Post on 18-Jan-2018
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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.
Benthos, cont’d• 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
Benthos, cont’d• 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
Common Benthos
Benthos, cont’d• 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.
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 (0-2°C), constant temperature• High pressure (400-500 times
atmospheric)
Deep Sea Benthos, cont’d
• Characteristics of many deep sea benthos are:– low activity levels– slow growth; long lives– low population densities but high
species diversity
Deep Sea Benthos, cont’d
• 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
Deep Sea Benthos
Gulper Eel
Anglerfish
Anglerfish
Viperfish
Deep Sea BenthosFangtooth
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.
Hydrothermal Vent Benthos
Clams
Tube Worms