School of Environment and Sustainability, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
Department of Physical and Environmental Sciences, University of Toronto, Toronto, Ontario, Canada.
Glob Chang Biol. 2023 Sep;29(18):5240-5249. doi: 10.1111/gcb.16838. Epub 2023 Jul 6.
Cyanobacterial blooms pose a significant threat to water security, with anthropogenic forcing being implicated as a key driver behind the recent upsurge and global expansion of cyanobacteria in modern times. The potential effects of land-use alterations and climate change can lead to complicated, less-predictable scenarios in cyanobacterial management, especially when forecasting cyanobacterial toxin risks. There is a growing need for further investigations into the specific stressors that stimulate cyanobacterial toxins, as well as resolving the uncertainty surrounding the historical or contemporary nature of cyanobacterial-associated risks. To address this gap, we employed a paleolimnological approach to reconstruct cyanobacterial abundance and microcystin-producing potential in temperate lakes situated along a human impact gradient. We identified breakpoints (i.e., points of abrupt change) in these time series and examined the impact of landscape and climatic properties on their occurrence. Our findings indicate that lakes subject to greater human influence exhibited an earlier onset of cyanobacterial biomass by 40 years compared to less-impacted lakes, with land-use change emerging as the dominant predictor. Moreover, microcystin-producing potential increased in both high- and low-impact lakes around the 1980s, with climate warming being the primary driver. Our findings chronicle the importance of climate change in increasing the risk of toxigenic cyanobacteria in freshwater resources.
蓝藻水华对水安全构成重大威胁，人为强迫被认为是现代蓝藻爆发和全球扩张的关键驱动因素。土地利用变化和气候变化的潜在影响可能导致蓝藻管理中出现复杂、更不可预测的情况，特别是在预测蓝藻毒素风险时。人们越来越需要进一步研究刺激蓝藻毒素的具体胁迫因素，并解决蓝藻相关风险的历史或当代性质的不确定性。为了解决这一差距，我们采用古湖泊学方法来重建沿人类影响梯度的温带湖泊中蓝藻丰度和产微囊藻毒素潜力。我们确定了这些时间序列中的转折点（即突然变化点），并研究了景观和气候特性对它们发生的影响。我们的研究结果表明，与受影响较小的湖泊相比，受人类影响更大的湖泊中的蓝藻生物量提前了 40 年出现，土地利用变化成为主要的预测因素。此外，高影响和低影响湖泊中的产微囊藻毒素潜力在 20 世纪 80 年代左右都有所增加，气候变暖是主要驱动因素。我们的研究结果记录了气候变化在增加淡水资源中产毒蓝藻风险方面的重要性。
