Crystal Clear or Muddy Lake?
Data Story
Students examine data about the clarity (Secchi depth) of two lakes in Maine and wonder about water quality research.
Welcome to this Tuva data story! Lakes are great for swimming, fishing, and other recreational activities. Swimming in a clear blue lake on a warm day can be delightful, but swimming in a green or muddy lake can be much less enticing. The clarity (transparency) of water in a lake is one indicator of water quality. Transparency is how easily light passes through the water. Biologists measure the transparency of lake water as an indicator of a lake’s nutrient status, or "Trophic State Index" (TSI). The TSI classifies lakes according to how many nutrients are available to support fish, plants, and other aquatic organisms. Lakes with a lot of nutrients (high TSI) tend to have low transparency. The abundance of nutrients causes algae to flourish and block light from reaching deeply. Transparency also decreases (and TSI increases) when sediments are suspended in the water. To measure water transparency, researchers lower a black and white metal "Secchi" disk into the water. The depth at which the disk is no longer visible from above is called the Secchi depth of the lake. In this data story, you will explore the trophic state of two lakes in Maine, China Lake, and Allagash Lake. Click Next to get started!
Topics and standards: Science, Life Science, Ecosystems, Ecosystem Relationships, Abiotic-Biotic Interactions, Grades 9-12, Notice-Think-Wonder