Effect of elevated temperature on Acropora pulchra exometabolome

Lead Supervisor: Dr. Miriam Reverter

Location: University of Plymouth, School of Biological and Marine Sciences

Duration: 6 weeks 

Suitable undergraduate degrees: Marine Biology, Biological Sciences, Marine and Environmental Sciences

Project background

Metabolites (i.e., small chemicals produced by living organisms) are one of the most universal “languages” in nature, central to ecosystem functions like nutrient cycling and chemical communication. Whilst the study of endometabolomomes (i.e., metabolites within an organism) has enabled elucidation of individual responses to biotic and abiotic factors, the very recent development of exometabolomics (i.e. the study of metabolites excreted by the organisms into the environment) opens exciting opportunities in community and conservation ecology. This project will study the potential of exometabolomes as a non-invasive tool to study coral physiology and responses to stress. The student will explore the responses of the hard coral Acropora pulchra exometabolome exposed to elevated temperature (31.7 °C) for 7 days, in comparison to the exometabolome of A. pulchra kept at ambient temperature (28°C). A. pulchra is a widespread branching scleractinian coral, that often dominates shallow back reef environments, creating a complex framework that supports many shallow coral reef species (i.e. juvenile fishes, invertebrates, etc.). Recent research has shown that despite the local importance of A. pulchra in habitat-creating, this species is highly sensitive to increased temperatures and is often amongst the first to bleach in back reefs.

This research aims to 1) showcase the use of a non-invasive tool (i.e. exometabolomes) to study the responses of A. pulchra to a short-term thermal stress and 2) bring new understanding on the metabolic mechanisms elicited by a short-term thermal stress on A. pulchra.

The short-term thermal experiment was conducted at the Centre of Island Research and Environmental Observatory (CRIOBE, Moorea, French Polynesia) in February 2023. A. pulchra exometabolomes (n = 10/treatment, ntotal=20) were captured by incubating coral colonies in 1 L of filtered seawater for 3 hours, and then filtered through a Solid-Phase Extraction (SPE) cartridge. The work will involve extracting the exometabolomes (desorb the exometabolites from the SPE cartriges) and analysing them by Liquid Chromatography coupled to Mass Spectrometry using a suitable untargeted metabolomics design. After data acquisition, the student will pre-process the data using specialised softwares (e.g. XCMS) to obtain a matrix of metabolic features and relative abundance/per sample. The data will then be analysed using different multivariate and univariate statistical tools to investigate the exometabolome differences between A. pulchra subjected to ambient temperature conditions and A. pulchra subjected to elevated temperature.
Overall, this project will allow the student to acquire first-hand research experience on a topic within the NERC remit. The student will not only be trained in diverse cutting-edge techniques but will learn to interpret and evaluate data results critically and will be encouraged to gain skills to work independently.