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Artykuły w czasopismach na temat „Seawater signature”

Autor: Grafiati

Data publikacji: 16 listopada 2024

Data aktualizacji: 31 lipca 2025

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1

Kurzweil, Florian, Corey Archer, Martin Wille, Ronny Schoenberg, Carsten Münker, and Olaf Dellwig. "Redox control on the tungsten isotope composition of seawater." Proceedings of the National Academy of Sciences 118, no. 18 (2021): e2023544118. http://dx.doi.org/10.1073/pnas.2023544118.

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Free oxygen represents an essential basis for the evolution of complex life forms on a habitable Earth. The isotope composition of redox-sensitive trace elements such as tungsten (W) can possibly trace the earliest rise of oceanic oxygen in Earth’s history. However, the impact of redox changes on the W isotope composition of seawater is still unknown. Here, we report highly variable W isotope compositions in the water column of a redox-stratified basin (δ186/184W between +0.347 and +0.810 ‰) that contrast with the homogenous W isotope composition of the open ocean (refined δ186/184W of +0.543

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Emmanuel, S., J. A. Schuessler, J. Vinther, A. Matthews, and F. von Blanckenburg. "Iron isotope fractionation in marine invertebrates in near shore environments." Biogeosciences Discussions 11, no. 4 (2014): 5533–55. http://dx.doi.org/10.5194/bgd-11-5533-2014.

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Abstract. Chitons (Mollusca) are marine invertebrates that produce radula (teeth or rasping tongue) containing high concentrations of biomineralized magnetite and other iron bearing minerals. As Fe isotope signatures are influenced by redox processes and biological fractionation, Fe isotopes in chiton radula might be expected to provide an effective tracer of ambient oceanic conditions and biogeochemical cycling. Here, in a pilot study to measure Fe isotopes in marine invertebrates, we examine Fe isotopes in modern marine chiton radula collected from different locations in the Atlantic and Pac

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Emmanuel, S., J. A. Schuessler, J. Vinther, A. Matthews, and F. von Blanckenburg. "A preliminary study of iron isotope fractionation in marine invertebrates (chitons, Mollusca) in near-shore environments." Biogeosciences 11, no. 19 (2014): 5493–502. http://dx.doi.org/10.5194/bg-11-5493-2014.

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Abstract. Chitons (Mollusca) are marine invertebrates that produce radulae (teeth or rasping tongues) containing high concentrations of biomineralized magnetite and other iron-bearing minerals. As Fe isotope signatures are influenced by redox processes and biological fractionation, Fe isotopes in chiton radulae might be expected to provide an effective tracer of ambient oceanic conditions and biogeochemical cycling. Here, in a pilot study to measure Fe isotopes in marine invertebrates, we examine Fe isotopes in modern marine chiton radulae collected from different locations in the Atlantic and

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Renson, Virginie, and Michael D. Glascock. "Lead Isotopes to Identify Underwater Ceramic Contamination: The Example of the Kyrenia Shipwreck (Cyprus)." Minerals 11, no. 6 (2021): 625. http://dx.doi.org/10.3390/min11060625.

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We present the lead isotopic composition of ceramic fragments from the Kyrenia shipwreck (Cyprus), selected from three chemical groups related to the Rhodes and Alimos regions (Greece). Fragments of the lead sheathing covering the ship’s hull and biogenic material formed on some of the ceramic sherds, were analyzed along with sherds from the Rhodes and Alimos source areas for comparison. The objective of this paper was to evaluate the impact of the seawater environment on the isotopic signature of the ceramics, and on our ability to use lead isotopes to source ceramics recovered from seawater.

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Resing, Joseph A., and Francis J. Sansone. "The chemistry of lava-seawater interactions II: the elemental signature." Geochimica et Cosmochimica Acta 66, no. 11 (2002): 1925–41. http://dx.doi.org/10.1016/s0016-7037(01)00897-3.

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Paulukat, Cora, Geoffrey J. Gilleaudeau, Pavel Chernyavskiy, and Robert Frei. "The Cr-isotope signature of surface seawater — A global perspective." Chemical Geology 444 (December 2016): 101–9. http://dx.doi.org/10.1016/j.chemgeo.2016.10.004.

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Ripperger, S., M. Rehkämper, D. Porcelli, and A. N. Halliday. "Cadmium isotope fractionation in seawater — A signature of biological activity." Earth and Planetary Science Letters 261, no. 3-4 (2007): 670–84. http://dx.doi.org/10.1016/j.epsl.2007.07.034.

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Bouchard, Laurianne, Ján Veizer, Laura Kennell-Morrison, Mark Jensen, Ken G. Raven, and Ian D. Clark. "Origin and 87Rb–87Sr age of porewaters in low permeability Ordovician sediments on the eastern flank of the Michigan Basin, Tiverton, Ontario, Canada." Canadian Journal of Earth Sciences 56, no. 3 (2019): 201–8. http://dx.doi.org/10.1139/cjes-2018-0061.

