Project Overview
Oceanic calcium carbonate production by microscopic marine organisms (foraminifera) is one of the most important long-term sinks of carbon on Earth’s surface. This project will determine the sensitivity of these organisms to ongoing climate change and ocean acidification and constrain whether their response will contribute to future CO2 emissions.
Project Description
Foraminifera produce around 30% of all calcium carbonate in the ocean, much of which is buried in marine sediments, locking carbon out of the ocean-atmosphere system. Conversely, calcification is an instantaneous source of protons, contributing to acidification. However, we do not know how foraminifera will respond on aggregate to ocean acidification, such that the extent to which the combination of these two processes will represent a positive or negative feedback on human-driven climate change is poorly constrained [1]. In this project, you will combine cutting-edge techniques in experimental laboratory culturing [2,3] and isotope geochemistry, and combine these new results with comparative data collected from unique historical museum collections. Specifically, you will:
- Determine the response of foraminifera calcification to the combined effects of ocean acidification and warming, working with species from various habitats and with different shell chemistries in both a temperate and tropical setting, constrained via the precise measurement of isotope labels incorporated into their shells.
- Compare these results to historic museum samples, collected before and during anthropogenic ocean acidification thus providing a real-world test of the experimental data. As part of this, you will visit Natural History Museum collections.
- Build these results into a global-scale box model of the response of foraminifera calcification to future climate change, informed by output from state-of-the-art climate models.
Ultimately, the project, with its extensive laboratory, museum, and fieldwork components, will determine how diverse species of foraminifera are likely to be impacted by ocean acidification over the coming century, and marry this data with climate model output to determine whether future changes in marine calcification are a positive carbon cycle feedback.
The INSPIRE 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 at the University of Southampton and hosted in the School of Ocean and Earth Science, which cohabits the National Oceanography Centre Southampton. Specific training will include:
- Extensive experience in laboratory culturing of marine organisms, including extended fieldwork periods.
- Techniques necessary to determine calcification rates (seawater carbonate chemistry measurements; CT scanning).
- Analytical geochemistry, including the operation of mass spectrometers.
- Experience working with museum collections.
- The development and application of numerical models, including the use of output from climate models.
- Proficiency in programming languages (Matlab/python/R) including for the purposes of building models of global calcification response.
- Quantitative and qualitative analytical skills.
- Scientific communication through multiple media and at various local, national, and international conferences/meetings.
[1] Ridgwell et al. (2009). From laboratory manipulations to Earth system models: scaling calcification impacts of ocean acidification. Biogeosciences, 6(11), 2611.
[2] Evans et al. (2015). Mg/Ca-temperature and seawater-test chemistry relationships in the shallow-dwelling large benthic foraminifera Operculina ammonoides. Geochimica et Cosmochimica Acta, 148, 325.
[3] Khanna, Godbold et al. (2013). The impact of ocean acidification on the functional morphology of foraminifera. PLoS One, 8(12), e83118.
