aquatic life zones: 2 major categories
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Aquatic Life Zones: 2 major categories. Marine (saltwater) Or 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 - PowerPoint PPT PresentationTRANSCRIPT
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 • 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 feedersPlates (baleen) hang from upper jaw – filter plankton from waterincludes: 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 zonebathyal zoneabyssal zone
Subcategory: Coastal
• 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
•
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 zonebathyal zoneabyssal zone
Subcategory: Open Ocean 1. Euphotic zone: top
• 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 fish3. Abyssal zone: bottom • Dark, cold, little D.O., nutrients on floor• Chemosynthetic bacteria at hydrothermal
vents