Analyze the dissolved oxygen (DO) content of various water samples at different temperatures via the Winkler method in order to understand how varying physical factors play a role in gas solubility. Students will also measure primary productivity in a pond ecosystem using screens to simulate decreasing light levels at increased depths. Background information includes an overview of the importance of oxygen and carbon dioxide in biological systems as well as how primary productivity relates to the metabolism of organisms in these systems. Neo/Sci. Note: Water sampler required, purchase separately below.