Sedimentary Rocks as Analogues of Coastal Pollution and Sustainable Solutions Building Future Resilience

Coastal marine ecosystems occur at the land-sea interface and are under severe threat from pollution, species loss, and climate change. Beachrock, a coastal sedimentary rock formed through rapid carbonate cementation, develops in the intertidal zone where land-sea interactions are highly dynamic. In this review, we propose that beachrock not only serves as a potential Anthropocene record of coastal pollution but may also function as a Nature-based Solution (NbS) by building coastal ecosystem resilience. First, elevated concentrations of metal(loid)s in intertidal beachrock were identified, and underlying mechanisms were further assessed. Second, the potential use of beachrock in environmental forensics was examined by analyzing diagnostic compositions of typical organic pollutants. Furthermore, novel plastic forms were discovered when plastic lithifies with beachrock, creating an evidence-based marker of the Anthropocene and signifying the incorporation of synthetic materials into Earth's geological record. Finally, we propose that beachrock formation can be artificially induced through microbially induced carbonate precipitation, offering a restorative alternative to traditional cementitious materials, supporting coastal engineering innovation-based solutions that provide multiple benefits. By integrating perspectives from environmental science, climate science, materials science, earth science, and microbiology, we highlight beachrock's potential regarding innovative applications including coastal pollution monitoring, climate adaptation, and sustainable material development.