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Coral reef survival under accelerating ocean deoxygenation

Abstract.

"Global warming and local eutrophication simultaneously lower oxygen (O2) saturation and increase biological O2 demands to cause deoxygenation. Tropical shallow waters, and their coral reefs, are particularly vulnerable to extreme low O2 (hypoxia) events. These events can drive mass mortality of reef biota; however, they currently remain unaccounted for when considering coral reef persistence under local environmental alterations and global climatic change. In this Perspective, we integrate existing biological, ecological and geochemical[...]"

 

Source: Nature Climate Change
Authors: David J. Hughes et al.
DOI: https://doi.org/10.1038/s41558-020-0737-9

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Phosphorus-limited conditions in the early Neoproterozoic ocean maintained low levels of atmospheric oxygen

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. Here, we use a geochemical[...]"

 

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

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Sea urchin chronicles. The effect of oxygen super-saturation and marine polluted sediments from Bagnoli-Goroglio Bay on different life stages of the

sea urchin Paracentrotus lividus

Abstract.

"In marinas and harbours, the accumulation of pollutants in sediments, combined with poor exchange of water with the open sea, poses a major environmental threat. The presence of photosynthetic organisms and the related oxygen production, however, may alleviate the negative effects of environmental contamination on heterotrophic organisms, enhancing their physiological defences. Furthermore, possible transgenerational buffer effects may increase the ability of natural populations to face environmental[...]"

 

Source: Science Direct
Authors: Antonia Chiarore et al.
DOI: https://doi.org/10.1016/j.marenvres.2020.104967

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Fe isotope composition of Archean sulfides do not record progressive oxygenation of the ocean

Abstract.

"In the history of this continuously evolving planet, the Great Oxygenation Event (GOE), which occurred at ca. 2.3 Ga (Bekker et al., 2004; Holland, 2006) was a critical environmental change. This event was first recognized by the disappearance of detrital uraninite, pyrite, and siderite, from the siliciclastic record, as well as by shales that do not contain appreciable amounts of redox-sensitive elements and paleosols that are not oxidized before ca. 2.3 Ga (Holland, 2006). [...]"

Source: Geology
Authors: Johanna Marin Carbonne
DOI: 10.1130/focus042020.1

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Sinking flux of particulate organic matter in the oceans: Sensitivity to particle characteristics

Abstract.

"The sinking of organic particles produced in the upper sunlit layers of the ocean forms an important limb of the oceanic biological pump, which impacts the sequestration of carbon and resupply of nutrients in the mesopelagic ocean. Particles raining out from the upper ocean undergo remineralization by bacteria colonized on their surface and interior, leading to an attenuation in the sinking flux of organic matter with depth. [...]"

Source: Scientific Reports
Authors: Melissa M. Omand et al.
DOI: 10.1038/s41598-020-60424-5

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Rapid transfer of oxygen to the deep ocean mediated by bubbles

Abstract.

"The concentration of oxygen exerts major controls on life in the ocean, and its distribution in the ocean and atmosphere carries information about biological productivity, transports of mass and heat, ocean deoxygenation and global carbon sinks. Our understanding of processes underlying oxygen distributions, their key features and variability is often lacking. [...]"

Source: Nature Geoscience
Authors: D. Atamanchuk et al.
DOI: 10.1038/s41561-020-0532-2

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Ocean acidification interacts with variable light to decrease growth but increase particulate organic nitrogen production in a diatom

Abstract.

"Phytoplankton in the upper oceans are exposed to changing light levels due to mixing, diurnal solar cycles and weather conditions. Consequently, effects of ocean acidification are superimposed upon responses to variable light levels. We therefore grew a model diatom Thalassiosira pseudonana under either constant or variable light but at the same daily photon dose, with current low (400 μatm, LC) and future high CO2 (1000 μatm, HC) treatments. [...]"

Source: Marine Environmental Research
Authors: Wei Li et al.
DOI: 10.1016/j.marenvres.2020.104965

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Short-term effects of hypoxia are more important than effects of ocean acidification on grazing interactions with juvenile giant kelp

Abstract.

"Species interactions are crucial for the persistence of ecosystems. Within vegetated habitats, early life stages of plants and algae must survive factors such as grazing to recover from disturbances. However, grazing impacts on early stages, especially under the context of a rapidly changing climate, are largely unknown. [...]"

Source: Scientific Reports
Authors: Crystal A. Ng & Fiorenza Micheli 
DOI: 10.1038/s41598-020-62294-3

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Autotrophic Carbon Fixation Pathways Along the Redox Gradient in Oxygen‐Depleted Oceanic Waters

Abstract.

"Anoxic marine zones (AMZs), also known as ‘oxygen‐deficient zones’, contribute to the loss of fixed nitrogen from the ocean by anaerobic microbial processes. While these microbial processes associated with the nitrogen cycle have been extensively studied, those linked to the carbon cycle in AMZs have received much less attention, particularly the autotrophic carbon fixation —a crucial component of the carbon cycle. [...]"

Source: Environmental Microbiology Reports
Authors: Paula Ruiz‐Fernández et al.
DOI: 10.1111/1758-2229.12837

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Warming stimulates sediment denitrification at the expense of anaerobic ammonium oxidation

Abstract.

"Temperature is one of the fundamental environmental variables governing microbially mediated denitrification and anaerobic ammonium oxidation (anammox) in sediments. The GHG nitrous oxide (N2O) is produced during denitrification, but not by anammox, and knowledge of how these pathways respond to global warming remains limited. [...]"

Source: Nature Climate Change
Authors: Ehui Tan et al.
DOI: 10.1038/s41558-020-0723-2

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