Phytoplankton community structure in Lake Buchanan, TX, during an extended drought, Central Texas, USA (2010-2015)

This study investigated the impacts of an extended, severe drought in Central Texas, USA, from 2010-2015 by assessing the potential for cyanobacterial harmful algal blooms (CyanoHABs) related to drought conditions. Water samples were collected from 2013 to 2017 to evaluate water quality and preserved microalgae were used to estimate cellular biovolume of major taxa; live samples were collected in the summer of 2017 and individual microalgal cells/filaments were isolated for DNA barcoding. rDNA sequencing confirmed the presence of bloom-forming cyanobacteria, most notably those with the potential of producing saxitoxins, microcystins, and anatoxins. Based on cell counts and sequencing results, Planktothrix, Chrysosporum, and Raphidiopsis thrived in drought conditions whereas Limnothrix and Pseudanabaena were dominant post-drought. Following the drought period, Chrysosporum ovalisporum, Phormidium tenue, and Planktothrix sp. were still present, however the community had shifted to predominantly diatoms, e.g., Fragilaria and Lindavia. These observations suggest drought conditions may promote the success of potentially toxic cyanobacteria. This dataset includes consensus sequences for CyanoITS, ITS2, 23S, and 18S aligned using Geneious and cellular biovolumes using protocols described in Gamez et al. 2022.

本研究针对美国德克萨斯州中部2010至2015年的持续性严重干旱展开研究，通过评估与干旱条件相关的蓝藻有害藻华（cyanobacterial harmful algal blooms, CyanoHABs）发生潜力，探究该干旱事件的生态影响。研究团队于2013至2017年采集水样以评估水质，通过保存的微藻样品估算主要藻类类群的细胞生物体积；2017年夏季采集鲜活水样，分离单个微藻细胞/丝状体用于DNA条形码分析。核糖体DNA（rDNA）测序证实了产藻华蓝藻的存在，其中尤以具备合成石房蛤毒素、微囊藻毒素及鱼腥藻毒素能力的类群最为突出。基于细胞计数与测序结果，浮游蓝丝藻属（Planktothrix）、金囊藻属（Chrysosporum）和拟柱孢藻属（Raphidiopsis）在干旱期大量繁殖，而湖丝藻属（Limnothrix）与假鱼腥藻属（Pseudanabaena）则在干旱后期成为优势类群。干旱结束后，卵形金囊藻（Chrysosporum ovalisporum）、柔弱席藻（Phormidium tenue）及未定种浮游蓝丝藻（Planktothrix sp.）仍有留存，但藻类群落已转变为以硅藻为主，例如脆杆藻属（Fragilaria）与林德藻属（Lindavia）。上述观测结果表明，干旱环境可能促进潜在产毒蓝藻的种群繁盛。本数据集包含使用Geneious软件比对得到的CyanoITS、ITS2、23S及18S基因共识序列，以及参照Gamez等人2022年研究中描述的实验方法测定的细胞生物体积数据。