Composite Fingerprints Research Articles

1H NMR metabolite fingerprinting and metabolomic analysis of perchloric acid extracts from plant tissues

Metabolite fingerprinting provides a powerful method for discriminating between biological samples on the basis of differences in metabolism caused by such factors as growth conditions, developmental stage or genotype. This protocol describes a technique for acquiring metabolite fingerprints from samples of plant origin. The preferred method involves freezing the tissue rapidly to stop metabolism, extracting soluble metabolites using perchloric acid (HClO4) and then obtaining a fingerprint of the metabolic composition of the sample using 1D 1H NMR spectroscopy. The spectral fingerprints of multiple samples may be analyzed using either unsupervised or supervised multivariate statistical methods, and these approaches are illustrated with data obtained from the developing seeds of two genotypes of sunflower (Helianthus annuus). Preparation of plant extracts for analysis takes 2-3 d, but multiple samples can be processed in parallel and subsequent acquisition of NMR spectra takes approximately 30 min per sample, allowing 24-48 samples to be analyzed in a week.

Physical insights from a penetration depth model of optically pumped NMR

A model of optically pumped NMR (OPNMR) behavior in GaAs that connects the photon energy dependence of the OPNMR signal intensity for (69)Ga with different polarizations of light has been developed. Inputs to this model include experimental conditions--external magnetic field (B(0)), temperature (T), and optical pumping parameters (tau(L), laser helicity)--as well as parameters that arise from sample-specific characteristics--electron spin lifetime (T(1e)), electron lifetime (tau(e)), electron-nuclear correlation time (tau(c)), and sample thickness (z). These various inputs affect the profile of the OPNMR signal intensity as a function of photon energy (E) in a predictable manner. Therefore, the profile can serve as a composite fingerprint by which individual parameters can be inferred when not known. Characteristics of the profile include the photon energy for maximum OPNMR signal intensity and the intensity ratio between sigma(+) and sigma(-) light.

Fingerprints and age models for widespread New Zealand tephra marker beds erupted since 30,000 years ago: a framework for NZ-INTIMATE

The role of tephras in the NZ-INTIMATE project is a critical one because most high-resolution palaeoclimatic records are linked and dated by one or more tephra layers. In this review, first we document eruptive, distributional, and compositional fingerprinting data, both mineralogical and geochemical, for 22 key marker tephras erupted since 30,000 years ago to facilitate their identification and correlation. We include new glass compositional data. The selected marker tephras comprise 10 from Taupo and nine from Okataina volcanoes (rhyolitic), one from Tuhua volcano (peralkaline rhyolitic), and one each from Tongariro and Egmont volcanoes (andesitic). Second, we use four approaches to develop 2 σ-age models for the tephras (youngest to oldest): (1) calendar ages for Kaharoa and Taupo/Y were obtained by wiggle-matching log-derived tree-ring sequences dated by 14C; (2) Whakaipo/V was dated using an age–depth model from peat; (3) 14 tephras in the montane Kaipo peat sequence (Waimihia/S, Unit K, Whakatane, Tuhua, Mamaku, Rotoma, Opepe/E, Poronui/C, Karapiti/B, Okupata, Konini, Waiohau, Rotorua, Rerewhakaaitu) were dated by simultaneously wiggle-matching stratigraphic position and 51 independent 14C-age points against IntCal04 using Bayesian probability methods via both OxCal and Bpeat; and (4) the five oldest tephras, erupted before ca 18,000 cal. yr BP, were dated by calibrating limited numbers of 14C ages using IntCal04 (Okareka) or comparison curves of the expanded Cariaco Basin sequence (Te Rere, Kawakawa/Oruanui, Poihipi, Okaia). Kawakawa/Oruanui tephra, the most widely distributed marker tephra, was erupted probably ca 27,097±957 cal. yr BP. Potential dating approaches for the older tephras include their identification in Antarctic ice cores (if present) or annually laminated sediments for which robust calendar-age models have been constructed, high-precision AMS 14C dating on appropriate material from environmentally stable sites, systematic luminescence dating, or new radiometric techniques (e.g. U–Th/He) if suitable minerals are available and errors markedly reduced. Further application of Bayesian age-modelling to stratigraphic sequences of 14C ages, possibly augmented with luminescence ages, may help refine age models for pre-Holocene tephras with the largest errors. Finally, we discuss the critical role these marker tephras play in the ongoing construction of an event stratigraphy for the New Zealand region, which is a key objective of Australasian and Southern Hemisphere INTIMATE projects.

