scholarly journals Intra-specific differences in metabolic rates shape carbon stable isotope trophic discrimination factors of muscle tissue in the common teleost Eurasian perch (Perca fluviatilis)

2021 ◽  
Author(s):  
Kristin Scharnweber ◽  
Matilda Andersson ◽  
Fernando Chaguaceda ◽  
Peter Eklöv
Keyword(s):  
Stable Isotopes ◽  
Stable Isotope ◽  
Muscle Tissue ◽  
Liver Tissue ◽  
Perca Fluviatilis ◽  
Δ13c And Δ15n ◽  
Perch Perca Fluviatilis ◽  
Discrimination Factors ◽  
Relationship Of ◽  
Trophic Discrimination

1. Stable isotopes represent a unique approach to provide insights into the ecology of organisms. δ13C and δ15N have specifically be used to obtain information on the trophic ecology and food web interactions. Trophic discrimination factors (TDF, Δ13C and Δ15N) describe the isotopic fractionation occurring from diet to consumer tissue and these factors are critical for obtaining precise estimates within any application of δ13C and δ15N values. It is widely acknowledged that metabolism influences TDF, being responsible for different TDF between tissues of variable metabolic activity (e.g. liver vs. muscle tissue) or species body size (small vs. large). However, the connection between the variation of metabolism occurring within a single species during its ontogeny and TDF has rarely been considered. 2. Here, we conducted a 9-month feeding experiment to report Δ13C and Δ15N of muscle and liver tissue for several weight classes of Eurasian perch (Perca fluviatilis), a widespread teleost often studied using stable isotopes, but without established TDF for feeding on a natural diet. In addition, we assessed the relationship between the standard metabolic rate (SMR) and TDF by measuring their oxygen consumption of the individuals. 3. Our results showed a significant negative relationship of SMR with Δ13C, and a significant positive relationship of SMR with Δ15N of muscle tissue, but not with TDF of liver tissue. SMR varies inversely with size, which translated into a significantly different TDF of muscle tissue between size classes. 4. In summary, our results emphasize the role of metabolism in shaping specific TDF (i.e. Δ13C and Δ15N of muscle tissue), and especially highlight the substantial differences between individuals of different ontogenetic stages within a species. Our findings thus have direct implications for the use of stable isotope data and the applications of stable isotopes in food web studies.

scholarly journals Intra-specific differences in metabolic rates shape carbon stable isotope trophic discrimination factors of muscle tissue in the common teleost Eurasian perch (Perca fluviatilis)

2021 ◽  
Author(s):  
Kristin Scharnweber ◽  
Matilda Andersson ◽  
Fernando Chaguaceda ◽  
Peter Eklöv
Keyword(s):  
Stable Isotopes ◽  
Stable Isotope ◽  
Food Web ◽  
Muscle Tissue ◽  
Liver Tissue ◽  
Perca Fluviatilis ◽  
Eurasian Perch ◽  
Δ13c And Δ15n ◽  
Perch Perca Fluviatilis ◽  
Trophic Discrimination

1. Stable isotopes represent a unique approach to provide insights into the ecology of organisms. δ13C and δ15N have specifically be used to obtain information on the trophic ecology and food web interactions. The trophic discrimination factor (TDF, Δ13C and Δ15N) describes the isotopic fractionation occurring from diet to consumer tissue and this value is critical to obtain precise estimates within any application of δ13C and δ15N. It is widely acknowledged that metabolism influences the TDF, being responsible for different TDFs between tissues of variable metabolic activity (e.g. liver vs. muscle tissue) or species body size (small vs. large). However, the connection between the variation of metabolism occurring within a single species during its ontogeny and TDFs has rarely been considered. 2. Here, we conducted a 9-month feeding experiment to report Δ13C and Δ15N of muscle and liver tissue for several weight classes of Eurasian perch (Perca fluviatilis), a widespread teleost often studied using stable isotopes, but without established TDFs for feeding on a natural diet. In addition, we assessed the relationship between the standard metabolic rate (SMR) and TDFs by measuring their oxygen consumption of the individuals. 3. Our results showed a significant negative relationship of SMR with Δ13C, but not with Δ15N of muscle or TDFs of liver tissue. SMR was significantly higher in perch juveniles, which translated to significantly lower Δ13C of muscle tissue. 4. In summary, our results emphasize the role of metabolism in shaping specific TDFs (i.e. Δ13C of muscle tissue), and especially highlight the substantial differences between individuals of different ontogenetic stages within a species. Our findings thus have direct implications for the use of stable isotope data and the applications of stable isotopes in food web studies.

Matching and mismatching stable isotope (δ13C and δ15N) ratios in fin and muscle tissue among fish species: a critical review

2013 ◽  
Vol 160 (7) ◽  
pp. 1633-1644 ◽  
Author(s):  
Trevor J. Willis ◽  
Christopher J. Sweeting ◽  
Sarah J. Bury ◽  
Sean J. Handley ◽  
Julie C. S. Brown ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Muscle Tissue ◽  
Fish Species ◽  
Critical Review ◽  
Δ13c And Δ15n

Variation in δ13C and δ15N diet–vibrissae trophic discrimination factors in a wild population of California sea otters

2010 ◽  
Vol 20 (6) ◽  
pp. 1744-1752 ◽  
Author(s):  
Seth D. Newsome ◽  
Gena B. Bentall ◽  
M. Tim Tinker ◽  
Olav T. Oftedal ◽  
Katherine Ralls ◽  
...  
Keyword(s):  
Wild Population ◽  
Sea Otters ◽  
Δ13c And Δ15n ◽  
Discrimination Factors ◽  
Trophic Discrimination

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.

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