconstructing Phanerozoic seawater temperatures and δ18O values. However, the shells of brachiopods precipitate out of isotopic equilibrium with ambient seawater, and the origins of this disequilibrium effect have been unclear. In this study, a dual clumped isotope thermometer is applied to modern and fossil brachiopods to investigate the disequilibrium signatures. The results show that the disequilibrium signatures are derived from the hydration/hydroxylation of CO2 and potentially the diffusion of HCO3-/CO32- in water. An empirical correction is presented to account for the disequilibrium, leading to more accurate temperature reconstructions. The dual clumped isotope thermometry method also allows for more reliable reconstructions of seawater δ18O values.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2023)
Article
Geochemistry & Geophysics
Casey P. Saenger, Andrew J. Schauer, Emma O. Heitmann, Katharine W. Huntington, Eric J. Steig
Summary: The study evaluates the assumptions made in Delta(47) measurements by analyzing Delta O-17 in reference frame materials and standards. The results show that assuming Delta O-17 = 0 can lead to overestimation or underestimation of Delta(47) values, depending on the sample's Delta O-17 relative to the working gas. This effect can introduce significant errors in reconstructed temperatures, emphasizing the importance of considering Delta O-17 for accurate Delta(47) thermometry.
Article
Geochemistry & Geophysics
Julia R. Kelson, Tyler E. Huth, Benjamin H. Passey, Naomi E. Levin, Sierra V. Petersen, Paolo Ballato, Emily J. Beverly, Daniel O. Breecker, Gregory D. Hoke, Adam M. Hudson, Haoyuan Ji, Alexis Licht, Erik J. Oerter, Jay Quade
Summary: The stable isotopic composition of pedogenic carbonates is crucial for understanding Earth's terrestrial history. By analyzing the triple oxygen isotope composition of pedogenic carbonates, this study identifies evaporation in ancient soils, which can potentially improve estimates of unevaporated waters and re-energize paleoclimate studies.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2023)
Article
Geochemistry & Geophysics
Jamie K. Lucarelli, Bettina Purgstaller, Robert N. Ulrich, Zeeshan Parvez, Albrecht Leis, Katja E. Goetschl, Robert A. Eagle, Martin Dietzel, Aradhna Tripati
Summary: The presence of amorphous precursors to minerals in laboratory materials and in nature has been observed, with implications in various disciplines. Little is known about the isotopic composition and evolution of isotopic values during the transformation of amorphous carbonates into minerals. This study investigated the evolution of isotopic values in amorphous carbonates and mineral transformation products, revealing the existence of disequilibrium isotopic compositions in the dissolved inorganic carbon pool. The results suggest the presence of a highly dynamic localized environment in biomineralizing organisms and abiotic systems. The isotopic values of carbonate minerals may not accurately represent the formation temperature.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2023)
Article
Geochemistry & Geophysics
Sarah A. Katz, Naomi E. Levin, Donald T. Rodbell, David P. Gillikin, Phoebe G. Aron, Benjamin H. Passey, Pedro M. Tapia, Analucia R. Serrepe, Mark B. Abbott
Summary: Oxygen isotope distributions in lacustrine carbonates can be used to understand climate and hydrological change. A combination of clumped (Delta 47) and triple oxygen isotope (Delta iota 17O) measurements can help identify the influences of temperature, evaporation, and precipitation on lacustrine carbonate delta 18O values. The modern calibration of this approach needs to be expanded to different climatic and hydrologic conditions for paleoclimate reconstructions.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Article
Behavioral Sciences
Alyssa M. Bohart, Nicholas J. Lunn, Andrew E. Derocher, David McGeachy
Summary: Migration of polar bears is influenced by climate change, with decreasing ice concentration impacting their access to prey and movement patterns. Continued monitoring is crucial to understanding the environmental variables affecting their migration behavior.
BEHAVIORAL ECOLOGY
(2021)
Article
Geochemistry & Geophysics
Emily J. Beverly, Naomi E. Levin, Benjamin H. Passey, Phoebe G. Aron, Drake A. Yarian, Mara Page, Elise M. Pelletier
Summary: The study investigates the relationship between Delta'O-17 in soil carbonates and soil water evaporation, finding that in arid climates, the variance in soil carbonate Delta'O-17 is driven by soil water evaporation, showing the potential to track paleoaridity.
