Natural nutrient cycling in aquatic ecosystem N,atmosphere) (soll; detergents; sewage nitrates(soil; sewage) COz(atmosphere) (usually limited) (possibly limited (usually plentiful) (Sufficient O2) Trace elements CO 〔Fe,Mn,Cu,etc.) Primary Prod FEE algae and other nitrogen fixing and photosynthetic organisms assimilate Bacterial Decomposition C N, Pin the atomic ratios of 106: 16: 1 of plant and animal debris Growth of fish ad ouer secondary producers (Sufficient O,) ag吗g Sedimentation of plant and animal debrisNatural nutrient cycling in aquatic ecosystem