The microbial world of sand

A trip to the beach offers countless recreational activities, from swimming and surfing to fishing and building sandcastles. For children, it’s also a chance to connect with nature. Beaches are edge ecosystems—places where land and sea meet—and their sands hide a remarkable diversity of microorganisms. These microbes live in habitats shaped by the amount and type of water filtering through the sand, and they play essential roles: they remove excess dissolved carbon and nitrogen from seawater and form the base of the food chain for small animals like shellfish and crustaceans. Larger animals feed on these, supporting activities such as fishing and birdwatching. Despite appearing stable, beaches are dynamic systems, continuously reshaped by storms and sea level rise, forcing their microbial and animal communities to adapt and rebalance.