EARTH AND PLANETARY SCIENCE LETTERS
(2021)
Article
Geochemistry & Geophysics
Joji Uchikawa, Sang Chen, John M. Eiler, Jess F. Adkins, Richard E. Zeebe
Summary: This study investigates the abundance of O-18 isotopes and C-13-O-18 isotopic clumps in carbonate minerals for inferring mineral formation temperatures. It reveals that isotopic equilibrium during mineral formation is not always achieved. Analyzing inorganic BaCO3 samples precipitated at different times, it was found that while the timescales for delta O-18 and Delta(47) equilibrium are similar, the equilibration trajectories are notably different, possibly due to differences in exchange rates for oxygen isotopes bound to C-12 versus C-13.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2021)
Article
Geology
Megan E. Smith, Donald F. McNeill, Sean T. Murray, Peter K. Swart
Summary: Carbonate concretions from the Dominican Republic provide an opportunity to study isotopic variations and environmental conditions during concretion growth. A multi-isotope approach was used to evaluate three concretions from the Cibao Basin, revealing differences in growth mechanisms and environmental changes. The study also showed potential disequilibrium effects and cautioned about the influence of multiple processes on concretion signals.
Article
Geosciences, Multidisciplinary
Daniel E. Ibarra, Tyler Kukla, Katharina A. Methner, Andreas Mulch, C. Page Chamberlain
Summary: Triple oxygen isotope measurements are used in this study for reconstructing past elevations. Analysis on lacustrine sediments from the Eocene North American Cordillera reveals trends in lake water evaporation and temperature variation, indicating the presence of a relatively high plateau in the mid-Eocene Elko Basin.
FRONTIERS IN EARTH SCIENCE
(2021)
Article
Geochemistry & Geophysics
James M. Watkins, Laurent S. Devriendt
Summary: The disequilibrium between Earth surface carbonates and the surrounding solution complicates the use of stable isotopes in paleoenvironment reconstructions. A box model is developed to describe the isotopic effects in the CaCO3-DIC-H2O system and is validated using experimental data. The model can be applied to various situations involving CO2 absorption, degassing, and mixing with other dissolved inorganic carbon sources.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2022)
Article
Environmental Sciences
Matthew H. H. Long, Jordan W. Mora
Summary: Coastal nutrient pollution, or eutrophication, often occurs due to human activities in terrestrial watersheds, leading to degraded water quality over time. The management and monitoring of estuarine systems usually lag behind environmental degradation. In the case of Waquoit Bay National Estuarine Research Reserve, the loss of eelgrass meadows and the decline in macroalgal biomass have resulted in shifts in water quality and ecosystem structure, with an increase in phytoplankton biomass and a shift towards pelagic dominance. This shift may have wider implications for other eutrophic and warming estuaries in the future.
ESTUARIES AND COASTS
(2023)
Article
Biodiversity Conservation
Eric Regehr, Markus Dyck, Samuel Iverson, David S. Lee, Nicholas J. Lunn, Joseph M. Northrup, Marie-Claude Richer, Guillaume Szor, Michael C. Runge
Summary: Arctic marine mammals are important subsistence resources for Indigenous people, with a focus on understanding the impacts of climate change on sea-ice loss and harvesting activities for ice-dependent species like polar bears. A demographic model was developed for polar bears in Southern Hudson Bay, Canada, using Bayesian methods to estimate parameters and inform a harvest management strategy. The study showed that under different environmental scenarios, maintaining sustainable harvest levels for polar bears requires careful consideration of female harvest rates.
