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News & Views |
Fidelity of turbidites as earthquake records
Turbidites record ground motion in the 2016 Kaikōura earthquake. Recent events are now revealing how turbidites record earthquakes, but turbidites are triggered in many ways, and testing if ancient turbidites are earthquake-triggered remains challenging.
- Peter J. Talling
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Brief Communication |
Current Atlantic Meridional Overturning Circulation weakest in last millennium
The Atlantic Meridional Overturning Circulation (AMOC) is currently distinctly weaker than it has been for the last millennium, according to a synthesis of proxy records derived from a range of techniques.
- L. Caesar
- , G. D. McCarthy
- & S. Rahmstorf
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Article |
Glacial deep ocean deoxygenation driven by biologically mediated air–sea disequilibrium
Lower than modern dissolved oxygen levels in the deep ocean during the Last Glacial Maximum were the result of greater disequilibrium between the atmosphere and ocean, according to proxy record-constrained Earth system modelling.
- Ellen Cliff
- , Samar Khatiwala
- & Andreas Schmittner
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Article |
Atlantic and Pacific tropics connected by mutually interactive decadal-timescale processes
Atmospheric Walker circulation results in a two-way interaction between decadal-scale sea surface temperature variability in the Atlantic and Pacific, according to pacemaker climate modelling experiments.
- Gerald A. Meehl
- , Aixue Hu
- & Nan Rosenbloom
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Article |
The role of environmental factors in the long-term evolution of the marine biological pump
Ocean temperature and atmospheric oxygen concentration are key factors in the long-term efficiency of the marine biological carbon pump, according to a mechanistic model of carbon transfer from surface waters to the deep ocean interior.
- Mojtaba Fakhraee
- , Noah J. Planavsky
- & Christopher T. Reinhard
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Article |
Recent recovery of Antarctic Bottom Water formation in the Ross Sea driven by climate anomalies
Interacting atmospheric circulation patterns are responsible for a recent reversal of a decades-long decline in deepwater formation on the Antarctic shelf, according to an analysis of in situ and remote sensing data from the Ross Sea.
- Alessandro Silvano
- , Annie Foppert
- & Alison M. Macdonald
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Article |
Biological nitrogen fixation detected under Antarctic sea ice
Observational evidence of cyanobacterial activity in the Antarctic Ocean suggests that nitrogen fixation could be a ubiquitous process in the global ocean.
- Takuhei Shiozaki
- , Amane Fujiwara
- & Naomi Harada
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Article |
Permian–Triassic mass extinction pulses driven by major marine carbon cycle perturbations
The end-Permian mass extinction was linked with ocean acidification due to carbon degassing associated with Siberian Trap emplacement, according to boron isotopes from fossil shells and reconstruction of the carbon cycle.
- Hana Jurikova
- , Marcus Gutjahr
- & Anton Eisenhauer
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Article |
Persistently well-ventilated intermediate-depth ocean through the last deglaciation
Intermediate-depth waters in the Atlantic and Pacific Oceans were well equilibrated with the atmosphere through the last deglaciation, according to radiocarbon data from deep-sea corals.
- Tianyu Chen
- , Laura F. Robinson
- & Karen S. Harpp
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Article |
Coupled Southern Ocean cooling and Antarctic ice sheet expansion during the middle Miocene
Antarctic ice volume expansion in the middle Miocene coincides with Southern Ocean cooling, according to biomarker and clumped isotope temperature records from south of Tasmania.
- Thomas J. Leutert
- , Alexandra Auderset
- & A. Nele Meckler
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Article |
Interannual variations in meltwater input to the Southern Ocean from Antarctic ice shelves
Meltwater entering the Southern Ocean from Antarctic ice shelves varies substantially from year to year, with consequences for Southern Ocean circulation and climate, according to remote sensing estimates of ice-shelf basal melting rates.
- Susheel Adusumilli
- , Helen Amanda Fricker
- & Matthew R. Siegfried
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Review Article |
Materials and pathways of the organic carbon cycle through time
A review of the organic carbon cycle explores the interactions between the Earth’s surface and deeper reservoirs, the expanding inorganic controls on the organic carbon cycle, and how these links have strengthened through geological time.
