Affe Helen M de Jesus, Rigonato Janaina, Nunes José M de Castro, Menezes Mariângela
Laboratório de Algas Marinhas, Instituto de Biologia, Universidade Federal da Bahia, Salvador, Brazil.
Centro de Energia Nuclear e Agricultura, Universidade de São Paulo, Piracicaba, Brazil.
Front Microbiol. 2018 Jun 26;9:1393. doi: 10.3389/fmicb.2018.01393. eCollection 2018.
This study assessed the species composition, distribution, and functional profiles of cyanobacteria in Camamu Bay, a tropical oligotrophic estuarine system on the northeast coast of Brazil, using shotgun metagenomic sequencing. Surface-water samples were evaluated in two different rainfall periods (rainy and dry seasons), at nine stations in the three hydrodynamic regions of the bay. At a fixed sampling station, on each season, samples were taken over a tidal cycle at 3-h intervals over 12 h. A total of 219 cyanobacterial taxa were identified, demonstrating a diverse community of freshwater, euryhaline, and marine cyanobacteria. The genera of greater relative abundance, and , corresponded to the picoplankton fraction. Although Camamu Bay has conspicuous marine characteristics, the contribution of freshwater during the rainy season caused variation in cyanobacteria community, with an increase in species richness. Due the high prevalence of (90% of the sequences), the functional analysis revealed only minor differences in gene content between the dry and rainy seasons. In both rainy and dry seasons, an increase in relative abundance occurred during high tide, demonstrating the tidal influence in the bay. The environmental characteristics of the bay provide niche conditions for a wide variety of cyanobacteria, including freshwater, euryhaline, and marine strains.
本研究采用鸟枪法宏基因组测序技术，评估了巴西东北海岸热带贫营养河口系统卡马穆湾蓝藻的物种组成、分布和功能概况。在该湾三个水动力区域的九个站点，对两个不同降雨期（雨季和旱季）的地表水样本进行了评估。在固定采样站，每个季节在12小时内每隔3小时在一个潮汐周期内采集样本。共鉴定出219种蓝藻分类群，表明存在淡水、广盐性和海洋蓝藻的多样化群落。相对丰度较高的属 和 ，对应于微微型浮游生物部分。尽管卡马穆湾具有明显的海洋特征，但雨季淡水的贡献导致蓝藻群落发生变化，物种丰富度增加。由于 （序列的90%）的高流行率，功能分析显示旱季和雨季之间基因含量仅有微小差异。在雨季和旱季，涨潮期间 相对丰度均增加，表明该湾受潮汐影响。该湾的环境特征为包括淡水、广盐性和海洋菌株在内的多种蓝藻提供了生态位条件。
