We juxtapose changes in ostracod taxonomy, morphology (noding) and oxygen (δ¹⁸O) and carbon (δ¹³C) isotopic composition for the last 150 kyr with independent low-resolution salinity proxies. We demonstrate that for Lake Van, salinity is the most important factor influencing the composition of the ostracod assemblage and the formation of nodes on the valves of limnocytherinae species. Ostracod δ¹⁸O shows a higher sensibility towards climatic and hydrological variations than the bulk isotopy.

Systematics in the incorporation of different elements in shells of marine organisms can be used to test calcification models and thus processes involved in precipitation of calcium carbonates. On different scales, we observe a covariation of sulfur and magnesium incorporation in shells of foraminifera, which provides insights into the mechanics behind shell formation. The observed patterns imply that all species of foraminifera actively take up calcium and carbon in a coupled process.

A fingerprinting approach using compound-specific stable isotopes was applied to a lake sediment core to reconstruct erosion processes over the past 150 years in a Swiss catchment. Even though the reconstruction of land use and eutrophication history was successful, the observation of comparatively low δ¹³C values of plant-derived fatty acids in the sediment suggests their alteration within the lake. Thus, their use as a tool for source attribution in sediment cores needs further investigation.

Microbially induced carbonate mineral precipitation (MICP) is a natural process that is also being investigated for subsurface engineering applications including radionuclide immobilization and microfracture plugging. We demonstrate that rates of MICP from microbial urea hydrolysis (ureolysis) vary with different bacterial strains, but rates are similar in both oxygenated and oxygen-free conditions. Ureolysis MICP is therefore a viable biotechnology in the predominately oxygen-free subsurface.

Fatty alcohols (FAs) are major components of surface lipids and can act as surface-active atmospheric organic aerosols, influencing the cloud formation. We identified five secondary FAs in atmospheric aerosols at two temperate forest sites and revealed their distinct seasonal variation for the first time. Our results suggest that they originated mostly from plant wax and could be used as useful tracers for primary biological aerosol particles.

Rare earth mining processes require the removal of topsoil that is mechanically scraped off and relocated to topsoil stockpiles, which proved beneficial for microbial biobanking. But there appears to be a critical time frame for holding topsoil, and rainfall penetration into the stockpile may result in the demise of cyanobacteria. In the longer term, provided conditions are favourable, there may be adequate cyanobacterial survival, at least down to 50 cm, to recolonise the soil surfaces.

Damming did not significantly increase carbon dioxide emissions from the reservoir surface, as shown in a case study in a reservoir constrained within the narrow upper Mekong River valley. This finding might provide some evidence to the green credits for hydropower in China. One-year monitoring of carbon dioxide emissions from the water surface found that the higher emissions were concentrated at the riverine inlets in winter and more related to the mixing process of inflow and reservoir water.

How methane is transported in the sediment is important for the microbial community living on methane. Here we report an observation of a mini-fracture that facilitates the advective gas transport of methane in the sediment, compared to the diffusive fluid transport without a fracture. We found contrasting bio-geochemical signals in these different transport modes. This finding can help to fill the gap in the fracture network system in modulating methane dynamics in surface sediments.

Denitrification is a key process in the soil nitrogen cycle but poorly investigated due to methodical limitations. The ¹⁵N gas flux method is currently the only approach allowing field measurement of denitrification but was subject to bias due to unaccounted fluxes of ¹⁵N-labelled gaseous denitrification products to the subsoil. We used field flux experiments and diffusion–reaction modelling to estimate this source of error and developed an approach to correct denitrification rates.