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Background Milk is one of the most important food sources for human nutrition. The chemical composition of milk varies depending on many factors and may influence its nutritional value and safety. Metabolomics has recently become one of the major approaches applied to understand the chemical profiles and dynamic changes in milk products. Scope and approach The increase in the application of metabolomics in milk studies is, in large part, due to the development of high-throughput and high-sensitivity instruments and efficient chemometrics. This review focuses on the changing metabolites in milk, which are relevant to both the inherent factors, such as cow breed, dairy animal species and lactation stage, and external factors, including diet, season, geographic origin, disease, processing and storage stability. Additionally, the applications of candidate biomarkers for milk authentication are reviewed. Key findings and conclusions The candidate biomarkers identified in previous studies are listed in this review. Also, some metabolites, which could be used as robust biomarkers, such as choline, citrate, valine, hippuric acid, 2-butanone, lactate and some fatty acids, for milk quality, traceability and safety studies are summarized. Challenges for this scientific field are also addressed.

This study is the first to provide a comprehensive characterization of the liquid and volatile fractions of whole goat milk powder (GMP). Robust nuclear magnetic resonance (NMR)- and gas chromatography-mass spectrometry (GC-MS)-based chemical fingerprinting methods were optimized and implemented. The untargeted 1H-NMR analysis resolved 44 metabolites in the liquid fractions of GMP. The NMR fingerprinting technique effectively identified metabolites coming from the aliphatic, sugar, and aromatic regions that can be important in defining the technological properties and quality of the GMP. The untargeted headspace gas chromatography-mass spectrometry fingerprinting was able to detect a total of 50 volatiles including alkanes, ketones, alcohols, aromatics, alkenes, aldehydes, esters, acid, and sulfur compounds. The GMP was dominated by volatiles in the alkane group, while only a few esters were detected. Goat milk is a premium product and vulnerable to fraudulent activities such as adulteration or counterfeit. Therefore, proper characterization and identification is a crucial first step to verify its authenticity and quality.

Fresh milk is an important source of essential mineral supplement for humans. However, the levels of trace elements in milk are an important component of its safety and quality. Trace elements also act as a bio-indicator of agricultural pollution. Samples of raw cow milk (n = 68), animal feed [forage (n = 36) and concentrates (n = 14)], and water (n = 35) were collected from different agro-climatic regions of Sri Lanka. The concentrations of 15 trace elements including toxic heavy metals such as Cd, Pb, and As were quantified using inductively coupled plasma mass spectrometry after microwave-assisted digestion. Among the studied trace elements, the mean elemental concentrations of Se, Cd, As, and Cu in cow milk were 18.1, 1.45, 7.35, and 71.7 μg L−1, respectively. The mean concentrations of these elements in forage were 0.216, 0.066, 0.046, and 9.21 mg kg−1, and in concentrate feed were 0.329, 0.202, 0.229, and 2.28 mg kg−1, respectively. The As content of the studied milk was well below the maximum permissible level while 15% of the samples had Pb exceeding the permissible limit of 20 μg L−1. However, As, Cd, and Pb levels in drinking water provided to animals were well below the WHO permissible limits. The results of this study revealed that the trace elements in cow milk depend mainly on the feed, and hence, levels of these contaminants in feed materials should be monitored. Although due to the consumption of milk, the populations have a minor exposure to trace elements and also minimum health risks, a detailed study with a large number of samples is highly recommended.

This work presents the first use of Sr isotope ratios for determining the provenance of bovine milk from different regions of Slovenia. The analytical protocol for the determination of 87Sr/86Sr isotope ratio was optimised and applied to authentic milk samples. Considerable variability of 87Sr/86Sr ratios found in Slovenian milk reflects the substantial heterogeneity of the geological background of its origin. The results, although promising, cannot discount possible inter-annual or annual variation of the Sr isotopic composition of milk. The 87Sr/86Sr ratios of groundwater and surface waters are in good correlation with milk, indicating that the Sr isotopic fingerprint in milk is reflective of cow drinking water. The 87Sr/86Sr ratio has the potential to distinguish between different milk production areas as long as these areas are characterised by geo-lithology. Discriminant analysis (DA) incorporating the elemental composition and stable isotopes of light elements showed that 87Sr/86Sr ratio together with δ13Ccas and δ15Ncas values have the main discrimination power to distinguish the Quaternary group (group 6) from the others. Group 1 (Cretaceous: Carbonate Rocks and Flysch) is associated with Br content, 1/Sr and δ18Ow values. The overall prediction ability was found to be 63.5%. Pairwise comparisons using OPLS-DA confirmed that diet and geologic parameters are important for the separation.