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Porewater extractions and acid leachates of rock core from a 250 m thick sequence of low-permeability Ordovician-age shales and limestones, on the eastern flank of the Michigan Basin, were analysed for strontium isotope ratios in an attempt to infer porewater ages from observed 87Sr/86Sr enrichments. The porewaters originated as Ordovician seawater, which subsequently mixed with evaporated Silurian seawater infiltrating from above, and, to some extent, with a deep brine—with an enriched 87Sr/86Sr signature—from the underlying crystalline shield or deep basin. The porewater 87Sr/86Sr ratios are

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Tignat-Perrier, Romie, Aurélien Dommergue, Alban Thollot, Olivier Magand, Timothy M. Vogel, and Catherine Larose. "Microbial functional signature in the atmospheric boundary layer." Biogeosciences 17, no. 23 (2020): 6081–95. http://dx.doi.org/10.5194/bg-17-6081-2020.

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Abstract. Microorganisms are ubiquitous in the atmosphere, and some airborne microbial cells were shown to be particularly resistant to atmospheric physical and chemical conditions (e.g., ultraviolet – UV – radiation, desiccation and the presence of radicals). In addition to surviving, some cultivable microorganisms of airborne origin were shown to be able to grow on atmospheric chemicals in laboratory experiments. Metagenomic investigations have been used to identify specific signatures of microbial functional potential in different ecosystems. We conducted a comparative metagenomic study on

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Liang, Cheng Hao, Jing Di Yao, Nai Bao Huang, and Jian Hua Wu. "Research on the Shaft-Frequency Electric Field Character of Ship’s Physical Scale Model." Advanced Materials Research 1035 (October 2014): 62–66. http://dx.doi.org/10.4028/www.scientific.net/amr.1035.62.

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By signature gathering system, the shaft-frequency electric field of ship’s physical scale model is measured. At the same time, the mechanism of the corrosion related to shaft-frequency electric field is also described. Results show that the shaft-frequency electric field signature arises around a vessel and transmits in the surrounding seawater due to the current flow from impressed current cathodic protection (ICCP) system and the current flow resulting from the corrosion of dissimilar metals during propeller rotation, which contains both shaft fundamental and harmonics. The signature charac

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11

Mehta, Kurang, Jon L. Sheiman, Roel Snieder, and Rodney Calvert. "Strengthening the virtual-source method for time-lapse monitoring." GEOPHYSICS 73, no. 3 (2008): S73—S80. http://dx.doi.org/10.1190/1.2894468.

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Time-lapse monitoring is a powerful tool for tracking subsurface changes resulting from fluid migration. Conventional time-lapse monitoring can be done by observing differences between two seismic surveys over the surveillance period. Along with the changes in the subsurface, differences in the two seismic surveys are also caused by variations in the near-surface overburden and acquisition discrepancies. The virtual-source method monitors below the time-varying near-surface by redatuming the data down to the subsurface receiver locations. It crosscorrelates the signal that results from surface

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Weiss, Chester J. "The fallacy of the “shallow-water problem” in marine CSEM exploration." GEOPHYSICS 72, no. 6 (2007): A93—A97. http://dx.doi.org/10.1190/1.2786868.

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The recent explosion of activity in offshore controlled-source electromagnetic (CSEM) exploration has shown, both theoretically and in practice for the time-harmonic case, that shallow-water environments (depths less than, say, [Formula: see text]) can pose a significant challenge for detection and characterization of thin resistive targets in the subsurface because the weakly attenuated atmospheric response overprints the weaker target response. As an alternative, the transient CSEM experiment is considered to explore the nature of the “airwave” signature when viewed from the perspective of C

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Hu, Yan, Fang-Zhen Teng, Terry Plank, and Catherine Chauvel. "Potassium isotopic heterogeneity in subducting oceanic plates." Science Advances 6, no. 49 (2020): eabb2472. http://dx.doi.org/10.1126/sciadv.abb2472.

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Oceanic crust and sediments are the primary K sinks for seawater, and they deliver considerable amounts of K to the mantle via subduction. Historically, these crustal components were not studied for K isotopes because of the lack of analytical precision to differentiate terrestrial variations. Here, we report a high-precision dataset that reveals substantial variability in oceanic plates and provides further insights into the oceanic K cycle. Sixty-nine sediments worldwide yield a broad δ41K range from −1.3 to −0.02‰. The unusually low values are indicative of release of heavy K during contine

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Mincer, Tracy J., Paul R. Jensen, Christopher A. Kauffman, and William Fenical. "Widespread and Persistent Populations of a Major New Marine Actinomycete Taxon in Ocean Sediments." Applied and Environmental Microbiology 68, no. 10 (2002): 5005–11. http://dx.doi.org/10.1128/aem.68.10.5005-5011.2002.

