Ocean sciences

  • Article
    | Open Access

    Anthropogenic CO2 is acidifying the ocean, but knowledge of the carbonate properties underlying these dynamics in coastal oceans is lacking. Here, the authors reveal spatial distribution patterns and variability in carbonate chemistry along North America’s coasts.

    • Wei-Jun Cai
    • , Yuan-Yuan Xu
    • , Richard A. Feely
    • , Rik Wanninkhof
    • , Bror Jönsson
    • , Simone R. Alin
    • , Leticia Barbero
    • , Jessica N. Cross
    • , Kumiko Azetsu-Scott
    • , Andrea J. Fassbender
    • , Brendan R. Carter
    • , Li-Qing Jiang
    • , Pierre Pepin
    • , Baoshan Chen
    • , Najid Hussain
    • , Janet J. Reimer
    • , Liang Xue
    • , Joseph E. Salisbury
    • , José Martín Hernández-Ayón
    • , Chris Langdon
    • , Qian Li
    • , Adrienne J. Sutton
    • , Chen-Tung A. Chen
    •  & Dwight K. Gledhill
  • Article
    | Open Access

    Every year, hundreds of people die at sea because of vessel accidents, and a key challenge in reducing these fatalities is to make Search and Rescue (SAR) planning more efficient. Here, the authors uncover hidden flow features that attract floating objects, providing specific information for optimal SAR planning.

    • Mattia Serra
    • , Pratik Sathe
    • , Irina Rypina
    • , Anthony Kirincich
    • , Shane D. Ross
    • , Pierre Lermusiaux
    • , Arthur Allen
    • , Thomas Peacock
    •  & George Haller
  • Article
    | Open Access

    Plastic pollution has infiltrated every ecosystem, but few studies have quantified the biogeochemical or ecological effects of plastic. Here the authors show that microplastics in ocean sediment can significantly alter microbial community structure and nitrogen cycling.

    • Meredith E. Seeley
    • , Bongkeun Song
    • , Renia Passie
    •  & Robert C. Hale
  • Article
    | Open Access

    Numerous marine ecosystem models are used to project animal biomass over time but integrating them can be challenging. Here the authors develop a test for statistical significance in multi-model ensemble trends, and thus relate future biomass trends to current patterns of ecological and socioeconomic status.

    • Daniel G. Boyce
    • , Heike K. Lotze
    • , Derek P. Tittensor
    • , David A. Carozza
    •  & Boris Worm
  • Article
    | Open Access

    Previous work suggests that marine oxygen levels and bioturbation are important factors that shape phosphorus burial and the size of the marine biosphere. Here the authors show that seawater calcium concentration is a key factor in controlling marine P burial, and thus the global oxygen cycle.

    • Mingyu Zhao
    • , Shuang Zhang
    • , Lidya G. Tarhan
    • , Christopher T. Reinhard
    •  & Noah Planavsky
  • Article
    | Open Access

    Observations of global ocean heat content during 2005–2015 have shown a strong hemispheric asymmetry, and the southern hemisphere accounts 92% of the total heat gain. Here, the authors show that the rate of observed global ocean warming is consistent with a forced symmetric climate change signal and an asymmetric climate variation for this period.

    • Saurabh Rathore
    • , Nathaniel L. Bindoff
    • , Helen E. Phillips
    •  & Ming Feng
  • Article
    | Open Access

    It is unclear whether rapid climate change will alter the effectiveness of marine reserves. Here Graham et al. use a 20-year time-series from the Seychelles to show that marine reserves may not prevent climate-driven shifts in community composition, and that ecological responses to reserves are substantially altered.

    • Nicholas A. J. Graham
    • , James P. W. Robinson
    • , Sarah E. Smith
    • , Rodney Govinden
    • , Gilberte Gendron
    •  & Shaun K. Wilson
  • Article
    | Open Access

    The non-linear interaction between tide and non-tidal residual impacts current and future extreme water levels. Here, based on 620 gauge records, the authors find a large non-linear interaction in the US East Coast, North Sea and parts of southern Japan, that results in a reduction of extreme sea levels.

    • Arne Arns
    • , Thomas Wahl
    • , Claudia Wolff
    • , Athanasios T. Vafeidis
    • , Ivan D. Haigh
    • , Philip Woodworth
    • , Sebastian Niehüser
    •  & Jürgen Jensen
  • Article
    | Open Access

    Global ocean circulation overturns and starts anew in the North Atlantic, propagating climate signals to the rest of the oceans. Using drifter data, Zou and colleagues re-map the spreading pattern for one of the deep water masses and show the impact of mesoscale processes on that pattern.

