Aquatic Succession

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Purpose

To observe the effects of nutrients on aquatic succession.

Procedure

1. Obtain 5 clear containers of lake/river water that already contains some algae.
2. Place equal amounts of water in each container, and make initial observations.
3. Label the containers 0, 1x, 2x, 3x, 4x.
4. Obtain a general fertilizer (liquid is best).
5. In the container labeled '0', place no fertilizer.
6. Place an amount (e.g., a teaspoon would be plenty for an average fish bowl or 2000 mL beaker; it depends on the size of your container) in the container labeled 1x.
7. Place twice the amount in 2x, three times in 3x, and four times in 4x.
8. Place the containers in a sunny area or under lights.
9. Observe the containers once a week for a period of six weeks; if aquatic succession is indeed accelerated due to nutrient enrichment, the containers with the highest levels of fertilizers should contain the most algae. There may be a level that becomes toxic. This, too, can be used as an inquiry lesson.