GO₂NE Webinar on Ocean Deoxygenation. 

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

Wednesday, 13th September 2023, 17:00 h – 18:00 CEST

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 22nd webinar will take place 13 September 2023, 17:00 h CEST. 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: 
Lisa Levin
Scripps Institution of Oceanography, UC San Diego, USA

Speakers:
Natalya Gallo
University of Bergen and Bjerknes Centre for Climate Research, Norway
"Trophic impacts of ocean deoxygenation: Disruption of bentho-pelagic coupling in oxygen minimum zone regions"

Anne Gro Vea Salvanes
University of Bergen, Norway
"The bearded goby (Sufflogobius bibarbatus): a hypoxia-tolerant little fish member of the Namibian Benguela Ecosystem"

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

Abstract.

"Oxygen availability is a pivotal factor for ecosystem functioning and the resistance of organisms to the effect of climate change in aquatic habitats. Although extensive work has been done to assess the effect of oxygen on marine and freshwater biota, many studies have not captured the ecological importance of oxygen variations. Overlooking the fluctuating nature of oxygen may cause potential biases in the design and implementation of management policies for aquatic habitats. Conceptual perspectives on the dynamic nature of oxygen fluctuations have been raised in the scientific community in order to enhance [...]".

Source: Biogeosciences
Authors: Marco Fusi et al.
DOI: https://doi.org/10.5194/bg-20-3509-2023

Read the full article here.

Abstract.

"The Cretaceous Oceanic Anoxic Event 2 (OAE2) is a greenhouse episode of severe marine anoxia at the Cenomanian-Turonian boundary. This time interval is characterized by rising sea surface temperature, enhanced marine biological productivity, and widespread occurrence of organic-rich black shales. With an export of biological production to the deep ocean, organisms consume vast amounts of oxygen and subsequently utilize nitrate and sulfate as electron acceptors in organic matter degradation, thereby affecting biogeochemical cycles of nitrogen and sulfur. [...]".

Source: Science Direct
Authors: Ruixiang Zhai et al.
DOI: https://doi.org/10.1016/j.gloplacha.2023.104182

Read the full article here.

Abstract.

"The oceans are losing oxygen (O₂), and oxygen minimum zones are expanding due to climate warming (lower O₂ solubility) and eutrophication related to agriculture. This trend is challenging for most marine taxa that are not well adapted to O₂ depletion. For other taxa this trend might be advantageous because they can withstand low O₂ concentrations or thrive under O₂-depleted or even anoxic conditions. Benthic foraminifera are a group of protists that include taxa with adaptations to partly extreme environmental conditions. [...]".

Source: Biogeosciences
Authors: Nicolaas Glock
DOI: https://doi.org/10.5194/bg-20-3423-2023

Read the full article here.

Abstract.

"Reconstructions of ocean oxygenation are critical for understanding the role of respired carbon storage in regulating atmospheric CO2. Independent sediment redox proxies are essential to assess such reconstructions. Here, we present a long magnetofossil record from the eastern Indian Ocean in which we observe coeval magnetic hardening and enrichment of larger, more elongated, and less oxidized magnetofossils during glacials compared to interglacials over the last ~900 ka. Our multi-proxy records of redox-sensitive magnetofossils, trace element concentrations, and benthic foraminiferal Δδ13C consistently suggest a recurrence of lower O2 [...]".

Source: Nature
Authors: Liao Chang et al.
DOI: https://doi.org/10.1038/s41467-023-40452-1

Read the full article here.

Abstract.

"Oxygen deficient zones (ODZs) account for about 30% of total oceanic fixed nitrogen loss via processes including denitrification, a microbially mediated pathway proceeding stepwise from NO3– to N2. This process may be performed entirely by complete denitrifiers capable of all four enzymatic steps, but many organisms possess only partial denitrification pathways, either producing or consuming key intermediates such as the greenhouse gas N2O. Metagenomics and marker gene surveys have revealed a diversity of denitrification genes within ODZs, but whether these genes co-occur within [...]".

Source: Nature
Authors: Irene H. Zhang et al.
DOI: https://doi.org/10.1038/s43705-023-00284-y

Read the full article here.

Abstract.

"Sinking marine particles drive the biological pump that naturally sequesters carbon from the atmosphere. Despite their small size, the compartmentalized nature of particles promotes intense localized metabolic activity by their bacterial colonizers. Yet the mechanisms promoting the onset of denitrification, a metabolism that arises once oxygen is limiting, remain to be established. Here we show experimentally that slow sinking aggregates composed of marine diatoms—important primary producers for global carbon export—support active denitrification even among bulk oxygenated water typically thought to exclude anaerobic metabolisms. [...]".

Source: Nature
Authors: Davide Ciccarese et al.
DOI: https://doi.org/10.1038/s43247-023-00935-x

Read the full article here.

Abstract.

"Marine anoxia during the Late Triassic has mostly been reported from the western Tethysand Panthalassa, which were near the Central Atlantic Magmatic Province (CAMP), but whether it developed in global open oceans (e.g., the eastern Tethys) is unknown. Whether the marine anoxia was global or regional requires more research. Here, we present carbonate-associated sulfate (CAS) and pyrite δ34Spy data for the Late Triassic–Early Jurassic interval from the Wenquan Section in Qiantang Basin, Tibet. [...]".

Source: Science Direct
Authors: Wei Tang et al.
DOI: https://doi.org/10.1016/j.jseaes.2023.105659

Read the full article here.

Abstract.

"The largest negative inorganic carbon isotope excursion in Earth’s history, namely the Ediacaran Shuram Excursion (SE), closely followed by early animal radiation, has been widely interpreted as a consequence of oceanic oxidation. However, the primary nature of the signature, source of oxidants, and tempo of the event remain contested. Here, we show that carbonate-associated sulfate (CAS) from three different paleocontinents all have conspicuous negative 17O anomalies (Δ′17OCAS values down to −0.53‰) during the SE. [...]".

Source: Nature
Authors: Haiyang Wang et al.
DOI: https://doi.org/10.1038/s41467-023-39962-9

Read the full article here.

Abstract.

"At Site U1516 (Mentelle Basin, southeast Indian Ocean, offshore western Australia), the International Ocean Discovery Program (IODP) Expedition 369 recovered an almost complete pelagic record of the Upper Cretaceous, including the Oceanic Anoxic Event 2 (OAE 2). To better understand paleoenvironmental changes across OAE 2, 32 samples were analysed for benthic foraminiferal abundance data that represent one of the few benthic foraminiferal datasets spanning the OAE 2 in the southern high latitudes. [...]".

Source: Science Direct
Authors: Erik Wolfgring et al.
DOI: https://doi.org/10.1016/j.cretres.2023.105555

Read the full article here.