scholarly journals Isotopic Signatures (δ13C and δ15N) and Characteristics of Two Wetland Soils in Lesotho, Southern Africa

2019 ◽  
Author(s):  
Olaleye Adesola Olutayo
Keyword(s):  
Southern Africa ◽  
Wetland Soils ◽  
Δ13c And Δ15n ◽  
Isotopic Signatures

scholarly journals C / N ratio, stable isotope (δ<sup>13</sup>C, δ<sup>15</sup>N), and <i>n</i>-alkane patterns of bryophytes along hydrological gradients of low-centred polygon of the Siberian Arctic

2016 ◽  
Author(s):  
Romy Zibulski ◽  
Felix Wesener ◽  
Heinz Wilkes ◽  
Birgit Plessen ◽  
Luidmila A. Pestryakova ◽  
...  
Keyword(s):  
Water Level ◽  
Isotopic Signature ◽  
The Arctic ◽  
Specific Level ◽  
Δ13c And Δ15n ◽  
Lena River ◽  
Isotopic Signatures ◽  
Microbial Symbiosis ◽  
The Stability ◽  
The Individual

Abstract. Mosses are a major component of the arctic vegetation, particularly of wetlands. We present C / N ratio, δ13C and δ15N data of 400 moss samples belonging to 10 species that were collected along hydrological gradients within polygonal mires located on the southern Taymyr Peninsula and the Lena River delta in northern Siberia. Additionally, n alkane patterns of six of these taxa were investigated. The aim of the study is to see whether the inter- and intra-specific differences in biochemical and isotopic signatures are indicative of habitat with particular respect to water-level. Overall, we find high variability in all investigated parameters. The C / N ratios range between 15.4 and 70.4 (median: 42.9) and show large variations at intra-specific level. However, species preferring a dry habitat (xero-mesophilic mosses) show higher C / N ratios than those preferring a wet habitat (meso-hygrophilic mosses). We assume that this mainly originates from the association of mosses from wet habitats with microorganisms which supply them with nitrogen. Furthermore, because of the stability provided by water, they do not need to invest in a sturdy stem-structure and accordingly have lower C contents in their biomass. The δ13C values range between −37.0 and 22.5 ‰ (median = −27.8 ‰). The δ15N values range between −6.59 and +1.69 ‰ (median = 2.17 ‰).We find differences in δ13C and δ15N signatures between both habitat types and, for some species of the meso-hygrophilic group, a significant relation between the individual habitat water-level and isotopic signature was inferred as a function of microbial symbiosis. The n alkane distribution also shows differences primarily between xero-mesophilic and meso-hygrophilic mosses, i.e. having a dominance of n-alkanes with long (n-C29, n-C31) and intermediate chain lengths (n-C25), respectively. Overall, our results reveal that biochemical and isotopic signals of certain moss taxa from polygonal wetlands are characteristic of their habitat and can thus be used in (palaeo-)environmental studies.

scholarly journals Intra-Body Variations of Stable Isotope Ratios (δ13C, δ15N) and Influence of Storage Methods in Aquatic and Post-Aquatic Stages of the Common Toad, Bufo bufo

Water ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 2544
Author(s):  
Andrey N. Reshetnikov ◽  
Daniil I. Korobushkin
Keyword(s):  
Isotope Composition ◽  
Bufo Bufo ◽  
Common Toad ◽  
Δ13c And Δ15n ◽  
Isotopic Signatures ◽  
The Common ◽  
Two Stages ◽  
Method Factors ◽  
Toad Bufo ◽  
Toad Bufo Bufo

