School of Natural and Environmental Sciences


Is denitrification a nitrous oxide sink?

The broad aim is to interrogate recent findings that imply high nitrous oxide (N2O) production in sub-oxic environments to be principally associated with the activity of nitrifying bacteria, rather than respiratory denitrification as is traditionally assumed. The notion of microbial denitrification in marine sediments as a net source of N2O to overlying water and air deserves further examination and this is prompted by recent evidence that indicates that sediment denitrification could indeed be a net N2O sink. Controlled laboratory experiments designed to examine the relative contributions of nitrification and denitrification to N2O production and sediment-water exchange in sediments from the Tyne estuary and the adjacent coastal and offshore North Sea will examine the roles of O2 content and redox status, dissolved N supply (concentration, oxidation state) and temperature in controlling sediment N2O production and consumption.