Chapter 16

The Ocean Depths

Click here for introduction video!!

Life in the mesopelagic and deep sea is linked to plankton and light

intensity in the water.

Amount of nutrients at different depths is

controlled by photosynthesis, respiration, and the sinking of

organic particles.

Nutrients are recycled but sink!

Deep water originates at the cold surface at the poles. Cold water sinks and spreads out along the bottom.

The deep currents are part of the great ocean conveyor. Small variations in the conveyor produce big changes in

weather patterns around the world (El Nino). Large changes create ice ages.

Mesopelagic Crustaceans

Photophores

Specialized light structures that make “living light” or bioluminescence.

click here for v

ideo

Typical Mesopelagic Fish

Rectangular midwater trawls used to collect mesopelagic organisms. Net has remote control to

open only at certain depths.

As more shallow fish are

over fished other deeper fish like this

black scabbord fish are being

caught.

Adaptations of Vertical migrators like the Lanternfish on left and non-migrators like dragonfish on right.

1. Well developed muscles and bones

2. Swim bladder of air or fat

3. Withstand extreme temperature changes

Large hinged jaw that can accommodate large prey

Many non-migrators like this Rattrap Fish eat the more muscular migrators because they have more protein!

Tubular eyes like this midwater bristlemouth fish, with acute (great) upward vision.

Check out this video of a weird fish with

tubular eyes

•Midwater predators rely on sight.

•Midwater prey cannot afford energy for swimming fast, spines, or scales so they are…

•Camouflaged with countershading (dark on top, light bottom or sides)

•Transparent or see through

• Silhouetted (bioluminescence on bottom) With blue-green light they control! Cool!

Photophores on lower or ventral surface makes the silhouettes hard to see when they are viewed through water.

Living light is used for…

1) Counterillumination to mask silhouette

2) Escape from Predators with confusing light

3) Attract or see prey

4) Communication and Courtship

Typical Characteristics of deep-sea pelagic fish

Compare mid-water and deep-water fish

- Which has the smaller muscles, fewer light organs, smaller brain and respiratory system and why?

Tremendous pressure of 1,000 atmospheres or 14,700 psi

1. Tough to visit and bring fish back alive

2. Metabolism affected by pressure

3. Molecules are adapted to allow enzymes to work under extreme pressures.

Finding mates is a problem in the dark

So they use…

1. Bioluminescence

2. Chemical signals

3. Hermaphroditism

4. Male Parasitism

Reduced eyes or are completely blind (Live in complete darkness)

Huge mouths to eat prey larger than themselves (Scarce food -less than 5% from higher waters)

No vertical migrations to richer surface waters(Flabby muscles, weak skeletons, no scales, and poorly

developed respiratory, circulatory, and nervous systems)

Slow Pace (Save Energy)

Low Temp and High Pressure(slow pace)

Live Long and Large(up to 100 years)

Produce fewer larger eggs(a lot of food for larva)

Dominated by Deposit Feeders(eat biological snow)

Deep-sea Hydrothermal vents harbor rich

communities.

The primary production that supports these

communities comes from microbial chemosynthesis,

not photosynthesis.

Tubeworms have symbiotic bacteria in them that take the hydrogen sulfide or methane from vents, or dead bodies and

make energy rich molecules to feed the worms!

Inquiring minds want to

know….

How Do Light Sticks Work?

What is Bioluminescence?

How does Bioluminescence work?

A light stick consists of a glass vial, containing one chemical solution, housed inside a larger plastic vial, containing another solution.

When you bend the plastic vial, the glass vial breaks, the two solutions flow together, and the resulting chemical reaction causes a fluorescent dye to emit light.

Bioluminescence Lab

Glowing Fishing Lures

How Living Light Works

Strike Bright Fishing Lures Video

Strike Bright Lure Commercial