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News & Views |
Butterfly effect of shallow-ocean deoxygenation on past marine biodiversity
A geochemical study of an ancient mass-extinction event shows that only moderate expansion of oxygen-deficient waters along continental margins is needed to decimate marine biodiversity. This finding provides a stark warning of the possible consequences of human-driven ocean deoxygenation on life in Earth’s shallow oceans.
- Brian Kendall
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Article
| Open Access
Globally limited but severe shallow-shelf euxinia during the end-Triassic extinction
While global ocean redox patterns during the end Triassic were similar to today, pulses of localized anoxia were probably linked to mass extinctions on continental shelves, according to analysis of molybdenum records.
- Andrew D. Bond
- , Alexander J. Dickson
- & Bas van de Schootbrugge
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Research Briefing |
Bipolar control on changes in atmospheric carbon dioxide over millennial timescales
Deep-sea acidity data combined with ice-core carbon dioxide records reveal that an interplay between the two polar regions modulates ocean ventilation through various modes. These modes explain past variations in deep-sea carbon storage and atmospheric carbon dioxide on millennial timescales.
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Spatial pattern of marine oxygenation set by tectonic and ecological drivers over the Phanerozoic
Tectonic and ecological factors controlled spatially contrasting marine redox changes through the Phanerozoic, a pattern that was in turn linked to background extinction rates, according to a machine learning-based analysis of shale geochemical data.
- Xiangli Wang
- , Thomas J. Algeo
- & Maoyan Zhu
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Article
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Millennial atmospheric CO2 changes linked to ocean ventilation modes over past 150,000 years
The variable intensity of Southern Ocean as well as North Atlantic deep-water ventilation explains differences in atmospheric CO2 trends and magnitudes during cold stadials over the past 150,000 years, according to a record of deep-ocean acidity.
- J. Yu
- , R. F. Anderson
- & J. F. McManus
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Perspective |
Biogeochemistry of Earth before exoenzymes
Exoenzymes produced by heterotrophic microorganisms early in Earth history helped unlock previously unavailable organic matter and transformed ocean geochemistry.
- Nagissa Mahmoudi
- , Andrew D. Steen
- & Kurt O. Konhauser
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Article |
Recent trends in the chemistry of major northern rivers signal widespread Arctic change
Divergent trends in biogeochemical constituents of the six largest rivers in the Arctic from 2003 to 2019 support multi-faceted changes on the Arctic landscape under global environmental change.
- Suzanne E. Tank
- , James W. McClelland
- & Robert M. Holmes
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Perspective |
Oxygen dynamics in marine productive ecosystems at ecologically relevant scales
The impact of dissolved oxygen fluctuations on marine ecosystems requires consideration of appropriate temporal and spatial scales.
- Folco Giomi
- , Alberto Barausse
- & Marco Fusi
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All Minerals Considered |
Vivianite blues
From Dutch painters to ocean sediments, Caroline Slomp discusses the role vivianite plays in the distribution of phosphorus, an essential nutrient for life.
- Caroline P. Slomp
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Article
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Multi-proxy constraints on Atlantic circulation dynamics since the last ice age
The Atlantic meridional overturning circulation was shallow and weak during the Last Glacial Maximum, and water masses took time to adjust to circulation shifts during the Last Deglaciation, according to a reassessment of proxy records and model simulations.
- Frerk Pöppelmeier
- , Aurich Jeltsch-Thömmes
- & Thomas F. Stocker
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Article
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Oxygenation of the Earth aided by mineral–organic carbon preservation
Iron input into the ocean is a key control on mineral–organic preservation, and therefore the accumulation of oxygen in Earth’s atmosphere, according to a theoretical model and supported by proxy records for iron phases and cycling.
- Mingyu Zhao
- , Benjamin J. W. Mills
- & Caroline L. Peacock
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Article |
Abrupt episode of mid-Cretaceous ocean acidification triggered by massive volcanism
Volcanic activity led to ocean acidification at the onset of Oceanic Anoxic Event 2, which then persisted for 600,000 years due to biogeochemical feedbacks, according to marine osmium isotope and carbonate sedimentation records offshore from southwest Australia.
- Matthew M. Jones
- , Bradley B. Sageman
- & Richard W. Hobbs
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Brief Communication
| Open Access
Recovery from microplastic-induced marine deoxygenation may take centuries
Regional recovery from microplastic pollution-induced marine deoxygenation may take hundreds of years, according to a combination of biogeochemical and microplastic modelling.
