News

Oxygen declination in the coastal ocean over the twenty-first century: Driving forces, trends, and impacts

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_2001–2018) data comparison of 200 m below the surface water from the first two decades of the 21st century. [...]".

 

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

Read the full article here.


Expanding oxygen minimum zones in the northern Indian Ocean predicted by hypoxia-related bacteria

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

Read the full article here.


Adjusting metabolic rates and critical oxygen tension in planktonic copepods under increasing hypoxia in highly productive coastal upwelling zones

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: Leissing Frederick et al.
DOI: https://doi.org/10.1002/lno.12556

Read the full article here.


The global energy transition offers new options for mitigation of coastal hypoxia: Do we know enough?

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: Patricia Handmann & Douglas Wallace
DOI: https://doi.org/10.1111/gcb.17228

Read the full article here.


Intra-colony spatial variance of oxyregulation and hypoxic thresholds for key Acropora coral species

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: Nicole J. Dilernia et al.
DOI: https://doi.org/10.1002/ece3.11100

Read the full article here.


New approaches to combat eutrophication and hypoxia

"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@unesco.org

More information:

The 'New approaches to combat eutrophication and hypoxia' event

The GEF Clean and Healthy Ocean Program

IOC-UNESCO program announcement


Copepoda community imprints the continuity of the oceanic and shelf oxygen minimum zones along the west coast of India

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–September], 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: Vidhya Vijayasenan et al.
DOI: https://doi.org/10.1016/j.marenvres.2024.106380

Read the full article here.


Decreasing available O2 interacts with light to alter the growth and fatty acid content in a marine diatom

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 ± 10 μmol L−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 ± 7.5 μmol L−1) reduced its growth at any growth lights. [...]".

 

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

Read the full article here.


Enhanced ocean deoxygenation in the Bering Sea during MIS 11c

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 (424–374 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: Science Direct
Authors: Xuguang Feng et al.
DOI: https://doi.org/10.1016/j.palaeo.2023.111982

Read the full article here.


Climate, Oxygen, and the Future of Marine Biodiversity

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 ∼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: Annual Review of Marine Science
Authors: Curtis Deutsch et al.
DOI: https://doi.org/10.1146/annurev-marine-040323-095231

Read the full article here.


Showing 1 - 10 of 125 results.
Items per Page 10
of 13

Newsletter

It is possible to subscribe to our email newsletter list.

Depending on the amount of publications, we will summarize the activities on this blog in a newsletter for everyone not following the blog regularly.

If you want to subscribe to the email list to receive the newsletter, please send an email to sfb754@geomar.de with the header "subscribe".

If you want to unsubscribe from the newsletter, please send an email to sfb754@geomar.de with the header "unsubscribe".

You cannot forward any messages as a regular member to the list. If you want to suggest new articles or would like to contact us because of any other issue, please send an email to sfb754@geomar.de.

GOOD Social Media

To follow GOOD on LinkedIn, please visit here.
 

To follow GOOD on Twitter, please visit here.


To follow GOOD on Blue Sky, please visit here

Upcoming Events

« June 2024 »
8
Global Ocean Oxygen Network on World Ocean Day 2024
12
GO2NE Webinar on Ocean Deoxygenation

Go to all events