“…In areas of high OM deposition, such as beneath oyster cages, hydrogen sulfide (H 2 S) can build up, subsequently inhibiting rates of nitrification and denitrification (21,22). In addition to these 4 elements (C, N, P and S), oyster mediated OM loading can also enhance the availability of heavy (such as Cu, Zn, and Pb: 23-25) and trace metals (such as As, Cd, Co, Cr, Fe, Mn, and Ni: 26,27), several of which are required in enzymes that perform microbial metabolism. For example, enzymes important for denitrification such as nitrate reductase, requires a molybdenum (Mo) protein cofactor for reducing nitrate to nitrite (28) and nitrous oxide reductase requires copper (Cu) for reducing nitrous oxide (N 2 O) to di-nitrogen (N 2 ) (29).…”