News

Ocean Oxygen: the role of the Ocean in the oxygen we breathe and the threat of deoxygenation

Abstract.

"EMB Future Science Brief No. 10 highlights the most recent science on Ocean oxygen, including causes, impacts and mitigation strategies of Ocean oxygen loss, and discusses whether “every second breath we take comes from the Ocean”. It closes with key policy, management and research recommendations to address Ocean deoxygenation and communicate more accurately about the role of the Ocean in Earth’s oxygen. 
The sentence “every second breath you take comes from the Ocean” is commonly used in Ocean Literacy and science communication to highlight the importance of Ocean oxygen. [...]".

 

Source: European Marine Board
Authors: Marilaure Grégoire et al.
DOI: 10.5281/zenodo.7941157

Read the full article here.


A well-oxygenated eastern tropical Pacific during the warm Miocene

Abstract.

"The oxygen content of the oceans is susceptible to climate change and has declined in recent decades, with the largest effect in oxygen-deficient zones (ODZs), that is, mid-depth ocean regions with oxygen concentrations <5 μmol kg−1 (ref.). Earth-system-model simulations of climate warming predict that ODZs will expand until at least 2100. The response on timescales of hundreds to thousands of years, however, remains uncertain. Here we investigate changes in the response of ocean oxygenation during the warmer-than-present Miocene Climatic Optimum (MCO; 17.0–14.8 million years ago (Ma)). [...]".

 

Source: Nature
Authors: Anya V. Hess et al.
DOI: https://doi.org/10.1038/s41586-023-06104-6

Read the full article here.


A Selected Review of Impacts of Ocean Deoxygenation on Fish and Fisheries

Abstract.

"Oxygen is crucial for the survival of marine species. Yet, the ocean has experienced a loss of approximately 2% of its oxygen inventory since the last century, resulting in adverse impacts on marine life and ecosystems. In particular, changes in the gap between the supply and demand for dissolved oxygen lead to physiological and ecological variations, which cause alterations in habitats and food webs for fish and ecosystem services. These changes vary over time and by region, and the heterogeneous characteristics of marine species bring about non-linear consequences to human society. [...]".

 

Source: MDPI
Authors: Hongsik Kim et al.
DOI: https://doi.org/10.3390/fishes8060316

Read the full article here. 


Impact of deoxygenation and warming on global marine species in the 21st century

Abstract.

"Ocean temperature and dissolved oxygen shape marine habitats in an interplay with species' physiological characteristics. Therefore, the observed and projected warming and deoxygenation of the world's oceans in the 21st century may strongly affect species' habitats. Here, we implement an extended version of the Aerobic Growth Index (AGI), which quantifies whether a viable population of a species can be sustained in a particular location. We assess the impact of projected deoxygenation and warming on the contemporary habitat of 47 representative marine species covering the epipelagic, mesopelagic, and demersal realms. [...]".

 

Source: Biogeosciences
Authors: Anne L. Morée et al.
DOI: https://doi.org/10.5194/bg-20-2425-2023

Read the full article here.


Oceanic anoxic events, photic-zone euxinia, and controversy of sea-level fluctuations during the Middle-Late Devonian

Abstract.

"This paper reviews global records of anoxic events of the Middle Devonian – earliest Mississippian, as well as the possible triggers and controls of these events. These “anoxic events” are complex multistage paleoenvironmental disturbances manifested in multiple proxies, which we showcase with the Horn River Group (HRG) – a succession of basinal organic-rich shales and cherts deposited during the latest Eifelian – earliest Late Frasnian(∼386–373 My ago) on the western continental margin of Laurentia near the paleo-equator. [...]".

 

Source: Science Direct
Authors: Pavel Kabanov et al.
DOI: https://doi.org/10.1016/j.earscirev.2023.104415

Read the full article here.


Phosphorus controls on the formation of vivianite versus green rust under anoxic conditions

Abstract.

"The formation of green rust (GR; a mixed ferric/ferrous hydroxide) and vivianite (ferrous phosphate) are likely to have exerted a major control on phosphorus (P) cycling in ancient anoxic oceans. However, the factors that influence the formation of these minerals under different chemical conditions are poorly constrained, which limits understanding of the pathways that ultimately result in P drawdown and retention in anoxic sediments. This, in turn, limits understanding of P cycling in anoxic oceans and hence potential productivity feedbacks. [...]".

 

Source: Science Direct
Authors: Yijun Xiong et al.
DOI: https://doi.org/10.1016/j.gca.2023.04.032

Read the full article here.


Salinity variations of the inner Yangtze Sea during the Ordovician-Silurian transition and its influences on marginal marine euxinia

Abstract.

"The Ordovician-Silurian transition (OST) is a critical geological interval, during which dramatic climatic, environmental and biological changes occurred. Although expanded euxinic conditions have been regarded as one of the main causes of Late Ordovician mass extinction (LOME), the controls of euxinia remain the topic of debate. In this study, we evaluate the paleosalinity conditions of the inner Yangtze Sea (IYS) during the OST using a combination of paleosalinity proxies (B/Ga, Sr/Ba, and S/TOC). [...]".

 

Source: Science Direct
Authors: Guangyao Cao et al.
DOI: https://doi.org/10.1016/j.gloplacha.2023.104129

Read the full article here.


Survey on ocean oxygen measurements and quality controls

"On behalf of the 'Global Ocean Oxygen Database and Atlas steering committee we are very happy to share a short survey (10 questions, less than 10 minutes).

Ocean oxygen data are a critical part to understand our ocean today and in the future. However, currently there is no common entry point to obtain ocean oxygen data of known quality from the open and coastal ocean, measured from Eulerian and Lagrangian platforms. Within the Ocean Decade Programme 'Global Ocean Oxygen Decade' (GOOD) an effort called 'Global Ocean Oxygen Database and ATlas' (GO2DAT) is trying to change this.

This survey is the first step to implement GO2DAT. We count on your cooperation to identify who, where and how ocean oxygen is measured, what type of quality checks and flags are applied. This information will be indispensable to have ocean oxygen data complying with the FAIR and CARE principles.

Please submit your response by 30 June 2023."


Acute hypoxia induces reduction of algal symbiont density and suppression of energy metabolism in the scleractinian coral Pocillopora damicornis

Abstract. 

"Loss of oxygen in the ocean is accelerating and threatening the coral reef ecosystem. In this study, the impacts of hypoxia on the scleractinian coral Pocillopora damicornis were explored. The algal symbiont density, chlorophyll a + c2 content, energy consumption of corals, as well as energy available and consumption of their symbionts, decreased significantly post hypoxia stress. Meanwhile, the malondialdehyde contents in corals and symbionts, together with the caspase-3 activation level in corals, increased significantly in response to hypoxia stress. [...]".

 

Source: Science Direct
Authors: Kaidian Zhang et al.
DOI: https://doi.org/10.1016/j.marpolbul.2023.114897

Read the full article here.


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