Themed collection Geochemistry

Retrospective on microbial transformations of halogenated organics
Prior to the 1960s, knowledge of biological transformations of highly halogenated aliphatic compounds was limited, except in mammalian organisms where enzymatic transformations occurred to rid the body of ingested harmful chemicals.
Environ. Sci.: Processes Impacts, 2020,22, 512-517
https://doi.org/10.1039/C9EM00575G
Fluorophores in surface freshwaters: importance, likely structures, and possible impacts of climate change
Fluorescence spectroscopy is very useful for the characterisation of organic matter in natural water samples. The importance of protein-like fluorescence might be enhanced by several events induced by warming in natural waters such as lake water.
Environ. Sci.: Processes Impacts, 2021,23, 1429-1442
https://doi.org/10.1039/D1EM00273B
Multi-element (C, H, Cl, Br) stable isotope fractionation as a tool to investigate transformation processes for halogenated hydrocarbons
A review that highlights the utility of multi-element compound-specific isotope analysis (CSIA) in halogenated hydrocarbon remediation.
Environ. Sci.: Processes Impacts, 2020,22, 567-582
https://doi.org/10.1039/C9EM00498J
Photochemistry of iron in aquatic environments
Light-induced reduction of Fe(III) delivers Fe(II) as nutrient or substrate for growth of planktonic or sedimentary organisms. Biological uptake, as well as chemical or microbial oxidation of Fe(II) close this photochemically driven iron cycle.
Environ. Sci.: Processes Impacts, 2020,22, 12-24
https://doi.org/10.1039/C9EM00415G
Environmental geochemistry of thioantimony: formation, structure and transformation as compared with thioarsenic
The review presents a way of comparing environmental geochemistry between thioantimony and thioarsenic, summarizing the latest knowledge about their formation, structure and transformation.
Environ. Sci.: Processes Impacts, 2021,23, 1863-1872
https://doi.org/10.1039/D1EM00261A
Emerging investigator series: critical review of photophysical models for the optical and photochemical properties of dissolved organic matter
Photophysical models for dissolved organic matter optical properties and photochemistry are critically reviewed.
Environ. Sci.: Processes Impacts, 2020,22, 1139-1165
https://doi.org/10.1039/D0EM00056F
Cross-ecosystem nutrient subsidies in Arctic and alpine lakes: implications of global change for remote lakes
Environmental change is continuing to affect the flow of nutrients, material and organisms across ecosystem boundaries. In this review, we synthesize current knowledge of cross-ecosystem nutrient subsidies between Arctic and alpine lakes and their surrounding terrain, cryosphere, and atmosphere.
Environ. Sci.: Processes Impacts, 2020,22, 1166-1189
https://doi.org/10.1039/C9EM00528E
Positive matrix factorization on source apportionment for typical pollutants in different environmental media: a review
A bibliometric analysis of published papers with the key words “positive matrix factorization” and “source apportionment” in ‘Web of Science’, reveals that more than 1000 papers are associated with this research and that approximately 50% of these were produced in Asia.
Environ. Sci.: Processes Impacts, 2020,22, 239-255
https://doi.org/10.1039/C9EM00529C
Unexpectedly high dimethyl sulfide concentration in high-latitude Arctic sea ice melt ponds
Dimethyl sulfide (DMS) production in the northern Arctic Ocean has been considered to be minimal because of high sea ice concentration and extremely low productivity.
Environ. Sci.: Processes Impacts, 2019,21, 1642-1649
https://doi.org/10.1039/C9EM00195F
Biological calcium carbonate with a unique organic–inorganic composite structure to enhance biochar stability
The inorganic components in Bio-CaCO3 catalyze the deoxygenation of biochar and increase the degree of aromatization of the carbon matrix. The stable pyridinic-N structures are doped into the carbon skeleton, which further improves the stability of biochar.
Environ. Sci.: Processes Impacts, 2021,23, 1747-1758
https://doi.org/10.1039/D1EM00247C
Identifying sources of groundwater salinity and major hydrogeochemical processes in the Lower Kabul Basin aquifer, Afghanistan
The origin of groundwater salinity and major hydrogeochemical processes in the LKB aquifer were investigated using hydrogeochemical and HCA methods. The results indicate that evaporitic lacustrine deposits are the major source of salinity in the aquifer.
Environ. Sci.: Processes Impacts, 2021,23, 1589-1599
https://doi.org/10.1039/D1EM00262G

Interannual, summer, and diel variability of CH4 and CO2 effluxes from Toolik Lake, Alaska, during the ice-free periods 2010–2015
CH4 and CO2 fluxes from Toolik Lake obtained for the first time with eddy covariance during ice-free periods 2010–2015.
Environ. Sci.: Processes Impacts, 2020,22, 2181-2198
https://doi.org/10.1039/D0EM00125B
Microbial genetic potential for xenobiotic metabolism increases with depth during biofiltration
Microbial genetic potential for the biotransformation of xenobiotics and antibiotic resistance increases with depth during biofiltration.
Environ. Sci.: Processes Impacts, 2020,22, 2058-2069
https://doi.org/10.1039/D0EM00254B
Anaerobic respiration pathways and response to increased substrate availability of Arctic wetland soils
Divergent soil biogeochemical conditions will determine the fate and pathways of labile carbon released during permafrost thaw, thereby influencing the production of greenhouse gas mixtures and radiative forcing of tundra soils.
Environ. Sci.: Processes Impacts, 2020,22, 2070-2083
https://doi.org/10.1039/D0EM00124D

