Author(s): Giyoung Ock; Yasuhiro Takemon
Linked Author(s):
Keywords: SPOM dynamics; Dam impact; Stable isotope mixing model; Riffle-poolstructure; Limnoperna fortunei
Abstract: Downstream changes in source composition of suspended particulate organic matter (SPOM) in dam tailwaters were investigated quantitatively at each subsequent riffle-pool structure the Uji River of Japan. Results showed that SPOM consisted of lentic plankton produced in the reservoir, terrestrial plant and instream attached algae. Stable isotope mixing model using δ`15N and δ`13C resulted in comparatively large contribution of lentic plankton ranging 0.51-0.88 showing steep reduction during drift in riffles. The population density and biomass of freshwater golden mussel, Limnoperna fortunei, also showed a similar decreasing pattern in riffles. These findings suggest that lentic plankton is dominant source of SPOM in dam tailwaters and its source composition can be changed even within a short distance of a hundred meter scale being strongly influenced by riffle-pool geomorphological structure. Interrelationship between SPOM source composition and density of filter-feeding mussels was also discussed.
Year: 2009