    • Sijia Zou
    • , Amy Bower
    • , Heather Furey
    • , M. Susan Lozier
    •  & Xiaobiao Xu
  • Article
    | Open Access

    Global environmental changes threaten many food-producing sectors, including aquaculture. Here the authors show that countries most vulnerable to climate change will probably face the highest antimicrobial resistance in aquaculture-related bacteria, and that infected aquatic animals have higher mortality at warmer temperatures.

    • Miriam Reverter
    • , Samira Sarter
    • , Domenico Caruso
    • , Jean-Christophe Avarre
    • , Marine Combe
    • , Elodie Pepey
    • , Laurent Pouyaud
    • , Sarahi Vega-Heredía
    • , Hugues de Verdal
    •  & Rodolphe E. Gozlan
  • Article
    | Open Access

    Marine heatwaves are threatening ocean ecosystems with increasing frequency, but their seasonal drivers are unknown. Here, the authors determine that summertime blobs of warm temperature anomalies in the Pacific occur as a result of prolonged weakening in the North Pacific High-Pressure System.

    • Dillon J. Amaya
    • , Arthur J. Miller
    • , Shang-Ping Xie
    •  & Yu Kosaka
  • Article
    | Open Access

    Estuaries are diverse and important aquatic ecosystems, yet we lack information on their response to climate change. Here, the authors show that east Australian estuaries are warming and acidifying faster than predicted by ocean or atmospheric models; a trend that is magnified in shallow estuaries.

    • Elliot Scanes
    • , Peter R. Scanes
    •  & Pauline M. Ross
  • Article
    | Open Access

    Corals have evolved as finely tuned light collectors. Here, the authors report on the 3D printing of coral-inspired biomaterials, that mimic the coral-algal symbiosis; these bionic corals lead to dense microalgal growth and can find applications in algal biotechnology and applied coral science.

    • Daniel Wangpraseurt
    • , Shangting You
    • , Farooq Azam
    • , Gianni Jacucci
    • , Olga Gaidarenko
    • , Mark Hildebrand
    • , Michael Kühl
    • , Alison G. Smith
    • , Matthew P. Davey
    • , Alyssa Smith
    • , Dimitri D. Deheyn
    • , Shaochen Chen
    •  & Silvia Vignolini
  • Article
    | Open Access

    The North Atlantic current has been suspected to trigger intrusions of temperate marine species in the Arctic. Here, Oziel and colleagues reveal the link between the poleward intrusion of the temperate coccolithophore Emiliania huxleyi and the North Atlantic current, showing evidence for bio-advection as an important mechanism.

    • L. Oziel
    • , A. Baudena
    • , M. Ardyna
    • , P. Massicotte
    • , A. Randelhoff
    • , J.-B. Sallée
    • , R. B. Ingvaldsen
    • , E. Devred
    •  & M. Babin
  • Article
    | Open Access

    Global atmospheric CO2 varies between glacial–interglacial cycles. Here, the authors study these changes using Si records and how the Si flux and ocean circulation changes controlled the global Si distribution across the last deglaciation, based on high-resolution Si-isotope records from the Indian Sector Southern Ocean.

    • M. Dumont
    • , L. Pichevin
    • , W. Geibert
    • , X. Crosta
    • , E. Michel
    • , S. Moreton
    • , K. Dobby
    •  & R. Ganeshram
  • Article
    | Open Access

    Coastal pollution degrades ecosystems, but long term impacts are unknown in Australia’s Great Barrier Reef. Using a 333 year record of coral skeleton nitrogen isotopes, Erler and colleagues show that increasing nutrient inputs since European settlement have led to unexpected feedback responses.

    • Dirk V. Erler
    • , Hanieh Tohidi Farid
    • , Thomas D. Glaze
    • , Natasha L. Carlson-Perret
    •  & Janice M. Lough
  • Article
    | Open Access

    In this study, the authors show that water flowing through thawed soils below the tundra surface (supra-permafrost groundwater) can be a major source of dissolved organic matter (DOM) to Arctic coastal waters during the summer. This DOM contains leachates from old soil carbon stocks, including potential contributions from thawing permafrost.

