State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
Water Res. 2022 Jul 15;220:118670. doi: 10.1016/j.watres.2022.118670. Epub 2022 May 25.
In comparison with the middle- and high-latitude regions, the low-latitude regions are less associated with the occurrence of 2-methylisoborneol (MIB) episodes, since most of the previously identified MIB producers favor moderate/low light/temperature conditions. Here, we report a serious MIB outbreak over the period from Jul. 2018 to Jun. 2019 in a low-latitude reservoir with a mean annual water temperature of 25.6 °C. The MIB episode lasted for a long period, from Jul. 2018 to Jan. 2019, and Planktothricoides raciborskii was confirmed to be the main MIB producer. The growth characteristics of P. raciborskii were explored through both laboratory culturing and on-site verification experiments. The results indicated that this strain was not nutrient-sensitive at TN > 800 μg L and TP > 10 μg L, but favored moderate light intensity (54 μmol photon m·s) and high temperature (30 °C). The two bloom-forming genera, Limnothrix and Aphanizomenon, favoring lower temperature and similar or relatively higher light intensity, showed much greater proliferation, about 13 folds (Limnothrix) and 58 folds (Aphanizomenon), from Dec. to Jun.; by contrast, the high water temperature (29.9 ± 2.8 °C) and light intensity (189.1 ± 87.6 μmol photon m·s) from Jul. to Nov. were not favorable to Limnothrix or Aphanizomenon, which might have created an opportunity for the growth of MIB-producing P. raciborskii. In addition, we also found that high temperature could promote the release of MIB from P. raciborskii cells, therefore exerting increased pressure on drinking water treatment processes.
与中高纬度地区相比，低纬度地区与 2-甲基异莰醇（MIB）事件的发生关联较少，因为大多数先前鉴定的 MIB 产生菌都喜欢中低光照/温度条件。在这里，我们报告了一个低纬度水库在 2018 年 7 月至 2019 年 6 月期间发生的严重 MIB 爆发，该水库的年平均水温为 25.6°C。MIB 爆发持续时间长，从 2018 年 7 月到 2019 年 1 月，并且确认 P. raciborskii 是主要的 MIB 产生菌。通过实验室培养和现场验证实验，探索了 P. raciborskii 的生长特性。结果表明，该菌株在 TN>800μg L 和 TP>10μg L 时并不敏感，但喜欢中等光照强度（54μmol 光子 m·s）和高温（30°C）。两种水华形成属， Limnothrix 和 Aphanizomenon，较适合较低的温度和相似或相对较高的光照强度，在 12 月至 6 月期间繁殖能力大大增强，约为 13 倍（Limnothrix）和 58 倍（Aphanizomenon）；相比之下，7 月至 11 月的高温（29.9±2.8°C）和光照强度（189.1±87.6μmol 光子 m·s）对 Limnothrix 或 Aphanizomenon 不利，这可能为 MIB 产生菌 P. raciborskii 的生长创造了机会。此外，我们还发现高温可以促进 P. raciborskii 细胞释放 MIB，因此对饮用水处理过程施加了更大的压力。