Surface precipitation of Mn2+ on clay minerals enhances Cd2+ sorption under anoxic conditions
Under anoxic conditions, clay minerals sorb dissolved Mn(II) predominantly by forming surface precipitates, which increase Cd sorption.
Environ. Sci.: Processes Impacts, 2020,22, 1654-1665
https://doi.org/10.1039/D0EM00155D
Physico-chemical factors controlling the speciation of phosphorus in English and Welsh rivers
Phosphorus cycling in the environment.
Environ. Sci.: Processes Impacts, 2020,22, 1688-1697
https://doi.org/10.1039/D0EM00093K

Composition and photo-reactivity of organic matter from permafrost soils and surface waters in interior Alaska
Yedoma permafrost soils are especially susceptible to abrupt thaw due to their exceptional thickness and high ice content.
Environ. Sci.: Processes Impacts, 2020,22, 1525-1539
https://doi.org/10.1039/D0EM00097C
Iron and iron-bound phosphate accumulate in surface soils of ice-wedge polygons in arctic tundra
Iron accumulation in shallow tundra soils promotes adsorption of phosphate from soil solution, sequestering high concentrations of potentially bioavailable phosphorus.
Environ. Sci.: Processes Impacts, 2020,22, 1475-1490
https://doi.org/10.1039/D0EM00142B

Interactions of ferrous iron with clay mineral surfaces during sorption and subsequent oxidation
Under anoxic conditions, clay minerals sorb dissolved Fe(II) predominantly by forming surface precipitates, which transform into Fe(III)-phases upon aeration.
Environ. Sci.: Processes Impacts, 2020,22, 1355-1367
https://doi.org/10.1039/D0EM00063A

Assessing the prevalence, products, and pathways of dissolved organic matter partial photo-oxidation in arctic surface waters
Isotope tracer experiments reveal that rates of dissolved organic matter partial photochemical oxidation are considerably underestimated in arctic surface waters.
Environ. Sci.: Processes Impacts, 2020,22, 1214-1223
https://doi.org/10.1039/C9EM00504H

Quantitative measures of myo-IP6 in soil using solution 31P NMR spectroscopy and spectral deconvolution fitting including a broad signal
Inositol phosphates, particularly myo-inositol hexakisphosphate (myo-IP6), are an important pool of soil organic phosphorus (P) in terrestrial ecosystems.
Environ. Sci.: Processes Impacts, 2020,22, 1084-1094
https://doi.org/10.1039/C9EM00485H
Use of optical properties for evaluating the presence of pyrogenic organic matter in thermally altered soil leachates
Optical measurements reveal the presence of pyrogenic organic matter in laboratory heated soil leachates, indicating their potential for application in field measurements.
Environ. Sci.: Processes Impacts, 2020,22, 981-992
https://doi.org/10.1039/C9EM00413K
Impact of bromide exposure on natural organochlorine loss from coastal wetland soils in the Winyah Bay, South Carolina
Naturally formed halogenated organic compounds are common in terrestrial and marine environments and play an important role in the halogen cycle.
Environ. Sci.: Processes Impacts, 2020,22, 642-652
https://doi.org/10.1039/C9EM00604D
Sources and sinks of chloromethane in a salt marsh ecosystem: constraints from concentration and stable isotope measurements of laboratory incubation experiments
Chloromethane (CH3Cl) is the most abundant long-lived chlorinated organic compound in the atmosphere and contributes significantly to natural stratospheric ozone depletion.
Environ. Sci.: Processes Impacts, 2020,22, 627-641
https://doi.org/10.1039/C9EM00540D
How did the bacterial community respond to the level of urbanization along the Yangtze River?
The response of bacteria communities to the urbanization level.
Environ. Sci.: Processes Impacts, 2020,22, 161-172
https://doi.org/10.1039/C9EM00399A
Emerging investigator series: mercury mobility and methylmercury formation in a contaminated agricultural flood plain: influence of flooding and manure addition
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.
Environ. Sci.: Processes Impacts, 2019,21, 2008-2019
https://doi.org/10.1039/C9EM00257J
Plant rhizosphere, soil microenvironment, and functional genes in the nitrogen removal process of bioretention
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).
Environ. Sci.: Processes Impacts, 2019,21, 2070-2079
https://doi.org/10.1039/C9EM00296K
Potential impacts of anthropogenic nutrient enrichment on coral reefs in the South China Sea: evidence from nutrient and chlorophyll a levels in seawater
Anthropogenic nutrient enrichment caused macroalgal blooms and further resulted in coral reef degradation in coastal and some remote reef areas of the SCS.
Environ. Sci.: Processes Impacts, 2019,21, 1745-1753
https://doi.org/10.1039/C9EM00331B
Assessing thermodynamic parameter sensitivity for simulating temperature responses of soil nitrification
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.
Environ. Sci.: Processes Impacts, 2019,21, 1596-1608
https://doi.org/10.1039/C9EM00310J
About this collection
This web collection features research articles published in Environmental Science: Processes & Impacts focussed on geochemistry and biogeochemistry.