1. How Do You Know an Ecosystem is Healthy?

2. There are many factors used to assess health
Turbidity
Dissolved Oxygen
Nutrients (Phosphorus, Nitrogen)
Bioassays

3. Turbidity Measure of suspended particles
Particles can be silt, soil, floating vegetation and organisms
Can be affected by rainfall
Can be caused by humans: runoff, erosion, boating

4. Dissolved Oxygen Concentration of Oxygen in the water
Critical for organisms to live
Fluctuates daily and seasonally
Must be above 5.0 mg/L to support wildlife
Decaying material consumes Oxygen

5. Nutrients Nitrogen and Phosphorus are important measures
High Nitrogen and Phosphorus amounts can increase algal growth
Humans can contribute nutrients through excessive fertilizer use

6. Bioassays Some species are important indicators of health
Examine ecosystem to look for “normal” conditions
Some organisms (e.g., algae) will increase in population when the system is out of balance

7. References
Pinto, G., Bielmyer-Fraser, G.K., Goldberg, N., Ouellette, A., Le, A., Pyati, R., Zoellner, B., Closmann, C. (2018/19) State of the River Report for the Lower St. Johns River Basin, Florida: Water Quality, Fisheries, Aquatic Life, & Contaminants (LSJR). Prepared for the City of Jacksonville, Environmental Protection Board.