THE DEEP

Aphotic Zone (Deep Pelagic)

• Below 1000m (3280 ft)

• Explored < 1%

Pressure

• At 1000 m is 100X greater than sea level pressure

• Surface organisms would be crushed

After nearly 5,000 m down

Adaptations

• Fluid is almost incompressible

• Fluid in animals’ bodies match surrounding water

• Dive 1000m, over an hour • Lungs collapse flat

Cold 1 - 2 C (34-37 F)

• Body temp close to water

• Metabolism slow

• Reproduce less and later

• Live longer

Food is Scarce

• 5% of food produced in the euphotic zone

• No migrators

• Need to conserve energy…How?

Be Blobby

“Blobby”

• Flabby, watery flesh

• Weak skeletons

• No scales

• No swim bladder

• Sit and float

Be small

• Many angler fish are 10 cm or less!

• Largest is 1m (3 ft) and 9 kg (20 lb.)

Eat anything!

Huge Mouths and expandable stomachs

• Swallower Eel

Use vibrations to find food

• Hairy angler has sensitive antennae

• Use lateral line to sense vibrations

Go fishing!

Dragonfish Anglerfish

It’s Dark!

• Small eyes

• Black, red color

• Bioluminescence:

• --To attract prey or find mate

• --Not for counterlighting

Sex in the Dark

• 1) Use Bioluminescence to ID species

• 2) Be a hermaphrodite

• 3) Release chemicals to find mate

Sex in the Dark

• 4) Attach yourself to your mate!

• Males Goal: Search for female

• Have muscular bodies, large eyes, and organ to “smell”

Sex in the Dark

• Male bites female and they become fused

• Male provides sperm to female

World’s Smallest Fish

• Male, sexually mature is 6.2 mm (less than a ¼ inch)

• Female is 46 mm (1.8 inches)

Disphotic Zone (Mesopelagic)

• 150 m depth

• Not enough light for photosynthesis

• 10-20% food from surface is available

Size and Shape

• Small 10 to 15 cm• Long flattened body

Lantern fish

Large eyes

• Hatchetfish• Light sensitive for

dim light

WinteriaLook up at surface and spot silhouettes of preyTwo fields of vision

Mouths

• Large, hinged extendible jaws

• Needle-like teeth

• Eat anything

Sabertooth Viperfish

• Only a couple of inches long

Color

• Black, or black with silver sides

• Counterillumination/counterlighting

Other things besides fish may be transparent

Bioluminescence

Bioluminescence

• Photophores for camouflage

• Attract prey

• Attract mates

• Defense

Migrators vs. Nonmigrators

• Swim up to surface to eat at night

• Well-developed muscles and bone

• Swim bladder

• Sit and wait• Less

muscle,flabby • No swim bladder • Weak bones

Lantern fish Migrators

• Largest migration of life on earth• 1700 m to 100 m (3 hour trip)• Create a false bottom on sonar

Deep-Sea Floor

rabbit fish and tripod fish

Deep sea fish

Rat tail fish and hagfish

Deep sea fish

• Cruise the bottom

• Fecal pellets and the occasional whale for food

• Larger, long bodies, strong muscles, small eyes

• Not much bioluminescence

• Dark brown, black

Hydrothermal Vents

Mid-Ocean Ridge SystemOceanic plates are pulling apart

Hydrothermal Vents

• At mid-ocean ridges

• Seawater seeps through cracks

• Gets super heated

• Forced back up through crust

Black Smokers

• Warm 50-68 degrees F

• Hot! 662 degrees F• Heated water

dissolves minerals• When it cools,

minerals deposit around vents

Hydrogen sulfide

• 1. Energy-rich molecule

• 2. Toxic to most organisms

Bacteria - Chemosynthesis

• Basis of food chain

• Use hydrogen sulfide for energy

Bacteria as producers

• 1. Live inside animals– Symbiotic – Bacteria get hydrogen sulfide, animals get

food

Pompeii worm

Pompeii Worm

Tube Worm

Up to 2 m tallRiftia tube worm

Bacteria as producers

2. Filter feeders (mussels, clams)

3. Eaten directly (shrimp scrape bacteria off chimneys)

Mussels (filter feed) and eel

Submersible

Mussels

Vents don’t last

• Organisms get “cooked”

• 20 - 75 years• Organisms get very

large

Cold Seeps

Cold Seeps

• At continental margins

• Hydrogen sulfide and methane for chemosynthesis

• Grow slower, old and stable

Cold Seeps

Whale carcasses

• Decomposing - hydrogen sulfide

• Supports chemosynthetic bacteria

• Link to vents??

• One about every 25 Km

Worms at whale carcass

• No eyes• No mouth,

stomach• Green “roots”

grow into bone and digest fat and oils with the help of bacteria

Worms at whale carcass

• Females, 2-7 cm with large egg sac

• Microscopic male worms living inside the females

• Eggs/larvae float until they find another whale

• Related to tube worms at hydrothermal vents

Whale bone with worms

• Females, 2-7 cm with large egg sac

• Microscopic male worms living inside the females

• Eggs/larvae float until they find another whale

• Related to tube worms at hydrothermal vents

www.mbari.org/news/news_releases/2004/whalefall.html