Distributions, abundances and activities of microbes associated with the nitrogen cycle in riparian and stream sediments of a river tributary
Distributions, abundances and activities of microbes associated with the nitrogen cycle in riparian and stream sediments of a river tributary
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DOI：
10.1016/j.watres.2016.09.048
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发表时间：
2016-12-01
期刊：
影响因子：
12.8
通讯作者：
Ogram, Andrew
中科院分区：
文献类型：
--
作者：
Kim, Haryun;Bae, Hee-Sung;Ogram, Andrew
河流支流是在生态上重要的环境，它充当无机氮的水槽。为了更深入地了解这些环境中的氮循环（N-Cycle），研究了位于佛罗里达北部的Santa Fe River（SFR）支流的河岸和溪流沉积物中涉及N周期中涉及的微生物种群的分布和活动美国。河岸沉积物的特征是有机物含量更高，细胞外酶活性（包括核植物水解酶，β-D-D-葡萄糖苷酶和苯酚氧化酶）比溪流沉积酶。与溪流沉积物相比，河岸沉积物的硝化活性明显较高，反硝化，硝酸盐降低对氨（DNRA）（DNRA）和厌氧氨氧化；相应地，具有较高的AMOA副本（用于列出硝化器的生物标志物），NIRS和NIRK（用于丹尼氏剂）和NRFA（用于DNRA细菌）。在N周期过程中，反硝化显示出最高的活性和最高浓度的相应基因（NIRK和NIRS）拷贝数。在河岸沉积物中，观察到了大量的硝化活性（6.3 mg-n kg土壤（-1）d（-1）平均）和AMOA副本的数量（7.3 x 10（7）拷贝G土壤（-1）的平均水平（-1）平均），并且平均硝化率与非硝化率相关。河岸沉积物中的分解剂和硝化物的公会结构与在溪流沉积物中发现的公会结构有显着差异，如对NIRS和Archaeal AMOA序列的分析所揭示的。这项研究表明，河岸沉积物是农业径流的无机氮负荷的下沉，硝化和硝化剂与碳和氮含量升高以及细胞外酶活性的水平升高有关。 （c）2016 Elsevier Ltd.保留所有权利。
River tributaries are ecologically important environments that function as sinks of inorganic nitrogen. To gain greater insight into the nitrogen cycle (N-cycle) in these environments, the distributions and activities of microbial populations involved in the N-cycle were studied in riparian and stream sediments of the Santa Fe River (SFR) tributaries located in northern Florida, USA. Riparian sediments were characterized by much higher organic matter content, and extracellular enzyme activities, including cellobiohydrolase, beta-D-glucosidase, and phenol oxidase than stream sediments. Compared with stream sediments, riparian sediments exhibited significantly higher activities of nitrification, denitrification, dissimilatory nitrate reduction to ammonia (DNRA) and anaerobic ammonia oxidation; correspondingly, with higher copies of amoA (a biomarker for enumerating nitrifiers), nirS and nirK (for denitrifiers), and nrfA (for DNRA bacteria). Among N-cycle processes, denitrification showed the highest activities and the highest concentrations of the corresponding gene (nirK and nirS) copy numbers. In riparian sediments, substantial nitrification activities (6.3 mg-N kg soil(-1)d(-1) average) and numbers of amoA copies (7.3 x 10(7) copies g soil(-1) average) were observed, and nitrification rates correlate with denitrification rates. The guild structures of denitrifiers and nitrifiers in riparian sediments differed significantly from those found in stream sediments, as revealed by analysis of nirS and archaeal amoA sequences. This study shows that riparian sediments serve as sinks for inorganic nitrogen loads from non-point sources of agricultural runoff, with nitrification and denitrification associated with elevated levels of carbon and nitrogen contents and extracellular enzyme activities. (C) 2016 Elsevier Ltd. All rights reserved.