Sources of fine sediment recovered from the channel bed of lowland groundwater-fed catchments in the UK

Groundwater-fed, lowland permeable catchments in the UK are particularly susceptible to fine sediment accumulation on the bed of their main channel systems. Appropriate catchment management solutions are therefore required. Accurate targeting of sediment abatement strategies is, however, hampered by the dearth of reliable information on the principal sediment sources involved. In view of this, a composite fingerprinting technique, incorporating uncertainty analysis, has been used to investigate the primary sources of fine sediment samples recovered from a total of 18 individual sampling sites on the channel bed of the rivers Frome (∼ 437 km 2) and Piddle (∼ 183 km 2), Dorset, UK. In the Frome study catchment, mean relative contributions from areas of woodland, pasture and cultivation, and from channel banks/subsurface sources ranged between 1 ± 1%–6 ± 2%, 10 ± 2%–42 ± 2%, 44 ± 4%–81 ± 2% and 7 ± 2%–19 ± 4%, respectively. The corresponding mean relative contributions in the Piddle study area were 1 ± 1%–11 ± 4% (woodland), 10 ± 2%–28 ± 4% (pasture), 44 ± 2%–80 ± 2% (cultivated) and 7 ± 2%–21 ± 2% (channel banks and subsurface sources). These findings have important implications for establishing a scientific basis for assisting the targeting of sediment management and control policies.

Spectroscopy of Growing and Evaporating Water Droplets: Exploring the Variation in Equilibrium Droplet Size with Relative Humidity

We demonstrate that the thermodynamic properties of a single liquid aerosol droplet can be explored through the combination of a single-beam gradient force optical trap with Raman spectroscopy. A single aqueous droplet, 2-6 microm in radius, can be trapped in air indefinitely and the response of the particle to variations in relative humidity investigated. The Raman spectrum provides a unique fingerprint of droplet composition, temperature, and size. Spontaneous Raman scattering is shown to be consistent with that from a bulk phase sample, with the shape of the OH stretching band dependent on the concentration of sodium chloride in the aqueous phase and on the polarization of the scattered light. Stimulated Raman scattering at wavelengths commensurate with whispering gallery modes is demonstrated to provide a method for determining the size of the trapped droplet with nanometer precision and with a time resolution of 1 s. The polarization dependence of the stimulated scatter is consistent with the dependence observed for the spontaneous scatter from the droplet. By characterizing the spontaneous and stimulated Raman scattering from the droplet, we demonstrate that it is possible to measure the equilibrium size and composition of an aqueous droplet with variation in relative humidity. For this benchmark study we investigate the variation in equilibrium size with relative humidity for a simple binary sodium chloride/aqueous aerosol, a typical representative inorganic/aqueous aerosol that has been studied extensively in the literature. The measured equilibrium sizes are shown to be in excellent agreement with the predictions of Köhler theory. We suggest that this approach could provide an important new strategy for characterizing the thermodynamic properties and kinetics of transformation of aerosol particles.

The effect of sample size in studies of soil microbial community structure

Replicate soil samples of 0.01, 0.1, 0.25, 1.0 and 10.0 g were taken from a single, large, homogenized sample from a field maintained as continuous meadow. The samples were processed for direct enumeration of bacterial cells and community structure assays by DGGE analysis of PCR-amplified 16S-rDNA fragments from whole community extracts. The goal was to determine the sample size or size range that produced the most consistent results (i.e., mean values) and the lowest variance. Enumeration data were analyzed by ANOVA, and the community composition fingerprints were analyzed by discriminant analysis (DA). Acceptable results were obtained for sample sizes from 0.1 to 1.0 g for both enumeration and community fingerprinting, but the size that yielded the best results for both measures was 0.25 g. The results suggest that for well homogenized silt loam soils with moderate organic matter concentrations, this sample size should produce high quality consistent results. For soils that differ in organic concentrations or clay content, a reconnaissance survey similar to the present examination is recommended.

