Energy Flow in the Coral Reef Ecosystem

ENERGY FLOW IN THE CORAL REEF ECOSYSTEM Video Summary In this video segment, adapted from NOVA, learn how energy from sunlight is transferred through the inhabitants of the reef ecosystem. Photosynthesizing plants and algae convert light energy into chemical energy, which then gets passed through the food web to plant eaters, flesh eaters, and ultimately to scavengers and decomposers. www.teachersdomain.org/resources/hew06/sci/life/reg/foodweb Topics Covered: Recommended for Grades 3-12 – Life Science: Ecology Media Type: QuickTime Video – Life Science: Organisms and Their Environments Video Length: 3m 48s – Life Science: Regulation and Behavior Permitted use: Download, Share, Remix

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Discussion Questions  Why do you think the polyps only feed on plankton at night?  What do you think would happen to reef dwellers (e.g., coral, parrot fish, sea cucumbers) if the algae were not able to photosynthesize?  What is a double diet? What do you think the advantages are, if any, of having a double diet?  How does energy flow through the reef ecosystem?

Background Essay All living things require energy to carry out life functions such as growth, movement, and reproduction. For nearly all ecosystems—diverse collections of species that interact with each other and their physical environment—the major source of energy is the sun. The flow of energy tends to follow the same basic pattern whether the ecosystem is a tropical rainforest or a coral reef. To portray the transfer of energy through an ecosystem, ecologists use simple models called food chains. Organisms can be organized into different trophic levels, or positions in a food chain; organisms at higher trophic levels feed on those at lower levels.

Energy Flow in Coral Reef Ecosystem www.teachersdomain.org © 2007 WGBH Educational Foundation. All rights reserved. 1 As producers, plants and some microorganisms are an ecosystem’s foundation species. Producers make their own food from energy that comes directly from the sun. When sunlight enters a coral reef, for example, phytoplankton, algae, and plants such as sea grasses convert the light energy into chemical energy through the process of photosynthesis. However, not all organisms can make their own food. Consumers are organisms that obtain food and the energy stored within food by eating organisms. Consumers that feed only on plant life are called herbivores. Consumers that feed only on animals are called carnivores. Omnivores feed on both plants and other animals. Because organisms use about 90 percent of the energy they take in for their own survival and growth—leaving only about 10 percent for the consumer that eats it—there are fewer organisms supported in successively higher trophic levels. Scavengers and decomposers also play an important role in an ecosystem: They are its primary recyclers. Scavengers are animals that feed on dead members of different trophic levels. Decomposers, which include bacteria and fungi, break down organic waste material and return essential elements, such as nitrogen and phosphorous, to an ecosystem. While a food chain shows just one possible pathway along which energy can move, most consumers have more than one food source. To portray all feeding relationships in an ecosystem, a more complex model, called a food web, is used. Each organism in a food web plays an important role, so the loss of any one species due to environmental threats such as disease and pollution can disrupt a strand and thus may potentially threaten the health of an entire ecosystem. To learn more about the coral reef ecosystem and the relationships among different reef inhabitants, check out Coral Kid and Coral Reef Connections.

To learn more about how much energy is transferred from one level to the next within a food chain, check out Energy Flow.

To learn how certain organisms in an ecosystem break down dead plant and animal tissue to release nutrients for reuse, check out Decomposers.

To learn more about the ecological importance and fragility of life in another threatened ecosystem—the rainforest—check out Amazon Rainforest.

Lesson Plans Using This Resource: The Coral Reef Ecosystem

Curricular Standards Correlations: NSES, Project 2061, MCREL, and state standards correlations available at www.teachersdomain.org. (Free registration required for your specific state standards correlated to this resource.)

Materials used courtesy of: Aerial coral reef WGBH/ Peace River Films Underwater near the surface WGBH/ Peace River Films Wide shot algae WGBH/ Peace River Films Yellowtail eating a fish WGBH/ Peace River Films Truck into coral polyp circles WGBH/ Peace River Films Microscope view of one polyp WGBH/ Peace River Films Close up microscope view of one polyp WGBH/ Peace River Films Close up one baby polyp growing, timelapsed WGBH/ Peace River Films Close up one baby polyp growing (calcium carbonate mineral), timelapsed WGBH/ Peace River Films Pan close up on polyps in coral WGBH/ Peace River Films Coral polyps during the day WGBH/ Peace River Films Timelapse coral polyps extending tentacles WGBH/ Peace River Films Spiny blenny WGBH/ Peace River Films Spiny blenny WGBH/ Peace River Films Parrotfish WGBH/ Peace River Films Parrotfish WGBH/ Peace River Films Parrotfish WGBH/ Peace River Films Sea close upclose upmber WGBH/ Peace River Films Sea slug WGBH/ Peace River Films Close up sea slug waves on back WGBH/ Peace River Films Close up chloroplasts in sea slug waves on back WGBH/ Peace River Films Close up sea slug WGBH/ Peace River Films Herbivore fish in coral reef WGBH/ Peace River Films Close up overgrown algae WGBH/ Peace River Films Long spined sea urchin on coral WGBH/ Peace River Films Long spined sea urchin - mouth WGBH/ Peace River Films Long spined sea urchin - moving long WGBH/ Peace River Films Yellowtail snapper persuing a fish WGBH/ Peace River Films Big ugly fish eats another fish WGBH/ Peace River Films Baracuda cruises overhead WGBH/ Peace River Films Baracuda cruises overhead WGBH/ Peace River Films Baracuda catches a fish WGBH/ Peace River Films Sea urchin in cave WGBH/ Peace River Films Sea urchin out to feed at night WGBH/ Peace River Films Yellowtail snapper swimming WGBH/ Peace River Films Yellowtail snapper catching a fish WGBH/ Peace River Films Lobster WGBH/ Peace River Films Wideshot underwater coral reef WGBH/ Peace River Films Underwater deep in coral reef, looking up toward sun WGBH/ Peace River Films Close up overgrown algae WGBH/ Peace River Films Yellowtail snapper persuing a fish WGBH/ Peace River Films Lobster WGBH/ Peace River Films

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