Multi-proxy approaches to investigate cyanobacteria invasion from a eutrophic lake into the circumjacent groundwater.
Multi-proxy approaches to investigate cyanobacteria invasion from a eutrophic lake into the circumjacent groundwater.
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DOI：
10.1016/j.watres.2021.117578
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发表时间：
2021-08
期刊：
影响因子：
12.8
通讯作者：
S. Ye;Li Gao;A. Zamyadi;Caitlin M. Glover;N. Ma;Haiming Wu;Ming Li
中科院分区：
文献类型：
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作者：
S. Ye;Li Gao;A. Zamyadi;Caitlin M. Glover;N. Ma;Haiming Wu;Ming Li
为了验证蓝藻是否可以从富营养化湖泊进入周围的地下水，在太湖（中国）进行了大规模的现场调查，实验室培养和石英柱渗透试验。16 S rRNA基因扩增子的高通量测序表明，蓝藻操作分类单位（OTU）存在于15的40个总威尔斯在四个主要方向在不同的距离从太湖海岸，最大的43公里。共检测到微囊藻属（Microcystis）、长孢藻属（Dolichospermum）、席藻属（Phormidium）、细鳞藻属（Leptolyngbya）、假单胞藻属（Pseudanabaena）和聚球藻属（Synechococcus）6个蓝藻属。席藻、微囊藻和集球藻在蓝藻群落中所占比例分别为45.2%、32.2%和19.4%。qRT-PCR结果表明，太湖蓝藻丰度随距离海岸的增加而降低。通过对地下水接种培养物的显微分析，发现了微囊藻属、长孢藻属和席藻属。五个蓝藻属能够穿透填充有100 - 200 μm的石英颗粒的柱。发现石英砂的更细的层是不可渗透的。渗透能力大小依次为微囊藻>集球藻>念珠藻>席藻>拟绒毡藻。地下水样本中发现微囊藻毒素浓度不足（< 1 µg L−1）。综合太湖蓝藻、周边地下水、藻类土壤结皮等因素，推测微囊藻可能来源于太湖。但席藻可能来源于土壤渗透。这些结果表明，蓝藻及其毒素可以在地下水中传播，但这是一个大小依赖的机制。
To verify whether cyanobacteria can travel from eutrophic lakes into the surrounding groundwater, a large-scale field investigation, laboratorial incubations, and quartz column penetration tests were carried out in Lake Taihu (China). High-throughput sequencing of 16S rRNA gene amplicons indicated that cyanobacteria operational taxonomic units (OTUs) were present at fifteen out of forty total wells in four cardinal directions at varying distances from the shore of Lake Taihu, up to a maximum of forty-three kilometers. Six cyanobacteria genera were detected includingMicrocystis, Dolichospermum, Phormidium, Leptolyngbya, Pseudanabaena and Synechococcus. The proportions of Phormidium, Microcystis and Synechococcus OTUs in the total cyanobacterial community were 45.2%, 32.2% and 19.4%, respectively. The qRT-PCR results showed that cyanobacterial abundance decreased with increasing distance from the shore of Lake Taihu. Based on the microscopic analysis of cultures inoculated with groundwater, we found Microcystis, Dolichospermum and Phormidium. Five cyanobacterial genera were able to penetrate columns filled with quartz particles ranging from 100∼200 μm. Finer layers of quartz sands were found to be impenetrable. The rating of infiltration capabilities was Microcystis > Synechococcus > Nostoc > Phormidium > Cylindrospermopsis. Deficient concentrations of microcystins were found (< 1 µg L−1) in the groundwater samples. Based on the consideration of different factors (cyanobacterial composition in Lake Taihu, peripheral groundwater, and algal soil crusts), it was deduced that Microcystis likely originated from the lake. Still, Phormidium was probably originated from the soil infiltration. These results suggest that cyanobacteria and their toxins could travel in the groundwater, but this is a size-dependent mechanism.