RELATIONSHIPS BETWEEN DENITRIFICATION ACTIVITY AND ENVIRONMENTAL FACTORS IN THE TIDAL SEDIMENT OF THE INNER AREA OF THE ARIAKE BAY

摘要

The relationships between denitrification activity and environmental factors in the tidal sediments of the inner area of the Ariake Bay were investigated based on in situ and laboratory data. Statistically significant differences were found between the mean values of the number of denitrifiers in the muddy sediments, and in the mud-sandy sediments and in the sandy sediments (t test, P<0.05). In the muddy sediments, a significant correlation was found between denitrification rate in the sediment and NO_3~-+NO_2~- -N flux from the overlying sea water into the tidal sediment (r~2=0.25, P<0.01). This study concluded that 47 % of NO3~+NO_2~--N intake from the overlying water into the tidal sediment was consumed by denitrification, and that the remainder was used as a substrate for assimilation of NO_3~- reduction. The denitrification activity in the muddy sediments was influenced strongly by C/N ratio and NO_3~-+NO_2~--N in the sea water.