    • Craig T. Connolly
    • , M. Bayani Cardenas
    • , Greta A. Burkart
    • , Robert G. M. Spencer
    •  & James W. McClelland
  • Article
    | Open Access

    The authors here combine a range of geophysical data, numerical modelling and borehole data to present a high resolution map of an offshore freshened groundwater system in the Canterbury Bight, New Zealand. The study shows the extensions of the offshore freshened groundwater system to be controlled by high permeability shelf sediments, buried paleochannels and onshore rivers.

    • Aaron Micallef
    • , Mark Person
    • , Amir Haroon
    • , Bradley A. Weymer
    • , Marion Jegen
    • , Katrin Schwalenberg
    • , Zahra Faghih
    • , Shuangmin Duan
    • , Denis Cohen
    • , Joshu J. Mountjoy
    • , Susanne Woelz
    • , Carl W. Gable
    • , Tanita Averes
    •  & Ashwani Kumar Tiwari
  • Article
    | Open Access

    The Southern Ocean is an important sink of carbon via the biological pump. Here authors run high-resolution physical/biogeochemical simulations of an open-Southern Ocean ecosystem forced with a realistic seasonal cycle and confirm that (sub)mesoscale iron transport across the mixing-layer base sustains primary productivity.

    • Takaya Uchida
    • , Dhruv Balwada
    • , Ryan P. Abernathey
    • , Galen A. McKinley
    • , Shafer K. Smith
    •  & Marina Lévy
  • Article
    | Open Access

    Eddies are common ocean features that isolate large swaths of seawater, but it is unclear how they influence productivity of phytoplankton trapped inside. Here Ellwood and colleagues use stable and radiogenic isotopes to characterize a Southern Ocean eddy, finding vanishingly low iron concentrations that drive low productivity across the region.

    • Michael J. Ellwood
    • , Robert F. Strzepek
    • , Peter G. Strutton
    • , Thomas W. Trull
    • , Marion Fourquez
    •  & Philip W. Boyd
  • Article
    | Open Access

    Biogeographic patterns of genetic diversity are poorly documented, especially for fish species. Here the authors show that (mitochondrial) genetic diversity has global spatial organization patterns with different environmental drivers for marine and freshwater fishes, where genetic diversity is only partly congruent with species richness.

    • Stéphanie Manel
    • , Pierre-Edouard Guerin
    • , David Mouillot
    • , Simon Blanchet
    • , Laure Velez
    • , Camille Albouy
    •  & Loïc Pellissier
  • Article
    | Open Access

    The freshwater content of the Beaufort Gyre in the Western Arctic Ocean has increased in response to almost two decades of persistent anti-cyclonic winds. Here, the authors found that dramatic loss of sea ice and acceleration of surface currents after 2007 led to a net annual wind energy input to the Beaufort Gyre, and anticipate that continued sea ice decline will lead to an increasingly energetic Beaufort Gyre.

    • Thomas W. K. Armitage
    • , Georgy E. Manucharyan
    • , Alek A. Petty
    • , Ron Kwok
    •  & Andrew F. Thompson
  • Article
    | Open Access

    What drives hydroclimate changes in tropical regions is not well known. Here, the authors present a 12,000 year long precipitation record from Guetemala which shows that exceeding a threshold in sea surface temperatures caused Central American rainfall to change from a dry to an active convective regime around 9000 years ago.

    • Amos Winter
    • , Davide Zanchettin
    • , Matthew Lachniet
    • , Rolf Vieten
    • , Francesco S. R. Pausata
    • , Fredrik Charpentier Ljungqvist
    • , Hai Cheng
    • , R. Lawrence Edwards
    • , Thomas Miller
    • , Sara Rubinetti
    • , Angelo Rubino
    •  & Carla Taricco
  • Article
    | Open Access

    Tropical cyclones can cause severe damage, in particular through flooding of coastal areas. Here, the authors show that in addition to known impacts, tropical cyclone rainbands can cause meteotsunami waves that can contribute significantly to the total water levels and hence flooding risks.

    • Luming Shi
    • , Maitane Olabarrieta
    • , David S. Nolan
    •  & John C. Warner
  • Article
    | Open Access

    The Atlantic Ocean overturning circulation is important to the global climate system. Here the authors show that eastern subpolar North Atlantic underwent extreme freshening during 2012 to 2016, with a magnitude never seen before in 120 years of surface measurements.

