Comparative Anatomy and Physiology of Animals
Lecture 10 Diving Physiology 11/11/20
Physiological factors affecting diving by air-breathing vertebrates
- Temperature’s generally colder.
- Pressure of water increases.
- Lack of access to oxygen.
- Most physiological responses relate to oxygen supply during diving.
- Diving research in labs has often yielded different results than voluntary diving in wild.
Deep sea living in fish
- Density of whole fish is greater than water.
- Need mechanisms to retain buoyancy or they would sink – hydrofoil fins in sharks or low-
density lipids.
- Swim bladder (gas-filled).
- Fish with swim bladders found at 7000m deep.
- Deep-sea fish rarely survive after being pulled to the surface
- Various adaptions to metabolism include metabolic depression and osmolytes that increase
cell volume- maintain normal enzyme function.
- Lipids have more polyunsaturated fats to maintain membrane fluidity.
Swim bladder function
- Filling swim bladder is achieved by the Root effect, i.e. blood acidification releases oxygen
from haemoglobin.
- At high pressure, the swim bladder wall has to resist the steep diffusion gradient for oxygen.
- Wall is lined with guanine crystals and gas-impermeable epithelium that renders it
impermeable to gas.
- Need to partition O2 in swim bladder may limit vertical movement through the water
column.
Galapagos marine iguana (Amblyrhynchus cristatus)
- Dives to eat marine algae in cold water.
- 5-10 minutes to 1.5-5m.
- Some dives recorded at 30 minutes down to 12m.
- Relies on anaerobic respiration and lactate tolerance.
- Physiology comparable to terrestrial iguanas.
- Enforced prolonged dives are physiologically stressful because of lactate accumulation.
- Representative of a terrestrial line that was pre-adapted for evolving diving habit.
Diving abilities- mammals and birds
- Modern remote sensing equipment allows for recording of diving in mammals and birds.
- Different groups of mammals and birds dive for varying durations and to different depths.
Sperm whale Penguin
Lecture 10 Diving Physiology 11/11/20
Physiological factors affecting diving by air-breathing vertebrates
- Temperature’s generally colder.
- Pressure of water increases.
- Lack of access to oxygen.
- Most physiological responses relate to oxygen supply during diving.
- Diving research in labs has often yielded different results than voluntary diving in wild.
Deep sea living in fish
- Density of whole fish is greater than water.
- Need mechanisms to retain buoyancy or they would sink – hydrofoil fins in sharks or low-
density lipids.
- Swim bladder (gas-filled).
- Fish with swim bladders found at 7000m deep.
- Deep-sea fish rarely survive after being pulled to the surface
- Various adaptions to metabolism include metabolic depression and osmolytes that increase
cell volume- maintain normal enzyme function.
- Lipids have more polyunsaturated fats to maintain membrane fluidity.
Swim bladder function
- Filling swim bladder is achieved by the Root effect, i.e. blood acidification releases oxygen
from haemoglobin.
- At high pressure, the swim bladder wall has to resist the steep diffusion gradient for oxygen.
- Wall is lined with guanine crystals and gas-impermeable epithelium that renders it
impermeable to gas.
- Need to partition O2 in swim bladder may limit vertical movement through the water
column.
Galapagos marine iguana (Amblyrhynchus cristatus)
- Dives to eat marine algae in cold water.
- 5-10 minutes to 1.5-5m.
- Some dives recorded at 30 minutes down to 12m.
- Relies on anaerobic respiration and lactate tolerance.
- Physiology comparable to terrestrial iguanas.
- Enforced prolonged dives are physiologically stressful because of lactate accumulation.
- Representative of a terrestrial line that was pre-adapted for evolving diving habit.
Diving abilities- mammals and birds
- Modern remote sensing equipment allows for recording of diving in mammals and birds.
- Different groups of mammals and birds dive for varying durations and to different depths.
Sperm whale Penguin
