黑料视频

Source: Nature
Authors: Helene A. L. Hollitzer et al.
DOI: 10.1038/s41467-024-53557-y

Abstract

"Ocean deoxygenation is becoming a major stressor for marine ecosystems due to anthropogenic climate change. Two major pathways through which climate change affects ocean oxygen are changes in wind fields and changes in air-sea heat and freshwater fluxes. Here, we use a global ocean biogeochemistry model run under historical atmospheric forcing to show that wind stress is the dominant driver of year-to-year oxygen variability in most ocean regions. Only in areas of water mass formation do air-sea heat and freshwater fluxes dominate year-to-year oxygen dynamics. [...]."

Source: Nature
Authors: Bin Zhang et al.
DOI: 10.1038/s43247-024-01897-4

Abstract

"The Neoproterozoic oxygenation event is a milestone in Earth鈥檚 history, yet the redox structure and elemental cycling of the Neoproterozoic ocean remain debated. Here, we investigated iron speciation, molybdenum, and nitrogen isotopes in black shales and manganese carbonates from the upper Ediacaran Doushantuo Formation, South China, to examine the links between redox state, manganese mineralization, and molybdenum cycling. [...]."

Source: Nature 
Authors: Helmke Hepach et al.
DOI: 10.1038/s41598-024-80451-w

Abstract

"Coastal ecosystems are affected by a multitude of anthropogenic stressors. As the Baltic Sea ecosystems rank among the most altered marine ecosystems worldwide, they represent ideal model regions to study ecosystem responses to anthropogenic pressures. Our statistical analysis of data including dissolved organic carbon and nitrogen, as well as bacterial abundance and -biomass production from the time-series station Boknis Eck in the southwestern Baltic Sea reveals that bacterial biomass production intensifies towards summer following the phytoplankton spring bloom. [...]."

"The  webinar series is a regular online seminar series that focuses on the depletion of oxygen in the marine environment 鈥� ocean deoxygenation. Organised and hosted by , each one-hour webinar is run by a guest moderator and two invited speakers. To support the diversity of the scientific community, the webinar series aims for an equal balance of early-career and senior scientists, gender, and geographical representation."

GO2NE Webinar 13 December 2024 No 33

Moderation: 
Shin-ichi Ito
Atmosphere and Ocean Research Institute, The University of Tokyo, Japan

Speakers:
Esther Kennedy
University of Alaska Southeast, USA
"The geography of multivariate climate vulnerability produces mosaic of risks and tradeoffs for California Current shellfish species"

Yusuke Kawaguchi 
Atmosphere and Ocean Research Institute, The University of Tokyo, Japan
"Direct observations of vertical turbulent fluxes of dissolved oxygen using an eddy-covariance system (ECS)"

You can watch the GO₂NE Webinar 13 December 2024 No 33 recording .  

Source: Nature
Authors: Ryohei Yamaguchi et al.
DOI: 10.1038/s43247-024-01886-7

Abstract

"One mechanism by which the ocean uptakes carbon dioxide is through the biological carbon fixation and its subsequent transport to the deep ocean, a process known as the biological carbon pump. Although the importance of the biological pump in the global carbon cycle has long been recognized, its actual contribution remains uncertain. Here, we quantify the carbon export from the upper ocean via the biological carbon pump by revealing the upper ocean dissolved oxygen balance. [...]."

Source: Biogeosciences 
Authors: Keyi Cheng et al.
DOI: 10.5194/bg-21-4927-2024

Abstract

"Iodine (I) abundance in marine carbonates (measured as an elemental ratio with calcium, I鈥�/Ca) is of broad interest as a proxy for local/regional ocean redox. This connection arises because the speciation of iodine in seawater, the balance between iodate (IO3^鈭�) and iodide (I^鈭�), is sensitive to the prevalence of oxic vs. anoxic conditions. However, although I鈥�/Ca ratios are increasingly commonly being measured in ancient carbonate samples, a fully quantitative interpretation of this proxy requires the availability of a mechanistic interpretative framework for the marine iodine cycle that can account for the extent and intensity of ocean deoxygenation in the past. [...]."

Source: Science Direct
Authors: Seerangan Manokaran et al.
DOI: 10.1016/j.rsma.2024.103613

Abstract

"The structural and genetic variation of morphologically adapted polychaetes from the Bay of Bengal continental shelf (North Indian Ocean) including Oxygen Minimum Zone (OMZ) are described. The density and biomass of polychaetes such as Aricidea curviseta (Paronidae), Lumberineris aberrans (Lumberineridae), Prionospio malmgreni, Paraprionospio pinnata, and Prinospio sexoculata (Spionidae) were significantly differed (P<0.05) in depths (Non-Oxygen Minimum Zone - NOMZ and OMZ), transects and cruises. The response and morphometric measures of branchiae structures were inconsistent between OMZ and NOMZ depths. [...]."

Source: Springer Nature  
Authors: Shiro Nishikawa et al.
DOI: 10.1186/s40645-024-00669-0

Abstract

"In this study, we developed a new version of the future ocean regional projection dataset in the North Pacific (FORP-NP10) by performing an ensemble of historical and multi-scenario future projection simulations from 1960 to 2100 using a high-resolution ocean downscaling model system driven by surface forcings based on the atmospheric data of the Coupled Model Intercomparison Project (Phase 5). [...]."

Source: Science Direct
Authors: Shujing Liu et al.
DOI: 10.1016/j.envres.2024.119764

Abstract

"Climate change and eutrophication are accelerating ocean deoxygenation, leading to a global decline in oxygen levels. The East China Sea, frequently experiencing deoxygenation events, harbors diverse microbial communities. However, the response of these communities to the changing deoxygenation dynamics remains poorly understood. Here, we explored the composition and function of microbial communities inhabiting seawaters of the Changjiang Estuary and offshore areas. [...]."

Source: Science Direct
Authors: T.C. Dalseno et al.
DOI: 10.1016/j.rsma.2024.103738

Abstract

"High frequency measurements at the seabed in a shallow semi-enclosed embayment of the Indian Ocean reveal deoxygenation of the bottom water at a rate of 40鈥痬mol O₂ m^鈭�3 d^鈭�1 when seasonal density stratification occurs. The vertical profile of dissolved oxygen below the pycnocline shows concentration decreasing at a constant rate toward the seabed suggesting a benthic sink and an associated downward flux of 鈭�30鈥痬mol O₂ m^鈭�2 d^鈭�1. This is closely coupled to an increase in CO₂ indicative of microbial respiration. [...]."

Source: EGUsphere 
Authors: Michael R. Roman et al.
DOI: 10.5194/bg-21-4975-2024

Abstract

"Anthropogenic warming and nutrient over-enrichment of our oceans have resulted in significant, and often catastrophic, reductions in dissolved oxygen (deoxygenation). Stress on water-breathing animals from this deoxygenation has been shown to occur at all levels of biological organization: cellular, organ, individual, species, population, community, and ecosystem. Most climate forecasts predict increases in ocean deoxygenation; thus, it is essential to develop reliable biological indicators of low-oxygen stress that can be used by regional and global oxygen monitoring efforts to detect and assess the impacts of deoxygenation on ocean life. [...]."

