Ocean sciences

  • Article
    | Open Access

    Hydrothermal vents are biogeochemically important, but their contribution to the carbon cycle is poorly constrained. Here the authors build a biogeochemical model that estimates autotrophic and heterotrophic production rates of microbial communities within hydrothermal plumes along mid-ocean ridges.

    • Cécile Cathalot
    • , Erwan G. Roussel
    •  & Pierre-Marie Sarradin
  • Article
    | Open Access

    Species identity and richness both contribute biodiversity-ecosystem functioning relationships. Here the authors apply a decomposition approach inspired by the Price equation to a global dataset of reef fish community biomass, finding that increased richness and community compositions favouring large-bodied species enhance biomass.

    • Jonathan S. Lefcheck
    • , Graham J. Edgar
    •  & Aneil F. Agrawal
  • Article
    | Open Access

    The role of Southern Ocean gateways contributing to the Eocene-Oligocene climate transition is still debated. Here, the authors present high-resolution ocean simulations to show that gateways opening led to a reorganization of ocean circulation, heat transport and Antarctic surface water cooling.

    • Isabel Sauermilch
    • , Joanne M. Whittaker
    •  & Joseph H. LaCasce
  • Article
    | Open Access

    Satellite-derived chlorophyll data and Google Earth Engine (GEE) are used to introduce the first global map of coastal eutrophication potential as a GEE app. The prospects of the app being used as a global framework for eutrophication screening/monitoring are discussed.

    • Elígio de Raús Maúre
    • , Genki Terauchi
    •  & Michael DeWitt
  • Article
    | Open Access

    New climate models show a stronger warming with greenhouse gas emissions than is suggested by observations. Here, the authors argue that internal variability of the Atlantic Ocean may have dampened some of the recent warming, which could explain part of the disagreement between the newer models and observations.

    • Rémy Bonnet
    • , Didier Swingedouw
    •  & Adriana Sima
  • Article
    | Open Access

    The Atlantic Niño is an important mode of tropical Atlantic variability that influences the climate conditions in surrounding areas. Here, the authors use observational data and model simulations to show that positive phases of the Indian Ocean Dipole can trigger Atlantic Niño events.

    • Lei Zhang
    •  & Weiqing Han
  • Article
    | Open Access

    As corals struggle to survive under climate change, it is crucial to know whether they can withstand increasing seawater temperatures. Using a controlled thermal stress experiment across three divergent coral holobionts, this study examines metatranscriptomic responses to heat stress corresponding to the coral host, photosymbionts and associated microbiota.

    • Viridiana Avila-Magaña
    • , Bishoy Kamel
    •  & Mónica Medina
  • Article
    | Open Access

    In ultraslow-spreading ridges intermittent detachment faulting could contribute to discontinuous magmatic accretion supporting the development of massive sulfide deposits. Here the authors using a multi-scale magnetic survey of the Southwest Indian Ridge constrain that an episode of detachment faulting took place 0.7-1.48 Ma, with the present fault active since 0.33 Ma.

    • Tao Wu
    • , Maurice A. Tivey
    •  & Yunlong Liu
  • Article
    | Open Access

    Sea spray aerosol (SSA) are an important way through which oceans can influence the atmosphere’s radiative properties. Here, the authors present measurements taken over a 42,000 km ship cruise in the Atlantic and Pacific Ocean and show that SSA number concentrations vary over a 24-hour cycle, possibly linked to surface water bubble-bursting dynamics.

    • J. Michel Flores
    • , Guillaume Bourdin
    •  & Ilan Koren
  • Article
    | Open Access

    Modelling and sea surface temperature proxy data from the Weddell Sea document a 3–4 °C drop coinciding with the Early Cretaceous Weissert Event. Temperature data worldwide confirm a 3.0 °C global mean surface cooling, equivalent to a ~40% drop in atmospheric pCO2, favouring local polar ice.

    • Liyenne Cavalheiro
    • , Thomas Wagner
    •  & Elisabetta Erba
  • Article
    | Open Access

    Phytoplankton form the base of the marine ecosystem but current ocean models used for climate change projections are too simple to assess potential changes in plankton community structure. This study analyses a complex ecosystem model with 35 phytoplankton types to evaluate the changes in phytoplankton community composition, turnover and size structure over the 21st century.

    • Stephanie A. Henson
    • , B. B. Cael
    •  & Stephanie Dutkiewicz
  • Article
    | Open Access

    Warming will affect marine plankton biomass, but also its diversity and community composition in poorly understood ways. Here, the authors model the spatial distribution of 860 marine plankton species from 10 functional groups and identify the future hotspots of climate change impacts under RCP8.5.

    • Fabio Benedetti
    • , Meike Vogt
    •  & Nicolas Gruber
  • Article
    | Open Access

    The motion of the ocean transports microorganisms, pollutants, and other particles, but these are challenging to track. Here the authors present a Lagrangian form of Betweenness Centrality which identifies bottlenecks in dynamical systems and fluid flows as well as an interpretation of diversity hotspots.

