USAP-DC

This project uses radiocarbon in deep-sea corals to understand the Southern Ocean's role in modulating global climate. A key site of deep-water formation, the Southern Ocean is critical to exchange of heat and carbon between the deep-ocean and atmosphere. Changes in it may be linked to low atmospheric CO2 during the last glacial maximum through increased biologic carbon draw down or decreased air-sea CO2 exchange. Testing these hypotheses is challenging because of the scarcity of suitable records of the Southern Ocean's biogeochemistry and circulation. The aragonitic skeletons of deep-sea corals may offer insight because they are well suited for radiocarbon analyses-reflective of the 14C content of the past water column--while also allowing for timing of events through U-series age measurements. Overall, these measurements will put new constraints on the extent of air-sea gas exchange, polar water-column stratification, and the flux of Southern-sourced deep water to the rest of the world's oceans. As a part of this work, new sections of the Drake Passage sea floor will be mapped and imaged, along with the present and past distributions of deep-sea corals and their habitats.



A significant broader impact of this work is characterizing the functioning of what may be a key control of atmospheric CO2 content, which could prove important for fully understanding the impacts of continued CO2 emissions and developing mitigation strategies. As well, the work will characterize deep marine ecologies that are poorly understood, but increasingly exploited as fisheries resources.

Person	Role
Dalziel, Ian W.	Investigator

Antarctic Earth Sciences

Award # 0636787

NBP0805

None in the Database

Repository	Title (link)	Format(s)	Status
R2R	Expedition Data	None	exist

1. Struve, T., van de Flierdt, T., Burke, A., Robinson, L. F., Hammond, S. J., Crocket, K. C., … White, N. J. (2017). Neodymium isotopes and concentrations in aragonitic scleractinian cold-water coral skeletons - Modern calibration and evaluation of palaeo-applications. Chemical Geology, 453, 146–168. (doi:10.1016/j.chemgeo.2017.01.022)
2. Margolin, A. R., Robinson, L. F., Burke, A., Waller, R. G., Scanlon, K. M., Roberts, M. L., … van de Flierdt, T. (2014). Temporal and spatial distributions of cold-water corals in the Drake Passage: Insights from the last 35,000 years. Deep Sea Research Part II: Topical Studies in Oceanography, 99, 237–248. (doi:10.1016/j.dsr2.2013.06.008)
3. Samperiz, A., Robinson, L. F., Stewart, J. A., Strawson, I., Leng, M. J., Rosenheim, B. E., … Santodomingo, N. (2020). Stylasterid corals: A new paleotemperature archive. Earth and Planetary Science Letters, 545, 116407. (doi:10.1016/j.epsl.2020.116407)