1. Phytoplankton Michael L. Parsons Coastal Watershed Institute
Florida Gulf Coast University

2. Phytoplankton (microalgae)
Diatom (Pseudo-nitzschia)
Cyanobacteria (Microcystis)
Diatom (Actinoptychus)
Chlorophyte
Dinoflagellate (Karenia brevis)
Silicoflagellate
Dinoflagellate (Gambierdiscus)
Diatom (Chaetoceros)
Haptophyte

3. Overview The Good: phytoplankton are the base of the foodweb
The Bad: too much can have negative impacts
The Ugly: some phytoplankton can produce toxins that can kill animals and make people sick

4. Food Web

5. Phytoplankton Growth Requirements
Light
Nutrients (nitrogen, phosphorus, carbon, other compounds)
Can serve as indicators of nutrient loading and light availability

6. The Good
phytoplankton
fish
nutrients
plankton

7. The Bad

8. The Ugly

9. Phytoplankton and the Caloosahatchee
Many factors that affect the growth of phytoplankton in the Caloosahatchee are controlled/influenced by the flow of the river.
As flow increases:
nutrients  phytoplankton
residence time  phytoplankton
salinity  assemblage shift

10. flow  nutrients  phytoplankton
Doering et al. 2006

11. flow  residence time  phytoplankton
Wan et al. 2013

12. Doering et al. 2006

13. flow  residence time  phytoplankton
Wan et al. 2013

14. flow  salinity  assemblage shift

16. Andresen 2011

17. Andresen 2011

18. Red Tides and Caloosahatchee Discharges
Brand, unpub.

19. Brown et al. 2006

21. “The combined flux of N and P from TB, CH, and the Caloosahatchee River could theoretically supply 11–50% of the N and 11–57% of the P required to support growth of the measured population abundance for each of the three blooms”

22. Workshop Questions What driver is the indicator sensitive to?
Nutrients, salinity, light
What constitutes a healthy population of the indicator?
Low/moderate cell concentrations; more diatoms and less cyanobacteria and flagellates
Is the indicator a valued component of the Caloosahatchee system?
Should be!
What metrics are appropriate for assessing this indicator?
Chlorophyll concentrations; species identifications

23. Workshop Questions
What are the strengths and limitations of this indicator?
Chlorophyll is an easy (and strong) response variable to measure
Cofounding factors (salinity and nutrients; flow and residence time)
What are the relevant gaps and uncertainties in our understanding of the relationship between drivers/stressor and indicator response?
Teasing out nutrient loading versus residence time
Role of Caloosahatchee in red tides
Could our use of this indicator be improved to address additional drivers/stressors?
Yes – can help to optimize flow regimes in different conditions
Next steps?
River and red tides
Assemblage shifts versus flow