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1.
Diet–tissue isotopic relationships established under controlled conditions are informative for determining the dietary sources and geographic provenance of organisms. We analysed δ13C, δ15N, and non-exchangeable δ2H values of captive African grey parrot Psittacus erithacus feathers grown on a fixed mixed-diet and borehole water. Diet–feather Δ13C and Δ15N discrimination values were +3.8?±?0.3?‰ and +6.3?±?0.7?‰ respectively; significantly greater than expected. Non-exchangeable δ2H feather values (?62.4?±?6.4?‰) were more negative than water (?26.1?±?2.5?‰) offered during feather growth. There was no positive relationship between the δ13C and δ15N values of the samples along each feather with the associated samples of food offered, or the feather non-exchangeable hydrogen isotope values with δ2H values of water, emphasising the complex processes involved in carbohydrate, protein, and income water routing to feather growth. Understanding the isotopic relationship between diet and feathers may provide greater clarity in the use of stable isotopes in feathers as a tool in determining origins of captive and wild-caught African grey parrots, a species that is widespread in aviculture and faces significant threats to wild populations. We suggest that these isotopic results, determined even in controlled laboratory conditions, be used with caution.  相似文献   

2.
A survey study was conducted on man-made plantations located at two different areas in the arid region of Syria to determine the variations in natural abundances of the 15N and 13C isotopes in leaves of several woody legume and non-legume species, and to better understand the consequence of such variations on nitrogen fixation and carbon assimilation. In the first study area (non-saline soil), the δ15N values in four legume species (Acacia cyanophylla,?1.73 ‰ Acacia farnesiana,?0.55 ‰ Prosopis juliflora,?1.64 ‰; and Medicago arborea,+1.6 \textperthousand) and one actinorhizal plant (Elaeagnus angustifolia,?0.46 to?2.1 ‰) were found to be close to that of the atmospheric value pointing to a major contribution of N2 fixing in these species; whereas, δ15N values of the non-fixing plant species were highly positive. δ13C ‰; in leaves of the C3 plants were found to be affected by plant species, ranging from a minimum of?28.67 ‰; to a maximum of?23 ‰. However, they were relatively similar within each plant species although they were grown at different sites. In the second study area (salt affected soil), a higher carbon discrimination value (Δ13C ‰) was exhibited by P. juliflora, indicating that the latter is a salt tolerant species; however, its δ15N was highly positive (+7.03 ‰) suggesting a negligible contribution of the fixed N2. Hence, it was concluded that the enhancement of N2 fixation might be achieved by selection of salt-tolerant Rhizobium strains.  相似文献   

3.
A combination of C/N ratios, δ13C and δ15N values in suspended matter was used to examine the seasonal (late summer 2004 and spring 2005) relationship with hydrological characteristics of the River Sava watershed in Slovenia. The values of C/N ratios range from 1.2 to 19.1, δ13C values range from?29.2 to?23.0 ‰ and δ15N values from 0.5 to 16.7 ‰ and indicate that the samples are a mixture of two end members: modern soils and plant litter. A simple mixing model was used to indicate that soil organic carbon prevails over plant litter and contributes more than 50% of suspended material. The calculated annual particulate organic carbon flux is estimated as 5.2×1010 g C/year, the annual particulate nitrogen flux 8.5×109 g N/year and the total suspended solid flux is estimated to be 1.3×1012 g/year. Anthropogenic impact was detected only in a tributary stream of the River Sava, which is located in an agriculture–industrial area and is reflected in higher δ15N values in suspended matter and high nitrate concentrations in the late summer season.  相似文献   

