Carbon Sources Supporting Large River Food Webs: A Review of Ecological Theories and Evidence from Stable Isotopes

Abstract

Abstract Quantifying the contributions of carbon sources that support food webs in large rivers is an important and growing field of ecological research with implications for future management and rehabilitation. Here we review theoretical concepts and recent empirical evidence that address carbon flow through aquatic food webs in large rivers. The literature reviewed focuses on studies using stable isotope analysis, which is a tested framework for identifying the origin of carbon sources that are assimilated by primary consumers and subsequently transferred through the food web to support higher consumers. Theoretical concepts addressing carbon flow in large river food webs have tended to stress the importance of organic matter originating from different sources, such as floodplains (Flood Pulse Concept), local riparian and aquatic primary producers (Riverine Productivity Model), or leakage from upstream processing of terrestrial organic matter (River Continuum Concept). Recent empirical evidence from a ...