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Marine bioturbation collapse during Early Jurassic deoxygenation: implications for post-extinction marine ecosystem functioning

Abstract. 

"Climate change is undermining the health and integrity of seafloor ecosystems, with declines in bioturbation expected to impact future ecosystem functioning. We explored changes in the nature and degree of bioturbation during Early Jurassic global warming and ocean deoxygenation. Understanding how these communities responded can help anticipate how bioturbation and ecosystem functioning might change over large spatial and temporal scales. Trace and body fossils from outcrop and core in the Cleveland Basin, UK show how healthy seafloor communities deteriorated through the Pliensbachian spinatum Zone, and macroinfaunal behaviour [...]".

 

Source: Geological Society of London
Authors: Bryony A. Caswell & Liam Herringshaw
DOI: https://doi.org/10.1144/SP529-2022-226

Read the full article here.


No evidence for expansion of global ocean euxinia during the base Stairsian mass extinction event (Tremadocian, Early Ordovician)

Abstract.

"A Tremadocian (Early Ordovician, base Stairsian North American Stage) mass extinction event is recorded globally in rocks from several ancient continents and is accompanied by a globally correlated positive carbon isotope excursion (CIE; the largest during the Early Ordovician). In this study, elemental concentrations and uranium isotope compositions (δ238U) were measured for carbonate samples from three sections (along a proximal-to-distal transect: Ibex area, Shingle Pass, Meiklejohn Peak, respectively) in the Great Basin to test the role of ocean anoxia/euxinia on the base Stairsian mass extinction event. [...]".

 

Source: Science Direct 
Authors: Xinze Lu et al. 
DOI: https://doi.org/10.1016/j.gca.2022.11.028

Read the full article here.


GO2NE Webinar on Ocean Deoxygenation

GO2NE Webinar on Ocean Deoxygenation. 

"Do you want to know more about deoxygenation in the ocean?
Join us for the upcoming webinar!

Wednesday, 8 February 2023, 17:00 h – 18:00 CET

Registration link

Please join the Global Ocean Oxygen Network (IOC Expert Working Group GO2NE) for a new session of its webinar series on ocean deoxygenation. The 18th webinar will take place 8 February 2023, 17:00 h CET. This webinar will break from our usual format by featuring presentations from two early-career scientists. Each speaker will have 20 minutes to present their work and a 10 minute moderated discussion session.

Moderation:
Sean Crowe
Departments of Microbiology and Immunology, and Earth, Ocean, and Atmospheric Sciences,
The University of British Columbia, Canada

Speakers:
Kohen Bauer
Ocean Networks Canada,
University of Victoria, British Columbia, Canada
"Ocean anoxia in deep time: Multiple episodes of rapid ocean deoxygenation during the Cretaceous"

Daniel Mills
Department of Earth and Environmental Sciences, Paleontology & Geobiology,
Ludwig-Maximilians-Universität, Munich, Germany
"The control of dissolved O2 on the diversity of microbial eukaryotes over geologic time"

If you are interested to present at one of the upcoming webinars please submit a short abstract here." 


../common/calendar Start Date: 2/8/23

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.


Shallow- and deep-ocean Fe cycling and redox evolution across the Pliensbachian–Toarcian boundary and Toarcian Oceanic Anoxic Event in Panthalassa

Abstract.

"The late Pliensbachian to early Toarcian was characterized by major climatic and environmental changes, encompassing the early Toarcian Oceanic Anoxic Event (T-OAE, or Jenkyns Event, ∼183 Ma) and the preceding Pliensbachian–Toarcian boundary event (Pl/To). Information on seawater redox conditions through this time interval has thus far come mainly from European sections deposited in hydrographically restricted basins, and hence our understanding of the redox evolution of the open ocean (and in particular Panthalassa – the largest ocean to have existed) is limited. [...]".

 

Source: Science Direct 
Authors: Wenhan Chen et al.
DOI: https://doi.org/10.1016/j.epsl.2022.117959

Read the full article here.


Sedimentary molybdenum and uranium: Improving proxies for deoxygenation in coastal depositional environments

Abstract. 

"Sedimentary molybdenum (Mo) and uranium (U) enrichments are widely used to reconstruct changes in bottom water oxygen conditions in aquatic environments. Until now, most studies using Mo and U have focused on restricted suboxic-euxinic basins and continental margin oxygen minimum zones (OMZs), leaving mildly reducing and oxic (but eutrophic) coastal depositional environments vastly understudied. Currently, it is unknown: (1) to what extent Mo and U enrichment factors (Mo- and U-EFs) can accurately reconstruct oxygen conditions in coastal sites experiencing mild deoxygenation, and (2) to what degree secondary [...]". 

 

Source: Science Direct 
Authors: K. Mareike Paul et al.
DOI: https://doi.org/10.1016/j.chemgeo.2022.121203

Read the full article here.


Calcium isotope ratios of malformed foraminifera reveal biocalcification stress preceded Oceanic Anoxic Event 2

Abstract. 

"Ocean acidification causes biocalcification stress. The calcium isotope composition of carbonate producers can archive such stress because calcium isotope fractionation is sensitive to precipitation rate. Here, we synthesize morphometric observations of planktic foraminifera with multi-archive calcium isotope records from Gubbio, Italy and the Western Interior Seaway spanning Cretaceous Ocean Anoxic Event 2 (~94 million years ago). Calcium isotope ratios increase ~60 thousand years prior to the event. [...]". 

 

Source: Nature
Authors: Gabriella D. Kitch et al.
DOI: https://doi.org/10.1038/s43247-022-00641-0

Read the full article here.


Otoliths of marine fishes record evidence of low oxygen, temperature and pH conditions of deep Oxygen Minimum Zones

Abstract.

"The deep-sea is rapidly losing oxygen, with profound implications for marine organisms. Within Eastern Boundary Upwelling Systems, such as the California and the Benguela Current Ecosystems, an important question is how the ongoing expansion, intensification and shoaling of Oxygen Minimum Zones (OMZs) will affect deep-sea fishes throughout their lifetimes. One of the first steps to filling this knowledge gap is through the development of tools and techniques to track fishes’ exposure to hypoxic (<45 μmol kg-1), low-temperature (∼4–10°C) and low-pH (∼7.5) waters when inhabiting OMZs. [...]".

 

Source: Science Direct 
Authors: Leticia Maria Cavole et al.
DOI: https://doi.org/10.1016/j.dsr.2022.103941

Read the full article here.


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