Mentor:’Dr.’Kathryn’Shamberger’’ · 1. Characterize’the’carbonate’chemistry’ 2....
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Ashley Davis Mentor: Dr. Kathryn Shamberger
Transcript of Mentor:’Dr.’Kathryn’Shamberger’’ · 1. Characterize’the’carbonate’chemistry’ 2....
Ashley Davis Mentor: Dr. Kathryn Shamberger
} Ocean acidifica<on is a process where CO2 dissolves in seawater causing the pH to decrease
} pH has dropped by 0.1 unit since the Industrial Revolu<on
PMEL, NOAA
} Corals use CO32-‐ to make CaCO3
2-‐ (aragonite and calcite)
} Deep-‐sea reefs are biodiversity hotspots that support commercial fisheries
} Reefs span a range of acidifica<on levels from 200-‐6500 m
Baco 2007, Oceanography
} Carbonate satura<on states ◦ Ω↓𝑎𝑟𝑔 = [𝐶𝑎↑2+ ][𝐶𝑂↓3↑2− ]/𝐾↓𝑠𝑝(𝑎𝑟𝑔)↑∗ Ω↓𝑐𝑎𝑙 = [𝐶𝑎↑2+ ][𝐶𝑂↓3↑2− ]/𝐾↓𝑠𝑝(𝑐𝑎𝑙)↑∗
} [Ca2+] determined from salinity
} [CO32-‐] calculated from Total Alkalinity (TA) and Dissolved
Inorganic Carbon (DIC)
} Ω (Undersaturated) < 1 < Ω (Oversaturated)
} Depth where Ω = 1 is the Satura&on Horizon
} Aragonite Satura<on Horizon
(ASH)
} Calcite Satura<on Horizon
(CSH)
Feely et al. 2004, Science
1. Characterize the carbonate chemistry
2. Iden<fy the ASH and CSH by evalua<ng the depths at which Ωarg and Ωcal = 1
3. Inves<gate spa<al varia<ons in the ASH and CSH based on la<tude
4. Compare 2014 and 2015 data to 1990s World Ocean Circula<on Experiment (WOCE) data
} 61 samples collected in 2014 from 3 loca<ons, and 90 samples collected in 2015 from 8 loca<ons
} Measure TA and DIC with VINDTA } CO2SYS Program used to calculate Ωcal and Ωarg
hgp://socco.org.za/facili<es/#Carbon
} Sample loca<ons in blue 2014 2015 2014/2015
P13
P14 P15 P16
} CSH = 600-‐800 m
} ASH = 500-‐600 m
North (35o N)
North (35o N)
South (23o N)
South (23o N)
} ASH depth is correlated with la<tude
} ASH Depth
} CSH Depth
Feely et al. 2004, Science
} Satura<on horizons deepen with northwest movement along the Hawaiian Island chain
} Deep-‐sea reefs that were previously in oversaturated waters are now located below the satura<on horizons
} Scien<sts can now observe how deep-‐sea reefs are reac<ng to increasing ocean acidifica<on
