C diagram for the ecosystem in Lake Biwa. Both pelagic and littoral food chains are shown. The estimated isotopic range of Lake Biwa before substantial eutrophication (ca. 1960s to 1980s) is shown as the area surrounded by a broken line. POM, particulate organic matter. Colors indicate the food web groups estimated by Yamada et al. (1998): green, primary producers; black, primary consumers; red, secondary consumers; blue, tertiary consumers. Modified from Yamada et al. (1998) and Wada (2009).