High-resolution temporal detection of cyanobacterial blooms in a deep and oligotrophic lake by high-frequency buoy data
High-resolution temporal detection of cyanobacterial blooms in a deep and oligotrophic lake by high-frequency buoy data
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利用高频浮标数据对深部贫营养湖中的蓝藻水华进行高分辨率时间检测
DOI：
10.1016/j.envres.2021.111848
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发表时间：
2022
影响因子：
8.3
通讯作者：
Jiang C.
中科院分区：
文献类型：
--
作者：
Zhang M.;Zhang Y.;Deng J.;Liu M.;Zhou Y.;Zhang Y.;Shi K.;Jiang C.
蓝藻华在全球范围内的规模、频率和持续时间都在增加。然而，由于蓝藻华的高时空变异性，我们对蓝藻华的动力学和驱动机制的了解仍然有限。为确定低营养化湖泊蓝藻爆发的潜在驱动机制，采集了2016年早春千岛湖高频率叶绿素荧光（ChlF）深度剖面和同步水质、水文气象资料。Morisita指数显示，ChlF的垂直分布呈现“聚集”和“离散”两种分布模式，聚集的ChlF在热分层时期呈现地表下叶绿素最大值。ChlF浓度与水温正相关，与浊度负相关。ChlF垂直结构参数（如Morisita指数、地下叶绿素最大深度和厚度）与热分层参数（如混合层深度和相对水柱稳定性）之间存在显著的线性关系。暴雨洪涝后，ChlF格局突然由“聚集型”转变为“离散型”，ChlF浓度<1μg/L持续7 ~ 11 d，混合深度层和浊度显著增加。结果表明，蓝藻华与深层低营养湖泊的热分层和暴雨洪水密切相关。热分层通过提高水温、增强光的可利用性和限制浮游植物的垂直分布来促进表层浮游植物的积累。暴雨洪水通过破坏热分层和减少可用光来中断积累。此外，风速和气温都通过影响热分层来调节浮游植物的动态。我们的研究量化了蓝藻水华动态及其与环境因子的关系，提高了我们对蓝藻水华驱动机制的认识，以保护湖泊饮用水安全和水生生物健康。
Cyanobacterial blooms are increasing in magnitude, frequency, and duration worldwide. However, our knowledge of cyanobacterial blooms dynamics and driving mechanisms is still limited due to their high spatiotemporal variability. To determine the potential driving mechanisms of cyanobacterial blooms in oligotrophic lakes, we collected a high-frequency depth profile of chlorophyll fluorescence (ChlF) and synchronous water quality, hydrometeorological data in early spring 2016 in oligotrophic Lake Qiandaohu. The vertical distribution of ChlF exhibited two patterns, “aggregated” and “discrete”, using Morisita's index, and the aggregated ChlF presented subsurface chlorophyll maxima during the thermal stratification period. The ChlF concentration was positively correlated with water temperature and negatively correlated with turbidity. Significantly linear relationships were observed between ChlF vertical structure parameters (e.g., Morisita's index, subsurface chlorophyll maxima depth and thickness) and thermal stratification parameters (e.g., mixing layer depth and relative water column stability). After rainstorm floods, the ChlF pattern suddenly change from “aggregated” to “discrete” and a ChlF concentration <1μg/L was observed for 7–11 days with a significant increase in the mixing depth layer and turbidity. The results suggest that cyanobacterial blooms are robustly associated with thermal stratification and rainstorm floods in the deep and oligotrophic lake. Thermal stratification boosts surface phytoplankton accumulation by increasing water temperature, enhancing light availability and restricting phytoplankton vertical distribution. Rainstorm floods interrupt the accumulation by disrupting thermal stratification and decreasing the available light. Furthermore, wind speed and air temperature both regulate the phytoplankton dynamics by affecting thermal stratification. Our research quantifies the cyanobacterial bloom dynamics and their relationship between environmental factors, improving our knowledge of the driving mechanisms of cyanobacterial bloom for the protection of drinking water safety and aquatic organism health in lakes.