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| Open AccessThermal sensitivity of field metabolic rate predicts differential futures for bluefin tuna juveniles across the Atlantic Ocean
In this study, the authors use a dataset of stable isotope compositions of otoliths from Atlantic bluefin tuna to infer the thermal sensitivity of metabolic performance in their first year of life. They then assess the likely trajectories of tuna production until end century under differing emission scenarios in their two main spawning grounds, the western Atlantic and Mediterranean Sea.
- Clive N. Trueman
- , Iraide Artetxe-Arrate
- & Igaratza Fraile
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Article
| Open AccessMicrobial growth under drought is confined to distinct taxa and modified by potential future climate conditions
Climate change increases the frequency and intensity of drought events, affecting soil functions driven by microorganisms. Here, Metze et al. develop a method to estimate microbial growth rates in dry soils, and provide insights into the response of active microbes to drought today and in potential future climate conditions (high temperatures and CO2 levels).
- Dennis Metze
- , Jörg Schnecker
- & Andreas Richter
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| Open AccessSingle-cell isotope tracing reveals functional guilds of bacteria associated with the diatom Phaeodactylum tricornutum
Bacterial remineralization of algal organic matter promotes algal growth but is rarely quantified. Here, Mayali et al. quantify bacterial incorporation of algal-derived organic carbon and nitrogen, and algal incorporation of remineralized carbon and nitrogen, for 15 bacterial co-cultures growing with the diatom Phaeodactylum tricornutum to identify functional guilds of metabolic interactions.
- Xavier Mayali
- , Ty J. Samo
- & Peter K. Weber
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Article
| Open AccessThe origin of suspended particulate matter in the Great Barrier Reef
This multidisciplinary fingerprinting study, using isotopic, structural and genetic fingerprints, has shown that the suspended particulate matter in the Great Barrier Reef does not have terrestrial origin but produced locally by marine phytoplankton
- Mohammad Bahadori
- , Chengrong Chen
- & Tom Stevens
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Article
| Open AccessHydrogen and dark oxygen drive microbial productivity in diverse groundwater ecosystems
Microbes in ancient groundwaters can be very diverse and productive. Some microbes seem to produce oxygen in the dark, which others use to consume the greenhouse gas methane. Their metabolisms are relevant for groundwater health and global change.
- S. Emil Ruff
- , Pauline Humez
- & Marc Strous
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Article
| Open AccessPrehistoric population expansion in Central Asia promoted by the Altai Holocene Climatic Optimum
The impact of climate change on Holocene human activity in the Altai-Sayan region of Central Asia is unclear. Here, the authors use pollen, biogenic silica, and isotope records from lake cores to show that the climate prompted human population expansion and intensified cultural exchange during the Bronze Age.
- Lixiong Xiang
- , Xiaozhong Huang
- & Fahu Chen
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Article
| Open AccessIntracellular carbon storage by microorganisms is an overlooked pathway of biomass growth
Microbes are often assumed to reproduce as much as possible, but it has now been shown that soil microbes actually store a large part of their carbon intake. This could help microbial communities withstand environmental changes.
- Kyle Mason-Jones
- , Andreas Breidenbach
- & Michaela A. Dippold
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| Open AccessContrasting geochemical and fungal controls on decomposition of lignin and soil carbon at continental scale
Lignin’s contribution to soil organic carbon (SOC) is contentious. The authors find a decoupling of lignin and SOC decomposition and their contrasting relationships with geochemical and microbial factors, addressing a long-standing controversy.
- Wenjuan Huang
- , Wenjuan Yu
- & Steven J. Hall
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Article
| Open AccessElevated temperature and CO2 strongly affect the growth strategies of soil bacteria
Microbial ecological strategies are expected to be phylogenetically conserved, but plasticity and acclimation to environmental change may complicate the picture. Here, the authors show that shifts in soil bacterial ecological strategies deviate from phylogenetic-based predictions after acclimation to long-term warming and CO2 enrichment.
- Yang Ruan
- , Yakov Kuzyakov
- & Ning Ling
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Article
| Open AccessIntensive grassland management disrupts below-ground multi-trophic resource transfer in response to drought
Land use intensification could make soil food webs less able to recover from drought. Here, the authors find that intensive grassland management impairs recent photosynthate flux to roots and soil biota after drought, whereas extensive grassland management buffers the legacy of drought.
