A Freshwater Lake Saga: Carbon Routing Within the Aquatic Food Web of Lake Schwerin

Abstract

Recently, several case studies have demonstrated the presence of human radiocarbon dietary reservoir effects in inland contexts. Freshwater reservoir effects present a high degree of variability, making it difficult to define local reservoir effect reference values necessary for correcting chronologies based on 14C dating of human bone material. Here, we investigate the hypothesis that 14C ages of edible freshwater species are delimited by the 14C ages of the main water carbon pools (DIC, POC, and DOC).Water, plant, algae, bivalve, and fish samples were collected from lakes Schwerin and Ostorf (Germany). 14C and isotopic measurements were performed on the floral and faunal species and on water DIC, POC, and DOC. The results demonstrate the potential of the study area for large and variable freshwater reservoir effects. In the case of Lake Schwerin, the working hypothesis was verified as the 14C ages of faunal and floral species were delimited by the 14C ages of water DIC and POC, probably associated with 2 extreme categories of food chains (grazing and detritus). While the results obtained confirm the working hypothesis and suggest a relatively straightforward interpretation, further research is necessary to investigate possible spatial and seasonal variations.