    • Enrico Ser-Giacomi
    • , Alberto Baudena
    •  & Emilio Hernández-García
  • Article
    | Open Access

    Over the past century, the Western Antarctic Peninsula has experienced rapid warming and a substantial loss of sea ice with important implications for plankton biodiversity and carbon cycling. Using a 5-year DNA metabarcoding dataset, this study assesses how interannual variability in sea-ice conditions impacts biodiversity and biological carbon fluxes in this region.

    • Yajuan Lin
    • , Carly Moreno
    •  & Nicolas Cassar
  • Article
    | Open Access

    Marine heat waves and cold spells threaten ocean ecosystems and are thought to be increasing with climate change. Here the author shows that MHW/MCS in the Tasman Sea co-occur with corresponding events in the Atlantic, Indian, and Pacific Oceans, and these southern hemisphere events are driven by stalling of a global wavenumber-4 atmospheric wave.

    • Stephen M. Chiswell
  • Article
    | Open Access

    Silica formation in diatoms is of interest for a range of different subjects from biomimetics to oceanography. Here the authors study the formation of silicified extensions in diatoms and find that unlike cell wall elements, that form in the cytoplasm, the extensions have a different formation mechanism outside the cytoplasm.

    • Boaz Mayzel
    • , Lior Aram
    •  & Assaf Gal
  • Article
    | Open Access

    How acute deoxygenation events affect tropical marine ecosystems remains poorly understood. This study integrates analyses of coral reef benthic communities with microbial community sequencing to show how a deoxygenation event rapidly altered a shallow tropical coral reef ecosystem in the Caribbean.

    • Maggie D. Johnson
    • , Jarrod J. Scott
    •  & Andrew H. Altieri
  • Article
    | Open Access

    The deep North Pacific is the end of the road for global ocean circulation, but the circulation patterns and ventilation are poorly understood. Here the authors show that diffusive transports both along and across density layers play a leading role in returning 1,400 year old water to the surface.

    • Mark Holzer
    • , Tim DeVries
    •  & Casimir de Lavergne
  • Article
    | Open Access

    Nitrogen fixation by diazotrophs is critical for marine primary production. Using Tara Oceans datasets, this study combines a quantitative image analysis pipeline with metagenomic mining to provide an improved global overview of diazotroph abundance, diversity and distribution.

    • Juan José Pierella Karlusich
    • , Eric Pelletier
    •  & Rachel A. Foster
  • Article
    | Open Access

    Estimating velocities in gas liquid flows is of importance in many engineering applications. Hohermuth et al. show that previous bubble velocities obtained from intrusive probes have been underestimated and provide a correction scheme for more accurate velocity measurements.

    • B. Hohermuth
    • , M. Kramer
    •  & D. Valero
  • Article
    | Open Access

    N2 fixation by heterotrophic bacteria has recently been found to take place on sinking marine particles, but an understanding of its regulation and importance is lacking. Here the authors develop a trait-based model for this N2 fixation, finding that this once overlooked process could have global importance.

    • Subhendu Chakraborty
    • , Ken H. Andersen
    •  & Lasse Riemann
  • Article
    | Open Access

    How sea-level in the western Mediterranean reacts to climate changes is not well known. Here, the authors present a regional reconstruction and show that temperatures influenced sea-level change rates during the Holocene, while recent sea-level rise is happening faster than during any other period of the last 4000 years.

    • Matteo Vacchi
    • , Kristen M. Joyse
    •  & Alessio Rovere
  • Article
    | Open Access

    Reprocessed data from satellite altimetry show that the mean significant wave height decreases globally by 22% on average from 30 km to 3 km from the coast. By combining these data with wave period from reanalysis, we estimate a mean reduction of 38% concerning the mean wave energy flux.

    • Marcello Passaro
    • , Mark A. Hemer
    •  & Florian Seitz
  • Article
    | Open Access

    As sea levels rise, coasts are being increasingly  threatened by overtopping caused by the combination of sea level rise, storm surge and wave runup. Here the authors find that global coastal overtopping has increased by over 50% in the last two decades, and under a RCP 8.5 scenario this could increase up to 50 times by 2100 compared to today.

    • Rafael Almar
    • , Roshanka Ranasinghe
    •  & Elodie Kestenare
  • Article
    | Open Access

    North Atlantic deep water (NADW) formation influences the climate and carbon cycle, but the contribution of Arctic waters is difficult to constrain. Here the authors use Pa/Th proxy measurements to determine the amount of Arctic Ocean water that flows through the Fram Strait and contributes to NADW.

    • Lauren E. Kipp
    • , Jerry F. McManus
    •  & Markus Kienast
  • Article
    | Open Access

    Primary productivity in the oligotrophic ocean sustains Earth’s ecosystems, but nutrient concentrations are vanishingly low. Here the authors measure nanomolar macronutrient concentrations in the North Pacific and find that net community production is sustained through high rates of phosphorus recycling.

    • Fuminori Hashihama
    • , Ichiro Yasuda
    •  & Masao Ishii
  • Article
    | Open Access

    The middle of the Gulf of Mexico is stratified and highly oligotrophic, yet there are anomalously high fluxes of sinking particulate matter from the euphotic zone. Here the authors show that lateral advection of organic matter supports nitrogen export in the Gulf of Mexico’s open ocean.

