The Qingjiang Estuary mangrove forest, located at the northernmost edge of China's mangrove belt, plays a vital role in maintaining regional ecological balan...

Agricultural ditches are recognized as hotspots of nitrous oxide (N2O) emissions, yet the contributions of different microbial pathways under varying …

Large soil carbon loss under future warming in subtropical forests may not occur due to microbial thermal adjustments.

The respiration of organic matter in soils is not a cell-specific process and can spontaneously occur in an extracellular context.

Low-inflow estuaries (LIEs) have unique biogeochemical cycles that favor nutrient accumulation, making these systems particularly vulnerable to cultural eutrophication. This study investigated a LIE (...

Migratory animals often transport allochthonous materials, energy or organisms from donor to recipient ecosystems, thereby affecting the dynamics of consumers, communities and ecosystems in the recip....

Abstract. Illegal logging is one of the most prevalent environmental infractions in the Amazon, led by organized networks that cause substantial ecological and economic impacts. Official control mecha...

High near-surface nitrogen-fixation rates that promoted the recent growth of the Great Atlantic Sargassum Belt were tied to greater upwelling of phosphorus from the equatorial Atlantic, according to c...

Rationale The Japanese sea lion (Zalophus japonicus), once abundant in Japan, Korea, and Russia, went extinct by the mid-20th century due to hunting and environmental change. This study examines the...

We present a comprehensive study aimed at advancing the NIST accurate isotope ratio infrared spectroscopy (AIR-IS) system (Fleisher et al., Nat. Phys. 17, 889–893, 2021), as a primary direct method for determining the absolute 13C/12C isotope amount ratio of CO2 in air. The AIR-IS system employs a dual-wavelength cavity ring-down spectrometer to measure the abundance of the two most prevalent isotopologues of carbon dioxide: 12C16O2 and 13C16O2. This study introduces key methodological improvements, including quantification of surface-associated effects, enhancement of laser-to-cavity coupling, and refinement of the underlying spectroscopic model. To illustrate its application, we analyze three significant CO2-in-air samples: (i) the natural Northern Continental air NIST Standard Reference Material, SRM® 1720, and (ii) two synthetic mixtures derived from pure CO2 gases sourced from the international P204 comparison study, establishing traceability of their 13C/12C isotope ratios to the International System of Units (SI). Our results highlight AIR-IS’s analytical performance, achieving 0.08‰ long-term precision for the absolute 13C/12C isotope ratio of the Northern Continental air standard monitored over five months, demonstrating agreement in isotope delta values within 0.3(0.2)‰ across a broad range (−1.515 to – 43.119‰ on the Vienna Peedee Belemnite, VPDB scale) for international samples, and constraining surface-associated uncertainty contributions to 0.2‰. AIR-IS measurements further provide a critical SI-traceable reference for CO2-in-air synthetic mixtures. Finally, we determine the 13C/12C isotope amount ratio for VPDB, contributing to independent efforts to refine its accepted value. Taken together, these results reinforce AIR-IS’s potential as a primary direct method for stable carbon isotope ratio measurements with implications for atmospheric research and isotope metrology.

Because atmospheric N2 is highly enriched in 15N15N compared to stochastic expectations, its clumped-isotope signature (Δ30) can serve as a tracer for nitrogen cycling. Despite the environmental and g...

Abstract. We describe a new version of the Chicago Water Isotope Spectrometer (ChiWIS), designed for airborne measurements of vapor-phase water isotopologues in the dry upper troposphere and lower str...

The clumped isotope paleothermometer (Δ47) has been used to reconstruct temperatures from various biogenic carbonate archives. Calibration studies dem…

Molluscan shell-carbonates are extensively used to reconstruct paleo-temperatures at sub-annual resolution. The accurate application of two widely use…

As a major link between oceanic and terrestrial carbon reservoirs, estuarine particulate organic matter (POM) exhibits highly dynamic molecular and is…

In the open ocean, large pelagic predators often share similar food resources and feeding grounds, probably avoiding competition and coexisting through niche partitioning. Building on this hypothesis, we combined spatial distribution data with isotopic ...

Dual isotopes and fluorescence tracked nitrate sources in the Lujiang River. Soil nitrogen and fertilizers were major nitrate sources. Manure and sewage pollution increased downstream with urbanizat...

Temperate forests on their warm and dry distribution limits are expected to be most vulnerable to reductions in water availability. This prediction is mostly based on studies assessing single forest ...

Terrestrial and aquatic ecosystems are connected through energy fluxes partially driven by aquatic organisms that migrate to terrestrial environments during adulthood. According to the thermal perfor...

We combined stable δ13C and δ15N isotope analysis and genetic sexing to investigate whether narwhals with dental anomalies have a distinct long-term foraging ecology. Our results showed no difference....

Phosphate oxygen isotope composition (δ18O(PO43−)) provides critical insights into the sources and transformation processes of phosphorus in aquatic e…

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.

Sulfate is often touted as containing atmospheric oxygen whose isotopic signature can constrain redox, environmental conditions, and biological activi…

Earth’s surficial environments and biosphere have co-evolved through geological time. Constraining past biological activity is thus crucial for unders…

We applied DNA stable isotope probing in a microcosm experiment to understand the role of soil management (till vs no-till) in shaping bacterial carbon cycling. Our hypothesis was that a legacy of disturbance through tillage would exert a selective influence on bacterial growth dynamics, thereby altering bacterial processing of added carbon substrates. We found that lagged growth in tilled soil resulted in delayed bacterial assimilation of xylose and a streamlined, single carbon “channel” characterized by the co-metabolism of xylose and cellulose. In no-till soil, temporally distinct bacterial assimilation of xylose and cellulose by separate carbon “channels” was associated with higher carbon mineralization rates and total mineralization relative to tilled soil. Our findings indicate that soil management practices altered the growth dynamics of active carbon cycling bacteria. Lagged growth associated with a history of disturbance resulted in reduced carbon mineralization.