Not all creatures in the Baltic Sea are mobile. Sea anemones, sponges and even mussels live sessile on rocks and boulders. The interplay of currents and waves invites inertia. The constant flow of water brings nutrients to almost every part of this marine environment, creating richly structured seabed habitats – the Baltic Reefs. As oases of biodiversity these are a home for various species – each with its own ecological niche, its own cave and its own hiding place.