Paleorecords of Biotic and Abiotic Particles in Polar Ice Cores
The U.S. ice core research community has proposed a deep ice-coring program in West Antarctica (WAIS Divide) that will develop a unique series of interrelated climate, ice dynamics, and biologic records focused on understanding interactions among global earth systems. A significant component of the WAIS Divide program will be the development of a climate record with an annual layer chronology for the most recent 40,000 years. The record will also extend, at lower temporal resolution, to approximately 100,000 years before present. These records will enable comparison of paleo-environmental conditions between the northern and southern hemispheres, in conjunction with the study of greenhouse gas concentrations in the paleo-atmosphere, with greater resolution than previously possible. We propose to develop a flow cytometer-based analytical system for the continuous detection and characterization of abiotic and biotic particles in ice cores and mate it with a unit already developed for the continuous flow analysis of trace elements. We hypothesize that (i) the density of microorganisms within ice cores will co-vary with total particle density and trace element concentration, (ii) the physiological state of microorganisms within meteoric ice deteriorates with depth and (iii), the subglacial environment is a region of active microbial growth and a source of new organic carbon in the polar environment. These specific hypotheses are cast under the overarching theme "Antarctic glacial ice contains a significant reservoir of organic carbon that reflects past climatic events." The proposed research will utilize archived ice cores to both develop methodology and produce new data that will directly address our hypotheses. These hypotheses will be expanded upon and further tested in a future proposal to characterize biotic and abiotic particles in ice to be retrieved from the WAIS Divide bedrock core.
Broader Impacts. The WAIS Divide ice-coring project will be the first to explicitly integrate biology, glaciochemistry and climate, and thus will be the bellwether for future interdisciplinary studies on ice cores. As such, our proposal will have broader impacts beyond the specific scientific questions that will be addressed. Specifically, this proposal will train a young female scientist (Dr. Christine Foreman) and undergraduate students in the interdisciplinary aspects of ice core research, will introduce a Native American student to the sciences, and will broaden the field of scientists involved in ice core research to include biologists.