Biogeochemistry

  • Article
    | Open Access

    Our understanding of microbial diversity and physiology in marine sediments is limited. Here, Gong et al. analyze thousands of metagenome-assembled genomes (MAGs) from coastal and deep-sea sediments, and identify MAGs belonging to new bacterial phyla that seem able to mediate key steps in sedimentary biogeochemistry.

    • Xianzhe Gong
    • , Álvaro Rodríguez del Río
    •  & Brett J. Baker
  • Article
    | Open Access

    Geochemical data from sedimentary rocks in Siberia indicate that members of the soft-bodied Ediacara biota (the earliest macroscopic life on Earth) were tolerant of low-oxygen conditions, suggesting they had the capacity for anaerobic metabolisms.

    • Lucas B. Cherry
    • , Geoffrey J. Gilleaudeau
    •  & Alan J. Kaufman
  • Article
    | Open Access

    The burial of organic carbon in marine sediments regulates Earth’s carbon cycle and climate. Here, authors present ‘transfer efficiencies’ as a new framework for quantifying the sedimentary portion of the marine organic carbon cycle.

    • James A. Bradley
    • , Dominik Hülse
    •  & Sandra Arndt
  • Article
    | Open Access

    A California stalagmite records vegetation shifts and increased fire activity during the 8.2 kyr event. These changes occur alongside oscillations between wet and dry extremes suggesting tight coupling between climate whiplash and fire activity.

    • Julia Homann
    • , Jessica L. Oster
    •  & Thorsten Hoffmann
  • Article
    | Open Access

    How reduced seawater pH and increased carbon dioxide might affect the prominent nitrogen fixer Trichodesmium in phosphorus-limited oceans is poorly understood. This study used phosphate-limited chemostat experiments to show that Trichodesmium may fix less nitrogen for a given amount of phosphorus at low pH. Thus, marine productivity is likely to decline in a future, more acidic ocean.

    • Futing Zhang
    • , Zuozhu Wen
    •  & Dalin Shi
  • Article
    | Open Access

    The mechanisms underlying methane production in oxygenated waters of oceans and lakes are unclear. Here, Perez-Coronel and Beman show that aerobic methane production in freshwater incubation experiments is associated with (bacterio)chlorophyll metabolism and photosynthesis, and with Proteobacterial degradation of methylphosphonate.

    • Elisabet Perez-Coronel
    •  & J. Michael Beman
  • Article
    | Open Access

    A climate sensitive permafrost region (Yedoma domain) was found to contain globally relevant N stock of >40 Gt nitrogen, of which 4 to 16 Gt of the N could become available by thaw until 2100. This study increases the current estimates by nearly 50%.

    • Jens Strauss
    • , Christina Biasi
    •  & Guido Grosse
  • Article
    | Open Access

    This synthesis of carbon isotope data in circum-Arctic shelf sediments provides a holistic, receptor-based perspective of how carbon release and transport vary between Arctic soils, peat and permafrost deposits amongst the different Arctic regions.

    • Jannik Martens
    • , Birgit Wild
    •  & Örjan Gustafsson
  • Article
    | Open Access

    Distinguishing biotic compounds from abiotic ones is critical to the search for life in the universe. Here, the authors demonstrate that the abiotic ethane has distinctively low 13C-13C abundances compared to biotic ethane.

    • Koudai Taguchi
    • , Alexis Gilbert
    •  & Yuichiro Ueno
  • Article
    | Open Access

    The northern high latitude permafrost region has been an important contributor to the carbon sink since the 1980s. A new study finds that as tree cover increases, respiratory CO2 loss during late-growing season offsets photosynthetic CO2 uptake and leads to a slower rate of increasing annual net CO2 uptake.

    • Zhihua Liu
    • , John S. Kimball
    •  & Naveen Chandra
  • Article
    | Open Access

    Plant respiration at night is assumed to be temperature-controlled. Here, the authors show that temperature controls less than half of the variation in leaf respiration rate at night, and demonstrate how to account for such nocturnal variation in biosphere models.

