Chemistry Reference
In-Depth Information
18
O of DIC produced by CO
2
reactions with H
2
O and OH
−
(at 25°C). Also shown
are equilibrium aragonite, corals, “bubbler” simulation at pH < 8.5 by McConnaughey (1989b), and the
equilibrium
Figure 17.
Calculated
δ
18
O of HCO
3
−
(B) and CO
3
2−
(C) at 25°C, based on analyses by McCrea (1950; triangles) and
Usdowski and Hoefs (1993; dots). These
δ
18
O values apply to the named chemical species, not to CO
2
derived from that species for mass spectrometric analysis. Inset: Relative rates of CO
2
reactions with H
2
O
and OH
−
in seawater at 25°C.
δ
18
O
compared to DIC in equilibrium with water. (DIC equilibrium as modeled by McCrea 1950 and Usdowski
and Hoefs 1993, as modified by Zeebe 1999). (B)
Figure 18.
Isotopic composition of forams from pH experiments by Spero et al. 1997. (A) Foram
δ
13
C for Spero's forams, compared with a non-
photosynthetic coral from Galapagos that presumably experienced only a limited pH range.
18
O vs.
δ
δ