Infant formula (IF), regarded as the optimal substitute for human breast milk, is very important for infant growth and development. Phospholipids (PLs) are ubiquitous components of infant formula as they have good emulsifier properties in addition to their nutritional and biological functions. In this study, the PL contents in four different commercial IF brands (indicated as A, M, O, and W) were characterized and quantified using optimized 31P NMR spectroscopy. PLs (nine) were identified and quantified, and among these, phosphatidylethanolamine and sphingomyelin occurred at lower concentrations (5.72 and 8.89 mg/100 g, respectively) in IFs from brand O, whereas phosphatidic acid was higher (2.83 mg/100 g) in IFs from brand W. In summary, 31P NMR spectroscopy, combined with the multivariate data analysis, proved to be an effective analytical toolbox for evaluating the PL contents in IF and the comparative differences between IF brands.

The relative availability of alternative organic matter sources directly influences trophic interactions within ecological communities. As differences in trophic ecology can alter the productivity of communities, understanding spatial variability in trophic structure, and the drivers of variability, is vital for implementing effective ecosystem‐based management. Bulk stable isotope analysis (δ¹³C and δ¹⁵N) and mass balance calculations were used to examine patterns in the contribution of organic matter derived from macroalgae to food webs supporting temperate reef fish communities in two contrasting coastal waterways on the South Island of New Zealand: Fiordland and the Marlborough Sounds. Ten fish species common to both regions were compared, with up to 40% less organic matter from macroalgae supporting omnivorous species in the Marlborough Sounds. The largest differences in trophic position were found in those species exploited by fisheries. Furthermore, stratified surveys of abundance and species biomass combined with trophic position data were used to calculate regional differences in the contribution of macroalgae to whole fish communities in terms of density of biomass. In Fiordland, over 77% of the biomass of exploited reef fishes was supported by macroalgae, compared with 31% in the Marlborough Sounds. Surveys of macroalgal density and species composition in the two regions indicated that regional differences in trophodynamics may be explained by a lack of macroalgal inputs to the food web in the Marlborough Sounds. The findings demonstrate large regional differences in the incorporation of benthic and pelagic sources of organic matter to food webs supporting reef fish communities, highlighting the need for ecosystem‐based approaches to management to recognize spatial variability in primary production supporting coastal food webs.

Sewage, waste organic matter from domestic and municipal wastewater, causes increased secondary productivity, eutrophication and trace metal contamination, reduced oxygen levels, and biodiversity which can lead to ecological disturbances in the natural aquatic ecosystem. The impact of sewage-derived organic matter (SDOM) on the nearshore marine ecosystem of the Otago Coast was assessed before, and 15 years after upgrade of the Dunedin sewage treatment plant. Carbon and nitrogen isotopic ratios in the tissues of sentinel organisms were used as bioindicators to elucidate the primary sources of nutrition the coastal environment. Mytilus galloprovincialis, a marine bivalve, exhibited a strong influence of SDOM from two sites in 2001. In 2015, M. galloprovincialis had a trophic enrichment factor of 3‰ (δ15N) and 1‰ (δ13C) when compared to the marine particulate organic matter (POM), suggestive of a dietary change away from the SDOM. Suspended POM collected from riverine and estuarine sources revealed other possible nitrogen sources from human-driven activities such as pastoral farming, application of organic manure and inorganic fertilisers, nitrification of ammonium from semi-urban septic tanks, and animal organic waste residues.

Milk is a favorable for humans due to its nutritional composition. Metabolites in milk relevant to human health have received increased attention. Proton nuclear magnetic resonance (1H-NMR) is commonly used for water-soluble metabolites due to rapid data acquisition and excellent precision. Extraction to separate fats and proteins from the metabolites is necessary to obtain high quality spectra. In the present work, various extraction procedures were compared for 1H-NMR. The mass of milk for extraction was also optimized. Overall, 2/1 (v/v) methanol/skim milk was selected to be the most efficient system. The best precision was obtained for 500 to 600 mg milk powder redissolved in 2 mL water and 0.5 mL skim milk for the subsequent extraction. This study provides a sample preparation protocol for milk metabolomics that may be appropriate for other samples.

Dairy products occupy a special place among foods in contributing to a major part of our nutritional requirements, while also being prone to fraud. Hence, the verification of the authenticity of dairy products is of prime importance. Multiple stable isotopic studies have been undertaken that demonstrate the efficacy of this approach for the authentication of foodstuffs. However, the authentication of dairy products for geographic origin has been a challenge due to the complex interactions of geological and climatic drivers. This study applies stable isotope measurements of d2H, d18O, d13C and d15N values from casein to investigate the inherent geo-climatic variation across dairy farms from the South and North Islands of New Zealand. The stable isotopic ratios were measured for casein samples which had been separated from freeze-dried whole milk samples. As uniform feeding and fertilizer practices were applied throughout the sampling period, the subtropical (North Island) and temperate (South Island) climates were reflected in the variation of d13C and d15N. However, highly correlated d2H and d18O (r = 0.62, p = 6.64 &times, 10&minus, 10, a = 0.05) values did not differentiate climatic variation between Islands, but rather topographical locations. The highlight was the strong influence of d15N towards explaining climatic variability, which could be important for further discussion.