Isotopic signatures of carbon and nitrogen are widely used for analysis of the structure of food webs in aquatic ecosystems. The study of animals raises a number of methodological questions, including choice of representative tissues and organs for sampling as well as storage of the studied organisms. Furthermore, the impacts of preservation methods can be tissue-specific, age-specific, and even taxon-specific; thus, studies of these impacts on particular taxa are necessary. We focused on the C and N isotope composition of the common toad (Bufo bufo), one of the most widespread European anuran amphibians. We hypothesized that its different tissues and organs may vary in isotopic composition, and ethanol and freezing may have different effects on isotopic values. Our results showed that both “tissue” and “storage method” factors significantly affected the δ13C values of tadpoles and postmetamorphic juveniles, whereas only the “tissue” factor had a significant effect on the δ15N values. The two stages, tadpoles and postmetamorphs, should be analyzed separately despite the brief postmetamorphic period of the juveniles. The skin, legs, muscles, and tail in tadpoles and legs, muscles and heart in juveniles can be used for δ13C and δ15N analysis regardless of the method of storage. The results will serve for the optimization of future study designs in isotopic ecology.

scholarly journals Major Sources of Organic Matter in a Complex Coral Reef Lagoon: Identification from Isotopic Signatures (δ13C and δ15N)

PLoS ONE ◽  
2015 ◽  
Vol 10 (7) ◽  
pp. e0131555 ◽  
Author(s):  
Marine J. Briand ◽  
Xavier Bonnet ◽  
Claire Goiran ◽  
Gaël Guillou ◽  
Yves Letourneur
Keyword(s):  
Organic Matter ◽  
Coral Reef ◽  
Δ13c And Δ15n ◽  
Isotopic Signatures ◽  
Reef Lagoon ◽  
Coral Reef Lagoon

Diet of the pulmonate gastropod Onchidella nigricans in the intertidal rocky shore, New Zealand

2009 ◽  
Vol 59 (2) ◽  
pp. 231-240 ◽  
Author(s):  
Andrea Alfaro
Keyword(s):  
Stable Isotopes ◽  
New Zealand ◽  
Algal Species ◽  
Rocky Intertidal ◽  
Coralline Algae ◽  
Gut Contents ◽  
Bare Rock ◽  
Generalist Herbivore ◽  
Δ13c And Δ15n ◽  
Isotopic Signatures

AbstractGut content analyses and stable isotopes (δ13C and δ15N) were used to investigate the food consumption and assimilation of the pulmonate, Onchidella nigricans, within a rocky intertidal platform at Waiwera, northern New Zealand. Analyses of gut contents indicate that this species is a generalist herbivore, which may consume a variety of micro- and macro-algae, although small zooplankton may be ingested, when present. Gut contents of individuals collected from different intertidal habitats (bare rock, Hormosira banksii, green filaments, and coralline algae) reflected the dominant algal species within each habitat, suggesting that food availability does not restrict the grazer's distribution across its range. The radular morphology and small size of this gastropod also support the notion that O. nigricans is a non-selective microphagous feeder. However, stable isotopes on O. nigricans from the four habitats and the dominant algal food types indicate a strong assimilation preference for microalgae. The δ13C values (-15 to -13‰) of O. nigricans were consistent with signatures for intertidal grazers, but δ15N values (8 to 9‰) were relatively high, which may indicate the presence of bacteria and microfaunal detritus in the diet. Clusters of isotopic signatures of individuals from different habitats suggest feeding preferences, which also may be attributed to differences in detrital and bacterial consumption. This study illustrates the importance of using parallel techniques in diet studies.

scholarly journals Application of Effective Day Degrees in the Assessment of Stable Isotope Patterns in Developing Seahorses under Different Temperatures

Animals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1571 ◽  
Author(s):  
Sonia Valladares ◽  
Miquel Planas
Keyword(s):  
Stable Isotope ◽  
Abiotic Factors ◽  
Experimental Period ◽  
Δ13c And Δ15n ◽  
Isotopic Signatures ◽  
Developmental Progress ◽  
Temperature Regimes ◽  
Temperature Levels ◽  
Food Assimilation ◽  
Chronological Time

