Organic geochemical perspectives on estuarine processes: sorption reactions and consequences

The conventional paradigm for conceptualizing the behavior of bioactive materials in estuarine systems has been to think of dissolved and particulate organic matter as separate entities that do not readily interconvert or associate with minerals. However, many organic molecules are extensively, and to some extent reversibly, associated with mineral surfaces in rivers and estuaries. The realization that some organic molecules may actively partition between dissolved form and the surfaces of minerals has great geochemical implications for many natural environments. This brief review touches on some possible ramifications of organic–mineral interactions for estuaries, using the well-studied Amazon River/Estuary system as an example.