"The  webinar series is a regular online seminar series that focuses on the depletion of oxygen in the marine environment 鈥� ocean deoxygenation. Organised and hosted by , each one-hour webinar is run by a guest moderator and two invited speakers. To support the diversity of the scientific community, the webinar series aims for an equal balance of early-career and senior scientists, gender, and geographical representation."

GO2NE Webinar 25 November 2024 No 32

Moderation: 
Maciej Telszewski
International Ocean Carbon Coordination Project, IOCCP

Speakers:
Linus Stoltz
Commercial Fisheries Research Foundation, USA
"Progress and opportunities using fishing vessels as a platform for widespread coastal DO monitoring"

Michela Martinelli
Institute for Marine Biological Resources and Biotechnology of the National Research Council, Italy
"Progress and opportunities using fishing vessels as a platform for widespread coastal DO monitoring"

You can watch the GO₂NE Webinar 25 November 2024 No 32 recording .  

Source: Science Direct
Authors: Yuzhu Ge et al.
DOI: 10.1016/j.gloplacha.2024.104533

Abstract

"The Toarcian Oceanic Anoxic Event (TOAE; 鈭�183 Ma) represents an important hyperthermal and deoxygenation event in the Early Jurassic. However, TOAE marine records are spatially heterogeneous with regard to nutrient levels, primary productivity, redox conditions and organic enrichment. This non-uniform response to global hyperwarming is not readily accounted for by local variations in paleogeography, climate, or water depth. [...]."

Reoxygenation of marine waters - workshop report 10-11 September 2024

"International experts on ocean oxygen met in-person and online under the auspices of the Intergovernmental Oceanographic Commission of UNESCO (IOC-UNESCO) in Paris, France on September 10-11, 2024, to discuss the theoretical feasibility and possible environmental effects of ideas to reoxygenate ocean regions in order to prevent or reverse ocean deoxygenation.
The workshop was led by the Co-Chairs of the Global Ocean Oxygen Network (GO2NE), an expert working group of IOC-UNESCO formed to advise UNESCO Member States on deoxygenation and raise public awareness of the issue.
Participants will now collaborate on a draft of recommendations to guide the planning and regulation of reoxygenation research and deployment, including pilot studies. Recommendations will be open-access and publicly available."

You can find the workshop report . 

Source: Science Direct
Authors: Amavi N. Silva et al.
DOI: 10.1016/j.jmarsys.2024.103996

Abstract

"Deviations of surface ocean dissolved oxygen (O2) from equilibrium with the atmosphere should be rectified about twenty times more quickly than deviations of dissolved carbon dioxide (CO2). Therefore, persistent O2 disequilibria in the Labrador Sea, while CO2 is close to equilibrium, has been a matter of interest to many previous works. Here we investigate this phenomenon by using a novel analytical technique, the 鈥楥ORS (Carbon Dioxide and Oxygen Relative to Saturation) method鈥�, and also by using more data than was available previously. [...]."

"The  webinar series is a regular online seminar series that focuses on the depletion of oxygen in the marine environment 鈥� ocean deoxygenation. Organised and hosted by , each one-hour webinar is run by a guest moderator and two invited speakers. To support the diversity of the scientific community, the webinar series aims for an equal balance of early-career and senior scientists, gender, and geographical representation."

GO2NE Webinar 31 October 2024 No 31

Moderation: 
Sean Crowe
University of British Columbia, Canada

Speakers:

Earth and Planetary Sciences, ETHZ, Switzerland
"A brief history of oxygen: trace elements as ocean redox proxies"

The Lyell Center, Heriot-Watt University, United Kingdom
"Past ocean oxygen contents of the Pacific"

You can watch the GO₂NE Webinar 31 October 2024 No 31 recording .  

Source: Science Direct
Authors: Yuyang Wu et al.
DOI: 10.1016/j.epsl.2024.118882

Abstract

"Recurrent global marine anoxia marked the Early Triassic in the aftermath of the Permian-Triassic mass extinction. Growing evidence suggests contrasting redox histories across regions, with differing durations and intensities of anoxic conditions, but proposed climate-induced mechanisms for marine anoxia cannot fully explain these contrasting redox histories. Here, we test the impacts of changes in continental configuration on the redox conditions during the Early Triassic. [...]."

Source: Science Direct
Authors: Anna Manyak Davis et al.
DOI: 10.1016/j.ecolmodel.2024.110799

Abstract

"Hypoxia in the world's oceans poses an increasing threat to marine organisms and ecosystems, and there is a need to scale individual effects in order to make predictions about the broader ecological consequences of reduced oxygen availability. Mechanistic models, such as the Dynamic Energy Budget (DEB) model, provide a useful framework for quantifying the effects of changing environmental conditions, such as hypoxia, on individual organismal response. [...]."

Source: Nature
Authors: Kevin C. Rose et al.
DOI: 10.1038/s41559-024-02448-y

Abstract

"Planetary boundaries represent thresholds in major Earth system processes that are sensitive to human activity and control global-scale habitability and stability. These processes are interconnected such that movement of one planetary boundary process can alter the likelihood of crossing other boundaries. Here we argue that the observed deoxygenation of the Earth鈥檚 freshwater and marine ecosystems represents an additional planetary boundary process that is critical to the integrity of Earth鈥檚 ecological and social systems, and both regulates and responds to ongoing changes in other planetary boundary processes. [...]."

Source: Nature
Authors: Kohen W. Bauer et al.
DOI: 10.1038/s41586-024-07876-1

Abstract

"Oceanic anoxic events (OAEs) are historical intervals of global-scale ocean deoxygenation associated with hyperthermal climate states and biological crises. Massive volcanic carbon dioxide (CO2) emissions frequently associated with these events are thought to be a common driver of ocean deoxygenation through several climate-warming-related mechanisms. The Early Cretaceous OAE1a is one of the most intense ocean deoxygenation events, persisting for more than 1鈥塎yr (refs.). [...]."

GOOD News is the newsletter that keeps you up to date on the highlights, events, announcements, and opportunities in the  and the . Compiled by the GO₂NE Secretariat at the , the content of GOOD News is provided by the ocean deoxygenation community. 

In the fifth issue of GOOD News, you can read more about:

• GOOD and GO2NE at the 2024 UN Ocean Decade Conference 
• Updates on GOOD UN Decade Actions 
• Updates on GO2NE papers 
• Call for nominations for new GO2NE Members 
• IOC WESTPAC 2024  
• World Ocean Day
• Publication: The State of the Ocean Report 2024
• Publication: World Ocean Atlas 2023, Volume 3: Dissolved Oxygen, Apparent Oxygen Utilization, Dissolved Oxygen Saturation and 30-year Climate Normal
• Workshop on ecological scenarios and climate storylines in Chilean coastal upwelling systems
• Highlighted upcoming events
• Follow the GO2NE webinar series to learn more about ocean deoxygenation
• Updates on GO2NE members鈥� work
• Relevant events
• Opportunities 

Source: Nature
Authors: Changyu Li et al.
DOI: 10.1038/s41467-024-51323-8

Abstract

"The world鈥檚 oceans are under threat from the prevalence of heatwaves caused by climate change. Despite this, there is a lack of understanding regarding their impact on seawater oxygen levels - a crucial element in sustaining biological survival. Here, we find that heatwaves can trigger low-oxygen extreme events, thereby amplifying the signal of deoxygenation. By utilizing in situ observations and state-of-the-art climate model simulations, we provide a global assessment of the relationship between the two types of extreme events in the surface ocean (0鈥�10鈥塵). [...]."

