Department of Integrative Biology, University of California, Berkeley, California, United States of America.
Ocean Sciences Department, University of California, Santa Cruz, California, United States of America.
PLoS One. 2018 May 18;13(5):e0197669. doi: 10.1371/journal.pone.0197669. eCollection 2018.
Benthic algae fuel summer food webs in many sunlit rivers, and are hotspots for primary and secondary production and biogeochemical cycling. Concerningly, riverine benthic algal assemblages can become dominated by toxic cyanobacteria, threatening water quality and public health. In the Eel River in Northern California, over a dozen dog deaths have been attributed to cyanotoxin poisonings since 2000. During the summers of 2013-2015, we documented spatial and temporal patterns of cyanotoxin concentrations in the watershed, showing widespread distribution of anatoxin-a in benthic cyanobacterial mats. Solid phase adsorption toxin tracking (SPATT) samplers were deployed weekly to record dissolved microcystin and anatoxin-a levels at 10 sites throughout the watershed, and 187 Anabaena-dominated or Phormidium-dominated cyanobacterial mat samples were collected from 27 locations to measure intracellular anatoxin-a (ATX) and microcystins (MCY). Anatoxin-a levels were higher than microcystin for both SPATT (mean MCY = 0.8 and ATX = 4.8 ng g resin-1 day-1) and cyanobacterial mat samples (mean MCY = 0.074 and ATX = 1.89 μg g-1 DW). Of the benthic mats sampled, 58.9% had detectable anatoxin-a (max = 70.93 μg g-1 DW), while 37.6% had detectable microcystins (max = 2.29 μg g-1 DW). SPATT cyanotoxin levels peaked in mid-summer in warm mainstem reaches of the watershed. This is one of the first documentations of widespread anatoxin-a occurrence in benthic cyanobacterial mats in a North American watershed.
底栖藻类为许多阳光充足的河流中的夏季食物网提供燃料，是初级和次级生产以及生物地球化学循环的热点。令人担忧的是，河流底栖藻类组合可能会被有毒蓝藻主导，威胁到水质和公共健康。在加利福尼亚州北部的鳗鱼河中，自 2000 年以来，已有十几只狗因蓝藻毒素中毒而死亡。在 2013-2015 年的夏季，我们记录了流域中蓝藻毒素浓度的时空模式，显示出底栖蓝藻菌席中广泛分布的鱼腥藻毒素-a。固相吸附毒素跟踪 (SPATT) 采样器每周部署一次，以记录整个流域 10 个地点的溶解微囊藻毒素和鱼腥藻毒素-a 水平，从 27 个地点采集了 187 个由 Anabaena 或 Phormidium 主导的蓝藻菌席样本，以测量细胞内鱼腥藻毒素-a (ATX) 和微囊藻毒素 (MCY)。SPATT（平均 MCY=0.8 和 ATX=4.8ng g 树脂-1 day-1）和蓝藻菌席样本（平均 MCY=0.074 和 ATX=1.89μg g-1 DW）的鱼腥藻毒素-a 水平均高于微囊藻毒素。在所采样的底栖菌席中，有 58.9%检测到鱼腥藻毒素-a（最大值为 70.93μg g-1 DW），而有 37.6%检测到微囊藻毒素（最大值为 2.29μg g-1 DW）。SPATT 蓝藻毒素水平在夏季中期达到顶峰，此时是流域温暖的干流段。这是北美流域中首次记录到广泛存在底栖蓝藻菌席中的鱼腥藻毒素-a。