    • Dan Bruhn
    • , Freya Newman
    •  & Lina M. Mercado
  • Article
    | Open Access

    Accurate estimates of carbon fluxes are important to our understanding of the carbon cycle. Here, via model-data integration, the authors disentangle anthropogenic and environmental carbon flux contributions of terrestrial woody vegetation, and find that environmental processes are weaker and more susceptible to interannual variations and extreme events in the 21st century than previously estimated.

    • Selma Bultan
    • , Julia E. M. S. Nabel
    •  & Julia Pongratz
  • Article
    | Open Access

    Astrochronology of a core in Maryland suggests that the onset of the Paleocene-Eocene Thermal Maximum (PETM) warming lasted about 6 thousand years. These data are more consistent with astronomical forcing than an extraterrestial trigger for the PETM.

    • Mingsong Li
    • , Timothy J. Bralower
    •  & Marci M. Robinson
  • Article
    | Open Access

    The response of soil organic carbon to climate warming may be soil depth-dependent, but remains unquantified in situ. Here the authors show that warming induces more proportional soil carbon losses in topsoil than in subsoil, particularly from high-latitudinal carbon-rich soils.

    • Mingming Wang
    • , Xiaowei Guo
    •  & Zhongkui Luo
  • Article
    | Open Access

    Summary for general audience: We used carbon stable isotope data from an Antarctic ice core to evaluate which mechanisms caused changes in atmospheric carbon dioxide 74-59 thousand years ago, including a ~40 ppm decrease at the beginning of the last ice age.

    • James A. Menking
    • , Sarah A. Shackleton
    •  & Vasilii V. Petrenko
  • Article
    | Open Access

    The impact of land-use and cover-change (LUCC) on ecosystem carbon stock in China is poorly known due to large biases in existing databases. Here the authors develop a new LUCC database with corrected false signals and reveal that forest expansion is the dominant driver of China’s recent carbon sink.

    • Zhen Yu
    • , Philippe Ciais
    •  & Guoyi Zhou
  • Article
    | Open Access

    Using paired reconstructions of seawater pCO2, temperature, and nutrient utilization, Dai et al. show underappreciated influences of the solubility pump on deglacial Subantarctic surface-water pCO2 variabilities compared to the biological pump.

    • Yuhao Dai
    • , Jimin Yu
    •  & Xuan Ji
  • Article
    | Open Access

    Phosphate is critical for all life on Earth but its origins have remained enigmatic. Experiments indicate that phosphate may have been abundant in ancient Fe-rich seawater, providing a crucial ingredient for the origins of life on Earth.

    • Matthew P. Brady
    • , Rosalie Tostevin
    •  & Nicholas J. Tosca
  • Article
    | Open Access

    Phosphorus (P) limitation is pervasive in tropical forests. Here the authors analyse the dependence of photosynthesis on leaf N and P in tropical forests, and show that incorporating leaf P constraints in a terrestrial biosphere model enhances its predictive power.

    • David S. Ellsworth
    • , Kristine Y. Crous
    •  & Ian J. Wright
  • Article
    | Open Access

    Arctic warming thaws permafrost, leading to enhanced soil mercury transport to the Arctic Ocean. Mercury isotope signatures in arctic rivers, ocean and atmosphere suggest that permafrost mercury is buried in marine sediment and not emitted to the global atmosphere

    • Beatriz Ferreira Araujo
    • , Stefan Osterwalder
    •  & Jeroen E. Sonke
  • Article
    | Open Access

    Biomass allocation in plants is fundamental for understanding and predicting terrestrial carbon storage. Here, the authors conduct a meta-analysis showing that warming effect on plant root:shoot is influenced by precipitation and the type of mycorrhizal fungi associated.

    • Lingyan Zhou
    • , Xuhui Zhou
    •  & Madhav P. Thakur
  • Article
    | Open Access

    Our understanding of ancient organic carbon cycling in marine environments is limited. Here the authors developed a method to reconstruct upper ocean organic carbon chemistry in the geological past, which when applied, can help to create a better understanding of the evolution of the carbon cycle.

