Roles of dilution rate and nitrogen concentration in competition between the cyanobacterium Microcystis aeruginosa and the diatom Cyclotella sp. in eutrophic lakes
Roles of dilution rate and nitrogen concentration in competition between the cyanobacterium Microcystis aeruginosa and the diatom Cyclotella sp. in eutrophic lakes
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DOI：
10.1007/s10811-015-0754-7
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发表时间：
2016-08
影响因子：
3.3
通讯作者：
K. Sugimoto;Yusuke Negishi;Y. Amano;M. Machida;F. Imazeki
中科院分区：
文献类型：
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作者：
K. Sugimoto;Yusuke Negishi;Y. Amano;M. Machida;F. Imazeki
在日本太贺湖，由于邻近河流的水排入湖中，导致优势藻类物种的转移。从蓝藻（主要是微囊藻属）到硅藻（主要是小环藻属）的转变导致了藻华的消失。虽然该项目改变了一些环境条件，如流速，营养物浓度和透明度，但尚未明确过渡的决定性因素。为有效控制水体水华，研究了水体更新速率和氮浓度对铜绿微囊藻（Microcystis aerodynosaA）和圆鳃藻（Cyclotellasp）种间竞争的影响。进行了单一培养实验以获得每个物种的生长特性，并进行了混合培养实验以检查它们在培养基的不同每日更新率（15%和30%）和硝酸盐浓度（71.4、178和357 μM）下的竞争能力。除制备的培养基外，还将Lake Tega水用于混合培养实验。结果表明，日更新率的增加有助于圆鳃金龟的优势度，而硝酸盐浓度对竞争影响不大。我们得出结论，在硝酸盐浓度≤357 μM的条件下，通过维持每日更新率高达30%或更高，相当于0.36天-1的稀释率，可以控制微囊藻属的水华。这项研究将包括管理频繁发生藻华的湖泊的基本资料。
In Lake Tega, Japan, the shift of dominant algal species was caused as a result of discharging water from the adjacent river into the lake. The transition from cyanobacteria (mainly the genusMicrocystis) to diatoms (mainly the genusCyclotella) resulted in a disappearance of algal blooms. Although some environmental conditions such as flow rate, nutrient concentration, and transparency were changed by the project, the decisive factor for the transition has not been clarified yet. For the effective control of algal blooms by water discharge, this study aimed to elucidate the effects of daily renewal rate and nitrogen concentration on the interspecific competition betweenMicrocystis aeruginosaandCyclotellasp. Monoculture experiments were conducted to obtain growth characteristics for each species and mixed culture experiments were performed to examine their competitive abilities under various daily renewal rates of the culture medium (15 and 30 %) and nitrate concentrations (71.4, 178, and 357 μM). In addition to prepared medium, Lake Tega water was also used for mixed culture experiments. The results showed that the increase in a daily renewal rate contributed to the dominance ofCyclotellasp., while a nitrate concentration had little influence on the competition. We conclude that algal blooms composed of the genusMicrocystiswould be controlled by maintaining a daily renewal rate up to 30 % or more, which corresponded to the dilution rate of 0.36 day−1, under a nitrate concentration of ≤357 μM. The study would include essential information for the management of lakes suffering from frequent occurrences of algal blooms.