News & Views |
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News |
Minnesota bog study turns up the heat on peat
Experiment boosts temperature and carbon dioxide to gauge global-warming response.
- Alexandra Witze
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News & Views |
Uncertain future for vegetation cover
How will Earth's vegetation cover respond to climate change, and how does this compare with changes associated with human land use? Modelling studies reveal how little we still know, and act as a clarion call for further work.
- Almut Arneth
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News & Views |
Cyanate fuels the nitrogen cycle
Cyanate, a degradation product of urea and cyanide, has been found to be a sufficient single substrate for the growth and reciprocal feeding of microorganisms that are essential to the global nitrogen cycle. See Letter p.105
- Lisa Y. Stein
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News & Views |
Iron's voyage from the abyss
An iron-rich plume of water from a hydrothermal vent has been found to extend more than 4,000 kilometres through the ocean. The finding has implications for the productivity of marine algae, and therefore for climate. See Letter p.200
- Kazuhiro Misumi
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News & Views |
Growing feedback from ocean carbon to climate
The finding that feedbacks between the ocean's carbon cycle and climate may become larger than terrestrial carbon–climate feedbacks has implications for the socio-economic effects of today's fossil-fuel emissions.
- Fortunat Joos
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News & Views |
Exclusive networks in the sea
The identification of an exchange of nutrients and signalling molecules between a planktonic alga and a bacterium demonstrates that targeted mutualistic interactions occur across domains of life in the oceans. See Letter p.98
- Alexander J. Limardo
- & Alexandra Z. Worden
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Letter |
Global carbon export from the terrestrial biosphere controlled by erosion
Particulate organic carbon export from the terrestrial biosphere is primarily controlled by physical erosion, and tectonic and climatic forcing of physical erosion may favour biospheric particulate organic carbon sequestration over silicate weathering as a long-term atmospheric carbon dioxide sink.
- Valier Galy
- , Bernhard Peucker-Ehrenbrink
- & Timothy Eglinton
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News |
Fjords soak up a surprising amount of carbon
Inlets at high latitudes store carbon faster than do other marine ecosystems.
- Boer Deng
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News |
Acidic oceans linked to greatest extinction ever
Rocks from 252 million years ago suggest that carbon dioxide from volcanoes made sea water lethal.
- Alexandra Witze
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Review Article |
Climate change and the permafrost carbon feedback
A large amount of organic carbon stored in frozen Arctic soils (permafrost) could be released as carbon dioxide and methane in a warming climate, which would accelerate the pace of climate change; this review suggests that release of greenhouse gas emissions will be gradual but prolonged.
- E. A. G. Schuur
- , A. D. McGuire
- & J. E. Vonk
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News |
Climate modellers take tropical approach
Ten-year US-led project seeks to plug gaps in global-warming simulations.
- Jeff Tollefson
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Research Highlights |
Methane's great Arctic escape
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News & Views |
Signs of saturation in the tropical carbon sink
The carbon sink in the land biosphere has grown during the past 30 years, taking up much of the carbon dioxide produced by human activities. The first signs of this growth levelling off have been spotted in Amazon forests. See Letter p.344
- Lars O. Hedin
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Perspective |
Defining the Anthropocene
Formal criteria must be met to define a new human-driven epoch; the geological evidence appears to do so, with 1610 and 1964 both likely to satisfy the requirements for the start of the Anthropocene.
- Simon L. Lewis
- & Mark A. Maslin
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Letter |
Decrease in CO2 efflux from northern hardwater lakes with increasing atmospheric warming
Atmospheric warming may reduce CO2 emissions from hardwater lakes by reducing the duration of ice cover, increasing lake water pH and favouring CO2 sequestration.
- Kerri Finlay
- , Richard J. Vogt
- & Peter R. Leavitt
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Letter |
Isotopic evidence for biological nitrogen fixation by molybdenum-nitrogenase from 3.2 Gyr
Nitrogen isotope ratios from rocks between 3.2 and 2.75 billion years old are most readily explained by biological nitrogen fixation, most probably using the metal molybdenum as a cofactor, showing that nitrogen fixation is at least 3.2 billion years old and suggesting that molybdenum was available to organisms long before the Great Oxidation Event.
