Sediment denitrification in Yangtze lakes is mainly influenced by environmental conditions but not biological communities
Sediment denitrification in Yangtze lakes is mainly influenced by environmental conditions but not biological communities
复制标题
长江湖泊底泥反硝化主要受环境条件影响，而非生物群落影响
DOI：
10.1016/j.scitotenv.2017.10.221
复制
发表时间：
2018-03-01
影响因子：
9.8
通讯作者：
Liu, Guihua
中科院分区：
文献类型：
--
作者：
Liu, Wenzhi;Yao, Lu;Liu, Guihua
在全球范围内，浅水湖泊遭受过量的氮（N）负荷，由于在集水区人类活动的增加，导致水质退化和水生生物多样性的损失。沉积物反硝化作用将硝酸盐还原为氮的气态产物，是淡水湖泊氮永久去除的最重要机制。然而，非生物和生物因素对沉积物反硝化作用的相对贡献是高度可变的。本文测定了长江流域22个富营养化湖泊74个沉积物样品的反硝化速率和氧化亚氮（N2 O）产生速率。我们还使用nirK和nirS基因量化了生物群落的多样性和丰富性。方差分配分析结果表明，水的理化性质（如，溶解氧）和营养物（例如，NO3-浓度是影响反硝化和N2 O产生速率的主要因素，而硝化菌群落和沉水植被不是主要因素。通径分析进一步表明，水体理化性质和营养盐对反硝化和N2 O产生速率均有直接和间接影响，且直接影响显著高于沉积物特性、浮游生物群落和沉水植被的间接影响。这些结果表明，在长江湖泊氮的去除过程中占主导地位的是非生物因素，而不是多样性和丰富的水生植物和水生植物。此外，本研究的结果有助于制定有针对性的策略，以评估和提高在中国富营养化湖泊的脱氮能力。(c)2017爱思唯尔B. V.保留所有权利。
Globally, shallow lakes have suffered from excessive nitrogen (N) loading due to increased human activities in catchments, resulting in water quality degradation and aquatic biodiversity loss. Sediment denitrification, which reduces nitrate (NO3-) to N gaseous products, is the most important mechanism for permanent N removal in freshwater lakes. However, the relative contribution of abiotic and biotic factors to the sediment denitrification is highly variable. Here, we determined the unamended denitrification rate and nitrous oxide (N2O) production rate of 74 sediment samples from 22 eutrophic lakes in the Yangtze River basin. We also quantified the diversity and abundance of denitrifying communities using nirK and nirS genes. The results of variance partitioning analyses showed that water physicochemical properties (e.g., dissolved oxygen) and nutrients (e.g., NO(3)(-)concentration) but not denitrifier communities and submerged vegetation were the major factor groups predicting denitrification and N2O production rates. Path analyses further revealed that water physicochemical properties and nutrients could affect denitrification and N2O production rates both directly and indirectly, and the direct effects were considerably higher than the indirect effects mediated through changes in sediment characteristics, denitrifier communities and submerged vegetation. These findings suggest that the dominant N removal process in Yangtze lakes is largely regulated by abiotic factors rather than diversity and abundance of denitrifiers and submerged macrophytes. Additionally, the findings in this study are helpful in developing a targeted strategy to assess and enhance the N removal capability of eutrophic lakes in China. (c) 2017 Elsevier B.V. All rights reserved.