Bagatini Inessa Lacativa, Eiler Alexander, Bertilsson Stefan, Klaveness Dag, Tessarolli Letícia Piton, Vieira Armando Augusto Henriques
Laboratório de Ficologia, Departamento de Botânica, Universidade Federal de São Carlos, São Carlos, SP, Brasil.
Department of Ecology and Genetics, Limnology and Science for Life Laboratories, Uppsala University, Uppsala, Sweden.
PLoS One. 2014 Jan 20;9(1):e85950. doi: 10.1371/journal.pone.0085950. eCollection 2014.
Many freshwater phytoplankton species have the potential to form transient nuisance blooms that affect water quality and other aquatic biota. Heterotrophic bacteria can influence such blooms via nutrient regeneration but also via antagonism and other biotic interactions. We studied the composition of bacterial communities associated with three bloom-forming freshwater phytoplankton species, the diatom Aulacoseira granulata and the cyanobacteria Microcystis aeruginosa and Cylindrospermopsis raciborskii. Experimental cultures incubated with and without lake bacteria were sampled in three different growth phases and bacterial community composition was assessed by 454-Pyrosequencing of 16S rRNA gene amplicons. Betaproteobacteria were dominant in all cultures inoculated with lake bacteria, but decreased during the experiment. In contrast, Alphaproteobacteria, which made up the second most abundant class of bacteria, increased overall during the course of the experiment. Other bacterial classes responded in contrasting ways to the experimental incubations causing significantly different bacterial communities to develop in response to host phytoplankton species, growth phase and between attached and free-living fractions. Differences in bacterial community composition between cyanobacteria and diatom cultures were greater than between the two cyanobacteria. Despite the significance, major differences between phytoplankton cultures were in the proportion of the OTUs rather than in the absence or presence of specific taxa. Different phytoplankton species favoring different bacterial communities may have important consequences for the fate of organic matter in systems where these bloom forming species occur. The dynamics and development of transient blooms may also be affected as bacterial communities seem to influence phytoplankton species growth in contrasting ways.
许多淡水浮游植物物种有可能形成短暂的有害水华，影响水质和其他水生生物群。异养细菌可通过养分再生影响此类水华，也可通过拮抗作用和其他生物相互作用产生影响。我们研究了与三种形成水华的淡水浮游植物物种相关的细菌群落组成，即硅藻颗粒直链藻以及蓝藻铜绿微囊藻和拉氏柱孢藻。在三个不同生长阶段对添加和不添加湖泊细菌的实验培养物进行采样，并通过对16S rRNA基因扩增子进行454焦磷酸测序来评估细菌群落组成。β-变形菌纲在所有接种湖泊细菌的培养物中占主导地位，但在实验过程中减少。相比之下，作为第二丰富细菌类别的α-变形菌纲在实验过程中总体上有所增加。其他细菌类别对实验培养的反应方式不同，导致因宿主浮游植物物种、生长阶段以及附着和自由生活部分的不同而形成显著不同的细菌群落。蓝藻和硅藻培养物之间的细菌群落组成差异大于两种蓝藻之间的差异。尽管差异显著，但浮游植物培养物之间的主要差异在于操作分类单元的比例，而非特定分类群的有无。在这些形成水华的物种出现的系统中，不同的浮游植物物种偏好不同的细菌群落可能会对有机物的命运产生重要影响。由于细菌群落似乎以不同方式影响浮游植物物种的生长，短暂水华的动态和发展也可能受到影响。