- Eva E. Stüeken
- , Roger Buick
- & Matthew C. Koehler
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Letter |
Agricultural Green Revolution as a driver of increasing atmospheric CO2 seasonal amplitude
The increase in amplitude of the atmospheric carbon dioxide cycle over the past fifty years can be attributed in part to the intensification of agriculture in the Northern Hemisphere.
- Ning Zeng
- , Fang Zhao
- & Luis Guanter
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Article |
Global diets link environmental sustainability and human health
As incomes grow, diets change, with varying impacts on human health and the environment; here the links are examined and suggestions made for diets that both improve health and minimize environmental impacts.
- David Tilman
- & Michael Clark
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Letter |
Methane dynamics regulated by microbial community response to permafrost thaw
The abundance of key microbial lineages can be used to predict atmospherically relevant patterns in methane isotopes and the proportion of carbon metabolized to methane during permafrost thaw, suggesting that microbial ecology may be important in ecosystem-scale responses to global change.
- Carmody K. McCalley
- , Ben J. Woodcroft
- & Scott R. Saleska
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Letter |
Global covariation of carbon turnover times with climate in terrestrial ecosystems
A global, observation-based assessment of whole-ecosystem carbon turnover times shows that the overall mean global carbon turnover time is about 23 years and that locally its spatial variability depends on precipitation at least as strongly as on temperature.
- Nuno Carvalhais
- , Matthias Forkel
- & Markus Reichstein
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Letter |
Placing an upper limit on cryptic marine sulphur cycling
The oxygen isotopic composition of seawater sulphate in oxygen-deficient waters records the degree of in situ sulphur cycling.
- D. T. Johnston
- , B. C. Gill
- & W. Berelson
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Letter |
Temperature sensitivity of soil respiration rates enhanced by microbial community response
Microbial community responses in soils from the Arctic to the Amazon often enhance the longer-term temperature sensitivity of respiration, particularly in soils with high carbon-to-nitrogen ratios and in soils from cold regions, suggesting that carbon stored in Arctic and boreal soils could be more vulnerable to climate warming than currently predicted.
- Kristiina Karhu
- , Marc D. Auffret
- & Iain P. Hartley
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Letter |
Seasonal not annual rainfall determines grassland biomass response to carbon dioxide
Large annual variation in the stimulation of above-ground biomass by elevated carbon dioxide in a mixed C3/C4 temperate grassland can be predicted accurately using seasonal rainfall totals.
- Mark J. Hovenden
- , Paul C. D. Newton
- & Karen E. Wills
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Letter |
Contribution of semi-arid ecosystems to interannual variability of the global carbon cycle
The unusually large land carbon sink reported in 2011 can mostly be attributed to semi-arid vegetation growth in the Southern Hemisphere following increased rainfall and long-term greening trends.
- Benjamin Poulter
- , David Frank
- & Guido R. van der Werf
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Letter |
Trace-gas metabolic versatility of the facultative methanotroph Methylocella silvestris
Distinct groups of microorganisms have been thought to grow on methane and on short-chain alkanes; now, the methanotroph Methylocella silvestris is shown to express two distinct soluble di-iron centre monooxygenases that allow it to use either methane or propane as a carbon and energy source.
- Andrew T. Crombie
- & J. Colin Murrell
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Letter |
Reconciliation of the carbon budget in the ocean’s twilight zone
The discrepancy between the components of the oceanic carbon budget — export of carbon from the surface and its conversion into carbon dioxide by water-column biota at depth — is reconciled using field data and a steady-state model which indicates that synergy between microbes and zooplankton is an important factor.
- Sarah L. C. Giering
- , Richard Sanders
- & Daniel J. Mayor
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Letter |
Methane fluxes show consistent temperature dependence across microbial to ecosystem scales
Meta-analyses show that the temperature dependence of methane fluxes scales consistently across populations of methanogens, microbial communities and whole ecosystems, and that this temperature dependence is higher than for respiration and photosynthesis; this indicates that global warming may impact the relative contributions of CO2 and CH4 to total greenhouse gas emissions.
