Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China.
Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Nanjing, 210098, China.
Harmful Algae. 2019 Nov;89:101661. doi: 10.1016/j.hal.2019.101661. Epub 2019 Oct 8.
Micro-cyanobacteria and pico-cyanobacteria coexist in many lakes throughout the world. Their distinct cell sizes and nutrient utilization strategies may lead to dominance of one over the other at varying nutrient levels. In this study, Microcystis aeruginosa and Synechococcus sp. were chosen as representative organisms of micro- and pico-cyanobacteria, respectively. A series of nitrate and ammonia conditions (0.02, 0.1, 0.5, and 2.5 mg N L) were designed in mono- or co-cultured systems, respectively. Growth rates of the two species were calculated and fitted by the Monod and Logistic equations. Furthermore, the interspecific competition was analyzed using the Lotka-Volterra model. In mono-cultures, the two cyanobacteria displayed faster growth rates in ammonia than in nitrate. Meanwhile, Synechococcus sp. showed faster growth rates compared to M. aeruginosa in lower N groups (≤ 0.5 mg N L). However, in the highest nitrate treatment (2.5 mg N L), M. aeruginosa achieved much higher biomass and faster growth rates than Synechococcus sp.. In co-cultures, Synechococcus sp. dominated in the lowest N treatment (0.02 mg N L), but M. aeruginosa dominated under the highest nitrate condition (2.5 mg N L). Based on the analysis of Raman spectra of living cells in mono-cultures, nitrate (2.5 mg N L) upgraded the pigmentary contents of M. aeruginosa better than ammonia (2.5 mg N L), but nitrogen in different forms showed little effects on the pigments of Synechococcus sp.. Findings from this study can provide valuable information to predict cyanobacterial community succession and aquatic ecosystem stability.
微囊藻和微微囊藻在世界上许多湖泊中共存。它们不同的细胞大小和养分利用策略可能导致在不同养分水平下，一种藻超过另一种藻而成为优势种。在这项研究中，选择铜绿微囊藻和聚球藻分别作为微囊藻和微微囊藻的代表生物。分别在单培养和共培养系统中设计了一系列硝酸盐和氨条件（0.02、0.1、0.5 和 2.5mgNL）。通过 Monod 和 Logistic 方程计算并拟合了两种生物的生长率。此外，使用 Lotka-Volterra 模型分析了种间竞争。在单培养中，两种蓝藻在氨中比在硝酸盐中的生长速度更快。同时，在较低氮组（≤0.5mgNL）中，聚球藻的生长速度比铜绿微囊藻快。然而，在最高硝酸盐处理（2.5mgNL）中，铜绿微囊藻的生物量和生长速度均高于聚球藻。在共培养中，聚球藻在最低氮处理（0.02mgNL）中占主导地位，但在最高硝酸盐条件（2.5mgNL）下，铜绿微囊藻占主导地位。基于单培养中活细胞的拉曼光谱分析，硝酸盐（2.5mgNL）比氨（2.5mgNL）更能提高铜绿微囊藻的色素含量，但不同形式的氮对聚球藻的色素几乎没有影响。本研究的结果可为预测蓝藻群落演替和水生生态系统稳定性提供有价值的信息。