ESA's SMART-1 mission to the Moon achieved record firsts such as: 1) first Small Mission for Advanced Research and Technology; with spacecraft built and integrated in 2.5 years and launched 3.5 years after mission approval; 2) first mission leaving the Earth orbit using solar power alone; 3) most fuel effective mission (60 L of Xenon) and longest travel (13 months) to the Moon!; 4) first ESA mission reaching the Moon and first European views of lunar poles; 5) first European demonstration of a wide range of new technologies: Li-Ion modular battery, deep-space communications in X- and Ka-bands, and autonomous positioning for navigation; 6) first lunar demonstration of an infrared spectrometer and of a Swept Charge Detector Lunar X-ray fluorescence spectrometer; 7) first ESA mission with opportunity for lunar science, elemental geochemistry, surface mineralogy mapping, surface geology and precursor studies for exploration; 8) first controlled impact landing on the Moon with real time observations campaign; 9) first mission supporting goals of the International Lunar Exploration Working Group (ILEWG) in technical and scientific exchange, international collaboration, public and youth engagement; 10) first mission preparing the ground for ESA collaboration in Chandrayaan-1, Chang’ E1 and future international lunar exploration. We review SMART-1 highlights and new results that are relevant to the preparation for future lunar exploration. The technology and methods had impact on space research and applications. Recent SMART-1 results are relevant to topics on: 1) the study of properties of the lunar dust, 2) impact craters and ejecta, 3) the study of illumination, 4) radio observations and science from the Moon, 5) support to future missions, 6) identifying and characterising sites for exploration and exploitation. On these respective topics, we discuss recent SMART-1 results and challenges. We also discuss the use of SMART-1 publications library. The SMART-1 archive observations have been used to support the goals of ILEWG. SMART-1 has been useful to prepare for Kaguya, Chandrayaan-1, Chang'E 1, the US Lunar Reconnaissance Orbiter, the LCROSS impact, future lunar landers and upcoming missions, and to contribute towards objectives of the Moon Village and future exploration.

Dissolved free amino acids (DFAA) in seawater are a form of nitrogen (N) available for marine microbes. In oligotrophic environments where N-containing nutrients are the limiting factor for microbial growth, N nutrition from DFAA could be crucial, but as yet it is poorly resolved. Measurements of individual DFAA are challenging as concentrations are typically in the low nmol L − 1 range. Here we report modifications to methodology using o-phthaldialdehyde (OPA) derivatization and reversed phase high performance liquid chromatography (HPLC) that provide a 30-fold improvement in sensitivity enabling the detection of 15 amino acids in seawater with a limit of detection as low as 10 pmol L − 1 with accuracy and precision of better than 10%. This analytical methodology is now suitable for the challenging quantitation of DFAA in oligotrophic seawaters. The method was successfully applied to a suite of seawater samples collected on a cruise crossing the South Atlantic Ocean, where concentrations of DFAAs were generally low (sub nmol L − 1 ), revealing basin-scale features in the oceanographic distributions of DFAA. This unique dataset implies that DFAAs are an important component of the N cycle in both near-coastal and open oceans. Further calculations suggest that the proportions of organic N originating from DFAA sources were significant, contributing between 0.2 and 200% that of NH 4 + and up to 77% that of total inorganic nitrogen in the upper 400 m in some regions of the transect.

Availability of iron limits productivity in the Southern Ocean where vast regions of high-nitrogen low-chlorophyll conditions are punctuated by hotspots of production surrounding the subAntarctic islands. Here, we compare patterns in accumulation of iron, as indicated by [Fe] and Fe : C (from Wing et al. 2014), with proxies for uptake of iron within food webs, as indicated by Fe : Al and δ56Fe within the subAntarctic Auckland Island ecosystem. We compare these proxies for dynamics of iron within egested material collected from six seabird species, representing three distinct foraging guilds. Fractions of biogenic iron, estimated from Fe : Al, were lowest in the coastal foraging guild (0.83 ± 0.01), and higher in the oceanic and predator guilds (0.94 ± 0.01 and 0.95 ± 0.01), consistent with high rates of biological recycling. The isotopic ratio of iron 56Fe/54Fe, reported as δ56Fe, is depleted in the heavy isotope 56Fe by recycling in the microbial loop, and is likely further depleted in 56Fe when taken up by animals within the food web. δ56Fe was most negative for the oceanic foraging group indicating intensive recycling (−1.16 ± 0.16‰), most positive in the coastal group where direct lithogenic sources of iron are more available (−0.14 ± 0.15‰), and intermediate in the predatory group, representing a mixture and possible fractionation within food webs (−0.37 ± 0.14‰). These data reveal strong contrasts in bioaccumulation and recycling of iron between coastal and oceanic food webs, and important interactions between marine food web structure and biogeochemical processes supporting productivity in the Southern Ocean.

