Flexi Says: Tide pool ecosystems are underwater in high tide and at least partly uncovered during low tide. An abundance of life is found there, but it's a difficult place to live. Conditions change rapidly. Waves pound and the tide goes in and out. Algae (seaweed) are the main producers. Primary consumers (herbivores) include periwinkle snails, sea urchins, and sea stars. Secondary and higher consumers (carnivores) include sculpins and sea otters. Omnivores include crabs and bat stars.