Themed collection Geochemistry

The distribution of trace elements (TEs) in the bituminous sands is dichotomous: V, Ni, Mo, Se and Re are found predominantly in the bitumen fraction, and all other TEs in the mineral fraction.

Antimony (Sb) has gained increased attention over the past few decades due to its possible detrimental effects on biota and its potential to leach and disperse from contaminated soils.

The nano-self-assembly of natural organic matter (NOM) profoundly influences the occurrence and fate of NOM and pollutants in large-scale complex environments.

Electrochemically active microorganisms (EAMs) play an important role in the fields of environment and energy.

This paper summarizes the atmospheric release of Hg, distribution of air Hg concentration, human exposure to MeHg and health impacts caused by Hg pollution in China.

Microplastic (MP) particles are ubiquitous in aquatic environments where they become exposed to UV-irradiation and environmental particles with subsequent alteration of surface properties.

Comprehensive analysis of the seasonal variations in groundwater chemistry and quality and health risks in PRD domestic wells highlighted elevated concentrations of As and NO₃⁻, as exacerbated by heavy rainfall during the wet season.

Soil salinization inhibited straw mineralization and induced a priming effect. The peak straw mineralization and priming effect occurred earlier with increasing soil salinity.

Nanoscale mixed inorganic–organic Fe–Ca–P-OM co-precipitates formed in sediments of eutrophic peat lake after Fe treatment increase seasonal internal P loading.

This study presents photochemical (singlet oxygen), optical properties (absorbance, fluorescence), photobleaching and photomineralization experiments of wildfire ash leachates. Results indicate that ash leachates are more labile than control soils.

The connections between terrestrial DP sources and aquatic DP sinks were comprehended in a small-dammed watershed through an integrated understanding of DP transport patterns, export controls, and their fate over dry–wet–dry transitions.

Siderite is stabilised against oxidation in the presence of Low Molecular Weight Organic Acids (LMWOAs) with implications for iron mineral transformations and therefore contaminant and nutrient cycling.

We describe a robust and flexible protocol to collect water-soluble chemicals from leaf surfaces for atmosphere-biosphere interaction studies.

Artemisia annua litter produced in soil contaminated with 15 and 30 g kg⁻¹ of petroleum exhibited significantly lower decomposition rates than that from uncontaminated soil.

Coccolithophores are biogeochemically and ecologically important phytoplankton that produce calcium carbonate scales, or coccoliths. Here, we show that one species of coccolithophore grows coccoliths with uneven distribution of Sr, in contrast to current fractionation model theory.

The uptake of total gaseous mercury (TGM) by Korean forest foliage is mainly affected by local wind speed, boosting its passage and absorption. Mercury levels and isotopic signatures in litter and topsoil fluctuate, particularly in areas with high wind speed, temperature, and low elevation.

To study the geogenic processes of naturally occurring radioactive materials' distribution, a transboundary Himalayan river (Punarbhaba) is chosen due to its trivial anthropogenic impacts.

In aquatic systems, dissolved organic matter (DOM) has important ecological and biogeochemical functions, where the molecular composition of DOM has larger-scale implications for climate change and global carbon cycles.

This study indicates that in alkaline media, carbonate slightly inhibits ferrihydrite transformation and suppresses goethite formation, but promotes hematite formation, which has important implications for elemental biogeochemical cycles.

Despite the importance of structural control on metal stable isotope fractionation in inorganic and abiotic systems, the link between metal structural changes and related isotopic fractionation during reactions with organic surfaces and live cells remains poorly established.

We showed that oligotrophic coastal marine areas are susceptible to the deposition of pollen and aerosols from open-fire biomass burning, which alter Cu-binding organic ligands in the sea surface microlayer.

We studied the transformation of ⁵⁷Fe-labelled ferrihydrite and lepidocrocite mixed with a flooded paddy soil by using ⁵⁷Fe-Mössbauer spectroscopy.

The protonation state of dissolved organic matter (DOM) impacts its structure and function in natural and engineered environmental systems, including DOM's ability to absorb light and form photochemically produced reactive intermediates (PPRI).

The soil environment in regions with a high arsenic geological background may have enabled microbial adaptation, through co-selection mechanisms, to withstand the introduction of exogenous antibiotics.

Prehistoric and modern records of Hg in peats from the lower Amur River basin, eastern Asia, were investigated.

Addition of microplastics (MP) to soil has the potential to increase soil water repellency. Absorption of soil abundant substances on MP surfaces has the potential to overcome MP inherent hydrophobicity.

Methylmercury formed in anoxic reservoirs associates with organic-rich particles and is exported downstream.

This study investigates ecological consequences from the combined provenance (natural and manmade) of fifteen metal(oid)s (Na, Al, K, Ti, Cr, Mn, Co, Zn, As, Rb, Sb, Cs, Ba, Th, and U) from a major Indo-Bangla transboundary river (Teesta).

The formation and dynamic partitioning of As species in the water column of a large oligo-mesotrophic lake is driven by biological processes.

The over-use of synthetic nitrogen (N) fertilisers for crop production can cause environmental pollution through leaching and gaseous losses, resulting in low N use efficiency (NUE).

Under global warming, invasive cyanobacteria, can migrate northward and colonize lakes in permafrost-affected territories. This study tests the potential growth of M. aeruginosa onto various organic-rich solutions of those regions.

