Trophic state index

High school (ages 12+)
Environment & Earth

Name:

Date:

Step 1 · Read the article

Open the article and read it at the level above. Then answer the questions below in your own words.

https://smallwhale.org/articles/trophic-state-index

Write what each word means, using the article.

Do not copy the article. Write two things you learned, the way you would explain them to a friend.

Answers below are taken from the article’s stored facts, so they match what the student read.

1. What is the index developer?Primarily associated with Robert Carlson Jr. in the late 1970s
2. What is the core parameters for calculation?Secchi disk depth, total phosphorus concentration, and chlorophyll-a concentration
3. How do scientists measure the TSI?Scientists measure the TSI by looking at several things: how deep a special disk stays in the water (Secchi depth), how much phosphorus is in the water, and how much algae is in the water. They use formulas to turn those measurements into one single score.
4. What does a low TSI value mean for a lake?A low TSI value, usually less than 30, means the lake is oligotrophic. It has very little nutrient, very clear water, lots of oxygen, and many kinds of fish and plants.

Limnology: The scientific study of the physical, chemical, and biological characteristics of inland waters.
Phytoplankton: Microscopic, plant-like organisms that drift in bodies of water, forming the base of the food web.
Hypoxia: A condition in which the body or a region of a body is deprived of adequate oxygen supply.