Chapter 15 - Modeling DOM Biogeochemistry

Abstract

Numerous significant developments have taken place in the development of models of DOM dynamics over the last 10 years. Diversity in approach is unsurprising given the complexity of DOM cycling in the ocean including multiple source terms, variable lability and stoichiometry and a mixed bacterial community. Despite this proliferation of approaches, key common concepts still prevail, notably the division of DOM into labile, semi-labile and refractory pools. Mechanistic approaches often remain tentative and speculative and, as a result, global biogeochemical modeling studies often default to using simple parameterizations. The current generation of global biogeochemical models do not, however, agree even on the general spatial and seasonal pattern of DOM distribution. Future developments in modeling DOM biogeochemistry should in particular consider critical issues such as just what constitutes DOM, as well as factors that determine lability (both of which require matching with empirical methodology for their robust measurement in the field) in order that DOM can be compartmentalized into meaningful state variables, with realistic descriptions of source and sink terms.