BIOLOGICAL CONSERVATION
(2021)
Article
Geochemistry & Geophysics
C. W. Nooitgedacht, H. J. L. van der Lubbe, S. de Graaf, M. Ziegler, P. T. Staudigel, J. J. G. Reijmer
Summary: The distribution of oxygen isotopes between calcite and fluid inclusions is useful for reconstructing near-surface calcite precipitation temperatures, but its resilience to diagenetic oxygen isotope alteration in deep-formed calcite is poorly understood. Clumped isotopes are also vulnerable to diagenetic alteration, with post-entrapment isotope exchange potentially affecting the calcite-fluid oxygen isotope distribution and clumped isotope composition. The sensitivity of the fluid inclusion thermometer to isotopic alteration is higher than that of the clumped isotope thermometer, with the mass balance of oxygen between calcite and fluid inclusions determining their vulnerability to diagenetic overprinting.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2021)
Article
Geochemistry & Geophysics
C. W. Nooitgedacht, H. J. L. van der Lubbe, M. Ziegler, P. T. Staudigel
Summary: The study reveals that biogenic aragonite undergoes significant oxygen isotope exchange with internal water during heating, affecting the reconstruction of paleotemperatures. In contrast, inorganic aragonite does not exhibit oxygen isotope exchange, suggesting a link between internal oxygen isotope exchange and Δ(47) resetting. Water-aragonite exchange occurs at lower temperatures and may have occurred earlier during the burial of biogenic aragonites.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2021)
Article
Geology
Babatunde Olanipekun, Karem Azmy
Summary: The study indicates that the sandstone reservoir of the Tithonian Jeanne d'Arc Formation in the Terra Nova oilfield underwent early dolomite cementation and subsequent diagenetic events, playing a significant role in controlling reservoir quality. The diagenetic processes were influenced by depositional settings, with cycles of early dolomite cementation and subsequent events controlling the sandstone porosity structure and quality.
Article
Geosciences, Multidisciplinary
Guoqiang Luan, Karem Azmy, Chunmei Dong, Chengyan Lin, Lihua Ren, Changying Shi
Summary: Diagenetic carbonate cements, including sporadical siderite, dolomite, calcite 1, and massive ankerite and calcite 2, occur in Eocene turbidite lithic arkose in Niuzhuang sag, eastern China. Petrographic and geochemical investigations reveal that the formation of these carbonate cements followed a sequence of calcite 1, Ak, and calcite 2, with increasing temperature related to burial depth. Calcite 1 and calcite 2 were derived mainly from the dissolution of carbonates in calcareous shales, while ankerite showed contributions from magmatic carbon.
Article
Ecology
Sarah J. Salisbury, Gregory R. McCracken, Robert Perry, Donald Keefe, Kara K. S. Layton, Tony Kess, Cameron M. Nugent, Jong S. Leong, Ian R. Bradbury, Ben F. Koop, Moira M. Ferguson, Daniel E. Ruzzante
Summary: The genetic consequences associated with the loss of migratory capacity of landlocked diadromous fishes in freshwater are not well understood. Selective pressures in freshwater residency can lead to differentiation between landlocked and anadromous populations, as well as within landlocked populations. However, genetic drift in isolated landlocked populations may limit consistent adaptation. Understanding the genetic parallelism can have implications for evolution and management practices.
AMERICAN NATURALIST
(2022)
Article
Geology
Qian Li, Karem Azmy, Shuai Yang, Hongde Chen, Shenglin Xu, Liangbiao Lin, Zhongtang Su, Anqing Chen, Yu Yu, Fengrui Sun
Summary: The Early-Middle Permian delta C-13(carb) variations are recorded in the marine carbonates of the Luduba section. The study reveals important characteristics of the C-isotope profile and different negative C-13(carb) excursions, which can serve as important chemostratigraphic markers for comparative studies.
CARBONATES AND EVAPORITES
(2022)
Article
Ecology
Kara K. S. Layton, Ian R. Bradbury
Summary: The study proposes a broadening of genetic variant research to include structural and epigenetic variants that play important roles in adaptation, in order to improve the prediction power of species response to climate change, especially for weakly structured or panmictic species. This can help reveal the molecular mechanisms underlying species' response to climate change.
JOURNAL OF ANIMAL ECOLOGY
(2022)
Article
Geosciences, Multidisciplinary
Noel C. Shembilu, Karem Azmy
Summary: The study utilized multiple proxies to analyze the productivity, weathering products input, and paleoredox conditions of the Middle-Upper Cambrian carbonates. Positive shifts in certain geochemical profiles were associated with sea level falls and increased weathering activities, indicating changes in redox state.
MARINE AND PETROLEUM GEOLOGY
(2022)
Article
Geosciences, Multidisciplinary
Guoqiang Luan, Karem Azmy, Fabrizio Berra, Giovanna Della Porta, Mattia Nembrini
Summary: The Dorgali Formation in eastern Sardinia consists of dolomitized oolitic grainstone and exhibits a complex diagenetic history. Petrographic examinations revealed three main phases of dolomites with different crystal sizes, indicating the origin of dolomites in different burial conditions and temperatures. The geochemical characteristics of dolomitizing fluids suggest a seawater origin for the parent fluids.
