Idea for Use in the Classroom

Henderson Island in the South Pacific was named a United Nations Educational, Scientific and Cultural Organization (UNESCO) World Heritage site in 1988. At the time, it was one of the few atolls in the world unspoiled by human activity. In 2017, however, researchers surveying the island’s beaches found the highest concentration of plastic trash ever recorded.

In this infographic, the colored dots show the amount of plastic and other trash collected in one survey plot. What items were most common? What items were the least common? Using the infographic and a world map, point out the pattern of ocean currents. Where does the plastic pollution on Henderson Island come from? How did it get there?

The trash survey was conducted on a beach. But to get to the beach, the trash had to float through the water, which is where coral reef organisms would have encountered it. Ask students to predict what kinds of floating trash might be most harmful to ocean life and why. Would any of the trash be harmless?

Use this encyclopedia article on food webs and the article on coral reef food webs to introduce students to a typical coral reef food web. In small groups, explore the impact of ocean plastics on coral reef species by having students research the impact of “ghost nets” on sea turtles, the ingestion of plastic by Pacific seabirds, and the ingestion of plastic particles by coral polyps. Have each group report their findings to the class. Ask students to predict what might happen if turtles or seabirds become less common in a coral reef ecosystem. What would happen if the corals died off?