Element cycles

  • Article |

    Structural, functional and localization studies reveal that Geobacter sulfurreducens pili cannot behave as microbial nanowires, instead functioning in a similar way to secretion pseudopili to export cytochrome nanowires that are essential for extracellular electron transfer.

    • Yangqi Gu
    • , Vishok Srikanth
    •  & Nikhil S. Malvankar
  • Article |

    Sulfur isotope and iron–sulfur–carbon systematics on marine sediments indicate that permanent atmospheric oxygenation occurred around 2.22 billion years ago, about 100 million years later than currently estimated.

    • Simon W. Poulton
    • , Andrey Bekker
    •  & David T. Johnston
  • Article
    | Open Access

    Candidatus Azoamicus ciliaticola’ transfers energy to its ciliate host in the form of ATP and enables this host to breathe nitrate, demonstrating that eukaryotes with remnant mitochondria can secondarily acquire energy-providing endosymbionts.

    • Jon S. Graf
    • , Sina Schorn
    •  & Jana Milucka
  • Article |

    Bottom-up and top-down approaches are used to quantify global nitrous oxide sources and sinks resulting from both natural and anthropogenic sources, revealing a 30% increase in global human-induced emissions between 1980 and 2016.

    • Hanqin Tian
    • , Rongting Xu
    •  & Yuanzhi Yao
  • Article |

    A co-culture of two newly identified microorganisms—‘Candidatus Manganitrophus noduliformans’ and Ramlibacter lithotrophicus—exhibits exponential growth that is dependent on manganese(II) oxidation, demonstrating the viability of this metabolism for supporting life.

    • Hang Yu
    •  & Jared R. Leadbetter
  • Article |

    Analyses of microbial communities that live 10–750 m below the seafloor at Atlantis Bank, Indian Ocean, provide insights into how these microorganisms survive by coupling energy sources to organic and inorganic carbon resources.

    • Jiangtao Li
    • , Paraskevi Mara
    •  & Virginia P. Edgcomb
  • Article |

    Anoxygenic photosynthetic microorganisms can biomineralize manganese oxides without molecular oxygen being present and without high-potential photosynthetic reaction centres, which sheds doubt on proposed dates for the origins of oxygenic photosynthetic metabolism.

    • Mirna Daye
    • , Vanja Klepac-Ceraj
    •  & Tanja Bosak
  • Letter |

    Overfishing and warming ocean temperature have caused an increase in methylmercury concentrations in some Atlantic predatory fish, and this trend is predicted to continue unless stronger mercury and carbon emissions standards are imposed.

    • Amina T. Schartup
    • , Colin P. Thackray
    •  & Elsie M. Sunderland
  • Letter |

    Estimates of spatial patterns of nitrogen discharge into water bodies across China between 1955 and 2014 show that current discharge rates are almost three times the acceptable threshold, and ways to restore a clean water environment are suggested.

    • ChaoQing Yu
    • , Xiao Huang
    •  & James Taylor
  • Article |

    Convergent estimates of nitrogen fixation from an inverse biogeochemical and a prognostic ocean model show that biological carbon export in the ocean is higher than expected and that stabilizing nitrogen-cycle feedbacks are weaker than we thought.

    • Wei-Lei Wang
    • , J. Keith Moore
    •  & François W. Primeau
  • Letter |

    Satellite observations reveal over 200 ammonia hotspots associated with agricultural and industrial point sources, which emit much larger quantities of ammonia to the atmosphere than previously thought.

    • Martin Van Damme
    • , Lieven Clarisse
    •  & Pierre-François Coheur
  • Letter |

    Triple oxygen isotope measurements of 1.4-billion-year-old sedimentary sulfates reveal a unique mid-Proterozoic atmosphere and demonstrate that gross primary productivity in the mid-Proterozoic was between 6% and 41% of pre-anthropogenic levels.

    • Peter W. Crockford
    • , Justin A. Hayles
    •  & Boswell A. Wing
  • Letter |

    Phytotransferrin, a functional analogue of transferrin, has an obligate requirement for carbonate to bind iron, which suggests that acidification-driven declines in the concentration of seawater carbonate ions may negatively affect diatom iron acquisition.

    • Jeffrey B. McQuaid
    • , Adam B. Kustka
    •  & Andrew E. Allen
  • Letter |

    Nutrient amendment experiments at the boundary of the South Atlantic gyre reveal extensive regions in which nitrogen and iron are co-limiting, with other micronutrients also approaching co-deficiency; such limitations potentially increase phytoplankton community diversity.

    • Thomas J. Browning
    • , Eric P. Achterberg
    •  & C. Mark Moore
  • Letter |

    Steroid biomarkers provide evidence for a rapid rise of marine planktonic algae between 659 and 645 million years ago, establishing more efficient energy transfers and driving ecosystems towards larger and increasingly complex organisms.

    • Jochen J. Brocks
    • , Amber J. M. Jarrett
    •  & Tharika Liyanage
  • Letter |

    Examination of the ecosystem properties of treeline ecotones in seven temperate regions of the world shows that the reduction in temperature with increasing elevation does not affect tree leaf nutrient concentrations, but does reduce ground-layer community-weighted plant nitrogen levels, leading to a strong stoichiometric convergence of ground-layer plant community nitrogen to phosphorus ratios across all regions.

    • Jordan R. Mayor
    • , Nathan J. Sanders
    •  & David A. Wardle
  • Letter |

    Low phosphorus burial in shallow marine sedimentary rocks before about 750 million years ago implies a change in the global phosphorus cycle, coinciding with the end of what may have been a stable low-oxygen world.

    • Christopher T. Reinhard
    • , Noah J. Planavsky
    •  & Kurt O. Konhauser
  • Letter |

    There is an abrupt transition from alkaline to acid soil pH when mean annual precipitation exceeds mean annual potential evapotranspiration, demonstrating that climate creates a nonlinear pattern in soil solution chemistry at the global scale.

    • E. W. Slessarev
    • , Y. Lin
    •  & O. A. Chadwick
  • Article |

    Bacteria of the SAR11 clade constitute up to one half of all marine microbes and are thought to require oxygen for growth; here, a subgroup of SAR11 bacteria are shown to thrive in ocean oxygen minimum zones and to encode abundant respiratory nitrate reductases.

    • Despina Tsementzi
    • , Jieying Wu
    •  & Frank J. Stewart