Lesson IV Viva la Difference!
Overview: Florida’s freshwater lakes, rivers and ponds are different from those found up north and other regions of the U.S. For example, many of Florida’s waterbodies have an abundance of large plants (macrophytes) or microscopic plants (algae). Sometimes they have both. This has a lot to do with naturally occurring nutrients that are plentiful in our soils and the fact that most of our lakes are shallow (less than 12 ft) warm water systems. All of these factors affect a lake’s biological productivity. Add invasive plants to the equation and things get even more interesting.
PPT = PowerPoint™ Presentation |
UE = upper elementary |
MS = middle school |
HS = high school |
Key Points
- Lakes and other freshwater systems are often described by their physical characteristics (the color or clarity of thewater, wildlife nearby, etc. However, that’s just a part of the story. There are a number of important biological indicators that scientists use to “describe” lakes: chlorophyll (algae), phosphorus, nitrogen and Secchi depth.
- These indicators also serve as criteria for the Trophic State Classification System, which is, simply put, a method for classifying lakes based on their biological productivity.
- Florida lakes are different from lakes up north for several reasons:
1) naturally occurring nutrients in our soils (in certain areas),
2) shallow depths (which allow light to easily reach submersed plants);
3) year ‘round sunlight;
4) warm climate.
- Invasive plants can alter a lake’s native plant communities and also its normal biological productivity (trophic state).
Keywords
algae, aquatic, biological productivity, chlorophyll, clarity, classification system, ecosystem, emersed plants, (eu-) eutrophic, floating plants, floating-leaved plants, food web, (hyper-) hyper-eutrophic , invasive plants, limnologist, macrophytes, (meso-) mesotrophic, microscopic, nutrients, (oligo-) oligotrophic , parameters, Secchi disk, soils , submersed plants, total phosphorous (TP), total nitrogen (TN), transparency, trophic state, vegetation, water clarity, water color
Concept Map
Coming soon.
Main Activities
- Viva la difference! PPT (UE, MS, HS) – Includes discussion about various characteristics used to describe lakes and how they are used to assess the trophic state (biological productivity) of a waterbody, with emphasis on how Florida freshwater systems differ from those found in other parts of the country. Program also discusses why we need to know this in the first place. Downloadable viewing questions and vocabulary. Q & A provided at the end. - Coming soon.
PowerPoint™ Notes - Word Document (118 KB) | PDF File (62 KB) | HTML
- Invasive Plant Survey (UE) – This activity is designed to be used over a period of time so students can observe the ecological systems that are being invaded with non-native plants.
- Trophic State Word Search (UE, MS, HS) – Students develop vocabulary by searching and identifying key words related to the trophic state classification system.
- Trophic State Crossword Puzzle (UE, MS) - Students develop vocabulary by reading clues and completing a CW puzzle.
Lab Activities
- Water Hyacinth Transpiration (HS) - Students will be able to define evaporation, transpiration, and evapotranspiration. They will be able to describe factors that affect rates of evapotranspiration on a water body including the effects of water hyacinths. Lastly, students will be able to describe the impact of having an uncontrolled population of water hyacinths on a water body. Word (117 KB)
- Secchi depth (see the pennies lab) - Coming soon.
Additional Resources (activities, fact sheets, labs, illustrations, etc.)
