INSTAAR: Tom Marchitto

Research Scientist of INSTAAR; Assistant Professor of Geological Sciences, Univ. of Colorado at Boulder.

PhD, MIT/WHOI Joint Program, 1999.

Tom.Marchitto@colorado.edu
(303) 492-7739

INSTAAR Directorate Members

Specialty: Quaternary paleoclimate, paleoceanography, and past ocean chemistry.

Research Interests: An understanding of the modes and mechanisms of past climate variability is a vital prerequisite for understanding our current and future climate. I am mainly interested in paleoceanography, specifically large-scale changes in ocean circulation and chemistry that occur over millennial (and shorter) timescales. Most of my work has focused on the last full glacial-interglacial cycle, spanning roughly the past 130,000 years. Major variations in ocean circulation, from abyssal depths to the surface, are believed to have strongly influenced climate via the transport of heat. The oceans also exert control over atmospheric levels of carbon dioxide, an important "greenhouse" gas. Such changes are reflected in the physical and chemical properties of seawater, including temperature, salinity, the isotopic composition of dissolved inorganic carbon, and the concentrations of various nutrients. We use the calcitic shells of protozoa called foraminifera as recorders of these properties. By analyzing and dating sediment cores that contain foraminifera, we can reconstruct ocean chemistry and inferred circulation patterns during the past.

Selected Publications:

Marchitto, T. M., S. P. Bryan, W. B. Curry, and D. C. McCorkle, 2007. Mg/Ca temperature calibration for the benthic foraminifer Cibicidoides pachyderma, Paleoceanography, 22(1), PA1203, doi:10.1029/2006PA001287.
Marchitto, T. M., and W. S. Broecker, 2006. Deep water mass geometry in the glacial Atlantic Ocean: A review of constraints from the paleonutrient proxy Cd/Ca, Geochemistry, Geophysics, Geosystems, 7(12), Q12003, doi:10.1029/2006GC001323.
Marchitto, T. M., 2006. Precise multi-elemental ratios in small foraminiferal samples determined by sector field ICP-MS, Geochemistry, Geophysics, Geosystems, 7(5), Q05P13, doi:10.1029/2005GC0010186.
Marchitto, T. M., J. Lynch-Stieglitz, and S. R. Hemming, 2005. Deep Pacific CaCO3 compensation and glacial-interglacial atmospheric CO2, Earth and Planetary Science Letters, 231.
Ortiz, J. D., S. B. O'Connell, J. DelViscio, W. Dean, J. D. Carriquiry, T. M. Marchitto, Y. Zheng, and A. van Geen, 2004. Enhanced marine productivity off western North America during warm climate intervals of the past 52 k.y., Geology, 32, 521-524.
Marchitto, T. M., and P. B. deMenocal, 2003. Late Holocene variability of upper North Atlantic Deep Water temperature and salinity, Geochemistry, Geophysics, Geosystems, 4(12), 1100.
Marchitto, T. M., D. W. Oppo, and W. B. Curry, 2002. Paired benthic foraminiferal Cd/Ca and Zn/Ca evidence for a greatly increased presence of Southern Ocean Water in the glacial North Atlantic, Paleoceanography, 17(3), 1038, DOI 10.1029/2000PA000598.
Koutavas, A., J. Lynch-Stieglitz, T. M. Marchitto, and J. P. Sachs, 2002. El Niño-like pattern in Ice Age tropical Pacific sea surface temperature, Science, 297, 226-230.
Marchitto, T. M., W. B. Curry, and D. W. Oppo, 2000. Zinc concentrations in benthic foraminifera reflect seawater chemistry, Paleoceanography, 15, 299-306.
Marchitto, T. M., G. A. Jones, G. A. Goodfriend, and C. R. Weidman, 2000. Precise temporal correlation of Holocene mollusk shells using sclerochronology, Quaternary Research, 53, 236-246.
Marchitto, T. M., W. B. Curry, and D. W. Oppo, 1998. Millennial-scale changes in North Atlantic circulation since the last glaciation, Nature, 393, 557-561.

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