State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, PR China.
Sci Total Environ. 2019 Dec 1;694:133721. doi: 10.1016/j.scitotenv.2019.133721. Epub 2019 Aug 1.
The use of short-term, fast-acting curative treatments to rapidly suppress the proliferation of upcoming cyanobacterial blooms without negative side effects on overall water quality is important for environmental regulatory agencies. A 15-day in situ mesocosm experiment was conducted to evaluate the effects of algal harvest at different intensities and the effect of hydrogen peroxide on the mitigation of cyanobacterial blooms, subsequent algal growth and phytoplankton community structure. The results indicate that filtration through a 30-μm-pore-size net could remove most of the Microcystis colonies, leading to a decline in algal biomass. However, algal harvest at 30% and 60% intensities tended to promote cyanobacterial growth under nutrient-replete conditions, and the mitigation effect only lasted a few days, since cyanobacteria biomass exhibited no significant difference between the control and those two treatments on Day 6. When the algal harvest intensity was 90%, the cyanobacterial biomass remained at a relatively low level for 15 days. The average Microcystis colony size rapidly returned to the initial level after an initial decline across all the algal harvest intensities, indicating that algal harvest should be repeatedly performed within a short time period to mitigate Microcystis blooms. Furthermore, removing Microcystis colonies by filtration led to increased diversity in the phytoplankton community, as the proportion of non-Microcystis cyanobacteria increased with harvest intensity. This result might pose a challenge for cyanobacterial bloom control over the long term if filamentous cyanobacteria become dominant. The 10.0 mg L HO treatment selectively suppressed cyanobacteria throughout the experimental period, leading to succession from a cyanobacteria-dominated to a Chlorophyta-dominated community after Day 9. Overall, using hydrogen peroxide is more effective than algal harvesting as a one-time quick curative measure.
短期、速效的治疗方法对于抑制即将爆发的蓝藻水华的增殖至关重要，同时又不会对整体水质产生负面影响，这对环境监管机构来说非常重要。本研究进行了为期 15 天的原位中观实验，以评估不同强度的藻类收割和过氧化氢对缓解蓝藻水华、随后藻类生长和浮游植物群落结构的影响。结果表明，通过 30μm 孔径的网过滤可以去除大部分微囊藻聚集体，从而降低藻类生物量。然而，在营养充足的条件下，30%和 60%强度的藻类收割往往会促进蓝藻的生长，并且缓解效果仅持续几天，因为在第 6 天，对照组和这两个处理组之间的蓝藻生物量没有显著差异。当藻类收割强度为 90%时，蓝藻生物量在 15 天内仍保持在相对较低的水平。在所有藻类收割强度下，微囊藻聚集体的平均大小在最初下降后迅速恢复到初始水平，这表明在短时间内应该反复进行藻类收割以缓解微囊藻水华。此外，通过过滤去除微囊藻聚集体会增加浮游植物群落的多样性，因为随着收割强度的增加，非微囊藻蓝藻的比例增加。如果丝状蓝藻占优势，这一结果可能会对蓝藻水华的长期控制构成挑战。10.0mg/L 的 HO 处理在整个实验期间选择性地抑制了蓝藻，导致在第 9 天之后从蓝藻占优势的群落演替为以绿藻占优势的群落。总的来说，与藻类收割相比，作为一次性快速治疗方法，使用过氧化氢更为有效。
