Nitrogen-Cycling Functional Genes in Brackish and Freshwater Sediments in Yodo River in Japan

Abstract

A DNA microarray analysis targeting nitrogen-cycling functional genes was applied to monitor sediment microbes in the Juso Lagoon (brackish area) and the Shirokita Wando (freshwater area) along the Yodo River in Japan in 2014–2015. The microarray contained 905 oligonucleotide probes for the nif, amo, hao/hzo, nap, nar, nirK, nirS, nrf, cnor, qnor, and nos genes. Diverse genes were detected in the sediment samples. Especially in the summer brackish area, about 70 probes were detected, 26–31, 11–12, and 31–32 of which targeted genes on nitrogen-fixation, nitrification, and denitrification, respectively. Canonical correspondence analysis showed that the nitrogen-cycling functional gene profiles of the sediment microbes were characterized by nitrification activity, denitrification activity, conductivity, pH, temperature, and vegetation of their habitats.