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Chapter 11
The Deep Sea Floor
I.
Living conditions on the deep sea floor
A. Marine sediments (figure 11.3, page 337)
1. Terrigenous sediments and nodules
2. Oozes (silicaceous and calcareous)
3. Red clays
4. Deposition rate
B. Other conditions (table 11.1, page 337)
1. Temperature
2. Pressure
3. Salinity
4. Dissolved oxygen
C. The abyssal plain vs. trenches
II. Oxygen and food in the deep sea
A. Oxygen
1. Where the oxygen comes from
2. How it gets there
3. Why oxygen is depleted at intermediate depths
4. Why oxygen concentrations increase below that
5. What happens under stagnant conditions
B. Food
1. Where food comes from
2. What form are they in? (small particles, blobs, fecal pellets)
3. How much nutritional content is left?
4. What happens to small particles?
5. What happens to large, rapidly-sinking particles?
III. Life on the abyssal plain
A. What does the abyssal plain look like?
B. Dominant species (echinoderms, polychaete worms, sea spiders, isopods, amphipods)
C. Pogonophorans
D. Species diversity (figure 11.8, page 341)
1. Explaining the relatively high species diversity
a. Large areas, few barriers
b. Small-scale variation in food supply and physical conditions
2. Feeding types
a. Deposit feeders
b. Generalist scavenger-predators
c. Absorptive feeders
d. Croppers
E. Reproduction
IV. Vent and seep communities
A. Where they are found (figure 11.11, page 343)
B. Hydrothermal vent communities
1. Properties of water at vents
a. Temperature
b. pH
c. Chemical composition
d. Oxygen
2. White smokers and black smokers
3. Thermophilic species
a. Bacteria and the importance of bacterial chemosynthesis
b. Clams and mussels
c. Worms
d. Crabs
4. Adaptations of thermophilic species
a. Hemoglobin and hemocyanin
b. Insensitivity of blood pigments to high temperatures
C. Larval dispersal of vent species
1. Conflicting needs: species survival, colonization of new areas, reduction of competition
2. Passive drift vs. inquilinism vs. plume drifting
D. Cold seep communities
E. Methane seep communities