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Department of Earth and Environmental Sciences

Mathiue Richaud

Mathieu Richaud

Ph.D., Northern Illinois University, DeKalb, 2006

Associate Professor
Department of Earth & Environmental Sciences 
California State University, Fresno
2576 E. San Ramon Ave., Mail Stop ST-24 
Fresno, CA 93740 

Tel.  (559) 278-4557 
Fax. (559) 278-5980 

Science II 326

Office Hours:
Tu    12-1pm & 2-3pm (Online)
Th    12-3pm  (Online)

Teaching Interests

My teaching interests are varied, but I tend to teach mostly classes in Oceanography (EES 167) and the geology of California (EES 168).
Furthermore, I am interested in global biogeochemical cycles, and habitat mapping of the seafloor.

Research Interests

My research interests comprise the broad fields of paleoceanography and global change with an emphasis on the geochemical cycles of marine carbon and their variations in the past within the equatorial Pacific and Atlantic. My approach is interdisciplinary in nature, involving studies in stable and radio–isotopes, organic geochemistry and micropaleontology.

• Current Research Interest in the Eastern Equatorial Pacific

Numerous studies have highlighted the importance of pCO2 as an amplifier and/or primary driver of the glacial/interglacial cycles, though the scientific community remains ignorant of the exact mechanisms causing these cycles. A leading hypothesis for the cause of glacial/interglacial atmospheric CO2 change involves the extraction of carbon from the surface ocean by biological production, either at low or high latitudes, coupled with changes in the marine calcium carbonate and silica budgets (Archer et al., 2000; Sigman and Boyle, 2000; Brzezinski et al., 2002). The central theme of my research is the glacial/interglacial variations of biogenic fluxes (CaCO3 , OrgC and Si) across the equatorial Pacific (Richaud et al., 2007).

Additionally, I study how equatorial Pacific biological and chemical marine systems differ from their counterparts in the equatorial Atlantic (Loubere et al., 2011). Both studies contribute to a better understanding of the various connections and relationships between low and high latitude oceans in terms of biology, chemistry and circulation dynamics.

• Current Research Interest in the North Atlantic Ocean (Svalbard)

I am interested in the structure of benthic environments and the paleochemical record of foraminifera, small marine organisms pervasive throughout the oceans. I am part of a group of researchers that maintained a seabed sampling program from 2007 to 2010 on the western European margin of the Fram Straits extending into the fjords of Svalbard in the northern North Atlantic. We are interested in assessing how benthic foraminiferal shell geochemistry is sensitive to the geochemical conditions of the microhabitats selected by particular foraminiferal species. Understanding these microhabitats is essential for the proper interpretation of the proxies, mainly of which have been extensively used to develop paleoceanographic tracers (Loubere et al., 2011).

• Current Research Interest in the Canterbury Basin, New Zealand

In 2010, I was a shipboard participant onboard the R/V JOIDES Resolution during IODP Expedition 317. Several graduate students work with me to reconstruct high-resolution paleodepth estimates via benthic foraminifera assemblages and a sequence-stratigraphy model of foraminiferal assemblages, combined with detailed facies and lithology analyses, over a complete Late Quaternary transgressive-regressive sequence. Sites U1353 and U1354 provide a stratigraphic record of depositional cycles through the Holocene and late Quaternary across the shallow-water environment most directly affected by relative sea level change. Both cores are suitable for high-resolution study of recent glacial cycles in a continental shelf setting, allowing to estimate the timing and amplitude of global sea level change and to document the sedimentary processes that operate during sequence formation (Exp. 317 Scientists, 2010). If the vertical movements of a basin floor can be reconstructed from the sedimentary record, these movements can be more accurately constrained when information from the sedimentary history is combined with paleodepth estimates derived from fauna (Hayward,
1986; Murray, 1991; van Hinshergen et al., 2005).

