To our knowledge, this study represents the first application of 13C-metabolic flux analysis to a human fungal pathogen, where we identified carbon reservoirs and quantified the metabolic fluxes of pa...

These results confirm that, under soil acidification, less photosynthetic C in roots was converted into rhizodeposit C entering the soil, while proportionally more was invested in root growth, respir....

Vascular epiphytes exhibit a minimal but noteworthy leaf–root 15N fractionation compared with soil-rooted plants, reflecting the more severe N stress in the canopy habitats. The leaf–root 15N fractio...

Rationale Stable isotopes can be useful for tracking diet composition and other physiological processes in ruminants. These techniques rely on the fact that tissues directly reflect the animal's die...

Building soil organic carbon (SOC) is critical for agroecosystem functioning and resilience to climate change. SOC storage is driven by the accumulati…

Information on the trophic ecology of top predators such as cetaceans is critical for understanding their role in ecosystem structure. Furthermore, po…

Tracer-aided mixing models are uniquely capable of identifying water flow paths and sources within the Critical Zone Recent advances offer novel tracers and models for deeper and more accurate in...

Understanding trophic relationships is fundamental for investigating ecosystem processes and their role in community dynamics. Several theories on trophic organisation of biotic communities have explored how resource use, niche breadth, and trophic position vary among organisms. Traditional approaches typically assume invariant trophic traits within species, whereas alternative theories emphasize size-structured relationships, where trophic attributes scale with body size across taxonomic groups – often leading to controversial interpretations. In this study, we examined the relative roles of species identity and body size in the trophic organisation of a large shallow lake fish community using stable isotope analysis based on δ13C and δ15N. By comparing the explanatory power of alternative trophic models, we found that models incorporating both species identity and body size overperformed simpler models that included only one of these factors. Models incorporating full factorial effects of species and body size performed the best, suggesting that ontogenetic changes in resource use are species-specific, while the pure body size model provided only marginal or no explanatory power in the community level analysis. Our analysis revealed that fish in Lake Balaton rely primarily on the open-water basal carbon and nitrogen sources and most species exhibit substantial among-individual variation in both trophic position and isotopic food niche breadth. We conclude that stable isotope analysis, has the potential to provide a detailed understanding of the trophic organisation of lake fish assemblages. Based on our results, we recommend that trophic modelling of fish communities should consider both among species and size-related within species variability. Graphic abstract

Understanding nitrate accumulation processes in deep soil layers is critical for mitigating groundwater contamination risks in intensively managed agr…

Ammonia oxidizers contribute minimally to carbon fixation in the dark ocean despite their abundance at depth, according to enzyme inhibition experiments on water samples from two cruises.

Pelagic-feeding seabirds deliver nutrient subsidies that enhance the productivity, biodiversity, and resilience of terrestrial and marine ecosystems, particularly in nutrient-poor tropical environmen....

A fully validated measurement approach for the determination of oxygen isotope ratios in water using inductively coupled plasma–tandem mass spectrometry (ICP-MS/MS) is described for the first time. Deuterium was used as a reaction gas to mass-shift the oxygen isotopes to the OD3+ product ion, allowing for the removal of polyatomic ions (16O1H+ and 16O1H2+) generated in the plasma that interfere on the less abundant oxygen stable isotopes (17O and 18O). The developed methodology was validated for δVSMOW-SLAP(18O/16O) determinations using four internationally recognized IAEA reference materials, as well as 11 in-house laboratory isotope reference materials that were characterized by isotope ratio mass spectrometry and cavity ring-down spectroscopy. δVSMOW-SLAP(18O/16O) values determined by ICP-MS/MS and the reference methods overlapped within the uncertainties and showed no significant difference for water materials with a low matrix load. Elevated levels of sodium, chloride, and silicon in the matrix lead to isotope ratio shifts of up to 12‰ in both the positive and negative directions. Additionally, comparisons with indicative values from the reference materials demonstrated that δVSMOW-SLAP(17O/16O) determinations are also possible using the ICP-MS/MS approach. While the uncertainty of the developed approach (median uncertainty uc(δVSMOW-SLAP(18O/16O)) = 0.70‰) is not currently able to match that of existing methodologies, it is envisioned that oxygen isotope ratio determinations can be performed alongside multielemental analysis by a wider community for applications where lower uncertainties are not required.

The ocean is losing its oxygen, with hypoxia frequently observed in estuarine and coastal waters. Oxygen concentration changes affect both marine animals and microbe-mediated biogeochemical cycles, su...

Iron plaque (IP) on rice root surfaces has been extensively documented as a natural barrier that effectively reduces contaminant bioavailability and accumulation. However, its regulatory mechanisms in rhizospheric methane oxidation and biological nitrogen fixation (BNF) remain elusive. This study reveals a previously unrecognized function of IP: mediating methanotrophic nitrogen fixation through coupled aerobic methane oxidation and IP reduction (Fe-MOX). Using a hydroponic coculture system integrating methane-oxidizing bacteria and rice seedlings, we demonstrated that IP enhanced microbial methane oxidation by 46.8% and significantly stimulated BNF rate by 33.6%, with methane-derived carbon accounting for 89.1% of the BNF energy source. Notably, dissolved iron removal did not diminish the BNF enhancement, excluding mediation by soluble iron species. Intriguingly, ferrihydrite supplementation at equivalent iron concentrations failed to replicate the BNF stimulation observed with IP, suggesting the indispensability of root-associated iron redox cycling. Mechanistic analyses identified that Methylosinus/Methylocystis species mediated Fe(III) reduction, synergistically collaborating with specific rhizobial strains to execute Fe-MOX-dependent BNF. These findings uncover a previously overlooked yet pronounced contribution of IP to BNF, providing novel insights for developing dual-strategy approaches to mitigate methane emissions and reduce nitrogen fertilizer dependency in paddy ecosystems.

Abstract. Dissolved oxygen (DO) is a fundamental indicator for water quality and ecosystem health, particularly in the context of anthropogenic impacts and climate change. This study presents the firs...

Abstract. Ecological intensification strategies in agriculture, including organic fertilization and diversified crop rotations, aim to reduce nitrogen (N) losses to the environment. However, studies o...

We develop a process-based biomineralization model for dual-clumped isotopes The model explains δ13 ${\delta }^{13}$C-δ18 ${\delta }^{18}$O and Δ47 ${{\Delta }}_{47}$-Δ48 ${{\Delta }}_{48}$ co-va...

Eight months of continuous measurements of methane mole fraction and stable isotopes (δ $\delta $13C, δ $\delta $2H) in an Eastern European urban environment Source mix was dominated by fossil em...

Microbial growth is extremely slow within the first 30 days of thaw. Temperature may drive which taxa are active, but not growth rates Subsurface microbes preferentially produce glycolipids over ...

Microbial carbon use efficiency (CUE) ranged from 0.007 to 0.17 along an elevation gradient in a tropical montane forest CUE and microbial growth increased linearly with elevation, whereas topsoi...

The hydraulic residence time in karst aquifer media controlled the DOM degradation, nitrogen transformation processes, and interaction of microbial activities.

Unique year-round in situ data set of δ13C-CH4 and [CH4] in peat water and in emitted CH4 revealed seasonal dynamics of CH4 processes We found reversal profiles of δ13C-CH4 in peat water between ...

Compound-specific stable isotope analyses of archaeal lipid biomarkers can provide useful information on biogeochemical cycling in marine systems. Whi…