Source: Science Direct
Authors: Yizhe Gong et al.
DOI: 10.1016/j.palaeo.2024.112281

Abstract

"The role of environmental change as a significant force driving biological evolution during the Ediacaran鈥揅ambrian transition remains a subject of extensive debate. In this study, we present high-resolution C-isotope data of organic matter (未¹³C_org) and multiple S-isotope compositions of pyrite (未³⁴S_py and 螖³³S_py) obtained from a continuous drill core (ZK1505) in South China, spanning the interval from the Ediacaran to Cambrian Stage 2. [...]."

Source: Wiley Online Library
Authors: Jonas Patrik Fredriksson et al.
DOI: 10.1002/lno.12607

Abstract

"The expansion of transient and permanent coastal benthic anoxia is one of the most severe problems for the coastal ocean globally. We report frequent, hidden hypoxia in the bottom 5鈥塩m of the water column of a coastal site in the central Baltic Sea by continuous high-resolution profiling of oxygen (O2) directly above the sediment surface. This hypoxia stood in stark contrast to 30-yr O2 monitoring records at this site that suggest apparent continuous well-oxygenated conditions. [...]."

Source: Science Direct
Authors: Yuhan Zhang et al.
DOI: 10.1016/j.seares.2024.102513

Abstract

"Dissolved oxygen (DO) is one of the core parameters in ocean investigation among various disciplines. The Winkler method, a classical approach, is extensively employed for DO determination. This method uses the reaction of Mn²⁺ to I₃^鈥愨垝 as a proxy to quantitatively convert DO to iodine, followed by titration with sodium thiosulfate solution. However, this method is time-consuming and laborious due to the shaking and/or re-shaking of the DO bottle after adding the pickling reagents and waiting for the precipitate to settle. [...]."

Source: Wiley Online Library
Authors: Ivo da Costa et al.
DOI: 10.1111/2041-210X.14360

Abstract

"1. Global climate-driven ocean warming has decreased dissolved oxygen (DO) levels (ocean deoxygenation) leading to expansions of hypoxic zones, which will affect the movements, behaviour, physiology and distributions of marine animals. However, the precise responses of animals to low DO remains poorly understood because movements and activity levels are seldom recorded alongside instantaneous DO in situ. [...]."

Source: Science Direct
Authors: Mandar Bandekar et al.
DOI: 10.1016/j.marenvres.2024.106615

Abstract

"We examine how oxygen levels and the choice of 16S ribosomal RNA (rRNA) tags impact marine bacterial communities using Next-Generation amplicon sequencing. Analyzing V3 and V6 regions, we assess microbial composition in both Oxygen minimum zones (OMZ) and non-OMZ (NOMZ) areas in the Arabian Sea (AS) and the Central Indian Ocean basin (CIOB) respectively. Operational taxonomic units (OTUs) at 97% similarity showed slightly higher richness and diversity with V6 compared to V3. Vertical diversity patterns were consistent across both regions. [...]."

Source: Frontiers in Marine Science
Authors: Riccardo Gerin et al.
DOI: 10.3389/fmars.2024.1373196

Abstract

"Dissolved oxygen (DO) is one of the most important drivers of ocean biogeochemical cycles and marine life, and in many areas its concentration has declined due to climate change. In recent decades, a growing number of autonomous oceanographic platforms has been equipped with sensors for direct in situ measurements of oxygen levels. However, to ensure high quality and comparable data, these observations need to be validated or, if necessary, corrected. In this paper, we compiled all the available DO data collected by Argo floats and gliders in the South Adriatic Pit (Mediterranean Sea) between 2014 and 2020. [...]."

Source: GeoScienceWorld
Authors: Aihua Yang et al.
DOI: 10.1130/G52200.1

Abstract

"The spread of marine anoxia is believed to have played a key role in the development of the SPICE (Steptoean Positive Carbon Isotope Excursion) event and the end-Marjuman extinction in the late Cambrian (鈭�497.5 m.y. ago), but their cause-and-effect relationship is poorly constrained. Here we present an integrated analysis of carbonate 未13C, cerium anomalies (Ce/Ce*), and genus-level diversity data of trilobites from the North China Platform. [...]."

Source: Wiley Online Library
Authors: Matt J. Waller et al.
DOI: 10.1111/jfb.15830

Abstract

"Levels of dissolved oxygen in open ocean and coastal waters are decreasing (ocean deoxygenation), with poorly understood effects on marine megafauna. All of the more than 1000 species of elasmobranchs (sharks, skates, and rays) are obligate water breathers, with a variety of life-history strategies and oxygen requirements. This review demonstrates that although many elasmobranchs typically avoid hypoxic water, they also appear capable of withstanding mild to moderate hypoxia with changes in activity, ventilatory responses, alterations to circulatory and hematological parameters, and morphological alterations to gill structures. [...]."

Source: Science Direct
Authors: Bo Ping et al.
DOI: 10.1016/j.marenvres.2024.106578

Abstract

"Oceanic dissolved oxygen (DO) is crucial for oceanic material cycles and marine biological activities. However, obtaining subsurface DO values directly from satellite observations is limited due to the restricted observed depth. Therefore, it is essential to develop a connection between surface oceanic parameters and subsurface DO values. Machine learning (ML) methods can effectively grasp the complex relationship between input attributes and target variables, making them a valuable approach for estimating subsurface DO values based on surface oceanic parameters. [...]."

Source: Science Direct
Authors: Paula Diz et al.
DOI: 10.1016/j.pocean.2024.103277

Abstract

"Benthic foraminifera are single-celled organisms inhabiting all marine environments. Despite their high tolerance to oxygen depletion, the prevailing hypothesis anticipates a reduction in their diversity in permanently oxygen-depleted environments, including oxygen minimum zones. Here we re-evaluate diversity and study the endemism of benthic foraminifera in the eastern Pacific, an oceanic area hosting the largest permanently oxygen-depleted waters of the world. [...]."

Source: Science Direct
Authors: Yihua Sun et al.
DOI: 10.1016/j.envres.2024.119011

Abstract

"It is predicted that oxygen minimum zones (OMZs) in the ocean will expand as a consequence of global warming and environmental pollution. This will affect the overall microbial ecology and microbial nitrogen cycle. As one of the world's largest alluvial estuaries, the Yangtze Estuary has exhibited a seasonal OMZ since the 1980s. In this study, we have uncovered the microbial composition, the patterns of community assembly and the potential for microbial nitrogen cycling within the water column of the Yangtze Estuary, with a particular focus on OMZ. [...]."

