The document provides an overview of aquatic ecology, focusing on various types of aquatic ecosystems, hydrology, and the function of different lake zones. It explains how nutrient availability, particularly nitrogen and phosphorus, influences productivity and food webs in lakes and ponds. Additionally, it discusses the importance of managing nutrient levels to maintain healthy aquatic environments.

1. Aquatic Ecology 101

2. Outline Types of aquatic ecosystems Hydrology of lakes and ponds Lake zones and processes Aquatic food web Lake trophic states Concept of limiting nutrient

3. Types of Aquatic Systems Lakes & Ponds Rivers & Streams Wetlands Estuaries Marine system Groundwater

4. Lakes and Ponds Critical differences from other freshwater systems Longer residence time Typically not shaded with most of the surface area exposed to sunlight Florida lakes are typically shallow and well mixed Florida lakes are often highly colored, but can have light reaching much of the bottom Photo by Bill Wade

5. Watershed / Lake Area Ratio Watershed area relative to lake area will influence the residence time of water in the lake. This ratio is also a factor in the nutrient loading to the lake

6. Lake Habitat Zones

7. Lake Littoral Zone Functions Intercepts Nutrients Refuge from Predators Nursery for Fish Oligotrophic Northern Lake Eutrophic Southern Lake

8. Lake Limnetic/Pelagic Zone Functions Plankton Zooplankton

9. Submerged Aquatic Vegetation (SAV) Nutrient uptake Sediment stabilization Habitat Oxygen production Lake Limnetic / Pelagic Zone

10. Pond Food Web Nutrients Algae/Plants Grazers Fish Nutrients Algae/Plants Grazers Fish

11. Relationship Between Nutrients and Pond Productivity Nutrients Algae/Plants Grazers Fish Nutrients Nutrients Nutrients Nutrients Habitat/Environmental Impacts Algae/Plants Grazers Fish Algae/Plants Grazers Fish Algae/Plants Grazers Fish Algae/Plants Grazers Fish

12. Low nutrients Low primary productivity Low grazers and insects Low fish production Clear water Sandy/low organic matter on bottom

13. TROPHIC STATE Moderate nutrients Increased primary productivity More grazers and insects More fish production Moderate water clarity More aquatic plants Some organic sediment accumulation

14. TROPHIC STATE High nutrients High primary productivity Large number of grazers and insects Moderate fish production Low water clarity, or Clear with aquatic plants High organic sediment accumulation

15. Trophic State Change Nutrients & Productivity Sediment & Accumulation Species Shifts Species Richness

16. Manipulating Pond Response to Nutrients Fish Grazers Nutrients Algae/Plants Grazers Fish X Algae/Plants X Source of the problem

17. Limiting Nutrient Concept … Plants need nutrients to grow Nitrogen and Phosphorus are the main nutrients For every unit of N you need so many units of P If one nutrient is not in sufficient supply it will limit the total production potential. For algae N:P > 17 Phosphorus Limited N:P < 10 Nitrogen Limited 10 < N:P < 17 Co-Limitation N:P < 22 will tend to promote Cyanobacteria which are nitrogen fixers

18. Phosphorus Limitation: Lake 227

19. Total Phosphorus / Chlorophyll-a Relationship Phosphorus is typically liming nutrient in freshwater Nitrogen is typically limiting nutrient in marine system.

20. Summary Lakes have longer residence time and more light than other freshwater systems Littoral Zone, Pelagic Zone, Submerged Aquatic Vegetation Nutrients regulate algae > grazers > fish Removing algae doesn’t remove nutrient regulator Phosphorus is typical nutrient limiting nutrients depending on N:P ratio Stormwater ponds respond just like lakes do to nutrients

21. Questions?