Nanosilver inhibits nitrification and reduces ammonia-oxidising bacterial but not archaeal amoA gene abundance in estuarine sediments
Nanosilver inhibits nitrification and reduces ammonia-oxidising bacterial but not archaeal amoA gene abundance in estuarine sediments
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DOI：
10.1111/1462-2920.13441
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发表时间：
2017-02-01
影响因子：
5.1
通讯作者：
Whitby, Corinne
中科院分区：
文献类型：
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作者：
Beddow, Jessica;Stolpe, Bjoern;Whitby, Corinne
银纳米颗粒（AgNPs）通过废水处理流出物进入河口，由于其抗菌特性，它们可以抑制微生物。氨氧化细菌（AOB）和古细菌（AOA）参与了硝化的第一步，对生态系统功能非常重要，特别是在污水排放导致高氮输入的情况下。本研究研究了脉冲添加AgNPs对低盐度和中盐性河口沉积物中AOB和AOA氨单加氧酶（amoA）基因丰度和底栖生物硝化电位（NPR）的影响。虽然暴露于0.5 mg L-1 AgNPs对amoA基因丰度或NPR没有显著影响，但50 mg L-1 AgNPs显著降低AOB amoA基因丰度（14天内高达76%），并在一天后显著降低低盐度沉积物中的NPR 20倍，在中盐沉积物中降低2倍。AgNP的行为在不同的地点有所不同，因此在中盐水中发生了更多的聚集（可能是由于盐度较高），这可能降低了毒性。总之，AgNPs有可能减少河口沉积物中的氨氧化，特别是在AgNPs随时间积累并达到高浓度的地方。这可能会导致硝化的长期风险，特别是在氨氧化主要由AOB驱动的多盐河口。
Silver nanoparticles (AgNPs) enter estuaries via wastewater treatment effluents, where they can inhibit microorganisms, because of their antimicrobial properties. Ammonia-oxidising bacteria (AOB) and archaea (AOA) are involved in the first step of nitrification and are important to ecosystem function, especially where effluent discharge results in high nitrogen inputs. Here, we investigated the effect of a pulse addition of AgNPs on AOB and AOA ammonia monooxygenase (amoA) gene abundances and benthic nitrification potential rates (NPR) in low-salinity and mesohaline estuarine sediments. Whilst exposure to 0.5 mg L-1 AgNPs had no significant effect on amoA gene abundances or NPR, 50 mg L-1 AgNPs significantly decreased AOB amoA gene abundance (up to 76% over 14 days), and significantly decreased NPR by 20-fold in low-salinity sediments and by twofold in mesohaline sediments, after one day. AgNP behaviour differed between sites, whereby greater aggregation occurred in mesohaline waters (possibly due to higher salinity), which may have reduced toxicity. In conclusion, AgNPs have the potential to reduce ammonia oxidation in estuarine sediments, particularly where AgNPs accumulate over time and reach high concentrations. This could lead to long-term risks to nitrification, especially in polyhaline estuaries where ammonia-oxidation is largely driven by AOB.