두 삼림호수에 공존하는 동물플랑크톤종의 다른 안정동위원소비

초록

The stable isotopes ratios (δ13C and δ15N) of two coexisting species of zooplankton (Daphnia longispina and Acanthodiaptomus pacificus) and POM were determined in two alpine lakes in Japan. The difference of δ13C between A. pacificus and D. longispina was 4.1±0.9‰ in Lake Shirakoma, which was larger than in Lake Panke. Whereas the difference of δ15N between A. pacificus and D. longispina (2.6±0.8‰) was larger in Lake Panke than in Lake Shirakoma. δ13C of POM (-26.6±1.2‰) in Lake Shirakoma was different from those of zooplankton; it was heavier than those of D. longispina and A. pacificus by 3.7±1.6‰ and 7.8±1.0‰, respectively. Whereas δ15N of POM (2.0±0.8‰) was similar with those of both A. pacificus and D. longispina. This implies that the two lakes may have different trophic structure and food sources for zooplankton, and each species are grazing on selectively different components of POM. The temporal variation of δ13C for each zooplankton species was associated with lipid contents of zooplankton in both lakes. The results showed that stable isotope composition of zooplankton can be an useful information for understanding energy pathways and trophic structures in lakes.

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