Source: MDPI
Authors: Caitlin E. Tems & Eric Tappa
DOI: 10.3390/oceans5020021

Abstract

"This study presents a high-resolution record of 未15Nsed, which serves as a proxy for water column denitrification and oxygen minimum zone (OMZ) intensity, from the Soledad Basin in the Eastern Tropical North Pacific OMZ. The Soledad Basin 未15Nsed record is compared to the Pescadero Slope and Santa Barbara Basin (SBB) 未15Nsed records to gain insight into regional variations in the ETNP OMZ. During the Medieval Climate Anomaly (MCA; 950鈥�1250 CE), Soledad Basin, Pescadero Slope, and SBB records exhibit coherent trends suggesting that there was general water column oxygenation stability. [...]."

Source: Frontiers in Marine Science
Authors: Ding Li et al.
DOI: 10.3389/fmars.2024.1380819

Abstract

"Microbial communities within oxygen minimum zones (OMZs) play crucial roles in the marine biogeochemical cycling. Arabian Sea (AS) has one of the largest OMZs among the global oceans, however, knowledge about the microbial ecology of the AS OMZ remained limited. In the present study, 44 water samples collected from six stations across the AS, spanning from the deep chlorophyll maximum (DCM) layer to 4000m depth were analyzed. High-throughput sequencing of 16S rRNA genes revealed the structural diversity of bacterial and archaeal communities, influenced primarily by depth and dissolved oxygen (DO) levels. [...]."

Source: Frontiers in Marine Science
Authors: Jia-Zhen Sun et al.
DOI: 10.3389/fmars.2024.1387552

Abstract

"Respiratory activity in the oceans is declining due to the expansion of hypoxic zones and progressive deoxygenation, posing threats to marine organisms along with impacts of concurrent ocean acidification. Therefore, understanding the combined impacts of reduced pO2 and elevated pCO2 on marine primary producers is of considerable significance. Here, to simulate diatoms鈥� sinking into the aphotic zone of turbid coastal water, we exposed the diatoms Thalassiosira pseudonana and Thalassiosira weissflogii in darkness at 20掳C to different levels of pO2 and pCO2 conditions for ~3 weeks, and monitored their biomass density, photosynthetic activity and dark respiration, and examined their recovery upon subsequent exposure to light at 20掳C, simulating surface water conditions. [...]."

Source: Nature
Authors: Catarina P. P. Martins et al.
DOI: 10.1038/s41598-024-63210-9

Abstract

"Reef-building corals live in highly hydrodynamic environments, where water flow largely controls the complex chemical microenvironments surrounding them鈥攖he concentration boundary layer (CBL). The CBL may be key to alleviate ocean acidification (OA) effects on coral colonies by partially isolating them. However, OA effects on coral CBL remain poorly understood, particularly under different flow velocities. Here, we investigated these effects on the reef-building corals Acropora cytherea, Pocillopora verrucosa, and Porites cylindrica. [...]."

Source: Frontiers in Marine Science
Authors: Maggie D. Johnson et al.
DOI: 10.3389/fmars.2024.1425902

Abstract

"Coastal habitats are under increasing anthropogenic pressures that jeopardize the survival and persistence of ecologically important marine life. One such stressor, increasingly recognized as a significant threat to marine coastal habitats, is deoxygenation (Breitburg et al., 2018; IPCC, 2023). The United Nations Decade of Ocean Science for Sustainable Development has identified deoxygenation as a top international priority for ocean research, with efforts being led by the Global Ocean Oxygen Network (GO2NE) and affiliated programs (Global Ocean Oxygen Decade program). [...]."

Source: Frontiers in Marine Science
Authors: Hongjie Wang et al.
DOI: 10.3389/fmars.2024.1374873

Abstract

"To assess the consequences of nutrient reduction strategies on water quality under climate change, we investigated the long-term dynamics of dissolved oxygen (DO) and pH in Narragansett Bay (NB), a warming urbanized estuary in Rhode Island, where nitrogen loads have declined due to extensive wastewater treatment plant upgrades. We use 15 years (January 2005-December 2019) of measurements from the Narragansett Bay Fixed Site Monitoring network. Nutrient-enhanced phytoplankton growth can increase DO in the upper water column while subsequent respiration can reduce water column DO and enhance bottom water acidification, and vice-versa. [...]."

Source: Nature 
Authors: Ivan Almendra et al.
DOI: 10.1038/s43247-024-01427-2

Abstract

"As a consequence of on-going global warming, the ocean is losing oxygen, which has implications not only in terms of marine resources management and food supply but also in terms of the potentially important feedback on the global carbon cycle and climate. Of particular scrutiny are the extended zones of already low levels of oxygen called the oxygen minimum zones (OMZs) embedded in the subsurface waters of the productive Eastern Boundary Upwelling Systems (EBUS). These OMZs are currently diversely simulated by state-of-the-art Earth System Models (ESM) hampering a reliable projection of ocean deoxygenation on marine ecosystem services in these regions. [...]."

"The  webinar series is a regular online seminar series that focuses on the depletion of oxygen in the marine environment 鈥� ocean deoxygenation. Organised and hosted by , each one-hour webinar is run by a guest moderator and two invited speakers. To support the diversity of the scientific community, the webinar series aims for an equal balance of early-career and senior scientists, gender, and geographical representation."

GO2NE Webinar 11 July 2024 No 30

Moderation: 
Jeremy Sterling
Ocean Science Section, IOC-UNESCO

Speaker:
Simone Moretti
Max Planck Institute for Chemistry, Germany
"The future in the past? Studying past ocean oxygen using nitrogen isotopes and body size of fossil foraminifera" 

You can watch the GO₂NE Webinar 11 July 2024 No 30 recording .  

Source: Science Direct
Authors: Md Mesbah Uddin Bhuiyan et al.
DOI: 10.1016/j.cscee.2024.100621

Abstract

"Oxygen declination in coastal oceans has accelerated drastically in recent decades, both in terms of severity and spatial extent, and such disappearance of oxygen leads to dead zones where life can't survive. This phenomenon is mainly attributed to nutrient pollution and climate change due to intensified anthropogenic activities. The annual statistical oxygen mean concentrations showed the current deoxygenation trends based on (WOA_2001鈥�2018) data comparison of 200 m below the surface water from the first two decades of the 21st century. [...]."

Source: Earth System Science Data
Authors: Nicolas Kolodziejczyk et al.
DOI: 10.5194/essd-16-5191-2024

Abstract

"Recent estimates of the global inventory of dissolved oxygen (DO) have suggested a decrease of 2 % since the 1960s. However, due to the sparse historical oxygen data coverage, the DO inventory exhibits large regional uncertainties over the interannual timescale. Using the In Situ Analysis System for O2 (ISASO2), a new Argo DO-based optimally interpolated climatology at (Kolodziejczyk et al., 2023), we have estimated an updated regional oxygen inventory. Over the long term (鈭� 1980鈥�2013), comparing the ISASO2 Argo fields with the first-guess World Ocean Atlas (WOA18) built from the DO bottle sample fields extracted from the World Ocean Database 2018 (WOD18), the broad tendency to global ocean deoxygenation remains robust in the upper 2000 m, with 鈭�451 卤 243 Tmol per decade. [...]."

"The  webinar series is a regular online seminar series that focuses on the depletion of oxygen in the marine environment 鈥� ocean deoxygenation. Organised and hosted by , each one-hour webinar is run by a guest moderator and two invited speakers. To support the diversity of the scientific community, the webinar series aims for an equal balance of early-career and senior scientists, gender, and geographical representation."

