Climate change: biogeochemical

Question 1

ocean as a carbon sink

Answer 1

3 main reservoirs for CO2
50% atm
30% ocean
20% land
factors contributing to CO2 uptake by ocean:
1) temp affects solubility
2) wind speed affects air-sea interface
3) rate of removal of anthro CO2 from surface decreases surface conc

Question 2

distribution of anthro CO2 in ocean

Answer 2

Highest in North Atlantic and Arctic Ocean, mid latitudes of S hem
high inventories are associated with water mass formation and subduction
- deep water formation in the N Atlantic, Intermediate and mode water in S Ocean

Question 3

ocean acidification

Answer 3

CO2 reacts with water to form H+ ions, increasing acidity
in normal conditions, almost all produced H+ combine with CO32- to form HCO3-
addition of anthropogenic CO2 into oceans lowers pH and consumes CO32-

pH scale is logarithmic

pH decrease in an almost uniform way
projected to decrease another 0.2 or 0.4

Question 4

Impact of acidification on marine organisms

Answer 4

consumption of CO32- and addition of CO2 facilitates dissolution of CaCO3
This affects structures like shells, corals, fish, urchins, pteropods, coccolithophores

Question 5

impacts of global warming on O2 concs

Answer 5

Ocean warming decreases oxygen solubility, therefore reducing oxygen

Reduced ocean mixing and slowdown of circulation decreases oxygen supply to the interior

Reduced biological production decreases oxygen consumption in the interior

Question 6

ocean deoxygenation

Answer 6

loss of oxygen from the oceans due to climate change

Most of the ocean has lost oxygen over the past decades, but patterns are complex and variable

will be stronger over mid to high lats, oxygenation may increase in low lats

Question 7

Impacts of deoxygenation on ecosystems

Answer 7

habitat reduction “habitat squeezing”
changes in range
while low O2 intolerant species lose habitat, other may gain habitat
dead zones

Question 8

geoengineering

Answer 8

aka climate engineering or climate intervention, deliberate and largescale
intervention in the Earth’s climate system with the aim of affecting adverse global warming

includes GHG removal and solar radiation mgmt

Question 9

greenhouse gas removal

Answer 9

Increase the removal of atmospheric CO2 and enhance the storage of
carbon in land, ocean and geological reservoirs

Question 10

solar radiation management

Answer 10

Manipulation of planetary solar absorption to counter climate
unintended side effects such as possible disruptions to marine ecosystems

Question 11

iron fertilization

Answer 11

example of geoengineering
fertilize HNLC regions with iron to produce phytoplankton blooms to fix CO2 –> CO2 depletion of surface, then more atm CO2 could be taken up by the surface, mitigate global warming and store CO2 in sediments when plankton die and sink