Chlorin concentrations measured in sediment samples collected during the IN2017-V01 voyage of the RV Investigator

Sediment cores were collected from the East Antarctic margin, aboard the Australian Marine National Facility R/V Investigator, during the IN2017_V01 voyage from January 14th to March 5th 2017 (Armand et al., 2018). This marine geoscience expedition, named the “Sabrina Sea Floor Survey”, focused notably on studying the interactions of the Totten Glacier with the Southern Ocean through multiple glacial cycles. The cores were collected using a multi-corer (MC) and a Kasten corer (KC). The MC were sliced every centimetre, wrapped up in plastic bags, and stored in the fridge. The KC was sub-sampled using a u-channel; and sliced every centimetre once back the home laboratory (IMAS, UTAS, Hobart, Australia).About 200 mg of sediment were dried in an oven at 40°C, ground using a pestle and a mortar and weighed into centrifuge tube. Chlorin (degradation products of chlorophyll-a) was extracted by sonication with acetone (90%; HPLC grade) following Schubert et al., (2005). Sample fluorescence was measured in triplicate by spectrofluorometry, at the excitation wavelength of 428 nm and the emission wavelength of 671 nm. The chlorin concentration was measured as followed:[chlorin] = F/C x 0.000015 / (S/1000)Where [chlorin] is the chlorin concentration in µg/g; F is the averaged fluorimetry intensity; C is the spectrofluorometer constant 1287.9; and S is the sediment weight in mg.ReferencesArmand, L. K., O’Brien, P. E., Armbrecht, L., Baker, H., Caburlotto, A., Connell, T., … Young, A. (2018). Interactions of the Totten Glacier with the Southern Ocean through multiple glacial cycles (IN2017-V01): Post-survey report. ANU Research Publications, (March). https://doi.org/http://dx.doi.org/10.4225/13/5acea64c48693Schubert, C. J., Niggemann, J., Klockgether, G., and Ferdelman, T. G. (2005). Chlorin Index: A new parameter for organic matter freshness in sediments. Geochemistry, Geophysics, Geosystems, 6(3). https://doi.org/10.1029/2004GC000837