Differential responses of marine, mesohaline and oligohaline bacterial communities to the addition of terrigenous carbon
Differential responses of marine, mesohaline and oligohaline bacterial communities to the addition of terrigenous carbon
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DOI：
10.1111/1462-2920.13784
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发表时间：
2017-08-01
影响因子：
5.1
通讯作者：
Juergens, K.
中科院分区：
文献类型：
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作者：
Herlemann, D. P. R.;Manecki, M.;Juergens, K.
为了应对全球变暖，越来越多的tDOM通过河口从陆地运往海洋。在这项研究中，我们研究了波罗的海特有的三种盐度(盐度：32、7和3)下，微生物对tDOM浓度增加的响应。在5月和11月进行的中游实验显示，溶解有机碳(DOC)利用率较低(0-6%)。使用超高分辨率质谱仪的分子DOM分析确认了tDOM操作中的陆源信号，但在实验过程中DOM水平的分子变化是微妙的。然而，tDOM对低盐系膜细菌的产生有显著的刺激作用。培养7天和11天后，细菌群落组成的变化在tDOM修正的海洋和中盐生附着体中尤为明显，但在低盐生附着体中变化不明显。这些结果表明低盐细菌群落固有的适应高tDOM浓度的能力，从而利用tDOM。在含有紫外线处理的tDOM的系膜中，细菌活性和DOC的去除率较高，这支持了光诱导的、改性的tDOM的生物利用度的提高。微生物tDOM利用率总体较低，突显了非生物因素在决定河口tDOM分布和动态方面的重要性。
In response to global warming, increasing quantities of tDOM are transported through estuaries from land to the sea. In this study, we investigated microbial responses to increased tDOM concentrations in three salinity regimes (salinity: 32, 7 and 3) characteristic of the Baltic Sea. Mesocosm experiments performed in May and November revealed low (0-6%) dissolved organic carbon (DOC) utilisation. Molecular DOM analyses using ultrahigh-resolution mass spectrometry identified the terrigenous signal in the tDOM manipulation, but the molecular changes in DOM levels over the course of the experiment were subtle. However, tDOM had significant stimulatory effects on bacterial production in the oligohaline mesocosms. The shift in the bacterial community composition was especially prominent in the tDOM-amended marine and mesohaline mesocosms, but not in the oligohaline mesocosms after 7 and 11 days of incubation. These results suggested the inherent ability of oligohaline bacterial communities to adapt to high tDOM concentrations and therefore to use tDOM. The higher rates of bacterial activity and DOC removal in mesocosms containing UV-pretreated tDOM supported the increased bioavailability of photoinduced, modified tDOM. The overall low rates of microbial tDOM utilisation highlights the importance of abiotic factors in determining the distribution and dynamics of tDOM in estuaries.