Ocean environments change with depth and distance from shore. • Near shore environments are called the neritic zone – water above the continental shelf • sunlight still reaches this area • Nutrients are still washed in from the land • Supports the most types of life than anywhere else on Earth • Life: plants (as tall as 10 story buildings) and animals (larger than elephants). These are all part of the food web
The waters near the shore support diverse life forms. • Coral Reefs: built-up limestone deposits formed by large colonies of ant-sized organisms called corals • In warm, tropical regions • Corals are small animals that produce hard structures that surround their bodies • When a coral dies, the structure remains and new coral attach to the structure • Australia’s Great Barrier Reef is about 1250 miles long • Eat a specific type of algae. The algae grows inside of the coral. It produces food that gives coral nutrition. The algae needs sunlight to survive so coral can only exist near shore. • Corals contain about 25% of all the species of ocean life. Animals use this for protection and food. • Corals are endangered. Pollution and fishing really harm the corals. • An atoll is a ring shaped reef surrounding a shallow lagoon • Kelp Forests: large communities of seaweed called kelp that attaches itself to the ocean floor and grows as tall as 130 feet. These have air filled bulbs that help the plant grow up towards the sun. • In cold waters but uses sunlight to produce food so it only grows near shore • Animals like lobsters, crabs, octopuses, and sea otters find shelter and food here
Environments in the open ocean change with depth. • Surface Zone – the top 650 feet • Microscopic floating organisms called phytoplankton live at or near the surface and convert sunlight and carbon dioxide into food and oxygen. They convert as much carbon dioxide as all land plants combined. Zooplankton eats the phytoplankton. Fish eat the zooplankton. • To keep from sinking, phytoplankton uses air bubbles. Many fish have this same ability in an air bladder. Changing the amount of air allows them to move up and down. • Deep Zone • Under the surface zone • No sunlight = no plants • Animals rely on eating each other or food drifting down from above • Animals in deep water have small eyes or no eyes at all
New discoveries about ocean life continue. • Hydrothermal vents – openings in the Earth’s crust. These heat cold water that seeps into cracks by the hot magma. The warm water rises and gushes back out into the ocean. • Scientists discovered in 1977 that animals create communities that thrive around these (crabs, shrimp, tubeworms). Before, they did not think life on the deep ocean floor was possible. • These animals depend on a certain type of bacteria and chemicals that comes from inside the earth. Rather than sunlight, these plants are making food from the chemicals released. Bacteria is the bottom of the food chain in these areas. Animals eat this bacteria. Tubeworms do not eat, but instead, absorb the food. • The deep ocean still remains mostly unexplored due to pressure, darkness and size.