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ABSTRACT A major taxon of obligate marine bacteria within the order Actinomycetales has been discovered from ocean sediments. Populations of these bacteria (designated MAR 1) are persistent and widespread, spanning at least three distinct ocean systems. In this study, 212 actinomycete isolates possessing MAR 1 morphologies were examined and all but two displayed an obligate requirement of seawater for growth. Forty-five of these isolates, representing all observed seawater-requiring morphotypes, were partially sequenced and found to share characteristic small-subunit rRNA signature nucleotides

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Narożny, Michał, Paweł Polański, Rafał Namiotko, and Marta Czarnowska. "Relationship Between Basic Physiochemical Properties of Seawater and Magnitude of Underwater Electric Field." Zeszyty Naukowe Akademii Marynarki Wojennej 215, no. 4 (2018): 63–75. http://dx.doi.org/10.2478/sjpna-2018-0027.

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Abstract Passive defense systems which minimize chance of vessel detection have to be utilized due to application of naval mines. Passive defense and signature minimization can be regarded as not only magnitude reduction but also as its shaping. Electric field magnitude at a given depth is a function of an electric field source but also it depends on physicochemical properties of seawater — temperature and salinity. In this paper results of underwater electric field simulations are presented. Cases of various depths, temperatures and salinities are shown. Computational results are compared to

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Emmanuel, Laurent, Maurice Renard, René Cubaynes, et al. "The “Schistes carton” of Quercy (Tarn, France): a lithological signature of a methane hydrate dissociation event in the Early Toarcian. Implications for correlations between Boreal and Tethyan realms." Bulletin de la Société Géologique de France 177, no. 5 (2006): 237–47. http://dx.doi.org/10.2113/gssgfbull.177.5.237.

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Abstract The geochemical events (negative shifts in δ13C and δ18O, and Mn peak) associated with the “Schistes carton” of Quercy (SW France) do not appear to be due only to lithological variations and a differential diagenesis. They correspond to the Lower Toarcian global event and seem to be connected to a destabilization phase of gas hydrates. During its oxidation by seawater, the release of methane gas with a very low carbon isotopic ratio (− 60%) led to the production of CO2 and carbonates with a negative δ13C. The consumption of oxygen in the seawater resulted in conditions that were first

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D’ozouville, Noémi, Sophie Violette, Nathalie Gassama, Aline Dia, and Nathalie Jendrzejewski. "Origin and modelling of water salinization in a coastal aquifer of the Bay of Bengal: The Kaluvelly watershed, Tamil Nadu, India." Bulletin de la Société Géologique de France 177, no. 6 (2006): 333–45. http://dx.doi.org/10.2113/gssgfbull.177.6.333.

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Abstract Over-pumping of the Vanur sandstone aquifer has led to a lowering of the piezometric surface and degradation of water quality through increased salinization. This aquifer salinization is a good example of many similar problems in India and other parts of the world. The Vanur Formation is the main aquifer of a multilayered system bordered by the sea on the eastern side and partly overlaid by the brackish waters of the Kaluvelly swamp in the north. The origin of the salinity, which apparently is not simply seawater intrusion, and its dynamics are examined, using chemical and isotopic to

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Hendry, K. R., G. E. A. Swann, M. J. Leng, et al. "Technical Note: Silica stable isotopes and silicification in a carnivorous sponge <i>Asbestopluma</i> sp." Biogeosciences 12, no. 11 (2015): 3489–98. http://dx.doi.org/10.5194/bg-12-3489-2015.

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Abstract. The stable isotope composition of benthic sponge spicule silica is a potential source of palaeoceanographic information about past deep seawater chemistry. The silicon isotope composition of spicules has been shown to relate to the silicic acid concentration of ambient water, although existing calibrations do exhibit a degree of scatter in the relationship. Less is known about how the oxygen isotope composition of sponge spicule silica relates to environmental conditions during growth. Here, we investigate the vital effects on silica, silicon and oxygen isotope composition in a carni

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Hendry, K. R., G. E. A. Swann, M. J. Leng, et al. "Technical Note: Silica stable isotopes and silicification in a carnivorous sponge \\textit{Asbestopluma} sp." Biogeosciences Discussions 11, no. 12 (2014): 16573–97. http://dx.doi.org/10.5194/bgd-11-16573-2014.

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Abstract. The stable isotope composition of benthic sponge spicule silica is a potential source of palaeoceanographic information about past deep seawater chemistry. The silicon isotopic composition of spicules has been shown to relate to the silicic acid concentration of ambient water, although existing calibrations do exhibit a degree of scatter in the relationship. Less is known about how the oxygen isotope composition of sponge spicule silica relates to environmental conditions during growth. Here, we investigate the biological vital effects on silica silicon and oxygen isotope composition

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Mellon, Craig, Rachel Wood, and Laetitia Pichevin. "Assessing the Reliability of Early Marine Cements in Recording Changes in Seawater Redox Conditions Across the Late-Devonian Mass Extinction." Edinburgh Student Journal of Science 1, no. 1 (2024): 14–18. http://dx.doi.org/10.2218/esjs.9681.

