Chapter 4 - Dynamics of Dissolved Organic Nitrogen

Abstract

Dissolved organic nitrogen (DON) is that subset of the dissolved organic carbon (DOC) pool that also contains N. This chapter reviews four major areas of DON research. First, DON concentrations and distributions in aquatic environments are reviewed with respect to the methods used to analyze DON concentrations, global distributions, comparison of DON concentration across a range of aquatic systems and seasonal variations. Second, the composition of the characterizable and uncharacterized DON is reviewed with respect to pools of specific DON forms and the methods used to study and chemical characteristics of the fraction of the DON pool that is not defined. Third, sources of DON to the water column are reviewed with respect to autochthonous sources, allochthonous sources, methods used to measure rates of DON release and release rates of bulk DON and individual DON forms in the literature. The final section reviews sinks for DON with respect to DON bioavailability, methods used to estimate DON uptake rates, mechanisms that contribute to DON bioavailability, and DON uptake rates published in the literature. Recommendations for future research are presented for each research area. This chapter focuses on work published largely after 2001 and topics not included in the earlier review (Bronk, D.A., 2002. Dynamics of DON. In: Hansell, D.A., Carlson, C.A. (eds.) Biogeochemistry of Marine Dissolved Organic Matter. Academic Press, San Diego).