Begin by selecting a freshwater or marine aquatic ecosystem as a model for your food web. Be specific. Choose a specific lake. Or, if you choose an ocean ecosystem, identify its geographical area and depth. Keep in mind that deep-sea organisms live in a completely different environment than surface aquatic organisms.

Next, conduct research on the following conditions in the ecosystem you chose. They influence the types of organisms that can live there.

geographical features
temperature
depth/light availability
salinity
pH
unique features that contribute to the ecosystem, such as other bodies of water that connect to it, unusual chemistry, and climate
Using the information you gathered, write a paragraph that describes conditions in the ecosystem.