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 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 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) Marine Lifezone: Subcategories: * Coastal * Open Ocean (Sea) euphotic zone bathyal zone abyssal 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) Marine Lifezone: Subcategories: * Coastal * Open Ocean (Sea) euphotic zone bathyal zone abyssal 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 fish 3. Abyssal zone: bottom Dark, cold, little D.O., nutrients on floor Chemosynthetic bacteria at hydrothermal vents