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The Late-Devonian Mass Extinction (LDME) extinguished up to 40% of all marine species, with evidence suggesting marine anoxia was the primary cause. This study performs rare earth element analysis of early marine cements from reefal limestones from Australia and Scotland to show that these cements capture a marine anoxic signature across the LDME for the first time, directly implicating marine anoxia and by extension, the rise of land plants, as the cause of the LDME. This work also demonstrates that early marine cements serve as reliable proxies for recording changes in seawater redox conditi

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Merlivat, Liliane, Jacqueline Boutin, David Antoine, Laurence Beaumont, Melek Golbol, and Vincenzo Vellucci. "Increase of dissolved inorganic carbon and decrease in pH in near-surface waters in the Mediterranean Sea during the past two decades." Biogeosciences 15, no. 18 (2018): 5653–62. http://dx.doi.org/10.5194/bg-15-5653-2018.

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Abstract. Two 3-year time series of hourly measurements of the fugacity of CO2 (fCO2) in the upper 10 m of the surface layer of the northwestern Mediterranean Sea have been recorded by CARIOCA sensors almost two decades apart, in 1995–1997 and 2013–2015. By combining them with the alkalinity derived from measured temperature and salinity, we calculate changes in pH and dissolved inorganic carbon (DIC). DIC increased in surface seawater by ∼25 µmol kg−1 and fCO2 by 40 µatm, whereas seawater pH decreased by ∼0.04 (0.0022 yr−1). The DIC increase is about 15 % larger than expected from the equilib

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Hernández-Morales, Pablo, Jobst Wurl, Carlos Green-Ruiz, and Diego Morata. "Hydrogeochemical Characterization as a Tool to Recognize “Masked Geothermal Waters” in Bahía Concepción, Mexico." Resources 10, no. 3 (2021): 23. http://dx.doi.org/10.3390/resources10030023.

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Geo-thermalism has been widely recognized on the Baja California Peninsula, especially during the last decade. The current research, carried out on Bahia Concepcion, evidences the existence of geothermal springs, which get recharged mainly by groundwater and seawater. The groundwater can be characterized as Na+-Cl− and Na+-HCO3− type, with a pH value close to neutrality. The slightly more acidic thermal sites presented temperatures between 32 °C and 59 °C at the surface. Based on the relationships of the Cl− and Br−, as well as the B/Cl−, and Br−/Cl− ratios, seawater was recognized as the main

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Hao, Ruilin, Liyin Pan, Nana Mu, et al. "Multi-Phase Dolomitization in the Jurassic Paleo-Oil Reservoir Zone, Qiangtang Basin (SW China): Implications for Reservoir Development." Minerals 14, no. 9 (2024): 908. http://dx.doi.org/10.3390/min14090908.

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The age and dolomitization processes in the Paleo-oil reservoir zone, which is composed of massive dolostones found in the Qiangtang Basin (SW China), are still debated. In this research, the Long’eni-Geluguanna Area was selected. Macroscopic information, thin sections, and geochemical methods were used to investigate the dolomitization characteristics and the processes that controlled dolomitization. Five types of replacive dolomites and two types of dolomite cement were observed. Some of the dolomites displayed ghosts of primary sedimentary structures. Saddle dolomites were prevalent, occurr

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D'Andres, Joëlle, Mark A. Kendrick, Vickie C. Bennett, and Allen P. Nutman. "Halogens in serpentinites from the Isua supracrustal belt, Greenland: An Eoarchean seawater signature and biomass proxy?" Geochimica et Cosmochimica Acta 262 (October 2019): 31–59. http://dx.doi.org/10.1016/j.gca.2019.07.017.

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Tortola, Marco, Ihsan S. Al-Aasm, and Richard Crowe. "Diagenetic Pore Fluid Evolution and Dolomitization of the Silurian and Devonian Carbonates, Huron Domain of Southwestern Ontario: Petrographic, Geochemical and Fluid Inclusion Evidence." Minerals 10, no. 2 (2020): 140. http://dx.doi.org/10.3390/min10020140.

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Core samples from two deep boreholes were analyzed for petrographic, stable and Sr isotopes, fluid inclusion microthermometry and major, minor, trace and rare-earth elements (REE) of different types of dolomite in the Silurian and Devonian carbonates of the eastern side of the Michigan Basin provided useful insights into the nature of dolomitization, and the evolution of diagenetic pore fluids in this part of the basin. Petrographic features show that both age groups are characterized by the presence of a pervasive replacive fine-crystalline (<50 µm) dolomite matrix (RD1) and pervasive and

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Barkley, Hannah C., Anne L. Cohen, Yimnang Golbuu, Victoria R. Starczak, Thomas M. DeCarlo, and Kathryn E. F. Shamberger. "Changes in coral reef communities across a natural gradient in seawater pH." Science Advances 1, no. 5 (2015): e1500328. http://dx.doi.org/10.1126/sciadv.1500328.

