Ocean sciences

  • Article |

    An underlying assumption of palaeoceanographic proxies is that they are representative of the water properties directly above their site of deposition. Here, the authors combine high-resolution particle tracking simulations and sedimentary proxy data to challenge this assumption.

    • Erik van Sebille
    • , Paolo Scussolini
    •  & Rainer Zahn
  • Article |

    Extreme sea level rises are a threat to coastal communities, but their cause, in terms of seasonal or interannual time scales, has received little attention. Here, the authors combine observational and model data to show that one such rise in 2009–10 was caused by a 30% downturn in the Atlantic overturning circulation.

    • Paul B. Goddard
    • , Jianjun Yin
    •  & Shaoqing Zhang
  • Article |

    The microbial carbon pump may play an important role in carbon sequestration in the deep ocean, but quantifying organic matter in this dark realm is difficult. Here, the authors use fluorescence spectroscopy to investigate the turnover time of fluorescent dissolved organic matter.

    • Teresa S. Catalá
    • , Isabel Reche
    •  & X. Antón Álvarez-Salgado
  • Article |

    Marine sedimentary 231Pa/230Th ratios are considered a promising tool for the investigation of past modes of ocean circulation. Here, the authors present a compilation of new and existing Atlantic sedimentary 231Pa/230Th ratios and interpret these data in the context of abrupt cooling during Heinrich Stadial 1.

    • Louisa I. Bradtmiller
    • , Jerry F. McManus
    •  & Laura F. Robinson
  • Article |

    Reconstructing past sea ice coverage in the Arctic is important for future climate predictions. Here, the authors present a new sea ice record from the Eurasian sector of the Arctic Ocean and report that Arctic sea ice reached its modern winter maximum for the first time 2.6 million years ago.

    • Jochen Knies
    • , Patricia Cabedo-Sanz
    •  & Antoni Rosell-Melé
  • Article
    | Open Access

    Submarine mud volcanoes are difficult to observe from the sea surface and previous recordings at depth have been short term. Here, the authors provide the first long-term monitoring from Håkon Mosby and suggest that mud volcanoes may be more important to the global methane budget than previously thought.

    • Tomas Feseker
    • , Antje Boetius
    •  & Dirk de Beer
  • Article |

    The Antarctic ice sheets contribution to rising sea levels at the end of the last ice age remains a matter of debate. Here, the authors present a suite of ice-sheet modelling experiments and conclude that the retreating Antarctic ice sheet may have contributed as much as 0.7 m per century to meltwater pulse 1A.

    • N. R. Golledge
    • , L. Menviel
    •  & R. H. Levy
  • Article |

    Detailed sea-level records beyond ~150,000 years ago are limited. Here, the authors present a radiometrically constrained sea-level record from the Red Sea, spanning five glacial cycles and examine sea-level rise rates and the effects of past global ice-volume changes on monsoon intensity.

    • K. M. Grant
    • , E. J. Rohling
    •  & F. Williams
  • Article
    | Open Access

    The Great Barrier Reef (GBR) is under threat from rising ocean temperatures, yet its response to past temperature change is poorly known. Felis et al. show that the GBR experienced a much steeper temperature gradient during the last deglaciation, suggesting it may be more resilient than previously thought.

    • Thomas Felis
    • , Helen V. McGregor
    •  & Jody M. Webster
  • Article
    | Open Access

    The Late Cretaceous experienced significant cooling, yet a lack of low-latitude records mean the regional extent of this cooling is poorly constrained. Linnert et al. present a TEX86sea surface temperature record from a palaeolatitude of ~35 °N and show that Late Cretaceous cooling was global in nature.

    • Christian Linnert
    • , Stuart A. Robinson
    •  & Ernest E. Russell
  • Article
    | Open Access

    Arctic sea ice has been in rapid decline in recent decades, yet the impact on biogeochemical cycling is unknown due to insufficient sampling. Watanabe et al.combine year-long mooring observations with numerical models to show that an eddy-induced biological pump would be enhanced by sea ice retreat.

    • Eiji Watanabe
    • , Jonaotaro Onodera
    •  & Michio J. Kishi
  • Article
    | Open Access

    Seagrass beds are effective blue-carbon sinks, yet their role as a lime mud source in the tropical carbonate factory is less well known. Here, the authors demonstrate that the species Thalassia testudinumcan significantly contribute to carbonate production via the precipitation of aragonite needles.

    • Susana Enríquez
    •  & Nadine Schubert
  • Article
    | Open Access

    Glacial meltwaters may help fertilize the iron-limited Polar Oceans, yet the contribution is poorly constrained. Hawkings et al.monitor iron fluxes during a full-melt season in Greenland, and propose that ice sheets provide highly reactive and potentially bioavailable iron, comparable with aeolian dust fluxes.

