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Climatic Changes in North Atlantic O2 Amplified by Temperature Sensitivity of Phytoplankton Growth

Abstract.

"Ocean warming is associated with a decline in the global oxygen (O2) inventory, but the ratio of O2 loss to heat gain is poorly understood. We analyzed historical variability in temperature (T), O2, and nitrate (N⁢O3−) in hydrographic observations and model simulations of the North Atlantic, a relatively well-sampled region that is important for deep ocean ventilation. Multidecadal fluctuations of O2 concentrations in subpolar thermocline waters (100–700 m) are correlated with changes in their heat content, with a slope 35% steeper than that expected from thermal solubility. [...]".

 

Source: Wiley Online Library
Authors: Andrew J. Margolskee et al.
DOI: https://doi.org/10.1029/2023GB007930

Read the full article here.


Sedimentary environment and benthic oxygenation history of the Upper Cretaceous Austin Chalk Group, south Texas...

Full title: "Sedimentary environment and benthic oxygenation history of the Upper Cretaceous Austin Chalk Group, south Texas: An integrated ichnological, sedimentological and geochemical approach"

Abstract.

"Oxygen concentration in the ocean is vital for sustaining marine ecosystems. While the potential impacts of deoxygenation on modern oceans are hard to predict, lessons can be learned from better characterizing past geological intervals formed under a greenhouse climate. The greenhouse Cretaceous containing several oceanic anoxic events [...]".

 

Source: Wiley Online Library
Authors: Charlie Y. C. Zheng et al. 
DOI: https://doi.org/10.1111/sed.13169

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!

Monday, 29th January 2024, 10:00 h – 11:00 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 26th webinar will take place 29 January 2024, 10:00 h CET. The webinar will feature presentations by a more senior and an early-career scientist, 20 minutes each followed by 10 minutes moderated discussion sessions. 

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

Moderation
Minhan Dai
Xiamen University, China

Speakers:
Yawei Shen
Xiamen University, China
"Will it be possible to shape the hypoxia tolerance of marine animals? A case study in aquaculture abalone"

Folco Giomi
Independent researcher, Italy
"Marine life on stage. A focus on oxygen availability to the scale of relevant players"

If you want to receive further information about upcoming webinars please register here." 


../common/calendar Start Date: 1/29/24

Hypoxia-tolerant zooplankton may reduce biological carbon pump efficiency in the Humboldt current system off Peru

Abstract.

"In the ocean, downward flux of particles produced in sunlit surface waters is the major component of the biological carbon pump, which sequesters atmospheric carbon dioxide and fuels deep-sea ecosystems. The efficiency of downward carbon transfer is expected to be particularly high in tropical upwelling systems where hypoxia occurring beneath the productive surface waters is thought to hamper particle consumption. However, observations of both particle feeders and carbon export in low-oxygen waters are scarce. Here, we provide evidence that hypoxia-tolerant zooplankton feed on sinking particles in the extensive Oxygen Minimum Zone (OMZ) off Peru. [...]".

 

Source: Nature
Authors: Anja Engel et al. 
DOI: https://doi.org/10.1038/s43247-023-01140-6

Read the full article here.


Fossil-Bearing Concretions of the Araripe Basin Accumulated During Oceanic Anoxic Event 1b

Abstract.

"Fossils from the Araripe Basin (northeastern Brazil) are known for their remarkable preservation of vertebrates and invertebrates, even including soft tissues. They occur in carbonate concretions within organic carbon-rich strata assigned to the Romualdo Formation. Here we present integrated stable isotope, elemental and microfossil records from the Sítio Sobradinho outcrop, Araripe Basin, northeastern Brazil. Our results imply that black shales hosting fossil-bearing carbonate concretions within the lower Romualdo Formation were deposited during Oceanic Anoxic Event (OAE) 1b (Kilian sub-event). [...]".

 

Source: Wiley Online Library
Authors: Marlone H. H. Bom et al.
DOI: https://doi.org/10.1029/2023PA004736

Read the full article here.


