Accurate reconstruction of SSTs from coral skeletal Sr/Ca: understanding Sr and Ca transport across coral tissues
Lead Research Organisation:
University of St Andrews
Department Name: Earth and Environmental Sciences
Abstract
The chemistry of coral skeletons records climatic information at the time the coral lived i.e. skeletal Sr/Ca is affected by seawater temperature. The analysis of fossil coral skeletons offers an excellent opportunity to reconstruct past ocean temperatures and therefore to predict past climates. However skeletal Sr/Ca is also affected by biological processes and corals of different growth rates deposit different skeletal Sr/Ca equating to errors in reconstructed seawater temperature of up to ~3 degrees C. In this research we will identify the cause of the Sr/Ca variations between fast and slow growing corals. We have devised a research programme to study how Sr and Ca are transported across the coral tissue to the calcification site. We will culture corals and use biochemical inhibitors to switch off various ion transport mechanisms to determine how skeletal chemistry is affected. We will identify how each mechanism varies between fast and slow growing corals and will develop a methodology to correct for variations in ion transport processes between corals, allowing the accurate reconstruction of SSTs from skeletal Sr/Ca.
Publications
Allison N
(2014)
Corals concentrate dissolved inorganic carbon to facilitate calcification.
in Nature communications
Allison N
(2011)
Controls on Sr/Ca and Mg/Ca in scleractinian corals: The effects of Ca-ATPase and transcellular Ca channels on skeletal chemistry
in Geochimica et Cosmochimica Acta
Allison N
(2010)
The potential origins and palaeoenvironmental implications of high temporal resolution d18O heterogeneity in coral skeletons
in Geochimica et Cosmochimica Acta
Allison N
(2010)
d11B, Sr, Mg and B in a modern Porites coral: the relationship between calcification site pH and skeletal chemistry
in Geochimica et Cosmochimica Acta
Allison N
(2013)
SIMS sputtering rates in biogenic aragonite: implications for culture calibration studies for palaeoenvironmental reconstruction SIMS sputtering rates in biogenic aragonite
in Surface and Interface Analysis
Finch A
(2010)
Ba XAFS in Ba-rich standard minerals and the potential for determining Ba structural state in calcium carbonate
in Chemical Geology
Kellock C
(2020)
The role of aspartic acid in reducing coral calcification under ocean acidification conditions.
in Scientific reports
| Description | Coral Sr/Ca is a commonly used palaeothermometer and the The Sr/Ca of fossil corals skeletons has been used to infer the sea surface temperatures at the time the coral grew. Analysis of fossils may indicate the glacial-interglacial temperature change and the amplitude and frequency of interdecadal climate events e.g. El Nino. In this project we tested how ion transport processes in the coral affect the Sr/Ca of the skeleton. We found that transcellular Ca ion transport did not affect the Sr/Ca geochemistry of coral skeletons indicating that changes in the activities of Ca-ATPase and Ca-channels do not generate Sr/Ca variations within or between corals. |
| Exploitation Route | Our findings indicate that changes in ion transport in corals are not responsible for the Sr/Ca variations observed between corals. The origin of these variations is still unknown. |
| Sectors | Environment |
| Description | MASTS visiting fellowship scheme |
| Amount | £2,806 (GBP) |
| Funding ID | VF64 |
| Organisation | Marine Alliance for Science and Technology for Scotland |
| Sector | Academic/University |
| Country | United Kingdom |
| Start | 12/2015 |
| End | 10/2016 |
| Description | Research collaboration with Prof Jonathan Erez, Hebrew University of Jerusalem |
| Organisation | Hebrew University of Jerusalem |
| Country | Israel |
| Sector | Academic/University |
| PI Contribution | In 2009 Allison worked in Erez's lab learning coral culturing and conducting experiments with biological calcium transport inhibitors to determine for Ca transport affects the chemistry of coal skeletons.. My research team provided chemicals for coral culturing and analysed the coral skeletal chemistry. In 2018, Allison again visited erez's lab to learn skills in confocal microscopy for imaging coral biomineralisation and for measuring pH at the coral calcification site using fluorescent pH sensitive dyes. |
| Collaborator Contribution | Erez provided the coral culturing facilities, grew the corals before the experiments and provided consumables and equipment for seawater monitoring. |
| Impact | This collaboration is multi disciplinary combining biology (biological transport of ions in corals), chemistry (seawater chemistry) and earth sciences (coral skeletal chemistry and morphology). This research has been reported in Geochimica et Cosmochimica Acta (2011) and Nature Communications (2014). |
| Start Year | 2009 |
| Description | Biomineralisation lecture to sutton trust students |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | National |
| Primary Audience | Other audiences |
| Results and Impact | A lecture/workshop on biomineralisation to Sutton Trust students (typically aged 17, these are school children from underprivileged backgrounds). These workshops are designed to encourage students to consider applying to university. |
| Year(s) Of Engagement Activity | 2014,2015,2016 |
| Description | Talk to Operation Wallacea participants in Honduras |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Undergraduate students |
| Results and Impact | A talk to Operation Wallacea participants in Honduras. This generated debate over the effects of climate change on coral reef development. |
| Year(s) Of Engagement Activity | 2016 |
| Description | Talk/lab visit to adult education students |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | Local |
| Primary Audience | Other audiences |
| Results and Impact | Talk and lab visit with a group of adult education students studying a geology course with a local tutor |
| Year(s) Of Engagement Activity | 2014 |