scholarly journals Carbonate-Associated Sulfate in Seep-Bivalve Shells: A New Proxy for Isotope Composition of Seawater Sulfate

2020 ◽  
Author(s):  
Shanggui Gong ◽  
Dong Feng ◽  
Duofu Chen
Keyword(s):  
Isotope Composition ◽  
Carbonate Associated Sulfate ◽  
Seawater Sulfate ◽  
Bivalve Shells

scholarly journals Absolute seasonal temperature estimates from clumped isotopes in bivalve shells suggest warm and variable greenhouse climate

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Niels J. de Winter ◽  
Inigo A. Müller ◽  
Ilja J. Kocken ◽  
Nicolas Thibault ◽  
Clemens V. Ullmann ◽  
...  
Keyword(s):  
Seasonal Variability ◽  
Sea Water ◽  
Isotope Composition ◽  
Sea Surface ◽  
Mean Annual Temperature ◽  
Seasonal Temperature ◽  
Sea Surface Temperatures ◽  
Surface Temperatures ◽  
Temperature Reconstructions ◽  
Bivalve Shells

AbstractSeasonal variability in sea surface temperatures plays a fundamental role in climate dynamics and species distribution. Seasonal bias can also severely compromise the accuracy of mean annual temperature reconstructions. It is therefore essential to better understand seasonal variability in climates of the past. Many reconstructions of climate in deep time neglect this issue and rely on controversial assumptions, such as estimates of sea water oxygen isotope composition. Here we present absolute seasonal temperature reconstructions based on clumped isotope measurements in bivalve shells which, critically, do not rely on these assumptions. We reconstruct highly precise monthly sea surface temperatures at around 50 °N latitude from individual oyster and rudist shells of the Campanian greenhouse period about 78 million years ago, when the seasonal range at 50 °N comprised 15 to 27 °C. In agreement with fully coupled climate model simulations, we find that greenhouse climates outside the tropics were warmer and more seasonal than previously thought. We conclude that seasonal bias and assumptions about seawater composition can distort temperature reconstructions and our understanding of past greenhouse climates.

scholarly journals Using Stable Carbon Isotopes to Quantify Radiocarbon Reservoir Age Offsets in the Coastal Black Sea

Radiocarbon ◽  
2018 ◽  
Vol 61 (1) ◽  
pp. 309-318 ◽  
Author(s):  
Guillaume Soulet ◽  
Liviu Giosan ◽  
Clément Flaux ◽  
Valier Galy
Keyword(s):  
Carbon Isotope ◽  
Black Sea ◽  
Isotope Composition ◽  
Stable Carbon Isotope ◽  
Carbon Isotope Composition ◽  
The Black Sea ◽  
Stable Carbon ◽  
Stable Carbon Isotope Composition ◽  
Reservoir Age ◽  
Bivalve Shells

AbstractConstraining radiocarbon (14C) reservoir age offsets is critical to deriving accurate calendar-age chronologies from 14C dating of materials which did not draw carbon directly from the atmosphere. The application of 14C dating to such materials is severely limited in hydrologically sensitive environments like the Black Sea because of the difficulty to quantify reservoir age offsets, which can vary quickly and significantly through time, due to the dynamics of the biogeochemical cycling of carbon. Here we reconstruct 14C reservoir age offsets (Rshell-atm) of Holocene bivalve shells from the coastal Black Sea relatively to their contemporaneous atmosphere. We show that the 14C reservoir age offset and the stable carbon isotope composition of bivalve shells are linearly correlated in this region. From a biogeochemical standpoint, this suggests that inorganic stable carbon isotope and 14C compositions of Black Sea coastal waters are controlled by the balance between autochthonous primary productivity and heterotrophic respiration of allochthonous pre-aged terrestrial organic matter supplied by rivers. This provided an important implication for Black Sea geochronology as the reservoir age offset of 14C-dated bivalve shell can be inferred from its stable carbon isotope composition. Our results provide a fundamental and inexpensive geochemical tool which will considerably improve the accuracy of Holocene calendar age chronologies in the Black Sea.

scholarly journals Insights into past ocean proxies from micron-scale mapping of sulfur species in carbonates

Geology ◽  
2019 ◽  
Vol 47 (9) ◽  
pp. 833-837 ◽  
Author(s):  
Catherine V. Rose ◽  
Samuel M. Webb ◽  
Matthew Newville ◽  
Antonio Lanzirotti ◽  
Jocelyn A. Richardson ◽  
...  
Keyword(s):  
Atmospheric Oxygen ◽  
Global Ocean ◽  
X Ray ◽  
Carbonate Associated Sulfate ◽  
Mineral Phases ◽  
Seawater Sulfate ◽  
Stable Isotopic ◽  
Marine Carbonates ◽  
The Common ◽  
Anticosti Island

Abstract Geological reconstructions of global ocean chemistry and atmospheric oxygen concentrations over Earth history commonly rely on the abundance and stable isotopic composition (δ34S) of sulfur-bearing compounds. Carbonate-associated sulfate (CAS), sulfate bound within a calcium carbonate mineral matrix, is among the most commonly interrogated sulfur mineral phases. However, recent work has revealed variability in δ34SCAS values that cannot be explained by evolution of the marine sulfate reservoir, challenging the common interpretation that CAS is inherently a high-fidelity record of seawater sulfate. To investigate the source of this inconsistency, we used X-ray spectromicroscopy to map the micron-scale distribution of S-bearing sedimentary phases in Ordovician-aged (ca. 444 Ma) shallow marine carbonates from Anticosti Island, Québec, Canada. Clear differences in the abundance of CAS are observed between cements and fossils, suggesting that variance in bulk-rock data could be a consequence of component mixing and that coupled synchrotron-petrographic screening can identify the carbonate components that are most likely to retain primary CAS. Furthermore, we observe multiple, distinct forms of sulfate (both inorganic and organic). Differences in these forms among fossil clades could provide new insights into biomineralization mechanisms in extinct organisms.

