Chapter 13 - The crucial contribution of mixing to present and future ocean oxygen distribution
"The oxygen content of the ocean interior largely results from a balance between respiration and advective ventilation, with only a small contribution from mixing processes. However, two important characteristics, which are key to future oxygen distribution in the ocean, primarily depend on the strength of ocean mixing. The first relates to the oxygen minimum zones (OMZ), which are wide O2-deficient mesopelagic layers inhospitable to most marine macro-fauna. We illustrate how mixing intensity controls the volume[...]".
Source: Science Direct
Authors: Marina Lévy et al.
Rapid ecosystem-scale consequences of acute deoxygenation on a Caribbean coral reef
"Loss of oxygen in the global ocean is accelerating due to climate change and eutrophication, but how acute deoxygenation events affect tropical marine ecosystems remains poorly understood. Here we integrate analyses of coral reef benthic communities with microbial community sequencing to show how a deoxygenation event rapidly altered benthic community composition and microbial assemblages in a shallow tropical reef ecosystem. Conditions associated with the event precipitated coral bleaching and mass mortality, causing a 50% loss of live coral and a shift in the benthic community that persisted a year later. Conversely, the unique taxonomic and functional profile of hypoxia-associated microbes rapidly reverted to a normoxic assemblage[...]".
Source: Nature Communications
Authors: Maggie D. Johnson et al.
Fate of floating plastic debris released along the coasts in a global ocean model
"Marine plastic pollution is a global issue, from the shores to the open ocean. Understanding the pathway and fate of plastic debris is fundamental to manage and reduce plastic pollution. Here, the fate of floating plastic pollution discharged along the coasts is studied by comparing two sources, one based on river discharges and the other on mismanaged waste from coastal populations, using a Lagrangian numerical analysis in a global ocean circulation model. About 1/3 of the particles end up in the open ocean and 2/3 on beaches[...]"
Source: Science Direct
Authors: Fanny Chenillat et al.
A committed fourfold increase in ocean oxygen loss
"Less than a quarter of ocean deoxygenation that will ultimately be caused by historical CO2 emissions is already realized, according to millennial-scale model simulations that assume zero CO2 emissions from year 2021 onwards. About 80% of the committed oxygen loss occurs below 2000 m depth, where a more sluggish overturning circulation will increase water residence times and accumulation of respiratory oxygen demand. According to the model results, the deep ocean will thereby lose more than 10% of its pre-industrial oxygen content even if CO2 emissions and thus global warming[...]".
Source: Nature Communications
Authors: Andreas Oschlies
In oceanography, acoustics and hydrodynamics: An extended coupled (2+1)-dimensional Burgers system
"In oceanography, acoustics and hydrodynamics, people pay attention to the Burgers-type equations for different wave processes, one of which is an extended coupled (2+1)-dimensional Burgers system hereby under investigation. Based on the scaling transformation, Bell polynomials, Hirota operators and symbolic computation, we structure out two hetero-Bäcklund transformations, each of which to a solvable linear partial differential[...]"
Source: Science Direkt
Authors: Xin-YiGao et al.
Paleocene-Eocene volcanic segmentation of the Norwegian-Greenland seaway reorganized high-latitude ocean circulation
"The paleoenvironmental and paleogeographic development of the Norwegian–Greenland seaway remains poorly understood, despite its importance for the oceanographic and climatic conditions of the Paleocene–Eocene greenhouse world. Here we present analyses of the sedimentological and paleontological characteristics of Paleocene–Eocene deposits (between 63 and 47 million years old) in northeast Greenland, and investigate key unconformities and volcanic facies observed through seismic reflection imaging in offshore basins.[...]"
Source: Communications Earth & Environment
Authors: Jussi Hovikoski et al.
Ocean currents as a potential dispersal pathway for Antarctica’s most persistent non-native terrestrial insect
"The non-native midge Eretmoptera murphyi is Antarctica’s most persistent non-native insect and is known to impact the terrestrial ecosystems. It inhabits by considerably increasing litter turnover and availability of soil nutrients. The midge was introduced to Signy Island, South Orkney Islands, from its native South Georgia, and routes of dispersal to date have been aided by human activities, with little known about non-human-assisted methods of dispersal. This study is the first to determine the potential for dispersal of a terrestrial invertebrate species in Antarctica by combining physiological sea water tolerance data with quantitative assessments[...]"
Source: Polar Biology
Authors: Jesamine C. Bartlett et al.
The Thermodynamic Controls on Sulfide Saturation in Silicate Melts with Application to Ocean Floor Basalts
"A thermodynamic model to calculate the sulfide content at sulfide saturation or SCSS of basaltic and intermediate composition silicate melts has been built from four independently measurable thermodynamic entities, namely the standard state Gibbs free energy of the saturation reaction, the “sulfide capacity”, and the activities of FeO in[...]"
Source: AGU- Advancing Earth and Space Science
Authors: Daniel R. Neuville et al.
Recent Developments in Oxygen Minimum Zones Biogeochemistry
New Research Topic: Recent Developments in Oxygen Minimum Zones Biogeochemistry
"Oxygen minimum zones (OMZs) play a key role in carbon, nitrogen and other elemental cycles, and directly impact climate dynamics by influencing air-sea fluxes of the potent greenhouse gases methane and nitrous oxide. Oxygen concentrations, catalyze specialized micro-organisms to regulate chemical fluxes, which are critical for ecosystem functioning. The degree of deoxygenation in the OMZs vary from hypoxic in the tropical Atlantic Ocean to functionally anoxic in the eastern tropical Pacific Ocean and the northern Indian Ocean.[...]"
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Constraint on net primary productivity of the global ocean by Argo oxygen measurements
"The biological transformation of dissolved inorganic carbon to organic carbon during photosynthesis in the ocean, marine primary production, is a fundamental driver of biogeochemical cycling, ocean health and Earth’s climate system. The organic matter created supports oceanic food webs, including fisheries, and is an essential control on atmospheric carbon dioxide levels. Marine primary productivity is sensitive to changes due to climate forcing, but observing the response at the global scale[...]"
Source: Nature Geoscience
Authors: Kenneth S. Johnson et al.