GO2NE Webinar 12 June 2024 No 29 World Oceans Day

"The 29th Global Ocean Oxygen Network (IOC Expert Working Group GO2NE) webinar was a special session of its series on ocean deoxygenation to mark World Oceans Day 2024.
The webinar took place on 12 June 2024, 1500 CEST. It featured presentations by GO2NE Co-Chairs Andreas Oschlies and Caroline Slomp, and expert working group member Karin Limburg, speaking on the latest global scientific efforts to understand, mitigate and adapt to ocean deoxygenation, and the most recent work of GO2NE and its members."

Speakers:
Andreas Oschlies (黑料视频, Germany)
 (Radboud University, The Netherlands)
 (SUNY College of Environmental Science and Forestry, USA)

You can watch the GO₂NE Webinar 12 June 2024 No 29 recording .  

Source: Springer Nature
Authors: Wolfgang Ruebsam & Lorenz Schwark 
DOI: 10.1007/s00531-024-02408-8

Abstract

"The Toarcian Oceanic Anoxic Event (T-OAE, Early Jurassic) is marked by widespread marine deoxygenation and deposition of organic carbon (OC)-rich strata. The genesis of the T-OAE is thought to be associated with environmental changes caused by the emission of 12C-enriched greenhouse gasses (CO2, CH4), manifested in a negative Toarcian carbon isotope excursion (nT-CIE). The nT-CIE is commonly used to stratigraphically define the T-OAE, and despite the complex interrelationship of the different environmental phenomena, both terms (nT-CIE and T-OAE) are commonly used interchangeable. [...]."

Source: Wiley Online Library
Authors: Nicole Buckley et al.
DOI: 10.1029/2023GB007881

Abstract

"Hydrogen sulfide is produced by heterotrophic bacteria in anoxic waters and via carbonyl sulfide hydrolysis and phytoplankton emissions under oxic conditions. Apparent losses of dissolved cadmium (dCd) and zinc (dZn) in oxygen minimum zones (OMZs) of the Atlantic and Pacific Oceans have been attributed to metal-sulfide precipitation formed via dissimilatory sulfate reduction. It has also been argued that such a removal process could be a globally important sink for dCd and dZn. However, our studies from the North Pacific OMZ show that dissolved and particulate sulfide concentrations are insufficient to support the removal of dCd via precipitation. [...]."

Source: Science Direct
Authors: Sung-Uk An et al.
DOI: 10.1016/j.dsr.2024.104295

Abstract

"The potential impact of manganese mining on benthic remineralization in the Pacific Ocean was assessed in this study. We estimated total sediment oxygen uptake rates (TOU) using in situ autonomous benthic chambers at the polymetallic nodule and Co-rich polymetallic crust mining sites of Korea: at the Clarion-Clipperton Fracture Zone (PILOT site) in the eastern Pacific and the open-sea seamounts (OSM) 9-1 and OSM17 in the western Pacific, respectively. [...]."

Source: Nature
Authors: Min Zhang et al.
DOI: 10.1038/s43247-024-01394-8

Abstract

"Expansion of oceanic anoxia is a prevailing hypothesis for driving the marine end-Permian mass extinction and is mainly based on isotopic geochemical proxies. However, long-term oceanic redox conditions before the end-Permian mass extinction remain unresolved. Here we report a secular redox trend based on rock magnetic experiments and cerium anomalies through the Changhsingian and across the Permian-Triassic boundary at the Meishan section, China. Magnetic mineral assemblages changed dramatically at ca. 252.8 million years age (Ma), which indicates that oceanic deoxygenation started about 0.9 million years earlier than the end-Permian mass extinction. [...]."

Source: Frontiers in Marine Science
Authors: Jinyan Liu et al.
DOI: 10.3389/fmars.2024.1396306

Abstract

"Oxygen minimum zones (OMZs) in the ocean are areas with dissolved oxygen (DO) concentrations below critical thresholds that impact marine ecosystems and biogeochemical cycling. In the northern Indian Ocean (NIO), OMZs exhibit a tendency to expand in mesopelagic waters and contribute significantly to global nitrogen loss and climate change. However, the microbial drivers of OMZ expansion in the NIO remain understudied. [...]."

Source: Wiley Online Library
Authors: Friederike Fr枚b et al.
DOI: 10.1029/2023EF004141

Abstract

"The physiological tolerances of marine species toward ambient temperature and oxygen can jointly be evaluated in a single metric: the metabolic index. Changes therein characterize a changing aerobic habitat tailored to species-specific thermal and hypoxia sensitivity traits. If the geographical limits of marine species as indicated by critical thresholds of the metabolic index shift abruptly in response to ocean warming and deoxygenation, aerobic habitat could potentially be lost abruptly. [...]."

Source: Wiley Online Library
Authors: Leissing Frederick et al.
DOI: 10.1002/lno.12556

Abstract

"Ongoing ocean deoxygenation is threatening marine organisms globally. In eastern boundary upwelling systems, planktonic copepods dominate the epipelagic zooplankton, being crucial in the marine food web. Yet, they must cope with severe hypoxia caused by shoaling of the oxygen minimum zone. Based on laboratory experiments during 2021, we found differential responses in the metabolic rate (MR) and critical oxygen partial pressure of three abundant copepods. Calanoides patagoniensis doubled its MR during the upwelling season, so better exploiting the spring phytoplankton bloom for feeding and reproduction while maintaining their critical oxygen partial pressure unchanged between seasons. [...]."

Source: Wiley Online Library
Authors: Patricia Handmann & Douglas Wallace
DOI: 10.1111/gcb.17228

Abstract

"The mitigation of climate change and pollution-related hypoxia and anoxia is a growing challenge for coastal communities. Known ocean conservation measures do not show the desired fast results counteracting deoxygenation. The new infrastructure related to the coastal production of renewable energies linked to the production of green hydrogen can provide new possibilities of artificial ocean reoxygenation to mitigate coastal hypoxia, but has to be treated urgently and seriously from different scientific, engineering and socio-economic angles. [...]."

Source: Wiley Online Library
Authors: Nicole J. Dilernia et al.
DOI: 10.1002/ece3.11100

Abstract

"Oxygen (O2) availability is essential for healthy coral reef functioning, yet how continued loss of dissolved O2 via ocean deoxygenation impacts performance of reef building corals remains unclear. Here, we examine how intra-colony spatial geometry of important Great Barrier Reef (GBR) coral species Acropora may influence variation in hypoxic thresholds for upregulation, to better understand capacity to tolerate future reductions in O2 availability. We first evaluate the application of more streamlined models used to parameterise Hypoxia Response Curve data, models that have been used historically to identify variable oxyregulatory capacity. [...]."

Source: Wiley Online Library
Authors: Esther Portela et al.
DOI: 10.1029/2023JC020259

Abstract

"Quantification of oxygen uptake at the ocean surface and its surface-to-interior pathways is crucial for understanding oxygen concentration change in a warming ocean. We investigate the mean meridional global oxygen transport between 1950 and 2009 using coupled physical-biogeochemical model output. We introduce a streamfunction in latitude-oxygen coordinates to reduce complexity in the description of the mean meridional oxygen pathways. [...]."

