Effects of nutrient enrichment on C and N stable isotope ratios of invertebrates, fish and their food resources in boreal streams
2009 (English)In: Hydrobiologia, ISSN 0018-8158, E-ISSN 1573-5117, Vol. 628, 67-79 p.Article in journal (Refereed) Published
Carbon and nitrogen stable isotopes are frequently used to study energy sources and food web structure in ecosystems, and more recently, to study the effects of anthropogenic stress on aquatic ecosystems. We investigated the effect of nutrient enrichment on d13C and d15N in fine (FPOM), coarse (CPOM) particulate organic matter, periphyton, invertebrates and fish in nine boreal streams in south-central Sweden. In addition, we analysed the diet of benthic consumers using stable isotope data. Increases in d15N of periphyton (R2 = 0.88), CPOM (0.78), invertebrates (0.92) and fish (0.89) were related to nutrient enrichment. In contrast, d13C signatures did not change along the nutrient gradient. Our results show that d15N has potential as a sensitive indicator of nutrient enrichment in boreal streams. Carbon and nitrogen isotopes failed to elucidate putative diets of selected aquatic consumers. Indeed, comparison of low- and high-impact sites showed that d13C of many consumers were found outside the ranges of basal resource d13C. Moreover, ranges of basal resource d13C and d15N overlapped at both low and high sites, making discrimination between the importance of allochthonous and autochthonous production difficult. Our findings show that a fractionation rate of 3.4% is not always be appropriate to assess trophic interactions, suggesting that more studies are needed on fractionation rates along gradients of impairment.
Place, publisher, year, edition, pages
Springer, 2009. Vol. 628, 67-79 p.
Nutrients; FPOM, Periphyton, CPOM, Invertebrates, FIsh, Boreal streams, delta15N, delta13C
IdentifiersURN: urn:nbn:se:liu:diva-65992DOI: 10.1007/s10750-009-9746-4OAI: oai:DiVA.org:liu-65992DiVA: diva2:401008