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 1. Plankton: small free-floating organisms 2. Phytoplankton: plant-like Photosynthetic Algae, cyanobacteria
3. Zooplankton: animal-like Heterotrophic Protozoans Larvae Copopods, cnidarians, krill…etc. 4. Ultraplankton: TINY (less than 2 micrometers) includes bacteria
5. Benthos (benthic organisms): bottom dwellers – anchor to one spot, burrow, or walk along bottom
6. Nekton: active swimmers – don’t follow currents
7. Baleen whales: filter feeders Plates (baleen) hang from upper jaw – filter plankton from water includes: 8. humpbacks and 9. blue whales
10. Toothed whales: teeth used to bite and chew food includes: 11 10. Toothed whales: teeth used to bite and chew food includes: 11. orca (killer whale) and 12. sperm whale
13. A Marine Food Chain (example)
Marine Lifezones
13. Coastal/Neritic High tide to Continental shelf (Ample sunlight) so: high 14.NPP and D.O. 90% of all marine species
15. Coral reefs (in the coastal zone): 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 threats: 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
16. Intertidal zone: shoreline between low and high tide Tides caused by gravitational pull of moon Organisms adapted to HARSH conditions (wet/dry, warm/cold, salty/not-so-much)
17. 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
19. Coastal wetlands: inlets, bays, sounds, Mangrove forest swamps
20. Estuary: where freshwater meets saltwater (mouth of a river)
22. Pelagic or Open Ocean
Side-note: Low NPP per unit area, but adds up!! 23. Epipelagic or photic zone: TOP Sunlight layer: warmer water, phytoplankton = 24. photosynthesis: HIGH D.O. (dissolved -oxygen); big fish and mammals Side-note: Low NPP per unit area, but adds up!!
25. mesopelagic and bathyalpelagic zones: MIDDLE Dimly lit/dark – twilight/midnight regions little/no producers (little 26. D.O.), - zooplankton, smaller fish, squid
27. Abyssal or Abyssopelagic zone: bottom (The Deep Dark Abyss!) Dark, cold, varying D.O. , nutrients on floor Organisms adapted to HIGH pressure, COLD temps, NO light! Bioluminescence adaptation Chemosynthetic bacteria at hydrothermal vents
28. Equation: 6CO2 + 6H2O + 3H2S C6H12O6 + sulfur compounds
29. Hadel Zone… Or Hadelpelagic zone… - Deepest trenches in ocean Side-notes: Average ocean depth 2.3 miles or approx 12,000 ft Deepest hadel zone point: 30. Challenger Deep (part of Mariana Trench) = approx 36,000 feet or 6.8 miles deep! Approx 16,000 psi of pressure… compared to about 14 psi at surface