BACTERIA AND THE PHOSPHORUS CYCLE IN THE SEA'

Marine bacteria, growing and multiplying rapidly under favorable conditions, are potential accumulators of the sea's labile organic matter. Lohmann (1911) has estimated that they may bind as cell substance each year from six to three hundred times the annual production of slower growing nannoplankton feeding upon them. It is surprising, then, to discover, as Fischer (1894) and many others since have pointed out, that the bacterial population of the sea and large fresh-water lakes is very low—rarely exceeding a viable count of a hun dred at the surface and extending through a lesser range in the depths (Birge and Juday, 1922; Reuszer, 1933). Lohmann found the mass of bacterial cells in sea water to represent an insignificant fraction of the nannoplankton; and it may be calculated, making generous allowance for non-viable cells, that the amount of phosphate, nitrate, or other nutrient substance bound by bacteria is immeasurably small. Thus, a million cells per cubic centimeter, at least a thousand times the likel