Ocean - Session II.9 Four oceanic ecosystems


Classes study documents to learn about different oceanic ecosystems: coral reefs, abyssal zones, mangroves, and polar regions.

Key ideas

  • The ocean is home to a wide range of ecosystems, which can be fragile or subject to extreme conditions.

Inquiry methods

Document study


For each group:


Ecosystem, symbiosis, food web, coral, abyssal zone, mangrove, polar region


Between 1 hour and 1 hour 30 minutes

Introductory question

The teacher helps the class revise their knowledge of ecosystems, as discussed throughout this module and especially in Session II.5. He/she then asks: “Do you think the ocean has ecosystems where living conditions are unique – extreme or very fragile environments?” Pupils generally mention abyssal zones and coral reefs, but may come up with other examples.

Research: document study

To find out more, the teacher asks the class to work on four different ecosystems.  Pupils split into groups, each of which receives a document to study (Worksheet 25, 26, 27, or 28). Working independently, groups answer the following questions, which are written on the board:

  • How is this ecosystem unique? What are its main characteristics?
  • What are some examples of organisms living in this ecosystem?
  • Why is this ecosystem important for humans? (Is it well known?  Is it endangered?)

Group discussion and conclusion

After 20 minutes, each group choses a speaker to summarise their work for the rest of the class. Pupils describe all four ecosystems and their unique characteristics. They underline the wide variety of ecosystems that exist, and the many living organisms found there. They describe humans’ interactions with these environments (exploration, conservation, etc.). Following these discussions, pupils produce a joint conclusion, which they write in their science logbooks. For example:

There are many types of marine ecosystems, all of which have different characteristics. Conditions in these areas are sometimes difficult for the organisms that live there (for example, very low temperatures in the Antarctic, high pressure in abyssal zones, unstable soil in mangroves, etc.). We know very little about some ecosystems (such as abyssal zones). Others (such as mangroves) are located near human populations and suffer as a result of human activities.

Optional further study

There are many interesting documentaries on the Internet that the teacher could show the class as further study. For example, he/she may choose to show a video on "black smokers", hydrothermal vents where conditions for living organisms are extreme (in terms of light, temperature and the chemical environment). These zones are nevertheless home to many forms of life.

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