Transcript Aquatic Life Zones

Aquatic Life Zones:
2 major categories
1. Marine (saltwater) Or
2. Freshwater
Types of organisms determined
by:
• Salinity
• Temperature
• Sunlight availability
• D.O. (dissolved oxygen)
• Nutrient availability
Major types of Organisms
• Plankton: small free-floating
organisms
– Phytoplankton: plant-like
• Photosynthetic
• diatoms, protists, etc
- Zooplankton: animal-like
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Heterotrophic
Protozoans
Larvae
Copopods, cnidarians, krill…etc.
- Ultraplankton: TINY (less than 2 micrometers)
• includes bacteria
• Benthos (benthic organisms): bottom
dwellers – anchor to one spot, burrow, or
walk along bottom
• Nekton: active swimmers – don’t follow
currents
Baleen whales: filter feeders
Plates (baleen) hang from upper
jaw – filter plankton from water
includes: humpbacks and blue whales
Toothed whales: teeth used to bite
and chew food
includes:orca (killer whale) and sperm whale
Marine Lifezone:
Subcategories:
* Coastal
* Open Ocean (Sea)
euphotic zone
bathyal zone
abyssal zone
Subcategory: Coastal
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High tide to Continental shelf
(Ample sunlight) high NPP
90% of all marine species
1. Coral reefs: MOST biodiverse areas of all
aquatic life zones
– “The Aquatic Rainforest”
– Hundreds of thousands of coral polyps
excrete CaCO3 skeletons
– Grow slowly, disrupted easily:
• Biggest threat: sediment run-off
• Bleaching (even from 1 degree temp
increase)
• Removal (aquariums/jewelry)
• Pollution
• Damage (tourists, anchors, natural
disasters)
• Overfishing
• Cyanide/dynamite “fishing”
–1 m2 of reef killed for every fish caught
2. Intertidal zone: shoreline between low and
high tide
• Tides caused by gravitational pull of moon
• Organisms adapted to HARSH conditions
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3. Barrier Islands: islands separated from
the mainland by a shallow sound, bay, or
lagoon
• Constantly shifting beaches due to erosion
– Can be helped with a jetty
• Dunes – backbone that provides stability
– Plants hold sand in place
– Protect from natural disasters
4. Coastal wetlands: inlets, bays, sounds,
Mangrove forest swamps
5. Estuary: where freshwater meets
saltwater (mouth of a river)
Marine Lifezone:
Subcategories:
* Coastal
* Open Ocean (Sea)
euphotic zone
bathyal zone
abyssal zone
Subcategory: Open Ocean
1. Euphotic zone: top
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Sunlight layer: phtyoplankton =
photosynthesis: HIGH D.O. (dissolved
oxygen) and low dissolved CO2, big fish and
mammals
2. Bathyal zone: middle
• Dimly lit – little/no producers, zooplankton,
smaller fish
3. Abyssal zone: bottom
• Dark, cold, little D.O., nutrients on floor
• Chemosynthetic bacteria at hydrothermal
vents