    • N. Penny Holliday
    • , Manfred Bersch
    • , Barbara Berx
    • , Léon Chafik
    • , Stuart Cunningham
    • , Cristian Florindo-López
    • , Hjálmar Hátún
    • , William Johns
    • , Simon A. Josey
    • , Karin Margretha H. Larsen
    • , Sandrine Mulet
    • , Marilena Oltmanns
    • , Gilles Reverdin
    • , Tom Rossby
    • , Virginie Thierry
    • , Hedinn Valdimarsson
    •  & Igor Yashayaev
  • Article
    | Open Access

    The influence of the Congo River margin on surface Fe concentrations is understudied. Here the authors show that such influence is evident over 1000 km from the Congo outflow.

    • Lúcia H. Vieira
    • , Stephan Krisch
    • , Mark J. Hopwood
    • , Aaron J. Beck
    • , Jan Scholten
    • , Volker Liebetrau
    •  & Eric P. Achterberg
  • Article
    | Open Access

    Predator-prey interactions play important roles in the cycling of marine organic matter. Here the authors show that a Gram-negative bacterium isolated from marine sediments can kill and feed on Gram-positive bacteria by secreting a peptidoglycan-degrading enzyme.

    • Bai-Lu Tang
    • , Jie Yang
    • , Xiu-Lan Chen
    • , Peng Wang
    • , Hui-Lin Zhao
    • , Hai-Nan Su
    • , Chun-Yang Li
    • , Yang Yu
    • , Shuai Zhong
    • , Lei Wang
    • , Ian Lidbury
    • , Haitao Ding
    • , Min Wang
    • , Andrew McMinn
    • , Xi-Ying Zhang
    • , Yin Chen
    •  & Yu-Zhong Zhang
  • Article
    | Open Access

    Increasingly, eDNA is being used to infer ecological interactions. Here the authors sample eDNA over 18 months in a marine environment and use co-occurrence network analyses to infer potential interactions among organisms from microbes to mammals, testing how they change over time in response to oceanographic factors.

    • Anni Djurhuus
    • , Collin J. Closek
    • , Ryan P. Kelly
    • , Kathleen J. Pitz
    • , Reiko P. Michisaki
    • , Hilary A. Starks
    • , Kristine R. Walz
    • , Elizabeth A. Andruszkiewicz
    • , Emily Olesin
    • , Katherine Hubbard
    • , Enrique Montes
    • , Daniel Otis
    • , Frank E. Muller-Karger
    • , Francisco P. Chavez
    • , Alexandria B. Boehm
    •  & Mya Breitbart
  • Article
    | Open Access

    In this study, the authors use planktic foraminiferal data to reconstruct ocean carbonate chemistry and temperature from 16.5 to 11 Ma from a size in the tropical eastern Indian Ocean to look at the causes of the Monterey Excursion (ME). They find a positive relationship between dissolved inorganic (DIC) carbon and the ME and a negative one for DIC and the carbon maxima events.

    • S. M. Sosdian
    • , T. L. Babila
    • , R. Greenop
    • , G. L. Foster
    •  & C. H. Lear
  • Article
    | Open Access

    The relationship between the coral animal and symbiotic algae is essential to coral health, and researchers are turning to Exaiptasia, a model cnidarian system, to study this relationship mechanistically. Here the authors find that endosymbiotic algae become limited by nitrogen at high population densities and provide the host with high levels of fixed carbon.

    • Tingting Xiang
    • , Erik Lehnert
    • , Robert E. Jinkerson
    • , Sophie Clowez
    • , Rick G. Kim
    • , Jan C. DeNofrio
    • , John R. Pringle
    •  & Arthur R. Grossman
  • Article
    | Open Access

    Recent recession of the Larsen Ice Shelf C has revealed that microbial alteration of illite can occur within marine sediments, a process previously thought to only occur abiotically during low-grade metamorphism. Here, the authors show that such microbial alteration of illite could provide a potential source of Fe release to Southern Ocean waters during Holocene glacial cycles.

    • Jaewoo Jung
    • , Kyu-Cheul Yoo
    • , Brad E. Rosenheim
    • , Tim M. Conway
    • , Jae Il Lee
    • , Ho Il Yoon
    • , Chung Yeon Hwang
    • , Kiho Yang
    • , Christina Subt
    •  & Jinwook Kim
  • Article
    | Open Access

    Existing fibers beneath the world’s oceans can in principle be used as seismic sensors, but the full potential of this possibility has yet to be explored. Here, the authors demonstrate the feasibility of distributed acoustic sensing in a coastal fiber as a sensor for earthquakes and wave phenomena.

