I recently began my role as a Stable Isotope Research Assistant at the NERC National Environmental Isotope Facility at the BGS headquarters in Keyworth, Nottingham. Prior to working at the BGS, I studied for a PhD at Imperial College London. My thesis focussed on the zinc and cadmium stable isotope compositions of igneous rocks and meteorites to better understand how Earth obtained volatile elements and species such as water. During this time, I gained valuable knowledge and experience in understanding different isotope systems, mass spectrometry, as well as sample preparation and laboratory techniques, all of which helped me to hit the ground running when starting my new role at the BGS.
My first few months have mainly involved analysing the carbon and oxygen stable isotope compositions of various carbonate samples, for example from lake sediments, as part of the Environmental Change, Adaptation and Resilience challenge area. This provides useful insight into how the environment in which these sediments were deposited changed over time and allows scientists to better understand the processes affecting similar environmental systems today.
Preparation of these sediments usually involves treatment with a dilute bleach solution overnight to remove unwanted organic material that may interfere with the isotope analysis. Each sample is then rinsed through with clean water before being crushed into a fine powder and weighed precisely. I have also gained additional experience in preparation of organic samples through acid digestion and freeze-drying techniques.
A lot of my time at the BGS has been spent using the carbonate line, a series of glass tubes and valves used to pump out air from bespoke sample vials to keep them under vacuum. This improves the accuracy of our isotope measurements by reducing any interference from unwanted atmospheric gases during analysis. Once under vacuum, each carbonate sample is reacted with phosphoric acid to produce CO2 gas. This gas is then extracted using the carbonate line, which has given me my first experience in using liquid nitrogen in the lab.
With the help of Dr Jack Lacey, I recently began independently analysing the isotope compositions of these samples using a newly acquired gas source mass spectrometer. Jack and I have also spent time carrying out test runs on this instrument to check that it is operating at an acceptable level of accuracy and precision, as well as experimenting to identify the optimal technique for analysing the oxygen isotope composition of sediments containing low concentrations of siderite (an iron carbonate mineral). With time, I hope to gain further experience using additional isotope systems and techniques.
Outside of the laboratory, I have also taken part in some BGS Wilding Group events, helping to plant trees and build insect hotels, with the aim of increasing biodiversity here at the Keyworth site. I have thoroughly enjoyed my time spent in the lab and learning these new techniques, as well as collaborating with people both from the BGS and other institutions, and look forward to developing my skills further over the coming year.
Harvey Pickard – Pickard Harvey – British Geological Survey (bgs.ac.uk)