Dualism of denitrification and dissimilatory nitrate reduction to ammonium in sediment of nitrate-polluted aquatic ecosystems

硝酸盐污染水生生态系统沉积物中反硝化与异化硝酸盐还原成铵的二元性

• 批准号: 81713479
• 负责人: Dr. Peter Stief
• 金额: --
• 依托单位: Institut für Biologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2008
• 资助国家: 德国
• 起止时间: 2007-12-31 至 2011-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/81713479?language=en
• 关键词: Dualism; denitrification; dissimilatory; nitrate; reduction

Dissimilatory nitrate reduction by sediment bacteria is the quantitatively most important sink for nitrate that promotes the eutrophication of aquatic ecosystems. Incomprehensibly, in most cases only denitrification (DEN) that converts nitrate into nitrogen gas has been subject of research. In this study, however, the dissimilatory nitrate reduction to ammonium (DNRA), which maybe is quantitatively important in many aquatic ecosystems, will be investigated. DNRA is not effective against eutrophication because the ammonium produced is preserved in the ecosystem. The central goal of this study is the comparative and equitable investigation of DNRA and DEN in order to better understand the controlling abiotic factors (e.g., nitrate, sulfide, organic carbon, iron). In a novel approach, the vertical distribution of both DNRA and DEN in the sediment will be analysed with microsensors, gel probes, and mass spectrometry. Abundance and activity of the nitrate-reducing microbial community will be studied on the level of functional genes (here: nitrite reductases) with molecular techniques. Results obtained in laboratory experiments using benthic gradient chambers, natural sediments, and bacterial isolates will be validated at relevant field sites.

底泥细菌异化还原硝酸盐是促进水生生态系统富营养化的最重要的硝酸盐汇。令人费解的是，在大多数情况下，只有将硝酸盐转化为氮气的反硝化(DEN)一直是研究的对象。然而，在本研究中，将研究异化硝酸盐还原为铵(DNRA)，这可能在许多水生生态系统中具有重要的定量意义。DNRA不能有效地对抗富营养化，因为产生的铵保存在生态系统中。这项研究的中心目标是对DNRA和DEN进行比较和公平的调查，以便更好地了解控制非生物因素(如硝酸盐、硫化物、有机碳、铁)。在一种新的方法中，将使用微型传感器、凝胶探针和质谱分析DNRA和DEN在沉积物中的垂直分布。硝酸盐还原微生物群落的丰度和活性将用分子技术在功能基因(这里是亚硝酸盐还原酶)的水平上进行研究。使用底栖生物梯度室、天然沉积物和细菌分离物进行的实验室实验结果将在相关现场得到验证。