- Karin Kvale
- & Andreas Oschlies
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Article |
Rates of seafloor and continental weathering govern Phanerozoic marine phosphate levels
Marine phosphate levels and biological productivity were lowest during the early Phanerozoic when seafloor weathering rates were high and continental weathering rates were muted, according to a statistical model of coupled elemental cycles.
- Shlomit Sharoni
- & Itay Halevy
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Article
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Epipelagic nitrous oxide production offsets carbon sequestration by the biological pump
Substantial nitrous oxide production in the epipelagic zone of the subtropical ocean partially offsets carbon sequestration by the marine biological pump, according to observations from the South China Sea and subtropical northwest Pacific.
- Xianhui S. Wan
- , Hua-Xia Sheng
- & Shuh-Ji Kao
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Article |
Mineral-catalysed formation of marine NO and N2O on the anoxic early Earth
Marine emissions of N2O could have sustained an early Archaean atmosphere of 0.8–6.0 ppb N2O without a protective ozone layer, according to mineral incubations combined with diffusion and photochemical modelling.
- Steffen Buessecker
- , Hiroshi Imanaka
- & Hinsby Cadillo-Quiroz
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Perspective |
Diverse geochemical conditions for prebiotic chemistry in shallow-sea alkaline hydrothermal vents
The spatial and temporal geochemical variability of alkaline hydrothermal systems in shallow waters could support prebiotic chemical reactions required for the emergence of life.
- Laura M. Barge
- & Roy E. Price
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Article |
Negligible atmospheric release of methane from decomposing hydrates in mid-latitude oceans
Methane hydrates decomposing beneath mid-latitude ocean basins are unlikely to be a source of atmospheric methane, according to direct measurements of dissolved methane in the water column from seep fields along the US Atlantic and Pacific margins.
- DongJoo Joung
- , Carolyn Ruppel
- & John D. Kessler
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Article |
The biogeochemical balance of oceanic nickel cycling
Biological uptake in the surface and release in the deep ocean contribute to oceanic nickel distribution, including the residual surface Ni pool, according to culture experiments, field data and global biogeochemical circulation modelling
- Seth G. John
- , Rachel L. Kelly
- & Shun-Chung Yang
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News & Views |
Lingering end to a salinity crisis
Modelling indicates that a return to fully normal marine conditions in the Mediterranean following the flooding that ended the Messinian Salinity Crisis was delayed by salt transfers and temporarily enhanced stratification.
- Angelo Camerlenghi
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Article |
Dissolved organic phosphorus concentrations in the surface ocean controlled by both phosphate and iron stress
Production and consumption of dissolved organic phosphorus in the surface ocean is controlled by the interplay between phosphate and iron stress, according to global analyses of the distribution of marine nutrients.
- Zhou Liang
- , Robert T. Letscher
- & Angela N. Knapp
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Article |
Arctic Ocean’s wintertime mercury concentrations limited by seasonal loss on the shelf
The mercury concentration in the Arctic Ocean is lower and less variable in winter than in summer due to seasonal loss of inorganic mercury on the shelf, according to mercury measurements along a gradient in the northern Barents Sea.
- Stephen G. Kohler
- , Lars-Eric Heimbürger-Boavida
- & Murat V. Ardelan
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Article |
Sea spray as an obscured source for marine cloud nuclei
Very small aerosols from sea spray make up a larger proportion of cloud condensation nuclei than previously recognized, according to an analysis of five years of aerosol ground-based measurement data from over the Atlantic Ocean.
- Wei Xu
- , Jurgita Ovadnevaite
- & Colin O’Dowd
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Matters Arising |
Questioning High Nitrogen Fixation Rate Measurements in the Southern Ocean
- Angelicque E. White
- , Julie Granger
- & Kendra Turk-Kubo
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Article |
Late Ordovician climate change and extinctions driven by elevated volcanic nutrient supply
Increased volcanism-related phosphorus delivery to the Late Ordovician ocean helps explain widespread cooling and eutrophication-driven extinctions, as shown by a biogeochemical model incorporating volcanic ash phosphorus and carbon isotope records.