An untargeted metabolomics approach was applied for the discrimination of honey of various floral and geographical origins using ultra-performance liquid chromatography-quadrupole time of flight mass spectrometry (UPLC-QToF MS). Evaluation of data by multivariate data analysis allowed the discrimination of New Zealand and Australian honeys from honeys originating in other countries. It was also possible to differentiate between mono- and polyfloral honeys within one region, as well as between some monofloral honeys of various geographical origins. Characteristic markers, contributing to the segregation of different honey types, were selected and characterized.

In this investigation, two previously reported precipitation δ2H isoscapes for New Zealand were used to develop a δ2H isoscape for blackberry (Rubus sp.) leaf. These isoscapes were calibrated using the measured δ2H values of 120 authentic blackberry leaf samples collected from across the country. A regression model based on environmental variables available for New Zealand was also determined to predict δ2H values measured from blackberry leaves without initially modelling the precipitation δ2H values. The three models were compared for their accuracy and precision when assigning 10 samples of blackberry leaves for their geographic location based on their measured δ2H values. One of the models based on a precipitation isoscape was similar in accuracy and precision of assignment to the model determined from the environmental variables and provides an approach for determining valid isoscapes for future plant materials.

Hydrogen and oxygen isotope ratios are of use to determine the origin of matter. Thermolysis is used to convert matter to H2 and CO gases, which are the respective substrates for measurement of these two isotope ratios, using isotope ratio mass spectrometry (IRMS). This work was done in response to the need for analysis of small invasive insects, requiring a decrease in the limit of measurement for isotope ratiometry of hydrogen and oxygen, while determining both isotope ratios on the same sample. Miniaturization of a thermolysis reactor using commercially available components is presented that results in improvement in the limit of measurement for both hydrogen and oxygen isotope ratios. δ2H was determined on 0.4 μg of H and δ18O determined on 5 μg of O with precisions of 3 mUr and 0.7 mUr, respectively. To extend the usable sample size range or increase the resolution of sampling gives obvious advantages in forensic and environmental sciences. The technique has been applied to determining the natural origin of Tephritidae fruit flies for which only the wing is suitable for analysis and provides just 60 μg of material for analysis.

This study is the first to investigate the evolution of cow milk metabolites throughout the vat pasteurization process and storage using untargeted metabolomics based on a multiplatform approach. Nuclear magnetic resonance and ultraperformance liquid chromatography-quadrupole time-of-flight mass spectrometry were used for fingerprinting water-soluble nutritional compounds, and headspace gas chromatography-mass spectrometry was used to fingerprint the volatile organic compounds. This study demonstrated that vat pasteurization was an efficient and mild means of milk preservation resulting in only minor changes to the metabolites. The pasteurized milk samples exhibited a stable metabolome during the first 8 d of refrigerated storage. However, at the latter stage of storage, the concentrations of pantothenic acid and butyrylcarnitine decreased, whereas some fatty acids, organic acids, α-AA, peptides, and ketones increased. These selected metabolites that changed during milk storage could be used as potential biomarkers to track the storage conditions of pasteurized cow milk.

BACKGROUND Post‐border detection of a single brown marmorated stink bug (BMSB) in New Zealand warranted a biosecurity response, the nature of which would be influenced by its status as part of an established population or as a new arrival. Stable isotope analysis has the potential to determine natal origins, but is difficult to achieve for samples as small as a single insect. Here an analytical modification to measure small samples was successfully trialled as a means to supply evidence as to the local or exotic natal origin of the intercepted BMSB specimen. RESULTS Sufficient analytical sensitivity was achieved using a modified isotope ratio mass spectrometry method, involving thermolysis and carbon monoxide cryofocusing, to enable the simultaneous analysis of δ2H and δ18O from wings of the post‐border BMSB sample. The values were much lower than those of the New Zealand green vegetable bug, used as a local reference. However, they fell within the range of those for BMSB of Northern Hemisphere origin intercepted at the New Zealand border over the same time period, specifically overlapping with the USA and Italy, but not China. CONCLUSION The isotope signature of the post‐border detected BMSB suggested a significantly cooler climate than the North Island of New Zealand, indicating that it was a new arrival and did not represent an established population. © 2019 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry., Provenance determination of pest insects can improve biosecurity and pest‐management outcomes. Here, a brown marmorated stink bug incursion of unknown origin is investigated using δ2H and δ18O, enabled by a modified analytical method.

