Utilising Fourier-transform Infrared (FTIR) spectroscopy for the characterisation of intertidal sediments

Intertidal sediments are physically and biologically dynamic, forming complex ecosystems that are historically attractive to human settlement. Estuaries, for example, provide an extensive range of processes and functions known as ecosystem services that can be regarded as beneficial, or even essential, to humans. Ecosystem services provided by estuaries include flood mitigation, biodiversity provisioning, fisheries, aquaculture, agriculture, primary production, carbon storage, cultural heritage and recreation. Despite their value, historical and modern detrimental practices by humans have exposed these habitats to “multiple and escalating pressures” resulting in significant habitat decline. The urgency in addressing estuarine ecosystem management has been renewed under global climate change scenarios. This goal can only be supported by the understanding of the ecosystem services delivered by depositional systems and their sediments.

This project will develop and use sate of the art spectrophotometric techniques to address research questions about the status of different estuarine systems. This research has environmental and industrial impact to identify and quantify constituents of intertidal sediments that drive sediment characteristics and behaviour that are key to coastal management practices. These include extracellular polymeric substance, mineralogy and organic matter, which can all be characterised using FTIR. The ability to rapidly characterise physical and biological properties of sediments, especially if this can be achieved in-situ, will be a significant contribution to all fields of estuarine and coastal science reseach.

Project Aims
The primary aim of the project is to characterise the anthropogenic pressure on estuarine systems using state of the art monitoring for intertidal and coastal sediments. New techniques allowing for the rapid and reliable in-situ collection of spectra from sediments using portable FTIR technology will be developed and applied. The ultimate aim of the project will be to improve monitoring capabilities, future management and prediction of change trajectory for coastal management.

Project Outline
1-4 months: A literature search will be conducted to review the status of FTIR characterisation of soils and sediments. Recent developments in FTIR technology have resulted in an influx of research articles, where FTIR spectra have been unintentionally misinterpreted, and provides an opportunity for critical review. 5-12 months: Novel methodologies for the analysis of fresh and in-situ sediments using the Exoscan Portable FTIR (Agilent) will be developed. Initially, the suitability of the two approaches for FTIR analysis (Attenuated Total Reflectance and Diffuse Reflectance) will be compared, followed by the optimisation of measurement parameters to overcome challenges of in-situ sediment. These challenges include distortion of spectra by variation in particle size and water content of intertidal sediments. 12-18 months: Spectral analysis software will be used to calibrate predictive models for the measurement of key sediment constituents. The archive of intertidal sediments will be used for calibration and testing, in addition to the spiking of sediments with known material. 18+ months: With the development of the new techniques, large- scale, high-resolution sampling campaigns will be possible across one or several estuaries, assessing the status of anthropogenic pressures and management strategies. Student Input: The student will be encouraged to direct their own research in order to explore the utility of rapid sediment characterisation in relation to ecosystem services. For example, the tracking of sediments prone to biological or chemical contaminants, or characterising organic matter and mineralogy with relation to sediment stability.

The student will develop a thorough understanding of spectroscopic methods and techniques through working in a UKAS accredited Lab and as a result of the method development aspects of the project. They will become familiar with a range of technical software for the analysis of spectra, and develop a strong knowledge of statistical models within these programs for the initial analysis of spectra, but also in predictive modelling of key sediment properties from spectral data. These, combined with an understanding of traditional biochemical and physical analyses applicable to a large range of environmental samples, will provide a strong basis for careers in analytical sciences and spectroscopy. With the student registered at the University of St Andrews, they will become part of the Marine Alliance for Science and Technology for Scotland (MASTS), where they join a cohort of Scottish marine researchers and have the opportunity to present at the MASTS ASM. They will also join the MASTS graduate school that provides the opportunity to complete the ‘MASTS Postgraduate Certificate in Researcher Professional Development’.

Informal enquiries should be directed to Dr Jean Robertson (The James Hutton Institute): [Email Address Removed], or Prof David Paterson (University of St Andrews): [Email Address Removed].