Ocean sciences

  • 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
    •  & 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
    •  & 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
    •  & 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
    •  & 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
  • Article
    | Open Access

    Little is known about the long-term dynamics of mesopelagic fish despite their large contribution to total fish biomass. Here, the authors analyze the Santa Barbara Basin otolith record and suggest that mesopelagic fish populations were large but fluctuated with surface climate over the last ~2000 years.

    • William A. Jones
    •  & David M. Checkley Jr.
  • Article
    | Open Access

    Marine chemistry during the Early Earth (over 2.7 billion years ago) is commonly inferred to have been inorganically sulfate-reducing. Here, the authors argue that organic sulfur cycling may have played a previously unrecognized, yet important, role in the formation of ancient Archean marine sulfides.

    • Mojtaba Fakhraee
    •  & Sergei Katsev
  • Article
    | Open Access

    The nature of erosion featured at the outlet of submarine channels is still a topic of debate. Here the authors present, based on scaled experiments, a novel flow mechanism for turbidity currents at the end of submarine channels and for the first time describe their erosional character.

    • F. Pohl
    • , J. T. Eggenhuisen
    •  & M. J. B. Cartigny
  • Article
    | Open Access

    The oceanic magnesium cycle is closely linked to Earth’s carbon cycle and long-term climate change, due to processes such as continental weathering and authigenic mineral formation. Here, the authors update the global oceanic magnesium budget by quantifying the flux of magnesium from oceans to marine sediments and the associated isotopic fractionation.

    • Richard D. Berg
    • , Evan A. Solomon
    •  & Fang-Zhen Teng
  • Article
    | Open Access

    Anthropogenic CO2 emissions are causing ocean acidification, which can affect the physiology of some organisms. Here, Botté et al. use metagenomics to show differences in metabolic potential between sponge microbiomes sampled at a shallow volcanic CO2 seep and those from nearby control sites.

    • Emmanuelle S. Botté
    • , Shaun Nielsen
    •  & Nicole S. Webster
  • Article
    | Open Access

    During the Miocene, the Central American seaway was not closed, allowing low-salinity Pacific water to potentially weaken the Atlantic circulation. A new, continuous Nd isotope record shows that there was no direct intermediate water mass export from the Caribbean to the Florida Strait and thus, the Atlantic circulation could strengthen.

    • Valeriia Kirillova
    • , Anne H. Osborne
    •  & Martin Frank
  • Article
    | Open Access

    Tropical cyclone-induced coastal flooding will increase under climate change. Here the authors estimate the effects of sea level rise and tropical cyclone climatology change on late–21st–century flood hazards along the US Atlantic and Gulf Coasts and find that the effect of tropical cyclone change could surpass the effect of sea level rise at some areas in the Gulf of Mexico.

    • Reza Marsooli
    • , Ning Lin
    •  & Kairui Feng
  • Article
    | Open Access

    While it is known that the El Niño–Southern Oscillation (ENSO) influences tropical cyclones, but little is known about a reverse effect. Here, data and model output shows that tropical cyclones can affect ENSO with a lead of 3 months, especially contributing to a significantly more intense El Niño in the winter months.

    • Qiuyun Wang
    • , Jianping Li
    •  & Yidan Xu
  • Article
    | Open Access

    Ocean acidification is expected to have a negative impact on calcifying organisms, however, our understanding of the acclimation potential of corals in their natural habit is currently limited. Here, the authors find that scleractinian corals living in high pCO2 conditions cannot fully adapt the chemistry of their internal calcifying fluid compared to corals growing in ambient conditions.

    • M. Wall
    • , J. Fietzke
    •  & A. Paytan
  • Review Article
    | Open Access

    Subseafloor microbial activities are central to global biogeochemical cycles, affecting Earth’s surface oxidation, ocean chemistry, and climate. Here the authors review present understanding of subseafloor microbes and their activities, identify research gaps, and recommend approaches to fill those gaps.

