Seagrass ecosystems as green urban infrastructure to reduce human pathogens in food from the sea. Microbiota of Mussels

Urban greening of coastal environments offers a strategic opportunity to reinforce the security and safety of food from the sea. Seagrass ecosystems can reduce human bacterial pathogens from terrestrial sources, however it remains unknown whether this health benefit is conferred to associated food fish. Marine bivalves are effective bioindicators of bacterial contamination and constitute over half of global seafood production. Following a three month deployment across 20 coastal urban locations in the greater Seattle Metropolitan Area, we find that bivalves retrieved from locations with seagrass present had a 65% reduction in the abundance of bacterial species with known human pathogenicity when compared to locations without seagrass. Our global models estimate that 1.1 billion people currently reside in over one-third (662 of 1,860) of urban agglomerations (populations over 300,000 people) and 19 megacities (populations over 10 million people) within 50 km of seagrass ecosystems, which we forecast to rise 15% by 2030 to include 1.3 billion people and 24 megacities. Given increasing reliance on food from the sea to meet supply and nutritional needs, these results highlight the global applicability of extending urban greening concepts from terrestrial to marine environments to support ambitious human health and biodiversity sustainability targets.