Studies on Nitrogen Fixation by Blue-green Algae I. Nitrogen Fixation by Anabaena Cylindrica Lemm

RECENT work, particularly that of De (1939), has shown that some blue-green algae are capable of utilizing the free nitrogen of the atmosphere in the synthesis of cell material. Much further work will be necessary, however, before the importance of nitrogen fixation by these organisms in nature can be estimated, our knowledge both of the distribution of the property within the group of the Myxophyceae and of the physiology of the process being very vague. The aim of the present paper is to present proof of nitrogen fixation by a species of Anabaena which has not hitherto been examined from this point of view. Later it is hoped to publish the results of investigations on some physiological aspects of the fixation process in the same species.