Fungal contribution to marine nitrogen cycling
We coupled 15N-tracer experiments with a selective inhibition method to determine the contribution of marine fungi to N2O production in the eastern tropical North Pacific oxygen minimum zone. The highest amount of fungal N2O production was measured at the oxic-anoxic interface of the water column, where fungi accounted for ~10% of total N2O production. Metagenomes from the same region harbored the fungal-specific cytochrome P450 nitric oxide reductase (P450nor). We assayed the fungal diversity targeting the internal transcribed spacer region and identified the major members of the fungal community including many novel lineages. Our findings suggest that fungi play an active role in marine nitrogen cycling and highlight the necessity to consider fungi-mediated processes in future studies.