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The authors wish to make the following corrections to this paper [1]: Please replace Funding section with the funding below: Funding: This research was funded under the NERC DOMAINE programme (NE/K010689/1); NERC LOCAR programme (NER/F3/G13/17/41; NER/T/S/2001/00942), jointly funded by the Environment Agency); a NERC Isotope Geoscience Facility grant (NER/IP/779/0902); and a NERC studentship for Hannah Prior (GT4/94/402), jointly funded by English Nature. We also acknowledge the immense field support from Nigel Crook, supported under a NERC LOCAR grant NER/T/S/2001/00948, and Heather Musgrave, funded through a further NERC studentship NER/S/A/2003/11344. The authors would like to apologize for any inconvenience caused to the readers by the change. The change does not affect the scientific results. The manuscript will be updated and the original will remain online on the article webpage, with a reference to this correction. © 2020 by the author.

The impact of riparian wetlands on the cycling, retention and export of nutrients from land to water varies according to local environmental conditions and is poorly resolved in catchment management approaches. To determine the role a specific wetland might play in a catchment mitigation strategy, an alternative approach is needed to the high-frequency and spatially detailed monitoring programme that would otherwise be needed. Here, we present a new approach using a combination of novel and well-established geochemical, geophysical and isotope ratio methods. This combined approach was developed and tested against a 2-year high-resolution sampling programme in a lowland permeable wetland in the Lambourn catchment, UK. The monitoring programme identified multiple pathways and water sources feeding into the wetland, generating large spatial and temporal variations in nutrient cycling, retention and export behaviours within the wetland. This complexity of contributing source areas and biogeochemical functions within the wetland were effectively identified using the new toolkit approach. We propose that this technique could be used to determine the likely net source/sink function of riparian wetlands prior to their incorporation into any catchment management plan, with relatively low resource implications when compared to a full high-frequency nutrient speciation and isotope geochemistry-based monitoring approach.

The measurement of sulphur isotope (δ34S) values in charred plant remains has the potential to inform understanding of the spatial configuration and ecology of crop production. We investigated the effects of charring, manuring, oxidation and anaerobic soil conditions on modern cereal grain/pulse seed δ34S values, and assessed the effect of chemical pre‐treatment on charred modern and archaeobotanical grain/seed δ34S values. We used these results to interpret δ34S values in archaeobotanical material from Neolithic Çatalhöyük. Our results suggest that δ34S values can be reliably preserved in charred grain/seeds but are subject to influence by anaerobic soil conditions, the effect depending on the timing of flooding in relation to S assimilation.

In this report we outline a method to isolate phosphate as pure Ag3PO4 for waters with high C:P ratios for 18O analysis. This report details a method that can be used to minimise residual organic contamination of the final Ag3PO4, therefore significantly reducing uncertainties in the final interpretation of 18O results. This includes the use of column resins in series to (i) remove the majority of dissolved organic carbon and (ii) isolate/pre-concentrate PO4. This is followed by the use of a modified McLaughlin et al (2004) method for PO4 precipitation, with an additional final hydrogen peroxide clean-up step to remove residual organic matter following precipitation of Ag3PO4. The reagents required for this method are first listed, and then a step-by-step account of the process is outlined. Importantly, it contains adequate detail to be used by other researchers in this field or modified to suit their particular research objectives.

Solute chemistry and stable isotope tracers of NO3 − were used to assess bacterial NO3 − production and denitrification in a High Arctic glacial ecosystem during 2009. Changes in the NO3 − concentration and the δ18O–NO3 in all the proglacial streams revealed that up to 95 % of total NO3 − was most likely bacterially-derived during low flow conditions towards the end of the summer (day of year 250). However, overlapping ranges of δ15N values for snow NH4 +, soil organic matter, cryoconite debris and geological nitrogen in host rocks mean that neither the preferred substrate(s), nor the pathway (i.e. nitrification or simple mineralisation) can be discerned. The most plausible explanation for the bacterial production of NO3 − is nitrification in snowmelt-fed flowpaths through avalanche fans that flank the glacier and along subglacial drainage pathways at the glacier bed. Interestingly, there was no evidence for denitrification in subglacial outflow, which is contrary to earlier research at this site. Instead, increases in the δ15N–NO3 of up to 20 ‰ downstream of the glacier margin, suggests that denitrification in the glacier forefield and/or the sediments that flank it was most discernable during 2009. Our observations therefore suggest that poorly understood temporal variations in the mixing ratio of nitrifying and denitrifying flowpaths occur in this glacial ecosystem.

