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The tree-ring stable C, O and H isotope compositions have proven valuable for examining past changes in the environment and predicting forest responses to environmental change. However, we have not yet recovered the full potential of this archive, partly due to a lack understanding of fractionation processes resulting from methodological constraints. With better understanding of the biochemical and tree physiological processes that lead to differences between the isotopic compositions of primary photosynthates and the isotopic compositions of substrates deposited in stem xylem, more reliable and accurate reconstructions could be obtained. Furthermore, by extending isotopic analysis of tree-ring cellulose to intra-molecular level, more information could be obtained on changing climate, tree metabolism or ecophysiology. This chapter presents newer methods in isotope research that have become available or show high future potential for fully utilising the wealth of information available in tree-rings. These include compound-specific analysis of sugars and cyclitols, high spatial resolution analysis of tree rings with UV-laser, and position-specific isotope analysis of cellulose. The aim is to provide the reader with understanding of the advantages and of the current challenges connected with the use of these methods for stable isotope tree-ring research.

Aim The aim was to decipher Europe‐wide spatio‐temporal patterns of forest growth dynamics and their associations with carbon isotope fractionation processes inferred from tree rings as modulated by climate warming. Location Europe and North Africa (30‒70° N, 10° W‒35° E). Time period 1901‒2003. Major taxa studied Temperate and Euro‐Siberian trees. Methods We characterize changes in the relationship between tree growth and carbon isotope fractionation over the 20th century using a European network consisting of 20 site chronologies. Using indexed tree‐ring widths (TRWi), we assess shifts in the temporal coherence of radial growth across sites (synchrony) for five forest ecosystems (Atlantic, boreal, cold continental, Mediterranean and temperate). We also examine whether TRWi shows variable coupling with leaf‐level gas exchange, inferred from indexed carbon isotope discrimination of tree‐ring cellulose (Δ13Ci). Results We find spatial autocorrelation for TRWi and Δ13Ci extending over a maximum of 1,000 km among forest stands. However, growth synchrony is not uniform across Europe, but increases along a latitudinal gradient concurrent with decreasing temperature and evapotranspiration. Latitudinal relationships between TRWi and Δ13Ci (changing from negative to positive southwards) point to drought impairing carbon uptake via stomatal regulation for water saving occurring at forests below 60° N in continental Europe. An increase in forest growth synchrony over the 20th century together with increasingly positive relationships between TRWi and Δ13Ci indicate intensifying impacts of drought on tree performance. These effects are noticeable in drought‐prone biomes (Mediterranean, temperate and cold continental). Main conclusions At the turn of this century, convergence in growth synchrony across European forest ecosystems is coupled with coordinated warming‐induced effects of drought on leaf physiology and tree growth spreading northwards. Such a tendency towards exacerbated moisture‐sensitive growth and physiology could override positive effects of enhanced leaf intercellular CO2 concentrations, possibly resulting in Europe‐wide declines of forest carbon gain in the coming decades. Spanish Government, Grant/Award Number: AGL2015‐68274 ‐C3 ‐3‐R; Sixth Framework Programme, Grant/AwardNumber: EVK2‐2001 ‐00237; Seventh Framework Programme, Grant/AwardNumber: COST ‐STSM ‐ECOST ‐STSM ‐FP1304‐140915‐066395 and ERANET‐Mundus program (Grant agreement 20112573)

A common recommendation in the field of animal chemosignaling is to store and transport scent samples frozen, since they are likely to change with time and degrade due to bacterial activity inside the sample containers and the loss of the most volatile compounds. However, we still ignore the exact pattern of change or degradation for these types of samples. Here we experimentally tested the stability of primate scent samples during analytical procedures. For this purpose, we used swabs of naturally deposited glandular secretions from captive tamarins (Neotropical primates) analyzed by headspace gas chromatography-mass spectrometry. We successively extracted the samples by solid-phase microextraction, while controlling for the delay between extractions, and compared the number of compounds detected in the samples under each condition. We found that compounds were lost and transformed over time inside the sample vials. Such natural decay of scent signals is likely to contribute to the long term information transmitted. We found no evidence that long delays at room temperature affected sample chemical composition more than short delays. Nonetheless, we showed that repeated extraction of a sample increased the loss of compounds. The changes in sample chemical composition observed over time in this experiment support standard recommendation to avoid storing samples for long periods at room temperature and to extract each sample only once, in order to ensure optimum results.

