The Deep

Location Mesopelagic

approx. 200m – 1000 m Dim light

The Deep Sea Below 1000m 3 zones: Bathypelagic, Abyssopelagic,

Hadopelagic

Mesopelagic Zone Main thermocline occurs here

No light, no photosynthesis

Oxygen minimum layer

Mesopelagic Organisms depend on Epipelagic

Approx. 20% of epipelagic food sinks to mesopelagic

Fewer organisms, small size

Large mouths, extendable jaws, sharp teeth due to lack of food

Adaptations of Midwater Organisms Feeding: vertical migration or filter feed on

detritus

Bioluminescence used for counterillumination

Large eyes

Non-migrators lack swim bladder

Large gills if live in O2-minimum layer

Viperfish

Lanternfish – 10 cm

Hatchetfish – 5cm Dragonfish – 35 cm

Longnose Lancetfish

– 215 cm

Vampire Squid

Deep Sea Largest habitat on earth

Conditions are very stable

Includes ocean bottom beyond the shelf

Challenger Deep Deepest part of the ocean

Approx. 11,000 m (7 miles) deep

Mariana Trench – Pacific Ocean

“Challenger” refers to British survey ship

Exploration Trieste

Manned bathyscaphe Reached 10, 919 m (35,810 ft.) in 1960

Kaiko Unmanned, Japanese research vessel 1995 reached deepest part of ocean (10,991m or

36,061 feet)

Abiotic Factors in the Deep Sea Lack of light

Pressure: 1000+ atm (14,700 psi)

Cold: 1o – 2o C

Only about 5% of food from epipelagic

Hydrothermal Vents Undersea hot water

springs

Release Hydrogen sulfide into water

Allow for chemosynthesis by bacteria

Adaptations Bioluminescence for attracting prey & mates

Many are hermaphrodites

Male parasitism

Slow metabolism, specialized enzymes

Deep Sea Amphipod

Tube worms

Swallower eel

Angler fish Devilfish