    • Jon R. Hawkings
    • , Jemma L. Wadham
    •  & Jon Telling
  • Article
    | Open Access

    Whether all rapid climate events during the last ice age impacted the global carbon cycle is not clearly understood. Ahn and Brook present a high-resolution record of atmospheric CO2 from Antarctica and suggest that only Greenland stadials associated with massive iceberg discharge influenced atmospheric CO2.

    • Jinho Ahn
    •  & Edward J. Brook
  • Article
    | Open Access

    Pumice rafts result from volcanic eruptions into and onto water, and can be extensive and potentially hazardous, but tracking their dispersal is difficult. Jutzeler et al.combine satellite imagery and an ocean model to accurately forecast pumice raft dispersal routes.

    • Martin Jutzeler
    • , Robert Marsh
    •  & Leif Karlstrom
  • Article
    | Open Access

    Global sea levels are rising as a result of climate change, but at what rate, and whether this rate is increasing is open to debate. Haigh et al.show that the earliest detection of significant increase in the rate of sea level rise can only be achieved once interannual and multidecadal variability is removed.

    • Ivan D. Haigh
    • , Thomas Wahl
    •  & Sönke Dangendorf
  • Article
    | Open Access

    El Niño Southern Oscillation has a strong impact on current strength and ocean temperatures off the western Australian coast, but long-term variability is poorly understood. Zinke et al.show a strong link between La Niña and El Niño events and decadal Leeuwin current variability in coral records since 1795.

    • J. Zinke
    • , A. Rountrey
    •  & M.T. McCulloch
  • Article
    | Open Access

    The Atlantic Multidecadal Oscillation strongly influences Northern Hemisphere climate, yet its primary driver is poorly understood. Knudsen et al.analyse proxy records from the past ~450 years and show that external forcing has dominated control of the oscillation since the termination of the Little Ice Age.

    • Mads Faurschou Knudsen
    • , Bo Holm Jacobsen
    •  & Jesper Olsen
  • Article |

    Modelling studies suggest that oceanic mesoscale eddies play an important role in the global transport of heat and salt, yet there are few direct observations. Dong et al.present a method to calculate eddy transport through the use of satellite data and Argo profiles and confirm model-based estimates.

    • Changming Dong
    • , James C. McWilliams
    •  & Dake Chen
  • Article |

    Totten Glacier discharges the largest volume of ice in East Antarctica, but the mechanisms causing its recent thinning are relatively unknown. Khazendar et al.combine remote-sensing data with high-resolution ice–ocean modelling to link this recent thinning to reduced sea ice production in polynyas.

    • A. Khazendar
    • , M.P. Schodlok
    •  & M.R. van den Broeke
  • Article |

    The El Niño-Southern Oscillation is one of the largest sources of global climate variability, yet our understanding relative to the Topical Pacific mean state is poor. Here, geochemical analyses of marine plankton reveal a strong link between zonal sea-surface temperatures and ENSO variability.

    • Aleksey Yu Sadekov
    • , Raja Ganeshram
    •  & Alexander W. Tudhope
  • Article
    | Open Access

    The dissolution of iron from sediments along ocean margins may stimulate photosynthesis and moderate global climate. This study shows how margin sediments supply iron in varying amounts between regions, and by distinct mechanisms, which may be due to geological characteristics and hydrological controls on land.

    • William B. Homoky
    • , Seth G. John
    •  & Rachel A. Mills
  • Article |

    Patchiness in the distribution of phytoplankton promotes many of the ecological interactions that underpin the marine food web. This study shows that turbulence, ubiquitous in the ocean, counter-intuitively ‘unmixes’ a population of motile phytoplankton, generating intense, small-scale patchiness in its distribution.

    • William M. Durham
    • , Eric Climent
    •  & Roman Stocker
  • Article |

    Iron plays a key role in controlling biological production in the Southern Ocean, yet mechanisms regulating iron availability are not completely understood. Here, Ingall et al.show that structural incorporation of reduced, organic iron into biogenic silica represents a new and substantial removal pathway.

    • Ellery D. Ingall
    • , Julia M. Diaz
    •  & Jay A. Brandes
  • Article
    | Open Access

    The abrupt ending of the Younger Dryas cooling episode marked the onset of the present interglacial and was the most prominent climate change in the Earth’s recent history. This study shows evidence for a sequence of events with a leading role of the ocean at the transition into the present day warm Holocene epoch.