    • Babette A. A. Hoogakker
    • , Caroline Anderson
    •  & Victoria L. Peck
  • Article
    | Open Access

    Compound extreme events in two or more oceanic ecosystem stressors are increasingly considered as a major concern for marine life. Here the authors present a first global analysis on compound marine heatwave and ocean acidity extreme events, identifying hotspots, drivers, and projecting future changes.

    • Friedrich A. Burger
    • , Jens Terhaar
    •  & Thomas L. Frölicher
  • Article
    | Open Access

    Researchers at Newcastle University have discovered a mechanism by which earthquakes create bursts of hydrogen peroxide and oxygen in hot underground fractures. These may have played a vital role in the early evolution and origin of life on Earth.

    • Jordan Stone
    • , John O. Edgar
    •  & Jon Telling
  • Article
    | Open Access

    Climatic variables have played a significant role in plant evolution across the Phanerozoic. Here, the authors link climate with a new dynamic vegetation model to identify two windows of opportunity for plant biomass expansion, corresponding with the expansion of land plants and the angiosperm radiation.

    • Khushboo Gurung
    • , Katie J. Field
    •  & Benjamin J. W. Mills
  • Article
    | Open Access

    Ultra-high resolution mass spectrometry revealed that plastic bags leach labile compounds. Bioassays performed in Scandinavian lakes indicated that these compounds are incorporated into biomass faster and more efficiently than natural organic matter.

    • Eleanor A. Sheridan
    • , Jérémy A. Fonvielle
    •  & Andrew J. Tanentzap
  • Article
    | Open Access

    Soil microbial carbon is central to soil functions and services, but its spatial-temporal dynamics are unclear. Here the authors show global trends in soil microbial carbon, which suggests a global decrease in soil microbial carbon, mostly driven by temperature increases in northern areas.

    • Guillaume Patoine
    • , Nico Eisenhauer
    •  & Carlos A. Guerra
  • Article
    | Open Access

    Tropical forest lake sediments are global carbon sinks, representing an important implication for climate change, of which both temperature and forest conservation are key factors in maintaining the carbon burial mechanism in lacustrine ecosystems.

    • Leonardo Amora-Nogueira
    • , Christian J. Sanders
    •  & Humberto Marotta
  • Article
    | Open Access

    Dissolved carbon concentrations in the ocean interior are computed by a deep-learning model using ocean surface data. In the Southern Ocean, they decreased in the 1990s-2000s and increased since 2010, reducing anthropogenic carbon uptake potential.

    • Varvara E. Zemskova
    • , Tai-Long He
    •  & Nicolas Grisouard
  • Article
    | Open Access

    Water availability is a major control of vegetation dynamics and terrestrial carbon cycling. Here, the authors show that vegetation sensitivity to soil moisture has been increasing in the last 36 years, especially in (semi)arid areas, and that state-of-the-art land surface models fail to capture this trend.

    • Wantong Li
    • , Mirco Migliavacca
    •  & Rene Orth
  • Article
    | Open Access

    The roles of marine plastisphere in global nitrogen cycling are largely unknown. Here, the authors indicate that the plastisphere could act as a potential source of N2O production, which is mainly regulated by the biotic denitrification

    • Xiaoxuan Su
    • , Leyang Yang
    •  & Yong-guan Zhu
  • Article
    | Open Access

    Mineral-organic associations play a key role in soil carbon preservation. Here, Georgiou et al. produce global estimates of mineral-associated soil carbon, providing insight into the world’s soils and their capacity to store carbon

    • Katerina Georgiou
    • , Robert B. Jackson
    •  & Margaret S. Torn
  • Article
    | Open Access

    The effects of fertiliser from intensive agriculture are well recognised, but not so well for fine-sediment. Here we show how widespread ingress of agriculturally derived fine-sediment since the 1940s markedly amplifies methane emissions from streams.

    • Yizhu Zhu
    • , J. Iwan Jones
    •  & Mark Trimmer