Chemosignals are mediators of social interactions in mammals, providing con- and hetero-specifics with information on fixed (e.g. species, sex, group and individual identity) and variable (e.g. social, reproductive and health status) features of the signaler. Yet methodological difficulties of recording and quantifying odor signals, especially in field conditions, have hampered studies of natural systems. We present the first use of the Torion® portable gas chromatography-mass spectrometry (GC-MS) instrument for in situ chemical analysis of primate scents. We collected and analyzed swab samples from the scent-glands and skin from 13 groups (57 individuals) of two sympatric species of wild emperor tamarins, Saguinus imperator, and Weddell’s saddleback tamarins, Leontocebus weddelli (Callitrichidae). In total, 11 compounds of interest (i.e. probably derived from the animals) could be detected in the samples, with 31 of 215 samples containing at least one compound of interest. The composition of these 31 samples varied systematically with species, group, sex and breeding status. Moreover, we tentatively identified seven of the compounds of interest as methyl hexanoate, benzaldehyde, ethyl hexanoate, acetophenone, a branched C15 alkane, 4-methoxybenzaldehyde and hexadecan-1-ol. As the field of primate semiochemistry continues to grow, we believe that portable GC-MS instruments have the potential to help make progress in the study of primate chemosignaling in field conditions, despite limitations that we encountered. We further provide recommendations for future use of the Torion® portable GC-MS for in situ analyses.

Olfactory communication is an important mediator of social interactions in mammals, thought to provide information about an individual’s identity and current social, reproductive, and health status. In comparison with other taxa such as carnivores and rodents, few studies have examined primate olfactory communication. Tamarins (Callitrichidae) conspicuously deposit odorous secretions, produced by specialized scent glands, in their environment. In this study, we combined behavioral and chemical data on captive cotton-top tamarins, Saguinus oedipus, and bearded emperor tamarins, S. imperator subgrisescens, to examine the role of olfactory communication in the advertisement of species, sex, and reproductive status. We observed no difference in scent-marking behavior between species; however, females marked more frequently than males, and reproductive individuals more than non-reproductive ones. In addition, tamarins predominantly used their anogenital gland when scent-marking, followed by the suprapubic gland. We collected swabs of naturally deposited tamarin anogenital scent marks, and analyzed these samples using headspace gas chromatography-mass spectrometry. Despite a limited sample size, we established differences in tamarin anogenital mark chemical composition between species, sex and reproductive status, and identified 41 compounds. The compounds identified, many of which have been reported in previous work on mammalian semiochemistry, form targets for future bioassay studies to identify semiochemicals. Our non-invasive method for collecting deposited scent marks makes it a promising method for the study of olfactory communication in scent-marking animal species, applicable to field settings and for the study of elusive animals.

Much effort is being expended in the reconstruction of surrogate climatic and environmental data over several time scales. The history of climate is of exceptional interest and importance and has been investigated through traditional methods such as floral and faunal analysis, pollen analysis, tree ring widths and tree ring X-ray analysis. The sole source of carbon in the growth rings of trees may be assumed to be derived from the carbon dioxide of the atmosphere and the ring constituents actively record the variations of atmospheric d13C. Much progress has been made in understanding the mechanisms of isotopic fractionation that can occur during the complex processes between water entering the tree and the incorporation of hydrogen and oxygen in the cellulose of tree rings.

Chemosignals are mediators of social interactions in mammals, providing con- and hetero-specifics with information on fixed (e.g., species, sex, group, and individual identity) and variable (e.g., social, reproductive, and health status) features of the signaler. Yet, methodological difficulties of recording and quantifying odor signals, especially in field conditions, have hampered studies of natural systems. We present the first use of the Torion® portable gas chromatography-mass spectrometry (GC-MS) instrument for in situ chemical analysis of primate scents. We collected and analyzed swab samples from the scent glands and skin from 13 groups (57 individuals) of two sympatric species of wild emperor tamarins, Saguinus imperator, and Weddell's saddleback tamarins, Leontocebus weddelli (Callitrichidae). In total, 11 compounds of interest (i.e., probably derived from the animals) could be detected in the samples, with 31 of 215 samples containing at least one compound of interest. The composition of these 31 samples varied systematically with species, group, sex, and breeding status. Moreover, we tentatively identified seven of the compounds of interest as methyl hexanoate, benzaldehyde, ethyl hexanoate, acetophenone, a branched C15 alkane, 4-methoxybenzaldehyde, and hexadecan-1-ol. As the field of primate semiochemistry continues to grow, we believe that portable GC-MS instruments have the potential to help make progress in the study of primate chemosignaling in field conditions, despite limitations that we encountered. We further provide recommendations for future use of the Torion® portable GC-MS for in situ analyses.