scholarly journals First absolute seasonal temperature estimates for greenhouse climate from clumped isotopes in bivalve shells

2021 ◽  
Author(s):  
Niels de Winter ◽  
Inigo Müller ◽  
Ilja Kocken ◽  
Nicolas Thibault ◽  
Clemens Ullmann ◽  
...  
Keyword(s):  
Seasonal Variability ◽  
Climate Model ◽  
Sea Water ◽  
Isotope Composition ◽  
Seasonal Temperature ◽  
Deep Time ◽  
Temperature Reconstructions ◽  
Climate Model Simulations ◽  
Clumped Isotope ◽  
Bivalve Shells

Abstract Seasonal variability in sea surface temperatures plays a fundamental role in climate dynamics and species distribution. As such, it is essential to better understand seasonal variability in climates of the past. Previous reconstructions of seasonality in deep time are poorly constrained, relying on controversial assumptions such as estimates of seawater composition and neglect seasonal bias. This work presents the first absolute seasonal temperature reconstructions based on clumped isotope measurements in bivalve shells which, critically, do not rely on these assumptions. Our new approach reconstructs highly precise higher mid-latitude (~50°N) monthly temperatures from individual oyster and rudist shells of the Campanian (78 million years ago) greenhouse period (15—27 °C seasonal range). Our analysis demonstrates that seasonal bias and previous assumptions about sea water oxygen isotope composition can lead to highly inaccurate temperature reconstructions, distorting our understanding of the behavior of greenhouse climates and our ability to model them. Our results agree with fully coupled climate model simulations showing greenhouse climates outside the tropics were warmer and more seasonal than previously thought.

scholarly journals First absolute seasonal temperature estimates for greenhouse climate from clumped isotopes in bivalve shells

2020 ◽  
Author(s):  
Niels de Winter ◽  
Inigo Müller ◽  
Ilja Kocken ◽  
Nicolas Thibault ◽  
Clemens Vinzenz Ullmann ◽  
...  
Keyword(s):  
Seasonal Variability ◽  
Climate Model ◽  
Sea Water ◽  
Isotope Composition ◽  
Seasonal Temperature ◽  
Deep Time ◽  
Temperature Reconstructions ◽  
Climate Model Simulations ◽  
Clumped Isotope ◽  
Bivalve Shells

Abstract The seasonal variability of sea surface temperatures plays a fundamental role in climate dynamics and species distribution. As such, it is essential to better understand seasonal variability in warm climates of the past. Previous reconstructions of seasonality in deep time are relatively unconstrained, relying on unsupported assumptions such as estimates of seawater composition and negligible seasonal bias. This work presents the first absolute seasonal temperature reconstructions based on clumped isotope measurements in bivalve shells which, critically, do not rely on these assumptions. Our new approach reconstructs highly precise mid-latitude (~50°N) monthly temperatures from individual oyster and rudist shells of the Campanian (78 million years ago) greenhouse period (15—27 °C seasonal range). Our analysis demonstrates that seasonal bias and previous assumptions about sea water oxygen isotope composition can lead to highly inaccurate temperature reconstructions, distorting our understanding of the behavior of greenhouse climates and our ability to model them. Our results agree remarkably well with fully coupled climate model simulations showing greenhouse climates outside the tropics were warmer with higher seasonality than previously thought.

Dynamic interplay of biogeochemical C, S, and Ba cycles in response to Shuram oxygenation event

2021 ◽  
pp. jgs2021-081
Author(s):  
Huan Cui ◽  
Alan J. Kaufman ◽  
Shuhai Xiao ◽  
Chuanming Zhou ◽  
Maoyan Zhu ◽  
...  
Keyword(s):  
Earth System ◽  
Content Type ◽  
Sulfate Minerals ◽  
Link Type ◽  
Carbonate Associated Sulfate ◽  
Microbial Sulfate Reduction ◽  
The Earth ◽  
Seawater Sulfate ◽  
Supplementary Material ◽  
Dynamic Interplay

Compared with Phanerozoic strata, sulfate minerals are relatively rare in the Precambrian record likely due to the lower concentrations of sulfate in dominantly anoxic oceans. Here, we present a compilation of sulfate minerals that are stratigraphically associated with the Ediacaran Shuram excursion (SE) — the largest negative δ13C excursion in Earth history. We evaluated 15 SE sections, all of which reveal the presence of sulfate minerals and/or concentration enrichment in carbonate-associated sulfate, suggesting a rise in sulfate reservoir. Notably, where data are available, the SE also reveals considerable enrichments in [Ba] relative to pre- and post-SE intervals. We propose that elevated seawater sulfate concentrations during the SE may have faciliated authigenesis of sulfate minerals. At the same time, the rise of Ba concentrations in shelf environments further facilitated barite deposition. A larger sulfate reservoir would stimulate microbial sulfate reduction and anaerobic oxidation of organic matter (including methane), contributing to the genesis of the SE. The existence of sulfate minerals throughout the SE suggests that oxidant pools were not depleted at that time, which challenges previous modelling results. Our study highlights the dynamic interplay of biogeochemical C, S, and Ba cycles in response to the Shuram oxygenation event.Thematic collection: This article is part of the Sulfur in the Earth system collection available at: https://www.lyellcollection.org/cc/sulfur-in-the-earth-systemSupplementary material:https://doi.org/10.6084/m9.figshare.c.5602560

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