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Vanadium isotope evidence for widespread marine oxygenation from the late Ediacaran to early Cambrian

Abstract. 

"Early animals experienced multiple-phase radiations and extinctions from the late Ediacaran to early Cambrian. Oxygen likely played an important role in these evolutionary events, but detailed marine redox evolution during this period remains highly debated. The emerging vanadium (V) isotope system can better capture short-term perturbations to global ocean redox conditions. In this study, we analyzed V isotope compositions [...]".

 

Source: Science Direct 
Authors: Wei Wei et al.
DOI: https://doi.org/10.1016/j.epsl.2022.117942

Read the full article here.


Subpolar gyre decadal variability explains the recent oxygenation in the Irminger Sea

Abstract. 

"Accurate monitoring of the long-term trend of oxygen content at global scale requires a better knowledge of the regional oxygen variability at interannual to decadal time scale. Here, we combined the Argo dataset and repeated ship-based sections to investigate the drivers of the oxygen variability in the North Atlantic Ocean, a key region for the oxygen supply into the deep ocean. We focus on the Labrador Sea Water in the Irminger Sea over the period 1991–2018 and we show that the oxygen solubility explains less than a third of the oxygen variability. [...]".

 

Source: Nature
Authors: Charlène Feucher et al.
DOI: https://doi.org/10.1038/s43247-022-00570-y

Read the full article here.


Authigenic uranium deposition in the glacial North Atlantic: Implications for changes in oxygenation, carbon storage, and deep water-mass geometry

Abstract.

"Oxygen in the ocean has essential ecological and climatic functions, and can be an important indicator of deep-ocean ventilation and carbon storage. Previous studies are divided on whether the subsurface North Atlantic, which today is well-oxygenated, had higher or lower oxygen levels during the Last Glacial Maximum (LGM). Crucially, the limited number of previous reconstructions precludes any conclusions regarding basin-wide patterns in past changes in oxygenation. [...]".

 

Source: Science Direct 
Authors: Yuxin Zhou & Jerry F. McManus
DOI: https://doi.org/10.1016/j.quascirev.2022.107914

Read the full article here.


Geochemical and paleontological evidence of early Cambrian dynamic ocean oxygenation and its implications for organic matter accumulation in mudrocks

Abstract. 

"The evolution of global ocean oxygenation during the early Cambrian remains highly controversial, making it difficult to evaluate how environmental triggers play a role in controlling the organic matter (OM) accumulation in black shales. In this study, an integrated approach, including total organic carbon (TOC) content, major and trace element geochemistry, and microscope images, was systematically conducted in a continuous core well that penetrated through the Lower Cambrian Yanjiahe (YJH)–Shuijingtuo (SJT, subdivided into SM Ⅰ, SM Ⅱ, SM Ⅲ, and SM Ⅳ members) successions (∼541-514Ma) at the Three Gorges area [...]".

 

Source: Science Direct 
Authors: Yu Zhang et al.
DOI: https://doi.org/10.1016/j.marpetgeo.2022.105958

Read the full article here.


Plate tectonics controls ocean oxygen levels

Abstract. 

"Variations in ocean oxygen levels during Earth’s history have been linked to evolution and mass extinctions. Simulations now suggest that the configuration of the continents has a substantial impact on ocean oxygenation. [...]". 

 

Source: Nature
Authors: Katrin J. Meissner & Andreas Oschlies
DOI: https://doi.org/10.1038/d41586-022-02187-9

Read the full article here.


A double-edged sword: The role of sulfate in anoxic marine phosphorus cycling through Earth history

Abstract. 

"Modern anoxic marine sediments release phosphorus (P) to seawater, driving feedbacks at multiple timescales. On sub-Myr timescales, anoxic P regeneration amplifies ocean deoxygenation; on multi-Myr timescales, it stabilizes atmospheric O2. Some authors have extended this thinking to the Precambrian: by analogy, widespread ocean anoxia would imply extensive P regeneration from sediments. However, this neglects the role of sulfate in P regeneration. [...]".

 

Source: Geophysical Research Letters
Authors: Michael A. Kipp
DOI: https://doi.org/10.1029/2022GL099817

Read the full article here.


Ironstone as a proxy of Paleozoic ocean oxygenation

Abstract. 

"Marine ironstone is a Phanerozoic biochemical sedimentary rock that contains abundant primary iron. Although rare, ironstone is conspicuous in the Paleozoic sedimentary record. Its iron source remains contentious, with traditional models invoking a continentally derived source. Increasing sedimentologic evidence suggests that many Paleozoic ironstones formed along favourably oriented continental margins where coastal upwelling delivered ferruginous waters, with the postulated source of iron being deep-ocean hydrothermal fluids. [...]".

 

Source: Science Direct 
Authors: Edward J. Matheson et al.
DOI: https://doi.org/10.1016/j.epsl.2022.117715

Read the full article here.


Continental configuration controls ocean oxygenation during the Phanerozoic

Abstract. 

"The early evolutionary and much of the extinction history of marine animals is thought to be driven by changes in dissolved oxygen concentrations ([O2]) in the ocean. In turn, [O2] is widely assumed to be dominated by the geological history of atmospheric oxygen (pO2). Here, by contrast, we show by means of a series of Earth system model experiments how continental rearrangement during the Phanerozoic Eon drives profound variations in ocean oxygenation and induces a fundamental decoupling in time between upper-ocean and benthic [O2]. [...]". 

 

Source: Nature
Authors: Alexandre Pohl et al.
DOI: https://doi.org/10.1038/s41586-022-05018-z 

Read the full article here.


Mo isotope composition of the 0.85 Ga ocean from coupled carbonate and shale archives: Some implications for pre-Cryogenian oxygenation

Abstract.

"This study addresses marine palaeoredox conditions of the mid-Neoproterozoic by analysing the Mo isotope, trace element, and U-Th-Pb isotope compositions of shallow water microbial carbonate, deep water pelagic carbonate, and shale from the Stone Knife Formation (SKF) in NW Canada. The U-Th-Pb isotope SKF systematics of reef microbialite carbonates, and the moderately expressed negative Ce anomalies are consistent with the presence of dissolved O2 in the surface waters. [...]".

 

Source: Science Direct 
Authors: Edel Mary O'Sullivan et al.
DOI: https://doi.org/10.1016/j.precamres.2022.106760

Read the full article here.


Decoupled oxygenation of the Ediacaran ocean and atmosphere during the rise of early animals

Abstract. 

"The Ediacaran Period (∼635 to 541 Ma) witnessed the early diversification and radiation of metazoans, in the form of the Ediacaran Biota. This biological revolution, beginning at ∼575 Ma, has been widely attributed to a temporally restricted episode of deeper ocean oxygenation, potentially caused by a contemporaneous rise in atmospheric oxygen levels. However, quantitative geochemical-record-driven estimates of Ediacaran atmospheric and oceanic redox evolution are lacking, and hence possible links between oceanic and atmospheric oxygenation remain speculative. [...]". 

 

Source: Science Direct 
Authors: Wei Shi et al.
DOI: https://doi.org/10.1016/j.epsl.2022.117619

Read the full article here.


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