- Mathilde Chomel
- , Jocelyn M. Lavallee
- & Richard D. Bardgett
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Article
| Open AccessWarming and redistribution of nitrogen inputs drive an increase in terrestrial nitrous oxide emission factor
Soil nitrogen isotopic composition is used to drive the IsoTONE model, which is constrained with measurements of tropospheric nitrous oxide isotopic composition. The model results reveal causes of rising mean global nitrous oxide emission factor.
- E. Harris
- , L. Yu
- & P. Rayner
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Article
| Open AccessGiant sponge grounds of Central Arctic seamounts are associated with extinct seep life
This study reports the discovery of dense sponge gardens across the peaks of permanently ice-covered, extinct volcanic seamounts of the Langseth Ridge and on the remnants of a now extinct seep ecosystem. Using approaches to sample and infer food and energy sources to this ice-covered community, the authors suggest that the sponges use refractory organic matter trapped in the extinct seep community on which they sit.
- T. M. Morganti
- , B. M. Slaby
- & A. Boetius
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| Open AccessImpact of intensifying nitrogen limitation on ocean net primary production is fingerprinted by nitrogen isotopes
Projected declines in marine primary production are underpinned by a slowdown in nitrogen supplied to surface waters. Here the authors detail a new means to detect this slowdown and describe major shifts in the 21st century oceanic nitrogen cycle.
- Pearse J. Buchanan
- , Olivier Aumont
- & Alessandro Tagliabue
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Article
| Open AccessMethane from microbial hydrogenolysis of sediment organic matter before the Great Oxidation Event
Microbial CH4 kept the early Earth warm under the faint young sun, but clear records are lacking. Here the authors present isotopic evidence that CH4 seepage in the Canadian shield is from hydrogen biodegradation in a Neoarchean ecosystem rather than an abiotic synthesis product.
- Xinyu Xia
- & Yongli Gao
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| Open AccessPurple sulfur bacteria fix N2 via molybdenum-nitrogenase in a low molybdenum Proterozoic ocean analogue
N2 fixation was key to the expansion of life on Earth, but which organisms fixed N2 and if Mo-nitrogenase was functional in the low Mo early ocean is unknown. Here, the authors show that purple sulfur bacteria fix N2 using Mo-nitrogenase in a Proterozoic ocean analogue, despite low Mo conditions.
- Miriam Philippi
- , Katharina Kitzinger
- & Marcel M. M. Kuypers
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Article
| Open AccessParticulate organic matter as a functional soil component for persistent soil organic carbon
The fate of soil carbon is controlled by plant inputs, microbial activity, and the soil matrix. Here the authors extend the notion of plant-derived particulate organic matter, from an easily available and labile carbon substrate, to a functional component at which persistence of soil carbon is determined.
- Kristina Witzgall
- , Alix Vidal
- & Carsten W. Mueller
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Article
| Open AccessImportant contributions of non-fossil fuel nitrogen oxides emissions
This study investigates in the importance of non-fossil fuel NOx emissions in the surface-earth-nitrogen cycle. The study shows how changes of regional human activities directly influence δ15N signatures of deposited NOx to terrestrial environments and that emissions have largely been underestimated.
- Wei Song
- , Xue-Yan Liu
- & Cong-Qiang Liu
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Article
| Open AccessAerobic microbial life persists in oxic marine sediment as old as 101.5 million years
The discovery of aerobic microbial communities in nutrient-poor sediments below the seafloor begs the question of the mechanisms for their persistence. Here the authors investigate subseafloor sediment in the South Pacific Gyre abyssal plain, showing that aerobic microbial life can be revived and retain metabolic potential even from 101.5 Ma-old sediment.
- Yuki Morono
- , Motoo Ito
- & Fumio Inagaki
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| Open AccessCalcium isotopic ecology of Turkana Basin hominins
Non-traditional stable isotopes, such as of calcium, have potential to expand our understanding of ancient diets. Here, Martin et al. use stable calcium isotopes recovered from fossil tooth enamel to compare the dietary ecology of hominins and other primates in the Turkana Basin 2-4 million years ago.