Relations between nutrient assimilation and growth rate in fishes may vary with abiotic factors such as temperature. The effects of feeding status, ontogeny and temperature regimes (15, 18 and 21 °C) on stable isotope (δ13C and δ15N) patterns were assessed in juveniles of the seahorse Hippocampus guttulatus. The use of effective day degrees (D°eff), day degrees (D°) and chronological time (age) were compared as development progress indices. Newborn seahorses were maintained at three temperature levels both deprived of food (5 days) or fed (30 days) on copepods or/and Artemia. Isotopic signatures in fed seahorses clearly differed from those in unfed juveniles. Temperature had a significant effect on δ13C values in fed juveniles throughout the experimental period. δ15N values also varied significantly with age, but not with temperature level. Faster growth and food assimilation in seahorses held at 18 and 21 °C were supported by faster variations in isotopic values. Our findings demonstrate that effective day degrees should be preferred over chronological time as index of developmental progress in temperature fluctuating scenarios or for comparative studios.

Identification of local populations of Lake Biwa catfish Silurus biwaensis in Japan on the basis of δ13C and δ15N analyses

1999 ◽  
Vol 77 (2) ◽  
pp. 258-266 ◽  
Author(s):  
Noriyuki Takai ◽  
Wataru Sakamoto
Keyword(s):  
Stable Isotope ◽  
Lake Biwa ◽  
Local Population ◽  
Isotope Analysis ◽  
Lepomis Macrochirus ◽  
Δ13c And Δ15n ◽  
Eastern Area ◽  
Isotopic Signatures ◽  
Local Populations ◽  
Ultrasonic Tracking

Carbon and nitrogen stable isotope ratios were used to examine the mixing of adult Lake Biwa catfish, Silurus biwaensis, in different areas of the lake and to identify the local populations. The isotopic signatures of its prey, the bluegill, Lepomis macrochirus, were also examined as indicators of each local food web. We analyzed 141 Lake Biwa catfish and 60 bluegills captured in the lake. The differences in δ13C values indicated that the two groups of catfish captured in the northern- and the southern-most spawning areas did not mix with each other frequently and were thus identified as local populations. The catfish captured in the mid-eastern area, where no spawning ground was found, were considered to be a group of migrators from the southernmost area, not a local population. These results are consistent with those obtained using ultrasonic tracking. It was therefore clearly demonstrated that stable isotope analysis is useful for identifying local populations of aquatic animals.

scholarly journals Stable Isotope Analyses of Multiple Tissues of Great Shearwaters (Ardenna Gravis) Reveals Long-Term Dietary Stability, Short-Term Changes in Diet, and Can be Used as a Tool to Monitor Food Webs

Diversity ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 163 ◽  
Author(s):  
Hong ◽  
Wiley ◽  
Powers ◽  
Michener ◽  
Kaufman ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Food Web ◽  
Food Webs ◽  
Trophic Level ◽  
Isotope Analysis ◽  
Diet Shift ◽  
Turnover Rates ◽  
Δ13c And Δ15n ◽  
Isotopic Signatures ◽  
Over Time

The great shearwater (Ardenna gravis) is a common pelagic bird with a distribution that spans almost the entire Atlantic basin, which in conjunction with its relatively high abundance, makes great shearwaters an effective bio indicator. We compared δ13C and δ15N values from the feathers, red blood cells (RBCs), and plasma of great shearwaters collected in 2014 and 2015 from the waters off Massachusetts and Cape Cod. The δ13C and δ15N values of RBCs were quite constant between sampling periods and years, suggesting a generally stable food web over that time period. However, the δ13C of plasma indicates a small seasonal change in diet between July and September for both years, with plasma δ15N values suggesting a slight increase in trophic level late in summer. Comparison of the δ15N of RBCs and plasma indicates that great shearwaters experienced a diet shift during the first few weeks of summer 2014, but not in 2015. Comparisons with other studies suggest that these shearwaters feed at a lower trophic level than great shearwaters sampled in the Bay of Fundy and that there is a decrease in δ13C with increasing latitude, which could indicate a more pelagic diet in northern waters. Stable isotope analysis of the sixth primary feathers provided evidence that these feathers are molted in the Northern Hemisphere and that the diet of great shearwaters shortly after arrival was different in 2014 and 2015. This study demonstrates that within species comparisons of tissue isotopic signatures over time and comparisons of isotopic signatures of tissues with different turnover rates, can detect changes in diet and be used as a tool to monitor for changes in marine food webs over time and space. The relevant signals remain informative even in the absence of species-specific data on tissue-diet discrimination factors, tissue turnover rates, or knowledge of dietary components and their stable isotopic signatures, suggesting dietary changes indicative of a corresponding change in the food web.

