Dust levels in the atmosphere have important potential effects on climate, including impacts on the Earth's radiative balance and on marine primary productivity, and thus atmospheric CO2, via "fertilization" of surface waters. Information about changes in dust provenance and flux is critical to ground truth atmospheric circulation models, which are are used to investigate the role that dust has on feedbacks which connect continental conditions and global climate.
This research, conducted by scientists at Texas A & M University, investigates dust provenance changes in the eastern equatorial Pacific during the late Quaternary. The researchers will perform a temporal study along a transect of sediment cores crossing the equator, as well as a spatial study of modern sediments from a wide area of the eastern equatorial Pacific, analyzing the radiogenic isotope and trace element geochemistry of the dust fraction. In addition, they will determine radiogenic isotope signatures of various end members samples representing the potential dust sources to the Eastern Equatorial Pacific (China, NW South America, SW North America, Australia, northern Africa). This paleo-provenance study will lead to better understanding of the large-scale meridional atmospheric circulation variability of the tropics, which in turn can shed light of past climate forcing mechanisms.
Funding supports a PhD student and provides opportunities for undergraduate involvement in research. Results will be incorporated into courses taught by the lead investigator.
Funding from this grant has enabled me and my group to develop and use radiogenic isotopes as proxies for tracing current and past wind circulation patterns in the eastern equatorial Pacific and deep-ocean circulation patterns in the North Atlantic. Our work has enabled us to ascertain changes in both wind and ocean circulation patterns over the past 25,000 years, a time in Earth's history over which climate changed dramatically from cold to warm. Knowing the changes in ocean-atmosphere circulation over this time period provides critical data for modelers who are attempting to understand what the future has in store with respect to climate variability. An outstanding problem is that we have no direct data for processes that occur on time scales longer than the record of scientific observations (for the oceans, 50-100 years). We need to understand these processes to understand the impacts of large-scale anthropogenic release of greenhouse gases, since the expected impact is large and will take hundreds of years to pass. I have incorporated the scientific results derived from this research into the various levels of geosciences courses I teach. For example, the research from this project has been used in one of my advanced graduate radiogenic isotope geochemistry classes, which focuses on geochemical proxies in paleoceanography. In addition the cutting-edge research produced in this project has enabled me to attract and recruit a more diverse and talented array of M.S. and Ph.D. students. With resepect to undergraduate research, three undergraduate students have benefited from working with me in the lab on this project. All three of the undergraduates, went on to pursue graduate studies, most likely because of their hands-on, direct research experience provided with funding from this project.
