Collins, P

Hall-Spencer, JM

Hart, MB

Medina-Sánchez, A

Pettit, L

Prol Ledesma, RM

Rodolfo-Metalpa, R

Smart, CW

English

Plymouth Electronic Archive and Research Library

AvH7-467th Alexander von Humboldt International ConferencePenang, Malaysia, June 20-24, 2011© Author(s) 2011Foraminifera resist ocean acidification in the Wagner Basin underconditions similar to high CO2 environments of the Cretaceous-PaleogeneL. Pettit (1), M.B. Hart (1), A. Medina-Sánchez (2), C.W. Smart (1), P. Collins (3), R. Rodolfo-Metalpa (1), J.M.Hall-Spencer (1), and R.M. Prol Ledesma (2)(1) University of Plymouth, Drake Circus, Plymouth PL4 8AA, United Kingdom (riccardo@rodolfo-metalpa.com), (2)Universidad Nacional Autónoma de México, Ciudad Universitaria, Delegación Coyoacán, 04510 México D.F., Mexico, (3)Benthic Ecology Unit Zoology, National University of Ireland, Galway, IrelandIn 2007 and 2010 gas vents along the Wagner Fault (northern Gulf of California, Mexico; Canet et al., 2010) wereinvestigated, recording their effects on the carbonate chemistry of the sea water and the surrounding benthos. Over300 massive, but diffuse seafloor gas vents were discovered causing dramatic changes in the carbonate chemistry.The pHT decreased from 7.98 out of the fault to 7.55 near the most active vents where the lowest saturation statesof aragonite (Ωa) and calcite (Ωc) were 0.95 and 1.47 respectively. Large areas of the fault region had pH 7.7-7.8suggesting continuous diffuse gas emissions.Foraminifera (unicellular protists) present in the top 2 cm of the sediment (both living and dead individuals) hada range of mainly calcareous taxa (including Bolivina acuminata, B. acutula, Bulimina marginata, Nonionellabasispinata and Psedoparella brayana). This is a normal composition for these water depths and it was striking inthe lack of dissolution features, damaged tests and the generally good preservation of the tests even when viewedat high magnification in a scanning electron microscope. With no evidence of breakage caused by transportation,as it is assumed that this composition is representative in terms of numbers of individuals and taxa represented. Insediments of similar pH around the island of Ischia (Italy), the assemblage of foraminifera in waters of comparablepH is much reduced, but carbonate saturation is different (Dias et al., 2010). The foraminifera of the Wagner Basinappear to be surviving in high CO2 environments that are comparable to those that occurred during the Cretaceous–Paleogene “greenhouse” world where atmospheric pCO2 was very much higher but with calcareous foraminiferaapparently thriving (Tyrrell & Zeebe 2004; Zachos et al., 2005)

Foraminifera resist ocean acidification in the Wagner Basin under conditions similar to high CO2 environments of the Cretaceous-Paleogene

Foraminifera resist ocean acidification in the Wagner Basin under conditions similar to high CO2 environments of the Cretaceous-Paleogene

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