We assessed if and how incorporation of exogenous organic carbon (OC) such as straw could affect decomposition of native soil organic carbon (SOC) under different irrigation regimes. Addition of exogenous OC promoted dissolution of native SOC, partly because of increased Fe reduction, leading to more net release of Fe-bound SOC. Yet, there was no proportionate priming of SOC-derived DOC mineralisation. Water-saving irrigation can retard both priming of SOC dissolution and mineralisation.

Fires, including extreme fire seasons, and fire emissions are more common in the Arctic. A review and synthesis of current scientific literature find climate change and human activity in the north are fuelling an emerging Arctic fire regime, causing more black carbon and methane emissions within the Arctic. Uncertainties persist in characterizing future fire landscapes, and thus emissions, as well as policy-relevant challenges in understanding, monitoring, and managing Arctic fire regimes.

Greenhouse gas emissions were measured and compared from natural coastal wetlands and their converted agricultural lands across annual seasonal cycles in tropical Australia. Ponded pastures emitted ~ 200-fold-higher methane than any other tested land use type, suggesting the highest greenhouse gas mitigation potential and financial incentives by the restoration of ponded pastures to natural coastal wetlands.

The relaxed eddy accumulation technique is a method used for measuring fluxes of chemical species in the atmosphere. It relies on a proportionality factor, β, which can be determined using different methods. Also, different techniques for sampling can be used by only drawing air into the measurement system when vertical wind velocity exceeds a certain threshold. We compare different ways to obtain β and different threshold techniques to direct flux measurements for three different sites.

Based on current experimental evidence, climate change will affect up to 90 % of coral reefs worldwide. The originality of this study arises from our recent discovery of an exceptional study site where environmental conditions (temperature, pH, and oxygen) are even worse than those forecasted for the future. While these conditions are generally recognized as unfavorable for marine life, we found a rich and abundant coral reef thriving under such extreme environmental conditions.

We report measured active and passive fluxes and their controlling mechanisms in the northern South China Sea (NSCS). The total fluxes were higher than most reports in open oceans, indicating the significance of NSCS in atmospheric CO₂ uptake and in storing that CO₂ in the ocean’s interior. Winter cooling and extreme events enhanced nutrient availability and elevated fluxes. Global warming may have profound impacts on reducing ocean’s uptake and storage of CO₂ in subtropical–tropical oceans.

UAS remote sensing provides a promising tool for new insights into Si biogeochemistry at catchment scale. Our study on an artificial catchment shows surprisingly high silicon stocks in the biomass of two grass species (C. epigejos, 7 g m⁻²; P. australis, 27 g m⁻²). The distribution of initial sediment properties (clay, Tiron-extractable Si, nitrogen, plant-available potassium) controlled the spatial distribution of C. epigejos. Soil wetness determined the occurrence of P. australis.

We performed Roth C simulations across Australia and assessed the response of soil carbon to changing inputs and future climate change using a consistent modelling framework. Site-specific initialisation of the C pools with measurements of the C fractions is essential for accurate simulations of soil organic C stocks and composition at a large scale. With further warming, Australian soils will become more vulnerable to C loss: natural environments > native grazing > cropping > modified grazing.

Physicochemical determinants of microbiome architecture across continental shelves–slopes are unknown, so we explored the geomicrobiology along 3 m sediment horizons of seasonal (shallow coastal) and perennial (deep sea) hypoxic zones of the Arabian Sea. Nature, concentration, and fate of the organic matter delivered to the sea floor were found to shape the microbiome across the western Indian margin, under direct–indirect influence of sedimentation rate and water column O₂ level.

Europe was affected by an extreme drought in 2018. We show that this drought has increased forest disturbances across Europe, especially central and eastern Europe. Disturbance levels observed 2018–2020 were the highest on record for 30 years. Increased forest disturbances were correlated with low moisture and high atmospheric water demand. The unprecedented impacts of the 2018 drought on forest disturbances demonstrate an urgent need to adapt Europe’s forests to a hotter and drier future.

Spatial and temporal patterns of pCO₂ in the subtropical Dong River basin were mainly affected by C inputs and in-stream metabolism, both of which varied due to differential catchment settings, land cover, and hydrological conditions. CO₂ fluxes in the wet season were 2-fold larger than in the dry season due to high pCO₂ and turbulence caused by high flow velocity. The absence of high CO₂ fluxes in small rivers could be associated with the depletion effect caused by abundant precipitation.

In situ observations over 42 years were used to explore the long-term changes to low-oxygen conditions in the Pearl River estuary. Apparent expansion of the low-oxygen conditions in summer was identified, primarily due to the combined effects of increased anthropogenic inputs and decreased sediment load. Large areas of severe low-oxygen events were also observed in early autumn and were formed by distinct mechanisms. The estuary seems to be growing into a seasonal, estuary-wide hypoxic zone.