Characterizing the spatial distribution of δ18O in seawater and δ15N and δ13C in marine particulate organic matter pools can be useful in identifying isotopic discriminators of major water masses and serve as a baseline for food web and other ecological studies. Nevertheless, we do not know how isoscapes of δ18O, δ15N and δ13C are distributed and interact with mesoscale (10–100 km) physical oceanographic features for large parts of the global ocean. Here samples and measurements were collected during research cruises in the austral summer of 2017/18 and 2018/19 along the east coast of the South Island of New Zealand. The physical structure of the water column, δ18O of seawater, and δ15N and δ13C of suspended particulate organic matter were analyzed. Interannual differences in inferred circulation, oceanographic features, and the interaction of Subtropical and Subantarctic water masses in the study area were described. The relationships between nutrient concentrations, physical oceanographic variables and δ18O, δ15N and δ13C isoscapes were investigated by running linear models with all combination of variables, then averaging the most parsimonious ones that best fit the data. Results demonstrate that different environments along the east coast are connected via northward transport of Subtropical Water near the surface and Subantarctic Mode Water at depth (220–500 m). The northward transport of modified STW was associated with nutrient inputs and deepening of the maximum fluorescence depth. The spatial distribution of isotopic values had minimal temporal variability and was primarily linked to patterns of nutrient input (δ15N), coastal productivity (δ13C) and water mass type (δ18O). δ15N values demonstrated significant spatial variation, while δ18O displayed distinct values among depths. The present study was the first to resolve the distribution of δ15N and δ13C isotopes at a regional scale along the east coast of the South Island of New Zealand, δ18O in New Zealand waters, and to investigate the extent to which these distributions were influenced by patterns in physical oceanography. Average values of δ18O, δ15N and δ13C for different fishery management areas and depths are presented to support future ecological studies along Southeast New Zealand.

Background: Milk is an important food component in the human diet and is a target for fraud, including many unsafe practices. For example, the unscrupulous adulteration of soymilk into bovine and goat milk or of bovine milk into goat milk in order to gain profit without declaration is a health risk, as the adulterant source and sanitary history are unknown. A robust and fit-for-purpose technique is required to enforce market surveillance and hence protect consumer health. Nuclear magnetic resonance (NMR) is a powerful technique for characterization of food products based on measuring the profile of metabolites. In this study, 1D NMR in conjunction with multivariate chemometrics as well as 2D NMR was applied to differentiate milk types and to identify milk adulteration.; Results: Ten metabolites were found which differed among milk types, hence providing characteristic markers for identifying the milk. These metabolites were used to establish mathematical models for milk type differentiation. The limit of quantification (LOQ) of adulteration was 2% (v/v) for soymilk in bovine milk, 2% (v/v) for soymilk in goat milk and 5% (v/v) for bovine milk in goat milk, with relative standard deviation (RSD) less than 10%, which can meet the needs of daily inspection.; Conclusion: The NMR method described here is effective for milk authenticity identification, and the study demonstrates that the NMR-based milk metabolite analysis approach provides a means of detecting adulteration at expected levels and can be used for dairy quality monitoring. © 2016 Society of Chemical Industry.; © 2016 Society of Chemical Industry.

Nonprotein nitrogen compounds may be added to milk by unscrupulous producers to boost the apparent protein concentration. These compounds are nephrotoxic and may cause urinary disease. Nuclear magnetic resonance (NMR) was used for the simultaneous determination of urea, melamine, guanidine, biuret, and diaminoguanidine in milk. The nitrogen-containing compounds were accurately quantified with recoveries between 80 and 110% with relative standard deviations less than 6%. The limit of quantitation was 2.0 mg/L for melamine and urea; 8.0 mg/L for guanidine, biuret, and diaminoguanidine. The urea in milk was quantified by NMR, and the concentration varied with the production region. However, the level did not exceed the maximum safe level of 620 mg/L.

Carbon and nitrogen stable isotope ratios of amino acids (δ13CAA and δ15NAA) have been recently used to unravel trophic relationships in aquatic and terrestrial environments. However, none have studied the specific case of a symbiotic relationship. Here we use the stable isotope ratios of amino acids (AAs) to investigate the link between a scarab larva (Pericoptustruncatus) and its mite guest (Mumulaelaps, Mesostigmata: Laelapidae: Hypoaspidini). Five scenarios for the relationship between larva and mite were proposed and δ13CAA and δ15NAA respective data and patterns helped eliminate those that were inconsistent. The calculated gap of two trophic levels ruled out a parasitic trophic relationship scenario. The trophic relationship between P. truncatus was shown to most likely be commensalistic with the mites feeding on the larva's castings. Alongside this study, a comparison with the stable isotope bulk analysis method was made and demonstrated that the AA method brings a significant refinement to the results by providing a means of determining absolute tropic level without the need for prior knowledge of the isotopic composition of primary source material.

