1. The Ocean Depths

2. Zones of the Ocean Epipelagic- Photic Zone (500- 650 ft)
Sun, plants, photosynthesis, O2
Mesopelagic- Dim light, but no plants
No photosynthesis ft
Deep sea- perpetually dark

3. Overturn- oxygen rich water reaches the bottom in the Atlantic (S
Overturn- oxygen rich water reaches the bottom in the Atlantic (S. of Greenland) and just north of Antarctica
Great Ocean Conveyer- regulates the Earth’s climate and replenishes oxygen to the deep sea.

4. The Twilight World- (the Mesopelagic) 3,000 ft- dim light
Main thermocline- large temperature change
Animals: Midwater
***have photophores = bioluminescence
Zooplankton Copepods***
Siphonophores Krill ***
Shrimps*** Comb Jellies
Ostracods Larvaceans
Amphipods Pteropods
Chaetognaths Squids
Jellyfish Vampire squid

5. Mesopelagic Fish: 1. Bristlemouth
Most abundant fish on earth

6. 2. Viperfish

7. 3. Dragonfish

8. 4. Hachetfish

9. Mesopelagic Adaptations
Only about 20 % of food produced in the epipelagic makes it to the mesopelagic.
1. Small size: Hides easily and uses less energy
2. Large mouths- hinged extendable jaws (large teeth)
Usually will eat anything that will fit in mouth

10. Non-migrators (couch-potato fish)
Copepods and krill filter detritus and fecal pellets of epipelagic copepods.
Fishes, shrimps, and squids:
Ambush Predators
Flabby, watery, flesh instead of muscle
no swim bladder
soft, weak bones
no spines or scales

11. Blob Fish

12. Vertical Migrators Swim up at night to feed.
Well developed muscles and bones
Swim bladder for buoyancy
Tolerate temperature changes
Vertical Migration is important in transporting food into deep water
This increases food supply in mesopelagic
Non-migrators feed on migrators

13. 4. Sense Organs
tubular eyes- up or forward to increase field of vision
yellow filters can distinguish natural light from bioluminescence
lateral lines
very large eyes = more surface area to collect light

14. 5. Coloration and body shape
Countershading- black backs and silvery sides
Reduction of the silhouette
Laterally compressed bodies reduce outline

15. Bioluminescence

16. 6. Bioluminescence
Counterillumination- light production that helps animal blend in with background light filtering down from the surface
Most common color is blue and the 2nd most common color is green
Light can be from photophores, special cells, glands, ink.
Can be used in communication and to attract mates, vision, or to lure prey.

17. Oxygen Minimum Layer Gas exchange from atmosphere & photosynthesis
1,600 ft- O2 minimum layer

18. The World of Perpetual Darkness
Bathypelagic- 3, ,000 ft
Abyssopelagic-13, ,000 ft
Hadalpelagic- 20,000 – 36,000 ft
Fish have little color
bioluminescence is used for attracting prey, communication, & courtship
many are blind or have small eyes.

19. Life in the Darkness 5% of food makes it to deep water
“Couch potato” fish
Huge mouths and expandable stomachs
Anglerfish use “lure” to catch prey

20. Anglerfish

21. Sex in the Deep Hermaphrodites- both sex organs
Bioluminescence – attracts mates
Pheromones- special chemical released to attract mates
Male parasitism- anglerfish attaches to female for life

22. Living Under Pressure
Lack of swim bladder is due to high energy cost of filling it under extreme pressure.
Divides zones: deepest living fish is 27,000 ft.
Pressure effects enzymes that control metabolism

23. Life in the Benthos
Benthic animals have more time to find food and eat it.
Slow decomposition of detritus
Fecal pellets are an important source of organic matter.
Slow growth but long life (Deep-sea gigantism)

24. Hydrothermal Vents
Undersea hot springs associated with mid-ocean ridges
Discovered in 1977 by Bob Ballard
Tube worms (3.3 ft long)
Clams (12 in)
Mussels
Shrimps
Crabs
Fishes

25. Chemosynthesis
Seawater trickles down through the cracks in the crust, is heated and emerges at hydrothermal vents.
Contains hydrogen sulfide (H2S) and other minerals
Bacteria use H2S to make organic matter which is chemosynthesis
When they crystallize they form black smokers and chimneys.
Primary producer is chemosynthetic bacteria

26. Tube Worm The giant tube worm contains symbiotic bacteria
Worms supply raw materials
H2S is toxic to most animals but tube worm has special hemoglobin