Ion and Water Balance 7: Lake Qinghai Experiments

Question 1

what is conservation physiology
- what type of scientific discipline
- what is applied
- what does it aim to do
- what is an example of what it may involve

Answer 1

• integrative scientific discipline
• applies physiological concepts, tools, and knowledge
• aims to characterize biological diversity and its ecological implications
• involves understanding and predicting how organisms, populations, and ecosystems respond to environmental change and stressors

Question 2

Lake Qinghai qualities (2)

Answer 2

• high altitude lake
• no outflow

Question 3

what are the outcomes of Lake Qinghai having no outflow (3)

Answer 3

• solutes and water enter
• only water will leave by evaporation
• results in forever increasing salinity

Question 4

what is the osmolarity between Lake Qinghai and the plasma in fish

Answer 4

• isoosmotic

Question 5

what human-caused factor is contributing to increasing salinity of Lake Qinghai

Answer 5

• agricultural water use is dropping the water level further

Question 6

freshwater fish: passive ion/water movement (2)

Answer 6

• ion loss
• water gain

Question 7

freshwater fish: active ion/water movement (3)

Answer 7

• active Na+ and Cl- uptake at the gill
• active Na+ and Cl- uptake at the gut
• production of dilute urine in the kidneys

Question 8

marine fish: passive ion/water movement (2)

Answer 8

• ion gain
• water loss

Question 9

marine fish: active ion/water movement (4)

Answer 9

• drinking of seawater
• active Na+ and Cl- secretion at the gill
• active Na+, Cl-, and water uptake at the gut
• production of divalent ion excretion by the kidneys

Question 10

how will a stenohaline freshwater fish respond to salinity exposure (3)

Answer 10

• exhibit an acute response of rapidly activating transporters
• plasma osmolarity will continue to increase within the fish
• fish will die within a couple of days

Question 11

how will euryhaline freshwater fish response to salinity exposure (3)

Answer 11

• exhibit an acute response of rapidly activating transporters
• exhibit acclimation response where new transporters and cell differentiation is developed
• plasma osmolarity increase rapidly, before peaking and returning to a slightly higher steady state

Question 12

how do hatcheries access salmon smolt condition to determine if they are ready to be transferred to seawater (2)

Answer 12

• hatcheries transfer smolts from freshwater to seawater for 24 hours
• measure physiologically relevant parameters to access smolt status

Question 13

what are some parameters that can be measured to access salmon smolt condition (4)

Answer 13

• activity and amount of ion transporters
• plasma osmolarity/ion levels
• urine volume
• visible stress and overall activity

Question 14

how long do fish that can tolerate higher salinity exhibit recovery of osmoregulatory status

Answer 14

• 5 days after exposure to salinity

Question 15

what is osmoregulatory status following 5 days predicative of

Answer 15

• 30 days

Question 16

what major ion levels are increasing Lake Qinghai (3)

Answer 16

• Na+
• Cl-
• Mg2+

Question 17

after 24h exposure, how many fish exhibited loss of equilibrium in 13g/L salinity

Answer 17

• 13%

Question 18

after 24h exposure, how many fish exhibited loss of equilibrium in 16g/L salinity

Answer 18

• 88%

Question 19

after 24h exposure, how many fish exhibited loss of equilibrium in 20g/L salinity

Answer 19

• 100%

Question 20

after 24h exposure, how many fish exhibited mortality in 16g/L salinity

Answer 20

• 25%

Question 21

after 24h exposure, how many fish exhibited mortality in 20g/L salinity

Answer 21

• 100%

Question 22

what was parameters were monitored in the Lake Qinghai experiment (3)

Answer 22

• plasma osmolarity
• plasma ion concentrations
• gill Na+/K+ ATPase

Question 23

what information did we determine from 24h exposure to salinity: plasma osmolarity (2)

Answer 23

• there are large increases in plasma osmolarity above 9g/L
• increase or decrease by 30% can be fatal for the fish

Question 24

what information did we determine from 24h exposure to salinity: plasma ion concentrations

Answer 24

• there are large increases in plasma [Na+] and [Cl-] above 9g/L at 24h

Question 25

what information did we determine from 24h exposure to salinity: gill Na+/K+ ATPase activity

Answer 25

• no significant changes in gill Na+/K+ ATPase activity

Question 26

after 48h exposure, how many fish lost equilibrium/exhibited mortality in 13g/L salinity (2)

Answer 26

• 100%
• 13%

Question 27

after 48h exposure, how many fish lost equilibrium/exhibited mortality in >16g/L salinity (2)

Answer 27

• 100%
• 100%

Question 28

after 72h exposure, how many fish lost equilibrium/exhibited mortality in 11g/L salinity (2)

Answer 28

• 38%
• 13%

Question 29

after 72h exposure, how many fish lost equilibrium/exhibited mortality in >13g/L salinity (2)

Answer 29

• 100%
• 100%

Question 30

what information did we determine from 72h exposure to salinity: plasma osmolarity

Answer 30

• no recovery in plasma osmolarity in 11 and 13g/L salinity

Question 31

what information did we determine from 72h exposure to salinity: plasma [Cl-]

Answer 31

• in 11 and 13 g/L salinity, there was no recovery of plasma [Cl-]

Question 32

what information did we determine from 72h exposure to salinity: gill Na+/K+ ATPase activity

Answer 32

• no significant changes in gill Na+/K+ ATPase activity

Question 33

what were the conclusions from the Lake Qinghai study (2)

Answer 33

• carp appear to live on edge of their salinity tolerance
• small change in salinity above 9g/L result in large perturbations that do not appear to be compensated

Question 34

at current water diversions rates, what is the predicted lake water salinity within 50 years

Answer 34

• 11 g/L