Organic Carbon Composition and Oxygen Metabolism across a Gradient of Seasonally Inundated Limesink and Riparian Wetlands in the Southeast Coastal Plain, USA

A set of three relatively pristine seasonally inundated limesink wetlands and one riparian wetland was studied over a 4–6 month long inundation period in 2001. Patterns in organic matter properties and oxygen consumption in the water column followed a previously documented ecological gradient based on soil composition, vegetation type, and canopy cover. The full canopy, cypress-gum swamp had the highest mean concentrations of dissolved organic carbon (DOC; 26.2 mg/l) and dissolved lignin (sum 6; 299 μg/l) with lower concentrations observed in the partial canopy, cypress savanna (22.0 mg/l DOC; 252 μg/l sum 6) and the open marsh savanna (20.6 mg/l DOC; 135 μg/l sum 6), respectively. During the inundation period, DOC increased in concentration, dissolved lignin decreased, and δ13C shifted to more positive values which collectively indicate a large reduction in the percentage of aromatic carbon during the inundation period. All wetlands had very high concentrations of organic matter, yet microbial oxygen consumption was almost always stimulated by the addition of glucose rather than inorganic nutrients. Stimulation by glucose suggests that there were very small pools of highly bioavailable forms of DOC in the wetlands. A larger pool of moderately bioavailable organic matter had the capacity to sustain microbial oxygen consumption rates under dark conditions for at least 15 d. During the inundation period, the cypress-gum swamp had the lowest average rates of whole water oxygen consumption (1.0 μM/h) with increasing rates observed in the cypress savanna (1.3 μM/h), marsh savanna (1.6 μM/h), and riparian wetland (1.9 μM/h), respectively. The lignin compositional fingerprint varied across the gradient of limesink wetlands, and was useful for identifying different sources of vascular plant-derived DOM. Vascular plant production, algal production, microbial respiration, and UV degradation are all important drivers of DOM cycling, and the consistencies observed in this initial assessment of seasonally inundated limesink wetlands suggest they vary in predictable ways across the ecological gradient.

Obsidian provenance studies in archaeology: A comparison between PIXE, ICP-AES and ICP-MS

Elemental composition fingerprinting by PIXE technique is very attractive for obsidian provenance studies as it may proceed in a non-destructive mode, even if a more complete elemental characterization can be obtained by ICP-MS and/or ICP-AES. Only few studies have compared results obtained by both methods for solid rock samples. In this work, elemental compositions were determined by ICP-MS/-AES for international geochemical standards and by ICP-MS/-AES and PIXE for inter-laboratory reference obsidians. In addition 49 obsidian source samples and artefacts were analysed by both ICP-MS/-AES and PIXE. Instrumental work and measurement quality control performed for obsidian chemical characterization, underline that PIXE and ICP-MS/-AES provide reproducible, accurate and comparable measurements. In some volcanic districts the limited number of elements dosed by PIXE is sufficient for the discrimination of the potential raw sources of obsidians. Therefore, PIXE can be an advantageous substitute to ICP-MS/-AES techniques for provenance studies.

Screening and sequencing of complex sialylated and sulfated glycosphingolipid mixtures by negative ion electrospray Fourier transform ion cyclotron resonance mass spectrometry

A protocol for negative ion nanoelectrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (-)nanoESI-FTICR MS, investigation of complex biological mixtures consisting of sialylated or sulfated glycosphingolipids (GSL) expressing high heterogeneity in the ceramide portion is described. Different instrumental and solvent conditions were explored and optimized to promote efficient ionization, reduce the in-source fragmentation and consequently enhance the detection of intact molecular species from complex mixtures. Using the novel optimized (-)nanoESI-FTICR MS protocol, a reliable and detailed compositional fingerprint of the polysialylated ganglioside mixture isolated from human brain was obtained. Sustained off-resonance irradiation collision-induced dissociation mass spectrometry (SORI-CID MS2) was introduced for the first time for structural elucidation of polysialylated gangliosides. Under well-defined conditions, an informative fragmentation pattern of the trisialylated ganglioside GT1 was obtained. The compositional mapping of a complex mixture of sulfated glucuronic acid containing neolacto-series GSLs extracted from bovine Cauda equina provided hard evidence upon previously described components and new structures not identified before by any other analytical method. Negative ion nanoESI-FTICR MS at 9.4 T is shown here to represent a valuable method in glycolipidomics, allowing a high resolution and mass accuracy detection of major and minor GSL glycoforms and identification of known and novel biologically relevant structures.

