carbon and biogeochemistry of the sea ice zone bates et al., (2006) stephens and keeling (2002)...
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Carbon and biogeochemistry of the sea ice zone
Bates et al., (2006)
Stephens and Keeling (2002)Sigman et al., (2010)
Takahashi et al., (2009)
Arrigo et al., (2010)
McNeil et al., (2007)
Ventilation and subduction in the sea ice zone(Arctic)
Steele et al., (1995)
AW = Atlantic water
ASW = Arctic surface water
CDW = Cold deep water
CHW = Cold halocline water
DIC Pump Hypothesis
Mirabilite crystals Na2SO4·10H2O
(Arctic sea ice)
Ikaite crystalsCaCO3·6H2O
(Weddell Sea ice)
(Light et. al, 2003)
(Dieckmann et. al, 2008)
DIC
pump
Alk.
flux ?
DIC Pump Hypothesis
DIC
pump
Alk.
flux ?
Zero sum gain scenario
Arrigo et. al., 2008
Primary production and carbon uptake in the SIZ
© National Geographic
CO2 rectification hypothesis
(Yager et al., 1995)
Export
production?
Alk.
flux ?
CO2
flux ?
Springtime fluxes (S.O.)
Export
production?
Alk.
flux ?
CO2
flux ?
Loose et al., (2011)
• Net CO2
flux into mixed layer = Primary production – Gas exchange + upwelling*
• Gas exchange (k) is usually inferred, rarely measured.
• We need to measure Primary production + gas exchange at the same time in the SIZ.
Do we have estimates of k in sea ice cover and do we believe them?
Fanning and Torres (1991)
Loose and Schlosser (2011)
Air-sea gas exchange depends on aqueous turbulence
• Shear in the ice-ocean boundary layer (IOBL) (McPhee, 1992; McPhee, 2008, Andreas, 1986).
• Buoyant convection/stratification (Lombardo and Gregg, 1989; Morison et al., 1992)
• Short-period wind waves (Frew et al., 2004) and their interactions with ice floes
How to measure gas exchange on MOSAiC?
Smethie et al., (1985), Peng et al., (1979)
226Ra originates in the sediments and bedrock.
226Ra decays to 222Rn.222Rn has 3.8 day half-life.
5. How to measure gas exchange and primary production together?
National Geographic
Δ(O2
/Ar) Method:
Ar behaves like “abiotic O2
”
Solubility of Ar ~ Solubility of O2
Diffusivity of Ar ~ Diffusivity of O2
Δ(O2
/Ar) reflects excess oxygen of biogenic origin.
Net Community O2 production (NCP) = kρΔ(O2/Ar)