Variation in trophic shift for stable isotope ratios of carbon, nitrogen, and sulfur

Abstract

2003. Variation in trophic shift for stable isotope ratios of carbon, nitrogen, and sulfur. -Oikos 102: 378-390.Use of stable isotope ratios to trace pathways of organic matter among consumers requires knowledge of the isotopic shift between diet and consumer. Variation in trophic shift among consumers can be substantial. For data from the published literature and supplementary original data (excluding fluid-feeding consumers), the mean isotopic shift for C was + 0.5 9 0.13‰ rather than 0.0‰, as commonly assumed. The shift for C was higher for consumers analyzed as muscle ( + 1.3 9 0.30‰) than for consumers analyzed whole ( + 0.3 9 0.14‰). Among consumers analyzed whole, the trophic shift for C was lower for consumers acidified prior to analysis ( −0.2 90.21‰) than for unacidified samples ( + 0.59 0.17‰). For N, trophic shift was lower for consumers raised on invertebrate diets ( + 1.4 90.21‰) than for consumers raised on other high-protein diets ( + 3.39 0.26‰) and was intermediate for consumers raised on plant and algal diets ( + 2.29 0.30‰). The trophic shift for S differed between high-protein ( +2.0 9 0.65‰) and low-protein diets (-0.5 90.56‰). Thus, methods of analysis and dietary differences can affect trophic shift for consumers; the utility of stable isotope methods can be improved if this information is incorporated into studies of trophic relationships. Although few studies of stable isotope ratios have considered variation in the trophic shift, such variation is important because small errors in estimates of trophic shift can result in large errors in estimates of the contribution of sources to consumers or in estimates of trophic position.

Influence of dietary composition on the carbon, nitrogen, oxygen and hydrogen stable isotope ratios of milk

“…First, differences in the content of fibre, cellulose, 38 lignin, starch, etc., in C 3 and C 4 plants might lead to different digestibility and therefore preferential assimilation of a certain nutrient by the animals. 4 Secondly, in the case of thesis 0, there might be an effect of the previous diet (thesis 1) because, in contrast to the findings of Wilson et al, 24 2 weeks are not long enough to obtain a complete turnover of carbon in casein. This is probably because the body proteins, which could contribute to up to 30% of casein production, need Table 3.…”

“…with a lower C/N ratio) lead to a lower d 15 N enrichment. 4 Thus, the main reason for this shift could be the different assimilation rate of the dietary ingredients according to their different digestibility (Festuca and cotton were probably preferred to the other components).…”

“…The aims of these studies were to obtain dietary reconstruction, to study animal movement patterns, [1][2][3][4][5] and to characterise the geographical origin. [6][7][8][9][10][11][12][13][14][15][16] Another important aim could be to study and quantify the alteration of stable isotope ratios (SIRs) in milk by substituting a C 3 plant diet with maize.…”

Applications of C and N stable isotopes to ecological and environmental studies in seagrass ecosystems

“…Hobson and Welsh, 1992) but this 15 N enrichment is variable; it varies between animal groups and is often diet-related (e.g. Mac Cutchan et al, 2003;Vanderklift and Ponsard, 2003). Stable isotopes (C, N, S) have been largely used to assess seagrass food webs in temperate meadows (e.g.…”

Organochlorine Pollutants and Stable Isotopes in Resident and Migrant Passerine Birds from Northwest Michoacán, Mexico

“…On average and assuming a d 15 N progressive enrichment of 3.0 % with each trophic transfer (McCutchan et al 2003), the dusky flycatchers and some least flycatchers fed two to three trophic levels above the warbler species, particularly the yellow-rumped warbler at their respective regions of feather growth. Differences in diet between warbler and flycatcher species have been reported (Yard et al 2004).…”