- Matthieu E. Galvez
- , Woodward W. Fischer
- & Timothy I. Eglinton
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Article |
Last glacial atmospheric CO2 decline due to widespread Pacific deep-water expansion
Carbon-rich Pacific deep water extended into the South Atlantic some 38,000 to 28,000 years ago, potentially contributing to a reduction in atmospheric carbon dioxide and the onset of the Last Glacial Maximum, according to deep-water carbonate chemistry reconstructions.
- J. Yu
- , L. Menviel
- & J. F. McManus
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Article |
Deep-sea eruptions boosted by induced fuel–coolant explosions
Interactions between magma and water can drive explosive fragmentation eruptions of the type seen in the Havre volcanic eruption, New Zealand, in 2012, even under submarine conditions, according to laboratory fragmentation experiments.
- T. Dürig
- , J. D. L. White
- & N. Spitznagel
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Editorial |
The rise of ocean robots
As the COVID-19 pandemic halts many research cruise activities, exploration of the oceans by autonomous vehicles continues, highlighting the strengths of robotic research, but also the limitations.
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Perspective |
Impacts of hydrothermal plume processes on oceanic metal cycles and transport
Characterization of hydrothermal plumes in terms of redox, rather than distance from the vent, illuminates the dominant transport processes and fate of metals, focusing on iron and manganese.
- Amy Gartman
- & Alyssa J. Findlay
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Article |
Chesapeake Bay acidification buffered by spatially decoupled carbonate mineral cycling
Calcium carbonate formed in seagrass beds that is transported and dissolved in deeper waters offshore helps buffer coastal acidification in the Chesapeake Bay, according to geochemical modelling of a transect of carbonate chemistry measurements.
- Jianzhong Su
- , Wei-Jun Cai
- & W. Michael Kemp
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Article |
Abundant nitrite-oxidizing metalloenzymes in the mesopelagic zone of the tropical Pacific Ocean
Continued deoxygenation of the oceans will probably lead to enhanced demand for iron, as implied by the abundance of an iron-rich enzyme in the mesopelagic waters of the Pacific.
- Mak A. Saito
- , Matthew R. McIlvin
- & John B. Waterbury
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Article |
Tropical climate responses to projected Arctic and Antarctic sea-ice loss
Antarctic sea-ice loss causes enhanced warming in the eastern equatorial Pacific, and together with Arctic sea-ice loss accounts for 20–30% of projected warming and rainfall changes in the tropics, suggest climate model simulations.
- Mark R. England
- , Lorenzo M. Polvani
- & Clara Deser
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Article |
Phosphorus-limited conditions in the early Neoproterozoic ocean maintained low levels of atmospheric oxygen
Early Neoproterozoic marine productivity fell due to nutrient drawdown following a switch from an iron-rich to a sulfide-rich ocean, according to records of phosphorus geochemistry measured from sedimentary sections in North China.
- Romain Guilbaud
- , Simon W. Poulton
- & Timothy M. Lenton
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Article |
No state change in pelagic fish production and biodiversity during the Eocene–Oligocene transition
Marine fish biomass and diversity did not change during the Eocene–Oligocene transition despite widespread cooling and Antarctic ice sheet expansion, according to microfossil fish teeth records from a set of deep-sea cores.
- Elizabeth C. Sibert
- , Michelle E. Zill
- & Richard D. Norris
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Article |
Limited Archaean continental emergence reflected in an early Archaean 18O-enriched ocean
The water cycle was in two different steady states, before and after continental emergence, as recorded in the decreasing oxygen isotope values of seawater since the Archaean, according to an inverse geochemical model of the oceanic crustal record.
- Benjamin W. Johnson
- & Boswell A. Wing
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Article |
Bathymetry constrains ocean heat supply to Greenland’s largest glacier tongue
Ocean heat transport underneath the floating tongue of 79 North Glacier, Greenland, is controlled by a sill in the inflow channel, according to ship-based and mooring data as well as bathymetric data.
- Janin Schaffer
- , Torsten Kanzow
- & David H. Roberts
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Article |
Rapid transfer of oxygen to the deep ocean mediated by bubbles
Bubble-mediated flux of oxygen into the Labrador Sea surface ocean contributes to air–sea gas exchange, suggest observations from moored profiling and Argo float data. Climate models that omit the process may underestimate oxygen in the deep ocean.
