Vocabulary:  Eutrophication: is a natural process; where lakes, as they age, build up nutrients which cause phytoplankton to grow.  Phytoplankton: Microscopic free-floating aquatic photosynthetic organisms such as algae and cyanobacteria.

Vocabulary:  Nutrients: two of the most important nutrients that algae use: Nitrogen in the form of Ammonia (NH4+/NH3,) Nitrite (NO2-), Nitrate (NO3-), and Phosphorus. (PO4-3).

Vocabulary:  Cultural Eutrophication: refers to the addition of nutrients from human activities.  The most common ways that humans directly or indirectly affect eutrophication are through: waste water/sewer effluent, drinking water treatment, fertilizer run-off, farm animal waste, industrial discharge, and the paving of land with concrete.

Vocabulary:  Oligotrophic with low levels of nutrients and phytoplankton (Lake Tahoe), Mesotrophic with rising levels of phytoplankton and nutrients (Lake Berryessa),  Eutrophic or Hypertrophic with very high levels of phytoplankton and nutrients, murky appearance, where many species can not survive (Tai Hu in China).

Vocabulary:  Ways to measure eutrophication:  Dissolved Oxygen is the measure of oxygen in the water, which is necessary for most aquatic life. Algal blooms lead to a decrease in total dissolved oxygen by causing explosion in bacteria that decompose the decaying organic materials, which deplete oxygen levels below the surface.

Vocabulary:  Ways to measure eutrophication: Dissolved Oxygen is the measure of oxygen in the water, which is necessary for most aquatic life. Algal blooms lead to a decrease in total dissolved oxygen by causing explosion in bacteria that decompose the decaying organic materials, which deplete oxygen levels below the surface.

Vocabulary:  Another way to measure eutrophication is by measuring light attenuation, which is basically how much light is blocked by the algae. In extreme algal blooms, the algae blocks light from penetrating the first few feet of water, causing deaths and oxygen dead zones.

Our Experiments:  In this two week-long lesson you will study the effects of different variables, representing effects of human activities, on algal growth in water bottles

Our Experiments:  You will chose a variable that you would like to test, and add it to a bottle filled with distilled water and algae. We will also compare your results to a negative control (distilled water + algae), and several positive controls (distilled water + nitrogen + phosphorus+ algae). These bottles will be placed under grow lights for 14 (or more) days.

Our Experiments:  The possible variables that you can choose from include:  - Plant food (organic fertilizer, inorganic plant food, worm tea)  - Organic waste (grass clippings, fish food, compost, sugar)  - Things that alter water chemistry, pH or salinity

Our Experiments:  We will be measuring algal growth using a machine called a spectrophotometer, which basically measure how much light (at a specific wavelength) is able to pass through a small glass vial. The less light that can pass through (transparency) the more algae growth.  Finally, you will present your data, and discuss your results as part of a presentation in front of the class.