Topics: Eutrophication, Dead Zones, Plankton Bloom, Fertilizer Runoff
This is a simple lab, but has a lot of student work to it. It is designed to have 4 days of taking observations and measurements, but you can spread out those 4 days over as much time as you want. I do it over 2.5 weeks total. This provides great practice at taking measurements, recording data, graphing the data, and then applying the results to a real objective.
The only materials you need are:
Microcosms - small aquarium, large clear cups, soda bottle, etc
Liquid or pellet fertilizer
Pond water sample (a few gallons)
Nutrient test kit for water - N and P
You can students set up their own mini microcosms as a group, or you can do a large set for the entire class to sample from. I use small plastic aquariums (1 gallon of pond water in each? maybe a little less) and then use 0, 25, 50, and 75 ml for the control, low, med, and high treatments.
If you have them do it in small water bottles, just give them a number of drops to use instead - 0, 20, 40, 60
The lab is 6 pages long. There are 2 large data tables for recording DO, nitrates, and phosphates and then for phytoplankton counts as well. There are 3 large graphs set up for them to graph their data at the end.