Teaching Interests:
My teaching interests are varied. In the Fall of ’07, I will be teaching an introductory class on the climate of the Cenozoic: how and in which extent did the climate change, were these changes gradual or stepwise, what caused the warmings and coolings and how can they be investigated. I will also teach a class on Sedimentology.
Furthermore, I am interested in Global Biogeochemical Cycles, Historical Geology, Micropaleontology and Ocean Remote Sensing.
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 Interests
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 as a test of the “silicic acid leakage” hypothesis.
My data indicates that the “silic acid leakage” hypothesis cannot explain the minimum in atmospheric CO2 concentration recorded during the LGM as the peak in silica accumulation rate is seen between 40 and 60 kyr B.P. (Richaud et al., 2007).
Additionally, I study how equatorial Pacific biological and chemical marine systems differ from their counterparts in the equatorial Atlantic. 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.
• Involvement in other research projects
During the course of my Ph.D., I was involved in a variety of smaller projects. I recently participated in a study of carbonate preservation in marine cores using planktonic foraminifera for evidence of an oceanic driving mechanism behind the pre–anthropogenic pCO2 rise (Mekik et al., in review). Additionally, I am still involved in the gathering and mapping of opal content of marine equatorial Pacific top–cores (Mekik et al., 2007). I helped collect isotopic data, from the scientific literature and in the laboratory, of planktonic foraminifera shells as tracers of oceanic changes in thermocline and surface ocean nutrient concentrations in the eastern equatorial Pacific and Atlantic (Loubere et al., 2007).
I also participated in a research effort to reconcile carbonate accumulation rates in the EEP where results based on two different methods to constrain accumulation rates showed opposite results (Loubere and Richaud, 2007). Finally, I participated to the reconstruction of the oceanic conditions in the eastern equatorial Pacific during the onset of ENSO in the Holocene (Loubere et al., 2003).
• Future Research Interests
I plan to continue working in this field but I desire to shift my attention to new geographic
areas. I would like to expand the methods and tools learned during my Ph.D. to the region of the Makassar Strait (Indonesia) and western Australia. As a whole, this area is stongly influenced by the Indonesian Throughflow (ITF). Through the Indonesian Seas, the ITF is the main return surface flow of the conveyor belt from the Pacific to the Indian Ocean, and later to the Atlantic Ocean. Knowledge of past variation in biogenic fluxes, primary productivity and nutrient utilization contributes to the understanding of past changes
of the regional chemical and physical systems. To my knowledge, very few recent studies have looked at reconstructing this aspect of the ITF.
Additionally, it is of great interest to evaluate how the changes in the chemistry and physics seen in the equatorial Pacific, over a glacial/interglacial cycle, are transferred to the Indian Ocean. This ought to be done as many studies have clearly shown the physical links between Indian Ocean productivity and the North Atlantic region. Thus, connecting the Pacific to the
Indian Ocean leads to a global view of biogeochemical response of the ocean to climate change.
In the long term, it would be necessary to know how tropical and equatorial upwelling zones changed in the past to fully assess the pertinence and the significance of the marine biological pump as a mechanism to explain the atmospheric glacial/interglacial pCO2 changes.