Nitrogen fixation activities in the sediment of the mangrove swamp at Gazi Bay, Kenya

Abstract

Nitrogen fixation activity in the sediments of the mangrove swamp at Gazi bay was estimated using the acetylene-reduction method. The highest rates of acetylene-reduction were observed in the Rhi=ophora mucronata plot (0-51.5 nmol C2H4 /g dry wt./h) while the lowest rates were recorded in the Ceriops taga! Plot (0.01-1.29 nmol of C2HJg dry wt./h). The rates of acetylene reduction in the Avicennia marina plot were 0.41-15.17 nmol of C2HJg dry wt./h. It was apparent that the organic matter content of sediments in the respective plots had an influence on the acetylene reduction rates, because the highest rates of acetylene reduction were recorded in the plot with the highest organic matter content, and the lowest rates were recorded in the plot with lowest organic matter content.