    • A. Sladen
    • , D. Rivet
    • , J. P Ampuero
    • , L. De Barros
    • , Y. Hello
    • , G. Calbris
    •  & P. Lamare
  • Article
    | Open Access

    The Nd isotope composition of seawater has been used to reconstruct past changes in the various contributions of different water masses to the deep ocean, with the isotope signatures of endmember water masses generally assumed to have been stable during the Quaternary. Here, the authors show that deep water produced in the North Atlantic had a significantly more radiogenic Nd signature during the Last Glacial Maximum compared to today.

    • Ning Zhao
    • , Delia W. Oppo
    • , Kuo-Fang Huang
    • , Jacob N. W. Howe
    • , Jerzy Blusztajn
    •  & Lloyd D. Keigwin
  • Article
    | Open Access

    Distributed acoustic sensing (DAS) technology in geophysics is commonly known for applications such as active source seismic profiling in boreholes. Here, the authors convert the fiber optics cable into an ocean bottom seismic recording array with thousands of single component channels.

    • Ethan F. Williams
    • , María R. Fernández-Ruiz
    • , Regina Magalhaes
    • , Roel Vanthillo
    • , Zhongwen Zhan
    • , Miguel González-Herráez
    •  & Hugo F. Martins
  • Article
    | Open Access

    Earth’s carbon cycle and oceanic magnesium cycle are controlled by processes such as weathering, volcanism and precipitation of carbonates, such as dolomite. Here, the authors contradict the view that modern dolomite formation is rare and suggest instead that dolomite accounts for ~40–60% of the global oceanic Mg output in the last 20 Ma.

    • Netta Shalev
    • , Tomaso R. R. Bontognali
    • , C. Geoffrey Wheat
    •  & Derek Vance
  • Review Article
    | Open Access

    The recent collapses of ice shelves in Antarctica due to warming make it essential to understand past ice shelf conditions and mechanisms. Here Smith and colleagues review the latest progress in deciphering the geological imprint of Antarctic ice shelves via sediments, landforms and proxy indicators.

    • James A. Smith
    • , Alastair G. C. Graham
    • , Alix L. Post
    • , Claus-Dieter Hillenbrand
    • , Philip J. Bart
    •  & Ross D. Powell
  • Article
    | Open Access

    Carbon dioxide removal technologies are often touted as a potential strategy to combat ocean acidification. However, the authors show here that these strategies are only effective when included as part of aggressive and rapid climate-action, undermining the idea of geoengineering as a panacea.

    • M. Hofmann
    • , S. Mathesius
    • , E. Kriegler
    • , D. P. van Vuuren
    •  & H. J. Schellnhuber
  • Article
    | Open Access

    Ross Sea Bottom Water, a major source of Antarctic Bottom Water, has experienced significant freshening in recent decades. Here the authors use 23 years of summer measurements to document temporal variability in the salinity of the Ross Sea High Salinity Shelf Water (HSSW) and found that HSSW salinity decreased between 1995 and 2014 and rebounded sharply after 2014.

    • Pasquale Castagno
    • , Vincenzo Capozzi
    • , Giacomo R. DiTullio
    • , Pierpaolo Falco
    • , Giannetta Fusco
    • , Stephen R. Rintoul
    • , Giancarlo Spezie
    •  & Giorgio Budillon
  • Article
    | Open Access

    Healthy coral reefs have an acoustic signature known to be attractive to coral and fish larvae during settlement. Here the authors use playback experiments in the field to show that healthy reef sounds can increase recruitment of juvenile fishes to degraded coral reef habitat, suggesting that acoustic playback could be used as a reef management strategy.

    • Timothy A. C. Gordon
    • , Andrew N. Radford
    • , Isla K. Davidson
    • , Kasey Barnes
    • , Kieran McCloskey
    • , Sophie L. Nedelec
    • , Mark G. Meekan
    • , Mark I. McCormick
    •  & Stephen D. Simpson
  • Article
    | Open Access

    Iron is critical for fueling marine primary productivity, but its concentration is often vanishingly low in the ocean. Here, the authors show that though icebergs serve as vehicles delivering the largest supply of iron to polar oceans, the amount of iron they carry varies widely.

    • Mark J. Hopwood
    • , Dustin Carroll
    • , Juan Höfer
    • , Eric P. Achterberg
    • , Lorenz Meire
    • , Frédéric A. C. Le Moigne
    • , Lennart T. Bach
    • , Charlotte Eich
    • , David A. Sutherland
    •  & Humberto E. González
  • Article
    | Open Access

    Deciphering the origin, age, and composition of deep marine organic carbon remains a challenge for understanding the dynamics of the marine carbon cycle. Here, the authors identify (sub)micron-sized graphite emanating from both high and low temperature hydrothermal vents along the East Pacific Rise, and suggest graphite is a source of old carbon in the deep ocean.