- D. Atamanchuk
- , J. Koelling
- & D. W. R. Wallace
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News & Views |
Some may like it hot
The biomass of some of the smallest ocean organisms may be stable or even increase in a warming world, suggests a data analysis based on machine-learning techniques.
- Daniele Iudicone
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Article |
Global picophytoplankton niche partitioning predicts overall positive response to ocean warming
Picophytoplankton are partitioned into niches, globally, and their abundance may increase as ocean temperatures rise, suggest analyses of a global abundance dataset with a neural-network-based niche model.
- Pedro Flombaum
- , Wei-Lei Wang
- & Adam C. Martiny
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Article |
Density-compensated overturning in the Labrador Sea
Compensation of the effects of salt and temperature changes on water density in the Labrador Sea can explain the minimal response of the Atlantic overturning circulation to convection, according to analyses of observations and reanalysis data.
- Sijia Zou
- , M. Susan Lozier
- & Laura Jackson
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Article |
Reduced methane seepage from Arctic sediments during cold bottom-water conditions
Methane release rate from Arctic Ocean sediments in winter is significantly lower than in summer, according to surveys of cold-seep activity along the shelf break offshore Svalbard.
- Bénédicte Ferré
- , Pär G. Jansson
- & Helge Niemann
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News & Views |
Changes in the Southern Ocean
Strengthening and poleward movement of the Southern Westerlies, and increased melting of the Antarctic ice sheet play a primary role in changes observed in the Southern Ocean over the past few decades, according to measurements and modelling.
- Alessandro Silvano
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Article |
Importance of wind and meltwater for observed chemical and physical changes in the Southern Ocean
Physical and biogeochemical changes in the Southern Ocean over the past decade are largely due to growing meltwater input and intensifying poleward winds, according to observations from ships and floats and model simulations.
- Ben Bronselaer
- , Joellen L. Russell
- & Jorge L. Sarmiento
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Article |
Climate-forced sea-level lowstands in the Indian Ocean during the last two millennia
Two intervals of distinctly lower Indian Ocean sea level during the last two millennia occurred during times of relatively low incoming solar radiation, according to an analysis of U–Th dated coral microatolls in the Maldives.
- Paul S. Kench
- , Roger F. McLean
- & Keven Roy
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Article |
Extinction intensity during Ordovician and Cenozoic glaciations explained by cooling and palaeogeography
High extinction intensity during Late Ordovician but not Cenozoic transitions to glacial conditions can be attributed to both temperature and palaeogeography, according to analysis combining climate models and simulations of virtual species.
- Erin E. Saupe
- , Huijie Qiao
- & Seth Finnegan
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Article |
Decadal variability in twentieth-century ocean acidification in the California Current Ecosystem
Ocean acidification in the California Current Ecosystem was twice the global average during the past century and influenced by decadal climate variations, according to a record of the calcification rate of planktonic foraminifera from the Santa Barbara Basin.
- Emily B. Osborne
- , Robert C. Thunell
- & Claudia R. Benitez-Nelson
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Article |
Enhanced upward heat transport at deep submesoscale ocean fronts
Deep-reaching, small-scale oceanic fronts can drive upward heat transport from the ocean interior to the surface in eddy-rich regions, suggest satellite and in situ observations of the Antarctic Circumpolar Current.
- Lia Siegelman
- , Patrice Klein
- & Dimitris Menemenlis
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Article |
Heat accumulation on coral reefs mitigated by internal waves
Internal waves can relieve coral reef heat stress, according to an analysis that isolates the effect at different depths using a compilation of high-resolution temperature records.
- Alex S. J. Wyatt
- , James J. Leichter
- & Toshi Nagata
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Article |
Consistent CO2 release by pyrite oxidation on continental shelves prior to glacial terminations
Minimum atmospheric CO2 levels during glacial intervals were set, in part, by repeated CO2 release from pyrite oxidation on exposed continental shelves, according to a geochemical model of the past 3 Myr.
- Martin Kölling
- , Ilham Bouimetarhan
- & Matthias Zabel
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Article |
Global cooling linked to increased glacial carbon storage via changes in Antarctic sea ice
Isolation of deep water around Antarctica due to surface cooling can explain half of the change in atmospheric CO2 levels through glacial–interglacial cycles, according to coupled ocean–sea ice and biogeochemical numerical modelling.
