Abstract: Since the discovery of cable bacteria in sediments in 2012, they have attracted considerable attention for their remarkable capacity in mediating centimeter-scale long-distance electron transport. They are globally distributed in marine and freshwater. Their survival depends on the access to electron donors (sulfides) and acceptors (oxygen), and their species composition and diversity is determined by salinity. Cable bacteria can bridge oxic and sulfidic zones, functioning as biological conductors through electrogenic sulfur oxidation (e-SOx) to spatially separate oxidation and reduction reactions, create suboxic zones, and drive the biogeochemical cycling of key elements, including sulfur, iron, calcium, manganese, nitrogen, and phosphorus. In the restoration of aquatic ecosystems, cable bacteria show considerable potential to alleviate hypoxia and eutrophication, degrade toxic and hazardous pollutants, facilitate heavy metal removal, mitigate greenhouse gas emissions, and improve the rhizosphere conditions of aquatic plants. They can also be coupled with other technologies such as microbial electrochemical snorkels, microbial fuel cells, and aeration, to enhance restoration efficiency. In this review, we systematically summarized the distribution of cable bacteria in aquatic ecosystems and the major environmental factors affecting their survival and composition, analyzed the fundamental role of cable bacteria in the biogeochemical cycling of key elements in sediments, and discussed the exploration of cable bacteria in pollution control and aquatic ecosystem remediation. We highlighted the key discoveries, opportunities, and challenges of their role in aquatic environment remediation, and proposed a constructive outlook.

Key words: cable bacteria, electrogenic sulfur oxidation, water pollution control, biogeochemical cycling, water environment restoration