II. Aquatic Biomes

A. Biome B. Terrestrial Biome C. Aquatic Biome

Biome

Major life zones characterized by vegetation type (terrestrial) or physical environment (aquatic)

Climate determines biomes

Terrestrial Biome

Characterized by vegetation and / or climate

Ex. temperate grasslands

Aquatic Biome

Aquatic biomes divided by zones- zonation

Can be vertical and horizontal

Vertical zonation defined by

Temp

Depth

Light

Horizontal zones defined by

Depth

Distance from shore

Temperature

Thermocline separates the warm upper layer from the cold deeper water in lakes/ ocean

Lakes undergo a semiannual mixing of their waters called turnover

Depth

• Benthic Zone: organic and inorganic sediment at bottom  ecological region at the bottom of any aquatic biome)

• The communities of organisms that live in the benthic zone= benthos 

  • Important in recycling and determining the type of sediment chemistry 

  • Do chemosynthesis from hydrothermal vents 

• Detritus (dead organic matter)

  • Falls from surface water and is a source of food

Light Penetration

Photic zone= light for photosynthesis

Aphotic zone= little or no light

Lakes

• Eutrophic lakes nutrient rich and low oxygen in deep zones

• Oligotrophic lakes = nutrient poor and oxygen rich (low primary productivity) 

Streams and Rivers

• The most prominent characteristic is = current

• Upstream is colder and more clear and low in nutrients (limited surface runoff)

• Downstream waters

1. Warmer

2. More turbid (cloudy)

3. Oxygenated

4. Wide

5. Silty bottoms (fine sediments accumulate at bottom of sediment)

Oceanic Pelagic Zone

• Oceanic pelagic zone is constantly mixed by wind- driven oceanic current

• Oxygen levels high, turnover driven by wind

• Lot of photosynthetic organisms like phytoplankton in these zones