508
Bijmaetal.
(not shown here) support the hypothesis that the
decrease in shell 8 13 C in the light should be explained in terms of a reduction in the scavenging
efficiency and that RUBISCO is of secondary
importance. The reason that the 8180 signal under
HL is not decoupled from [COn at high PC0 2
(Fig. 3 b) is because 8180 of metabolic CO 2 and
bulk CO 2 are probably not much different. Consequently, changes in the scavenging efficiency do not
effect shell 8180.
Conclusions
1) Shifts in pH (and for natural sea water in
[Cot]) have a significant impact on foraminiferal
shell 8 13 C and 8180.
2) Both symbiotic (Orbulina universa) and nonsymbiotic (Glabigerina bulla ides) species display
this effect. Therefore, we hypothesize that this
effect is common among other species.
3) The effect is species dependent and based on a
combination of kinetic and metabolic fractionation
processes.
4) A pH/carbonate isotope effect has important
implications for the interpretation of stable isotope
data in the fossil record. Shells calcifYing during cold
climate periods record isotopic signatures that cannot be interpreted directly using present-day relationships (cf. Lea et al. this volume)
5) Because the carbonate ion effect appears to be
a major factor influencing the foraminiferal isotope
record, calibration of the response in each ofthe
major paleoceanographic species is a necessary
next step towards fully understanding and utilizing
the oceanic isotopic record.
Acknowledgments
We thank the staff of the Wrigley Environmental
Science Center and E. Kincaid, C. Hamilton, J.
Dailey, E. Komsky, T. Mashiotta, M. Uhle, A.
Sanyal, D. Chan, E. Mochon, M. Cramer and V.
Hubner for their help in the field. Thanks go to S.
Schouten for the compound specific isotope analysis and to W. Berger and an anonymous reviewer
for many helpful suggestions. This research
was funded by the Deutsche Forschungsgemeinschaft (Sonderforschungsbereich 261
at Bremen University, contribution 203) and the
Program for the Advancement of Special Research
Projects at the Alfred Wegener Institute,
Germany (JB) and by the US National Science
Foundation (HJS and DWL). Data are available
under www.pangaea.de/Projects/SFB261.
References
Bard E, Arnold M, Duprat J, Moyes J, Duplessy JC
(1987) Reconstruction of the last deglaciation:
deconvolved records of 8 18 0 profiles, micropaleontological variations and accelerator mass
spectrometric C-14 dating. Clim Dyn 1987(1): 101-112
Be A WH (1979) Planktonic foraminifera: Ultrastructural
changes caused by calcification during gametogenesis in Globigerinoides sacculifer (Brady). Geol Soc
Am Abstracts with programs 11: 385-386
Be A WH (1980) Gametogenic calcification in a spinose
planktonic foraminifer, Globigerinoides sacculifer'
(Brady). Mar Micropaleontol5: 283-310
Be A WH (1982) Biology of planktonic foraminifera. In:
Broadhead TW (ed) Foraminifera: notes for a short
course. Department of Geological Sciences,
Knoxville, Tennessee, pp 51-92
Be A WH, Anderson OR (1976) Gametogenesis in planktonic foraminifera. Science 192(1-3): 890-892
Be A WH, Anderson OR, Faber WW Jr(1983) Sequence
of morphological and cytoplasmic changes
during gametogenesis in the planktonic foraminifer
Globigerinoides sacculifer (Brady). Micropaleontology 29(3): 310-325
Be A WH, Hemleben C, Anderson OR, Spindler M, (1979)
Chamber formation in planktonic foraminifera.
Micropaleontology 25(3): 294-306
Be A WH, Hemleben C, Anderson OR, Spindler M,
Hacunda J, Tuntivate-Choy S (1977) Laboratory and
field observations ofliving planktonic foraminifera.
Micropaleontology 23(2): 155-179
Be A WH, Hutson WH (1977) Ecology of planktonic
foraminifera and biogeographic patterns oflife and
fossil assemblages in the Indian Ocean. Micropaleontology 23(4): 369-414
Be A WH, Tolderlund DS (1971) Distribution and ecology ofliving planktonic foraminifera in surface waters of the Atlantic and Indian Oceans. In: Funnel
BM, Riedel WR (eds) The micropaleontology of
oceans. Cambridge Univ Press, pp 105-149
Bemis BE, Spero HJ, Bijma J, Lea DW (1998)
Reevaluation of the oxygen isotopic composition of
planktonic foraminifera: experimental results and
revised paleotemperature equations. Paleoceano-
Bijmaetal.
