Dissolved Organic Carbon

Abstract The importance of dissolved organic carbon (DOC) lies in its role in the biogeochemical carbon cycle, as a necessary basis for aquatic microbial processes and in aquatic chemistry. Although the global burden of carbon is dominated by sediments, dissolved organic carbon is of obvious importance as carbon is the basis of life, an energy and nutrient source for microorganisms. DOC is also of significance in trace pollutant binding (and consequently in pollutant transport and bioavailability), in the charge and aggregation behavior of colloids, in weathering, in pH buffering, and in acid–base and redox chemistry of natural waters. It thus has a large and essential role in determining the chemical composition of natural waters. Although microbiological and chemical aspects are frequently taught and researched in isolation, it may be impossible to understand the composition and regulation of natural waters without simultaneously considering the microbiological and chemical processes because they are so closely interlinked. Any distinction between the two processes is therefore likely to be arbitrary and misleading.