4.
Stable hydrogen and oxygen isotopes were analysed in water samples from the River Danube and its tributaries during a longitudinal survey performed in August 2005 on Serbian territory. Danube river water data ranged from?80‰ to?66‰ for δ2H, and from?11.2‰ to?9.3‰ for δ18O with δ values increasing downstream. The isotopic signatures of the adjacent tributaries (the Tisza, the Sava and the Velika Morava) sampled at the locations close to their confluence with the Danube (Titel, Ostru?nica and Ljubi?evski most, respectively) just about the time of the campaign were enriched (?67‰ and?63‰ for δ2H, and?9.3‰ and?8.9‰ for δ18O) with respect to the Danube water because of their catchment effects. Hydrogen and oxygen stable isotope values were used in combination with measured physico-chemical and biological parameters to trace hydrological and transport processes in these river systems. The mixing relationships between the Danube main stream and its tributaries were estimated using the mass balance for isotopic composition and electrical conductivity as conservative parameters. Evidence of an incomplete mixing process at the ?enta location, 8 km below the confluence of the Tisza river, with its participation of 88% was shown by its oxygen-18 content. The correlations between river water isotope composition and physico-chemical and biological parameters are discussed.  相似文献   

5.
Carbon and nitrogen stable isotope ratios were measured in hair samples of the Asiatic black bear (Ursus thibetanus) inhabiting the Northern Japanese Alps (NJA) (n?=?20) and the periphery of Nagano City (NC) (n?=?6), in Nagano Prefecture, Japan. The hair of NJA bears, which did not have access to anthropogenic foods, showed lower values of δ13C and δ15N than that of NC bears which had access to garbage and corn fields, especially during the summer. These results reflect somewhat differing diets between the NJA and NC bears. We attempted to assess the feeding history during the hair growth cycle using the growth section analysis method. Each hair sample had been cut into 3?mm lengths from root to tip, labeled, and analyzed along the hair growth. We measured the carbon and nitrogen stable isotope ratios of each 3?mm length of hair sample from one NC bear which had been killed while raiding a corn field. The sections showed wide ranges of isotope ratios, from ?23.2‰ to ?14.6‰ for δ13C, and from 0.3‰ to 4.6‰ for δ15N. It was shown that the diet of this bear shifted dramatically from principally C3 plants to more C4 plants and to foods of animal origin. An analysis of the whole hair reflects just the average feeding habit during hair growth, but the present method can trace its diet history. This method can contribute to obtain precise ecological information of wildlife.  相似文献   

6.
Abstract

The isotopic compositions of biogenic carbon dioxide and methane from different sites were investigated. The δ13C values of methane vary mainly between ?55‰ and ?75‰ whereas δ13C values of carbon dioxide were found from about + 11‰ to ?23‰. Especially the latter ones are not so typical for microbial gases. The different sites don't vary over the whole scales but form certain groups. Secondary effects like diffusion change the δ values of both components in an even more negative direction, while oxidation processes near the surface result in more positive δ13C values for methane and very negative δ13C values for carbon dioxide.  相似文献   

7.
Ontogenetic niche shifts in diet are a consequence of changes in body size or resource partitioning between age classes. To better resolve the feeding patterns of the Japanese scallop Mizuhopecten yessoensis, we examined the relative importance of age and size in the diet of this species using stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) from 2006 to 2009. Contribution of food sources was quantified using an isotope mixing model by comparing the muscle tissue isotope ratios to those of suspended particulate organic matter (SPOM) and their zooplankton prey (e.g. micro- and meso-zooplankton). Unlike the δ13C values, which remained constant with age and size, muscle δ15N values were more positively correlated with age accounting for 69?% of variations than size with only 46?%. Increasing 15N values with age suggested that shifts in diet from SPOM to micro- and meso-zooplankton occurred during ontogeny in M. yessoensis. Results of the isotope mixing model indicated that SPOM contribution to scallop’s diet decreased from 68 to 8?% while those of zooplankton increased from 15 to 50?% with increasing age. This study concludes that age-related dietary shift explains the enrichment of 15N, as a result of predation on zooplankton by M. yessoensis.  相似文献   

