scholarly journals Preservation in 70% ethanol solution does not affect δ13C and δ15N values of reindeer blood samples – relevance for stable isotope studies of diet

Rangifer ◽  
2008 ◽  
Vol 28 (1) ◽  
pp. 9 ◽  
Author(s):  
Duncan J. Halley ◽  
Masao Minagawa ◽  
Mauri Nieminen ◽  
Eldar Gaare
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Efficient Method ◽  
Isotope Analysis ◽  
Ethanol Solution ◽  
Δ13c And Δ15n ◽  
Blood Samples ◽  
Isotope Studies ◽  
Whole Blood Samples ◽  
Chloroform Methanol

We compared duplicate samples of whole blood samples from 18 reindeer that were preserved either by immediate freezing or by immersion in 70 % ethanol. All samples were dried at 60 °C, powdered, treated with 1:1 chloroform: methanol, and dried again before isotope analysis. There were no differences in the values of δ13C and δ15N between the methods of preservation. Isotopic differences were absolutely small (δ13C = 0.1±0.10/00; δ15N=0.2±0.20/00), random in direction, and within the limits of analytical precision for the mass spectrometer. Preservation in ethanol thus appears to be an effective and efficient method for preserving blood samples for stable isotope analysis under field conditions. Abstract in Norwegian / Sammendrag:Konservering av blodprøver fra rein i 70% etanolløsning påvirker ikke verdiene av δ13C and δ15N–verdiene og er en fullgod metode for analyse av stabile isotoperVi sammenlignet to og to prøver av blodprøver fra 18 reinsdyr. Prøvene var enten konservert ved umiddelbar frysing eller ved bruk av 70% etanol. Alle prøver ble tørket ved 60 °C, pulverisert og behandlet med kloroform:metanol i forholdet 1:1. Til slutt ble de tørket på nytt før gjennomføring av isotopanalysen. Vi fant ingen forskjell i verdiene av δ13C and δ15N mellom de to konserveringsmetodene. I absolutte verdier var isotopforskjellene små (δ13C = 0.1±0.1 0/00; δ15N=0.2±0.2 0/00). Forskjellene var tilfeldige og innenfor grensene for massespektrometerets presisjon. Bruk av etanol framstår som en effektiv og fullgod metode til konservering av blodprøver for analyse av stabile isotoper under feltforhold.

Stable isotope analysis reveals partitioning in prey use by Kajikia audax (Istiophoridae), Thunnus albacares, Katsuwonus pelamis, and Auxis spp. (Scombridae) in the Eastern Tropical Pacific of Ecuador

2021 ◽  
Vol 19 (4) ◽  
Author(s):  
Rigoberto Rosas-Luis ◽  
Nancy Cabanillas-Terán ◽  
Carmen A. Villegas-Sánchez
Keyword(s):  
Stable Isotope ◽  
Food Web ◽  
Stable Isotope Analysis ◽  
Trophic Ecology ◽  
Isotope Analysis ◽  
Middle Level ◽  
Food Sources ◽  
Thunnus Albacares ◽  
Katsuwonus Pelamis ◽  
Δ13c And Δ15n

Abstract Kajikia audax, Thunnus albacares, Katsuwonus pelamis, and Auxis spp. occupy high and middle-level trophic positions in the food web. They represent important sources for fisheries in Ecuador. Despite their ecological and economic importance, studies on pelagic species in Ecuador are scarce. This study uses stable isotope analysis to assess the trophic ecology of these species, and to determine the contribution of prey to the predator tissue. Isotope data was used to test the hypothesis that medium-sized pelagic fish species have higher δ15N values than those of the prey they consumed, and that there is no overlap between their δ13C and δ15N values. Results showed higher δ15N values for K. audax, followed by T. albacares, Auxis spp. and K. pelamis, which indicates that the highest position in this food web is occupied by K. audax. The stable isotope Bayesian ellipses demonstrated that on a long time-scale, these species do not compete for food sources. Moreover, δ15N values were different between species and they decreased with a decrease in predator size.

