PLANET EARTH

DEEP OCEAN DWELLERS

Subject: Science/Earth Science and Biology

Ages: 10+

Length: Clip: 26 minutes; Lesson: One 45 to 55 minute class period.

This film is available from Amazon.com.

SNIPPET MENU

LEARNING OUTCOMES/OBJECTIVES

Students will be introduced to the strange and wonderful creatures that inhabit the depths of the oceans.

RATIONALE

Few people will directly experience the depths of the seas. This lesson will introduce students to this important habitat.

DESCRIPTION OF SNIPPET

This is a portion of the Planet Earth chapter entitled “Ocean Deep”.Much of the snippet is devoted to deep ocean volcanic vents. Animal species featured in the snippet include: dolphin, mackerel, shearwater, sailfish, manta ray, sea spider, sore tooth eel, Dumbo octopus, vampire squid, deep sea urchin, shrimp, monk fish, and isopods, squat lobster, giant tube worm, soft coral, and nautilus.

HELPFUL BACKGROUND

The Vampire Squid, or Vampyroteuthis infernalis, looks like something out of a science fiction movie. However its odd appearance helps the vampire squid survive in the deep ocean. It is covered in light producing organs called photophores. It can turn itself “on or off” at will through a chemical process known as bioluminescence. The squid has the ability to produce complex patterns and change the size and intensity of this light to disorient predators and attract prey. When this chemical reaction is not taking place the Vampire Squid is basically invisible in the deep dark ocean where it resides. The Vampire Squid lacks an ink sac like most squids and when threatened it ejects a cloud of sticky bioluminescent mucus. This light bombardment may last up to 10 minutes and is meant to stun predators, allowing the squid to escape into the nearby blackness.

The bodies of Vampire Squids vary in color from a pale red to jet-black depending on location and lighting. It has large fins at the top of its body that resemble giant ears. It also has the largest eyes in comparison to its body of any animal. Its eight arms are connected by webbing, making it look more like an octopus than a squid. The Vampire Squid has been found between 2,000 and 3,000 feet below sea level, in the oxygen minimum layer of the ocean, where hardly any light reaches. Because it lives in such a harsh environment, the metabolic rate of a Vampire Squid is the slowest of any deep-sea cephalopods.

The giant tube worm was completely unknown to the scientific community until hydrothermal vents were discovered on the sea floor. These vents (known as “black smokers”) pull in sea water and recirculate it. When it is finally expelled from the vent, the water is filled rich with chemicals and minerals. These chemical jets would be lethal to most life on Earth, therefore scientists were very surprised when they found entire ecosystems living off these vents. Despite the near boiling water, absence of light, and chemical soup that spills out of these vents, giant tube worms thrive on the water coming from the vents. The worms can grow up to eight feet tall and lack a mouth and digestive tract. The bacteria that live inside the giant tube worm can turn many gases into organic molecules that their host worm may feed upon. The bright red plume on the worm exchanges nutrients with the surrounding water and provides them to the bacteria, creating a very unique symbiotic relationship.

The sea spider is the largest known spider. They can grow to be one foot long.

The Dumbo octopus gets its name from two ear-like fins that extend from its head like body. They live at extreme depths between 3,000 – 4,000 meters, and are one of the rarest octopuses.

PREPARATION

Prepare for class by deciding which of the supplemental materials to present to the class. Cue the DVD to the beginning of the snippet. After playing the snippet, present the supplemental materials.

ASSIGNMENTS

Students can research and write about or make class presentations on the following little-known denizens of the deep: green globe sponge; ping-pong tree sponge; threadfin snailfish; glowing sucker octopus; giant squid; scaly dragonfish; telescope octopus; black-eyed squid; spookfish; fanfin sea devil; football fish; and the gulper eel.

SUPPLEMENTAL MATERIALS