Stable carbon isotope ratios differentiate autotrophs supporting animal diversity in Lake Baikal

Resource partitioning in endemic species of Baikal gastropods indicated by gut contents, stable isotopes and radular morphology

“…Reproducibility of repeated analyses of gastropod tissues was better than ±0.1%. For comparative context, we used data of Kiyashko et al (1998) and Yoshii (1999) on carbon and nitrogen isotopes in the Lake Baikal littoral.…”

“…3 Plot of the d 13 C and the d 15 N values (means and SD) of sympatric Baikal gastropods in an underwater canyon. Isotopic data on plankton diatoms and benthic algae are presented after Kiyashko et al (1998), Yoshii (1999), Yoshii et al (1999). Trophic levels are shown according to Yoshii et al (1999) components of the gut are likely to track the variation in available food resources, though notably there are differences among sympatric species.…”

“…3, we compare the isotope composition of our focal gastropod species and the principal sources of organic matter in the littoral zone of Lake Baikal using published data (Kiyashko et al, 1998;Yoshii et al, 1999). Baikal phytoplankton, which is dominated by diatoms, is characterized by relatively constant isotopic composition with mean d 13 C and d 15 N values of -28.0 and 4.2%, respectively (Kiyashko et al, 1998;Yoshii et al, 1999). Benthic macro-and microalgae, including periphytic diatoms, are characterized by much higher d 13 C values, from -14.0 to -5.0% (Kiyashko et al, 1998), although their average d 15 N 3.0 % is similar to phytoplankton (Yoshii, 1999).…”

“…Baikal phytoplankton, which is dominated by diatoms, is characterized by relatively constant isotopic composition with mean d 13 C and d 15 N values of -28.0 and 4.2%, respectively (Kiyashko et al, 1998;Yoshii et al, 1999). Benthic macro-and microalgae, including periphytic diatoms, are characterized by much higher d 13 C values, from -14.0 to -5.0% (Kiyashko et al, 1998), although their average d 15 N 3.0 % is similar to phytoplankton (Yoshii, 1999). Phytoplankton seems to be the primary carbon source for the four focal species of baicaliids, as indicated by the similarity in d 13 C values (Fig.…”

“…B Habitat of the snails-canyon wall at 15 m in Lake Baikal (photo by O. Timoshkin) isotopic labels to indicate the source of consumed foodstuffs and position in the food web. In Lake Baikal, phytoplankton and primary benthic producers differ markedly by the content of 13 C isotope (Kiyashko et al, 1991(Kiyashko et al, , 1998Yoshii et al, 1999), which enables identification of principal food sources for littoral animals. Regular enrichment of consumers by heavy isotopes along the food chain in Baikal ecosystem is reported to be 1.2 and 3.3% at each trophic level, for carbon and nitrogen, respectively .…”