Stratified sediments in the Black Sea, characterized by significant differences in hydrogen sulfide and oxygen levels, harbor distinct microbial communities as revealed by Oxford Nanopore sequencing

An analysis was conducted on the microbial communities present in sediments from the deep basin and shelf zones of the Black Sea. The purpose of the study was to demonstrate that these zones, characterized by reducing (hydrogen sulfide in the deep sea at a depth of 2030m, between 20 to 75 cm in depth) and oxidizing (oxygen-containing sea at 49m, between 20 to 70 cm in depth) conditions, are home to distinct microbial communities. DNA was extracted from different sediment layers and then PCR-amplified, followed by Oxford nanopore sequencing. The analysis discovered a total of 44 bacterial phylotypes, with 25 intrinsic to the shelf zone, eight specific to the deep sediment hydrogen sulfide zone, and 11 present in both zones. Additionally, archaea were found to be represented by six phyla and mainly inhabited the shelf 49m deep sediment. These findings indicate that the Black Sea's two zones indeed harbor unique microbial communities, and the study delves into the implications for potential biogeochemical cycles.