A lightweight, portable device for extracting stuck or broken increment borers is presented and its operation described. The “Decorum” extractor is compact and weighs less than 400 g. It is easily carried in a belt pouch or pocket and is both reliable and easy to operate. The extractor does not require fixed tie points nor does it damage the tree. It offers an effective solution to a widely occurring problem in dendrochronology and forest research.

Accurate modelling of long-term changes in plant stomatal functioning is vital to global climate change studies because changes in evapotranspiration influence temperature via physiological forcing of the climate. Various stomatal models are included in land surface schemes, but their robustness over longer timescales is difficult to validate. We compare the performance of three stomatal models, varying in their degree of complexity, and coupled to a land surface model. This is done by simulating the carbon isotope ratio of tree leaves (δ(13) Cleaf ) over a period of 53 years, and comparing the results with carbon isotope ratios obtained from tree rings (δ(13) Cstem ) measured at six sites in northern Europe. All three stomatal models fail to capture the observed inter-annual variability in the measured δ(13) Cstem time series. However, the Soil-Plant-Atmosphere (SPA) model performs significantly better than the Ball-Berry (BB) or COX models when tested for goodness of fit against measured δ(13) Cstem . The δ(13) Cleaf time series simulated using the SPA model are significantly positively correlated (p < 0.05) with measured results over the full time period tested, at all six sites. The SPA model underestimates inter-annual variability measured in δ(13) Cstem , but is no worse than the BB model and significantly better than the COX model. The inability of current models to adequately replicate changes in stomatal response to rising levels of CO2 concentrations, and thus to quantify the associated physiological forcing, warrants further investigation. © 2013 Blackwell Publishing Ltd. (Less)

Tree-ring stable carbon isotope ratios (δ13C) often display a decline over the industrial period (post-AD1850) that is only partly explained by changes in the isotopic ratio of carbon dioxide (CO2) and may represent a response to increased atmospheric concentrations of CO2 (ca). If this is not addressed, reconstructions using long tree-ring stable isotope chronologies calibrated using the modern period, for which meteorological records are available, may be compromised. We propose a correction procedure that attempts to calculate the δ13C values that would have been obtained under pre-industrial conditions. The correction procedure uses nonlinear (loess) regression but the magnitude of the adjustment made is restricted by two logical constraints based on the physiological response of trees: first, that a unit increase in ca cannot result in more than the same unit increase in the internal concentration of CO2 (ci), and second, that increases in water-use efficiency as a result of an increase in ca are limited to maintaining a constant ci/ca ratio. The first constraint allows retention of a falling trend in δ13C, which exceeds that which could logically be attributed to a passive response to rising ca. The second constraint ensures that any increase in δ13C, reflecting a change in water-use efficiency beyond maintenance of a constant ci/ca, is not removed. The procedure is tested using ‘pseudoproxies’, to demonstrate the effect of the correction on time-series with different shapes, and data from three sites in Finland and Norway. Two of the time-series retain a significant trend after correction, and in all three cases the correction improves the correlation with local meteorological measurements.

The dorsal gland secretions of captive-reared male and female Chacoan peccaries (Catagonus wagneri) were analyzed by gas chromatography-mass spectrometry. C8-C19 carboxylic acids, squalene, cholesterol, cholestanol, and cholest-7-en-3-ol were present in both males and females. Heptylbenzene, C14-C18 methyl esters, and an isomer of springene were observed in males. C15-C19 aldehydes were observed in females. The composition of the dorsal gland secretions of C. wagneri is compared to what has been reported for other peccaries (Tayassu spp.).

The incorporation of stable isotopes improves the assessment of glucose metabolism and, with some researchers using two tracers, 2H-glucose assessed by gas chromatography/mass spectrometry (GC/MS) and 13C-glucose by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS), a common derivative for both is advantageous. The most commonly used derivatives for GC/MS are inappropriate for GC/C/IRMS as additional functional groups dilute the label. We therefore considered the suitability of six derivatives for both GC/MS and GC/C/IRMS. Glucose alkylboronates were prepared by adding the appropriate alkylboronic acid (butyl- or methylboronic acid) in pyridine to desiccated glucose. The derivatisation was completed by reacting this with either (a) acetic anhydride or trifluoroacetic anhydride (acetate derivatives) or (b) bis(trimethylsilyl)trifluoroacetamide BSTFA (TMS derivatives). All six derivatives were assessed using GC/MS and 13C GC/C/IRMS. Neither TMS derivative exhibited any signal intensity in the molecular ion, although a M-15 ion showed good agreement between experimental and theoretical data and, whilst still low in intensity, could be suitable for isotope work. Similarly, none of the acetate derivatives showed any intensity at the molecular ion although three key fragmentation series were identified. The most attractive sequence, initiated by the loss of 1,2 cyclic boronate, resulted in the main fragment ion of interest, m/z 240, corresponding to the fluorinated methylboronate derivate. Minimal carbon and hydrogen atoms are added to this derivative making it an excellent choice for stable isotope work, while proving suitable for analysis by both GC/MS and GC/C/IRMS. Copyright © 2007 John Wiley & Sons, Ltd.

