Elucidating the Influences of Environmental Pollution on Microbial Ecosystems and Biotransformation Functions in Pearl River Estuary Sediments in Dry and Wet Seasons

The region around the Pearl River Estuary (PRE) in southern China has a population of approximately 65 million and contributes ~10% of the country’s GDP. However, the rapid industrialization and development of densely populated coastal cities inevitably has contributed to the introduction of various legacy pollutants and contaminants of emerging concern into nearby aquatic environments. As pollutants accumulate in PRE sediments, they disrupt ecosystem functions, harm aquatic life, and threaten human health. These sediments contain diverse microbial populations that play an important role in biogeochemical processes and may offer an effective and low-cost strategy for the removal of pollutants, thereby reducing the environmental impact and enhancing the sustainability of future economic development in the PRE region. Thus far, a comprehensive assessment of the PRE sediment microbial community or microbiome is lacking. In particular, the spatial and seasonal compositions of the microbiome (i.e., the active microbial members) and how biotransformation influences the fate of pollutants in the PRE sediments remain poorly understood. Given the importance of the sediment microbiome to local and global biogeochemical processes and the ever-increasing load of anthropogenic pollutants in PRE sediments, a comprehensive study is essential to fill these critical knowledge gaps. We thus propose to comprehensively describe thein situmicrobiome in PRE sediments over a wide spatial area in both dry and wet seasons by compiling data collected using state-of-the-art metagenomics, metatranscriptomics, and metaproteomics approaches. The environmental conditions and the concentrations of two specific groups of pollutants, including antibiotics (which can lead to antibiotic-resistance in bacteria) and per- and polyfluoroalkyl substances (contaminants of emerging concern), in the sediments will be measured and correlated with the multi-omics data to understand their relationships. To complement the field study, laboratory microcosm experiments will be conducted to test how environmental pollutants change microbiome structures and to identify functionally important microbes. We hypothesize that the environmental conditions and levels of pollution will be associated with changes in the taxonomic composition and metabolic functions in the sediment microbiome, as supported by our preliminary metagenomic results of the PRE sediments. Overall, the insights derived from our field study and laboratory microcosms will advance scientific knowledge regarding the microbiology and environmental sciences of PRE sediments, which will subsequently lead to tangible positive outcomes when practitioners develop knowledge-driven control measures to improve the environmental quality of the PRE region.