Benthic cyanobacteria in lakes and rivers: distribution, abundance, implications

科学界和媒体最近都把重点放在水生蓝藻上，因为它们极大地影响了湖泊和河流的娱乐和用水。底栖物种和阶段大多被忽略，因为它们只有在上升到水面时才能看到。然而，越来越多的证据表明，底栖蓝藻在固碳固氮中发挥着重要作用。此外，它们还可能影响营养链和供水，因为它们与无脊椎动物相互作用，引发有害的水华，释放毒素和产生气味的代谢物。在这项研究中，我建议1）量化的物理和化学的水特性的分布和丰富的底栖蓝藻和2）研究它们的存在对水资源的影响仍然知之甚少的作用。我将在两个环境中追求这些目标，其中底栖蓝藻特别相关：A）我们最近报道了在圣劳伦斯河的河流湖泊中存在大量有毒丝状蓝藻Lyngbya wollei，它覆盖了大约50平方公里的河底。本研究的目的是建立L.沃莱增殖。这些知识在圣劳伦斯河的管理中将是重要的，因为商业和休闲渔业可能已经受到水生维管植物和与L. wollei。毒素以及味道和气味化合物的释放可能会增加为数百万人口服务的水过滤厂的处理成本。B）在蒙特利尔北部劳伦地区的几个湖泊中，尽管营养物浓度较低，但蓝藻水华越来越多。我们将测试这些水华是否开始在沿岸的区，底栖阶段可能会开始利用湖泊周围的土地开发造成的沉积物-水界面的营养供应增加的优势，他们的增长。了解娱乐湖泊有害水华的潜在机制将有助于保护加拿大遗产和水资源的这些重要组成部分的质量。

Both the scientific community and the media have recently focused on planktonic cyanobacteria because they greatly affect the use of lakes and rivers for the purposes of recreation and water consumption. Benthic species and stages are mostly ignored because they are only visible when they rise to the water surface. Nevertheless, there is increasing evidence that benthic cyanobacteria play an important role in carbon and nitrogen fixation. Moreover, they may affect the trophic chain and the water supply by interacting with invertebrates, initiating harmful planktonic blooms and releasing toxins and odour-producing metabolites. In this research, I propose to 1) quantify the still poorly understood role of physical and chemical water characteristics on the distribution and abundance of benthic cyanobacteria and 2) examine the implications of their presence for water resources. I will pursue these objectives in two environments where benthic cyanobacteria are especially relevant: A) We recently reported the presence of a significant amount of the noxious filamentous cyanobacterium Lyngbya wollei in the fluvial lakes of the St. Lawrence River, where it covers roughly 50 km2 of the river bottom. This research aims to model the temporal and spatial dynamics of L. wollei proliferation. This knowledge will be important in the management of the St. Lawrence River, as the commercial and recreational fishery may already be affected by the reduction in aquatic vascular plants and associated invertebrates linked to the spread of L. wollei. The release of toxins and taste and odour compounds may increase treatment costs for water filtration plants serving a population of several million. B) Cyanobacterial blooms are increasingly observed in several lakes of the Laurentian region north of Montréal, despite low nutrient concentrations. We will test whether these blooms initiate in the littoral zone, where benthic stages may start their growth by taking advantage of the increased nutrient supply at the sediment-water interface resulting from land development around the lakes. An understanding of the mechanisms underlying harmful blooms in recreational lakes will help preserve the quality of these important elements of Canada's heritage and water resources.