Artificial ponds as hotspots of nitrogen removal in agricultural watershed
Artificial ponds as hotspots of nitrogen removal in agricultural watershed
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人工池塘成为农业流域脱氮热点
DOI：
10.1007/s10533-022-00928-6
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发表时间：
2022-04-21
期刊：
影响因子：
4
通讯作者：
Wang，Yu
中科院分区：
文献类型：
--
作者：
Cai，Min;Li，Shuai;Wang，Yu
小水域，如池塘，是最丰富的淡水环境，越来越多地认识到它们在生态系统服务提供中的作用。在农业流域，人工池塘在减少氮素污染方面起着至关重要的作用。然而，到目前为止，人工池塘仍然是水环境中研究最少的部分。微生物活动的重要性很少被讨论，这使得人们对微生物在脱氮中的途径和过程速度知之甚少。为了说明人工池塘在农业流域微生物脱氮中的作用，在中国的一个农业流域采集了21个池塘沉积物和11个土壤。结果表明，池塘表层沉积物的溶解无机氮(9.1~21.9g/kg)和总有机质(64.8g/kg~113.0 mg/kg)明显高于周围农田土壤。池塘的微生物脱氮率较高(12.4~25.5nmol.N g−1h−1)，是旱地土壤的2~9倍。在池塘沉积物中，反硝化作用在微生物脱氮过程中占主导地位(>； 90%N损失)，厌氧氨氧化的贡献很小。随着氮的快速去除，池塘中N2O的产生潜力很高(高达9.4nmoL/N g−1h−1)。对于反硝化基因，nirgene总是比nosZ基因更丰富。此外，在水淹条件下，irSgene的含量更丰富，而irKgene在旱地更喜欢较高的溶解氧和NO3−。这些发现突出了农业流域池塘的生态功能，为污染控制和全球氮循环提供了新的思路。
Small waters, like ponds, are the most abundant freshwater environments, and are increasingly recognized for their function in ecosystem service delivery. In agricultural watershed, artificial ponds play an essential role in reducing nitrogen pollution. However, until now artificial ponds remain the least investigated part of water environments. The importance of microbial activities has seldom been discussed, which makes the microbial pathways and processes rates in nitrogen removal poorly understood. To illustrate the role of artificial ponds in microbial nitrogen removal in agricultural watersheds, 21 pond sediments and 11 soils are collected in an agricultural watershed of China. Results show that surface sediments in ponds carry significantly higher dissolved inorganic nitrogen (9.1–21.9 mg/kg) and total organic matter (64.8–113.0 g/kg) compared to the surrounding agricultural soils. High rates of microbial nitrogen removal in ponds (12.4–25.5 nmol N g−1h−1) are observed, which are 2–9 times higher than those in dryland soils. In pond sediments, denitrification dominates (> 90% N-loss) the microbial nitrogen removal process with only a minor contribution of anaerobic ammonium oxidation. A high potential of N2O production (up to 9.4 nmol N g−1h−1) occurs in ponds along with the rapid nitrogen removal. For denitrifier genes,nirgene are always more abundant thannosZgene. Additionally, thenirSgene is more abundant under flooded conditions, whilenirKgene prefers higher dissolved oxygen and NO3−in drylands. These findings highlight the ecosystem function of ponds in agricultural watersheds, and provide new ideas on pollution control and global nitrogen cycling.