Low Concentrations of Deuterium Oxide and the Growth of Marine Diatoms

Abstract

An early suggestion was made by Barnes and Jahn' that if slight increases in the concentration of the heavy isotope of water should occur through fractionation during the slow sublimation of ice and snow masses, the extra traces of D 2 0 might help to explain the increased reproductive activity of organisms in waters from frozen sources during the spring of the year. I n view of this interesting suggestion, and because of the very contradictory reports regarding stimulative, retarding or inhibitory effects, or complete lack of influence of heavy water solutions upon growing organisms or enzyme systems (cf. Fox'), it seemed of interest to investigate carefully the relative growth rates of some isolated cultures of marine diatoms in nutrient sea water alone and in the same medium to which had been added small amounts of (1) ordinary twice-distilled water, and (2) highly pure D'O.Fresh sea water, collected from the ocean in glass vessels, was passed through a Berkefeld filter candle of fine porosity; modified * P represents a preliminary, C a complete manuscript.

Influence of Heavy Water on Growth, Morphology, and Fermentation Reactions of Eberthella typhosa

“…The osmotic effects of heavy water on the leaf cells of Nitella clavata was studied by Brooks (1937), who found that the cells shrank in heavy water and expanded in normalwater. It was concluded that heavy water was hypertonic to the cells.Fox, Cupp, and McEwen (1936) measured the growth of diatoms in 1 per cent heavy water and in filtered sea water. They reported a lag of 16 per cent in the growth rate of Nilzschia bilabata over a period of 12 days in heavy water.…”

“…It was concluded that heavy water was hypertonic to the cells. Fox, Cupp, and McEwen (1936) measured the growth of diatoms in 1 per cent heavy water and in filtered sea water. They reported a lag of 16 per cent in the growth rate of Nilzschia bilabata over a period of 12 days in heavy water.…”