The major histocompatibility complex (MHC) is the most polymorphic genetic system known in vertebrates. Decades of research demonstrate that it plays a critical role in immune response and disease resistance. It has also been suggested that MHC genes influence social behavior and reproductive phenomena. Studies in laboratory mice and rats report that kin recognition and mate choice are influenced by olfactory cues determined at least in part by an individual's MHC genes. This issue has stimulated intense but controversial research. However, work in this field has only been carried out in rodents and humans. Thus far, no study has directly investigated the relationship between olfactory cues and MHC genotype in nonhuman primates. Furthermore, other genetic loci, including those linked to the MHC, have not been ruled out as the primary influence on odor profiles. To explore the relationship between individual odor profiles and MHC alleles, we are studying ring-tailed lemurs (Lemur catta). These animals are an ideal model species because they are extremely scent-oriented and their behaviors suggest that olfactory signals form an important part of their intra- and intergroup communication systems. Individual odor profiles from tail and scent gland samples were generated for six males using gas chromatography mass spectrometry (GC-MS). MHC genotypes were identified using polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE). The GC-MS analyses demonstrated a difference between profiles obtained from tail and scent gland samples. Although our sample size is relatively small and statistical significance could not be obtained, our analyses suggest a relationship between MHC and concentrations of volatile compounds. While these results are preliminary, they support the need for further studies of the MHC and olfactory signals in lemurs and other primates.

α-Cellulose was isolated from four samples of Scots pine (Pinus sylvestris L.). Each sample was divided into two portions. One portion had the resins removed by solvent extraction prior to removal of lignins by treatment with acidic sodium chlorite solution and treatment with sodium hydroxide solution to remove hemicelluloses. The other portion was processed in the same way apart from the solvent extraction step. The isolated wood constituents were characterised by attenuated total reflectance Fourier transform infrared (ATR/FT-IR) spectroscopy. The infrared spectra of the resulting α-cellulose samples were identical indicating that treatment with acidic sodium chlorite and sodium hydroxide was sufficient to remove resins. The values of the stable isotope ratios (carbon, oxygen and hydrogen) for each pair of α-cellulose sub-samples also showed no significant differences within the reproducibility of the methods. The implication of these studies demonstrate that the customary step of resin extraction from pine is unnecessary if sodium chlorite and sodium hydroxide are used for the isolation of α-cellulose following the technique described in this paper. In addition, the study demonstrates that the oxygen isotope ratio of the water used for cellulose extraction does not influence the stable isotope values in the α-cellulose obtained. The importance of isotopic homogeneity within the cellulose sample is also highlighted.

The biological activity of essential oil volatiles from Tagetes minuta L. (Mexican marigold) against three aphid species was investigated in a series of laboratory experiments. The aphid species (Homoptera: Aphididae) studied were: Acyrthosiphon pisum (Harris) (pea aphid), Myzus persicae (Sulzer) (peach-potato aphid), and Aulacorthum solani (Kaltenbach) (glasshouse and potato aphid). Tagetes minuta oil volatiles significantly reduced aphid reproduction (up to 100% after 5 days of exposure). The effect depended on the quantity of essential oil used, and varied with the aphid species tested. Pea aphids were the most susceptible. Tagetes minuta oil was fractionated by vacuum distillation. Fractions and three pure compounds (limonene, (Z)-ocimene, and β-caryophyllene) were tested using the same experimental technique. The chemical composition of the volatiles was investigated by headspace-solid phase microextraction-gas chromatography mass spectrometry (HS-SPME-GCMS), and the main constituents of the oil were identified. Overall, applied in equal quantity, fractions predominantly containing sesquiterpenes and oxygenated monoterpenoids were more effective in restricting aphid population growth than fractions predominantly containing monoterpenes. When tested as a pure compound, the sesquiterpene β-caryophyllene produced a greater effect than the monoterpenes limonene and ocimene. The study demonstrates that T. minuta oil volatiles have potential for aphid control.