- Gabriel Yvon-Durocher
- , Andrew P. Allen
- & Paul A. del Giorgio
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Letter |
Amazon forests maintain consistent canopy structure and greenness during the dry season
Lidar and optical satellite observations of Amazon forests indicate consistent canopy structure and reflectance during the dry season, challenging the paradigm of light-limited tropical forest productivity.
- Douglas C. Morton
- , Jyoteshwar Nagol
- & Peter R. J. North
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Letter |
A two-fold increase of carbon cycle sensitivity to tropical temperature variations
The long-term record of atmospheric carbon dioxide growth rate shows that the sensitivity of this growth rate to tropical temperature variability has increased by a factor of about two in the past five decades, and was greater when tropical land regions experienced drier conditions, implying that moisture regulates this sensitivity.
- Xuhui Wang
- , Shilong Piao
- & Anping Chen
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Letter |
Sulphoglycolysis in Escherichia coli K-12 closes a gap in the biogeochemical sulphur cycle
Escherichia coli K-12 performs sulphoglycolysis; heterologous expression of enzymes encoded in a ten-gene cluster present in almost all (>91%) available E. coli genomes is used to show that sulphoquinovose is catabolised through four reactions to produce dihydroxyacetone phosphate, which powers energy conservation and growth, and a sulphonate product, which is excreted.
- Karin Denger
- , Michael Weiss
- & David Schleheck
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Letter |
Rate of tree carbon accumulation increases continuously with tree size
A global analysis shows that for most tree species the largest trees are the fastest-growing trees, a finding that resolves conflicting assumptions about tree growth and that has implications for understanding forest carbon dynamics, resource allocation trade-offs within trees and plant senescence.
- N. L. Stephenson
- , A. J. Das
- & M. A. Zavala
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Letter |
Amazon River carbon dioxide outgassing fuelled by wetlands
Global carbon budgets reveal that inland waters emit substantial amounts of carbon, which is believed to originate from the terrestrial biosphere; however, here the carbon emitted from the Amazon River system is shown to originate from temporary wetlands in the flooded area itself, such as flooded forests.
- Gwenaël Abril
- , Jean-Michel Martinez
- & Fabio Roland
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Article |
Global carbon dioxide emissions from inland waters
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
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Letter |
Decoupling of soil nutrient cycles as a function of aridity in global drylands
Soil samples collected from 224 dryland sites around the world show that aridity affects the concentration of organic carbon and total nitrogen differently from the concentration of inorganic phosphorus, suggesting that any predicted increase in aridity with climate change could uncouple the carbon, nitrogen and phosphorus cycles in drylands and negatively affect the services provided by these ecosystems.
- Manuel Delgado-Baquerizo
- , Fernando T. Maestre
- & Eli Zaady
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Letter |
Atmospheric oxygenation three billion years ago
The distribution of chromium isotopes and redox-sensitive metals in the Nsuze palaeosol and in the Ijzermyn iron formation from the Pongola Supergroup, in South Africa, suggests that there were appreciable levels of atmospheric oxygen about three billion years ago, some 300–400 million years earlier than previous indications for Earth surface oxygenation.
- Sean A. Crowe
- , Lasse N. Døssing
- & Donald E. Canfield
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Letter |
Key role of symbiotic dinitrogen fixation in tropical forest secondary succession
In tropical moist forests, nitrogen-fixing tree species can supply a large proportion of the nitrogen required for net forest growth in the first 12 years of recovery after human or natural perturbation, with nitrogen-fixing trees accumulating carbon up to nine times faster per individual than non-fixing trees, and species-specific differences in the amount and timing of fixation.
- Sarah A. Batterman
- , Lars O. Hedin
- & Jefferson S. Hall
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Letter |
Asymmetric effects of daytime and night-time warming on Northern Hemisphere vegetation
Correlations between the maximum and minimum daily temperatures and a vegetation index in the Northern Hemisphere suggest that asymmetric diurnal warming (faster warming of the land surface during the night than during the day) produces several different vegetation and carbon storage effects.
- Shushi Peng
- , Shilong Piao
- & Hui Zeng
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Perspective |
Climate extremes and the carbon cycle
The effects of climate extremes such as droughts or storms on the carbon cycle of ecosystems are investigated; such extremes can decrease regional carbon stocks.
