Nitrous oxide production by estuarine epiphyton

Nitrous oxide was produced by denitrifying bacteria in epiphytic communities on the surface of the macroalgae Enteromorpha sp. and Fucus sp. during spring-summer in the Tamar estuary, SW England. Denitrification and N2O production exhibited diel variability, in response to photosynthetic oxygen production. Temporal variability in the rate of N2O production was observed in Enteromorpha incubations; the variability reflected the heterogeneity of the epiphytic microbial population density. N2O production by epiphyton associated with Enteromorpha would enhance the sediment N2O flux by 150–500% at maximal algal densities and so increase estuarine N2O flux to the atmosphere.