1. Aquatic Ecosystems

2. Aquatic Ecosystems Differ from terrestrial ecosystems
Temperature variations usually less pronounced
Salinity a major factor (Fresh water vs. salt water)
Three major groups of aquatic organisms-
1. Plankton (Microscopic, carried by current)
a. Zooplankton = Protozoans (animals)
b. Phytoplankton = Photosynthetic
2. Nekton- Large, swimming organisms (fish, turtles, etc.)
3. Benthos- Bottom dwelling organisms/Sessile and mobile

3. Benthic, plankton or nekton?

4. Freshwater Ecosystems
Flowing-water ecosystems change greatly between the source (start) and the mouth (end).

5. Source  headwater tributaries 
 flood plain  meanders  salt marsh  mouth  delta
The Hudson River
ADK’s to NYC:
Lake Tear of the Clouds …Albany…Newburg… NYC mouth (delta) …Atlantic ocean

6. Headwater Streams: are usually
shallow, cold, swiftly flowing, & highly oxygenated.

7. Rivers & Steams: Flowing-water Ecosystems
Rivers & Steams: Flowing-water Ecosystems. Streams with fast currents have organisms with adaptations such as sucker-mouth catfish (Plecos) and black fly larvae (suction disc).

9. Lakes & ponds: (Standing-Water Ecosystems) Standing-Water ecosystems are characterized by zonation. 1)Littoral zone 2) Limnetic Zone 3) Profundal Zone

10. 1)“Lit”toral Zone: shallow-water area along the shore
1)“Lit”toral Zone: shallow-water area along the shore. Plants include; Cattails, bur reeds, aquatic plants (Elodea), & Algae. This is the most productive section of a lake.

11. Animals include; Frogs, tadpoles,worms, crayfish, insect larvae, fishes like Perch, carp, & Bass. Water striders, whirligig beetles are often on the surface.

12. 2) Limnetic Zone: the open water beyond the littoral zone(away from the shore). This area extends as far as light can penetrate (photosynthesis). Main organisms are phytoplankton & zooplankton. Large fish are found here most of the time.

13. 3) Profundal Zone: this is the deepest zone
3) Profundal Zone: this is the deepest zone. Small bodies of water typically lack a profundal zone.

14. Thermal Stratification: the layering of large temperate lakes
Thermal Stratification: the layering of large temperate lakes. Temperature changes drastically with depth. Summer: Cool water remain at the bottom. A thermocline separates the warm (less dense) water from the cool deep section.

15. More oxygen dissolves (D. O. ) in water at cooler temperatures
More oxygen dissolves (D.O.) in water at cooler temperatures. Fall Turnover: falling temperature causes a mixing of the the layers. (temperate). Mixing ceases when the lake reaches a uniform temp. throughout.

18. Mangrove Forests are habitat for most larval shellfish, game fishes (Mullet, migratory birds, Manatee, mudskippers, snakes, crabs, & monkeys.