"The satellite event 'New approaches to combat eutrophication and hypoxia' brought together partners under the GEF-8 Clean and Healthy Ocean Integrated Program (CHO-IP) for introductions and to begin the next phase of tackling eutrophication and hypoxia in 14 national child projects. Representatives of partner organisations, the Food and Agriculture Organization of the United Nations (FAO), Asian Development Bank (ADB), Development Bank for Latin America (CAF), European Bank for Reconstruction and Development (EBRD), together with the  IOC-UNESCO Global Ocean Oxygen Network (GO₂NE) and the Global Water Partnership (GWP) discussed the program aims and objectives over the course of a 90 minute deoxygenation primer, panel discussion and Q&A session.

Keys points expressed by participants included that:

• Partners across scales and sectors must be involved early, with appropriate financing mechanisms, and engaged throughout to foster project ownership and outcome longevity.
• Scientific data, and methods of access, must be shared openly.
• Science will be unheeded unless it is delivered in a manner that is clear, timely, intelligible, and contextualised and translated to those who have, or will have, the capacity to use it.
• Collaboration with regional actors must be enhanced to aid identification of the most effective science-based actions that will have the highest impact in regional contexts, rather than following global trends.
• International institutions must be encouraged to identify and engage with initiatives of actors in their networks that may already be addressing or adapting to hypoxic conditions.
• Scientifically well-versed personnel are needed in Development Banks and other institutions positioned to leverage existing networks to tackle deoxygenation and other marine issues.

Partners will now move ahead with the program's Global Coordination Project and begin to make connections to national actors and networks working to address eutrophication and hypoxia and implement the program in the 14 participating countries. The program will synergise with the Global Ocean Oxygen Database and Atlas (GO₂DAT), an endorsed action under the UN Ocean Decade of Ocean Science for Sustainable Development and may lead to the development of new Actions as the program is implemented."

Contact: go2ne-secretariat(at)unesco.org

More information:

Source: Wiley Online Library
Authors: Yassir A. Eddebbar et al.
DOI: 10.1029/2023JC020588

Abstract

"In the tropical Pacific, weak ventilation and intense microbial respiration at depth give rise to a low dissolved oxygen (O2) environment that is thought to be ventilated primarily by the equatorial current system (ECS). The role of mesoscale eddies and vertical mixing as potential pathways of O2 supply in this region, however, remains poorly known due to sparse observations and coarse model resolution. Using an eddy resolving simulation of ocean circulation and biogeochemistry, we assess the contribution of these processes to the O2 budget balance and find that vertical mixing of O2, which is modulated by the surface wind speed and the vertical shear of the eddying currents, contributes substantially to the replenishment of O2 in the upper equatorial Pacific thermocline, complementing the advective supply of O2 by the ECS and meridional circulation at depth. [...]."

Source: Science Direct
Authors: Vidhya Vijayasenan et al.
DOI: 10.1016/j.marenvres.2024.106380

Abstract

"The largest continental shelf Oxygen Minimum Zone (OMZ) in the world is formed along the Indian western shelf in the eastern Arabian Sea during the Southwest Monsoon [(SWM); June鈥揝eptember], which is a natural pollution event associated with the coastal upwelling. This study examines the composition, abundance, and distribution of copepods during the Northeast Monsoon [(NEM); November to February] and SWM in 50 m depth zones along the Indian western shelf in the eastern Arabian Sea. [...]."

Source: Science Direct
Authors: Bokun Chen et al.
DOI: 10.1016/j.envexpbot.2024.105667

Abstract

"Hypoxic zones and oceanic deoxygenation are spreading worldwide due to anthropogenic activities and climate change, greatly affecting marine organisms exposed to lowered O2. Yet, the effects of the lowered O2 on phytoplankton are often neglected when studying O2 effects as they are the O2 producers. Here we showed that low O2 (dissolved O2, 150 卤 10 渭mol L鈭�1) enhanced the growth of the marine diatom Thalassiosira pseudonana in limited light but reduced it in moderate to inhibitory light and that hypoxia (40 卤 7.5 渭mol L鈭�1) reduced its growth at any growth lights. [...]."

Source: Science Direct
Authors: Corianna Flannery & Eric P. Bjorkstedt
DOI: 10.1016/j.jembe.2024.151993

Abstract

"Reef fishes in the California Current Ecosystem have evolved in habitats affected by seasonally variable, episodic upwelling of high pCO2 (acidified, low pH) and low dissolved oxygen (deoxygenated) water, which suggests that these fishes might exhibit resilience to ocean acidification (OA) and deoxygenation. Yet, how the fitness of these fish are affected by natural variability in pH and DO over short time scales remains poorly understood, as do the effects of longer-term trends in pH and DO driven by climate change. [...]."

Source: Science Direct
Authors: Akira Iguchi et al.
DOI: 10.1016/j.scitotenv.2023.169484

Abstract

"Ocean acidification and deoxygenation co-occur in marine environments, causing deterioration of marine ecosystems. However, effects of compound stresses on marine organisms and their physiological coping mechanisms are largely unknown. Here, we show how high pCO2 and low dissolved oxygen (DO) cause transcriptomic changes in eggs of a demersal fish (Sillago japonica), which are fully exposed to such stresses in natural environment. Overall gene expression was affected more strongly by low DO than by high pCO2. Enrichment analysis detected significant stress responses such as glycolytic processes in response to low DO. [...]."

Source: Biogeosciences
Authors: David J. Yousavich et al.
DOI: 10.5194/bg-21-789-2024

Abstract

"The Santa Barbara Basin naturally experiences transient deoxygenation due to its unique geological setting in the southern California Borderland and seasonal changes in ocean currents. Long-term measurements of the basin showed that anoxic events and subsequent nitrate exhaustion in the bottom waters have been occurring more frequently and lasting longer over the past decade. One characteristic of the Santa Barbara Basin is the seasonal development of extensive mats of benthic nitrate-reducing sulfur-oxidizing bacteria, which are found at the sediment鈥搘ater interface when the basin's bottom waters reach anoxia but still provide some nitrate. To assess the mat's impact on the benthic and pelagic redox environment, we collected biogeochemical sediment and benthic flux data in November 2019, after anoxia developed in the deepest waters of the basin and dissolved nitrate was depleted (down to 9.9 碌M). [...]."

"The  webinar series is a regular online seminar series that focuses on the depletion of oxygen in the marine environment 鈥� ocean deoxygenation. Organised and hosted by , each one-hour webinar is run by a guest moderator and two invited speakers. To support the diversity of the scientific community, the webinar series aims for an equal balance of early-career and senior scientists, gender, and geographical representation."

GO2NE Webinar 03 April 2024 No 28

Moderation: 
Aileen Tan Shau Hwai
Centre For Marine & Coastal Studies, Unversiti Sains Malaysia, Malaysia

Speakers:

Centre for Environment Fisheries and Aquaculture Science (CEFAS), United Kingdom
"Observing ocean oxygen in UK shelf seas"

Marine Science Program, Faculty of Science and Marine Environment, Universiti Malaysia Terengganu, Malaysia
"High biomass diatom blooms induced the formation of hypoxic-anoxic zones in the inner part of Johor Strait"

You can watch the GO₂NE Webinar 03 April 2024 No 28 recording .  

