Dip your head below the water's surface in a mangrove forest and an entirely new ecosystem is revealed. The twisting mangrove roots, some of which don’t make it to the seafloor, support a great diversity of life—including sponges, sea anemones, brittle stars, and sea urchins. The roots also serve as a nursery area for fishes and other organisms: the dense roots provide hiding places for young fish, and the roots and organisms living upon them provide nutrients and particulate food.