Benthos

1
Benthos

• Benthos are creatures that live on, near, or in
  the bottom of the ocean floor.
• There is a huge variety of benthos and what you
  find depends on what the bottom is made of.

2
Benthos, contd

• Seaweeds are primary producers found attached to
  rocky bottoms. There are red, brown and green
  seaweeds.
• Some seaweeds have air bladders so that they can
  float toward the sunlight.
• Several species are harvested to eat or extract
  seaweed products (algin, carrageenan) which are
  used as thickening agents in foods such as ice
  cream, pudding, chocolate milk

3
Benthos, contd

• Creatures that attach to the bottom are
  barnacles, mussels, periwinkles
• Creatures that live near the bottom are crabs,
  lobsters, sea stars, sea urchins, and several
  species of fish including skates and flounder.
• Creatures that burrow in the bottom are clams and
  worms

4
Common Benthos
5
Benthos, contd

• Benthos in the intertidal zone must cope with an
  incredible range of conditions - temperature,
  salinity, humidity
• Many of these creatures have some means of
  avoiding dessication (drying out). Periwinkles
  and barnacles can close off their shells to
  prevent water loss, clams burrow into the mud,
  and seaweeds have a waxy coating to resist drying.

6
Deep Sea Benthos

• Challenges of living in the deep sea are
• Low availability of food
• No light, no photosynthesis
• Falling remains of dead organisms
• Low (0-2C), constant temperature
• High pressure (400-500 times atmospheric)

7
Deep Sea Benthos, contd

• Characteristics of many deep sea benthos are
• low activity levels
• slow growth long lives
• low population densities but high species
  diversity

8
Deep Sea Benthos, contd

• Some common adaptations are
• opportunistic deposit feeders
• high water content in their bodies to deal with
  the pressure
• bioluminescence to attract food and mates
• large eyes and big mouths

9
Deep Sea Benthos
Gulper Eel
Viperfish
Anglerfish
Anglerfish
10
Deep Sea Benthos
Fangtooth
11
Hydrothermal Vents

• Areas where geologic-heated water (400-600ºC) and
  gases are released from the ocean floor
• Basis of life around deep sea hydrothermal vents
  is chemosynthesis rather than photosynthesis.
• chemical energy rather than sunlight
• bacteria rather than plants or algae are the
  primary producers.

12
Hydrothermal Vent Benthos
Clams
Tube Worms
13
Activity Design a Deep-Sea Benthos

• In groups of 3, using the challenges of deep sea
  living of deep-sea benthos as a guide, design a
  deep-sea benthic organism that would make mother
  nature jealous.
• Step 1 In groups of 3 (I will choose groups),
  brainstorm characteristics your organism will
  have (at least 5).
• Step 2 Draw a picture (on chart paper colour
  is required) of what the organism will look like
  paying particular attention to LABEL its
  adaptations.
• Step 3 Present the organism to the class and
  discuss each adaptation you have given it with
  regard to its significance.

14
Presentations

• What have you come up with?

15
Oceans Log

• What adaptations did you give your deep-sea
  benthos? What is the significance of each
  adaptation?

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Exit Slip on a separate sheet

• What are 4 common adaptations to deep-sea benthos?