(not shown here) support the hypothesis that the
decrease in shell 8 13 C in the light should be explained in terms of a reduction in the scavenging
efficiency and that RUBISCO is of secondary
importance. The reason that the 8180 signal under
HL is not decoupled from [COn at high PC0 2
(Fig. 3 b) is because 8180 of metabolic CO 2 and
bulk CO 2 are probably not much different. Consequently, changes in the scavenging efficiency do not
effect shell 8180.
Conclusions
1) Shifts in pH (and for natural sea water in
[Cot]) have a significant impact on foraminiferal
shell 8 13 C and 8180.
2) Both symbiotic (Orbulina universa) and nonsymbiotic (Glabigerina bulla ides) species display
this effect. Therefore, we hypothesize that this
effect is common among other species.
3) The effect is species dependent and based on a
combination of kinetic and metabolic fractionation
processes.
4) A pH/carbonate isotope effect has important
implications for the interpretation of stable isotope
data in the fossil record. Shells calcifYing during cold
climate periods record isotopic signatures that cannot be interpreted directly using present-day relationships (cf. Lea et al. this volume)
5) Because the carbonate ion effect appears to be
a major factor influencing the foraminiferal isotope
record, calibration of the response in each ofthe
major paleoceanographic species is a necessary
next step towards fully understanding and utilizing
the oceanic isotopic record.
Acknowledgments
We thank the staff of the Wrigley Environmental
Science Center and E. Kincaid, C. Hamilton, J.
Dailey, E. Komsky, T. Mashiotta, M. Uhle, A.
Sanyal, D. Chan, E. Mochon, M. Cramer and V.
Hubner for their help in the field. Thanks go to S.
Schouten for the compound specific isotope analysis and to W. Berger and an anonymous reviewer
for many helpful suggestions. This research
was funded by the Deutsche Forschungsgemeinschaft (Sonderforschungsbereich 261
at Bremen University, contribution 203) and the
Program for the Advancement of Special Research
Projects at the Alfred Wegener Institute,
Germany (JB) and by the US National Science
Foundation (HJS and DWL). Data are available
under www.pangaea.de/Projects/SFB261.
References
Bard E, Arnold M, Duprat J, Moyes J, Duplessy JC
(1987) Reconstruction of the last deglaciation:
deconvolved records of 8 18 0 profiles, micropaleontological variations and accelerator mass
spectrometric C-14 dating. Clim Dyn 1987(1): 101-112
Be A WH (1979) Planktonic foraminifera: Ultrastructural
changes caused by calcification during gametogenesis in Globigerinoides sacculifer (Brady). Geol Soc
Am Abstracts with programs 11: 385-386
Be A WH (1980) Gametogenic calcification in a spinose
planktonic foraminifer, Globigerinoides sacculifer'
(Brady). Mar Micropaleontol5: 283-310
Be A WH (1982) Biology of planktonic foraminifera. In:
Broadhead TW (ed) Foraminifera: notes for a short
course. Department of Geological Sciences,
Knoxville, Tennessee, pp 51-92
Be A WH, Anderson OR (1976) Gametogenesis in planktonic foraminifera. Science 192(1-3): 890-892
Be A WH, Anderson OR, Faber WW Jr(1983) Sequence
of morphological and cytoplasmic changes
during gametogenesis in the planktonic foraminifer
Globigerinoides sacculifer (Brady). Micropaleontology 29(3): 310-325
Be A WH, Hemleben C, Anderson OR, Spindler M, (1979)
Chamber formation in planktonic foraminifera.
Micropaleontology 25(3): 294-306
Be A WH, Hemleben C, Anderson OR, Spindler M,
Hacunda J, Tuntivate-Choy S (1977) Laboratory and
field observations ofliving planktonic foraminifera.
Micropaleontology 23(2): 155-179
Be A WH, Hutson WH (1977) Ecology of planktonic
foraminifera and biogeographic patterns oflife and
fossil assemblages in the Indian Ocean. Micropaleontology 23(4): 369-414
Be A WH, Tolderlund DS (1971) Distribution and ecology ofliving planktonic foraminifera in surface waters of the Atlantic and Indian Oceans. In: Funnel
BM, Riedel WR (eds) The micropaleontology of
oceans. Cambridge Univ Press, pp 105-149
Bemis BE, Spero HJ, Bijma J, Lea DW (1998)
Reevaluation of the oxygen isotopic composition of
planktonic foraminifera: experimental results and
revised paleotemperature equations. Paleoceano-