    • Steven D’Hondt
    • , Robert Pockalny
    •  & Arthur J. Spivack
  • Article
    | Open Access

    Climate change is increasing the flow of freshwater to the ocean, yet study of salinity shifts is hampered by a lack of data. Here the authors show that the flux of salt through the ocean rivals that of freshwater inputs and leads to a layered structure of global salinity changes over the past twenty years.

    • Chao Liu
    • , Xinfeng Liang
    •  & Ou Wang
  • Article
    | Open Access

    El Niño warms the tropical Atlantic, which in turn induces an anomalous Rossby wave train, triggering Arctic sea-ice growth and Eurasian warming in the El Niño decay year. This teleconnection via the tropical Atlantic and the Arctic in La Niña decay year contributes to Eurasian cold winter extremes.

    • Shinji Matsumura
    •  & Yu Kosaka
  • Article
    | Open Access

    Prior to the expansion of life on to land, abiotic weathering may have resulted in different boundary conditions affecting the composition of the biosphere. Here the authors studied clay minerals from a Precambrian rock record to reveal the weathering processes and find difference in weathering produced minerals preserved in the Mesoproterozoic Velkerri Formation.

    • Mehrnoush Rafiei
    •  & Martin Kennedy
  • Article
    | Open Access

    Observation systems are not sufficient to determine the relationship between mélange strength and calving frequency. Here the authors used the derivation of digital elevation models from radar interferometry data to study Jakobshavn Isbræ and show an inverse correlation between mélange thickness and calving rate.

    • Surui Xie
    • , Timothy H. Dixon
    •  & Irena Vaňková
  • Article
    | Open Access

    Coral fossils can record climatic history, but teasing apart environmental signals remains a challenge. Here the authors show that crystallographic changes in coral skeletons grown under high CO2 conditions could be used as a sensitive pH proxy, enabling measurement of ocean acidification back in time.

    • Ismael Coronado
    • , Maoz Fine
    •  & Jarosław Stolarski
  • Article
    | Open Access

    The ocean’s swirling eddies are known to influence primary productivity, yet understanding of these processes has been hampered by a lack of resolution. Here the authors combine in-situ drifter, altimeter-based feature tracking, and satellite chlorophyll data to quantify how phytoplankton respond to surface mesoscale phenomena across the globe.

    • Zhengguang Zhang
    • , Bo Qiu
    •  & Seth Travis
  • Article
    | Open Access

    Impacts from marine heatwaves can be devastating, but understanding their causes is largely based on case studies. Here the authors carry out a global assessment of literature and sea surface temperatures to identify important local processes, climate modes and teleconnections that drive marine heatwaves regionally.

    • Neil J. Holbrook
    • , Hillary A. Scannell
    •  & Thomas Wernberg
  • Article
    | Open Access

    The relative importance of crustal vs. anthropogenic dust deposition for iron cycling in the surface ocean is unclear. Based on analysis of iron isotope data from North Atlantic aerosol samples, the authors can reveal the relative importance of anthropogenic iron emissions and its impact on marine biogeochemistry.

    • Tim M. Conway
    • , Douglas S. Hamilton
    •  & Seth G. John
  • Article
    | Open Access

    Hydrothermal activity is recognized to be significant in regulating the dynamics of trace elements in the ocean. Here the authors report the first observational evidence of upwelled hydrothermally influenced deep waters stimulating massive phytoplankton blooms in the Southern Ocean.

    • Mathieu Ardyna
    • , Léo Lacour
    •  & Hervé Claustre
  • Article
    | Open Access

    Artisanal fish fences are used for fishing along many tropical coastlines. Here, Exton et al. examine the impact footprint of artisanal fish fences, showing that they are highly non-selective, cause direct harm across the tropical seascape, disrupt ecological connectivity and create social conflict.

    • Dan A. Exton
    • , Gabby N. Ahmadia
    •  & David J. Smith
  • Article
    | Open Access

    The geography of deep-ocean mixing driven by internal tides is poorly constrained in ocean models. Here the authors unveil the global variability of energetic small-scale internal tides, combining an analytical model with satellite and in situ observations, paving the way to future parameterisations.