MARINE AND PETROLEUM GEOLOGY
(2022)
Article
Geology
Lei Jiang, Anjiang Shen, Zichen Wang, Anping Hu, Yongsheng Wang, Xianying Luo, Feng Liang, Karem Azmy, Liyin Pan
Summary: This article examines different types of dolomite from three Neoproterozoic dolostone profiles in China and proposes a diagenetic model explaining the decrease in iron and manganese concentrations during dolomitization. The study questions the use of widespread Neoproterozoic fibrous dolomite cements in paleoclimate reconstruction and as evidence for the "dolomite sea" hypothesis.
Article
Genetics & Heredity
Nicholas W. Jeffery, Sarah J. Lehnert, Tony Kess, Kara K. S. Layton, Brendan F. Wringe, Ryan R. E. Stanley
Summary: A key component of the global blue economy strategy is the sustainable extraction of marine resources and conservation of marine environments through networks of marine protected areas. Omics approaches, such as genomics and transcriptomics, are becoming essential tools for the development and maintenance of these networks. They can assess population connectivity, evaluate genetic variation across protected areas, and characterize the full range of marine life. Omics tools play an important role in the management of marine protected areas.
FRONTIERS IN GENETICS
(2022)
Article
Environmental Sciences
Narissa Bax, David K. A. Barnes, Santiago E. A. Pineda-Metz, Tabitha Pearman, Markus Diesing, Stefanie Carter, Rachel V. Downey, Chris D. Evans, Paul Brickle, Alastair M. M. Baylis, Alyssa M. Adler, Amy Guest, Kara K. S. Layton, Paul E. Brewin, Daniel T. I. Bayley
Summary: Ecosystem-based conservation, including blue carbon habitats and carbon credit systems, can reduce greenhouse gas levels and support biodiversity and sustainable economies. However, there is limited research and policy integration at the regional level, hindering effective management. Coastal ecosystems in the South Atlantic and sub-Antarctic regions can provide valuable information for long-term ecosystem-based management.
FRONTIERS IN MARINE SCIENCE
(2022)
Article
Energy & Fuels
Guoqiang Luan, Chunmei Dong, Karem Azmy, Li-Yun Fu, Chengyan Lin, Lihua Ren, Changying Shi, Jia Li
Summary: The composition of formation waters in the Dongying Depression provides important clues about regional water-rock interactions. Chemical analysis of formation waters from different geological formations reveals two main geochemical facies: the chloride-magnesium facies and the bicarbonate-sodium facies. The salinity and pH of the water show a systematic relationship with ion concentrations, indicating thermodynamic buffering by silicate-carbonate mineral assemblages.
JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
(2022)
Article
Geology
Tianbo Yang, Karem Azmy, Zhiliang He, Shuangjian Li, Entao Liu, Shitou Wu, Jingbin Wang, Tianyi Li, Jian Gao
Summary: The mechanism of fault-controlled hydrothermal dolomitization in the southeastern Sichuan Basin is studied using petrographic, geochemical, and chronological data. The results indicate a temporal relationship between the dolomitization and the Emeishan Large Igneous Province. This study provides insights into the dolomitization process and regional tectonic activities.
SEDIMENTARY GEOLOGY
(2022)
Article
Geosciences, Multidisciplinary
Guoqiang Luan, Karem Azmy, Rudi Meyer, Babatunde Olanipekun, Chunmei Dong
Summary: This study investigates the origin of carbonate cements in the Ben Nevis sandstones through various analyses. The results suggest that these cements mainly originate from early precipitation and dissolution of bioclasts, with the involvement of organic carbon during progressive burial. The development of secondary porosity is closely related to the dissolution of calcite cements.
MARINE AND PETROLEUM GEOLOGY
(2023)
Article
Biochemistry & Molecular Biology
Sarah J. Salisbury, Robert Perry, Don Keefe, Gregory R. McCracken, Kara K. S. Layton, Tony Kess, Ian R. Bradbury, Daniel E. Ruzzante
Summary: Polymorphic species are valuable for studying diversification caused by evolutionary processes. Factors such as colonization history, selection, gene flow, and genetic drift influence morph differentiation in these species. Understanding the interaction and relative importance of these evolutionary processes is crucial for management decisions and understanding speciation. In this study, the researchers investigated how geographic distance, environmental conditions, and colonization history influenced morph migratory capacity in Arctic Charr. Their results demonstrated that gene flow, colonization history, and local adaptation interact to shape the genetic variation and evolutionary trajectory of populations.
