Studentship: The magnitude and impacts of historic ocean acidification revealed by Boron isotope analysis of rhodolith-forming coralline algae

Location: University of Southampton, National Oceanography Centre Southampton, United Kingdom

Rationale:

Half of anthropogenic emissions of CO2 have been mixed into the ocean creating carbonic acid, causing a drop in ocean pH of ~0.1 units (Ocean Acidification, OA) and a decline in the saturation state of calcium carbonate (CaCO3). Determining exactly how marine organisms such as corals and coralline algae that build their skeletons from CaCO3 are impacted by this change is imperative, particularly since by the end of the 21st century pH is expected to drop by a further 0.3-0.5 units as the oceans continue to absorb ever growing CO2 emissions. One way to understand how marine calcifiers will be affected by future ocean acidification is to reconstruct how they have responded to historic acidification (e.g. [1]).  However, this approach is limited because open ocean seawater pH measurements have poor temporal and spatial coverage and the carbonate system in coastal environments is highly dynamic and even more poorly constrained.  This project will use the boron isotope-pH proxy (e.g. [2]) in rhodolith-forming coralline algae to directly quantify ocean acidification over the recent past (ca. 100 yrs) for several regions and couple this with measurements of rhodolith coralline algae calcification, to directly determine how acidification has already impacted these important species.

Methodology:

Rhodoliths are free-living, habitat-forming coralline algae found in the euphotic zone globally and they are important species to study for ocean acidification.  The aims of this project are to use tried and tested methods [2] to generate multiple annually resolved temporal records of d11B-derived pH from samples of coralline algae covering the last 100 years from a wide geographic range from the NHM collection (Shetland, Iceland, Scandinavia, Svalbard) and through new field work (UK and Bermuda).  These new records will then be used to quantify the magnitude of historic OA and identify the natural and long-term anthropogenic patterns of carbonate system change exhibited at each location (e.g. [3]). This will:

(1) shed light on the accuracy of models of the oceanic uptake of anthropogenic CO2;

(2) highlight natural cycles in local pH change in coastal regions that may exacerbate (or partially mitigate) future acidification; and

(3) when coupled with assessments of the temporal changes in algal calcification (through measurements of the skeleton micro-structure)[1], illuminate the impact of historic (last 100 years) acidification on this important species.

Training:

All doctoral candidates will enrol in the Graduate School of NOCS (GSNOCS), where they will receive specialist training in oral and written presentation skills, have the opportunity to participate in teaching activities, and have access to a full range of research and generic training opportunities. GSNOCS attracts students from all over the world and from all science and engineering backgrounds. There are currently around 200 full- and part-time PhD students enrolled (~60% UK and 40% EU & overseas).

The studentship is eligible for inclusion within the NERC SPITFIRE Doctoral Training Partnership (DTP). The SPITFIRE DTP programme provides comprehensive personal and professional development training alongside extensive opportunities for students to expand their multi-disciplinary outlook through interactions with a wide network of academic, research and industrial/policy partners. The student will be registered within the Graduate School of NOCS (GSNOCS). The successful candidate will carry out field work around the UK and in Bermuda to collect living samples of temperate and tropical coralline algae.  They will join Foster’s large, active research group specialising in boron geochemistry and will receive specialist training in state-of-the-art analytical skills in a world class geochemical facility, including boron isotope analysis by MC-ICPMS and analysis of Mg/Ca (and other trace elements) by Laser ablation and solution-mode ICPMS.  They also will receive training at the NHM in coralline algae molecular taxonomy, age model generation and calcification assessment using scanning electron microscopy.  The successful candidate will have the opportunity to present their work at several international conferences.

Wider Implications:

Understanding the magnitude of historic ocean pH change is limited to a handful of locations where continual measurements exist for the last 20-30 years [3].  Given this lack of measurements, proxy based pH reconstructions, particularly from the wide geographic coverage coralline algae offer, may prove invaluable in understanding the oceans’ role in taking up anthropogenic CO2.  The impact of ocean acidification on marine calcifiers is also of great importance and is subject to considerable investigation both in the UK and worldwide.  This is particularly the case for rhodoliths that provide key habitats for invertebrates and juvenile fish.   Ongoing research at the NHM and at UoS is central to the UK Ocean Acidification research effort (e.g. http://www.oceanacidification.org.uk).

Eligibility & Funding Details:

This SPITFIRE project is open to applicants who meet the SPITFIRE eligibility criteria, alongside other exceptional applicants.

Check your eligibility and find information on how to apply here.

UK applicants and EU students who meet the RCUK eligibility criteria please apply to SPITFIRE

Non SPITFIRE eligible applicants please apply to GSNOCS

Please make sure you apply to the correct programme as applications to SPITFIRE from non-eligible applicants will be rejected automatically.

More information.


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