OCEAN INFORMATION

DEPTH ZONES

Epipelagic zone “sunlight zone”1st 200 metersalmost all visible light occurs here

Mesopelagic zone “twilight zone”200-1000 metersbioluminescent organismstremendous biological diversity

Bathopelagic zone “midnight zone”1000-4000 metersno light, except made by creatures

Abissopelagic zone4000-6000 metersvery little life, mostly invertebrates

Hadalpelagic zone6000+ meterstube worms

http://www.seasky.org/deep-sea/ocean-layers.html

Coral Reefs

How a reef develops1. Polyps release egg & sperm which makes larvae2. Larvae settle on hard surfaces & develop into coral polyps3. Polyps have zooxanthellae algae living in them that provides energy4. Coral polyp secretes calcium carbonate, which builds the reef

Coral ReefsCoral polyps are colonial animals

(many of them grow together) that are attached by a thin membrane

There are many types of corals and most grow very slowly (2.5 cm/yr)

Types of Corals

Hard or stony corals:made with calcium carbonate the polyp secretes

can form massive stony structures examples: brain, staghorn, star, finger corals

Hard Coral

Brain Coral

Staghorn Coral

Star Coral

Finger Coral

Staghorn Coral

Types of Corals

Soft corals:flexible due to fibrous protein

sway back and forth with water movement

examples: sea fan, sea whip, sea plume

Sea Fan

Sea Whip

Sea Plume

Locations & Conditions

Locations: tropical regions of world between 30 degrees north & south of equator

Conditions: warm & clear water, shallow water, plenty of sunlight

Coral bleaching: algae are expelled & coral polyps die

Types of Reefs

Fringing – runs parallel to the shore a few kilometers offshore; found around Florida Keys & Caribbean

Barrier – grows farther offshore; Great Barrier Reef in Australia & Bahamas Barrier Reef

Atoll –circle of reef with a lagoon in the center; once had a volcanic island in the center

Fringing Reef

Barrier Reef

Atoll Reef

Variety on a Reef

Many types of corals live together, each with its own shape

Fish and other creatures live on or near the reef – crevices offer shelter & homes

Cleaner stations for fish to have parasites removed

Avoiding Detection by Predators

Hide in reef or sandy bottomCamouflage – coloration or blending

in with similar shapeSwimming in large groups, or schoolsColoration – bright colors to identify

members of own species; used to confuse predators

How Coral Reef is Harmed

Parrotfish eat the coral to get its algaeCrown-of-thorns sea star eats polypsChanges in land habitat – siltCoastal development & dredgingFertilizer & pollution like oil slicks,

pesticides, garbageOverfishing & overcollectingBoat anchors