Consequences of water breathing

Question 1

What are the similarities between fish and turtles (water breather vs air)

Answer 1

• both poikilothermic
• both aquatic
• both relatively low MR

Question 2

[O2] in water is ____ ____ compared to air. This means:

Answer 2

• very low
• greater ventilatory flow is required to deliver O2 to gills

Question 3

Why is there greater ventilatory costs for water breathers?

Answer 3

• greater density and viscosity of water = more effort to move through water and breathe

Question 4

Water breathers have lower O2 consumption per ___ ___ in water compared to air breathers. What does this do?

Answer 4

• unit mass
• limits metabolic scope + ability to increase O2 consumption (performance limited)

Question 5

PCO2 in water breathers is ___. This means:

Answer 5

• low
• readily excrete CO2

Question 6

Why do water breathers readily excrete CO2?

Answer 6

• greater ventilatory flow across gills (O2 needs over demand)
• higher CO2 solubility in water (easy to excrete)

Question 7

What is the primary stimulus for respiration in air breathers?

Answer 7

• CO2

Question 8

What is the primary stimulus for respiration in fish?

Answer 8

O2

Question 9

How much dissolved oxygen is in air?

Answer 9

• 210Lml/L

Question 10

How much dissolved oxygen is in water?

Answer 10

• 6ml/L

Question 11

What does the difference in dissolved oxygen in air and water mean?

Answer 11

• 30x more water to ventilate in water than in air