Environmental chemistry

  • Article |

    Preliminary modelling of airborne microplastics suggests that they may be exerting a minor cooling influence on the present-day atmosphere, and continued production could have increasing effects on the climate system in future.

    • Laura E. Revell
    • , Peter Kuma
    •  & Sally Gaw
  • Article |

    Mercury deposition pathways from the atmosphere to the ocean remain uncertain, but mercury stable isotope measurements from the Atlantic and Mediterranean show that ocean uptake of gaseous elemental mercury is more important than previously thought.

    • Martin Jiskra
    • , Lars-Eric Heimbürger-Boavida
    •  & Jeroen E. Sonke
  • Article
    | Open Access

    Geospatial variation in the micronutrient composition (calcium, iron, selenium and zinc) of staple cereal grains is nutritionally important at subnational scales in Ethiopia and Malawi; these data could be used to improve surveillance of micronutrient deficiencies in the region.

    • D. Gashu
    • , P. C. Nalivata
    •  & M. R. Broadley
  • Article |

    Observations and air-quality modelling reveal that the sources of particulate matter and oxidative potential in Europe are different, implying that reducing mass concentrations of particulate matter alone may not reduce oxidative potential.

    • Kaspar R. Daellenbach
    • , Gaëlle Uzu
    •  & André S. H. Prévôt
  • Article |

    Isotopic evidence from ice cores indicates that preindustrial-era geological methane emissions were lower than previously thought, suggesting that present-day emissions of methane from fossil fuels are underestimated.

    • Benjamin Hmiel
    • , V. V. Petrenko
    •  & E. Dlugokencky
  • Article |

    This analysis of the exchange of air pollution amongst the contiguous United States finds that, on average, around half of the early deaths caused by a state’s air pollution occurs outside that state, with different contributions by different emission sectors and chemical species.

    • Irene C. Dedoussi
    • , Sebastian D. Eastham
    •  & Steven R. H. Barrett
  • 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
  • Article |

    Adding reactive gases such as isoprene to mixtures lowers the production of secondary organic aerosol in the atmosphere, thus reducing the atmospheric particulate burden, with implications for human health and climate.

    • Gordon McFiggans
    • , Thomas F. Mentel
    •  & Astrid Kiendler-Scharr
  • 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 |

    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
  • Letter |

    The evaporation and atmospheric oxidation of low-volatility organic vapours from mined oil sands material is shown to be responsible for a large amount of secondary organic aerosol mass—which affects air quality and climate change—observed during airborne measurements in Canada.

    • John Liggio
    • , Shao-Meng Li
    •  & Drew R. Gentner
  • Letter
    | Open Access

    The growth of nucleated organic particles has been investigated in controlled laboratory experiments under atmospheric conditions; initial growth is driven by organic vapours of extremely low volatility, and accelerated by more abundant vapours of slightly higher volatility, leading to markedly different modelled concentrations of atmospheric cloud condensation nuclei when this growth mechanism is taken into account.

    • Jasmin Tröstl
    • , Wayne K. Chuang
    •  & Urs Baltensperger
  • Letter |

    Aircraft measurements, laboratory photolysis experiments and modelling calculations reveal a mechanism for the recycling of nitric acid into nitrogen oxides; this enables observations to be reconciled with model studies, and suggests that particulate nitrate photolysis could be a substantial tropospheric nitrogen oxide source.

    • Chunxiang Ye
    • , Xianliang Zhou
    •  & Christoph Knote
  • Letter |

    The net balance of terrestrial biogenic greenhouse gases produced as a result of human activities and the climatic impact of this balance are uncertain; here the net cumulative impact of the three greenhouse gases, methane, nitrous oxide and carbon dioxide, on the planetary energy budget from 2001 to 2010 is a warming of the planet.

    • Hanqin Tian
    • , Chaoqun Lu
    •  & Steven C. Wofsy
  • Letter |

    Data from the long-running Park Grass Experiment is used to show that grassland biodiversity is recovering since UK atmospheric nitrogen levels started to decline 25 years ago in all but the most acidic soils.

    • J. Storkey
    • , A. J. Macdonald
    •  & M. J. Crawley
  • Perspective |

    Instead of containing stable and chemically unique ‘humic substances’, as has been widely accepted, soil organic matter is a mixture of progressively decomposing organic compounds; this has broad implications for soil science and its applications.

    • Johannes Lehmann
    •  & Markus Kleber
  • Letter |

    Measurements of sediments eroded by the Mackenzie River reveal the widespread export of permafrost-derived biospheric carbon that is several thousand years old, and demonstrate its burial in the Arctic Ocean, suggesting that high-latitude rivers can act as important carbon dioxide sinks.

    • Robert G. Hilton
    • , Valier Galy
    •  & Damien Calmels
  • Letter |

    Hydrothermal dissolved iron, manganese, and aluminium from the southern East Pacific Rise is transported several thousand kilometres westward across the South Pacific Ocean; global hydrothermal dissolved iron input is estimated to be more than four times what was previously thought and modelling suggests it must be physically or chemically stabilized in solution.

