Vital effects in coccolith calcite; Cenozoic climate-pCO2 drove the diversity of carbon acquisition strategies in coccolithophores?

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doi: 10.1029/2012PA002339
Author(s): Bolton, Clara T.; Stoll, Heather M.; Mendez-Vicente, Ana
Author Affiliation(s): Primary:
University of Oviedo, Department of Geology, Oviedo, Spain
Volume Title: Paleoceanography
Source: Paleoceanography, 27(4). Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0883-8305 CODEN: POCGEP
Note: In English. 112 refs.; illus., incl. 2 tables
Summary: Coccoliths, calcite plates produced by the marine phytoplankton coccolithophores, have previously shown a large array of carbon and oxygen stable isotope fractionations (termed "vital effects"), correlated to cell size and hypothesized to reflect the varying importance of active carbon acquisition strategies. Culture studies show a reduced range of vital effects between large and small coccolithophores under high CO2, consistent with previous observations of a smaller range of interspecific vital effects in Paleocene coccoliths. We present new fossil data examining coccolithophore vital effects over three key Cenozoic intervals reflecting changing climate and atmospheric partial pressure of CO2 (pCO2). Oxygen and carbon stable isotopes of size-separated coccolith fractions dominated by different species from well preserved Paleocene-Eocene thermal maximum (PETM, ∼56 Ma) samples show reduced interspecific differences within the greenhouse boundary conditions of the PETM. Conversely, isotope data from the Plio-Pleistocene transition (PPT; 3.5-2 Ma) and the last glacial maximum (LGM; ∼22 ka) show persistent vital effects of ∼2ppm. PPT and LGM data show a clear positive trend between coccolith (cell) size and isotopic enrichment in coccolith carbonate, as seen in laboratory cultures. On geological timescales, the degree of expression of vital effects in coccoliths appears to be insensitive to pCO2 changes over the range ∼350 ppm (Pliocene) to ∼180 ppm (LGM). The modern array of coccolith vital effects arose after the PETM but before the late Pliocene and may reflect the operation of more diverse carbon acquisition strategies in coccolithophores in response to decreasing Cenozoic pCO2.
Year of Publication: 2012
Research Program: ODP Ocean Drilling Program
Key Words: 02 Geochemistry; 09 Paleontology, Paleobotany; Algae; Alkaline earth metals; Atlantic Coastal Plain; Bass River; Biodiversity; Biogenic processes; Biomineralization; Calcite; Calcium; Carbon dioxide; Carbonates; Cenozoic; Climate; Climate change; Coccolithophoraceae; Geochemistry; Isotope fractionation; Isotope ratios; Isotopes; Leg 174AX; Marine sediments; Metals; Microfossils; New Jersey; O-18/O-16; Ocean Drilling Program; Oxygen; Paleocene; Paleocene-Eocene Thermal Maximum; Paleoecology; Paleogene; Plantae; Productivity; Sediments; Size; Sr/Ca; Stable isotopes; Strontium; Tertiary; United States
Coordinates: N383000 N401500 W0740000 W0753500
Record ID: 2014045481
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