Ecomare

Plants need sunlight to produce energy. Therefore, they can only grow on the sea floor if sufficient sunlight can penetrate. A layer of diatoms, also referred to as a diatom mat, grows on soft, silty bottoms. Various kinds of larger seaweed species attach their foot to hard substrates, not to extract any nutrients, but to give them a foothold. Eelgrass is a higher order plant, producing seeds just like land plants. It is the only higher order plant that grows on the bottom of the coastal waters of the North Sea.