    • Joseph A. Resing
    • , Peter N. Sedwick
    •  & Alessandro Tagliabue
  • Letter |

    A multi-omics approach, integrating metagenomics, metatranscriptomics and metaproteomics, determines the phylogenetic composition of the microbial community and assesses its functional potential and activity along a thaw transition from intact permafrost to thermokast bog.

    • Jenni Hultman
    • , Mark P. Waldrop
    •  & Janet K. Jansson
  • Letter |

    Data from the oil- and gas-producing basin of northeastern Utah and a box model are used to assess the photochemical reactions of nitrogen oxides and volatile organic compounds that lead to excessive atmospheric ozone pollution in winter.

    • Peter M. Edwards
    • , Steven S. Brown
    •  & Robert Zamora
  • Letter |

    Observations of methyl chloroform combined with an atmospheric transport model predict a Northern to Southern Hemisphere hydroxyl ratio of slightly less than 1, whereas commonly used atmospheric chemistry models predict ratios 15–45% higher.

    • P. K. Patra
    • , M. C. Krol
    •  & D. Young
  • Letter |

    GEOTRACES sampling of deep water from the Atlantic, Pacific and Southern oceans allows an estimate of the amount (tripled in surface waters) and distribution (two-thirds increase in water less than a thousand metres deep) of anthropogenic mercury accumulating in the global ocean.

    • Carl H. Lamborg
    • , Chad R. Hammerschmidt
    •  & Mak A. Saito
  • Letter |

    A high-resolution oceanic section of dissolved iron stable isotope ratios reveals that the primary source of dissolved iron to the North Atlantic is atmospheric dust, while seafloor sediments and submarine volcanic vents also contribute significantly.

    • Tim M. Conway
    •  & Seth G. John
  • Letter |

    Sulphide oxidation coupled to carbonate dissolution can provide a transient source of carbon dioxide to Earth’s atmosphere and so balance the Cenozoic increase in carbon dioxide consumption by silicate weathering, reconciling this increase with the need for mass balance in the long-term carbon cycle.

    • Mark A. Torres
    • , A. Joshua West
    •  & Gaojun Li
  • Letter |

    The link between biogenic volatile organic compounds in the atmosphere and their conversion to aerosol particles is unclear, but a direct reaction pathway is now described by which volatile organic compounds lead to low-volatility vapours that can then condense onto aerosol surfaces, producing secondary organic aerosol.

    • Mikael Ehn
    • , Joel A. Thornton
    •  & Thomas F. Mentel
  • Brief Communications Arising |

    • Scott Jasechko
    • , Zachary D. Sharp
    •  & Peter J. Fawcett
  • Article |

    An analysis of regional variations in global inland water surface area, dissolved CO2 and gas transfer velocity yields a global CO2 evasion rate of 2.1 × 1015 grams of carbon per year, which is higher than previous estimates owing to a larger contribution from streams and rivers.

    • Peter A. Raymond
    • , Jens Hartmann
    •  & Peter Guth
  • Letter |

    Until now, dimethylsulphoniopropionate (DMSP), an important component in the sulphur cycle, has been thought to be produced solely by algae and some plants; however, this study shows that the coral animal also produces DMSP, in addition to that produced by the coral’s algal symbiont, with potential implications for the sulphur cycle and its climatic consequences as corals and their symbionts are affected by global change.

    • Jean-Baptiste Raina
    • , Dianne M. Tapiolas
    •  & Cherie A. Motti
  • Letter |

    Holocene aquifers are the source of much arsenic poisoning in south and southeast Asia, whereas Pleistocene aquifers are mostly safe; here the delayed arsenic contamination of a Pleistocene aquifer is described and modelled.

    • Alexander van Geen
    • , Benjamín C. Bostick
    •  & Michael Berg
  • Letter |

    Data on bulk nitrogen deposition, plant foliar nitrogen and crop nitrogen uptake in China between ad 1980 and ad 2010 show that the average annual bulk deposition of nitrogen increased by approximately 8 kilograms of nitrogen per hectare during that period and that nitrogen deposition rates in the industrialized and agriculturally intensified regions of China are as high as the peak levels of deposition in northwestern Europe in the 1980s.

    • Xuejun Liu
    • , Ying Zhang
    •  & Fusuo Zhang
  • Article |

    Methane oxidation under anaerobic conditions coupled to sulphate reduction is thought to be carried out by a consortium of methanotrophic archaea (ANME) and sulphate-reducing Deltaproteobacteria; here it is shown that ANME alone can mediate the reaction and that the associated bacteria perform disulphide disproportionation, a new microbial sulphur transformation.

    • Jana Milucka
    • , Timothy G. Ferdelman
    •  & Marcel M. M. Kuypers