Woodhouse Jason Nicholas, Kinsela Andrew Stephen, Collins Richard Nicholas, Bowling Lee Chester, Honeyman Gordon L, Holliday Jon K, Neilan Brett Anthony
School of Biotechnology and Biomolecular Sciences, UNSW Australia, Sydney, New South Wales, Australia.
UNSW Water Research Centre and School of Civil and Environmental Engineering, UNSW Australia, Sydney, New South Wales, Australia.
ISME J. 2016 Jun;10(6):1337-51. doi: 10.1038/ismej.2015.218. Epub 2015 Dec 4.
The frequency of freshwater cyanobacterial blooms is at risk of increasing as a consequence of climate change and eutrophication of waterways. It is increasingly apparent that abiotic data are insufficient to explain variability within the cyanobacterial community, with biotic factors such as heterotrophic bacterioplankton, viruses and protists emerging as critical drivers. During the Australian summer of 2012-2013, a bloom that occurred in a shallow ephemeral lake over a 6-month period was comprised of 22 distinct cyanobacteria, including Microcystis, Dolichospermum, Oscillatoria and Sphaerospermopsis. Cyanobacterial cell densities, bacterial community composition and abiotic parameters were assessed over this period. Alpha-diversity indices and multivariate analysis were successful at differentiating three distinct bloom phases and the contribution of abiotic parameters to each. Network analysis, assessing correlations between biotic and abiotic variables, reproduced these phases and assessed the relative importance of both abiotic and biotic factors. Variables possessing elevated betweeness centrality included temperature, sodium and operational taxonomic units belonging to the phyla Verrucomicrobia, Planctomyces, Bacteroidetes and Actinobacteria. Species-specific associations between cyanobacteria and bacterioplankton, including the free-living Actinobacteria acI, Bacteroidetes, Betaproteobacteria and Verrucomicrobia, were also identified. We concluded that changes in the abundance and nature of freshwater cyanobacteria are associated with changes in the diversity and composition of lake bacterioplankton. Given this, an increase in the frequency of cyanobacteria blooms has the potential to alter nutrient cycling and contribute to long-term functional perturbation of freshwater systems.
由于气候变化和水道富营养化，淡水蓝藻水华的发生频率有增加的风险。越来越明显的是，非生物数据不足以解释蓝藻群落内部的变异性，而异养浮游细菌、病毒和原生生物等生物因素已成为关键驱动因素。在2012 - 2013年澳大利亚夏季，一个浅的季节性湖泊在6个月内发生的一次水华由22种不同的蓝藻组成，包括微囊藻、鱼腥藻、颤藻和球孢藻。在此期间评估了蓝藻细胞密度、细菌群落组成和非生物参数。α多样性指数和多变量分析成功区分了三个不同的水华阶段以及非生物参数对每个阶段的贡献。网络分析评估了生物和非生物变量之间的相关性，重现了这些阶段并评估了非生物和生物因素的相对重要性。具有较高介数中心性的变量包括温度、钠以及属于疣微菌门、浮霉菌门、拟杆菌门和放线菌门的操作分类单元。还确定了蓝藻与浮游细菌之间的物种特异性关联，包括自由生活的放线菌acI、拟杆菌、β-变形菌和疣微菌。我们得出结论，淡水蓝藻的丰度和性质变化与湖泊浮游细菌的多样性和组成变化有关。鉴于此，蓝藻水华频率的增加有可能改变养分循环并导致淡水系统的长期功能扰动。
