1. Nutrients and Algae

2. Major Algal Nutrients Phosphorus - taken up by algae as orthophosphate (PO 4 3- ). Nitrogen - taken up by algae as nitrate (NO 3 - ) or ammonia (NH 4 + ) Silica - used in large amounts by diatoms to make their glass shells

3. Sources of Nutrients Point Source Pollution – comes out of a pipe

4. Sewage Treatment Plant

5. Sources of Nutrients Non-Point Source Pollution - Washes into the water

6. Agriculture

7. Fertilized Lawns

8. Septic Fields

9. Rain & the Atmosphere

10. An Example: Crow Hill Pond Topographic Map of the Watershed or Catchment

13. Aquatic Food Web Nutrients and Light Floating Algae (Phytoplankton) Algae Blobs (Periphyton and Metaphyton) Water Plants (Macrophytes) Zooplankton Bottom Critters (Benthic Invertebrates) Fish