World-Leading St Andrews Scholarship in Earth Sciences and Chemistry

Страна: Великобритания;

Дедлайн: 16.01.2020

Веб-сайт: st-andrews.ac.uk

 

The University of St Andrews is pleased to offer a full scholarship funded by St Leonard’s Postgraduate College, to support an exceptional student undertaking doctoral research in the following project:

The Roles of Lipids in Coral Biomineralisation and the Effects of Future Climate Change

Project description

Coral reefs are among the most biologically diverse ecosystems and are of substantial economic importance in terms of fisheries, tourism and coastal protection. Understanding the coral biomineralisation process is key to predicting the impacts of increasing seawater temperatures and pCO2 (e.g. ocean acidification) on future reef development. To date, most research in this field has explored how anthropogenic changes in seawater affect the precipitation of aragonite, the calcium carbonate mineral used to build the coral skeleton. However coral skeletons are composite materials composed of both aragonite and organic materials including proteins, sugars and lipids. Very little is known about the roles of biomolecules in the precipitation process or how these will be affected by climate change.

This doctoral project will identify the roles of lipids in coral biomineralisation and determine how these will be affected by future climate change. Skeletal lipids are dominated by sterols and phospholipids and the latter may bind Ca2+ and act as templates for CaCO3 deposition. Lipids extracted from coral skeletons affect the crystal morphology and porosity of calcite (a second form of calcium carbonate) precipitated in vitro but the molecules responsible for this are unresolved.

Key study objectives are to:

  1. Investigate how skeletal lipids affect aragonite precipitation. The student will use apparatus in Dr Allison’s lab to precipitate aragonites in vitro under tightly controlled conditions. They will determine how different lipids affect the growth rate and crystal morphology of aragonite. The student will develop methods to deposit the lipids for study on the starting aragonite seed crystals and to ensure that they remain stable during the precipitation. Similar techniques have been developed in bone research but are yet to be applied in the broader biomineralisation field.
  2. Determine how skeletal lipids respond to future climate change. Our preliminary experiments indicate that the lipid composition of the coral tissues is affected by seawater pCO2. The student will determine quantitatively how the lipid compositions of coral skeletons are affected by both increasing seawater pCO2 and temperature using the coral samples cultured previously. Skeletal lipids will be extracted and the concentrations of specific lipid species determined by electrospray tandem mass spectrometry and gas chromatography mass spectrometry in Dr Smith’s lab.
  3. Predict how future climate change will affect the roles of lipids in biomineralisation. The student will precipitate aragonite in vitro under conditions inferred to occur at the coral calcification site in the present day and under future climate change. Both the pH and dissolved inorganic chemistry of the fluid at the coral calcification site decrease under future climate scenarios. These changes influence how other biomolecules, e.g. amino acids, affect aragonite precipitation. The student will alter the seawater chemistry and the concentrations and composition of lipids to reflect that observed in coral skeletons under future climate scenarios and will determine how these changes affect biomineralisation.

This project will determine how lipids influence aragonite precipitation and will identify how future climate change will affect the lipid role in tropical corals. The results of the study will have applications across a range of marine calcareous organisms.

The successful candidate will be supervised by Dr Nicola Allison and Professor Terry Smith and based in the School of Earth and Environmental Sciences and the School of Chemistry.

 

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