    • Clément Vic
    • , Alberto C. Naveira Garabato
    •  & Gordon R. Stephenson
  • Article
    | Open Access

    The freshwater surface layer from the south China seas weakens the Indonesian throughflow during boreal winter, but the impact of the monsoon water cycle of the maritime continent on this freshwater plug is unknown. Here the authors use satellite observations to show a direct link between the regional water cycle in the maritime continent and the freshwater plug.

    • Tong Lee
    • , Séverine Fournier
    •  & Janet Sprintall
  • Article
    | Open Access

    Rising anthropogenic CO2 levels in the atmosphere are resulting in ocean acidification which may impact coral growth rates. Here, the authors quantify the relationship between water depth and δ13C compositions of South Pacific corals from the pre-industrial era, and their results should lead to improvements in the precision of sea level reconstructions using fossil corals.

    • Braddock K. Linsley
    • , Robert B. Dunbar
    •  & Gerard M. Wellington
  • Article
    | Open Access

    Large uncertainty exists in projecting future 20-year global warming trends due to intrinsic tropical Pacific climate variability. Here the authors show that knowledge of the state of the Pacific Ocean can significantly reduce this uncertainty via the use of initialized decadal climate forecasts.

    • Mohammad Hadi Bordbar
    • , Matthew H. England
    •  & Mojib Latif
  • Article
    | Open Access

    The biological pump is the key ecological component that links carbon and energy flow from oceanic surface waters to the abyss. Here the authors show that the elemental composition and energy content of sinking particulate matter can be used to develop a more comprehensive understanding of energy flow networks in the sea.

    • Eric Grabowski
    • , Ricardo M. Letelier
    •  & David M. Karl
  • Article
    | Open Access

    Microbes structure biogeochemical cycles and food webs in the marine environment. Here, the authors sample coral reef-associated microbes across a 24-hour period, showing clear day–night patterns of microbial populations and thus calling for more studies to consider temporal variation in microbiomes at this scale.

    • Linda Wegley Kelly
    • , Craig E. Nelson
    •  & Forest Rohwer
  • Article
    | Open Access

    While several studies have documented early warning signals of population collapse, the use of such signals as indicators of population recovery has not been investigated. Here the authors use models and empirical fisheries data to show that there are statistical indicators preceding recovery of cod populations.

    • Christopher F. Clements
    • , Michael A. McCarthy
    •  & Julia L. Blanchard
  • Article
    | Open Access

    A better understanding of typhoon–ocean interactions is critical for improving typhoon forecasts. Here the authors use data from two buoys that captured Super Typhoon Nepartak and combine it with numerical simulations to reveal the role of enhanced velocity shear in rapid upper-ocean cooling.

    • Yiing Jang Yang
    • , Ming-Huei Chang
    •  & Ching-Ling Wei
  • Article
    | Open Access

    Here the authors holistically examine prokaryote communities associated with diverse coral reef hosts, including sponges, nudibranchs, sea cucumbers, and corals. The results show that sponges have a relatively low diversity of prokaryotes, most of which are shared across a wide range of host taxa rather than being sponge-specific.

    • Daniel F. R. Cleary
    • , Thomas Swierts
    •  & Nicole J. de Voogd
  • Article
    | Open Access

    Findings regarding the impacts of ocean acidification (OA) on the growth and N2 fixation of Trichodesmium are conflicted. Here, the authors find that Trichodesmium growth rates decrease under OA primarily due to reduced nitrogenase efficiency and OA under RCP 8.5 could reduce the N2 fixation potential of Trichodesmium by 27%.

    • Ya-Wei Luo
    • , Dalin Shi
    •  & Futing Zhang
  • Article
    | Open Access

    The current paradigm of material transport across the ocean-floor by gravity currents, is of turbulent flows with mixing processes analogous to rivers. However, uniquely high-resolution field data demonstrate that this paradigm is flawed and that gravity currents are analogous to self-organised atmospheric jets.

