Chidimma Anthonia Azike^1,, Vivian Nkemkanma Agi¹, Ollor Amba Ollor¹, Easter Godwin Nwokah¹, Chinyere Ihuarulam Okoro², Confidence Kinikanwo Wachukwu¹

Background: This study aimed to determine the microbial diversity and Community Structure of Coastal water bodies from some cholera-prone communities in Rivers State. Methods: Water samples were collected from water bodies located in six different cholera prone coastal communities in Rivers state three times each with the determination of coordinates each time using Global Positioning System (GPS). At each collection point, in-situ physicochemical parameters of water sources were determined using H198194, H198195, and H198196 multiparameter meters (Hanna Instrument Inc, USA). The water samples were collected using a sterilized container of 750ml capacity (75cl). DNA was extracted from each water sample collected. The extracted DNA from the water samples were sequenced by Illumina HighSeq by InqabaBiotec, South Africa. The sequencing library was prepared by random fragmentation of the DNA, followed by 5′and 3′ adapter ligation. Adapter-ligated fragments were then PCR-amplified and gel purified. For cluster generation, the library was loaded into a flow cell where fragments were captured on a lawn of surface-bound oligos complementary to the library adapters. Each fragment was then amplified in to distinct, clonal clusters through bridge amplification. When cluster generation was complete, the templates were sequenced using Illumina MiSeq SBS technology. Results: The microbial communities in the coastal water studied are highly diversified. The microorganisms are generally classified into kingdoms containing bacteria, protozoa, viruses, archaea, fungi, and Plantae. For all the coastal waters, kingdom bacteria is common with varying percentage reads which ranged from 45835 reads (46.64%) in Bonny river to 263985 reads (99.71%) in Kaa river. Protozoa were identified in addition to other microbial communities in Andoni and Kaa rivers, both in the South-east senatorial district of Rivers State. The number of viruses detected is more in the Chukwu-Ama river in Ogu/bolo with total reads of 384 (0.25% of microbes present). In addition to other kingdoms present in the Okirika River, fungi were also detected. Alpha diversity of bacterial species across the three regions investigated showed no significant difference while that of individual samples was significantly different at P≤ 0.05 using observed features, Shannon diversity index, Faith’s phylogenetic diversity and Pielou’s evenness tools. Bray-Curtis dissimilarity between the bacterial communities’ structures in the three zones investigated did not reveal distinct differentiation in multivariate space. The observed clustering pattern of samples within the PCoA (Principal coordinate analysis) plot was found to be non-significantly (FDR-adjusted p>0.05) different among the zones in Rivers State (PERMANOVA R2 = 43.3%, p = 0.07). The ASVs detected in all zones of Rivers state spanned 15 phyla (Rivers East = 13; Rivers South-east = 13; Rivers West = 10). Actinobacteriota was the most relatively abundant phyla in both Rivers East (43.9%) and Rivers South-east (35.5%) while Firmicutes (36.2%) was the most abundant phyla in Rivers West. Conclusion: This study has shown that microbial communities present in coastal waters are highly diversified with unknown and unassigned microorganisms detected from all the coastal water examined, showing that these waters are hubs for highly potential microorganisms that could be inimical to human health.

microbial diversity, Microbial Structure, coastal water, cholera, community