The Bottom of the Food Chain
A lesson on the plants and animals at the bottom of the ocean food chain. The reading is accompanied by true/false questions.
• To introduce students to phytoplankton, zooplankton, algae and krill.
The ocean covers 71% of the earth?s surface. With the vast biodiversity on land it?s easy to assume that there are a multitude of marine organisms. In fact, new marine species are constantly being discovered as researchers use submersibles to explore the depths of the ocean. Just like on land, there are numerous different habitats in the ocean and marine creatures have adapted to fill the niches.
The smallest marine creatures are bacteria and, like on land, bacteria are everywhere in the ocean. Marine biologists estimate that there are 100 million bacteria in every gallon of seawater. Bacteria are also responsible for keeping the ocean clean by breaking down organic matter. Anaerobic bacteria break down oxygen containing compounds and release oxygen into the ocean.