In 2004, CGRER awarded five seed grants totaling $100,000.
Historical Controls on the Evolution of Continental Plant and Insect Herbivore Biotas
John Nason considered the long-term effects of changing climate on genetic variability. His project examined the amount of genetic divergence in four Sonoran Desert plants and their dependent herbivorous insects. These organisms are thought to have migrated into their current Sonoran locations during the past 10,000 years, following the close of the Pleistocene. By using molecular genetics to compare the standing genetic variability of multiple plant-insect populations, this project determined whether genetic adaptability was lost during the northward migrations, or whether physical barriers induced more significant changes in the species’ genetics. The identification of migration-induced genetic changes could bode poorly for native communities that are likely to be forced to migrate by global warming; loss of genetic variability could reduce the environmental adaptability of native populations, making them more susceptible to possible extinction.
Capturing Iowa’s Industrial Age Record of Global Change
This project marked Iowa’s first attempt to use the isotopic composition of rainfall as a tool to fingerprint climatic trends of the past few hundred years. Jeff Dorale, Greg Ludvigson, and Dick Baker attempted to procure intact layered sediments from the depths of northwest Iowa’s Lake Okoboji. These annual sediment deposits, which are visibly layered and thus can be counted and aged, contain isotopes of oxygen that identify the geographic origin and airmass history of precipitation falling on the lake. They thus can be used to track the global air circulation patterns that cause precipitation in Iowa. Identifying the changes in isotopic composition allowed the investigators to identify evolving weather trends from before the Industrial Revolution to the present, an accomplishment that in turn may be predictive of Iowa’s future weather and precipitation patterns.
Stable Carbon Isotope Fractionation in Fatty Acid Biosynthesis of Piezophilic Bacteria and Implications to Paleoenvironmental Reconstruction
Jiasong Fang investigated whether biomarkers now used to decipher ancient oceanic environments are valid. The deep sea floor serves as the final repository for all oceanic activities. Sediments there contain bacterial byproducts (fatty acids) which are used to interpret the ocean’s paleoenvironments. However, interpretation of oceanic deposits is now based on our understanding of fatty acid synthesis and carbon isotope fractionation in surface-water bacteria. Fang used his grant to grow deep-water oceanic bacteria and compare their fatty acid synthesis and carbon isotope fractionation to that of surface-water bacteria. Differences or similarities found in this comparison were used to ensure that we are correctly reading the ocean’s ancient geochemistry and distant past.
How Accurately Can I Remotely Sense Surface Temperature? Practical Options for Investigators focuses on improving the accuracy of remote sensing equipment used to measure surface temperatures.
Brian Hornbuckle, Thomas Sauer, and Elwynn Taylor attacked inaccuracies inherent in the use of an infrared thermometer (IRT). Although the research instrument of choice when remotely obtaining detailed radiometric temperatures of land surfaces (vegetation, soils, etc.), an IRT actually compounds measurements of Earth surface emissions with those of infrared emissions from the sky. This grant concentrated on quantifying the resulting error and its variation, in preparation for submission of a major grant to determine standard, easily applied correction methods for this error.
Development and Implementation of an Aerosol Flow System for Laboratory Studies of the Impact of Atmospheric Aging on the Optical Properties of Mineral Dust Aerosol
Paul Kleiber and Vicki Grassian concentrated on the climatically significant interplay between light and dust. The absorption and scattering of solar radiation by mineral dust aerosol is crucial to the Earth’s temperature balance and climate. In simple terms, dust scattering of incoming solar radiation tends to cool the atmosphere, while dust absorption of outgoing terrestrial radiation has a warming effect. However, dust’s optical properties are so poorly understood that we don’t know whether mineral dust aerosol causes net global warming or cooling. This grant funded the construction and initial laboratory use of an aerosol flow-absorption cell designed to investigate this question.