In many species, chemical signals are important in the context of intraspecific communication. European badgers (Meles meles) use the secretion of their subcaudal gland to mark both the environment and conspecifics. In this paper, we investigated the chemical composition of subcaudal gland secretions and how it varies among individuals according to group membership, season, sex, age, body condition, and reproductive status. We analyzed 66 samples by gas chromatography using a mass-spectrometer as detector. We found 110 different components, of which 21 were present in every profile. The chemical composition of the secretions proved to be highly individual-specific, but no single peak was found to be typical for one of the investigated categories (season, sex, etc.). Analyses of the relative area (% area) that every peak contributed to the overall profile area showed that, in general, group members have more similar profiles than do badgers from different groups. Composition varied over seasons and between sexes and was influenced by age, body condition, and reproductive status. We, therefore, conclude that the secretion not only encodes group membership and individuality as previously assumed, but might also convey information about fitness-related parameters.

Individuality in body odors has been described in a variety of species, but studies on time-related variation in individual scent are scarce. Here, we use GC-MS to investigate how chemical composition of subcaudal gland secretions of European badgers (Meles meles) varies over days, seasons, and from year to year, and how secretions change with the length of time for which they are exposed to the environment. Samples were divided into subsamples—one was frozen immediately and the remaining ones frozen after 2, 6, 12, 24, and 48 hr, respectively—and many individual-specific characteristics of the scent-profiles remained stable over time. However, two components were negatively correlated with time, thus providing the possibility to determine the age of scent marks. The low variation found in scent profiles of samples collected from the same individual three days apart showed that the individual-specific scent is a true characteristic of the respective badger, and that trapping and subsequent sampling have little effect on the composition of subcaudal gland secretions. Long-term variation (i.e., over one year) in individual subcaudal scent profiles is not continuous, but periods of relative stability are followed by periods of rapid change, that can be related to badger biology. Annual variation between samples collected from the same individuals in winter 1998 and winter 1999, and in spring 1998 and spring 1999 was lower than seasonal variation. Therefore, the results of this study indicate the potential of an individual-specific scent signature in the subcaudal gland secretions of badgers evidencing that individual recognition is of high importance in this species.

Annual latewood δ18O values from oak (Quercus robur L.) are presented for the period 1895–1994 for four trees growing in eastern England. We demonstrate, using the δ18O values of precipitation from Wallingford (1982–1994) and the longer time-series from Groningen (1965–1994), that the δ18O values of winter precipitation had the strongest influence on the δ18O values of tree-ring cellulose. The influence of winter precipitation on the spring/summer formed latewood may be explained by several factors: most soil water is replenished during the winter, water may take several months to penetrate the unsaturated zone, and oaks may sample water from lower in the profile during times of water stress. The δ18O values of oak latewood cellulose were also significantly (P

Secretions from the dorsal gland of male and female free-ranging adult white-lipped peccaries (Tayassu pecari) from Bolivia were analyzed by gas chromatography–mass spectrometry. Fifty compounds were identified, some provisionally. Secretions of both sexes contain saturated and unsaturated C5–C18 carboxylic acids as well as isomers of the diterpene springene. The females' secretions uniquely possess farnesyl esters of C8 and C10 carboxylic acids, whereas the males' secretions uniquely showed two compounds provisionally identified as monounsaturated C16 lactones. Saturated high-molecular-weight esters of C10 carboxylic acids are more abundant in the females' secretions than in those of the males. The secretions of both sexes also contain monoalkanoate esters of methylhydroquinone as major components.

Annual values of carbon isotope ratios for the period 1898–1990 are reported for Scots pine (Pinus sylvestris) growing in the valley of the lower river Ob in western Siberia. The data show highly significant inverse correlation to river flow over the period of instrumental records (1934–1990), although the strength of the relationship shows some dependence on the distance of the tree from the edge of the river. The predictive power of a linear regression model derived from the second half of the data set is validated by comparing the river flow for the first half of the period with values predicted by the model. Agreement is highly significant (r=0.80, P

Annual oak (Quercus robur L.) latewood δ 13 C values are presented for the period 1895-1994 from two sites with different hydrological characteristics. Both ring width and δ 13 C indices record high-frequency common forcing better than lower-frequency forcing. At both sites the high-frequency variance in the δ 13 C indices of latewood cellulose is highly correlated with combined July and August environmental variables. The association between the high-frequency variance in annual ring width indices and climate is not as strong. Higher correlations with environmental variables were found for the high-frequency δ 13 C indices at the dry site (Sandringham) than at the wet site (Babingley), but the differences are not statistically significant. These results illustrate the need for routine signal quantification in isotope records and hence a requirement for between-tree replication of isotope series in future studies. High-frequency (year-to-year) interseries correlation is shown to be relatively strong, indicating that only small numbers of replicate series are needed to represent interannual isotope variability accurately. However, common signal variance is diminished at lower (decadal and longer period) frequencies. This implies a need for increased sample replication in order to achieve chronology confidence equivalent to that routinely produced for simple ring width data. This work demonstrates that significant high-frequency climate signals are contained in isotopic measurements of trees whose ring widths contain little or no such information.