    • Thomas B. Kelly
    • , Angela N. Knapp
    •  & Michael R. Stukel
  • Article
    | Open Access

    Up to 40% of the ocean’s fixed nitrogen is lost in oxygen minimum zones (OMZs) by anammox, but despite the importance of this process, nitrogen loss patterns in OMZs are difficult to predict. Here the authors show that ammonium release from small particles is a major control of anammox in the Peruvian OMZ.

    • Clarissa Karthäuser
    • , Soeren Ahmerkamp
    •  & Marcel M. M. Kuypers
  • Article
    | Open Access

    The macroalgae Sargassum has grown for centuries in the oligotrophic North Atlantic supported by natural nutrient sources and cycling. Here the authors show that changes in tissue nutrient contents since the 1980s reflect global anthropogenic nitrogen enrichment, causing blooms in the wider Atlantic basin.

    • B. E. Lapointe
    • , R. A. Brewton
    •  & P. L. Morton
  • Article
    | Open Access

    A large fraction of ice sheet discharge enters the ocean subsurface from underneath large floating ice-tongues. Here the authors show that associated nutrient export may be governed by shelf circulation and, especially for Fe, particle-dissolved phase exchanges, which is largely independent from freshwater Fe content.

    • Stephan Krisch
    • , Mark James Hopwood
    •  & Eric Pieter Achterberg
  • Article
    | Open Access

    New data from five hot-water drilled boreholes show how atmospheric anomalies affect the circulation beneath Filchner-Ronne Ice Shelf on multi-year time scales. The apparent link of the dense water formation to remote teleconnections is an important step for better predicting contributions to future sea level rise from this sector of Antarctica.

    • Tore Hattermann
    • , Keith W. Nicholls
    •  & Torsten Kanzow
  • Article
    | Open Access

    The Arctic Ocean cooling machine, currently the Barents Sea, plays a crucial role in both regulating the climate and determining the deep ocean circulation. Here the authors show that the efficiency of the cooling machine is poleward enhanced in a warming climate, which pushes Arctic Atlantification poleward.

    • Qi Shu
    • , Qiang Wang
    •  & Fangli Qiao
  • Article
    | Open Access

    Marine snow is a major route through which photosynthetically fixed carbon is transported to the deep ocean, but the factors affecting flux are largely unknown. Here the authors use high frequency imaging of marine snow particles collected during phytoplankton blooms to categorize and quantify transport.

    • Emilia Trudnowska
    • , Léo Lacour
    •  & Lars Stemmann
  • Article
    | Open Access

    The COVID-19 response has led to unparalleled changes in the functioning of human society, from travel restrictions to changes in consumption. Here the authors use high resolution satellite data to track the global reduction in marine traffic during the pandemic, and more recent hints of recovery to pre-lockdown levels.

    • David March
    • , Kristian Metcalfe
    •  & Brendan J. Godley
  • Article
    | Open Access

    Warming ocean water plays a significant role in accelerating Arctic sea ice melt. Here the authors present detailed observations of warm water of Pacific origin entering and diving beneath the Arctic ocean surface, and explore the dynamical processes governing its evolution.

    • Jennifer A. MacKinnon
    • , Harper L. Simmons
    •  & Kevin R. Wood
  • Article
    | Open Access

    Microplastic pollution is a major threat to marine food webs, but the wider ranging impacts on global ocean biogeochemistry are poorly understood. Here the authors use an Earth system model to determine that zooplankton grazing on microplastics could exacerbate trends in ocean oxygen loss.

    • K. Kvale
    • , A. E. F. Prowe
    •  & A. Oschlies
  • Article
    | Open Access

    Ocean warming and changing circulation as a result of climate change are driving down oxygen levels and threatening ecosystems. Here the author shows that though immediate cessation of anthropogenic CO2 emissions would halt upper ocean oxygen loss, it would continue in the deep ocean for 100 s of years.

    • Andreas Oschlies
  • Article
    | Open Access

    Extracting functional information from 16S rRNA data surveys would provide a valuable tool for large-scale functional ecology. Here, the authors use PICRUSt2 to infer metabolic functions from bacterial marker gene data across the South Pacific Ocean, and compare them with rate data, biomass estimators and predictions based on shotgun metagenomes.

    • Eric J. Raes
    • , Kristen Karsh
    •  & Anya M. Waite
  • Article
    | Open Access

    New simulations find that one of Antarctica’s largest ice shelves, the Filchner–Ronne, may be less vulnerable to climate change than previously thought. Melting of the ice shelf initially decreases for many decades, and only increases when global warming exceeds approximately 7 °C.

    • Kaitlin A. Naughten
    • , Jan De Rydt
    •  & Jeff K. Ridley
  • Article
    | Open Access

    Sea-level rise is an important part of climate change, but most sea-level budgets are global and cannot capture important regional changes. Here the authors estimate sea-level budgets along the U.S. Atlantic coast, finding a faster rate of rise during the 20th century than any time in the past 2000 years.

    • Jennifer S. Walker
    • , Robert E. Kopp
    •  & Benjamin P. Horton