Abstract.

"The methane (CH₄) cycle is a key component of the Earth system that links planetary climate, biological metabolism, and the global biogeochemical cycles of carbon, oxygen, sulfur, and hydrogen. However, currently lacking is a numerical model capable of simulating a diversity of environments in the ocean where CH4 can be produced and destroyed, and with the flexibility to be able to explore not only relatively recent perturbations to Earth’s CH₄ cycle but also to probe CH₄ cycling and associated climate impacts under the very low-O2 conditions characteristic of most of Earth history and likely widespread on other Earth-like planets. [...]"

Source: Geoscientific Model Development
Authors: Christopher T. Reinhard et al.
DOI: 10.5194/gmd-2020-32

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Abstract.

"It is well known that Intermediate Water Masses (IWM) are sinking in high latitudes and ventilate the lower thermocline (500–1500 m depth). We here highlight how the IWM oxygen content and the IWM pathway along the Equatorial Intermediate Current System (EICS) towards the eastern tropical Pacific ocean are essential for the supply of oxygen to the lower thermocline and the Oxygen Minimum Zones (OMZs). [...]"

Source: Ocean Science
Authors: Olaf Duteil et al.
DOI: 10.5194/os-2020-17

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Abstract.

"The hypoxic zone in the northern Gulf of Mexico varies spatially (area, location) and temporally (onset, duration) on multiple scales. Exposure to hypoxic dissolved oxygen (DO) concentrations (< 2 mg L⁻¹) is often lethal and exposure to 2 to 4 mg L⁻¹ often causes the sublethal effects of decreased growth and fecundity on individuals of many fish species. We simulated the movement of individual fish within a high-resolution 3-D coupled hydrodynamic-water quality model (FVCOM-WASP) configured for the northern Gulf of Mexico to examine how spatial variability in DO concentrations would affect fish exposure to hypoxic and sublethal DO concentrations. [...]"

Source: Biogeosciences
Authors: Elizabeth D. LaBone et al.
DOI: 10.5194/bg-2020-51

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"New York / Geneva, 10 March 2020 - The tell-tale physical signs of climate change such as increasing land and ocean heat, accelerating sea level rise and melting ice are highlighted in a new report compiled by the World Meteorological Organization and an extensive network of partners. It documents impacts of weather and climate events on socio-economic development, human health, migration and displacement, food security and land and marine ecosystems. [...]"

Source: World Meteorological Organization (WMO)

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Abstract.

"Ocean deoxygenation driven by global warming and eutrophication is a primary concern for marine life. Resistant animals may be present in dead zone sediments, however there is lack of information on their diversity and metabolism. Here we combined geochemistry, microscopy, and RNA-seq for estimating taxonomy and functionality of micrometazoans along an oxygen gradient in the largest dead zone in the world.  [...]"

Source: Communications Biology
Authors: Elias Broman et al.
DOI: 10.1038/s42003-020-0822-7

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"The fish that live at the bottom of the sea are a hardy bunch. They’re adapted to handle crushing pressure, little to no sunlight, and a meager supply of food. But these otherwise gritty fish are also very sensitive to changes in the climate of the water around them, a new study suggests.

Scientists surveyed different patches of seafloor in the Gulf of California and saw that variations in temperature and oxygen levels had a huge impact on whether the fish community was thriving or sparse. In particular, the researchers found that one specific combination—warmer waters mixed with low oxygen levels—didn’t bode well for deep sea fish. This means that these creatures are likely to be vulnerable to the impacts of climate change, the researchers reported March 5 in Marine Ecology Progress Series. [...]"

Source: Popular Science
 

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Special issue jointly organized between Biogeosciences, Climate of the Past, and Ocean Science.

"The distribution of oxygen in the ocean is controlled by physical, biogeochemical and biological processes. Both the supply and consumption of oxygen are sensitive to climate change in ways that are not fully understood. Recent observations suggest that the oxygen content of the ocean is declining (ocean deoxygenation) and the oxygen minimum zones and costal hypoxia sites are expanding with tremendous effects on the ocean’s ecosystems and living organisms. Following the EUR-OCEANS conference on “Ocean Deoxygenation” in Toulouse, France, in 2011, the 46th International Liège Colloquium on “Low Oxygen Environments in Marine, Fresh and Estuarine Waters” in 2014 and the discussion meeting of the Royal Society London on “Ocean Ventilation and Deoxygenation in a Warming World” in 2016, the purpose of the international conference on “Ocean Deoxygenation: Drivers & Consequences – Past|Present|Future” that took place in Kiel, 3–7 Sept 2018 organised by the Collaborative Research Centre 754 “Climate-Biogeochemical Interactions in the Tropical Ocean” was to − focus on the past, present and future state of oxygen in the ocean on global, regional and local scales − analyse mechanisms and feedbacks critical to identify natural and anthropogenic causes of oxygen variability − determine impacts on biogeochemical cycles and ecosystems. [...]"
 

The issue is closed as of 29^th February 2020. The submissions are listed here.

 

"Fishing boats that drag nets along the sea floor to catch seafood can indiscriminately harm marine life and destroy habitat. Now, a new study suggests “bottom trawling” can also disrupt the ability of microbes in sediment to remove excess nutrients in coastal waters, potentially increasing that pollution. “This is one of the first papers to look at actual biogeochemical effects of bottom trawling,” says Sebastiaan van de Velde, a marine biogeochemist at the University of California, Riverside, who was not involved. “The whole angle is very novel.” [...]"

Source: Science

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"Could pumping oxygen-rich surface water into the depths of lakes, estuaries, and coastal ocean waters help ameliorate dangerous dead zones? New work says yes, although they caution that further research would be needed to understand any possible side effects before implementing such an approach. [...]"

Source: Science Daily 

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Abstract.

"The redox chemistry of anoxic continental margin settings evolved from widespread sulfide-containing (euxinic) conditions to a global ferruginous (iron-containing) state in the early Neoproterozoic era (from ~1 to 0.8 billion years ago). Ocean redox chemistry exerts a strong control on the biogeochemical cycling of phosphorus, a limiting nutrient, and hence on primary production, but the response of the phosphorus cycle to this major ocean redox transition has not been investigated. [...]"

Source: Nature Geoscience
Authors: Romain Guilbaud et al.
DOI: 10.1038/s41561-020-0548-7

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