Rapid shift in methane carbon isotopes suggests microbial emissions drove record high atmospheric methane growth in 2020-2022.

The growth rate of the atmospheric abundance of methane (CH) reached a record high of 15.4 ppb yr between 2020 and 2022, but the mechanisms driving the accelerated CH growth have so far been unclear. In this work, we use measurements of the C:C ratio of CH (expressed as C) from NOAA's Global Greenhouse Gas Reference Network and a box model to investigate potential drivers for the rapid CH growth.

Iron Stable Isotopes in Bulk Soil and Sequential Extracted Fractions Trace Fe Redox Cycling in Paddy Soils.

In paddy soils, iron (Fe) forms are highly influenced by the seasonal redox changes and leave detectable isotope signals because of fractionation between different Fe forms. Here, we present Fe concentrations and Fe isotope compositions (expressed as δFe values) in a paddy soil profile from Suzhou, China. Light Fe isotopes were enriched in two iron-accumulation layers (Br3 and G1) with high Fe concentrations.

Stable Sulfur Isotopes Revealed a Major Role of Transition-Metal Ion-Catalyzed SO Oxidation in Haze Episodes.

Secondary sulfate aerosols played an important role in aerosol formation and aging processes, especially during haze episodes in China. Secondary sulfate was formed via atmospheric oxidation of SO by OH, O, HO, and transition-metal-catalyzed (TMI) O. However, the relative importance of these oxidants in haze episodes was strongly debated.

Triple oxygen isotopic evidence for atmospheric nitrate and its application in source identification for river systems in the Qinghai-Tibetan Plateau.

Nitrate source identification in river systems is important for water quality management. Recently, the oxygen isotopic anomaly of nitrate in atmospheric deposition (ΔO) is used to identify unprocessed atmospheric nitrate in river systems to reduce the uncertainty caused by the wide range of δO. In high-elevation regions, such as the Qinghai-Tibetan Plateau (QTP) featured with lower temperature and pressure as well as strong radiation, the ΔO might be different from that in low-elevation regions, but no relevant studies have been reported.