X-ray Fluorescence Analysis of Iron Gall Inks, Pencils and Coloured Crayons

The qualitative and quantitative investigation of historical writing materials using micro X-ray fluorescence analysis (micro-XRF) is a suitable method for obtaining ‘composition fingerprints’ of different inks and coloured crayons. The quantitative analysis is based on a model that takes into account the heterogeneity and the layer structure of historical samples. Starting from these composition fingerprints, it is possible to distinguish between different iron gall inks used by an individual artist in order to establish a chronology of their use and, furthermore, to date unknown fragments that have not been integrated into the oeuvre of an artist until now. Qualitative and quantitative analyses of several manuscripts of Johann Wolfgang von Goethe clarify the chronology within the genesis of these works. Investigation of Achim von Arnim's manuscript ‘Studien zu Naturwissenschaften’ indicated that various degradation mechanisms of iron gall inks could also be related to different inorganic compositions. Further measurements on coloured crayons in Friedrich Nietzsche's notebooks reveal that it is possible to distinguish between different notes written by Nietzsche and his successors. Finally the analyses of two different pencils from Goethe's work shows that it might be possible to distinguish between sketches completed before and after 1800.

Characterization of vegetable oils: detailed compositional fingerprints derived from electrospray ionization fourier transform ion cyclotron resonance mass spectrometry.

Adulteration of vegetable oil is of concern for both commercial and health reasons. Compositional based fingerprints can potentially reveal both the oil source and its possible adulteration. Here, electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) resolves and identifies literally thousands of distinct chemical components of commercial canola, olive, and soybean oils, without extraction or other wet chemical separation pretreatment. In negative-ion ESI FT-ICR MS, the acidic components of soybean oil are easily distinguished from those of canola and olive oil based on relative abundances of C(18) fatty acids, whereas olive oil differs from canola and soybean oil based on relative abundances of tocopherols. In positive-ion ESI FT-ICR MS, the three oils are readily distinguished according to the relative abundances of di- and triacylglycerols with various numbers of double bonds in the fatty acid chains. We demonstrate the detection of soybean oil as an adulterant of olive oil, based on relative abundances of members of each of several chemical families. We suggest that the detailed chemical compositions of vegetable oils can be used to characterize them and to detect and identify adulterants.

Characterization of iron‐gall inks in historical manuscripts and music compositions using x‐ray fluorescence spectrometry

AbstractThe qualitative and quantitative investigation of historical iron‐gall inks using micro‐XRF spectrometry is a suitable method for analyzing composition fingerprints of different ink types. The quantitative analysis is based on a model that takes into account the inhomogeneity and the layer structure of archaeometric samples. Starting from these composition fingerprints, it is possible to characterize distinguishable inks of one artist to classify different chronological ink types and, further, to date unknown fragments that have not so far been integrated into the lifework of an artist. The first qualitative and quantitative investigations of the manuscript ‘Faust I and II’ and of the music composition ‘The Magic Flute’ demonstrate impressively the identification of J. W. v. Goethe's and W. A. Mozart's artistic work with modern scientific methods. Further investigations on A. v. Arnim's manuscript ‘Studien zu Naturwissenschaften’ provide evidence that the diversity of various degradation mechanisms of iron‐gall inks could be mainly caused by different inorganic compositions. Copyright © 2004 John Wiley & Sons, Ltd.

