Teacher preparation:

Overarching learning goal: Students recognise the range of abiotic and biotic conditions that are required to support a shallow-water coral reef and identify coral reef food chains. Students also reflect upon the threats to coral reefs from human activities, including climate change.

Teacher content information: Coral reefs are often referred to as “the rainforests of the ocean”: they are among the most diverse ecosystems on the planet. They support a huge range of marine creatures, some of who spend their whole lives living on these reefs and others just drop by to visit the reef for food or a clean. Some creature visit the reef for shelter or food at certain times of the year while others come to breed and provide a place for their young to mature away from the predators of the open ocean.

Coral reefs occupy less than 0.1% of the world’s ocean surface yet they provide a home for 25% of all marine species, including fish, molluscs, worms, crustaceans, echinoderms, sponges, tunicates and other cnidarians. All these creatures play an important part in sustaining a reef, from cleaning to decomposing to providing food and shelter.

In this activity students will create their own coral reef, researching the conditions, creatures and vegetation required for sustaining a reef and representing their research through a 3D model of a coral reef.

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Students can complete this activity in groups or as a class. If you decide to work as a class, you could consider dividing the activity into 12 groups for the research (each group addressing one research point), and dividing the design and development into groups (some groups addressing abiotic features, some addressing biotic features, other groups creating the supporting written information).

Student and classroom organisation:

Step 1.

Students can work in groups or as a class.

Students will need to begin this activity by researching the various occupations (niches) that need to be filled to make a coral reef ecosystem work, and what kinds of organisms fill these roles. Ask students to start the process by brainstorming some of these roles amongst themselves. For example, they may identify the need for a source of energy to sustain the reef system (which implies one or more food chains), some means for disposing of wastes, a source of oxygen etc.

Students will then need to research these issues in more detail. Using the list of factors below, ask students to undertake research on the Internet to learn more about the biotic and abiotic required to sustain a shallow-water coral reef, including (the following information is also available on the student worksheet):

Energy - students should recognise that the primary source of energy in coral reef systems is sunlight that is converted to chemical energy by green plants through photosynthesis. What other energy sources are present on a reef system?
Waste - in nature, by-products from one organism are “raw materials” for another organism.
Oxygen - how does oxygen move through the reef system?
Food chains - How many food chains can they find and how many links can they find in these food chains?
Water temperature - most shallow-water corals are tropical and need water temperatures between 18°C and 32°C.
Water movement - some water movement is very important for the transport of food particles to sessile organisms, as well as for the removal of metabolic by-products that would be toxic if allowed to accumulate. Too much water movement (including waves) can limit coral reef growth.
Location - What are the conditions required to sustain a reef, e.g. depth, distance to shore, atmospheric temperature.
Salinity - Corals tend to live in salty water, surviving in a range of 27-40 parts per thousand (ppt) but preferring 36 ppt.
Foundations for reef - A hard substrate is also necessary for the corals to settle on; they cannot settle and grow on soft sediment successfully.
Marine creatures and vegetation living on the reef
Marine creatures and vegetation living around the reef
Migrating marine creatures visiting the reef

Ask students to research all these points thoroughly as they will need to provide information to accompany their 3D reef.

Step 2.

Once students have comprehensively researched the reef, they can begin to design their reef. Students should be given free reign to model the reef in any manner they choose, from paper and cardboard, to textiles, to computer-aided design, to a realistic water tank design. However, students should follow a design brief that could include the following points:

At least 15 biotic elements of the reef should be represented
At least 5 abiotic elements of the reef should be represented
At least 1 food chain should be represented
The 3D model should be accompanied by explanatory notes or a booklet - these need to be comprehensive and should address all the biotic and abiotic features of a shallow water coral that were researched.

Step 3.

Ask students to present their coral reef, and to discuss how they met the challenges outlined in the design brief.

Reflection

Ask students to complete the reflection questions provided on the Student Worksheet.

Extension/Homework

Ask students to research how their shallow-water coral reef system compares to a deep-water coral reef system.

Earth Hour - Build a Coral Reef

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