• Involvement in other research projects

Several undergraduate and graduate students work with me on coastal marine geology, focusing our efforts on the Morro Bay sand spit along the Central Coast of California. The central coast of California is hit every three to seven years by intense El Niño-Southern Oscillation (ENSO) events that damage the coastline in several different ways (Storlazzi et al, 1999). Elevated sea levels, increased wave height, and higher precipitation characterize ENSO events and are largely to blame in erosion of the coastline (Allan and Komar, 2006). We postulate that ENSO events accelerates beach sand erosion. The project uses a vessel-based LiDAR system at CSUMB Seafloor Mapping Lab that will provide high-resolution imagery to more accurately analyze, calculate and model erosion rates along the Morro Bay sandspit.

Selected Publications

Mekik, F., Anderson, R., Loubere, P., Francois, R., Richaud,
M. (2012) The Mystery of the Missing Deglacial Carbonate
Preservation Maximum, Quaternary Science Reviews, 39, 60–72,
doi:10.1016/j.quascirev.2012.0 1.024

Loubere, P., Fariduddin, M., and Richaud, M. (2011) Glacial ma-
rine Nutrient and Carbon Redistribution: Evidence from the Trop-
ical Ocean, Geochemistry, Geophysics, Geosystems, 12, Q08013,

Loubere, P., Jacobson, B., Klitgaard Kristensen, D., Husum, K., Jernas,
P. and Richaud, M. (2011) The structure of Benthic Environments and
the Paleochemical Record of Foraminifera, Deep-Sea Research Part 1, 58,
535–545, doi:10.1016/j.dsr.2011.02.011

Richaud, M., (2010) Anthropogenic climate change, in Warf, B. (ed.),
The Encyclopedia of Geography (Warf B, Jankowski P, Leib J, Solomon
BD, and Welford MR, eds.). Volumes 1-5. Thousand Oaks, CA: Sage

Richaud, M., (2010) The Poles, The Encyclopedia of Geography (Warf
B, Jankowski P, Leib J, Solomon BD, and Welford MR, eds.). Volumes
1-5. Thousand Oaks, CA: Sage

Expedition 317 Scientists, (2010) Canterbury Basin sea level: Global and
local controls on continental margin stratigraphy, IODP Preliminary Re-
port, 317., doi:10.2204/

Richaud, M., Loubere, P., Pichat, S., Francois, R. (2007) Changes in
opal flux and the rain ratio during the last 50,000 years in the equatorial Pacific, Deep–Sea Research Part II: Topical Studies in Oceanography, 54, 5–7, 762–771, doi:10.1016/j.dsr2.2007.01.012

Loubere, P., Richaud, M. (2007) Some reconciliation of Glacial–
Interglacial calcite flux reconstructions for the eastern equatorial Pacific, Geochemistry Geophysics Geosystems, 8, Q03008, doi:10.1029/2006GC001367

Loubere, P., Richaud, M., Mireles, S., (2007) Variability in tropi-
cal thermocline nutrient chemistry on the glacial/interglacial timescale, Deep–Sea Research Part II: Topical Studies in Oceanography, 54, 5–7, 747–761, doi:10.1016/j.dsr2.2007.01.005

Loubere, P., Richaud, M., (2007) Some reconciliation of Glacial–
Interglacial calcite flux reconstructions for the eastern equato-
rial Pacific, Geochemistry Geophysics Geosystems, 8, Q03008,

Mekik, F., Loubere, P., Richaud, M., (2007) Rain ratio variation in the
Tropical Ocean: Tests with surface sediments in the eastern equatorial
Pacific, Deep–Sea Research Part II: Topical Studies in Oceanography,
54, 5–7, 706–721, doi:10.1016/j.dsr2.2007.01.010

Loubere, P., Richaud, M., Liu, Z., Mekik, F., (2003) Oceanic conditions in the eastern equatorial Pacific during the onset of ENSO in
the Holocene, Quaternary Research, 60, 142–148, doi:10.1016/S0033-