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Ocean acidification threatens the survival of coral reef ecosystems worldwide. The negative effects of ocean acidification observed in many laboratory experiments have been seen in studies of naturally low-pH reefs, with little evidence to date for adaptation. Recently, we reported initial data suggesting that low-pH coral communities of the Palau Rock Islands appear healthy despite the extreme conditions in which they live. Here, we build on that observation with a comprehensive statistical analysis of benthic communities across Palau’s natural acidification gradient. Our analysis revealed a

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Mazariegos, Junior G., Jennifer C. Walker, Xiaomei Xu, and Claudia I. Czimczik. "Tracing Artificially Recharged Groundwater using Water and Carbon Isotopes." Radiocarbon 59, no. 2 (2016): 407–21. http://dx.doi.org/10.1017/rdc.2016.51.

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AbstractWe conducted an isotopic analysis of groundwater in Orange County, California, USA, around the Talbert Seawater Injection Barrier to determine if recycled water, used to artificially recharge local aquifers, carries a unique isotopic signature that can be used as a tracer. From September 2014 to April 2015, we collected groundwater from six privately owned wells within the coastal groundwater basin, along with various surface waters. All water samples were analyzed for their stable isotopic composition (δ18O, δD), the δ13C and 14C signature of the dissolved inorganic carbon (DIC) pool,

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Moiroud, Mathieu, Emmanuelle Pucéat, Yannick Donnadieu, et al. "Evolution of neodymium isotopic signature of seawater during the Late Cretaceous: Implications for intermediate and deep circulation." Gondwana Research 36 (August 2016): 503–22. http://dx.doi.org/10.1016/j.gr.2015.08.005.

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Samaoui, Samir, Ayoub Aabi, Abdellah Boushaba, et al. "Metallogeny and Genesis of Fault-Filling Barite-Sulfide Veins (Ougnat, Morocco): Petrography, Fluid Inclusion, and Sr-S Isotopic Constraints." Geosciences 14, no. 3 (2024): 83. http://dx.doi.org/10.3390/geosciences14030083.

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The Ougnat Massif of the eastern Anti-Atlas (Morocco) hosts barite and sulfide vein-type deposits of vital economic importance. With over 150 mineralized structures reported in the Ougnat Massif, the ore-bearing ones are predominantly composed of barite, quartz, calcite, and minor portions of sulfides. The mineralized veins are driven by NW-SE and NE-SW to E-W oblique-slip opening faults that cross both the Precambrian basement and its Paleozoic cover. The mineralized structures occur as lenses and sigmoidal veins that follow stepped tension fracture sets oblique to the fault planes. These geo

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Belcher, Anna, Sophie Fielding, Andrew Gray, et al. "Experimental determination of reflectance spectra of Antarctic krill (Euphausia superba) in the Scotia Sea." Antarctic Science 33, no. 4 (2021): 402–14. http://dx.doi.org/10.1017/s0954102021000262.

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AbstractAntarctic krill are the dominant metazoan in the Southern Ocean in terms of biomass; however, their wide and patchy distribution means that estimates of their biomass are still uncertain. Most currently employed methods do not sample the upper surface layers, yet historical records indicate that large surface swarms can change the water colour. Ocean colour satellites are able to measure the surface ocean synoptically and should theoretically provide a means for detecting and measuring surface krill swarms. Before we can assess the feasibility of remote detection, more must be known ab

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Zhang, Qiang, George E. A. Swann, Vanessa Pashley, and Matthew S. A. Horstwood. "Faithful transfer of radiolarian silicon isotope signatures from water column to sediments in the South China Sea." Biogeosciences 22, no. 14 (2025): 3533–46. https://doi.org/10.5194/bg-22-3533-2025.

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Abstract. Radiolarian silicon isotopes (δ30Sirad) hold significant potential as a proxy for constraining past silicon cycling in seawater. However, the extent to which δ30Sirad signatures in sediments accurately represent the isotopic signals of the overlying water column remains unclear, particularly under the influence of radiolarian shell dissolution during sinking and burial in the sediment record. This study presents the first comparative analysis of δ30Sirad compositions and the radiolarian assemblage community using water column and surface sediment samples collected from the South Chin

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Burkholz, Celina, Neus Garcias-Bonet, and Carlos M. Duarte. "Warming enhances carbon dioxide and methane fluxes from Red Sea seagrass (<i>Halophila stipulacea</i>) sediments." Biogeosciences 17, no. 7 (2020): 1717–30. http://dx.doi.org/10.5194/bg-17-1717-2020.