    • Emily R. Estes
    • , Debora Berti
    • , Nicole R. Coffey
    • , Michael F. Hochella Jr.
    • , Andrew S. Wozniak
    •  & George W. Luther III
  • Article
    | Open Access

    Rivers are thought to be the largest source of the recalcitrant and abundant black carbon in the ocean. Here, Wagner and colleagues find distinct pools of black carbon between rivers and the open ocean, challenging the long-held assumption that marine black carbon is of terrestrial origin.

    • Sasha Wagner
    • , Jay Brandes
    • , Robert G. M. Spencer
    • , Kun Ma
    • , Sarah Z. Rosengard
    • , Jose Mauro S. Moura
    •  & Aron Stubbins
  • Article
    | Open Access

    Iron is crucial for marine photosynthesis, but observational constraints on the magnitude of key iron cycle processes are lacking. Here the authors use a range of observational data sets to demonstrate that the balance between iron re-supply and removal in the subsurface controls upper ocean iron limitation.

    • Alessandro Tagliabue
    • , Andrew R. Bowie
    • , Timothy DeVries
    • , Michael J. Ellwood
    • , William M. Landing
    • , Angela Milne
    • , Daniel C. Ohnemus
    • , Benjamin S. Twining
    •  & Philip W. Boyd
  • Article
    | Open Access

    The California Current System is characterized by wind-driven upwelling and by rich mesoscale eddy activity, resulting in a highly productive ecosystem. Here the authors show that offshore cyclonic eddies which were generated near the coast contain higher carbon concentrations in their interior than eddies of the same amplitude generated locally offshore.

    • Caitlin M. Amos
    • , Renato M. Castelao
    •  & Patricia M. Medeiros
  • Article
    | Open Access

    The loss of anomalous sulfur isotope compositions from sedimentary rocks has been considered a symptom of permanent atmospheric oxygenation. Here the authors show sulfur and oxygen isotope evidence from < 2.31 Ga sedimentary barium sulphates (barites) from the Turee Creek Basin, W. Australia, demonstrating the influence of local non-atmospheric processes on anomalous sulfur isotope signals.

    • B. A. Killingsworth
    • , P. Sansjofre
    • , P. Philippot
    • , P. Cartigny
    • , C. Thomazo
    •  & S. V. Lalonde
  • Review Article
    | Open Access

    Swarms of crustaceans called krill dominate Antarctic ecosystems, yet their influence on biogeochemical cycles remains a mystery. Here Cavan and colleagues review the role of krill in the Southern Ocean, and the impact of the krill fishery on ocean fertilisation and the carbon sink.

    • E. L. Cavan
    • , A. Belcher
    • , A. Atkinson
    • , S. L. Hill
    • , S. Kawaguchi
    • , S. McCormack
    • , B. Meyer
    • , S. Nicol
    • , L. Ratnarajah
    • , K. Schmidt
    • , D. K. Steinberg
    • , G. A. Tarling
    •  & P. W. Boyd
  • Article
    | Open Access

    The marginal interaction zones of oceans are understudied. Here, the authors analyse seismic observations of temporal changes at the interface between thermocline layers in the Panama Basin, that reveal a critical mixing state in which turbulent diffusion is gradually replaced by double-diffusion as the dominant mixing process.

    • Qunshu Tang
    • , Vincent C. H. Tong
    • , Richard W. Hobbs
    •  & Miguel Ángel Morales Maqueda
  • Article
    | Open Access

    Iron fertilisation of the high latitude oceans is a well-established biological mechanism to explain the ice age drawdown of atmospheric CO2, yet modelling has so far struggled to account for a sufficient drawdown via this mechanism. Here, the authors propose that N2 fixers, which inhabit the lower latitude ocean, made a significant contribution to CO2 drawdown and so amplified the global response to iron fertilisation during ice ages.

    • Pearse J. Buchanan
    • , Zanna Chase
    • , Richard J. Matear
    • , Steven J. Phipps
    •  & Nathaniel L. Bindoff
  • Article
    | Open Access

    The ocean emits the greenhouse gas methane, but its vastness renders estimations challenging. Here the authors use machine learning to map global ocean methane fluxes, finding a disproportionate contribution from shallow coastal waters, and a link between primary production and methane cycling.

    • Thomas Weber
    • , Nicola A. Wiseman
    •  & Annette Kock