Cyanobacteria are a group of diverse prokaryotes that are capable of oxygenic photosynthesis. They are ubiquitous in nature and have been reported to survive in extreme environments. This study aimed to identify and assess the diversity of the cyanobacteria present in some mine tailing sites in the towns of Itogon and Tuba, in Benguet Province, Philippines using isolation-dependent and isolation-independent methods. Analysis of the water and sediment samples from the mine tailing sites (designated as Acu, Ampu, TSF1 and TSF3) showed higher metal concentrations in the sediment samples (2930–11,500 mg/kg dry weight Ca, 10–34 mg/kg dry weight Cr, 83–6500 mg/kg dry weight Cu, 6–172 mg/kg dry weight Pb, 8310–32,600 mg/kg dry weight Mg, 640–3400 mg/kg dry weight K, 43–144 mg/kg dry weight Zn), which were then processed for cyanobacterial enrichment. Identification of cyanobacteria was performed using the conventional isolation-dependent method for the characterization of microorganisms, 16S rRNA gene sequencing, and isolation-independent 16S rRNA metabarcoding analysis. Both approaches revealed that Arthronema africanum (1.98–60.1%) and Leptolyngbya spp. (39.9–97.0%) of the Pseudoanabaenales dominated the cyanobacterial composition in all sites. The isolation-dependent method identified most of the dominant taxa such as Arthronema africanum, Leptolyngbya spp. and Calothrix spp. Nodosilinea spp. was also confirmed to be part of the cyanobacterial community through this method. Unicellular cyanobacteria such as Chroococcales and Synechococcales were also observed. However, they were not fully identified at lower taxonomic levels in both methods, especially Chroococcales. On the other hand, the isolation-independent method recovered other taxa in selected sites such as Calothrix (0.002–0.022%), Halomicronema (0.01%), Nostoc (0.006–0.03%), Phormidium (0.007–14.1%), Planktothrix (0.36%), Pseudoanabaena (0.02–0.6%), Acaryochloris (0.006%), and Thermosynechococcus (0.02–4.7%). Metabarcoding revealed that samples from small-scale mine tailing ponds of Acu and Ampu, and the inactive pond of the large scale mining site, TSF1, had higher species diversity and evenness as compared to its active pond, TSF3, based on Shannon and Simpson indices. However, TSF1 and TSF3 of the large-scale mine tailings had higher species richness than Acu and Ampu of small-scale mining based on Chao index. Altogether, this study provided an inventory of cyanobacteria that can survive even in extreme metal conditions giving insights to their future applications, particularly, in bioremediation.

蓝细菌是一组能够进行光合作用的原核生物。它们本质上无处不在，据报道可以在极端环境中生存。这项研究旨在使用隔离依赖和隔离无关的方法，鉴定和评估菲律宾本格特省伊托贡和图巴镇某些矿山尾矿场中存在的蓝细菌的多样性。对来自矿山尾矿场（分别称为Acu，Ampu，TSF1和TSF3）的水和沉积物样品的分析显示，沉积物样品中的金属浓度较高（2930–11,500 mg / kg干重Ca，10–34 mg / kg干重Cr，83–6500 mg / kg干重Cu，6–172 mg / kg干重Pb，8310–32,600 mg / kg干重Mg，640–3400 mg / kg干重K，43–144 mg / kg干重Zn），然后进行处理以进行蓝细菌富集。使用常规的依赖于分离的方法表征细菌，进行16S rRNA基因测序和不依赖于分离的16S rRNA元条形码分析，从而进行了蓝藻细菌的鉴定。两种方法都表明非洲节肢动物（1.98–60.1％）和钩端螺旋体。（39.9–97.0％）的拟南芥在所有部位中均占主导地位。依赖隔离的方法可以识别大多数优势类群，例如非洲节肢动物，钩端螺旋体。和Calothrix spp。Nodosilinea spp。通过这种方法也被证实是蓝细菌群落的一部分。还观察到单细胞蓝细菌，例如球菌和突触球菌。但是，在两种方法中，特别是在绿球菌中，都没有在较低的分类学水平上完全鉴定出它们。另一方面，与隔离无关的方法可以在选定的地点（例如Calothrix）中恢复其他类群（0.002-0.022％），Halomicronema（0.01％），发菜（0.006-0.03％），席藻（0.007-14.1％），Planktothrix（0.36％），Pseudoanabaena（0.02-0.6％），Acaryochloris（0.006％），和嗜热球菌（0.02–4.7％）。元条形码显示，基于香农和辛普森指数，与其活动池TSF3相比，来自Acu和Ampu的小型矿山尾矿池以及大型采矿场所的非活动池TSF1的物种多样性和均匀度更高。 。但是，大型矿山尾矿的TSF1和TSF3的物种丰富度高于基于Chao指数的小型矿山的Acu和Ampu。总而言之，这项研究提供了即使在极端金属条件下也能生存的蓝细菌清单，从而为它们的未来应用提供了见识，尤其是在生物修复方面。