The abundances of low-molecular-weight metabolites in milk have been known to change during the lactation stage, and this is of relevance to the milk nutritional or processing properties. Metabolomics was used to investigate changes in 46 milk samples from 19 Jersey cows. Metabolites were measured using both nuclear magnetic resonance and mass spectrometry based methods. Metabolites exhibiting change were identified with the aid of multivariate and univariate data analysis. The changing metabolites included amino acids and derivatives (taurine, purine, indoleacetic acid, aminoadipic acid), organic acids (uric acid, hippuric acid, citric acid), carbohydrates (N-acetyl- d -glucosamine, galactose-1-phosphate), vitamins (choline and pantothenic acid), nucleic acid-related compounds (cytosine, uracil and methylguanine) and fatty acids (lauric acid). This research not only provides a full understanding of the milk metabolomic changes due to the cow lactation stage but also can be used as the foundation for marker selection for further studies utilising milk metabolomics.

This study is the first to investigate the effect of freeze-drying on raw milk metabolites using untargeted metabolomics. To detect as many metabolites as possible in the liquid fractions, a multiplatform metabolomics approach was implemented using both NMR and MS-based techniques. The chemical fingerprint of freeze-dried milk powder was monitored during storage at three temperatures (room temperature, 4 °C, −20 °C) for up to 224 days. This study demonstrated that freeze-drying was an efficient means of drying milk resulting in only minor changes to the metabolites. With respect to storage, freeze-dried milk powders stored at 4 °C and −20 °C exhibited a stable metabolome while samples stored at 20 °C resulted in a clear change. During ambient storage, the concentrations of orotic acid, riboflavin and acetyl-carbohydrate reduced while those of fatty acids, threonic acid and uridine increased. The results from this study provide the foundation for experiment design and marker selection for further studies on milk metabolomics.

The global distribution of dissolved cadmium (Cd) in the world’s oceans is generally well understood. However, information on seasonal variability of this and other trace metals in the open ocean is difficult to obtain and, therefore, our understanding is limited. Here, we present a 3-year time series of field measurements of dissolved and particulate Cd and phosphate (PO4) from a transect across the subtropical convergence, south-eastern New Zealand. In the final year of study, the bioactive trace metals (iron, Fe; zinc, Zn; cobalt, Co) and nutrients (nitrate, NO3; silicate, Si(OH)4) were also measured to identify their influence on Cd cycling in the region. Cadmium varied seasonally from 0.009 to 0.137nM in the sub-Antarctic surface waters (SASW). Zinc in SASW varied between 0.03 and 0.011nM, which is low enough to suggest Zn limitation year-round. The seasonal input of dissolved Fe may stimulate phytoplankton growth in summer where microplankton (especially diatoms) dominate the phytoplankton distribution. The Cd:PO4 ratio also varied strongly with season (0.015×10–3 to 0.05×10–3). This seasonal variation in the Cd:PO4 ratio is productivity driven as revealed in the characteristic trend in the Cd:PO4 ratio, particulate Cd and chlorophyll-a measurements. The high seasonal variability between Cd and PO4 complicates the application of the Cd proxy for the reconstruction of historical PO4 concentrations in SASW.

Rationale Stable isotope ratios can provide a 'fingerprint' to enable differentiation of sources of monofluoroacetate (MFA), hence providing a means to eliminate potential sources of MFA in a blackmail case involving the contamination of milk. Methods The stable isotopic compositions (δ2 H, δ13 C and δ18 O values) of a library of 43 samples of MFA were determined and multivariate models constructed to differentiate samples of different composition. The data from the MFA library were compared with those obtained from MFA extracted from contaminated milk powder (the case samples). The isotopic composition of the extracted samples was measured on dichloroaniline derivatives. Results A wide range of values was found for δ2 H, δ13 C and δ18 O of the MFA samples, much greater than the analytical repeatability between subsamples. Stable isotope data, therefore, provide a means of distinguishing samples of MFA. Of the 43 MFA samples tested, all but 6 could be eliminated as potential sources of the contamination, i.e. they had a distinctly different isotopic composition such that they must have had different histories and/or origins. Conclusions Stable isotope measurements of bulk and derivatized MFA provide an effective means of discriminating MFA samples. Three of the library samples that could not be differentiated from the case samples were directly connected to the suspect, and this evidence contributed to the suspect's admission of guilt.

The ExoMars Trace Gas Orbiter (TGO) Science Ground Segment (SGS), comprised of payload Instrument Team, ESA and Russian operational centres, is responsible for planning the science operations of the TGO mission and for the generation and archiving of the scientific data products to levels meeting the scientific aims and criteria specified by the ESA Project Scientist as advised by the Science Working Team (SWT). The ExoMars SGS builds extensively upon tools and experience acquired through earlier ESA planetary missions like Mars and Venus Express, and Rosetta, but also is breaking ground in various respects toward the science operations of future missions like BepiColombo or JUICE. A productive interaction with the Russian partners in the mission facilitates broad and effective collaboration. This paper describes the global organisation and operation of the SGS, with reference to its principal systems, interfaces and operational processes.

