Lecture 12 - Physical variables affecting deep sea animals

Question 1

Greatest temp difference is wher

Answer 1

Top 1000 m

Question 2

Pressure varies how with depth

Answer 2

Linearly increases with depth everywhere, no special spots

Question 3

Where can you expect higher than normal temps in the deep sea

Answer 3

bottom of basins with shallow sills - Sulu Sea, Mediterranean

Question 4

Reason for death of animals during recovery

Answer 4

1. Physical damage to body by capture gear
2. Embolism from swimbladder expansion
3. Water balance in fish - damage to skin imposes load on kidneys due to salt gain and water loss
4. Toxic fatigue - anaerobic metabolism in escape responses causes ph to as low as 6.5-7
5. Temperature
6. Asphyxiation
7. Oxygen toxicity (higher O2 at surface)

Question 5

How does pressure increase the density of materials?

Answer 5

It decreases the space between molecules

Question 6

What sites are affected by pressure changes?

Answer 6

Gas spaces - embolisms
Lipids - adapt with high concentrations of unsaturated fatty acids
Enzymatic reactions - acts during catalyst activated complex to change rate, adapt to reduce sensitivity

Question 7

What occurs when shallow animals are subjected to higher pressures?

Answer 7

Initially no response
Phase of stimulated activity at higher pressures
Phase of increasingly deranged activity and muscle tetany
Finally, death

Question 8

Shallow species show pressure tolerance _______ of their environmental exposure

Answer 8

far in excess

Question 9

Require pressure to grow

Answer 9

Barophilic (or piezophilic) Bacteria

Animals from depths greater than 2500 m

Question 10

Decompression can result in what?

Answer 10

Damage to DNA

Question 11

Pressure effects

Answer 11

On materials

• Compression of solutions
• Protein volume
• Affects chemical equilibria

On membrane lipids
-Changes phases and volume of lipids affecting permeability

Question 12

Adaptation to Pressure affecting volume

Answer 12

reduction of volume change to activate complex

-higher E cost, poorly adapted to low T

Question 13

Pressure adapted enzymes tend to be what?

Answer 13

1. Have low volume changes to activate complex
2. Have enzyme/substrate affinity relatively unaffected by pressure
3. Higher activation E cost
4. Lower catatlytic efficiency

-adapted at the cost of being poorly adapted to low T

Question 14

What is TMAO?

Answer 14

Strong protein stabilizer

Question 15

TMAO ______ with depth.

Answer 15

increases

Question 16

TMAO ______ with depth in body fish and inverts

Answer 16

rises

Question 17

Urea:TMAO ratio _______ with depth in Elasmobranchs

Answer 17

decreases

Question 18

T and P _________ each other.

Answer 18

counteract

-survival improved at higher P if T is higher and lower P is T is lower

Question 19

For enzymes, P and T effects would be _____

Answer 19

additive

• affinity decreases at high P and high T
• affinity increases at low P and low T

Question 20

For lipids, P and T effects would be _______

Answer 20

counteractive

-High T -> fluid while high P -> gel