I think you are referring to Anammox bacteria (not Annamox).
I think these authors studied the Anammox in marine systems:
Rysgaard, S., Glud, R. N., Risgaard-Petersen, N. and Dalsgaard, T. (2004). Denitrification and anammox activity in Arctic marine sediments. Limnology and Oceanography 49(5): 1493-1502
Tage Dalsgaard, Bo Thamdrup, Laura Farías, Niels Peter Revsbech
Anammox and denitrification in the oxygen minimum zone of the eastern South Pacific