Why study the marine silicon cycle

1
Why study the marine silicon cycle?

• Major nutrient needed by Si mineralizers
• Diatoms
• Role in biogeochemical cycles
• Link to carbon cycle

2
Silicate

• Structural material
• Diatoms
• Radiolarians
• Silicoflagellates
• Sponges

3
Silica in Water

• Silicon dioxide
• SiO2 2H2O H4SiO4
• H4SiO4 (monosilicic acid)
• Three forms
• Reactive
• Colloidal
• Suspended particles

4

• Inputs
• Riverine 80
• Aeolian deposition 7
• Dissolution of seafloor basalts 7
• Hydrothermal vents 6

5
Bloom n Bust Lifestyle

• Bloom
• Spring
• High nutrients and light
• Bust
• Depletion of nutrients, esp. silicon
• Sink
• Resting spores

6
Whats so good about this?

• Sinking diatoms export from the atmosphere into
  the ocean interior
• Diatoms play a key role in the biogeochemical
  cycle of silicon in the ocean
• Biogenic silica in diatom skeletons acts as an
  effective pH buffer, facilitating the conversion
  of bicarbonate to dissolved CO2