Soil-microbial communities indexing from mangroves rhizosphere and barren sandy habitats

This work assessed the role of mangrove vegetation on soil characteristics of mangrove sediment and barren sandy soil in order to assess the impact of mangrove vegetation on the coastal soil. The soil samples were obtained from three sites (natural mangroves, planted mangroves, and non-mangrove sandy shore) located in the Vellar-coleroon estuarine complex for four seasons at three different soil depths (0-10, 10-50 and 50-100 cm). The samples were analyzed for microbial counts, nutrients and trace elements. The total fungal count was 42.5-fold higher in natural mangrove sediment than sandy soil as against the total heterotrophic bacterial count which was only 1.9-fold higher. Notably, planted mangrove sediment had higher total organic carbon, microbial carbon, N, P and K than the sandy soil. There was a significant correlation between soil temperature and microbial counts revealing that the temperature rise may be favorable for soil biospheres such as heterotrophs, saprophytes, and parasites. Remarkably, boron, cadmium, and cobalt were many folds greater in the natural mangrove sediments than that in planted mangrove sediment. This work has suggested that an amendment of sandy soil with nutrients nitrogen and microbial biomass is likely to transform the barren soil into carbon-rich mangroves.