典型河口区硝态氮短程还原成铵的活性氮累积途径研究进展

Active nitrogen accumulation mechanism in typical estuarine regions based on dissimilatory nitrate reduction to ammonium

为了揭示水体特有的,具生物活性的氮素积累而造成水生态恶化的内因,对河口区氮循环的非传统生物转化途径,即硝态氮异化还原成铵(DNRA)的活性氮累积途径进行综合分析。河口环境特征与相应的微生物生态学研究表明:相对高温高盐的滨岸带系统里夏季富营养化严重,生物活性氮素通量高;在浅水河口的DNRA是氮转化客观存在的"链节"(相应地成为反硝化的汇)。高盐环境下的沉积物有充足的碳源,具备DNRA菌糖代谢发酵的条件,从而可能具备与反硝化过程竞争的环境条件。认为应结合河口特征如气候、盐度、微生物种类等对DNRA的关联机制展开深入细致的研究,为我国河口地区的氮素总量控制管理及富营养化水平评价提供生物学基础。

In order to explore the internal causes of aquatic ecological deterioration by biological active nitrogen accumulation , which specifically occurs in water bodies , we comprehensively analyze the non-traditional biological conversion paths of nitrogen cycling , i.e., the paths of active nitrogen accumulation based on dissimilatory nitrate reduction to ammonium （ DNRA ） , in estuarine regions .Studies of estuarine environmental characteristics and microbial ecology show that there exist severe eutrophication and large fluxes of biological active nitrogen in the summer in the riparian zone , with relatively high temperature and salinity .DNRA in a shallow estuary is the chain unit for the occurrence of nitrogen conversion .The sediments in a high-salinity environment have sufficient carbon sources and can meet the requirements of DNRA carbohydrate metabolism fermentation .Thus, they may satisfy the conditions for competing with the denitrification process .We suggest that future studies should be focused on relationships between estuarine climate , salinity, microbe species, and DNRA.This study provides a biological basis for total nitrogen control and eutrophic status evaluation in estuarine regions of China .