Deep-Sea Communities
OCN 201 Biology Lecture 13 Deep Sea • Physical Conditions •- Cold •- High Pressure •- Dark • Animals (and food) are sparse Deep Scattering Layer Vertical Migration by Plankton
Sonar
• se Food for the Deep • 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.
Adaptations in the Deep Sea - Clear bodies or reflective sides and counterillumination (disphotic zone)
- Red or Black bodies (aphotic zone)
- Oversize mouths
- Specialized eyes (or degenerated)
- Bioluminescence Red or Black Bodies
Red looks black in blue light Architeuthis - the giant squid
Vampyroteuthis infernalis What does this thing eat?
marine snow?! Big Mouths!
Bioluminescence Some fish that use bioluminescence Light produced by a biochemical reaction
USED FOR: • Counterillumination (camouflage) • Communication (finding mates) • Lures (enticing prey) • Searchlights (illuminate prey) • Decoy or surprise (escape from predator) Deep Sea Floor (about 3 km deep)
✦ Low Numbers (not much food)
✦ High Diversity (resource limited)
✦ Long Lives (low metabolic rates)
✦ Many deposit feeders and scavengers (about 4.8 km deep) ✦ Epifauna - urchins, brittle stars, crinoids, etc
✦ Infauna - crustaceans, worms, etc.
Tripod Fish Brittle Stars Hydrothermal Vents & Cold Seeps • Specialized benthic habitats • Oases with very high abundance of organisms (Why?) • Primary Production by Chemosynthesis! Hydrothermal Vents Cold Seeps - hydrogen sulfide (H S) H S 2 2 - methane (CH ) 4 Photo- vs Chemosynthesis
Light Energy
6CO2 + 6H2O C6H12O6 + 6O2
O2 + H2S Chemical Energy
6CO2 + 6H2O C6H12O6 + 6H2SO4 The Deep Sea - Summary • 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