Depth Variance of Organic Matter Respiration Stoichiometry in the Subtropical North Atlantic and the Implications for the Global Oxygen Cycle

Abstract.

"Climate warming likely drives ocean deoxygenation, but models still cannot fully explain observed declines in oxygen. One unconstrained parameter is the oxygen demand per carbon respired for complete remineralization of organic matter (i.e., the total respiration quotient, rΣ-O2:C). Here, we tested if rΣ-O2:C declined with depth by quantifying suspended concentrations of particulate organic carbon (POC), particulate organic nitrogen (PON), particulate organic phosphorus (POP), particulate chemical oxygen demand (PCOD), and total oxygen demand (Σ-O2 = PCOD + 2PON) down to a depth of 1,000 m in the Sargasso Sea. [...]".

 

Source: Wiley Online Library
Authors: Skylar D. Gerace et al. 
DOI: https://doi.org/10.1029/2023GB007814

Read the full article here.


Butterfly effect of shallow-ocean deoxygenation on past marine biodiversity

Abstract.

"A geochemical study of an ancient mass-extinction event shows that only moderate expansion of oxygen-deficient waters along continental margins is needed to decimate marine biodiversity. This finding provides a stark warning of the possible consequences of human-driven ocean deoxygenation on life in Earth’s shallow oceans. [...]".

 

Source: Nature
Authors: Brian Kendall
DOI: https://doi.org/10.1038/s41561-023-01310-3

Read the full article here.


Vertical variation of bacterial production and potential role in oxygen loss in the southern Bay of Bengal

Abstract.

"Marine environments wherein long-term microbial oxygen consumption exceeds oxygen replenishment can be associated with oxygen minimum zones (OMZ). The Bay of Bengal OMZ (BOB-OMZ) is one of the most intense OMZs globally. To assess the contribution of bacterial oxygen consumption to oxygen loss in BOB-OMZ, we measured bacterial production (BP), temperature, salinity, and dissolved oxygen (DO) in the whole water column. [...]".

 

Source: Frontiers in Microbiology
Authors: Wenqi Ye et al.
DOI: https://doi.org/10.3389/fmicb.2023.1250575

Read the full article here.


Widespread marine euxinia along the western Yangtze Platform caused by oxygen minimum zone expansion during the Capitanian mass extinction

Abstract.

"The development of widespread marine anoxic and/or euxinic conditions has been proposed as a likely driver of the mid-Capitanian mass extinction. However, the driving mechanisms and spatiotemporal evolution of anoxia/euxinia remain poorly constrained. In order to decipher changes in marine redox conditions and their possible influence on the mid-Capitanian biotic crisis, we applied multiple geochemical indicators to three sections across a shelf-to-basin transect in the Middle Permian Kuhfeng and Lower Yinping formations of the Lower Yangtze Basin, South China. [...]".

 

Source: Science Direct 
Authors: Bolin Zhang et al.
DOI: https://doi.org/10.1016/j.gloplacha.2023.104273

Read the full article here.


Spatial pattern of marine oxygenation set by tectonic and ecological drivers over the Phanerozoic

Abstract.

"Marine redox conditions (that is, oxygen levels) impact a wide array of biogeochemical cycles, but the main controls of marine redox since the start of the Phanerozoic about 538 million years ago are not well established. Here we combine supervised machine learning with shale-hosted trace metal concentrations to reconstruct a near-continuous record of redox conditions in major marine depositional settings. We find synchronously opposite redox changes in upper ocean versus deep shelf and (semi-)restricted basin settings ('redox anticouples', nomen novum) in several multi-million-year intervals, which can be used to track the positions of oxygen-minimum zones and the primary locations of organic burial through time. [...]".

 

Source: Nature
Authors: Xiangli Wang et al. 
DOI: https://doi.org/10.1038/s41561-023-01296-y

Read the full article here.


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