Gerilyn Soreghan, University of Oklahoma, EAR-1338331 Sarah Aciego, University of Michigan, EAR-1337440 Linda Hinnov, Johns Hopkins University, EAR-1337454 Nicholas Heavens, Hampton University, EAR-1337463
Overview Geologic data indicate that the tropical atmosphere during the Permo-Pennsylvanian (300 Million years ago) was dust-rich. In addition, algae predominated in late Paleozoic marine ecosystems. These observations, combined with predictions from climate modeling, prompt two over-arching hypotheses driving the proposed research: 1) the unusual tropical dustiness reflects dust production by tropical upland glaciers, and 2) atmospheric dustiness fertilized marine ecosystems. Dust forces the climate system by affecting radiative forcing and atmospheric moisture, and by influencing the biosphere, but these effects are poorly known. In this research, PIs will collect data to constrain spatial (low-mid latitude) and temporal (glacial-interglacial and longer) variations in atmospheric 'dustiness,' sources of the dust, and influences between dust and ecosystem composition in order to address their over-arching hypotheses, and clarify the relationships among atmospheric dustiness, climate, and the biosphere.
Intellectual Merit This research will reveal process links among dust, climate, and the biosphere within an icehouse, at glacial-interglacial scales. Owing to the known importance but great uncertainty of both the direct and indirect effects of dust on climate, results will expand understanding of Earth-system behavior. Tropical glaciation at low elevations implies much more widespread glaciation than currently accepted, and --if verified-- would force the community to test this hypothesis with new modeling approaches. The models to be used are identical to those used for present and future climate, and thus improvements made through the proposed work will inform modeling of Earth's climate in general. If the hypothesis that atmospheric dustiness forced marine biotic systems toward nutrient-rich conditions is confirmed, it implies a remarkably dusty Earth, and clarifies Earth-system behavior to dust-sourced fertilization. These results are relevant to growing discussions regarding geo-engineering schemes to control future climate change.
Broader Impacts Cross-disciplinary training will occur via exchanges between geological and geochemical labs, geologists and modelers, and in joint field excursions and progress meetings. PhD students will mentor middle-school teachers through a formal summer program. Undergraduates will conduct senior theses and present at Undergraduate Research Day and national meetings. Both will interact with middle- and high-school students through a formal course on STEM education. The lead investigators will use components of the research to teach at university levels, as well as in museum, and community outreach. Ties will be established and strengthened among all participant institutions, which includes an Historically Black University, as well as international partners. This research will help ignite the research careers of three young investigators (2 with no prior NSF support). Data will be archived and shared via publications, and web-accessible tools.