At mercury (Hg)-contaminated sites, streambank erosion can act as a main mobilizer of Hg into nearby waterbodies.

Cr(III) oxidation and Cr(VI) occurrence corresponds to regions of cation-exchange induced Mn-carbonate dissolution.

Batch sorption–desorption of Zn, Cu, Fe, Mn, B and S onto phyto-biochars prepared from lantana, pine needles and wheat straw by pyrolysis at 300 °C and 450 °C were studied in a multi-ionic system.

Photochemical production of hydrogen peroxide (H₂O₂) may not the dominant source of H₂O₂ in Lake Erie, where toxin-forming harmful algal blooms follow high concentrations of H₂O₂.

The rate and pathway of ferrihydrite transformation in soil depends on the properties of the soil pore water and diffusion processes.

Marine chromophoric dissolved organic matter (m-CDOM) mediates many vital photochemical processes in the surface ocean.

Heteroaggregation of microplastic and ferrihydrite leads to sedimentation and therefore removal of microplastic from the water column.

Beaver ponds act as biological "hotspots" with unique geochemistry and microbiomes in fire-impacted systems.

Microbial processes can be involved in the remobilization of uranium (U) from reduced sediments under O₂ reoxidation events such as water table fluctuations.

Aluminum in schwertmannite structure increases the proportion of covalent bonding with adsorbed arsenates.

Biogeochemical cycling of S, Fe, and C in the hyporheic zone is influenced by dynamic hydrologic conditions.

We studied the extent and mode of thallium adsorption onto several phyllosilicate minerals. Thallium, in analogy to cesium, strongly adsorbs onto micaceous phyllosilicates in soils and sediments via complexation in siloxane cavities.

Porewater geochemistry in a lanthanum-remediated lake reveal that phosphorus mobility depends on the interplay between carbon and iron.

Australian anthropogenic emissions of mercury have decreased by a factor of two since 2000, with implications for atmospheric mercury concentrations and deposition to the Australian continent.

Marine heatwave conditions diminished (micro)macronutrient vertical transport, reducing (micro)macronutrient inventories and net community production when external nutrient sources were absent.

Halogens in soil are closely linked to abiotic processes, biota and pedogenesis, and thus to the availability of water; vertical halogen depth patterns become less pronounced with increasing dryness.

The low molecular weight fraction of peat porewater is enriched in DOC, anions, oxyanions, alkalis and some trace metals. An increase in the active layer depth can liberate a large amount of labile metals and nutrients from the peat.

The distribution and chemical speciation of micronutrient selenium is reported for the first time in twenty alpine lakes (Pyrenees, France–Spain).

A holistic multi-analyses (led by Hg stable isotope analysis), multi-media, multi-site approach to improving contaminated site Hg geochemistry, particularly process tracing.

HA promotes enzymatic hydrolysis of phytate as shown by the increase in nucleation of P_i-bearing particles, which is achieved by conformation change to stabilize a catalytic domain resulting from noncovalent phytase–HA interaction.

Surface precipitation has been shown to occur on rapid time scales in clay and metal oxide mineral systems.

This study shows a feasible cultivation-independent method by MMI coupled with high-throughput sequencing to identify in situ microbes actively, various microbes were recognized for the first time, the OPH genes were involved in CPF metabolism.

DIC generation in carbonate dissolution in acidic granitic-soil is promoted by H₂SO₄, perturbed by HNO₃, little affected by organic acids.

We compared how FTICR-MS characterization of riverine dissolved organic matter varied across four sample pre-treatment and instrument ionization methods to provide guidelines for future researchers utilizing FTICR-MS in environmental analyses.

Schematic showing how voltammetric microelectrodes were used to profile arctic lake sediments, where different locations contained different distributions of redox-active species.

Under anoxic conditions, clay minerals sorb dissolved Fe(II) predominantly by forming surface precipitates, which transform into Fe(III)-phases upon aeration.

Isotope tracer experiments reveal that rates of dissolved organic matter partial photochemical oxidation are considerably underestimated in arctic surface waters.

Inositol phosphates, particularly myo-inositol hexakisphosphate (myo-IP₆), are an important pool of soil organic phosphorus (P) in terrestrial ecosystems.

Optical measurements reveal the presence of pyrogenic organic matter in laboratory heated soil leachates, indicating their potential for application in field measurements.

Naturally formed halogenated organic compounds are common in terrestrial and marine environments and play an important role in the halogen cycle.

Chloromethane (CH₃Cl) is the most abundant long-lived chlorinated organic compound in the atmosphere and contributes significantly to natural stratospheric ozone depletion.

The response of bacteria communities to the urbanization level.

We investigated the release of mercury from soil to soil solution and the formation of methylmercury in polluted agricultural floodplain fields during a flooding incubation experiment.

The coupling effect of plant, soil, and microbes in bioretention provides conditions conductive for nitrogen (N) removal via nitrification, accretion, denitrification, and dissimilatory nitrate reduction to ammonium (DNRA).

Anthropogenic nutrient enrichment caused macroalgal blooms and further resulted in coral reef degradation in coastal and some remote reef areas of the SCS.

The sensitivity of SQRT model-estimated parameters varied over a temperature gradient whereas no variation in MMRT model-estimated parameters, in simulating temperature responses of soil nitrification over the temperature range, was observed.