- Markus Reichstein
- , Michael Bahn
- & Martin Wattenbach
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Letter |
Nitrogen losses in anoxic marine sediments driven by Thioploca–anammox bacterial consortia
A novel symbiotic consortium is described between two chemolithotrophic bacteria — anaerobic ammonium-oxidizing (anammox) bacteria and the nitrate-sequestering sulphur-oxidizing Thioploca species — in anoxic sediments of the Soledad basin at the Mexican Pacific margin.
- M. G. Prokopenko
- , M. B. Hirst
- & D. M. Sigman
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Letter |
Allowable carbon emissions lowered by multiple climate targets
The amount of greenhouse gas emissions that will limit the risks from such emissions has been set by the goal of keeping global warming below two degrees Celsius above preindustrial, but this study sets thresholds for sea level rise, ocean acidification and agricultural productivity as well as warming and shows that emissions need to be lowered even further.
- Marco Steinacher
- , Fortunat Joos
- & Thomas F. Stocker
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Letter |
Barium distributions in teeth reveal early-life dietary transitions in primates
The patterning of barium in tooth enamel is shown to be a reliable marker of lactation in humans and macaques; furthermore, the study of a tooth from a Neanderthal child reveals the weaning process in this extinct species.
- Christine Austin
- , Tanya M. Smith
- & Manish Arora
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Letter |
Long-term warming restructures Arctic tundra without changing net soil carbon storage
Two decades of summer warming in an Alaskan tundra ecosystem increased plant biomass and woody dominance, indirectly increased winter soil temperature, homogenized the soil trophic structure and suppressed surface-soil-decomposer activity, but did not change net soil carbon or nitrogen storage.
- Seeta A. Sistla
- , John C. Moore
- & Joshua P. Schimel
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Letter |
Changes in global nitrogen cycling during the Holocene epoch
A global synthesis of stable nitrogen isotopic values in lacustrine sediments indicates a period of declining enrichment from 15,000 to 7,000 years before present, probably in response to terrestrial carbon sequestration.
- Kendra K. McLauchlan
- , Joseph J. Williams
- & Elizabeth S. Jeffers
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Letter |
Sensitivity of tropical carbon to climate change constrained by carbon dioxide variability
A linear relationship between the sensitivity of tropical land carbon storage to warming and the sensitivity of the annual growth rate of atmospheric CO2 to tropical temperature anomalies provides a tight constraint on the sensitivity of tropical land carbon to climate change.
- Peter M. Cox
- , David Pearson
- & Catherine M. Luke
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Letter |
Deep instability of deforested tropical peatlands revealed by fluvial organic carbon fluxes
Riverine carbon-14 measurements show that anthropogenic disturbance of peat swamp forest in southeast Asia is causing increased release of carbon that has been stored in the peat for thousands of years.
- Sam Moore
- , Chris D. Evans
- & Vincent Gauci
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Letter |
Sustainable bioenergy production from marginal lands in the US Midwest
A comparative assessment of six alternative cropping systems over 20 years shows that, once well established, successional herbaceous vegetation grown on marginal lands has a direct greenhouse gas emissions mitigation capacity that rivals that of purpose-grown crops.
- Ilya Gelfand
- , Ritvik Sahajpal
- & G. Philip Robertson
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Research Highlights |
Rain shifts bear human fingerprint
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Letter |
Flickering gives early warning signals of a critical transition to a eutrophic lake state
Critical transitions in experimental and theoretical systems can be anticipated on the basis of specific warning signs, with ‘critical slowing down’ being the best studied; long-term data from a real system, a Chinese lake, now show that a flickering phenomenon can be observed up to 20 years before the critical transition to a eutrophic state.
- Rong Wang
- , John A. Dearing
- & Marten Scheffer
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News & Views |
A piece of the methane puzzle
The identification of a sea-floor microorganism that single-handedly conducts anaerobic oxidation of methane changes our picture of how the flux of this greenhouse gas from the ocean to the atmosphere is regulated. See Article p.541
- Samantha B. Joye