PALEOFIRE · Developing a 4000-year East African fire history from the Kilimanjaro ice core

Developing a 4000-year East African fire history from the Kilimanjaro ice core

Project context and objectives The work to date has consisted of five phases: 1) determining levoglucosan in the Kilimanjaro Northern Ice Field 2 (NIF2) ice core; 2) analysing trace elements in NIF2; 3) expanding East African fire history records through examining levoglucosan and charcoal in Lakes Challa and Victoria; 4) combining ice-core data with general circulation models (GCMs) and; 5) increasing the scope of the work by investigating levoglucosan in the NEEM (Greenland) and EPICA Dome C (Antarctica) ice cores Project work 1) Determining levoglucosan in Kilimanjaro NIF2 The Kilimanjaro ice cores (3º04.6'S; 37º21.2'E, 5893 metres above sea level) supply a high-resolution equatorial proxy record that provides a nearly continuous record of climate parameters (temperature, accumulation, atmospheric chemistry and aridity) as well as presenting an opportunity for the use of a novel technique to examine the regional fire history. I processed and decontaminated all ice samples and aliquots (approximately 480 final samples) in Class 100 clean room conditions at the Byrd Polar Research Center (BPRC, Columbus, Ohio, USA) between 17 January 2010 and 1 February 2010. During February and March 2010, I quantified levoglucosan flux (1,6-anhydro-ß-D-glucopyranose) in 120 NIF2 ice samples using triple quadrupole tandem mass spectrometry. These results depict a comprehensive decadal to centennial history of African savanna fires over the past 4000 years, using levoglucosan as an atmospheric molecular tracer for biomass burning. I presented these results at five international conferences and one workshop. 2) Analysing trace elements in NIF2 We integrated the record of organic compounds in Kilimanjaro NIF2 with traditional ice-core analyses (ionic species and dust concentrations) to expand the current understanding of the climate system with implications for the global carbon cycle. I determined trace element concentrations in NIF2 aliquots during week-long measurement periods in April and July 2010 using a ThermoFischer Element2 High-resolution ICP-MS with an APEX desolvation system. These determinations were used as an initial investigation of trace-metal concentrations in Kilimanjaro NIF2 as well as for evaluating the repeatability and reliability of the instrumental measurement process. This work was presented at one international conference and forms the basis of our manuscript to be submitted to Environmental Science and Technology. 3) Expanding East African fire history records through examining levoglucosan and charcoal in lakes I sampled 600 lake core sediments from Lake Victoria (1°4'S, 33°1'E) and Lake Challa (located on the lower eastern slope of Mt. Kilimanjaro). I prepared the Lake Challa sediment samples at the University of Ghent, Belgium in May 2010 and obtained Lake Victoria samples from the University of Minnesota, USA in May and June 2010. I extracted and analysed levoglucosan from Lakes Victoria and Challa continuously throughout July, August and September 2010. This work has been expanded outside of the scope of this Marie Curie Fellowship and provides the primary work for a three-year PhD study (Torben Kirchegeorg) at the University of Venice, beginning in September 2011. In addition, I am collaborating with the University of Illinois, USA for charcoal analysis from the Lake Challa sediment core which provides a record of past fire activity in the Kilimanjaro region. I am currently writing a manuscript combining the Lake Challa charcoal records and the ice-core levoglucosan results. 4) Combining biomass burning proxy records with GCMs The deposition of aerosols on glacier surfaces depends on the general circulation patterns of the region. I am collaborating with Victor Brovkin, Tim Bruechner and Silvia Kloster from the Max Planck Institute, Hamburg, Germany to combine my measured levoglucosan data with the EPI-Earth System model.

Data: CORDIS, © European Union