To understand how our climate is changing today and what could happen in the future, we need to understand how the Earth’s climate has changed in the past. However, on a global scale, we have not been studying the Earth’s climate for very long.
To overcome this lack of recorded data, scientists turn to natural archives such as corals, which record past ocean temperatures and salinities in the chemistry of their skeletons and can live for centuries, providing much needed long-term climate records. The ratio of the element Strontium (Sr) to Calcium (Ca) in corals is directly related to the temperature and the Sr/Ca ratio of the seawater in which the coral lived. Seawater Sr/Ca is conventionally thought to be constant, but this may not be the case.
UMCES Chesapeake Biological Laboratory (CBL) scientists Drs. Johan Schijf and Hali Kilbourne have designed a research project to test this assumption. Their research will examine the stability of Sr/Ca ratios in seawater and assess the potential impacts of fluctuations in the ratio of Sr/Ca in seawater on reconstructions of past temperatures based on the ratio of Sr/Ca in coral skeletons. They will work with Agraj Khare, a graduate student studying for a Ph.D. in the Marine, Estuarine, and Environmental Sciences program at UMCES CBL, to carry out the three main components of the research.
The first component will be to develop the analytical method to be able to measure seawater Sr/Ca ratios quickly yet very precisely. Current methodologies are tedious and expensive, which is why there has been little previous work on this topic.
The second component will be to make many measurements of seawater Sr/Ca ratios from a variety of locations where Drs. Schijf and Kilbourne have previously sampled corals for paleo-temperature reconstructions, including the Florida Keys, US Virgin Islands, and British Virgin Islands. This project will greatly increase the number of precise measurements of the ratio of Sr/Ca in seawater globally.
The third and final component of this project will be quantifying the differing impacts of temperature and seawater Sr/Ca ratios on coral-based temperature reconstructions using measurements of temperature and seawater Sr/Ca ratios taken regularly over 2 years next to growing corals.
In the end, the team hopes to improve reconstructions of past climate to better inform projections of future climate change. Improved projections of future conditions could ultimately be used to help humans prepare and adapt to things like sea level rise and increased frequency and intensity of storms.
Want to learn more?
To learn more about CBL research related to corals and climate change, join us for the second Science for Citizens Seminar in our fall 2015 series, “Corals and Climate Change: Reconstructing the past to understand the future.” This free, public seminar will be presented by Dr. Kilbourne in CBL’s Bernie Fowler Laboratory on Tuesday, October 06, 2015 from 7:00 – 8:00pm.
Can’t make it to the seminar? Visit Dr. Kilbourne’s website to learn more about her research efforts
