‘Organics in ice’: Novel organic compounds in ice cores for use in palaeoclimate reconstruction

• Main Author: King, Amy Constance Faith
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Selwyn 2019
• Subjects: Ice core; Biomarkers; Mass Spectrometry; Liquid Chromotography; Palaeoclimate; Bouvet; Sea Ice; Belukha; Greenland; Monte Rosa; ice core; Sea ice; Alaska
• Online Access: https://doi.org/10.17863/CAM.44710; https://www.repository.cam.ac.uk/handle/1810/297656

The majority of current ice core studies focus on analysing the inorganic component of atmospheric aerosol, trapped and preserved in the ice as a record of past atmosphere. However, this does not fully represent the make-up of atmospheric aerosol, which can be up to 50% organic. This thesis aims to develop the understanding and quantification of a number of these organic compounds in ice core samples. A novel and promising area of ‘organics in ice’ research lies within the groups of primary and secondary compounds released from the terrestrial and marine biospheres; these compounds may help us to form a record of past biosphere emissions, with implications for biological productivity and atmospheric chemistry. A small selection of studies obtaining new records from these types of organic compounds in ice have demonstrated this concept, for example lipid compounds in snow layers dating back 450 years in Greenland, oxidation products of isoprene and monoterpenes in ice up to 350 years old in Alaska, and carboxylic acids and inorganic ions between 1942-1993 from Grenzgletscher (Monte Rosa Massif) in the southern Swiss Alps. Compound concentrations were related back to Northern Hemisphere temperature, atmospheric transport pathways and intensities, and biomass burning signals respectively. There are many terrestrial and marine biogenic compounds not yet investigated in ice core samples. Thus we are presented with an almost untapped reservoir of new climate information. Therefore, it is timely to produce a method of analysis for a long list of the most promising of these compounds (herein ‘target compounds’), namely fatty acids and secondary oxidation aerosol of terpenes (SOA), allowing quantification of these novel analytes in ice core samples to investigate the concept further. This project begins with an investigation in to the possible contamination sources of the target compounds in ice core samples. It attempts to quantify the threat of contamination throughout the drilling, storage and analyses processes. It ...