1. Phytoplankton Anabaena (filamentous blue-green) Asterionella
(colonial diatom)
Scenedesmus
(colonial green)

2. Metaphyton columns

3. Dominant Genera of Metaphyton
Cladophora
Oedogonium
Rhizoclonium
Spirogyra
Hydrodictyon
Lyngbya

4. Metaphyton and Nutrients
Filaments originate on the bottom under conditions of low light and high nutrients.
They end up at the surface, faced with high light and lower nutrients.
The metaphyton may act as “nutrient pumps”, transporting nutrients from the sediments to the water column.

5. Attached Algae (Periphyton)
A microscopic forest

6. Attached Algae (Periphyton)
A 3-dimensional “forest”, with ground cover, a shrub layer and canopy species
Light normally comes from above
Nutrients come from either the water column or substrate

7. Filamentous green alga with epiphytic diatoms

8. Centric Diatoms
Girdle
Cyclotella (valve view)
Melosira (girdle view)

9. Pennate Diatoms
Gomphonema (stalked)
Epithemia (adnate)

10. Algae biomass reflects local conditions

11. Effects of Nutrient Enrichment on Algal Growth
Increased overall growth
A few species become very abundant
Rarer species may disappear
The 3-dimensional structure of the community changes (filaments become increasingly dominant)

13. What happens when there’s too much algal growth in a pond or stream?

15. Chlorine – Used to disinfect
Chlorine – Used to disinfect. When found as free chlorine, can be a sign of tap water or sewage leak.
Alkalinity – Amount of carbonate (CO32-) in the water. Can be a measure of the ability of a solution to neutralize acids.
Total Hardness - Hard water has a high mineral content (in contrast with soft water). Hard water minerals primarily consist of calcium (Ca2+), and magnesium (Mg2+) and bicarbonates and sulfates (CaMg(CO3)2).

16. Nitrogen Compounds Ammonia Nitrite Nitrates
Ammonia – Can be formed from rotting things or urine. Can be taken up by plants.
Nitrite - NO2− Not very stable, changes quickly to nitrates
Nitrate - NO3− A form of Nitrogen that is usable for plants and animals.

17. Dissolved Oxygen
Dissolved oxygen analysis measures the amount of gaseous oxygen (O2) in in the water.
Oxygen gets into water by diffusion from the surrounding air, by aeration (rapid movement), and as a product of photosynthesis.