Response to natural and anthropogenic factors in denitrification and anammox of sediments in the main stream of the Haihe River
In order to reveal the effects of natural environment and human activities on the nitrogen removal process in urban river sediments,the denitrification and anammox reaction rates of sediments in the main stream of Haihe River at 4 ℃ and 25 ℃ were determined by mud experiment combined with 15N isotope tracer technology,respectively.The results showed that:① At 4 ℃ and 25 ℃,the denitrification rates of sediments were 0.11-1.94 mmol N·L-1·h-1 and 0.47-2.73 mmol N·L-1·h-1,respectively.The rate of anammox fluctuated relatively large,with the range of 0.06-1.80 mmol N·L-1·h-1 and 0.28-4.14 mmol N·L-1·h-1,respectively.The rates at high temperature(25℃)were significantly higher than those at low temperature(4 ℃).High tempera-ture(25 ℃)was more conductive to stimulate the enzyme activity of denitrifying and anammox bacteria.② The content of TOC,TN,NH4+,and NO3- in sediment were important physicochemical properties affecting the rate of denitrification and anammox.The content of these parameters in the downstream of the main stream of Haihe River was higher than that in the upstream,and they were all retained in river type reservoirs.Therefore,the denitrification and anammox rates in the downstream were sig-nificantly higher than those in the upstream.③ At 4 ℃ and 25 ℃,the contribution rates of denitrification were 32％and 52％,respectively,and the contribution rates of anammox were 68％and 48％,respectively.The total amount of nitrogen removal that can be removed through denitrification and anammox reactions accounts for about 21.02％and 20.50％of the total nitrogen in the input river,respectively,which can reduce the risk of terrestrial nitrogen export to estuaries and coastal waters.
denitrification rateanammox ratesedimentphysico-chemical propertiesHaihe River
万方数据
维普