8.
The stable isotopic compositions of all major daily rain fall samples (n?=?113) collected from Kozhikode station in Kerala, India, for the year 2010 representing the pre-monsoon, southwest and northeast monsoon seasons are examined. The isotopic variations δ18O, δ2H and d-excess in daily rainfall ranged from δ18O: ?4.4 to 2?‰, δ2H: ?25.3 to 13.8?‰, and d-excess: ?2.4 to 15.3?‰; δ18O: ?9.7 to ?0.6?‰, δ2H: ?61.7 to 5.3?‰, and d-excess 5.8 to 17.4?‰; δ18O ?11.3 to ?1.4?‰, δ2H: ?75.3 to 0.9?‰, and d-excess: 8.8 to 21.3?‰ during the pre-, southwest and northeast monsoon periods, respectively. Thus, daily rainfall events during two monsoon periods had a distinct range of isotopic variations. The daily rain events within the two monsoon seasons also exhibited periodic variations. The isotopic composition of rain events during pre-monsoon and a few low-intensity events during the southwest monsoon period had imprints of secondary evaporation. This study analysing the stable isotopic characteristics of individual rain events in southern India, which is influenced by dual monsoon rainfall, will aid in a better understanding of its mechanism.  相似文献   

9.
Laboratory experiments are useful for estimating the carbon and nitrogen isotope discrimination factors and turnover rates that are critical for drawing field-based inferences on consumer diets using stable isotopes. Although the utility of these discrimination factors is widely recognized, work in terrestrial systems has largely been limited to studies involving mammals and birds. In contrast, scant attention has been paid to the application of isotopic techniques to reptiles, despite their broad diversity in terms of numbers of species as well as their trophic roles. Here we estimate carbon and nitrogen isotope discrimination factors and turnover for the tree lizard (Urosaurus ornatus) using a diet-switch experiment. Lizards were collected from a C4-dominated grassland and then switched to C3-based diet (crickets) in the laboratory. We estimated discrimination by lizard claw tissue as Δ13C?=?1.2?±?0.1?‰ for carbon and Δ15N?=?0.7?±?0.1?‰ (mean?±?1 SE) for nitrogen, with 95?% turnover occurring after ~15.5 days. These estimates should be appropriate for use in trophic studies of U. ornatus, and possibly other related small-bodied insectivorous lizards.  相似文献   

10.
Natural nitrogen isotopic composition (δ15N) of suspended particulate organic matter (POM) and nitrogen fixation rates via 15N2 assay were measured in surface waters along 120° E from 30° N to 30° S in the Asian marginal seas (the East/South China Seas and the Sulu/Celebes/Java Seas) and the northeastern Indian Ocean in November–December 2005 and March 2006. The POM δ15N values ranged from?1.8 to 12.2‰ with an average of 3.6‰ and showed a decreasing trend towards the equator in both hemispheres. In parallel, the measured N2 fixation rates showed an increase from the subtropical to the tropical seas. This implies that a higher contribution of 15N-depleted POM was derived from enhanced N2 fixation. Water temperature and the stability of water column were partly responsible for the observed variations in nitrogen fixation. The large-scale spatial variations in suspended POM δ15N and N2 fixation rates suggest that the suspended POM δ15N may be a potential indicator of nitrogen fixation in surface waters in tropical/subtropical seas.  相似文献   

11.
Abstract

Locust nymphs were raised from hatching to adult locusts on either seedling wheat (C3) or maize (C4), to determine whether relative enrichments/depletions of 15N and 13C within body tissues are influenced by diet. The maize contained less hexose sugars and protein per gram than wheat.

The isotopic spacing between the food and the whole insect was found to differ between the two diets. The lower quality maize diet showed an overall +5.1‰ enrichment in δ15N compared to + 2.8‰ for wheat, possibly due to increased fractionation due to protein recycling.

