Environmental context. Heating of soils under wildfires can substantially reduce their ability to absorb rainfall, causing reduced vegetation recovery and increased erosion and flooding. This study examines, for the first time, the chemical changes in soil organic matter associated with heating in the oxygen-limited conditions typical under many wildfires. There was a noticeable tendency for production of non-polar compounds, which may ultimately contribute to a more persistent form of soil water repellency with important implications for managing fire affected terrain.

Environmental context. Rock surfaces are often covered with a dark coating called desert varnish that can capture and retain air pollutants. A field portable X-ray fluorescence spectrometer was used for direct non-destructive analysis of varnished rocks in the fallout zones of two coal-fired power plants. At one power plant where tracer studies had been carried out, the highest concentration of elements including Cr, As, Pb and Zn in the rock varnish samples, coincides with the peak tracer concentration locations.

Environmental context. Live bacteria are widely used to remove toxic metals from contaminated environments. We use the metal-resistant bacterium Cupriavidus metallidurans, in both model solutions and aqueous extracts of soils, to investigate the complexation and competition effects on Cd and Pb uptake. Accumulation of Cd was more affected by competition with Ca, Mg and Zn, whereas Pb accumulation was more influenced by complexation with humic acids. The study highlights the need to consider chemical site-specificity in the removal of metals from contaminated environments.

Environmental context. As atmospheric CO₂ levels rise due to human activities, more of the gas dissolves in the oceans, increasing their acidity. The effect of these seawater changes on marine organisms is largely unknown. We examine the consequences of higher CO₂ levels on the production by plankton of dimethyl sulfide, a climatically active gas. We find that higher CO₂ levels leads to lower concentrations of dimethyl sulfide in the seawater, which has potentially important implications for the future climate.

Environmental context. The occurrence of pesticides in remote areas such as high mountains and the Arctic demands an understanding of their regional environmental fate. We investigate the levels and sources of currently used pesticides and legacy pesticides in the air and seawater of the German Bight. Volatilisation from local surfaces and long-range transport were the major sources of these chemicals to the air, whereas riverine input and atmospheric deposition by air–seawater exchange were the main sources of these chemicals to the seawater.

Environmental context. The recently developed diffusive gradients in thin-films (DGT)-planar optode sandwich probe uses extremely thin resin binding layers, separated from the medium of interest by a very thin material diffusive layer. This work investigates how these changes to the physical nature of a DGT probe are likely to change the interpretation of trace metal measurements in solutions, soils and sediments by using a combination of experimental measurements in well characterised solutions and spiked soils, and advanced reactive transport modelling.