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Heavy iron in large gem diamonds traces deep subduction of serpentinized ocean floor

Abstract.

"Subducting tectonic plates carry water and other surficial components into Earth’s interior. Previous studies suggest that serpentinized peridotite is a key part of deep recycling, but this geochemical pathway has not been directly traced. Here, we report Fe-Ni–rich metallic inclusions in sublithospheric diamonds from a depth of 360 to 750 km with isotopically heavy iron (δ56Fe = 0.79 to 0.90‰) and unradiogenic osmium[...]"

 

Source: AAAS
Authors: Evan M. Smith et al.
DOI: 10.1126/sciadv.abe9773

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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 [...]"

 

Source: Polar Biology
Authors: Jesamine C. Bartlett et al.
DOI:https://doi.org/10.1007/s00300-020-02792-2

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Trends and variability of ocean waves under RCP8.5 emission scenario in the Mediterranean Sea

Abstract.

"Wind-generated ocean waves are key inputs for several studies and applications, both near the coast (coastal vulnerability assessment, coastal structures design, harbor operativity) and off-shore (a.o. oil and gas production, ship routes, and navigation safety). As such, the evaluation of trends in future wave climate is fundamental for the development of efficient policies in the framework of climate change adaptation and mitigation measures. This study focuses[...]"

 

Source: Ocean Dynamics
Authors: Francesco De Leo et al.
DOI: https://doi.org/10.1007/s10236-020-01419-8

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Can seafloor voltage cables be used to study large-scale circulation? An investigation in the Pacific Ocean

Abstract.

"Marine electromagnetic (EM) signals largely depend on three factors: flow velocity, Earth's main magnetic field, and seawater's electrical conductivity (which depends on the local temperature and salinity). Because of this, there has been recent interest in using marine EM signals to monitor and study ocean circulation. Our study utilizes voltage data from retired seafloor telecommunication cables in the Pacific Ocean to examine whether such cables could be used to monitor circulation velocity or transport on large oceanic scales. We process the cable data to isolate the seasonal and monthly variations and then evaluate the correlation between the processed data and numerical predictions of the electric field[...]"

 

Source: EGU-European Geosciences Union
Authors: Jakub Velímský et al.
DOI: https://doi.org/10.5194/os-17-383-2021

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A global viral oceanography database (gVOD)

Abstract.

"Virioplankton are a key component of the marine biosphere in maintaining diversity of microorganisms and stabilizing ecosystems. They also contribute greatly to nutrient cycles/cycling by releasing organic matter after lysis of hosts. In this study, we constructed the first global viral oceanography database (gVOD) by collecting 10 931 viral abundance (VA) data and 727 viral production (VP) data, along with host and relevant oceanographic parameters when available. Most VA data were obtained in the North Atlantic (32 %) and North Pacific (29 %) oceans, while the southeast Pacific[...]"

 

Source: Earth System Science Data 
Authors: Le Xie et al.
DOI: https://doi.org/10.5194/essd-13-1251-2021

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How deep ocean-land coupling controls the generation of secondary microseism Love waves

Abstract.

"Wind driven ocean wave-wave interactions produce continuous Earth vibrations at the seafloor called secondary microseisms. While the origin of associated Rayleigh waves is well understood, there is currently no quantified explanation for the existence of Love waves in the most energetic region of the microseism spectrum (3–10 s). Here, using terrestrial seismic arrays and 3D synthetic acoustic-elastic simulations combined with ocean wave hindcast data, we demonstrate that, observed from land[...]"

 

Source: Nature Communications
Authors: Florian Le Pape et al.
DOI: https://doi.org/10.1038/s41467-021-22591-5

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A committed fourfold increase in ocean oxygen loss

Abstract.

"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 
DOI: https://doi.org/10.1038/s41467-021-22584-4

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A pole-to-equator ocean ousverturning circulation on Encelad

Abstract.

"Enceladus is believed to have a saltwater global ocean, heated at the ocean–core interface and losing heat to the floating ice shell above. This configuration suggests an important role for vertical convection. The ice shell has dramatic meridional thickness variations that, in steady state, must be sustained by the ocean circulation against processes acting to remove these anomalies. This could be achieved through spatially separated regions of freezing and melting at the ocean–ice interface. Here, we use an idealized[...]"

 

Source: Nature Geoscience
Authours: Ana H. Lobo et al.
DOI: https://doi.org/10.1038/s41561-021-00706-3

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Iron isotopes trace primordial magma ocean cumulates melting in Earth’s upper mantle

Abstract.

"The differentiation of Earth ~4.5 billion years (Ga) ago is believed to have culminated in magma ocean crystallization, crystal-liquid separation, and the formation of mineralogically distinct mantle reservoirs. However, the magma ocean model remains difficult to validate because of the scarcity of geochemical tracers of lower mantle mineralogy. The Fe isotope compositions (δ57Fe) of ancient mafic rocks can be used to reconstruct the mineralogy of their mantle source regions. We present Fe isotope data for 3.7-Ga metabasalts from the Isua Supracrustal Belt (Greenland). The δ57Fe signatures[...]"

 

Source: Science Advances
Authors: Helen M. Williams et al.
DOI:10.1126/sciadv.abc7394

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Opposite response of strong and moderate positive Indian Ocean Dipole to global warming

Abstract.

"A strong positive Indian Ocean Dipole (pIOD) induces weather extremes such as the 2019 Australian bushfires and African floods. The impact is influenced by sea surface temperature (SST), yet models disagree on how pIOD SST may respond to greenhouse warming. Here we find increased SST variability of strong pIOD events, with strong equatorial eastern Indian Ocean cool anomalies, but decreased variability of moderate pIOD events, dominated by western warm anomalies[...]"

 

Source: Nature Climate Change
Authors: Wenju Cai et al.
DOI: https://doi.org/10.1038/s41558-020-00943-1

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