Microbial Ecology and Limnic Microbiology, University of Konstanz, 78457 Konstanz, Germany.
Human and Environmental Toxicology, University of Konstanz, 78457 Konstanz, Germany.
Toxins (Basel). 2021 Sep 17;13(9):666. doi: 10.3390/toxins13090666.
Recurring blooms of filamentous, red-pigmented and toxin-producing cyanobacteria have been reported in numerous deep and stratified prealpine lakes, with the exception of Lake Constance. In a 2019 and 2020 Lake Constance field campaign, we collected samples from a distinct red-pigmented biomass maximum below the chlorophyll-a maximum, which was determined using fluorescence probe measurements at depths between 18 and 20 m. Here, we report the characterization of these deep water red pigment maxima (DRM) as cyanobacterial blooms. Using 16S rRNA gene-amplicon sequencing, we found evidence that the blooms were, indeed, contributed by spp., although phycoerythrin-rich taxa constituted most of the biomass (>96% relative read abundance) of the cyanobacterial DRM community. Through UPLC-MS/MS, we also detected toxic microcystins (MCs) in the DRM in the individual sampling days at concentrations of ≤1.5 ng/L. Subsequently, we reevaluated the fluorescence probe measurements collected over the past decade and found that, in the summer, DRM have been present in Lake Constance, at least since 2009. Our study highlights the need for a continuous monitoring program also targeting the cyanobacterial DRM in Lake Constance, and for future studies on the competition of the different cyanobacterial taxa. Future studies will address the potential community composition changes in response to the climate change driven physiochemical and biological parameters of the lake.
已在众多深而分层的高山前湖泊中报告了丝状、红色和产毒蓝藻的反复大量繁殖，但康斯坦茨湖除外。在 2019 年和 2020 年的康斯坦茨湖实地考察中，我们从叶绿素-a 最大值以下的独特红色色素生物量最大值处采集了样本，该最大值是通过在 18 至 20 米深度的荧光探针测量确定的。在这里，我们将这些深水红色色素最大值 (DRM) 描述为蓝藻大量繁殖。使用 16S rRNA 基因扩增子测序，我们发现证据表明，这些大量繁殖确实是由 spp. 贡献的，尽管富含藻红蛋白的 类群构成了蓝藻 DRM 群落的大部分生物量（>96%的相对读值丰度）。通过 UPLC-MS/MS，我们还在各个采样日的 DRM 中检测到了微囊藻毒素 (MCs)，浓度为≤1.5ng/L。随后，我们重新评估了过去十年收集的荧光探针测量数据，发现自 2009 年以来，至少在夏季，康斯坦茨湖就存在 DRM。我们的研究强调了需要进行持续监测计划，也需要针对康斯坦茨湖的蓝藻 DRM 进行监测，并对不同蓝藻类群的竞争进行未来研究。未来的研究将解决由于气候变化驱动的湖泊理化和生物学参数而导致的潜在群落组成变化。
