Chapter 6: climate change and oceans

Question 1

concentration of deissolved salts in water

Answer 1

• NaCl (sodium chloride)
• magnesium
• calsium
• potasium
• sulfate

Question 2

the average salinity of ocean is

Answer 2

35 ppt (parts per thousand)

35 grams of salt dissolved in 1000g of sea water

Question 3

properties of water that are changed by

Answer 3

having salt in it

• salt makes sea water more dense than fresh water
• salty water needs to be colder than fresh water before it freezes
  
  • freezing point of fresh water is 0c
  • freezing point of sea water is -2 c

Question 4

ocean salinity change due to climate change:

impacts on anthropogenic CC on ocean

Answer 4

• rise in sst
• sea level rise
• acidification
• salinity variations (indirect impact of CC)

Question 5

cause of changed salinity

Answer 5

• evaporation (inc)
• precipitation (dec)
• fresh water from river discharge (dec)
• ocean currents
  
  • from less saline oceans (dec)
  • from saline oceans (inc)

Question 6

global salinity is effected by

Answer 6

• hydrological cycle
  
  • evaporation rates
  • precipitation rates
  • river discharge
• ocean currents

climate change will result in stronger hydrological cycle

Question 7

how global warming effects salinity

Answer 7

• global warming
  
  • stronger hydrological cycle
    
    • arid regions
      
      • become dryer
        
        • more evaporation
          
          • salinity increase
    • wet regions
      
      • become wetter
        
        • more precipitation
          
          • salinity decrease

Question 8

ocean acidification

Answer 8

oceans take up CO2 from the atmosphere (absorb 1/3 of the atmospheric CO2) since the industrial revolution

• reduce global warming
• cause changes in ocean chemistry (carbonate chemistry)
  
  • ocean acidification
  • DIC (dissolved inorganic carbons)

Question 9

Carbonate chemistry of sea water

Answer 9

• atmospheric CO2 dissolve in sea water
  
  • aquous CO2
    
    • carbonic acid
      
      • rapidly dissociate to produce photons and
      • bicarbonate ionns
        
        • dissociate into
          
          • carbonate ions and photons

Question 10

• atmospheric CO2 dissolve in sea water
  
  • aquous CO2
    
    • carbonic acid

Answer 10

CO₂ (aq) + H₂O –> H₂CO₃

Question 11

carbonic acid

• rapidly dissociate to produce photons and
• bicarbonate ionns

Answer 11

H₂CO₃ <—> HCO₃^- + H⁺

(carbonic acid) <—–> (bicarbonate ions) + (photons)

GIVE RISE TO PHOTONS

Question 12

• bicarbonate ionns
  
  • dissociate into
    
    • carbonate ions and photons

Answer 12

HCO₃^- <——> CO₃^2- + H⁺

(bicarbonate ions) <—–> carbonate ions + photons

GIVE RISE TO PHOTONS

Question 13

PH is defined as

Answer 13

PH= -log₁₀ [H⁺]

the increase in H+ photons will reduce the PH value of the sea water making it more acidic when (PH value <7)

Question 14

compare the PH values from the past and now

Answer 14

over the past 300 million years = 8.2

current value of PH = 8.1

Question 15

for a reduction of 0.1 in PH value, what is the corresponding change in [H+] photons

Answer 15

H+ = antilog10 (PH)

H+= 10^8.1

H+ 8.1 = 125892541.2

H+ 8.2= 158480319.2

( (H8.2 - H8.1)/H8.1 )x 100 = 25.9% (increasing acidity)

this is becaue PH sscale is not linear

Question 16

the total DIC in sea water is defined as

Answer 16

DIC = [CO₂] + [HCO₃^-] + [CO₃ ^2-]

carbon dioxide + bicarbonate + carbonate

Question 17

distribution of DIC

Answer 17

the distribution between the three species varies between PH of sea water

Question 18

for PH = 8.1

Answer 18

[CO₂] : [HCO₃^-] : [CO₃^2-]

1 : 100 : 10

Question 19

as more CO2 is added to sea water

Answer 19

• PH decreases
• the balance between the three carbonate species also change
  
  • CO₂ (aq) and HCO₃^- increase
  • CO₃^2- decrease

(this is an indication of anthropogenic ocean acidification

Question 20

projected ocean acidification

Answer 20

• anthropogenic CO2 emissions cause
  
  • warming of oceans
    
    • 2 to 4 c by the end of 21st century
  • increase in ocean carbon content
    
    • ocean acidification
      
      • reduction in marine carbonate
    • reduction of dissolved neutrients in the surface

Question 21

sea level rise is caused by

Answer 21

• thermal expansion
• additional water flow from ice melting

Question 22

sea level rise consequence

Answer 22

due to increase of sea level rise

• low lying areas will have more frequent flooding
• very low lying areas could be submerged campletely
• wil change coastal wet lands and harm coastal ecosystems
  
  • mongroov forests
  • coral refs

Question 23

sea level rise projection

Answer 23

• over the past 100 years average sea level rise in 7 inches
• by the end of 21st century, 7-23 inches additional rise expected