Source: Science Direct
Authors: Xuguang Feng et al.
DOI: 10.1016/j.palaeo.2023.111982

Abstract

"Accelerated Arctic warming has raised concerns about future environmental conditions in the Bering Sea, one of the world's most productive marine ecosystems. Marine Isotope Stage (MIS) 11 (424鈥�374 ka), a period with orbital parameters similar to those of the current interglacial (Holocene), is thought to be a suitable analog to predict future marine environments. Here, we reconstruct paleoredox changes in the Bering Sea over the last 800 kyr using high-resolution U/Th ratios from four sites, which were sampled by the Integrated Ocean Drilling Program (IODP) Expedition 323. [...]."

Source: Annual Reviews 
Authors: Curtis Deutsch et al.
DOI: 10.1146/annurev-marine-040323-095231

Abstract

"The ocean enabled the diversification of life on Earth by adding O2 to the atmosphere, yet marine species remain most subject to O2 limitation. Human industrialization is intensifying the aerobic challenges to marine ecosystems by depleting the ocean's O2 inventory through the global addition of heat and local addition of nutrients. Historical observations reveal an 鈭�2% decline in upper-ocean O2 and accelerating reports of coastal mass mortality events. The dynamic balance of O2 supply and demand provides a unifying framework for understanding these phenomena across scales from the global ocean to individual organisms. [...]."

Source: Science 
Authors: Yi Wang et al.
DOI: 10.1126/sciadv.adk2506

Abstract

"Ocean dissolved oxygen (DO) can provide insights on how the marine carbon cycle affects global climate change. However, the net global DO change and the controlling mechanisms remain uncertain through the last deglaciation. Here, we present a globally integrated DO reconstruction using thallium isotopes, corroborating lower global DO during the Last Glacial Maximum [19 to 23 thousand years before the present (ka B.P.)] relative to the Holocene. [...]."

Source: Springer Nature 
Authors: Nicolas E. Humphries et al.
DOI: 10.1007/s00227-023-04366-2

Abstract

"Oxygen minimum zones in the open ocean are predicted to significantly increase in volume over the coming decades as a result of anthropogenic climatic warming. The resulting reduction in dissolved oxygen (DO) in the pelagic realm is likely to have detrimental impacts on water-breathing organisms, particularly those with higher metabolic rates, such as billfish, tunas, and sharks. However, little is known about how free-living fish respond to low DO environments, and therefore, the effect increasing OMZs will have cannot be predicted reliably. Here, we compare the responses of two active predators (bigeye tuna Thunnus obesus and yellowfin tuna Thunnus albacares) to DO at depth throughout the eastern Pacific Ocean. Using time-series data from 267 tagged tunas (59,910 days) and 3D maps of modelled DO, we find that yellowfin tuna respond to low DO at depth by spending more time in shallower, more oxygenated waters. [...]."

Source: Frontiers in Marine Science
Authors: Sara D. Swaminathan et al.
DOI: 10.3389/fmars.2023.1301474

Abstract

"Ocean deoxygenation is intensifying globally due to human activities 鈥� and is emerging as a grave threat to coral reef ecosystems where it can cause coral bleaching and mass mortality. However, deoxygenation is one of many threats to coral reefs, making it essential to understand how prior environmental stress may influence responses to deoxygenation. To address this question, we examined responses of the coral holobiont (i.e., the coral host, Symbiodiniaceae, and the microbiome) to deoxygenation in corals with different environmental stress backgrounds. [...]."

Source: Science Direct
Authors: Ricardo D. Monedero-Contreras et al.
DOI: 10.1016/j.palaeo.2023.111953

Abstract

"Global warming and anthropogenic activity are boosting marine deoxygenation in many regions around the globe. Deoxygenation is a critical ocean stressor with profound implications for marine ecosystems and biogeochemical cycles. Understanding the dynamics and evolution of past deoxygenation events can enhance our knowledge of present-day and future impacts of climate change and anthropogenic pressure on marine environments. Many studies have reconstructed the evolution redox conditions of past deoxygenation events using geochemical proxies. [...]."

Source: Science Direct
Authors: Alan Maria Mancini et al.
DOI: 10.1016/j.earscirev.2023.104664

Abstract

"Despite the observation that we are witnessing a true oxygen crisis, the ocean deoxygenation theme is getting less attention from the media and population compared to other environmental stressors concerning climate change. The current ocean oxygen crisis is characterized by a complex interplay of climatic, biological, and oceanographic processes acting at different time scales. Earth system models offer insights into future deoxygenation events and their potential extent; however, their capacity to precisely constrain these events is complicated by the intricate interplay of various interconnected feedback mechanisms. [...]."

Source: Science Direct 
Authors: Gabriele Gambacorta et al.
DOI: 10.1016/j.earscirev.2023.104636

Abstract

"The early Toarcian Oceanic Anoxic Event (Jenkyns Event) was associated with major world-wide climatic changes with profound effects on the global carbon cycle. This review revisits the available literature covering the Jenkyns Event applying an updated common stratigraphic definition, allowing illustration of the development and evolution of anoxia in the Alpine-Mediterranean Tethys, north African margin, and North European epicontinental basins within a high-resolution temporal framework. [...]."

Source: Science Direct 
Authors: Makiko Yorifuji et al.
DOI: 10.1016/j.marpolbul.2023.115896

Abstract

"Acidification and deoxygenation are major threats to ocean environments. Despite the possibilities of their co-occurrence, little is known about their interactive effects on marine organisms. The effects of low pH and low dissolved oxygen (DO) on the early life stages of the coastal fish Sillago japonica were investigated. Twenty-five experimental treatments fully crossed in five levels of pH 7.6鈥�8.1 and DO 50鈥�230 渭mol/kg (20鈥�100 % saturation degree) were tested, and hatching rate of the embryos and survivability of the larvae after 24 h at 25 掳C were investigated. [...]."

Source: MDPI
Authors: Zhenguo Wang et al.
DOI: 10.3390/rs16020228

Abstract

"Dissolved oxygen (DO) is essential for assessing and monitoring the health of marine ecosystems. The phenomenon of ocean deoxygenation is widely recognized. Nevertheless, the limited availability of observations poses a challenge in achieving a comprehensive understanding of global ocean DO dynamics and trends. The study addresses the challenge of unevenly distributed Argo DO data by developing time鈥搒pace鈥揹epth machine learning (TSD-ML), a novel machine learning-based model designed to enhance reconstruction accuracy in data-sparse regions. [...]."

Source: Frontiers in Marine Science
Authors: Rushingisha George et al. 
DOI: 10.3389/fmars.2023.1286870

Abstract

"Ocean acidification, deoxygenation, and warming are three interconnected global change challenges caused by increased anthropogenic carbon emissions. These issues present substantial threats to marine organisms, ecosystems, and the survival of coastal communities depending on these ecosystems. Coastal upwelling areas may experience significant declines in pH, dissolved oxygen (DO), and temperature levels during upwelling events, making marine organisms and ecosystems in these areas more susceptible to ocean acidification and deoxygenation. Understanding the dynamics of pH, DO, and temperature in coastal upwelling areas is essential for evaluating the susceptibility of resident organisms and ecosystems to lower pH and DO conditions occurring during upwelling events. [...]."