The maize diet resulted in increased depletion in lipid and trehalose and depletion in chitin relative to diet. The results for both δ15N and δ13C suggest that substrate recycling was occurring on the low quality maize diet. Therefore diet quality determines the enrichment/depletion in δ15N and δ13C within organisms.  相似文献   

12.
We have applied both palynological and carbon and nitrogen isotopic analyses of PM10 (particulate matter with a diameter of 10 μm or less) to trace its origin and to assess the anthropogenic impact for the area under study. The PM10 samples were collected in Wroc?aw (SW Poland) by the Regional Inspectorate for Environment Protection during the year 2007. The usefulness of the palynological observations in the case of PM10 is much lower than that for total suspended particles due to the resolution of absorbed particles, but is still helpful for distinguishing C3/C4 plants that indicate long-distance transport of pollutants. The δ13C(PM10) values varied seasonally from?26.9 to?25.1‰. The δ15N(PM10) values showed chaotic fluctuations and varied from 5.0 to 13.7‰. Our results indicated that during the heating period, the PM10 particles in Wroc?aw are derived mainly from local home heaters, whereas in the growing period, PM10 particles are derived from local transport and are partially generated by the industrial application of coal combustion outside the city of Wroc?aw.  相似文献   

13.
When a diet switch results in a change in dietary isotopic values, isotope ratios of the consumer's tissues will change until a new equilibrium is reached. This change is generally best described by an exponential decay curve. Indeed, after a diet switch in captive red knot shorebirds (Calidris canutus islandica), the depletion of 13C in both blood cells and plasma followed an exponential decay curve. Surprisingly, the diet switch with a dietary 15N/14N ratio (δ15N) change from 11.4 to 8.8 ‰ had little effect on δ15N in the same tissues. The diet-plasma and diet-cellular discrimination factors of 15N with the initial diet were very low (0.5 and 0.2 ‰, respectively). δ15N in blood cells and plasma decreased linearly with increasing body mass, explaining about 40 % of the variation in δ15N. δ15N in plasma also decreased with increasing body-mass change (r 2=.07). This suggests that the unusual variation in δ15N with time after the diet switch was due to interferences with simultaneous changes in body-protein turnover.  相似文献   

14.
Overgrazing often lowers species richness and productivity of grassland communities. For Mongolian grassland ecosystems, a lack of detailed information about food-web structures makes it difficult to predict the effects of overgrazing on species diversity and community composition. We analysed the δ13C and δ15N signatures of herbaceous plants, arthropods (grouped by feeding habit), wild and domestic mammals, and humans in central Mongolia to understand the predominant food-web pathways in this grassland ecosystem. The δ13C and δ15N values of mammals showed little variation within species, but varied considerably with slope position for arthropods. The apparent isotopic discrimination between body tissue and hair of mammals was estimated as 2.0 ‰ for δ13C and 2.1 ‰ for δ15N, which was large enough to cause overestimation of the trophic level of mammals if not taken into account when using hair samples to measure isotopic enrichment.  相似文献   

15.
High and fluctuating salinity is characteristic for coastal salt marshes, which strongly affect the physiology of halophytes consequently resulting in changes in stable isotope distribution. The natural abundance of stable isotopes (δ13C and δ15N) of the halophyte plant Salicornia brachiata and physico-chemical characteristics of soils were analysed in order to investigate the relationship of stable isotope distribution in different populations in a growing period in the coastal area of Gujarat, India. Aboveground and belowground biomass of S. brachiata was collected from six different populations at five times (September 2014, November 2014, January 2015, March 2015 and May 2015). The δ13C values in aboveground (?30.8 to ?23.6?‰, average: ?26.6?±?0.4?‰) and belowground biomass (?30.0 to ?23.1?‰, average: ?26.3?±?0.4?‰) were similar. The δ13C values were positively correlated with soil salinity and Na concentration, and negatively correlated with soil mineral nitrogen. The δ15N values of aboveground (6.7–16.1?‰, average: 9.6?±?0.4?‰) were comparatively higher than belowground biomass (5.4–13.2?‰, average: 7.8?±?0.3?‰). The δ15N values were negatively correlated with soil available P. We conclude that the variation in δ13C values of S. brachiata was possibly caused by soil salinity (associated Na content) and N limitation which demonstrates the potential of δ13C as an indicator of stress in plants.  相似文献   

