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Chapter 6. Biomes and Aquatic Ecosystems. Aquatic Ecosystems. 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-
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Chapter 6 Biomes and Aquatic Ecosystems
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
Freshwater Ecosystems • Flowing-water ecosystems change greatly between the source (start) and the mouth (end).
Source headwater tributaries flood plain meanders Estuary (Salt marsh) mouth delta The Hudson River • ADK’s to NYC: Lake Tear of the Clouds …Albany…Newburg… NYC mouth (delta) …Atlantic ocean
Headwater Streams: are usually shallow, cold, swiftly flowing, & highly oxygenated.
Rivers & Steams:Flowing-water Ecosystems. Streams with fast currents have organisms with adaptations such as sucker-mouth catfish, fish with streamlined bodies, and black fly larvae (suction disc).
Estuaries • Where “rivers meet the sea” • Very productive ecosystems!
Standing-Water EcosystemsLakes & ponds- Standing-Water ecosystems are characterized by zonation.1)Littoral zone2) Limnetic Zone3) Profundal Zone
“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.
Animals include; Frogs, tadpoles,worms, crayfish, insect larvae, fishes like Perch, carp, & Bass. Water striders, whirligig beetles are often on the surface.
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.
3) Profundal Zone: this is the deepest zone. Small bodies of water typically lack a profundal zone.
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.
More oxygen dissolves (D.O.) in water at cooler temperatures.Fall Turnover: falling temperature causes a mixing of the the layers. Mixing ceases when the lake reaches a uniform temp. throughout.
Mangrove Forests are habitat for most larval shellfish, game fishes (Mullet, migratory birds, Manatee, mudskippers, snakes, crabs, & monkeys.
The Open Ocean The open ocean isor is not a highly productive ecosystem?