Fingerprinting suspended sediment sources in a large urban river system

Very few studies have attempted to quantify the sources of suspended sediment transported in urban river systems. In this study, statistically verified composite fingerprints and a multivariate mixing model have been used to identify the main sources of the suspended sediment transported by the River Aire and its main tributary, the River Calder. Because of the polluted nature of the Aire/Calder catchment and its effect on fingerprint property concentrations, source tracing was undertaken separately for the upper and lower reaches. The mean contributions from individual source types (i.e. surface materials from woodland, uncultivated and cultivated areas, channel bank material, road dust and solids from sewage treatment works) varied between the upper and lower reaches of the rivers, reflecting the change in land use from primarily pasture and moorland in the upper reaches to mainly urban areas (with some cultivated land) in the lower reaches. The suspended sediment in the upper reaches of the River Aire originates largely from channel bank sources (43–84%) and from uncultivated topsoil (16–57%). In the lower reaches of the Aire/Calder system, local sources of cultivated topsoil contribute 20–45% of the suspended sediment load and there is a significant contribution from urban sources, such as road dust (19–22%) and solids from sewage treatment works (14–18%). In the upper reaches, the proportion of sediment derived from each of the two main geological areas corresponds broadly to the proportion of the catchment occupied by each geological area. The relative contribution from the Rivers Aire and Calder to the suspended sediment load transported below the confluence demonstrates that most of the sediment is derived from the River Calder.

조합형 고정점 알고리즘에 의한 신경망 기반 독립성분분석

본 연구에서는 신경망 기반 독립성분분석의 분리성능을 개선하기 위해 할선법과 모멘트의 조합형 고정점 알고리즘을 제안하였다. 할선법은 독립성분 상호간의 정보를 최소화하는 목적함수의 근을 근사적으로 구함으로써 계산과정을 단순화하여 좀 더 개선된 분리성능을 얻기 위함이고, 모멘트는 계산과정에서 발생하는 발진을 억제하여 보다 빠른 분리속도를 얻기 위함이다. 이렇게 하면 할선법이 가지는 근사성에 따른 우수성과 과거의 속성을 반영하여 발진을 억제하는 모멘트의 우수성을 동시에 살릴 수 있다. 제안된 알고리즘을 <TEX>$256\times{256}$</TEX> 픽셀의 8개 지문과 <TEX>$512\times{512}$</TEX> 픽셀의 10개 영상으로부터 임의의 혼합행렬에 따라 생성된 복합지문과 복합영상을 각각 대상으로 시뮬레이션 한 결과, 뉴우턴법에 기초한 기존의 알고리즘과 할선법만에 기초한 알고리즘보다 각각 우수한 분리률과 빠른 분리속도가 있음을 확인하였다. 또한 할선법의 이용은 뉴우턴법을 이용한 고정점 알고리즘보다 초기값에도 덜 의존하며, 문제의 규모가 커짐에 따른 비현실적인 분리시간도 해결할 수 있음을 확인하였다. This paper proposes an efficient hybrid fixed-point (FP) algorithm for improving performances of the independent component analysis (ICA) based on neural networks. The proposed algorithm is the FP algorithm based on secant method and momentum for ICA. Secant method is applied to improve the separation performance by simplifying the computation process for estimating the root of objective function, which is to minimize the mutual informations of the independent components. The momentum is applied for high-speed convergence by restraining the oscillation if the process of converging to the optimal solution. It can simultaneously achieve a superior properties of the secant method and the momentum. The proposed algorithm has been applied to the composite fingerprints and the images generated by random mixing matrix in the 8 fingerprints of <TEX>$256\times{256}$</TEX>-pixel and the 10 images of <TEX>$512\times{512}$</TEX>-pixel, respectively. The simulation results show that the proposed algorithm has better performances of the separation speed and rate than those using the FP algorithm based on Newton and secant method. Especially, the secant FP algorithm can be solved the separating performances depending on initial points settings and the nonrealistic learning time for separating the large size images by using the Newton FP algorithm.

Selecting fingerprint properties for discriminating potential suspended sediment sources in river basins