Sewage contamination in shallow lake sediments is of concern because the pathogens, organic matter and nutrients contribute to the deterioration of the water-bodies' health and ecology. Sediment cores from three shallow lakes (Coneries, Church and Clifton Ponds) within Attenborough nature reserve located downstream of sewage treatment works were analysed for TOC, C/N, δ13C, δ15N, bacterial coliforms and faecal sterols. 210Pb and 137Cs activities were used to date the sediments. Elemental analysis suggests that the source of organic matter was algal and down profile changes in δ13C indicate a possible decrease in productivity with time which could be due to improvements in sewage treatment. δ15N for Coneries Pond are slightly higher than those observed in Church or Clifton and are consistent with a sewage-derived nitrate source which has been diluted by non-sewage sources of N. The similarity in δ15N values (+ 12‰ to + 10‰) indicates that the three ponds were not entirely hydrologically isolated. Analysis by gas chromatography/mass spectrometry (GC/MS) reveals that Coneries Pond had sterol concentrations in the range 20 to 30 μg/g (dry wt.), whereas, those from Clifton and Church Ponds were lower. The highest concentrations of the human-sourced sewage marker 5β-coprostanol were observed in the top 40 cm of Coneries Pond with values up to 2.2 μg/g. In contrast, Church and Clifton Pond sediments contain only trace amounts throughout. Down-profile comparison of 5β-coprostanol/cholesterol, 5β-coprostanol/(5β-coprostanol + 5α-cholestanol) and 5β-epicoprostanol/coprostanol as well as 5α-cholestanol/cholesterol suggests that Coneries Pond has received appreciable amounts of faecal contamination. Examination of 5β-stigmastanol (marker for herbivorous/ruminant animals) down core concentrations suggests a recent decrease in manure slurry input to Coneries Pond. The greater concentration of β-sitosterol in sediments from Church and Clifton Ponds as compared to Coneries is attri

Variations in the 13C/12C ratios of wheat grain at different spatial and temporal scales are examined by analysis of modern samples, including harvests of einkorn and durum wheat from Greece, and serve as a guide to interpreting data for Bronze Age grains from Assiros Toumba. The normal distribution and low variability of δ13C values of einkorn from 24 containers in the Assiros storerooms are consistent with pooling of local harvests, but less likely to represent the harvest of several years or include grain imported from further afield. Correlation between emmer and spelt δ13C values provides strong support for other evidence that these were grown together as a maslin crop. 13C discrimination (Δ) for the Bronze Age samples is estimated to be 2.5‰ larger than at present, and would be consistent with an intensive, horticultural regime of cereal cultivation, possibly involving some watering.

Volcanic sulfate aerosol is emitted from the vents of many active volcanoes, but its origin has not yet been explained. We report the first measurements of the isotopic compositions of near-vent volcanic aerosol sulfate and use the combined sulfur and oxygen isotope systematics of the aerosol and magma at Masaya volcano, Nicaragua, to draw preliminary conclusions about the production mechanism of near-source volcanic sulfate. The sulfate aerosol does not display a significant mass-independent oxygen or sulfur isotopic signature, which suggests that primary volcanic aerosol does not contribute to the larger mass-independent anomalies found in some ambient atmospheric aerosols and as preserved in ice cores. The oxygen isotope composition of the sulfate appeared to become heavier on the particle filters with increasing amount of sample collected and suggests that the δ 18O value of the sulfate aerosol is <8‰. The sulfur isotopic composition of the sulfate did not vary with sample loading on the filters and had a mean δ 34S value of 7.7 ± 0.8‰, similar to that of the magma (6.6 ± 0.2‰). The low Δ17O value, the δ 18O value of the magma (6.6 ± 0.3‰) and the high δ 18O value of atmospheric oxygen (23.5‰) suggest that known atmospheric oxidation pathways at ambient temperatures are not the major routes of production for this sulfate. Instead, the isotopic systematics of aerosol and magma are consistent with sulfate production either by high-temperature equilibration of the magmatic gas mixture with small amounts of atmospheric oxygen or by direct emission of SO4 2− from the magma.

The stable-isotope and trace-element analysis of ostracod calcite are commonly used in palaeoenvironmental reconstruction. We tested the effects on shell composition of a number of methods for the pre-treatment of ostracod valves, including roasting in a vacuum; plasma ashing; and soaking in reagents including hydrogen peroxide, sodium hypochlorite, hydroxylamine hydrochloride solution and sodium dithionite complexing reagent. We found large differences in the geochemical effects of these methods and showed that all have the potential to alter the trace element and stable isotope composition of ostracod valves. We recommend that valves only be cleaned manually, with fine brushes, needles and deionised water whenever possible. However, we recognise that there will be occasions where manual cleaning will be insufficient to remove inorganic or organic contamination. In such cases, we recommend hydrogen peroxide and plasma ashing as good methods for oxygen isotope analysis, if no other analyses are to be performed. For carbon isotope analysis, only plasma ashing should be used. Hydroxylamine hydrochloride is a suitable method for the removal of aluminosilicate material, and sodium hypochlorite is a suitably non-invasive method for the removal of organic material, if subsequent trace element analysis is to be carried out.