- Alice Marzocchi
- & Malte F. Jansen
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Article |
Reduced continental weathering and marine calcification linked to late Neogene decline in atmospheric CO2
A redistribution of marine calcifiers along with a reduction in weathering led to increased seafloor carbonate deposition during the late Neogene, according to a global compilation of carbonate mass accumulation rate records from sediment cores.
- Weimin Si
- & Yair Rosenthal
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Perspective |
Global-change controls on soil-carbon accumulation and loss in coastal vegetated ecosystems
Coastal vegetated ecosystems have experienced rapid changes in climate and environmental conditions. These changes have caused disturbances to the amount of carbon they store in soils by altering the decomposition process of organic carbon.
- Amanda C. Spivak
- , Jonathan Sanderman
- & Charles S. Hopkinson
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Article |
Sponge skeletons as an important sink of silicon in the global oceans
Inclusion of sponge spicules and radiolarians increases the global ocean biological sink of silicon by 28%, with 95% of that increase attributed to sponges, according to examination of sediments from 17 marine cores.
- Manuel Maldonado
- , María López-Acosta
- & Aude Leynaert
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Article |
West Antarctic ice loss influenced by internal climate variability and anthropogenic forcing
Anthropogenic changes in Antarctic shelf-break winds from the 1920s onwards have contributed to ice loss in the Amundsen Sea, along with natural variability, suggests an analysis of observations and model simulations.
- Paul R. Holland
- , Thomas J. Bracegirdle
- & Eric J. Steig
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Article |
Important contribution of macroalgae to oceanic carbon sequestration
Macroalgae can be transported across the open ocean, and substantial amounts can reach the seafloor at 4,000 m depth, according to analyses of metagenome data from global expeditions. Macroalgae are a potentially important oceanic carbon sink globally.
- Alejandra Ortega
- , Nathan R. Geraldi
- & Carlos M. Duarte
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Article |
Last phase of the Little Ice Age forced by volcanic eruptions
Large volcanic eruptions in the first half of the nineteenth century blurred the transition from the Little Ice Age to anthropogenic warming, and led to sustained cooling, drought in Africa and weakened monsoons, suggests a combination of observations and model simulations.
- Stefan Brönnimann
- , Jörg Franke
- & Christoph C. Raible
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Article |
Common cause for severe droughts in South America and marine heatwaves in the South Atlantic
Droughts in South America and marine heatwaves in the South Atlantic have a common remote cause, convection in the tropical oceans that triggers atmospheric blocking, suggest analyses of observations.
- Regina R. Rodrigues
- , Andréa S. Taschetto
- & Gregory R. Foltz
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Article |
Ross Ice Shelf response to climate driven by the tectonic imprint on seafloor bathymetry
The boundary between West and East Antarctica is a tectonic feature that bisects the Ross Ice Shelf. This boundary constrains ocean circulation under the ice, which affects ice stability, according to airborne survey data and ocean simulations.
- K. J. Tinto
- , L. Padman
- & R. E. Bell
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Article |
Periodic changes in the Cretaceous ocean and climate caused by marine redox see-saw
An internal redox see-saw between the Panthalassa Basin and the proto-North Atlantic can explain cyclic changes in the sediment record throughout the Cretaceous Thermal Maximum 97 to 91 million years ago, according to simulations with a numerical ocean model.
- Klaus Wallmann
- , Sascha Flögel
- & Wolfgang Kuhnt
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Article |
Basal melting of Ross Ice Shelf from solar heat absorption in an ice-front polynya
High melt rates in a key location beneath the Ross Ice Shelf result from a seasonal inflow of water heated in the Ross Sea Polynya, according to in situ observations.
- Craig L. Stewart
- , Poul Christoffersen
- & Julian A. Dowdeswell
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Article |
The floatability of aerosols and wave damping on Titan’s seas
Organic aerosols that sediment from Titan’s atmosphere may float, form a film and damp waves on Titan’s seas, according to computations. This damping effect could explain the observed smoothness of Titan’s seas.
- Daniel Cordier
- & Nathalie Carrasco
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Article |
Proterozoic seawater sulfate scarcity and the evolution of ocean–atmosphere chemistry
In the Proterozoic, sulfate concentrations in the oceans were low and atmospheric methane levels high, according to mass balance and diagenetic models that investigate the oxidation state of the Proterozoic oceans.
- Mojtaba Fakhraee
- , Olivier Hancisse
- & Sergei Katsev