Several studies have shown that large, experimental additions of nitrate (NO₃) to eutrophic systems can mitigate large populations of nuisance cyanobacteria and that high NO₃ concentrations can oxidize anoxic sediments. These studies are consistent with observations from numerous aquatic systems across a broad trophic range showing development of reduced surficial sediments precedes the formation of large cyanobacteria populations. We use 50+ years of data to explore whether high NO₃ concentrations may have been instrumental both in the absence of large populations of cyanobacteria in eutrophic Hamilton Harbour, Lake Ontario in the 1970s when total phosphorus (TP) and total nitrogen (TN) concentrations were high, and in delaying large populations until August and September in recent decades despite much lower TP and TN. Our results indicate that large cyanobacteria population events do not occur at the central station in July-September when epilimnetic NO₃ > 2.2 mg N L⁻¹. The results further suggest that remedial improvements to wastewater treatment plant oxidation capacity may have been inadvertently responsible for high NO₃ concentrations > 2.2 mg N L⁻¹ and thus for mitigating large cyanobacteria populations. This also implies that large cyanobacteria populations may form earlier in the summer if NO₃ concentrations are lowered.

几项研究表明，在富营养化系统中大量实验性地添加硝酸盐 (NO ₃ ) 可以减轻大量有害蓝细菌，而高浓度的 NO ₃可以氧化缺氧沉积物。这些研究与来自广泛营养范围的众多水生系统的观察结果一致，表明减少的地表沉积物的发展先于大型蓝藻种群的形成。我们用 50+ 年的数据来探索高 NO ₃1970 年代，当总磷 (TP) 和总氮 (TN) 浓度很高时，富营养化的安大略湖汉密尔顿港缺乏大量蓝藻种群，以及将大量蓝藻种群推迟到 8 月和 9 月近几十年，尽管 TP 和 TN 低得多。我们的研究结果表明，7 月至 9 月在中央站不发生大型蓝藻种群事件，此时表层凝液 NO ₃  > 2.2 mg NL ^-1 。结果进一步表明，废水处理厂氧化能力的补救改进可能无意中导致高 NO ₃浓度 > 2.2 mg NL ^-1从而减少大量蓝藻种群。这也意味着如果 NO ₃浓度降低，则可能在夏季早些时候形成大量蓝藻种群。