Dynamics of dissolved organic carbon in a stream during a quarter century of forest succession
Dissolved organic carbon (DOC) is a heterogeneous mixture of compounds that makes up a large fraction of the organic matter transported in streams. It plays a significant role in many ecosystems. Riverine DOC links organic carbon cycles of continental and oceanic ecosystems. It is a significant trophic resource in stream food webs. DOC imparts color to lakes, regulating the amount of ultraviolet radiation reaching lake biota and influencing lake thermal regimes. Cycling and biotic impact of metals are influenced by DOC concentration; for example, the concentration of methyl mercury in lakes and in lake biota increases with their DOC content. A synthesis of lake research identified colored DOC as a key characteristic of lakes, determining a lake’s response to multiple anthropogenic stressors. Because DOC regulates so many aspects of aquatic ecosystems, it is important to understand how natural and anthropogenic changes can alter its concentration in lotic ecosystems.