Honey is a high value food commodity with recognized nutraceutical properties. A primary driver of the value of honey is its floral origin. The feasibility of applying multivariate data analysis to various chemical parameters for the discrimination of honeys was explored. This approach was applied to four authentic honeys with different floral origins (rata, kamahi, clover and manuka) obtained from producers in New Zealand. Results from elemental profiling, stable isotope analysis, metabolomics (UPLC-QToF MS), and NIR, FT-IR, and Raman spectroscopic fingerprinting were analyzed. Orthogonal partial least square discriminant analysis (OPLS-DA) was used to determine which technique or combination of techniques provided the best classification and prediction abilities. Good prediction values were achieved using metabolite data (for all four honeys, Q(2)=0.52; for manuka and clover, Q(2)=0.76) and the trace element/isotopic data (for manuka and clover, Q(2)=0.65), while the other chemical parameters showed promise when combined (for manuka and clover, Q(2)=0.43).

Traceability of dairy products is an important issue for the dairy industry. Empirical studies have demonstrated the utility of stable isotope measurements on milk for verification of origin. However, various drivers influence the isotopic composition of a food stuff, such as rainfall levels or food supplements. Relationships between the isotopic composition (δ2H, δ18O, δ13C and δ15N) of milk fatty acids, the water component of the milk, and feed and farm water from 18 New Zealand dairy farms were studied. Significant relationships between the isotopic composition of milk and both farm water and feed fatty acids were observed. Measurement of both diet and drinking water from each dairy farm enabled the underlying environmental correlations to milk fatty acids to be explored by analysis of their respective δ2H values. Development of this technology may provide a diagnostic tool for determining type and the origin of dietary feed utilised in milk production.

Alterations to ecosystem nitrogen (N) cycling by introduced plant species may increase the invasibility of habitat providing a positive feedback for the introduced species to become invasive. Spatial patterns of foliar and soil δ15N ratios reflect variation in rates and process of N-cycling across invaded landscapes and provide insight into N-source uptake and utilization strategies of invasive plant species. To evaluate invasion-associated changes in soil and foliar δ15N at different scales: regional (among different sites), local (between north- and south-facing aspect at the same site), and microsite (within populations in the same community), we measured foliar and soil δ15 N, animal faeces cover (as a proxy for grazing intensity) and N2-fixing species cover from inside to outside Thymus vulgaris L. (thyme)-invaded lightly grazed pastoral communities in Central Otago, southern South Island, New Zealand. Mean thyme foliar δ15N were near-zero across the invaded landscape, and did not change across the advancing edge of invasion or with aspect. There was no evidence that associations with N2-fixing species provide a potential N source. Soil δ15N was lower inside of thyme compared to at the edge or outside of thyme and was varied between aspects at some sites. Animal faeces cover as a proxy for grazing intensity explained only 23% of this observed variation of soil δ15N. Thyme invasion may result in lowered soil δ15N reflecting alterations to N dynamics. Associated invasion-related impacts of animal grazing may also impact soil δ15N. Further studies are required to distinguish the underlying mechanism responsible for the observed patterns of foliar and soil δ15N values across thyme-invaded Central Otago landscapes.

Here we present the longest time series of iron speciation along a coastal shelf area. A time series of a surface transect across the Otago Continental Shelf and into the high-nutrient low-chlorophyll (HNLC) Subantarctic surface water (SAW) was undertaken between 2000 and 2008 to measure the dissolved iron (DFe) concentration, organic iron-complexation parameters, as well as macronutrient concentrations and general hydrographic data. The study area contains three distinct water types: 1) neritic water; 2) modified subtropical water (STW); and 3) Subantarctic surface water (SAW). Variations in nutrient concentrations in the study area indicated that SAW is the predominant source of nitrate and phosphate to the shelf. Dissolved iron (DFe) concentrations dropped seawards from several nanomolar to sub-nanomolar levels. The dissolved iron was fully complexed with strong organic ligands (L1) in all three water types, and the ligand concentrations decreased seawards. However the ratio between [L1]/[DFe], a measure of the ligand saturation, increased from

Understanding the influence of spatial scale on ecological processes that occur with exotic plant invasion can help us identify underlying mechanisms of successful invasion. Here we studied spatial associations between Thymus vulgaris invasion and plant community species richness, composition and abundance at multiple spatial scales. These scales included among-sites, differences between aspects at the same site, and differences that occur between the inside, edge and outside of thyme stands at the same site. We examined how aspect (north or south) and site location influence spatial distribution patterns of thyme (cover and canopy height). We also quantified the relationship between variability in plant community composition inside, at the edge and outside of thyme-invaded communities and soil physical and chemical properties, cover of animal faeces, bare ground and schist, altitude and slope. We found lower species richness inside thyme-dominated communities, and this change was often greater on the north-facing slopes than the south-facing slopes. Plant species and plant functional groups had individualistic abundance patterns associated with thyme’s invasion. Exotic grasses, exotic forbs and native shrubs showed significant decreases in cover inside thyme stands, but native forb and native grass abundances were not significantly affected by thyme’s presence. Thyme density varied with aspect at some sites, generally being less dense on the south-facing slopes compared to the north-facing slopes. A subset of 15 environmental variables explained 54 % of plant assemblage variation inside, at the edge and outside of thyme-invaded communities, highlighting the important influence of site differences on invaded plant community assemblages.