- Jeremy E. Martin
- , Théo Tacail
- & Vincent Balter
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Article
| Open AccessMarine resource abundance drove pre-agricultural population increase in Stone Age Scandinavia
How the development of human societies is influenced through their ecological environment and climatic conditions has been the subject of intensive debate. Here, the authors present multi-proxy data from southern Scandinavia which suggests that pre-agricultural population growth there was likely influenced by enhanced marine production.
- J. P. Lewis
- , D. B. Ryves
- & S. Juggins
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| Open AccessArchaeal lipid biomarker constraints on the Paleocene-Eocene carbon isotope excursion
The Paleocene-Eocene Thermal Maximum (c. 55 million years ago) was a period associated with massive carbon injection into the atmosphere, yet discrepancies in carbon isotope proxy records have led to substantial uncertainties in the source, scale, and timing of carbon emissions. Here, the authors propose that membrane lipids of marine planktonic archaea can reliably record the carbon isotope excursion and surface ocean warming, giving a new constraint for the source and size of the PETM carbon emissions.
- Felix J. Elling
- , Julia Gottschalk
- & Ann Pearson
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| Open AccessRevisiting enteric methane emissions from domestic ruminants and their δ13CCH4 source signature
Global average, geographical distribution and temporal variations of the 13C isotopic signature of enteric fermentation emissions are not well understood. Here the authors established a global dataset and show a larger emission increase between the two periods (2002–2006 and 2008–2012) than previous studies.
- Jinfeng Chang
- , Shushi Peng
- & Philippe Bousquet
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Article
| Open AccessCoral carbon isotope sensitivity to growth rate and water depth with paleo-sea level implications
Rising anthropogenic CO2 levels in the atmosphere are resulting in ocean acidification which may impact coral growth rates. Here, the authors quantify the relationship between water depth and δ13C compositions of South Pacific corals from the pre-industrial era, and their results should lead to improvements in the precision of sea level reconstructions using fossil corals.
- Braddock K. Linsley
- , Robert B. Dunbar
- & Gerard M. Wellington
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| Open AccessEvolutionary history biases inferences of ecology and environment from δ13C but not δ18O values
The effects of biological similarity on geochemical signals recorded in planktonic foraminiferal tests used in paleo-reconstructions remains unclear. Here, the authors embed species-specific vital effect offsets in evolutionary models and show how shared evolutionary history shapes δ13C, but not δ18O values.
- Kirsty M. Edgar
- , Pincelli M. Hull
- & Thomas H. G. Ezard
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Article
| Open AccessTree height strongly affects estimates of water-use efficiency responses to climate and CO2 using isotopes
Intrinsic water-use efficiency (W i ) reconstructions using tree rings often disregard developmental changes in W i as trees age. Here, the authors compare W i across varying tree sizes at a fixed CO2 level and show that ignoring developmental changes impacts conclusions on trees’ W i responses to CO2 or climate.
- R. J. W. Brienen
- , E. Gloor
- & M. Timonen
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| Open AccessAncient and methane-derived carbon subsidizes contemporary food webs
Alluvial aquifers of river floodplains support abundant large-bodied consumers despite an absence of light and scarcity of organic carbon. DelVecchia et al. reveal that much of the biomass carbon in these freshwater consumers is ancient and derived from methane.
- Amanda G. DelVecchia
- , Jack A. Stanford
- & Xiaomei Xu
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Article
| Open AccessA dual-isotope approach to allow conclusive partitioning between three sources
Stable isotopes are a useful tool for distinguishing two sources in a mixture, but frequently systems have more than two components. Here, the authors propose a new approach to allow conclusive partitioning between three sources, still using only two stable isotopes, looking at soil CO2emissions.
- Thea Whitman
- & Johannes Lehmann
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Article |
Trends and oscillations in the Indian summer monsoon rainfall over the last two millennia
Summertime rainfall over South Asia has declined in the last few decades, possibly due to human aerosols. Here, the authors present a record of Indian monsoon rainfall over the last two millennial and suggest that large natural variability may mask any forced changes in monsoon.
- Ashish Sinha
- , Gayatri Kathayat
- & R. L. Edwards
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| Open AccessOsmium isotope evidence for a large Late Triassic impact event
Before the mass extinction that characterized the Late Triassic period, there were a series of biotic turnover events, the cause of which are the subject of debate. Sato et al. present geochemical evidence in support of the theory that extraterrestrial impacts had an important role in these events.
- Honami Sato
- , Tetsuji Onoue
- & Katsuhiko Suzuki