The Deep Sea
Mesopelagic
Deep Sea 1

Division of the Deep Sea
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Mesopelagic
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Effective light penetration - 1,000 m.
Bathypelagic
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1,000 - 4,000 m.
Abyssopelagic
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4,000 - 6,000 m.
Hadopelagic
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6,000 m. or more
Deep Sea 2

Sampling Considerations
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The depth of the habitat creates a logistical problem
Animals arrive dead due to the drastic pressure change
These problems lead to the possibility of inaccurate conclusions on population size
Deep Sea 4

Submersibles and ROV’s
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Submersibles and Remotely
Operated Vehicles (ROV) are the ideal method for sampling the deep sea
Deep Sea
Visit the Alvin website
Alvin submersible. Photo source: WHOI
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Submersibles and ROV’s
Deep Sea
Jason II Photo source:
WHOI
Visit the Jason II website
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The Mesopelagic
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A world of twilight which cannot support photosynthesis
Animals that live in the mesopelagic must deal with the Oxygen Minimum
Layer
Deep Sea 7

Mesopelagic Fauna
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Krill and copepods dominate
Arrow worms, squid, jellyfishes and other invertebrates are important predators
Most of the animals that live in the mesopelagic have light organs or photophores
Deep Sea 8

The Deep Scattering Layer
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Many mesopelagic animals also migrate to the surface waters at night to eat
Deep Sea 9

Deep Sea
Mesopelagic Fish
10

Bioluminescence
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Definition - _____________________________
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Bioluminescence occurs most notably in the mesopelagic
Light producing organs are called ___________
What are photophores used for?
Deep Sea 11

The Deep Sea
The world of complete darkness
Deep Sea 12

Deep Sea
Environmental conditions
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Light
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Most of the deep sea is aphotic
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Due to the dependence on the surface waters for nutrients, there is very little life below the mesopelagic
13

Pressure
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Until recently, physiology on these animals was very difficult since bringing them to the surface usually results in mortality
Deep Sea 14

Temperature
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At 1000 m temperature is 4-6  C
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With an increase in depth temperature changes very little
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There is no other habitat on the planet which exhibits such a stable temperature
Deep Sea 15

Adaptations of Deep Sea
Organisms
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Food is a limiting factor!
How do deep sea organisms ensure food capture?
Deep Sea 16

Deep Sea
Adaptations of Deep Sea
Organisms
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Deep Sea
Hinged Head
18

You Have
Beautiful
Eyes

Reproduction
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In a sparsely populated world mates are difficult to find
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Most deep sea fishes are _____________ and attract each other through bioluminescence
Deep Sea 20

Invertebrates
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Invertebrates are purple (jellyfish) or red (copepods)
Many invertebrates are transparent
Deep Sea 21

Abyssal Gigantism
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The phenomena where some species attain large sizes not seen any where else
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Isopod – sea roach can reach 40 – 50 cm.
( Bathynomeus giganteus )
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Amphipod – 15 cm.
( Alicella gigantca )
Deep Sea 22

Hydrothermal Vents
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Animals are found concentrated around hot water geysers
Deep Sea 23

Chemosynthetic Bacteria
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Using sulfides bacteria create organic compounds
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Most animals have symbiotic relationships with the chemosynthetic bacteria
Deep Sea 24

Vestimentiferan worm
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These worms contain 10 billion grams of microbes per 1 gram of tissue!