EVLUETION OF DIETARY UTILIZATION OF BLOOM-FORMING CYANOBACTERIA BY SMALL-BODIED CRUSTACEAN ZOOPLANKTON USING FATTY ACID ANALYSIS

Abstract

 Cyanobacteria have been considered difficult to use as dietary sources by consumers; however, it is unknown whether consumers in eutrophic lakes utilize cyanobacteria. Therefore, fatty acid analysis was used to examine the utilization of cyanobacteria by Bosmina longirostris, Diaphanosoma brachyrum, and adult Copepoda in Lake Hachiro (Akita Prefecture, Japan), which is a eutrophic lake where algal blooms occur every year. The levels of cyanobacterial markers (18:2ω6 and 18:3ω3) in each of the crustacean species increased during the summer bloom period, indicating that the zooplanktons assimilated cyanobacteria. In particular, B. longirostris, the dominant zooplankton species in Lake Hachiro, had the highest cyanobacteria-derived fatty acid content among the analyzed zooplanktons. Our findings indicated that B. longirostris plays an important role in cyanobacteria-derived nutrient transfer to higher trophic consumers in lake food webs.