    • Christof Pearce
    • , Marit-Solveig Seidenkrantz
    •  & Søren M. Kristiansen
  • Article
    | Open Access

    The branched inflow of warm Atlantic Water to the Arctic has been known for more than a hundred years, yet what controls the relative strengths of the two pathways remains poorly understood. Here, the authors identify the role of atmospheric circulation over the northern Barents Sea in controlling inflow.

    • Vidar S. Lien
    • , Frode B. Vikebø
    •  & Øystein Skagseth
  • Article
    | Open Access

    Active seafloor spreading has been documented in some of the tectonically active basins of the Gulf of California. This work presents new geophysical and geochemical data as evidence that active seafloor spreading is also occurring in the northernmost Wagner and Consag basins of the Gulf.

    • Rosa Ma Prol-Ledesma
    • , Marco-Antonio Torres-Vera
    •  & Carlos Robinson
  • Article
    | Open Access

    Palaeoclimate proxies, such as shells, record past ocean changes. A radiocarbon study based on a shell chronology from the Icelandic shelf is used to track changes in ocean circulation and climate for the past 1,350 years, suggesting a declining influence of North Atlantic surface waters on the Icelandic shelf over the last millennium.

    • Alan D. Wanamaker Jr
    • , Paul G. Butler
    •  & Christopher A. Richardson
  • Article |

    Small-scale ocean dynamics can have wide reaching impacts on the larger-scale ocean circulation. Using temperature and velocity data, this study shows the presence of abyssal vortices in the Eastern Mediterranean basin, adding complexity to the structure and evolution of water masses in this region.

    • A. Rubino
    • , F. Falcini
    •  & A. Capone
  • Article
    | Open Access

    The calving of the Mertz Glacier occurred in 2010 in East Antarctica, brought on by the re-positioning of a large iceberg. Using satellite data, this study shows a reduction in sea ice production following the calving, interpreted as a potential regime shift towards reduced sea ice production for the coming decades.

    • T. Tamura
    • , G.D. Williams
    •  & K.I. Ohshima
  • Article
    | Open Access

    Ocean circulation moves heat and gases between the ocean and atmosphere, impacting the carbon cycle at decadal timescales. Here, a radiocarbon coral record of ocean mixing from Bermuda suggests that the formation of mode water, and thus carbon uptake, have been more stable over the past 200 years than previously thought.

    • Nathalie F. Goodkin
    • , Ellen R. M. Druffel
    •  & Scott C. Doney
  • Article |

    Many organisms are responding to a warming climate by shifts in spatial distribution. The poleward movement of silver hake,Merluccius bilinearis, over the last forty years is related to the position of the Gulf Stream and Atlantic meridional overturning circulation through changes in local bottom water temperature.

    • Janet A. Nye
    • , Terrence M. Joyce
    •  & Jason S. Link
  • Article |

    Storm water runoff and wastewater effluent are discharged into oceans, but the full ecological effects of these discharges are unknown. Here, the authors examine the population structure of a marine organism, the bat star, and show that these discharges alter the genetic structure and larval dispersal of this species.

    • Jonathan B. Puritz
    •  & Robert J. Toonen
  • Article |

    Ocean acidification due to increasing carbon dioxide levels can affect the growth and viability of corals. In this study, the authors measured extension, calcification and density in Florida corals collected in 1996, and show that recent climate change did not cause a decline in their extension or calcification.

    • Kevin P. Helmle
    • , Richard E. Dodge
    •  & C. Mark Eakin
  • Article
    | Open Access

    The origin of the Atlantic Multidecadal Oscillation, a semi-periodic variability of sea-surface temperature, is unknown. Knudsenet al.show that 55- to 70-year climate oscillations existed throughout the last 8,000 years, suggesting that the Atlantic Multidecadal Oscillation is a permanent feature of the Holocene climate induced by internal ocean variability.

    • Mads Faurschou Knudsen
    • , Marit-Solveig Seidenkrantz
    •  & Antoon Kuijpers
  • Article |

    Antarctic bottom water is important for the global climate system, but its main source in East Antarctica was altered recently because of calving of the Mertz Glacier Tongue. The authors model this event and find large changes in dense water exports from the region.

    • Kazuya Kusahara
    • , Hiroyasu Hasumi
    •  & Guy D. Williams
  • Article |

    Ocean tides and infragravity waves—the Earths 'hum'—have very different periods and wavelengths. Sugioka and colleagues report resonance between these two phenomena using arrays of broadband ocean-bottom seismometers and show that some tidal energy is transferred to the deep oceans through this coupling.

    • Hiroko Sugioka
    • , Yoshio Fukao
    •  & Toshihiko Kanazawa