The absence of guidelines for pre-selecting the most effective combination of properties for inclusion in a composite fingerprint represents a key methodological uncertainty hampering the wider adoption of the fingerprinting approach for identifying suspended sediment sources. This contribution reports a preliminary attempt to address this issue by testing the discrimination of potential sediment sources within a number of contrasting river basins in the UK and Africa, afforded by a range of sediment properties. Statistical analysis confirms that there is no single diagnostic property capable of discriminating the range of potential suspended sediment sources in the study basins. The use of composite fingerprints based on several constituents drawn from a single group of properties consistently improves sediment source discrimination. However, the level of discrimination afforded by a particular combination of properties is not consistent between the study catchments. Composite fingerprints incorporating constituents selected from several groups of properties using a stepwise statistical selection procedure consistently provide the most robust discrimination of potential sediment sources. Whilst it is not possible to identify a universally applicable optimum composite fingerprint, the results suggest that at present, the most effective means of optimising sediment source discrimination is to identify a number of groups of properties for subsequent use in the establishment of a composite fingerprint. More specifically, this study suggests that measurements of a combination of acid and pyrophosphate–dithionite extractable metals, base cations and organic constituents should provide an effective basis for establishing composite fingerprints for discriminating individual sediment source types. Radiometric properties can also provide useful information for improving sediment source discrimination. The final choice of the groups of properties will necessarily reflect the laboratory facilities available.

Suspended sediment source fingerprinting in a small tropical catchment and some management implications

The targeting of sediment management strategies is a key requirement in developing countries because of the limited resources available. Such targeting is, however, hampered by the lack of reliable information on catchment sediment sources. This paper reports the results of using a quantitative composite fingerprinting technique to estimate the relative importance of the primary potential sources within the upper Kaleya catchment (63 km 2) in southern Zambia. During the study period (1997–9), the load-weighted mean relative contributions to the sediment load sampled at the catchment outlet were in the order: commercial cultivation (2.0%), bush grazing (17.1%), channel banks/gullies (17.2%) and communal cultivation (63.7%). Although influenced by the timing of sediment sample collection, these results are judged to provide a meaningful assessment of sediment sources in the Kaleya catchment. They indicate that improved environmental management strategies for the study area must be comprehensive and need to reduce surface erosion and hillslope/channel connectivity in areas of bush grazing and both communal and commercial cultivation and to control gully development.

Suspended sediment sources in two small lowland agricultural catchments in the UK

In recent years there has been increasing recognition of the need to include sediment control strategies within catchment management plans. Information on the source of the sediment transported by a river is an important requirement for designing effective sediment control strategies. This paper uses the source fingerprinting approach to establish suspended sediment sources within two small (<4 km 2) lowland agricultural catchments in the UK, which are both extensively under drained. Representative samples of suspended sediment were collected from both catchments to encompass the expected inter- and intra-storm variability in sediment source. Statistically verified composite fingerprints and multivariate mixing models, incorporating particle size correction factors, were used to estimate the relative contribution of the potential sediment sources. These included surface sources (classified by land use, geology and soil type), eroding channel banks and field drains (subsurface sources). Field drains were shown to be important suspended sediment sources in both catchments, accounting for 27–55% of the sediment yields. Bank erosion contributes ca. 10% or less of the sediment yields. Surface sources were found to be important in both catchments contributing between 34–65% of the sediment yield. The above estimates of the relative contribution of the individual sediment sources within the study catchments to the overall sediment yield were shown to conceal significant inter- and intra-storm variability in the source contributions.

Improved repetitive-element PCR fingerprinting of Salmonella enterica with the use of extremely elevated annealing temperatures.

Modified thermal cycling conditions were explored in an effort to improve the reproducibility and resolving power of repetitive-element PCR (rep-PCR) fingerprinting. Assay performance was rigorously evaluated under standard and modified cycling conditions, using as a test set 12 strains putatively representing 12 serovars of Salmonella enterica. For all three fingerprint types (ERIC2, BOXA1R, and composite fingerprints), the use of extremely elevated annealing temperatures plus an initial "touchdown" cycling routine yielded significant improvements in day-to-day reproducibility and discriminating power despite the somewhat sparser appearance of the fingerprints. Modified cycling conditions markedly reduced the variability of fingerprints between cyclers, allowing fingerprints from different cyclers to be analyzed together without the degradation of assay performance that occurred with between-cycler analyses under standard cycling conditions. With modified cycling, composite fingerprints exhibited the lowest reproducibility but the highest net discriminating power of the three fingerprint types. rep-PCR fingerprints led to the discovery of a serotyping error involving one of the 12 test strains. These data demonstrate that modified cycling regimens that incorporate elevated annealing temperatures (with or without an initial touchdown routine) may markedly improve the performance of rep-PCR fingerprinting as a bacterial typing tool.