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Abstract. Seagrass meadows are autotrophic ecosystems acting as carbon sinks, but they have also been shown to be sources of carbon dioxide (CO2) and methane (CH4). Seagrasses can be negatively affected by increasing seawater temperatures, but the effects of warming on CO2 and CH4 fluxes in seagrass meadows have not yet been reported. Here, we examine the effect of two disturbances on air–seawater fluxes of CO2 and CH4 in Red Sea Halophila stipulacea communities compared to adjacent unvegetated sediments using cavity ring-down spectroscopy. We first characterized CO2 and CH4 fluxes in vegetate

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Arslan, Niyazi, Meysam Majidi Nezhad, Azim Heydari, Davide Astiaso Garcia, and Georgios Sylaios. "A Principal Component Analysis Methodology of Oil Spill Detection and Monitoring Using Satellite Remote Sensing Sensors." Remote Sensing 15, no. 5 (2023): 1460. http://dx.doi.org/10.3390/rs15051460.

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Monitoring, assessing, and measuring oil spills is essential in protecting the marine environment and in efforts to clean oil spills. One of the most recent oil spills happened near Port Fourchon, Louisiana, caused by Hurricane Ida (Category 4), that had a wind speed of 240 km/h. In this regard, Earth Observation (EO) Satellite Remote Sensing (SRS) images can effectively highlight oil spills in marine areas as a “fast and no-cost” technique. However, clouds and the sea surface spectral signature complicate the interpretation of oil spill areas in the optical images. In this study, Principal Co

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Hall, A. J., A. J. Boyce, and A. E. Fallick. "A Sulphur Isotope Study of Iron Sulphides in the Late Precambrian Dalradian Easdale Slate Formation, Argyll, Scotland." Mineralogical Magazine 52, no. 367 (1988): 483–90. http://dx.doi.org/10.1180/minmag.1988.052.367.06.

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AbstractPyritic slates from the late Precambrian, Middle Dalradian Argyll Group Easdale Slate Formation, contain mainly quartz, muscovite and chlorite with variable amounts of dolomite, albite and paragonite. Slates from Easdale Island and Cuan Ferry contain pyrite porphyroblasts with δ34S = + 12 to + 16‰. The pyrite grew during a post-tectonic retrogressive event at the expense ofpyrrhotine which formed during the main regional metamorphism of the Grampian orogeny by reduction of diagenetic pyrite. Slate from Oban contains abundant diagenetic framboidal pyrite and small syn-tectonic pyrite po

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Ekka, Shail Vijeta, Yu-Hsuan Liang, Kuo-Fang Huang, and Der-Chuen Lee. "Molybdenum Isotopic Fingerprints in Taiwan Rivers: Natural versus Anthropogenic Sources." Water 15, no. 10 (2023): 1873. http://dx.doi.org/10.3390/w15101873.

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Two rivers from Taiwan with different source inputs, the Danshuei (polluted) and Liwu (non-polluted), were selected to study the behavior of molybdenum (Mo) isotopes during weathering and riverine transport. In the Danshuei River, δ98/95Mo ranges from 0.83‰ to 1.50‰ (wet season) and 0.54‰ to 1.25‰ (dry season). With a few exceptions, δ98/95Mo in the Danshuei River is lighter during the wet season, while, in contrast, heavier in the dry season. In the Liwu River, δ98/95Mo varies from 0.54‰ to 1.30‰ and gets heavier along the mainstream. Using the MixSIAR model, three Mo sources are identified i

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Chan, P. T. W., J. Halfar, W. H. Adey, et al. "Recent density decline in wild-collected subarctic crustose coralline algae reveals climate change signature." Geology 48, no. 3 (2019): 226–30. http://dx.doi.org/10.1130/g46804.1.

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Abstract Warming surface ocean temperatures combined with the continued diffusion of atmospheric CO2 into seawater have been shown to have detrimental impacts on calcareous marine organisms in tropical and temperate localities. However, greater oceanic CO2 uptake in higher latitudes may present a higher oceanic acidification risk to carbonate organisms residing in Arctic and subarctic habitats. This is especially true for crustose coralline algae that build their skeletons using high-Mg calcite, which is among the least stable and most soluble of the carbonate minerals. Here we present a centu

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Hofmann, Laurie C., and Svenja Heesch. "Latitudinal trends in stable isotope signatures and carbon-concentrating mechanisms of northeast Atlantic rhodoliths." Biogeosciences 15, no. 20 (2018): 6139–49. http://dx.doi.org/10.5194/bg-15-6139-2018.

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Abstract. Rhodoliths are free-living calcifying red algae that form extensive beds in shallow marine benthic environments (<250 m), which provide important habitats and nurseries for marine organisms and contribute to carbonate sediment accumulation. There is growing concern that these organisms are sensitive to global climate change, yet little is known about their physiology. Considering their broad distribution along most continental coastlines, their potential sensitivity to global change could have important consequences for the productivity and diversity of benthic coastal environment

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Kusakabe, Minoru, Keisuke Nagao, Takeshi Ohba, et al. "Noble gas and stable isotope geochemistry of thermal fluids from Deception Island, Antarctica." Antarctic Science 21, no. 3 (2009): 255–67. http://dx.doi.org/10.1017/s0954102009001783.