Annual oak (Quercus robur L.) latewood δ13C values are presented for the period 1895–1994 for two sites with different hydrological characteristics in southwest Finland. No appreciable anthropogenic 13C depletion was observed in the time-series. δ13C indices record high-frequency common forcing better than lower-frequency forcing. High-frequency fluctuations in the δ13C indices are highly correlated with climatic variables. Cross correlation analysis of tree ring δ13C indices and climate variables show that there is no significant difference (p < 0.01) in the climate response of tree ring δ13C indices between the two sites. This work demonstrates that significant climate signals are contained in isotopic measurements of trees whose ring-widths contain little or no such information.

The climate sensitivity of carbon (δ(13)C), oxygen (δ(18)O) and hydrogen (δ(2)H) isotope signatures in tree-ring cellulose of Abies alba Mill. from a marginally industrialized area of Franconia (Germany) was analysed for the last 130 years. All isotopes preserve climatic signals up to c. 1950 AD. After 1950 we observe a clear reduction in climate sensitivity of δ(13)C and δ(2)H while δ(18)O - climate relations remain well pronounced. Nevertheless statistical tests implied that SO2 background emissions of West Germany had influenced isotope signatures long before 1950. The relationships between isotope values and concentrations of SO2, dust, O3 and NO2 at the regional level during the period 1979-2006 indicate that δ(13)C and δ(18)O were influenced primarily by SO2. The impact of SO2 on δ(2)H was negligible, but the observed reduction of climate sensitivity may be caused by synergic influences. The results have significant implications if isotope signatures from tree-rings from anthropogenic influenced regions are used to reconstruct past climate.

We describe the first reported method for the measurement of oxygen isotope ratios at each position in the glucose units of the cellulose molecule. The overall process comprises a series of synthetic organic sequences, by which α-cellulose is hydrolysed to glucose, and oxygen atoms at specific positions in the glucose molecule are removed in samples of benzoic acid for measurement of δ18O. Values of δ18O at specific positions in cellulose are calculated from these δ18O values and the overall δ18O value of the cellulose. We apply the method to determine the degree to which oxygen atoms at each position undergo isotopic exchange with water during heterotrophic cellulose synthesis, such as occurs in the cambium of trees. To do this we extract α-cellulose from wheat seedlings germinated in the dark in aqueous media of differing oxygen isotope ratios. Results indicate that oxygen atoms at positions 5 and 6 (O-5 and O-6 respectively) undergo around 80% exchange with medium water, O-3 undergoes around 50% exchange, and O-2 and O-4 do not undergo isotopic exchange. The results have important implications for extracting palaeoclimatic records from oxygen isotope time series obtained from tree ring cellulose. As O-5 and O-6 undergo significant exchange with medium water during heterotrophic cellulose synthesis, oxygen isotopes at these positions in tree ring cellulose should carry a predominantly trunk (source) water signal. On the other hand, O-2 and O-4 should retain the isotopic signature of leaf water in tree ring cellulose. Our method therefore potentially enables the separate reconstruction of past temperature and humidity data from oxygen isotope ratios of tree ring cellulose – something that has hitherto not been possible. The measured degrees of isotopic exchange are to some extent unexpected and cannot be fully explained using current biochemical mechanisms, suggesting that knowledge of these processes is incomplete.

The chemical composition of the volatile components of the anal gland secretion of mature and immature moles of both sexes was examined by gas chromatography and mass spectrometry. The compounds in the secretion of adult males appear to vary little throughout the year and are similar to those from the adult female outside the breeding season. The secretions are dominated by C5-C10 carboxylic acids. Female glands regress as they enter proestrus, accompanied by profound changes in the chemical composition of the secretion with early disappearance of the carboxylic acids. In juvenile moles, the composition of the secretion changes as the animal matures, with carboxylic acids becoming dominant only as the animal reaches maturity. Anal gland secretion probably plays an important role in territorial maintenance.

