Metagenomic insights on soil microbiome biodiversity from an eroding coastline of Tanjung Piai, Johor State Park, Malaysia

Abstract

The Tanjung Piai National Park is an important tourist attraction and has been severely affected by erosion and pollution, threatening its soil biodiversity. Microbes in mangroves control various nutrient transformation processes in the ecosystem and their population differ with regards to spatial variation. In our current efforts to elucidate the relationship between soil variables and bacterial population, we analysed high-throughput metagenomic datasets from two sites of an old growth mangrove and a severely eroded intertidal mudflat in Tanjung Piai National Park. Sediment samples were collected at 5–20 cm depth for analysis. Bacterial communities were investigated by throughput sequencing of the 16S rRNA gene. Soil pH, organic carbon, organic matter and nitrogen content significantly differed at both sites. Bacterial community structure revealed that sediments from both sites were dominated by phylum Proteobacteria (32–58%), followed by Chloroflexi (6–19%) and Bacteroidetes (2–5%). Intertidal mudflats had the highest numbers of operational taxonomic unit, as well as Proteobacteria (47%), Firmicutes (1%) and Spriochaetes (4%) compared with the old growth forest, which recorded the highest Bathyarchaeota (11%) population. Results revealed the sustenance of observed phylum in the soils of contrasting sites and call for future strategies in elucidating functional analysis of bacterial population in further understanding their roles in mangrove ecosystems.