- Jack Longman
- , Benjamin J. W. Mills
- & Martin R. Palmer
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Article |
End-Permian marine extinction due to temperature-driven nutrient recycling and euxinia
Warming-enhanced microbial respiration can explain marine anoxia patterns across depth, a key driver of the end-Permian mass extinction, according to biogeochemical modelling and geochemical proxy records.
- Dominik Hülse
- , Kimberly V. Lau
- & Andy Ridgwell
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Article |
Sinking enhances the degradation of organic particles by marine bacteria
Faster sinking rates can enhance bacterial degradation of organic particles in the ocean due to flow-induced removal of waste products, according to laboratory experiments and modelling of the marine carbon pump.
- Uria Alcolombri
- , François J. Peaudecerf
- & Roman Stocker
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Article |
Constraint on net primary productivity of the global ocean by Argo oxygen measurements
Argo measurements provide a constrained estimate of net primary productivity of the global ocean of 53 Pg C y–1, according to a global analysis of diel oxygen variations.
- Kenneth S. Johnson
- & Mariana B. Bif
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Article
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Arctic Ocean stratification set by sea level and freshwater inputs since the last ice age
Stratification of the central Arctic Ocean, important for sea-ice persistence, has been controlled by a balance of sea level and freshwater inputs since the last ice age, according to foraminifera-bound nitrogen isotope records that are indicative of surface-water nutrient levels covering the past 35,000 years.
- Jesse R. Farmer
- , Daniel M. Sigman
- & Gerald H. Haug
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News & Views |
Big potential for tiny droplets
Sea spray droplets contribute to the exchange of gases between the oceans and atmosphere. Accounting for this spray-mediated pathway may provide more accurate modelling of air–sea interactions and the ocean response to climate change.
- Magdalena D. Anguelova
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Article |
The role of sea spray in atmosphere–ocean gas exchange
At high winds, above 18 metres per second, sea-spray droplets act as a pathway for atmosphere–ocean gas exchange, especially in regions such as the Southern Ocean, according to a chemically modified microphysical model.
- Allison Staniec
- , Penny Vlahos
- & Edward C. Monahan
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Article |
Circulation-driven variability of Atlantic anthropogenic carbon transports and uptake
Slowdown of the Atlantic Meridional Overturning Circulation from 2004 to 2012 led to a decrease in its relative contribution to North Atlantic carbon accumulation, while the supply from air–sea fluxes increased, according to an analysis of ocean mooring circulation observations.
- Peter J. Brown
- , Elaine L. McDonagh
- & Marie-José Messias
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News & Views |
Dissolution resolution
Analysis of global ocean carbonate chemistry and water mass age information confirms the substantial in situ dissolution of calcium carbonate particles in the upper water column.
- Kitack Lee
- & Richard A. Feely
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Article
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Large subglacial source of mercury from the southwestern margin of the Greenland Ice Sheet
Meltwaters from the southwestern margin of the Greenland Ice Sheet contain exceptionally high concentrations of mercury, exporting up to more than 200 kmol of dissolved mercury every year, suggest mercury measurements from three glacial catchments.
- Jon R. Hawkings
- , Benjamin S. Linhoff
- & Robert G. M. Spencer
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Article |
Calcium carbonate dissolution patterns in the ocean
About 50% of total dissolution of marine calcium carbonate occurs in the water column below 300 m depth while sinking to the seafloor, according to a reconstruction of settling fluxes of calcium carbonate in major oceanic regions from seawater observations.
- Olivier Sulpis
- , Emil Jeansson
- & Jack J. Middelburg
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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 |
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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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 |
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 |
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 |
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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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 |
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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Article |
Fully oxygenated water columns over continental shelves before the Great Oxidation Event
Before the Great Oxidation Event there was regional-scale, full water-column oxygenation above the continental shelf, according to molybdenum and thallium isotope records that indicate massive manganese oxide burial.
- Chadlin M. Ostrander
- , Sune G. Nielsen
- & Ariel D. Anbar
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Article |
Persistent organic matter in oxic subseafloor sediment
A large reservoir of organic carbon persists in oxic pelagic sediments for millions of years as demonstrated by samples from the North Atlantic and South Pacific. This predominantly proteinaceous carbon persists due to physical protection and adsorption to mineral surfaces.
- Emily R. Estes
- , Robert Pockalny
- & Colleen M. Hansel
Mercury fluxes from hydrothermal venting at mid-ocean ridges constrained by measurements