Figure 4
The δ13C values extracted from subfossil Daphnia ephippia, chironomid headshields and bulk sediment samples from Kings Billabong. A marked shift in carbon source is revealed over time in all three proxies. From 1910 to 1930, the source of carbon was relatively high (δ13C > − 23‰). From 1930 to 1970 and 1980 the carbon source continued to decline, and was variable among the proxies; and after 1980 the carbon source further depleted in all proxies. The depleted δ13C values also corresponded to the change in the dynamics of subfossil littoral cladoceran (e.g. D. crassa) assemblage as shown in Fig. 3 reflecting the possible reduction in the sub-merged macrophyte-derived carbon source for primary and secondary consumers.
