Modelling marine stressors and tipping points

Simply defined, a tipping point is the point when a number of changes or incidents become significant enough to cause a large change in the way a system functions. The tipping point concept is used across many disciplines. When used in an ecological setting, scientists generally regard a tipping point as when an ecosystem moves from something of value to one less valued.

Global examples of marine tipping points include collapsed fisheries, coastal dead zones and dying coral reefs. In New Zealand, we’ve crossed tipping points when the overharvesting of toheroa and mussels caused population collapses and losses of ecosystem services.

Marine ecosystem stressors game

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Wooden blocks can represent marine stressors. As stressors build up, the marine ecosystem reaches a tipping point.

Rights: The University of Waikato Te Whare Wānanga o Waikato

In this activity, students research and identify marine stressors and play a game, similar to Jenga, to simulate how small changes and stressors can lead to an ecosystem tipping point. The game uses 15–30 blocks from a Jenga set or similar items like dominoes, Cuisenaire rods, tens (place value) blocks or wooden blocks.

By the end of this activity, students should be able to:

• use online resources to locate information about marine stressors

• provide simple explanations about how the stressors affect marine ecosystems

• create and play a game to model stressors and tipping points

• discuss how this game accurately (or inaccurately) represents a marine tipping point model

• discuss if/how marine tipping points can be reversed.

Download the Word file (see link below) for:

• background information for teachers

• teacher instructions

• student instructions.