Transfer of Biologically Fixed Nitrogen in a Sand Dune Slack Region

Abstract

IT has previously been reported¹ that natural populations of blue-green algae occurring in an area of sand dune slack at Blakeney Point, Norfolk, assimilate appreciable quantities of elemental nitrogen from the atmosphere during spring, summer and autumn, when there is often an abundant growth of gelatinous Myxophyceae. Although the algae partially disappear during the summer months they remain in certain restricted areas, particularly in the damper areas and among long grass where the algal thalli are protected from desiccation and high light intensities. The highest rates of nitrogen fixation so far recorded at Blakeney Point have been obtained in the latter ecological niche. The data presented in Table 1 emphasize the contrast in fixation recorded in open, drier areas and in damper areas shaded by long grass, while the results in Table 2 indicate that the summer decrease in the more open areas is due in part at least to desiccation.