This lesson covers the food web and ecosystem of coral reefs. We’ll learn what a food web is and what coral reefs are and also take a look at a couple of specific examples of coral reef food webs.
An Underwater World
Beautiful beaches abound in the tropics. Luxurious hotels dot the shoreline with chairs, cabanas, and towels clustered near the beach where vacationers gaze at the crystal clear waters. But, swim out slightly farther and an entire underwater world enters into view. This is a coral reef! Bright fish, neon-colored anemones, and giant mammals swim through the maze of living coral.
What is this place, and how does it survive? How do the species interact with each other? These are the questions we’ll answer as we explore the food web and ecosystem of coral reefs.
What is a Food Web?
A food web is a diagram showing the transfer of energy between species. Since energy is transferred as food, food webs basically show who eats who in an ecosystem. Food webs are complex and involve many species, unlike a food chain, which shows the transfer of energy between single species.Food webs are organized into layers of who eats who called trophic levels. The bottom trophic level in a food web is the producers. Producers are organisms that make their own food.
They are usually green plants, but algae, bacteria, and other microscopic organisms may also be producers. Primary consumers eat producers, making them herbivores. Secondary consumers eat primary consumers, making them carnivores.
Tertiary consumers are the top predators in the ecosystem, eating both primary and secondary consumers.
What are Coral Reefs?
Coral Reefs are some of the most diverse ecosystems on Earth. Although they occupy less than one percent of the ocean, they hold nearly twenty-five percent of ocean life. Although coral look like plants, they’re actually animals, closely related to sea anemones. Coral reefs are usually found in tropical oceans near the coast. However, some coral reefs can be found in the deep sea, near hydrothermal vents, which spew chemicals and hot gases from the center of the earth.
These deep sea reefs grow slightly slower than the coastal coral reefs, but are nonetheless beautiful and have nearly as many different species as their coastal counterparts.
The Great Barrier Reef
The Great Barrier Reef is the largest coral reef in the world. Located off of the coast of Australia, it’s home to thousands of unique species found nowhere else in the world. The producers in the Great Barrier Reef are microscopic organisms called phytoplankton. Other larger producers, such as seaweed and seagrass, also provide energy. Primary consumers include thousands of fish, such as the brilliant parrotfish.Zooplankton, microscopic organisms, shrimp, clams, and other crustaceans are also primary consumers.
Larger fish, stingrays, octopi, and squid make up the secondary consumers, while sharks are the tertiary consumers, or top predators, in this ecosystem. Sharks eat large fish, seals, rays, squid, and octopi, keeping the food web in balance.
Deep Sea Coral Reefs
Although the most beautiful and diverse reefs occur near the coast, there are also reefs up to 20,000 feet below the surface of the ocean. This environment is cold and dark since no sunlight permeates to these depths. So, how do these species survive? The answer is chemosynthetic bacteria in deep sea vents, which use chemicals instead of sunlight to make their own food. They’re the producers of this ecosystem.
Zooplankton are the tiny primary consumers present in all marine ecosystems, which eat the producers. Giant, deep sea tube worms also eat the bacteria.Many species of fish, coral, shrimp, and starfish eat the zooplankton. Crabs, larger fish, squid, and octopi feed on these primary consumers. Other, spooky-looking animals, like the angler fish, lure larger secondary consumer fish in using special internal lights, which is known as bioluminescence.
A food web is a diagram that shows the transfer of energy between species in an ecosystem. Producers make their own food and form the base of the food web. Primary consumers eat the producers, and secondary consumers eat the primary consumers.
Tertiary consumers eat both primary and secondary consumers and keep the food web in balance.Coral reefs are hot spots of biodiversity. Coastal reefs, like the Great Barrier Reef, exist in warm water near the coast of tropical oceans. Seagrass, phytoplankton, and seaweeds are the producers.
Primary consumers like clams, shrimp, zooplankton, and small fish eat the producers. Larger fish, rays, and octopi are the secondary consumers, and sharks are the ultimate predator in this ecosystem, eating many types of primary and secondary consumers.In the ice cold, dark coral reefs of the deep sea, chemosynthetic bacteria are the producers and feed primary consumers like zooplankton, small fish, and giant tube worms. These, in turn, feed secondary consumers like larger fish, squid, and crabs.
The tertiary consumers of this food web include angler fish and other large, carnivorous fish.