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AbstractNew stable isotope and noble gas data obtained from fumarolic and bubbling gases and hot spring waters sampled from Deception Island, Antarctica, were analysed to constrain the geochemical features of the island's active hydrothermal system and magmatism in the Bransfield back-arc basin. The 3He/4He ratios of the gases (< 9.8 × 10-6), which are slightly lower than typical MORB values, suggest that the Deception Island magma was generated in the mantle wedge of a MORB-type source but the signature was influenced by the addition of radiogenic 4He derived from subducted components in t

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Kolo, K., and Ph Claeys. "In vitro formation of Ca-oxalates and the mineral glushinskite by fungal interaction with carbonate substrates and seawater." Biogeosciences 2, no. 3 (2005): 277–93. http://dx.doi.org/10.5194/bg-2-277-2005.

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Abstract. This study investigates the in vitro formation of Ca-oxalates and glushinskite through fungal interaction with carbonate substrates and seawater as a process of biologically induced metal recycling and neo-mineral formation. The study also emphasizes the role of the substrates as metal donors. In the first experiment, thin sections prepared from dolomitic rock samples of Terwagne Formation (Carboniferous, Viséan, northern France) served as substrates. The thin sections placed in Petri dishes were exposed to fungi grown from naturally existing airborne spores. In the second experiment

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Vahrenkamp, Volker C. "Carbon-isotope signatures of Albian to Cenomanian (Cretaceous) shelf carbonates of the Natih Formation, Sultanate of Oman." GeoArabia 18, no. 3 (2013): 65–82. http://dx.doi.org/10.2113/geoarabia180365.

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ABSTRACT The δ13C values of Albian to Cenomanian shallow-marine carbonate sequences of the Natih Formation have been collected from subsurface cores of a key location in Oman. The 450-m-thick stack of shelf carbonates is without significant gaps in deposition. The δ13C data range between 1‰ and 6‰, more-or-less tracking the evolution over time of δ13C in seawater established elsewhere in time-equivalent pelagic carbonate sequences. Anchored by biostratigraphy the isotope profile suggests several additional time correlations. It thus provides significantly enhanced stratigraphic resolution and

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Özyurt, Merve, M. Ziya Kırmacı, Ihsan Al-Aasm, Cathy Hollis, Kemal Taslı, and Raif Kandemir. "REE Characteristics of Lower Cretaceous Limestone Succession in Gümüşhane, NE Turkey: Implications for Ocean Paleoredox Conditions and Diagenetic Alteration." Minerals 10, no. 8 (2020): 683. http://dx.doi.org/10.3390/min10080683.

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Trace and rare earth elements (REEs) are considered to be reliable indicators of chemical processes for the evolution of carbonate systems. One of the best examples of ancient carbonate successions (Berdiga Formation) is widely exposed in NE Turkey. The Lower Cretaceous limestone succession of Berdiga Formation may provide a case study that reveals the effect of ocean paleoredox conditions on diagenetic alteration. Measurement of major, trace and REEs was carried out on the Lower Cretaceous limestones of the Berdiga Formation, to reveal proxies for paleoredox conditions and early diagenetic co

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Harris, Paul (Mitch), Mara R. Diaz, and Gregor P. Eberli. "The Formation and Distribution of Modern Ooids on Great Bahama Bank." Annual Review of Marine Science 11, no. 1 (2019): 491–516. http://dx.doi.org/10.1146/annurev-marine-010318-095251.

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Great Bahama Bank (GBB) is the principal location of the formation and accumulation of ooids (concentrically coated, sand-size carbonate grains) in the world today, and as such has been the focus of studies on all aspects of ooids for more than half a century. Our view from a close look at this vast body of literature coupled with our continuing interests stresses that biological mechanisms (microbially mediated organomineralization) are very important in the formation of ooids, whereas the controlling factor for the distribution and size of ooid sand bodies is the physical energy. Mapping and

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Kellock, Celeste, Maria Cristina Castillo Alvarez, Adrian Finch, et al. "Optimising a method for aragonite precipitation in simulated biogenic calcification media." PLOS ONE 17, no. 12 (2022): e0278627. http://dx.doi.org/10.1371/journal.pone.0278627.

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Resolving how factors such as temperature, pH, biomolecules and mineral growth rate influence the geochemistry and structure of biogenic CaCO3, is essential to the effective development of palaeoproxies. Here we optimise a method to precipitate the CaCO3 polymorph aragonite from seawater, under tightly controlled conditions that simulate the saturation state (Ω) of coral calcification fluids. We then use the method to explore the influence of aspartic acid (one of the most abundant amino acids in coral skeletons) on aragonite structure and morphology. Using ≥200 mg of aragonite seed (surface a

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Blanchet, Cécile L. "A database of marine and terrestrial radiogenic Nd and Sr isotopes for tracing earth-surface processes." Earth System Science Data 11, no. 2 (2019): 741–59. http://dx.doi.org/10.5194/essd-11-741-2019.