This study reports the influence of a 20th century pollution signal recorded in the δ13C and δ18O of absolutely dated tree rings from Quercus robur and Pinus sylvestris from southern England. We identify a correspondence between the inter-relationship and climate sensitivity of stable isotope series that appears to be linked to recent trends in local SO2 emissions. This effect is most clearly exhibited in the broadleaved trees studied but is also observed in the δ13C values of the (less polluted) pine site at Windsor. The SO2 induced stomatal closure leads to a maximum increase of 2.5‰ in the isotope values (δ13C). The combined physiological response to high pollution levels is less in δ18O than δ13C. The SO2 signal also seems to be present as a period of reduced growth in the two ring-width chronologies. Direct, quantitative correction for the SO2 effect represents a significant challenge owing to the nature of the records and likely local plant response to environmental pollution. Whilst it appears that this signal is both limited to the late industrial period and demonstrates a recovery in line with improvements in air quality, the role of atmospheric pollution during the calibration period should not be underestimated and adequate consideration needs to be taken when calibrating biological environmental proxies in order to avoid development of biased reconstructions.

In order to predict accurately how elevated atmospheric CO 2 concentrations will affect the global carbon cycle, it is necessary to know how trees respond to increasing CO 2 concentrations. In this paper, we examine the response over the period AD 1895–1994 of three tree species growing across northern Europe to increases in atmospheric CO 2 concentrations using parameters derived from stable carbon isotope ratios of trunk cellulose. Using the isotope data we calculate values of intrinsic water-use efficiency (IWUE) and intercellular CO 2 concentrations in the leaf ( c i ). Our results show that trees have responded to higher levels of atmospheric CO 2 by increasing IWUE whilst generally maintaining constant c i values. However, the IWUE of most of the trees in this study has not continued to rise in line with increasing atmospheric CO 2 . This behaviour has implications for estimations of future terrestrial carbon storage.

Two studies at three sites in the UK provided confirmation that systematic positive bias in NO2 diffusion tube measurement occurred because of changes to "within-tube" chemistry, rather than eddy diffusion at the mouth of the tube. In the first study in Cambridge, UK, sampler overestimation for 1 and 2 week exposures was compared to corresponding time-averaged monitor measurements (NO-NO2-NOx, O3) and weather variables. Noninearity between sampler and monitor NO2 measurements was interpreted in terms of spatial and temporal variations in relative and absolute availability of NO, NO2 and O3 at the site. A maximum overestimation occurred for an exposure mean NO2/NOx approximately 0.5. The separate contributions of reduced NO2 photolysis and eddy diffusion were compared in Study II using samplers of two materials, acrylic and quartz, and of different lengths (40, 55, 71 and 120 mm) at three sites: Norwich background, Cambridge intermediate, London kerbside. For compared sites, NO2 measured by acrylic samplers was significantly higher than for equivalent quartz samplers. For quartz samplers [NO2]mean was only just above the monitor at Norwich and London; sampler/monitor NO2 = 1.04 (P = 0.59) and 1.01(P = 0.76), respectively. For acrylic samplers the order of [NO2]mean was 40 mm > 120 mm > 71 mm > or = 55 mm. Excepting 40 mm samplers, this accords with a chemical bias where co-diffusing NO and 03 molecules in longer tubes have more time to react to form excess NO2. Bias in 40 mm samplers is discussed. Eddy diffusion is negligible for standard samplers because [NO2]mean was equivalent for 55 mm and 71 mm acrylic samplers and close to monitor NO2 for 71 mm quartz tubes. Both studies showed that sampler accuracy was dependent on location. Significantly, overestimation was greatest (approximately 3-4 ppb) where the NO2 annual mean was approximately 20 ppb, close to the UK and EU air quality standard of 21 ppb.

Factors concerning NO2 uptake by the absorbent triethanolamine (TEA) in NO2 diffusion tubes are examined. Although the nominal freezing point of TEA is 17.9-21.2 degrees C, we show that, for a range of aqueous TEA solutions (0-20%, H2O), no freezing occurs even at -10 degrees C. Therefore NO2 collection efficiency is unlikely to be impaired by low temperature exposure. The recovery of TEA from the meshes of exposed samplers is determined as approximately 98%, even after 42 days, showing that the stability in situ of TEA is unaffected by long-term exposure. A model of a diffusion tube sampling array for simultaneous exposures, with a 0.1 m sampler spacing, shows that NO2 uptake by individual samplers is not affected by the presence of neighbouring tubes in the array. This is confirmed by sampler precision at two Cambridge sites. Four sampler preparation methods are compared for differences in NO2 uptake of exposed samplers. All methods employ TEA as absorbent, transferred by either dipping meshes in a TEA-acetone solution or pipetting aliquots of a TEA-H2O solution onto the meshes. For samplers prepared by three of the methods, no difference in NO2 uptake is found, but for samplers prepared using a 50% v/v TEA-H2O solution, a mean reduction of 18% is found. Student's t-tests show that the difference is highly significant (Por = 0.001). Reasons for the difference are discussed.

