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-

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

Plankton, nekton or benthic?

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

Mount Marcy- Elevation 5344 ft.

http://images.google.com/url?q=http://campus.greenmtn.edu/dept/es/hudson_river/pictures/steve.bmp&usg=AFQjCNGn5Kt6kZyPbETPIjPJSIEpCmdzlg

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 Ecosystems Lakes & 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.

Mangrove Swamps of the World

The Open Ocean

The open ocean is or is not a highly productive ecosystem?

Coral Reefs

Coral Reefs of the world

Changes of the Florida Everglades