OCN 201 Biology Lecture 13
Deep-Sea Communities
• Physical Conditions•- Cold•- High Pressure•- Dark
• Animals (and food) are sparse
Deep Sea
• se
Deep Scattering Layer
Sonar
Vertical Migration by Plankton
• Detritus from the surface ocean food web falls down to the deep sea
• This falling detrital material is marine snow, fecal pellets and occasional dead animals
• Marine Snow consists of bits of aggregates of algae, discarded larvacean houses, microorganisms, etc.
Food for the Deep
- Clear bodies or reflective sides and counterillumination (disphotic zone)
- Red or Black bodies (aphotic zone)
- Oversize mouths
- Specialized eyes (or degenerated)
- Bioluminescence
Adaptations in the Deep Sea
Red or Black Bodies
Red looks black in blue light
Vampyroteuthis infernalis
Architeuthis - the giant squid
What does thisthing eat?
marine snow?!
Big Mouths!
• Counterillumination (camouflage)
• Communication (finding mates)
• Lures (enticing prey)
• Searchlights (illuminate prey)
• Decoy or surprise (escape from predator)
Bioluminescence Light produced by a biochemical reaction
USED FOR:
Some fish that use bioluminescence
✦ Low Numbers (not much food)
✦ High Diversity (resource limited)
✦ Long Lives (low metabolic rates)
✦ Many deposit feeders and scavengers
✦ Epifauna - urchins, brittle stars, crinoids, etc
✦ Infauna - crustaceans, worms, etc.
Deep Sea Floor(about 3 km deep)
(about 4.8 km deep)
Tripod FishBrittle Stars
Hydrothermal Vents & Cold Seeps
H2S
• Specialized benthic habitats
• Oases with very high abundance of organisms (Why?)
• Primary Production by Chemosynthesis!
Cold SeepsHydrothermal Vents- hydrogen sulfide (H
2S)
- methane (CH4)
Photo- vs Chemosynthesis
6CO2 6H2O+ C6H12O6 6O2+
LightEnergy
6CO2 6H2O+ C6H12O6 6H2SO4+
+O2 H2S Chemical Energy
• Physical Conditions•- Cold•- High Pressure•- Dark
• Animals (and food) are sparse
• Many special adaptations•- Clear, or at > 700 m: many are red or black•- Oversize mouths•- Bioluminescence•- Reduced silhouette•- Specialized eyes (or degenerated)
• Hydrothermal Vents and seeps• A second source of Primary Production in the sea
• Only bacteria can do it
• Animals with autotrophic endosymbionts result in rich oases in a food desert — just like coral reefs in tropical seas! — but the symbionts at vents are chemoautotrohs instead of photoautotrophs
The Deep Sea - Summary