Trophic relationships of the platypus: insights from stable isotope and cheek pouch dietary analyses

2016 ◽  
Vol 67 (8) ◽  
pp. 1196 ◽  
Author(s):  
Melissa Klamt ◽  
Jenny A. Davis ◽  
Ross M. Thompson ◽  
Richard Marchant ◽  
Tom R. Grant
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Isotope Analysis ◽  
Trophic Relationships ◽  
Cheek Pouch ◽  
Insect Larvae ◽  
Top Down ◽  
Δ13c And Δ15n ◽  
Eastern Australia ◽  
Wide Range

The unique Australian monotreme, the platypus (Ornithorhynchus anatinus) potentially exerts a strong top-down influence on riverine food webs in eastern Australia. However, despite considerable interest in the evolutionary history and physiology of the platypus, little is known of its trophic relationships. To address this lack of knowledge we used stable isotope analysis, in combination with the analysis of food items stored in cheek pouches, to determine its position in a typical riverine food web. This was the essential first step in the process of designing a larger study to investigate the relative importance of top-down and bottom-up effects in rivers where the platypus occurs. We found that platypuses were feeding on a wide range of benthic invertebrates, particularly insect larvae. The similarity of δ13C and δ15N values recorded for the platypus, a native fish (Galaxias sp.) and the exotic mosquitofish (Gambusia holbrooki) indicated dietary overlap and potential competition for the same resources. Although cheek pouch studies identify most of the major groups of prey organisms, the potential for contribution of the soft-bodied organisms such as larval dipterans, is suggested by stable isotope analysis, indicating that the use of both techniques will be important in future ecological investigations.

Stable isotope analysis reveals that humpback whales (Megaptera novaeangliae) primarily consume capelin (Mallotus villosus) in coastal Newfoundland, Canada

2021 ◽  
Author(s):  
Kelsey Johnson ◽  
Gail Davoren
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Isotope Analysis ◽  
Niche Overlap ◽  
Prey Type ◽  
Megaptera Novaeangliae ◽  
Humpback Whales ◽  
Mallotus Villosus ◽  
Δ13c And Δ15n ◽  
Capelin Mallotus Villosus

On the Newfoundland, Canada foraging ground, humpback whales (Megaptera novaeangliae (Borowski, 1781)) are found associated with a dominant forage fish species, capelin (Mallotus villosus (Müller, 1776), that experienced a population collapse in the early 1990s and has not recovered. Our primary goal was to reconstruct dietary proportions of humpback whales on their summer foraging grounds off the northeastern Newfoundland coast during July-August, 2016 and 2017 using a Bayesian stable isotope mixing model (MixSiar). Modelled dietary proportions were similar in both years, with capelin comprising ~90% of the diet. However, both δ13C and δ15N in humpback whale skin differed significantly between years, resulting in minimal dietary niche overlap (9%). Lipid-extracted and nonlipid-extracted skin samples were used to develop a lipid normalization equation: ∆13C = – 3.184 + 1.011(C:N). Overall, findings suggest that capelin is the primary prey type of humpback whales in coastal Newfoundland, despite the continued collapsed state of the capelin population. Findings also reiterate that dietary reconstruction from stable isotope analysis of cetacean skin can be misinterpreted without concurrently sampled isotopic ratios of potential prey types.

scholarly journals Stable isotope analysis of marine feeding signatures of Atlantic salmon in the North Atlantic

2009 ◽  
Vol 67 (1) ◽  
pp. 52-61 ◽  
Author(s):  
J. Brian Dempson ◽  
Victoria A. Braithwaite ◽  
Denis Doherty ◽  
Michael Power
Keyword(s):  
Stable Isotope ◽  
Atlantic Salmon ◽  
Stable Isotope Analysis ◽  
North Atlantic ◽  
C:N Ratio ◽  
Isotope Analysis ◽  
Unknown Origin ◽  
Δ13c And Δ15n ◽  
The North ◽  
The North Atlantic

