Investigating Abiotic Drivers for Vertical and Temporal Heterogeneities of Cyanobacteria Concentrations in Lakes Using a Seasonal In Situ Monitoring Station
Investigating Abiotic Drivers for Vertical and Temporal Heterogeneities of Cyanobacteria Concentrations in Lakes Using a Seasonal In Situ Monitoring Station
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DOI：
10.1029/2018wr024228
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发表时间：
2019-02
影响因子：
5.4
通讯作者：
A. Wilkinson;M. Hondzo;M. Guala
中科院分区：
文献类型：
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作者：
A. Wilkinson;M. Hondzo;M. Guala
有害藻华（HAB）是普遍存在的生态和公共健康危害，因为它们是由潜在有毒的淡水微生物蓝藻组成的。2016年，利用部署在明尼苏达州富营养化湖泊的研究站，研究了有毒有害藻华的非生物驱动因素。该研究站在采样点提供全深度水质（每小时）和气象条件监测（5分钟）。水质监测提供了化学、物理和生物测量，即藻蓝蛋白浓度，一种与蓝藻细菌不同的光合色素。7月中旬观察到的尾海蓝藻高生物量（BV）一直持续到9月下旬，并在整个水柱中均匀分布。BV非均质性、热分层稳定性与地表水温度之间存在标度关系。这种关系在第二年的一个双晶湖泊中得到了证实。所提出的标度关系与有害藻华的采样方案有关，因为它可以告知样本深度是否代表整个水柱。在强分层期，BV在温跃层上方和光区积累，在水面附近和光合有效辐射约为10 μE/m2s的位置偶尔形成明显的峰值。研究结果表明，蓝藻BV的时间/垂直变化受到湖泊动态、热结构、季节温度变化和光照有效性的强烈影响。这些观察结果表明，蓝藻倾向于在特定的暖水层中移动和积累，受温跃层的限制，并由明确的光照条件决定。
Harmful algal blooms (HAB) are ubiquitous ecological and public health hazards because they are composed of potentially toxic freshwater microorganisms called cyanobacteria. The abiotic drivers for toxic HAB are investigated using a research station deployed in a eutrophic lake in Minnesota in 2016. This research station provides full‐depth water quality (hourly) and meteorological conditions monitoring (5 min) at the sampling site. Water quality monitoring provides chemical, physical, and biological measurements, that is, phycocyanin concentration, a photosynthetic pigment distinct to cyanobacteria. The high cyanobacteria biovolume (BV) in the epilimnion observed in mid‐July persisted until late September when it was distributed uniformly throughout the water column. A scaling relationship was developed among BV heterogeneity, thermal stratification stability, and surface water temperature. This relationship was verified in a dimictic lake the following year. The proposed scaling relationship is relevant to sampling protocols of HAB as it informs if the sample depth is representative of the entire water column. During the strongly stratified period, BV accumulated above the thermocline and in the photic zone, with distinct peaks forming occasionally both near the water surface and at locations with photosynthetically active radiation approximately equal to 10 μE/m2s. Our observations suggest that the temporal/vertical variability of cyanobacteria BV is strongly influenced by lake dynamics, thermal structure, seasonal temperature variation, and light availability. These observations demonstrate that cyanobacteria tend to move and accumulate in specific warm water layers, confined by the thermocline and determined by well‐defined light conditions.