DECOMPOSITION AND REGENERATION OF NITRO GENOUS ORGANIC MATTER IN SEA WATER IV. INTERRELATIONSHIP OF VARIOUS STAGES; INFLUENCE OF CONCENTRATION AND NATURE OF PARTICULATE MATTER 1

strated that the decomposition of particulate organic matter in sea water proceeds in well-defined steps, the main stages being the formation of. ammonia, nitrite and nitrate. The appearance of these substances is due to the successive development of different bacterial floras acting upon the original substratum of organic matter. In nature, however, a mix ture of the various floras will probably occur, with frequent or continu ous addition of new decomposing material. It seenied desirable, there fore, to study the interrelationship of the different Stages of the cycle and the results obtained when two or more stages occur simultaneously. For this purpose a 20-liter carboy of filtered sea water from Woods Hole Harbor, to which washed diatoms (Nitzschia Closteriurn) were added, was kept at room temperature in the dark. In order to deter mine what effect the bacterial flora present at various stages would have on the decomposition of fresh organic matter, portions of the culture were withdrawn at various times during the decomposition cycle. Ne