Abstract Dempson, J. B., Braithwaite, V. A., Doherty, D., and Power, M. 2010. Stable isotope analysis of marine feeding signatures of Atlantic salmon in the North Atlantic. – ICES Journal of Marine Science, 67: 52–61. Differences in the marine feeding of three geographically distinct populations of Atlantic salmon (Salmo salar) in the North Atlantic (Conne River, Newfoundland; Koksoak River, Ungava Bay, Québec; River Erne, northwest Ireland) were examined using analyses of stable isotopes of carbon and nitrogen (δ13C and δ15N) and contrasted with isotope signatures obtained from a sample of salmon of unknown origin captured in the Labrador Sea. Although the overall range of δ13C and δ15N values (δ13C: from −22.42 to −19.37; δ15N: from 10.70 to 13.38) was similar to that reported by others, significant differences were found among populations and between different sea-age life-history groups. Reported differences in marine feeding between populations from the Northeast and Northwest Atlantic corroborated the stable isotope results. A surrogate measure of lipid content, the C:N ratio, was also compared among 1-sea-winter salmon. The highest levels were associated with the Koksoak River, suggesting that Subarctic populations may require higher energy reserves to contend with their longer migrations and more-severe environmental conditions.

scholarly journals Effects of preservation methods of muscle tissue from upper-trophic level reef fishes on stable isotope values (δ13C and δ15N)

2014 ◽  
Author(s):  
Christopher D. Stallings ◽  
James A. Neslon ◽  
Katherine L. Rozar ◽  
Charles S. Adams ◽  
Kara R. Wall ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Mass Balance ◽  
Muscle Tissue ◽  
Stable Isotope Analysis ◽  
Trophic Level ◽  
Isotopic Ratio ◽  
Isotope Analysis ◽  
Reef Fishes ◽  
Δ13c And Δ15n ◽  
Preservation Methods

Research that uses stable isotope analysis often involves a delay between sample collection in the field and laboratory processing, therefore requiring preservation to prevent or reduce tissue degradation and associated isotopic compositions. Although there is a growing literature describing the effects of various preservation techniques, the results are often contextual, unpredictable and vary among taxa, suggesting the need to treat each species individually. We conducted a controlled experiment to test the effects of four preservation methods of muscle tissue from four species of upper trophic-level reef fish collected from the eastern Gulf of Mexico (Red Grouper Epinephelus morio, Gag Mycteroperca microlepis, Scamp Mycteroperca phenax, and Red Snapper Lutjanus campechanus). We used a paired design to measure the effects on isotopic values for carbon and nitrogen after storage using ice, 95% ethanol, and sodium chloride (table salt), against that in a liquid nitrogen control. Mean offsets for both δ13C and δ15N values from controls were lowest for samples preserved on ice, intermediate for those preserved with salt, and highest with ethanol. Within species, both salt and ethanol significantly enriched the δ15N values in nearly all comparisons. Ethanol also had strong effects on the δ13C values in all three groupers. Conversely, for samples preserved on ice, we did not detect a significant offset in either isotopic ratio for any of the focal species. Previous studies have addressed preservation-induced offsets in isotope values using a mass balance correction that accounts for changes in the isotope value to that in the C/N ratio. We tested the application of standard mass balance corrections for isotope values that were significantly affected by the preservation methods and found generally poor agreement between corrected and control values. The poor performance by the correction may have been due to preferential loss of lighter isotopes and corresponding low levels of mass loss with a substantial change in the isotope value of the sample. Regardless of mechanism, it was evident that accounting for offsets caused by different preservation methods was not possible using the standard correction. Caution is warranted when interpreting the results from specimens stored in either ethanol or salt, especially when using those from multiple preservation techniques. We suggest the use of ice as the preferred preservation technique for muscle tissue when conducting stable isotope analysis as it is widely available, inexpensive, easy to transport and did not impart a significant offset in measured isotopic values. Our results provide additional evidence that preservation effects on stable isotope analysis can be highly contextual, thus requiring their effects to be measured and understood for each species and isotopic ratio of interest before addressing research questions.

Eutrophication processes and trophic interactions in a shallow estuary: Preliminary results based on stable isotope analysis (δ13C and δ15N)

2006 ◽  
Vol 29 (2) ◽  
pp. 277-285 ◽  
Author(s):  
Paulo Cesar Abreu ◽  
César S. B. Costa ◽  
Carlos Bemvenuti ◽  
Clarisse Odebrecht ◽  
Wilhelm Graneli ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Trophic Interactions ◽  
Isotope Analysis ◽  
Δ13c And Δ15n ◽  
Preliminary Results ◽  
Shallow Estuary
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