Collins, P

Hall-Spencer, J

Hart, M

Medina-Sanchez, A

Pettit, L

Prol-Ledesma, RM

Rodolfo-Metalpa, R

Smart, C

Wall-Palmer, D

English

Hall-Spencer, Jason

Plymouth Electronic Archive and Research Library

Geophysical Research AbstractsVol. 14, EGU2012-9754, 2012EGU General Assembly 2012© Author(s) 2012Investigation of the calcification response of foraminifera and pteropods tohigh CO2 environments in the Pleistocene, Paleogene and CretaceousM. Hart (1), L. Pettit (2), D. Wall-Palmer (3), C. Smart (4), J. Hall-Spencer (5), A. Medina-Sanchez (6), R.M.Prol Ledesma (7), R. Rodolfo-Metalpa (8), and P. Collins (9)(1) School of Geography, Earth & Environmental Sciences, Plymouth University, Plymouth PL4 8AA, United Kingdom(mhart@plymouth.ac.uk), (2) School of Marine Sciences & Engineering, Plymouth University, Plymouth PL4 8AA, UnitedKingdom (l.pettit@plymouth.ac.uk), (3) School of Geography, Earth & Environmental Sciences, Plymouth University,Plymouth PL4 8AA, United Kingdom (deborah.wall-palmer@plymouth.ac.uk), (4) School of Geography, Earth &Environmental Sciences, Plymouth University, Plymouth PL4 8AA, United Kingdom (csmart@plymouth.ac.uk), (5) School ofMarine Sciences & Engineering, Plymouth University, Plymouth PL4 8AA, United Kingdom(j.hall-spencer@plymouth.ac.uk), (6) Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, DelegacionCoyoacan, 04510 Mexico D.F., Mexico (alba_anms84@yahoo.com.mx, (7) Universidad Nacional Autonoma de Mexico,Ciudad Universitaria, Delegacion Coyoacan, 04510 Mexico D.F., Mexico (prol@geofisica.unam.mx), (8) School of MarineSciences & Engineering, Plymouth University, Plymouth PL4 8AA, United Kingdom (riccardo@rodolfo-metalpa.com), (9)Benthic Ecology Unit, Zoology, National University of Ireland, Galway, IrelandOcean acidification is regarded as a current problem and there is an extensive literature on how various organismsare responding to changes in oceanic pH: the result of increasing atmospheric pCO2. Acidification is, however, notjust a recent phenomenon and there are times in the geological record where pCO2 has been higher than presentday levels (especially in the Cretaceous and Paleogene). Understanding the response of various microfossil groupsto the changes in oceanic pH is on-going as part of a major investigation of ocean acidification in both modern and‘fossil’ environments.Extensive carbon dioxide vents have recently been described in the Wagner Basin (northern Gulf of Cali-fornia, Mexico), which cause dramatic changes in carbonate chemistry. The pHT decreased from 7.88 to 7.55 nearthe most active vents where the lowest saturation states of aragonite (ΩArag) and calcite (ΩCalc) were 0.95 and1.47 respectively. Foraminifera (unicellular protists) present in the top 2 cm of the sediment (both living and deadindividuals) had a range of mainly calcareous taxa (including Bolivina acuminata, B. acutula, Bulimina marginataand Nonionella basispinata). This is a normal composition for these water depths. The lack of dissolution featuresand the generally good preservation of the tests, even when viewed under a scanning electron microscope,were striking. With no evidence of breakage caused by transportation, it is assumed that this composition isrepresentative in terms of numbers of individuals and taxa represented. Benthic foraminifera from CO2 ventsaround the island of Ischia (Italy) have shown dramatic long-term effects of ocean acidification. The foraminiferaof the Wagner Basin appear to be surviving in high CO2 environments comparable to those that occurred duringthe Cretaceous–Paleogene “greenhouse” world where atmospheric pCO2 was much higher, but with calcareousforaminifera apparently thriving.In the Pleistocene, pCO2 levels are known to have fluctuated in parallel with δ18O during the glacial/interglacialcycles that characterise this interval. Calcification of pteropods through the last 250,000 years shows how thishas also fluctuated as a response to the changing oceanic pH. The changes seen in the pteropod assemblages ofthe Caribbean Sea are mirrored by changes known from the Gulf of Mexico, Mediterranean Sea, Red Sea, IndianOcean and the South China Sea – all records that confirm the variations in calcification as a global signal.

Investigation of the calcification response of foraminifera and pteropods to high CO2 environments in the Pleistocene, Paleogene and Cretaceous

Investigation of the calcification response of foraminifera and pteropods to high CO2 environments in the Pleistocene, Paleogene and Cretaceous

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