News
Ocean currents as a potential dispersal pathway for Antarctica’s most persistent non-native terrestrial insect
Abstract.
"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.
DOI: https://doi.org/10.1007/s00300-020-02792-2
Reconstructing the Preindustrial Coastal Carbon Cycle Through a Global Ocean Circulation Model: Was the Global Continental Shelf Already Both Autotrop
Abstract.
"The contribution of continental shelves to the marine carbon cycle is still poorly understood. Their preindustrial state is, for one, essentially unknown, which strongly limits the quantitative assessment of their anthropogenic perturbation. To date, approaches developed to investigate and quantify carbon fluxes on continental shelves have strongly simplified their physical and biogeochemical features. In this study, we enhance the global ocean biogeochemistry model HAMburg Ocean Carbon Cycle by[...]"
Source: AGU- Advancing Earth and Space Science
Authors: Fabrice Lacroix et al.
DOI: https://doi.org/10.1029/2020GB006603
Impacts of hypoxic events surpass those of future ocean warming and acidification
Abstract.
"Over the past decades, three major challenges to marine life have emerged as a consequence of anthropogenic emissions: ocean warming, acidification and oxygen loss. While most experimental research has targeted the first two stressors, the last remains comparatively neglected. Here, we implemented sequential hierarchical mixed-model meta-analyses (721 control–treatment comparisons) to compare the impacts of oxygen conditions associated with the current and continuously intensifying hypoxic events (1–3.5 O2 mg l−1) with those experimentally yielded by ocean warming (+4 °C) and acidification (−0.4 units) conditions[...]"
Source: Nature Ecology & Evolution
Authors: Eduardo Sampaio et al.
DOI: https://doi.org/10.1038/s41559-020-01370-3
Effect of dissolved oxygen and hydrogen on the stress corrosion cracking behavior of alloy 600 in high temperature water
Abstract.
"The stress corrosion cracking behavior of alloy 600 was studied in high temperature water at 288°C to 360°C. The effects of dissolved oxygen (DO) and dissolved hydrogen (DH) on crack growth rate (CGR) are discussed. Results show that the CGR of alloy 600 in hydrogenated water (at the Ni/NiO phase boundary) is about 2-200 times higher than in 2 ppm O2 oxygenated water at 325°C and 360°C, while the opposite behavior was observed at 288°C. Much more severe intergranular oxidation was observed[...]"
Source: Science Direct
Authors: Jiamei Wang et al.
DOI: https://doi.org/10.1016/j.jnucmat.2020.152603
Impact of the Agulhas Return Current on the oceanography of the Kerguelen Plateau region, Southern Ocean, over the last 40 kyrs
Abstract.
"The oceanography of the western Indian sector of the Southern Ocean is extremely complex due to the presence of several subantartic islands and plateaus that alter the zonal flow of the Antarctic Circumpolar Current. The circulation is even more complex around the Kerguelen Islands (KI) as the hydrological fronts merge with the Agulhas Return Current, the latter transporting warm surface waters from the low latitudes to the Subantarctic Zone (SAZ) east of KI. Here we present new sea-surface and sub-surface temperatures, based on diatom and radiolarian census[...]"
Source: Science Direct
Authors: M.Civel-Mazens et al.
DOI:https://doi.org/10.1016/j.quascirev.2020.106711
Extreme Levels of Ocean Acidification Restructure the Plankton Community and Biogeochemistry of a Temperate Coastal Ecosystem: A Mesocosm Study
Abstract.
"The oceans’ uptake of anthropogenic carbon dioxide (CO2) decreases seawater pH and alters the inorganic carbon speciation – summarized in the term ocean acidification (OA). Already today, coastal regions experience episodic pH events during which surface layer pH drops below values projected for the surface ocean at the end of the century. Future OA is expected to further enhance the intensity of these coastal extreme pH events. To evaluate the influence of such episodic OA events in coastal regions, we deployed eight pelagic mesocosms[...]".
Source: Frontiers
Authors: Carsten Spisla et al.
DOI: https://doi.org/10.3389/fmars.2020.611157
Antarctic icebergs reorganize ocean circulation during Pleistocene glacials
Abstract.
"The dominant feature of large-scale mass transfer in the modern ocean is the Atlantic meridional overturning circulation (AMOC). The geometry and vigour of this circulation influences global climate on various timescales. Palaeoceanographic evidence suggests that during glacial periods of the past 1.5 million years the AMOC had markedly different features from today1; in the Atlantic basin, deep waters of Southern Ocean origin[...]"
Source: Nature
Authors: Aidan Starr et al.
DOI: https://doi.org/10.1038/s41586-020-03094-7
Ocean acidification locks algal communities in a species-poor early successional stage
Abracts.
"Long-term exposure to CO2-enriched waters can considerably alter marine biological community development, often resulting in simplified systems dominated by turf algae that possess reduced biodiversity and low ecological complexity. Current understanding of the underlying processes by which ocean acidification alters biological community development and stability remains limited, making the management of such shifts problematic. Here, we deployed recruitment tiles in reference[...]"
Source: Wiley Online Library
Authors: Ben P. Harvey et al.
DOI: https://doi.org/10.1111/gcb.15455
The Ocean barcode atlas: A web service to explore the biodiversity and biogeography of marine organisms
Abstract.
"The Ocean Barcode Atlas (OBA) is a user friendly web service designed for biologists who wish to explore the biodiversity and biogeography of marine organisms locked in otherwise difficult to mine planetary scale DNA metabarcode data sets. Using just a web browser, a comprehensive picture of the diversity of a taxon or a barcode sequence is visualized graphically on world maps and interactive charts. Interactive results panels allow dynamic threshold adjustments and the display of diversity results[...]"
Source: Wiley Online Library
Authors: Caroline Vernette et al.
DOI: https://doi.org/10.1111/1755-0998.13322
Antioxidant responses of the mussel Mytilus coruscus co-exposed to ocean acidification, hypoxia and warming
Abstract.
"In the present study, the combined effects of pH, dissolved oxygen (DO) and temperature levels on the antioxidant responses of the mussel Mytilus coruscus were evaluated. Mussels were exposed to two pH (8.1, 7.7-acidification), two DO (6 mg L−1, 2 mg L−1-hypoxia) and two temperature levels[...]"
Source: Science Direct
Authors: Fahim Ullah Khan et al
DOI: https://doi.org/10.1016/j.marpolbul.2020.111869
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