Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, South Donghu Road 7, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100039, China.
Affiliated Stomatology Hospital of Guangzhou Medical University, Guangzhou 510182, China.
Harmful Algae. 2020 Jul;97:101858. doi: 10.1016/j.hal.2020.101858. Epub 2020 Jun 24.
As a successful invasive cyanobacterial species, Raphidiopsis raciborskii is distributed globally and shows a tendency to replace Microcystis aeruginosa in many subtropical and temperate waters, but the ecological traits that contribute to its invasiveness are still unclear. In this study, we found that R. raciborskii occurred in 149 sites in 42 lakes in eastern and central China and coexisted with M. aeruginosa at most sites. Based on field results, a combination of invasion and competition experiments using a biomass gradient to evaluate the invasiveness and competitiveness of R. raciborskii compared with M. aeruginosa was conducted. In invasive groups, both R. raciborskii and M. aeruginosa were shown to have positive specific growth rates, indicating that R. raciborskii could coexist with M. aeruginosa. Furthermore, R. raciborskii was shown to grow faster from invasion while M. aeruginosa reduced growth for invasion. In competitive groups, R. raciborskii reached a higher maximum biomass and grew longer than M. aeruginosa. The specific growth rate of R. raciborskii was not inhibited by M. aeruginosa biomass, whereas the growth of M. aeruginosa was inhibited by R. raciborskii biomass. It was shown during the whole experiment that R. raciborskii tended to replace M. aeruginosa to become dominant owing to its faster growth rate and the eventual decline in growth of M. aeruginosa. With an increase in biomass of M. aeruginosa, the vegetative cell size and filament length of R. raciborskii gradually increased. This study has demonstrated that the inherent invasive traits of R. raciborskii, size differences, niche differences, and relative fitness differences between R. raciborskii and M. aeruginosa are crucial reasons for the invasive success of R. raciborskii. Our results revealed the invasiveness and domination of R. raciborskii from a new perspective.
作为一种成功的入侵性蓝藻物种，Raphidiopsis raciborskii 分布于全球，并且在许多亚热带和温带水域中呈现出取代 Microcystis aeruginosa 的趋势，但导致其入侵性的生态特征仍不清楚。在这项研究中，我们发现 R. raciborskii 存在于中国东部和中部的 42 个湖泊的 149 个地点，并且在大多数地点与 M. aeruginosa 共存。基于野外结果，我们进行了使用生物量梯度的入侵和竞争实验的组合，以评估 R. raciborskii 与 M. aeruginosa 的入侵性和竞争力。在入侵组中，R. raciborskii 和 M. aeruginosa 的特定生长率均为正，表明 R. raciborskii 可以与 M. aeruginosa 共存。此外，R. raciborskii 在入侵时生长更快，而 M. aeruginosa 在入侵时生长减慢。在竞争组中，R. raciborskii 达到的最大生物量更高，生长时间更长。R. raciborskii 的特定生长率不受 M. aeruginosa 生物量的抑制，而 M. aeruginosa 的生长受到 R. raciborskii 生物量的抑制。整个实验表明，由于 R. raciborskii 的生长速度更快，并且 M. aeruginosa 的生长最终下降，R. raciborskii 倾向于取代 M. aeruginosa 成为优势种。随着 M. aeruginosa 生物量的增加，R. raciborskii 的营养细胞大小和藻丝长度逐渐增加。这项研究表明，R. raciborskii 的固有入侵特性、大小差异、生态位差异以及与 M. aeruginosa 的相对适合度差异是 R. raciborskii 成功入侵的关键原因。我们的研究结果从新的角度揭示了 R. raciborskii 的入侵性和优势性。
