A rhizome with long green leaves attached left stranded on a beach after a winter storm shows that just offshore are undersea fields of common eelgrass, Zostera marina. Remarkably, eelgrass is a plant, not algae like seaweed.
The plants grow in sunlit shallow water producing seeds like terrestrial grass and using photosynthesis to grow. Their rhizome root system spreads under the sand, as a second reproduction method, and in doing so stabilises the seabed, although their shallow habitat makes plants vulnerable to being uprooted by storms. Though the floating rhizome has the potential to begin a colony elsewhere.
