Chemical and biogeochemical effects Flashcards
How does the ability of the oceans to absorb CO2 change as atmospheric CO2 changes?
The ability of sea water to absorb CO2 drops as atmospheric CO2 increases
How do phytoplankton respond to iron availability?
If there is more dust present, there is more iron available … this encourages phytoplankton growth
What chemical processes do we need to consider in our models?
- Ocean chemistry
- Role of ozone
- Atmospheric chemistry
- Methane lifetime
- Volatile Organic Compounds (VOCs)
What is the average pH of the oceans?
pH 8
How does the ocean act as a biological pump?
- Phytoplankton absorb CO2
- Zooplankton consume phytoplankton
- Respiration returns CO2 to the atmosphere
- Some organic matter sinks to the deep ocean … net uptake of CO2
Where is CO2 recycled in the ocean?
In the upper 1 km
What % of organic matter sinks to the deep ocean?
5-10%
What is phytoplankton growth limited by?
- Light
- Nutrients (nitrogen, phosphorous, iron)
In what regions is iron a major limiting nutrient?
- Equitorial pacific
- Southern Ocean
How is iron delivered to the ocean?
Through dust
Where in the ocean do your find nutrient ‘deserts’?
The centre of gyres
Who proposed the iron hypothesis?
John Martin
What is the iron hypothesis?
- Fertilise low-chlorophlull zones
- Create algal blooms
- Boost primary productivity
- Drive down CO2
How many studies on iron fertilisation experience have shown a CO2 draw down?
Only one of over 12 studies … (Boyd, 2000: showed a doubling of biomass and a CO2 draw down)
When were commercial iron fertilisation experiments banned?
2013