A review and synthesis of monoterpene speciation from forests in the United States

The monoterpene composition (emission and tissue internal concentration) of major forest tree species in the United States is discussed. Of the 14 most commonly occurring compounds ( α-pinene, β-pinene, Δ 3-carene, d-limonene, camphene, myrcene, α-terpinene, β-phellandrene, sabinene, ρ-cymene, ocimene, α-thujene, terpinolene, and γ-terpinene), the first six are usually found to be most abundant. Expected regional variability based on the monoterpene composition fingerprints and corresponding tree species distribution and abundance is examined. In the southeast, α-pinene and β-pinene seem to dominate monoterpene emissions, while in the northern forests emissions are distributed more evenly among the six major compounds. In some parts of western forests, β-pinene and Δ 3-carene can be more abundant than α-pinene. Among the other eight compounds, β-phellandrene and sabinene occasionally are significant percentages of expected local monoterpene emissions. Ocimene and ρ-cymene are estimated to be more common in regions dominated by deciduous broadleaf forests, although total emission rates are generally lower for these forests relative to those dominated by conifers. These percentages are compared with monoterpene composition measured in ambient air at various sites. Estimated monoterpene emission composition based on local forest species composition agrees fairly well with ambient measurements for the six major compounds. The past assumption that α-pinene composes approximately 50% of total monoterpene emissions appears reasonable for many areas, except for possibly the northern coniferous forests and some areas in the west dominated by true firs, spruce, and western pines (lodgepole and ponderosa pines). The oxygenated monoterpenes such as camphor, bornyl acetate, and cineole often compose high percentages of the monoterpenes within plant tissues, but are much less abundant in emission samples. Even after adjusting for lower vapor pressures of these compounds, emission rates relative to the hydrocarbon monoterpenes are often lower than would be expected from their internal concentrations. More study is warranted on monoterpene emission rates and composition, especially from the spruces, true firs, hemlocks, cedars, and some deciduous species such as the maples. Non-invasive canopy level and whole ecosystem flux studies are also needed to establish uncertainty estimates for monoterpene emission models.

An active subcontinental mantle volatile system in the western Eger rift, Central Europe: gas flux, isotopic (He, C, and N) and compositional fingerprints

The composition and flux of gas emanations, and the isotopic ratios of CO 2, He and N 2 of 74 mineral springs and dry gas vents (mofettes) in the western Eger rift (Czech Republic) have been analyzed. Four geochemically similar, but tectonically separate, gas escape centers are distinguishable, out of which 3 show a free gas flux >85000 dm 3 h −1. All gases from the centers are CO 2-rich (>99 vol.%) and have δ 13C values ranging from −1.8 to −4.0‰. 3He/ 4He ratios are as high as R/R a = 5, and are among the highest measured in Europe. The discharge of the gas mixture decreases with distance from the emanation centers with both decreasing fractions of CO 2 and δ 13C values, whereas the fractions of N 2 and trace gases increase. These changes in chemical and isotopic composition are associated by a decrease in R/R a ratios from about 5 in the centers to <2 in the peripheries. The changes of the contents and isotopic composition of CO 2 can be explained by physico-chemical fractionations of CO 2 between gaseous and aqueous phases. Towards the periphery, the contents of free CO 2 and its δ 13C are reduced by dissolution of CO 2 in groundwater, whereby the content of N 2 increases. 3He/ 4He ratios give evidence for mixing of He from both a deep-seated magmatic and a crustal source. The gas emanation centers, with their strongly magmatic δ 13C value of about −2.7‰, seem to outline the intersections of the Eger rift and the Mariánské Lázně fault, which are considered to represent a deep-reaching fracture system that enables the ascent of gases from a magmatic body in the European subcontinental mantle (SCM). Therefore, the European SCM is suspected to be the main source of CO 2. The most mantle-like He (and probably N 2) occurs in the centers of gas release. The total regional gas flux in the western Eger rift is determined to be 3.6 × 10 8 mol a −1. When related to the investigated area of 1500 km 2, flux densities greater than 0.24 × 10 6, 52, and 0.65 mol km −2 a −1 for CO 2, N 2 and He respectively are calculated.