    • R. M. Dorrell
    • , J. Peakall
    •  & D. Tezcan
  • Article
    | Open Access

    Coral bleaching is generally linked to higher sea temperatures, but there may be geographic variation in this effect. Here, in a synthesis of global coral bleaching data, the authors show that bleaching probability is highest at mid-latitude sites despite equivalent thermal stress at equatorial sites.

    • S. Sully
    • , D. E. Burkepile
    •  & R. van Woesik
  • Article
    | Open Access

    Lurgi et al. analyse the distribution of microbial symbionts across many sponge species and reveal modules of non-random associations which are primarily driven by host features and microbial phylogenies, and less by the environment. Results also show that metabolic functions are distinct across modules.

    • Miguel Lurgi
    • , Torsten Thomas
    •  & Jose M. Montoya
  • Article
    | Open Access

    Chromatophores in cephalopod skin are known for fast changes in coloration due to light-scattering pigment granules. Here, authors demonstrate structural coloration facilitated by reflectin in sheath cells and offer insights into the interplay between structural and pigmentary coloration elements.

    • Thomas L. Williams
    • , Stephen L. Senft
    •  & Leila F. Deravi
  • Article
    | Open Access

    Active Atlantic hurricane seasons are favoured by positive sea surface temperature anomalies. Here the authors identify a new air-sea heat flux driver for these anomalies in the severe 2017 season, while the recent 2005 and 2010 severe seasons were mainly driven by weakened ocean overturning circulation.

    • Samantha Hallam
    • , Robert Marsh
    •  & Joël J.-M. Hirschi
  • Article
    | Open Access

    Particulate organic carbon (POC) fluxes in the oceans, particularly the Southern Ocean, remain poorly constrained. Here the authors modelled the potential underestimated flux of POC originating from Antarctic krill and discovered a seasonal krill faecal pellet export flux of 0.039 GT C yr-1 across the marginal ice zone (MIZ) of the Southern Ocean.

    • A. Belcher
    • , S. A. Henson
    •  & G. A. Tarling
  • Article
    | Open Access

    The geographical distribution and controlling factors of marine N2 fixation are understudied. Here the authors find increasing rates of N2 fixation from the Sargasso Sea to the coastal waters of North America, driven primarily by cyanobacterial diazotrophs and best correlated with phosphorus availability and chlorophyll-a concentrations.

    • Weiyi Tang
    • , Seaver Wang
    •  & Nicolas Cassar
  • Article
    | Open Access

    Coccolithophores are one of the most abundant phytoplankton and calcifying organisms, well-known to produce intricate calcareous exoskeletons made of coccoliths. Here the authors show, by using X-ray nanotomography, the dependence of the grid size on the calcite nucleation site number and on the mass of coccoliths.

    • T. Beuvier
    • , I. Probert
    •  & A. Gibaud
  • Article
    | Open Access

    Ferromanganese minerals are abundant in marine environments but the extent of these minerals in subseafloor sediments remains unknown. Here the authors find abundant ferromanganese microparticles in oxic pelagic clays, accounting for 14–16% of the new estimate of the global manganese budget (9.2–47.4 Tt).

    • Go-Ichiro Uramoto
    • , Yuki Morono
    •  & Fumio Inagaki
  • Article
    | Open Access

    Changes in chlorophyll-a are used as an indirect proxy for monitoring global changes in marine phytoplankton. Here the authors show that remote sensing reflectance (RRS), such as the ratio of upwelling versus downwelling light at the ocean’s surface, has a stronger and earlier climate-change-driven signal over the 21st century.

    • Stephanie Dutkiewicz
    • , Anna E. Hickman
    •  & Erwan Monier
  • Article
    | Open Access

    The spatio-temporal distributions of these plastics are not fully characterized. Here the authors examined the sources, sinks and pathways and projected microplastic concentrations for 2066 and found that most plastics accumulate in the North Pacific, with the highest concentrations predicted in the East Asia Seas and central North Pacific.

    • Atsuhiko Isobe
    • , Shinsuke Iwasaki
    •  & Tadashi Tokai