Review
Genetics & Heredity
Kathrin Theissinger, Carlos Fernandes, Giulio Formenti, Iliana Bista, Paul R. Berg, Christoph Bleidorn, Aureliano Bombarely, Angelica Crottini, Guido R. Gallo, Jose A. Godoy, Sissel Jentoft, Joanna Malukiewicz, Alice Mouton, Rebekah A. Oomen, Sadye Paez, Per J. Palsboll, Christophe Pampoulie, Maria J. Ruiz-Lopez, Simona Secomandi, Hannes Svardal, Constantina Theofanopoulou, Jan de Vries, Ann-Marie Waldvogel, Guojie Zhang, Erich D. Jarvis, Miklos Balint, Claudio Ciofi, Robert M. Waterhouse, Camila J. Mazzoni, Jacob Hoglund
Summary: The availability of public genomic resources can greatly assist biodiversity assessment, conservation, and restoration efforts. Reference genomes play a key role in facilitating biodiversity research and conservation. Integrating the use of reference genomes as a best practice in conservation genomics is essential.
TRENDS IN GENETICS
(2023)
Article
Geochemistry & Geophysics
Zhen-Min Ge, Xiao-Long Huang, Wei Xie, Tobias W. Hofig, Fan Yang, Yang Yu, S. Khogenkumar Singh
Summary: The mantle source composition of the nascent oceanic crust in the central part of the Gulf of California has been investigated using basaltic glass samples. These samples show trace element patterns similar to enriched mid-ocean ridge basalts, suggesting that the nascent oceanic crust in the Guaymas Basin might be generated through partial melting of a depleted mantle source metasomatized by subducted slab materials.
Article
Geochemistry & Geophysics
Jean-Michel Brazier, Katja E. Goetschl, Martin Dietzel, Vasileios Mavromatis
Summary: This study estimated the distribution coefficient of Zn2+ between calcite/aragonite and reactive fluids and found that the growth rate strongly influences D-Zn(2+) in both minerals. Additionally, a linear correlation was found between D-Zn(2+) and the saturation degree of the reactive fluid.
Article
Geochemistry & Geophysics
Ming Lei, Michele Lustrino, Jifeng Xu, Zhiqiang Kang, Zhengfu Guo, Jianlin Chen
Summary: This study presents a comprehensive geochronological, mineralogical, and geochemical analysis of olivine leucitites in the Maiga area of southern Tibet, suggesting that these rocks originate from a carbonated peridotite mantle source and highlighting the possibility of carbonates being recycled deep into the mantle during continental subduction.
Article
Geochemistry & Geophysics
Yuntao Ye, Xiaomei Wang, Huajian Wang, Haifeng Fan, Zhigang Chen, Qingjun Guo, Ziteng Wang, Chaodong Wu, Donald E. Canfield, Shuichang Zhang
Summary: Phosphorus is an essential element for life and its cycle in the ocean is closely connected with the carbon and oxygen cycles. The study of phosphate oxygen isotopes can provide insights into various reactions related to phosphorus. By analyzing carbonate fluorapatite samples from the Mesoproterozoic Era in North China, it was found that the oxygen isotope values were lower compared to modern samples, indicating a warmer climate during that time period and a potential reason for the scarcity of phosphorite.
Article
Geochemistry & Geophysics
Vincent Busigny, Oanez Lebeau, Didier Jezeduel, Carine Chaduteau, Sean Crowe, Magali Ader
Summary: This study conducted high-precision Mo isotope research on hydrothermal metal sulfides from a porphyry copper deposit in Southwest China and found that different stages of mineralization have distinct Mo isotope compositions, providing valuable insights into the behavior of Mo isotopes in magmatic-hydrothermal systems.
Article
Geochemistry & Geophysics
Min Ji, Xiao-Ying Gao, Yong-Fei Zheng, Bing Gong
Summary: The study examines the anatectic mechanisms in the Himalayan orogen, finding that pressure and temperature control the reaction, while water content mainly affects the solid-phase composition. Dehydration and hydration melting likely occur at different depths in the crust. This research provides important insights into the melting processes in collisional orogens.