16.
The Tanour spring is one of the several karst springs located in the northern part of Jordan. Water samples from the Tanour spring and precipitation were collected in the area of Ajloun in NW Jordan for the analysis of stable oxygen and hydrogen isotopes to evaluate the spring response to precipitation events. Rainwater and snow samples were collected from different elevations during winters of 2013–2014 and 2014–2015. In addition, spring samples were collected between December 2014 and March 2015. δ18O values in rainwater vary from ?3.26 to ?17.34?‰ (average: ?7.84?±?3.23?‰), while δ2H values range between ?4.4 and ?110.4?‰ (average: ?35.7?±?25.0?‰). Deuterium excess ranges from 17.8 to 34.1?‰ (average: 27.1?±?4.0?‰). The Local Meteoric Water Line for the study area was calculated to be δ2H?=?7.66*δ18O?+?24.43 (R2?=?0.98). Pre-event spring discharge showed variation in δ18O (range ?6.29 to ?7.17?‰; average ?6.58?±?0.19?‰) and δ2H values (range ?28.8 to ?32.7?‰; average: ?30.5?±?1.0?‰). In contrast, δ18O and δ2H rapidly changed to more negative values during rainfall and snowmelt events and persisted for several days before returning to background values. Spring water temperature, spring discharge, and turbidity followed the trend in isotopic composition during and after the precipitation events. The rapid change in the isotopic composition, spring discharge, water temperature, and turbidity in response to recharge events is related to fast water travel times and low storage capacity in the conduit system of the karst aquifer. Based on the changes in the isotopic composition of spring water after the precipitation events, the water travel time in the aquifer is in the order of 5–11 days.  相似文献   

17.
The thermal fluids vented over Eskisehir province have been investigated for their origin and to estimate the geothermal potential of the area. Thermal waters as well as bubbling and dissolved gases were collected and analysed for their chemical and isotopic features. Their isotopic composition varies in the range from ?11.5 to ?7.7?‰ for δ18O, ?84 and ?57?‰ for δ2H, and 0–7.2 TU for tritium. The gases (bubbling and dissolved) are mostly N2-dominated with a significant amount of CO2. The helium isotopic ratios are in the range of 0.2–0.66?R/Rac, indicate remarkable mantle-He contribution ranging between 2 and 10?% in the whole study area. Considering the estimated geothermal gradient about three times higher than the normal gradient, and the reservoir temperatures estimated to be between 50 and 100?°C using quartz and chalcedony geothermometers, a circulation model was built where possible mixing with shallow waters cool down the uprising geothermal fluids.  相似文献   

18.
This paper presents the results of hydrological, physicochemical, biological, and isotopic investigations of the Danube River along the stretch through Serbian territory conducted during four campaigns in September and November 2007, September 2008 and April 2009. The stable isotope values exhibited significant changes both in the Danube (?10.7 to?9.5‰ for δ18O and?73.7 to?67.1 ‰ for δ2H) and in its tributaries (?9.1 to?8.5‰ for δ18O and?69.4 to?59.4‰ for δ2H) depending on the time of survey, which could be partly attributed to the influences of seasonal effects. Results emphasise the dominant role of tributaries inflows from aquifers along the Danube. The very narrow range of δ13CPOC (from?28.9 to?27.4 ‰) was associated with relatively high C/N ratios (C/N>9), and together with δ15NTPN values, the date suggested that, in early spring, a major fraction of particulate organic matter was derived from allochthonous matter. An orthogonal varimax rotation of the principal components analysis identified four latent factors (‘mineral related’, ‘biological’, ‘hardness’, and ‘soil inlets’) which are responsible for the data structure covering 79% of the observed variations among the variables studied. A reliable grouping of samples with respect to the season was found.  相似文献   