Several dimethyl-1,2-dithiolanes are identified in the anal sac secretion of the weasel. We compare and contrast the results with previously published work.

We present details of a modified technique for the extraction of α-cellulose from wood samples. The revised technique, based upon the sodium chlorite oxidation method of Green (1963) utilises an ultrasonic bath and small Soxhlet thimbles to prepare α-cellulose from silvers of wholewood. These modifications facilitate the rapid batch processing of small wholewood samples to α-cellulose and yield a material with sufficient homogeneity as required for palaeoclimatic reconstruction.

Analysis of the marking fluid of two tigers (one Bengal and one Sumatran) by GC using an amine-specific column and a nitrogen-specific detector has shown the presence of the following amines: ammonia, methylamine, dimethylamine, trimethylamine, triethylamine, propylamine, and butane-1,4-diamine (putrescine). In contrast to previously published reports, we were unable to detect 2-phenylethylamine. The anal sac secretion was found to have a similar amine content.

Gas chromatographic analysis of the benzene obtained for radiocarbon dating revealed only very low levels (

The general solution is given for steady two-dimensional magnetohydrodynamic flows of an incompressible, inviscid, fluid having infinite electrical conductivity when the angle between the magnetic field and the velocity field is every where constant.

To understand recent climatic trends and possible future climatic change, it is necessary to examine the nature of past climatic variability. Proxy measures of past climatic fluctuations can be used to extend this record beyond the limited period of instrumental measurements. Regression-based techniques are generally used to define transfer functions, which describe the statistical relationship between these proxy estimates of past climate and measured climatic parameters. Although these regression-based techniques have been extremely successful, they can engender bias in the estimates if not used with care. More significantly, we show that if regression errors are explicitly calculated they are often similar in magnitude to the total range of the parameter being estimated, implying that such reconstructions of past climate cannot be regarded as truly precise. A novel approach based upon Bayes' theorem is introduced which appears to increase the statisti cal veracity of such climatic reconstructions.

Secretions of the dorsal gland of free-ranging adult male and female collared peccaries (Tayassu tajacu) were analyzed by gas chromatography-mass spectrometry. Both sexes contain (2E,6E,10E)-geranylgeraniol; squalene (allE isomer); and the following isomers of springene, a diterpene homolog of β-farnesene: (3E,6E,10E)-α-springene, (3Z,6E,10E)-α-springene, and (6E,10E)-β-springene. A diterpene alcohol and an additional isomer each of squalene and springene also were observed. Straight- and branched-chain esters abound in the secretions of females, but they were not detected in males.

Rate constants have been determined for reactions of various polyfluoropyridines with ammonia in water–dioxan (60 : 40 v/v) at 25 °C. Comparison of these rate constants allows the separate effects of fluorine atoms ortho, meta, and para to the reaction centre to be established. The activating influence decreases in the series ortho > metapara(31 : 23 : 0.26 relative to a hydrogen atom at the same position). The hitherto puzzling orientation of nucleophilic substitution in polyfluoro-pyridines and -benzenes is, therefore, accounted for by the activating influence of fluoro-substituents being at a maximum. A synthesis of 2,3,4,5-tetrafluoropyridine is described.

These experiments illustrate the common advantages of polymer-supported reagents and contrast the behavior of macroreticular resins and gel resins.

Rate constants and product analyses are provided for reactions of various chloropolyfluoropyridines with ammonia in dioxan–water (60: 40 v/v) at 25 °C. Comparison of these rate constants with the values for appropriate polyfluoropyridines allows the separate effects of chlorine atoms ortho, meta, and para to the reaction centre to be established. The activating influence of chlorine decreases in the series ortho > meta > para(86 : 24 : 6.9 relative to hydrogen atom at the same position). The rate constant ratios kcl : kF for chlorine orfluorine at the same position are: ortho ca. 3 : 1, meta ca. 1 : 1, and para ca. 2.6 : 1. These ratios have been measured for a number of different substitutions and are remarkably constant. The results help to explain the orientation and reactivity of nucleophilic substitution in polyhalogenoaromatic compounds.

Rate measurements for reactions of ammonia with polyfluopyridines and methoxide with polyfluorobenzenes indicate that the activating influence of fluorine, with respect to the point of nucleophilic attack, is in the order: meta > ortho > para. This leads to a more complete explanation of the orientation of nucleophilic substitution in polyfluoro-benzenes and -pyridines than the generally accepted one.