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Abstract. The database presented here contains radiogenic neodymium and strontium isotope ratios measured on both terrestrial and marine sediments. The main purpose of this dataset is to help assess sediment provenance and transport processes for various time intervals. This can be achieved by either mapping sediment isotopic signature and/or fingerprinting source areas using statistical tools. The database has been built by incorporating data from the literature and the SedDB database and harmonizing the metadata, especially units and geographical coordinates. The original data were processed

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Faÿ-Gomord, O., C. Allanic, M. Verbiest, et al. "Understanding Fluid Flow during Tectonic Reactivation: An Example from the Flamborough Head Chalk Outcrop (UK)." Geofluids 2018 (2018): 1–17. http://dx.doi.org/10.1155/2018/9352143.

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Flamborough Head chalks are located at the extremities of E-W and N-S trending fault systems along the Yorkshire coast (UK). Rock deformation is expressed in Selwicks Bay where a normal fault is exposed along with a high density of calcite veins. The fault mineralization is tested using geochemistry. Crosscutting relationships are used to differentiate between three vein generations: a network of parallel veins that are oriented perpendicular to stratigraphy (Group I), hydraulic breccia with typical jigsaw puzzle structure (Group II), and a third generation of calcite veins crosscutting the tw

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Vesnaver, Aldo L., Flavio Accaino, Gualtiero Bohm, et al. "Time‐lapse tomography." GEOPHYSICS 68, no. 3 (2003): 815–23. http://dx.doi.org/10.1190/1.1581034.

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In time‐lapse analysis, we have to distinguish the seismic response changes due to oil and gas production at a reservoir over the years from several other causes, such as the recording signature and random noise. In this paper, we focus our attention on the velocity macromodel provided by seismic tomography, which is a basic tool for the data regularization, its depth or time migration, and a possible final subtraction among different vintages. We show first that we cannot use just a single velocity model for all data sets, because of seasonal variations of the overburden velocity (which is ma

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Al-Bassam, Khaldoun S. "STABLE CARBON AND OXYGEN ISOTOPES OF SOME CARBONATE-FLUORAPATITES FROM CENOMANIAN AND TURONIAN SEQUENCES, BOHEMIAN CRETACEOUS BASIN, CZECH REPUBLIC." Iraqi Geological Journal 51, no. 1 (2018): 1–16. http://dx.doi.org/10.46717/igj.51.1.1ms-2018-06-23.

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Stable carbon and oxygen isotopes were analysed in the structural CO3 of carbonate-fluorapatite in phosphate nodules and coprolites present in distinctive horizons at the Cenomanian – Turonian boundary and in late Turonian sequence at the Bohemian Cretaceous Basin of the Czech Republic. The results indicate that the structural CO3 in the analysed carbonate-fluorapatites is depleted in δ13C relative to CO3 in carbonates of comparable age and all samples show negative δ18O values close to those recorded in mid-Cretaceous carbonate-CO3. The obtained δ13C values, however, are higher than those rep

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Potter, Eric G., Colter J. Kelly, William J. Davis, et al. "Fluid sources in basement-hosted unconformity–uranium ore systems: tourmaline chemistry and boron isotopes from the Patterson Lake corridor deposits, Canada." Geochemistry: Exploration, Environment, Analysis 22, no. 1 (2021): geochem2021–037. http://dx.doi.org/10.1144/geochem2021-037.

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The Patterson Lake corridor is a new uranium district located on the southwestern margin of the Athabasca Basin. Known resources extend almost 1 km below the unconformity in graphite- and sulfide-bearing shear zones within highly altered metamorphic rocks. Despite different host rocks and greater depths below the unconformity, alteration assemblages (chlorite, illite, kaolinite, tourmaline and hematite), ore grades and textures are typical of unconformity-related deposits. This alteration includes at least three generations of Mg-rich tourmaline (magnesio-foitite). The boron isotopic compositi

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Brengman, Latisha A., and Christopher M. Fedo. "Development of a mixed seawater-hydrothermal fluid geochemical signature during alteration of volcanic rocks in the Archean (∼2.7 Ga) Abitibi Greenstone Belt, Canada." Geochimica et Cosmochimica Acta 227 (April 2018): 227–45. http://dx.doi.org/10.1016/j.gca.2018.02.019.

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Mackey, DJ. "Copper-complexing capacity of South Pacific waters." Marine and Freshwater Research 37, no. 4 (1986): 437. http://dx.doi.org/10.1071/mf9860437.

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The strong copper-complexing capacity of seawater from the western tropical Pacific Ocean and the Coral Sea has been measured by a method based on competition between naturally occurring ligands and Chelex-100 ion-exchange resin. In the nutrient-depleted surface waters, the values ranged from 4 to 72 nM. For deeper waters there were larger variations with values ranging from 2 to 136 nM in the region of the salinity minimum at approximately 800-1000 m. There was no evidence for increased complexing capacity due to the sediment-water interface. Since changes in complexing capacity are ultimatel

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