Alteration of Dissimilatory Nitrate Reduction Pathways in the Intertidal Sediment during Macroalgae Blooms

To elucidate the effect of macroalgae blooms on dissimilatory nitrate reduction pathways (denitrification, anammox, and DNRA) in sediments hypereutrophic Yatsu tidal flat, eastern Japan, sediment denitrification, DNRA rates were measured using a 15N tracer technique at two sites affected unaffected by (Ulva) incubation experiments with without Ulva. Anammox was insignificant both experiments. The denitrification rate consistently higher than rate, its contributions to total 82% 85% Ulva, respectively. In experiment contribution had increased approximately 30% day 7, which is when sulfide concentration highest. Sulfide produced sulfate during inhibited did not change DNRA, consequently contribution. On 21, after reaching peak late collapse, decreased 15%. These results indicated that greater although dominated regardless macroalgal status. Therefore, vigorous cover production under an important impact nitrogen dynamics.