Source: Frontiers in Marine Science
Authors: Masahito Shigemitsu et al.
DOI: 10.3389/fmars.2023.1355015

Abstract

"Ocean deoxygenation is a key stressor for marine ecosystems and biogeochemical cycles (Gruber, 2011; Breitburg et al., 2018). Climate projections based on Earth system models (ESMs) suggest that the global oxygen inventory will undergo a significant decline over the next century under persistent greenhouse gas emissions (Bopp et al., 2013; Kwiatkowski et al., 2020). Oxygen minimum zones (OMZs) located close to productive eastern boundary upwelling systems (EBUSs) and the Arabian Sea may expand or shift in spatial extent dramatically, thereby impacting regional marine habitats (Stramma et al., 2012) and ecosystem services (Lachkar et al., 2023). [...]."

Source: Science Direct 
Authors: Alan Maria Mancini et al.
DOI: 10.1016/j.dsr.2023.104217

Abstract

"During the Messinian, the sensitivity of the Mediterranean Basin to ecosystem perturbation was enhanced in response to the progressive restriction of water exchange with the Atlantic Ocean. The widespread deposition of organic-rich layers (i.e. sapropel) during the Messinian testifies the perturbation of the carbon and oxygen cycles; indeed, these sediments were deposited under conditions of oxygen starvation, presumably in response to a periodic deterioration of the thermohaline circulation strength. [...]."

Source: Biogeosciences
Authors: Sabine Mecking & Kyla Drushka
DOI: 10.5194/bg-21-1117-2024

Abstract

"Understanding the response of the ocean to global warming, including the renewal of ocean waters from the surface (ventilation), is important for future climate predictions. Oxygen distributions in the ocean thermocline have proven an effective way to infer changes in ventilation because physical processes (ventilation and circulation) that supply oxygen are thought to be primarily responsible for changes in interior oxygen concentrations. Here, the focus is on the North Pacific thermocline, where some of the world's oceans' largest oxygen variations have been observed. [...]."

"The  webinar series is a regular online seminar series that focuses on the depletion of oxygen in the marine environment 鈥� ocean deoxygenation. Organised and hosted by , each one-hour webinar is run by a guest moderator and two invited speakers. To support the diversity of the scientific community, the webinar series aims for an equal balance of early-career and senior scientists, gender, and geographical representation."

GO2NE Webinar 21 February 2024 No 27

Moderation: 

University of Bergen and Bjerknes Centre for Climate Research, Norway

Speakers:

University of Bergen and Bjerknes Centre for Climate Research, Norway
"Vertical distribution of mesopelagic scattering layers under different oxygen conditions: Insights from a western Norwegian fjord"

GeoZentrum Nordbayern, Germany - Paleobiology, and Integrative Ecophysiology at AWI, Germany
"Warming-associated deoxygenation as a driver of marine extinction? The deep past and near future"

You can watch the GO₂NE Webinar 21 February 2024 No 27 recording .  

Source: Biogeosciences
Authors: Simone R. Alin et al.
DOI: 10.5194/bg-21-1639-2024

Abstract

"Coastal and estuarine ecosystems fringing the North Pacific Ocean are particularly vulnerable to ocean acidification, hypoxia, and intense marine heatwaves as a result of interactions among natural and anthropogenic processes. Here, we characterize variability during a seasonally resolved cruise time series (2014鈥�2018) in the southern Salish Sea (Puget Sound, Strait of Juan de Fuca) and nearby coastal waters for select physical (temperature, T; salinity, S) and biogeochemical (oxygen, O₂; carbon dioxide fugacity, fCO₂; aragonite saturation state, 惟_arag) parameters. [...]."

Source: Biogeosciences
Authors: Sabine Schmidt & Ibrahima Iris Diallo
DOI: 10.5194/bg-21-1785-2024

Abstract

"The French coast facing the Bay of Biscay (North-East Atlantic) is characterised by the presence of small macrotidal and turbid estuaries, including the Charente, which is geographically located between the two large estuaries of the Gironde and the Loire (south-west France). Multi-year, multi-site and high-frequency water quality surveys have shown that the Loire and, to a lesser extent, the Gironde suffer from summer hypoxia. These observations raised the question of the possible occurrence of hypoxia, particularly in one of these small estuaries, the Charente, which flows into the Bay of Marennes-Ol茅ron, the first oyster-farming area in France. [...]."

GOOD News is the newsletter that keeps you up to date on the highlights, events, announcements, and opportunities in the  and the . Compiled by the GO₂NE Secretariat at the , the content of GOOD News is provided by the ocean deoxygenation community. 

In the fourth issue of GOOD News, you can read more about:

• GO2NE virtual workshops
• GO2NE communication survey results 
• GOOD-OARS-CLAP-COPAS Summer School 2023
• GO2NE at UNFCCC COP 28
• Deoxygenation Sessions at the 2nd UN Ocean Decade Regional Conference & 11th WESTPAC International Marine Science Conference 
• World Ocean Day, 8 June 2024
• GO2NE webinar series
• Updates on GO2NE members鈥� work
• Events, announcements, and opportunities 

Source: Biogeosciences
Authors: Lyuba Novi et al.
DOI: 10.5194/bg-21-3985-2024

Abstract

"This study examines the linkages between the upper-ocean (0鈥�200鈥塵) oxygen (O2) content and stratification in the North Pacific Ocean using four Earth system models (ESMs), an ocean hindcast simulation, and an ocean reanalysis. The trends and variability in oceanic O2 content are driven by the imbalance between physical supply and biological demand. Physical supply is primarily controlled by ocean ventilation, which is responsible for the transport of O2-rich surface waters to the subsurface. Isopycnic potential vorticity (IPV), a quasi-conservative tracer proportional to density stratification that can be evaluated from temperature and salinity measurements, is used herein as a dynamical proxy for ocean ventilation. [...]."

"The  webinar series is a regular online seminar series that focuses on the depletion of oxygen in the marine environment 鈥� ocean deoxygenation. Organised and hosted by , each one-hour webinar is run by a guest moderator and two invited speakers. To support the diversity of the scientific community, the webinar series aims for an equal balance of early-career and senior scientists, gender, and geographical representation."

GO2NE Webinar 29 January 2024 No 26

Moderation: 

Xiamen University, China

Speakers:

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

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

You can watch the GO₂NE Webinar 29 January 2024 No 26 recording .  

Source: Science Direct
Authors: Lander Merma-Mora et al.
DOI: 10.1016/j.jmarsys.2023.103918

Abstract

"Coastal hypoxia can occur naturally in inshore areas of the Eastern Boundary Upwelling Systems, influenced by the nutrient-rich and low-oxygen upwelling waters. This study aims to explore the influence of water stratification and winds on bottom-water hypoxia of the Paracas Bay, an area subjected to the most intense alongshore winds and active coastal upwelling in the Peruvian coast. Monitoring data of the Pisco-Paracas water properties (dissolved oxygen, temperature, salinity and estimated stratification), the Pisco River flow, and the intensities of surface winds of the outside upwelling area, and of the local area, were analysed for the period 2006 to 2015. [...]."