19.
The variation of the natural 15N abundance is often used to evaluate the origin of nitrogen or the pathways of N input into ecosystems. We tried to use this approach to assess the main input pathways of nitrogen into the sand dune area of the north-western Negev Desert (Israel). The following two pathways are the main sources for nitrogen input into the system:
  1. Biological fixation of atmospheric nitrogen by cyanobacteria present in biological crusts and by N2-fixing vascular plants (e.g. the shrub Retama raetam);

  2. Atmospheric input of nitrogen by wet deposition with rainfall, dry deposition of dust containing N compounds, and gaseous deposition.

Samples were taken from selected environmental compartments such as biological crusts, sand underneath these crusts (down to a depth of 90?cm), N2-fixing and non-N2-fixing plants, atmospheric bulk deposition as well as soil from arable land north of the sandy area in three field campaigns in March 1998, 1999 and 2000. The δ15N values measured were in the following ranges: grass ?2.5‰ to +1.5‰; R. reatam: +0.5‰ to +4.5‰; non-N2-fixing shrubs +1‰ to +7‰; sand beneath the biological crusts +4‰ to +20‰ (soil depth 2–90?cm); and arable land to the north up to 10‰. Thus, the natural 15N abundance of the different N pools varies significantly. Accordingly, it should be feasible to assess different input pathways from the various 15N abundances of nitrogen. For example, the biological N fixation rates of the Fabaceae shrub R. reatam from the 15N abundances measured were calculated to be 46–86% of biomass N derived from the atmosphere. The biological crusts themselves generally show slight negative 15N values (?3‰ to ?0.5‰), which can be explained by biological N fixation. However, areas with a high share of lichens, which are unable to fix atmospheric nitrogen, show very negative values down to ?10‰. The atmospheric N bulk deposition, which amounts to 1.9–3.8?kg?N/ha?yr, has a 15N abundance between 4.4‰ and 11.6‰ and is likely to be caused by dust from the arable land to the north. Thus, it cannot be responsible for the very negative values of lichens measured either. There must be an additional N input from the atmosphere with negative δ15N values, e.g. gaseous N forms (NO x , NH3). To explain these conflicting findings, detailed information is still needed on the wet, particulate and gaseous atmospheric deposition of nitrogen.  相似文献   

20.
Tracers can be used to monitor emissions of leachate from landfills in order to detect hydrological pathways and to evaluate environmental pollution. We investigated the stable carbon isotope ratio (δ13C–Σ CO 2) in dissolved inorganic carbon and tritium (3H) in water, in addition to the tracers of pollution commonly found in relatively high concentrations in leachate, such as chloride (Cl), organic matter (COD), nitrogen (total and NH4–N), iron (Fe), electrical conductivity (EC) and pH. The sampling was performed at seven landfills in the south-eastern part of Norway during a period of 5 years. The objective was to evaluate the potential for tracing leachate in the environment with emphasis on groundwater pollution. By measuring the δ13C–Σ CO 2 in leachates, groundwaters and surface waters, the influence of leachate can be identified. The value of δ13C–Σ CO 2 varied from?5.5 to 25.9 ‰ in leachate, from?25.4 to 14.7 ‰ in groundwater and from?19.7 to?13.1 ‰ in creeks. A comparison of the carbon isotope ratio with COD, EC and the concentrations of total and NH 4–N, Cl and Fe showed that δ13C–Σ CO 2 is a good tracer for leachate due to higher sensitivity compared to other parameters. The mean concentrations of all the studied parameters were higher in the leachate samples; however, only the carbon isotope ratio showed significant differences between all the groups with strong and middle pollution and samples with low pollution, showing that it can be used as a convenient tracer for leachate in groundwater and surface water. The carbon isotope ratio showed strong correlation between nitrogen, EC and bicarbonate, but not with pH. Tritium was only sporadically found in measureable concentrations and is not considered as a suitable tracer at the sampled locations.  相似文献   

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