scholarly journals Diet assessments as a tool to control invasive species: comparison between Monk and Rose-ringed parakeets with stable isotopes

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
N A Borray-Escalante ◽  
D Mazzoni ◽  
A Ortega-Segalerva ◽  
L Arroyo ◽  
V Morera-Pujol ◽  
...  
Keyword(s):  
Invasive Species ◽  
Isotope Analysis ◽  
Control Measures ◽  
Food Sources ◽  
Effective Control ◽  
Limiting Factor ◽  
Δ13c And Δ15n ◽  
Isotopic Signatures ◽  
Monk Parakeet ◽  
Anthropogenic Food

Abstract Food is a main limiting factor for most populations. As a consequence, knowledge about the diet of invasive alien species determines the design of control measures. The Monk and Rose-ringed parakeets are two typical species of successful invasive parrots that are highly appreciated by people. Although some observations suggest that Monk parakeets rely on a higher percentage of anthropogenic food than Rose-ringed parakeets, no detailed quantitative data is available. The aim of this study was to compare the diet of the two parakeets using stable isotope analysis (SIA). We performed SIA of carbon and nitrogen in feathers collected in Barcelona, Spain. We also measured isotopic ratios for potential food sources. We reconstructed the diet of parakeets using Bayesian mixing models. The two species differed in the isotopic signatures of their feathers for both δ13C and δ15N. Diet reconstruction showed that Monk parakeets feed mainly on anthropogenic food (41.7%), herbaceous plants (26.9%) and leaves/seeds (22.2%), while Rose-ringed parakeets feed mainly on flowers/fruits (44.1%), anthropogenic food provided in the trap located at the museum (32.4%) and leaves/seeds (23.1%). The more detailed information we can obtain from the diet of these species is useful to develop more effective control measures for their populations. The Monk parakeet may be more susceptible to control through education local residents, given the greater use of anthropogenic food in this species compared to Rose-ringed parakeet. Our conclusions also indicate that SIA is a powerful tool in providing crucial information about the diet and informing measures to control invasive species.

Inherent variation in carbon and nitrogen isotopic assimilation in the freshwater macro-invertebrate Cherax destructor

2016 ◽  
Vol 67 (12) ◽  
pp. 1928 ◽  
Author(s):  
Debashish Mazumder ◽  
Li Wen ◽  
Mathew P. Johansen ◽  
Tsuyoshi Kobayashi ◽  
Neil Saintilan
Keyword(s):  
Trophic Ecology ◽  
Individual Variability ◽  
Δ13c And Δ15n ◽  
Isotopic Signatures ◽  
Carbon And Nitrogen ◽  
Source Selection ◽  
Cherax Destructor ◽  
Specific Variation ◽  
The Individual ◽  
Diet Source

Individual variability in diet source selection has often been cited as the main factor for intra-specific variation of isotopic signatures among food-web consumers. We conducted a laboratory study to test how well the individual variability of the δ13C and δ15N ratios in the muscle of an omnivore consumer (yabby: Cherax destructor) corresponded to the variability of various diet types and diet combinations. We found that C. destructor muscle isotope signatures varied in concert with the composition of single-source diets, and that this variability was low. However, when fed the same proportional mixture of multiple diet sources, comparatively high isotopic variability was observed among specimens. Results suggest that a substantial component of isotopic variability in wild populations may be owing to inherent differences in uptake, absorption, and sequestration among individuals, which is distinct from behaviourally driven individualised diet selection. Considering the potential of such individual variability in assimilation to be present in many different consumer populations, we suggest further testing for a range of species and inclusion of this source of variation, for interpretation of isotopic data for trophic ecology.

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