A wide range of environmental information from both terrestrial and marine realms is required from palaeoclimate archives to better understand the climate system and to provide a palaeoclimatic context for predictions of future rates of climate change, impact and Earth system sensitivity. Overall, far less attention has been paid to terrestrial environments, compared to the marine realm, due to the paucity of ubiquitous biomarkers with quantitative palaeoclimatic utility.
For the first time we have recently found strong correlations between 3-hydroxy fatty acid (3-OH-FA) distributions, synthesised within Gram-negative bacterial membranes, and environmental parameters. Based on this discovery we have defined a number of new geochemical proxies, wherein 3-OH-FAs from Gram-negative bacteria quantitatively record the soil pH and mean annual temperature of their environment. The ubiquitous natural distribution of Gram-negative bacteria means that these novel and independent microbial biomarker based proxies for pH and temperature have huge potential for wide spread applicability in palaeoclimatic reconstructions from terrestrial and marine archives. This PhD project will explore the new avenues of research opened up by these new discoveries. Specifically:
- Production of new global and regional calibrations (based on soils, lake and marine sediments) to expand and refine the new proxies for pH and temperature.
- First applications of new proxies to a variety of palaeoclimate archives (ocean drilling sediment cores, lake sediments, speleothems) on a variety of time-scales (Holocene to Cenozoic).
- Collaboration with soil ecologist Dr Sabine Reinsch (CEH) and other CENTA partners. This work will explore, experimentally the influence of temperature, pH, soil microrganisms, nutrient status and CO2 on the 3-OH-FA proxies.
Geological work: Initial focus will be on developing empírical proxy calibrations for applications to marine and lake sediment cores. The student will work with the supervisors to compile a suitable collection of marine and lake surface samples from national and international repositories (i.e. The International Ocean Discovery Programme, BGS).
Experimental work: The project will explore the distributions of 3-OH-FAs in response to environmental changes in experimental plots. CEH monitoring sites in north-east Wales and the Peak District are used to study the effects of climate change within upland ecosystems, including soil microbes. This will be in collaboration with Dr Sabine Reinsch and colleagues at CEH and through utilistation of facilities at The Birmingham Institute of Forest Research (BIFoR)
All samples will be subjected to organic geochemical extraction and clean-up and analytical methods: i.e.
acid hydrolysis and digestion Wang et al., 2012), extraction with organic solvents, separation into chemical fractions and analysis by GC-FID, GC-MS.
Training and Skills
CENTA students will benefit from 45 days training throughout their PhD including a 10 day placement. In the first year, students will be trained as a single cohort on environmental science, research methods and core skills. Throughout the PhD, training will progress from core skills sets to master classes specific to the student's projects and themes.
This project will also provide detailed training in the geochemical methods necessary for 3-OH-FA analyses for environmental reconstructions, including organic geochemistry provided at the Birmingham and a visit to world leading China University of Geosciences in Wuhan. The DR will also receive training in the collection and interpretation of experimental data with colleagues at CEH.
This project will inevitably offer extensive networking opportunities with national and international scientists in addition to data handling and interpretation and scientific communication through writing, poster and oral presentations to academic and non-academic audiences.
Year 1: Obtain training in sample processing of soil and sediment sample material, organic geochemical techniques. Generate data surface sediment samples and derive new calibrations. Begin first phase of experimental plot sampling (including legacy samples).
Year 2: Visit Prof. Xie, Wuhan. Present results at a domestic (BOGS) or smaller international meeting (Gordon conference) and prepare manuscript. Prepare samples from palaeoclimate archives. Second phase of experimental plot sampling.
Year 3: Finish remaining analytical work, present results at an international conference. Write up results for final thesis and additional papers.
Partners and collaboration (including CASE)
Close collaboration between CENTA partners (UoB and CEH) is integral to this project. This project also benefits from external collaborations with scientists working on 3-OH-FAs. The PhD student will have excellent opportunities to collaborate internationally.
A research visit to work with Prof. Xie at the China University of Geosciences, Wuhan is of paramount importance. Prof. Xie’s group leads the world in the exciting development of 3-OH-FAs as paleoclimate proxies.
This project will build on a on-going coloration between the lead supervisor and Prof. Xie, who have successfully co-supervised a CSC PhD student (Canfa Wang) currently working on 3-OH-FAs (1 manuscript in review, 1 submitted, 2 in preparation).
Contact: Dr James Bendle
Telephone: +44 (0) 121 41 46156