Biological vectors are important for redistribution of nutrients in many ecological systems. While availability of iron (Fe) to phytoplankton limits pelagic productivity in the Southern Ocean, biomagnification within marine food webs can lead to high concentrations of Fe in the diet of seabirds and marine mammals. We investigated patterns in concentrations of the micronutrients Fe, Co, Zn and Mn, and the toxins Cd and As, in the guano of oceanic, coastal and predatory seabirds and in faeces of 2 species of marine mammals that congregate to breed in the sub-Antarctic Auckland Islands. We found that much of the variability in concentrations of Fe, Co, Zn and Mn among species could be explained by foraging behaviour and by trophic position. We observed concentrations of Fe to be 8 orders of magnitude higher in the guano of predators and coastal foragers than in the sub-Antarctic mixed layer. High concentrations of As and Cd were associated with organic matter sources from macroalgae. Analyses of the molar ratio Fe:Al indicated that Fe within food webs supporting seabirds has likely been extensively recycled from its lithogenic source. Patterns in Fe:N among species indicated that Fe is concentrated 2 to 4 orders of magnitude in the guano of seabirds compared to limiting conditions for phytoplankton growth in sub-Antarctic waters. These data highlight the potential role of seabirds and marine mammals in the redistribution of micronutrients in the Southern Ocean and their likely role as key nutrient vectors in the ecosystem, particularly around the sub-Antarctic islands during the breeding season.

The aim of this research was to increase the understanding of how exotic plant invasion can alter abiotic and biotic soil properties across multiple sites encompassing the geographic distribution of the study species, between aspects at each site, and across the edge of invasion. Our research questions were: do soil physicochemical properties and soil bacterial community structure inside thyme-dominated communities differ from those at the edge and outside of thyme-invaded plant communities? We compared pH, soil moisture, C, N, P, NO 3 − , NH 4 + , soil particle size and soil bacterial ribotype DGGE profiles directly inside, at the edge and outside of north- and south-facing thyme stands across semi-arid areas of Central Otago. Among the soil physicochemical factors investigated organic P was significantly lower inside thyme-invaded plant communities. Thyme's invasion had a significant correlation with increased sand content and decreased soil moisture. We did not detect any variation in soil bacterial diversity from inside to outside thyme-invaded communities. While it appears that there are significant associations between thyme invasion and soil texture, site differences appear to be the major drivers of variation in soil physicochemical properties and soil bacterial diversity.

Compound-specific isotope analysis offers potential for fingerprinting of diesel fuels, however, possible confounding effects of isotopic fractionation due to evaporation need to be assessed. This study measured the fractionation of the stable carbon and hydrogen isotopes in n-alkane compounds in neat diesel fuel during evaporation. Isotope ratios were measured using a continuous flow gas chromatograph/isotope ratio mass spectrometer. Diesel samples were progressively evaporated at 24 ± 2°C for 21 days. Increasing depletion of deuterium in nC12-nC17 alkanes in the remaining liquid with increasing carbon chain length was observed. Negligible carbon isotope fractionation was observed. Preferential vaporization was measured for the shorter chain n-alkanes and the trend decreased with increasing chain length. The decrease in δ(2) H values indicates the preferential vaporization of the isotopically heavier species consistent with available quantitative data for hydrocarbons. These results are most important in the application of stable isotope technology to forensic analysis of diesel.

Saffron, the dried red stigmas of Crocus sativus L. is the world's most expensive spice. The expense of Saffron has led to greater incidences of fraudulent practice within this market. The importation and rebranding of cheaper growing regions to be passed off as regions of higher quality is one such practice. Analytical techniques have been reported in literature for rapid detection of these fraud issues. These techniques can be affected by post harvest processing, therefore more confirmatory techniques with direct links to the environment should also be considered. Trace element concentrations and stable isotopic ratios are investigated in this study to differentiate the geographic origins of Saffron grown in Khorasan Province, Iran and the La Mancha region of Spain. Statistical analysis of the data using Linear Discriminate Analysis (LDA) resulted in a classification model which could determine saffron from each origin, suggesting this is a feasible confirmatory approach for origin verification of Saffron.