Quantitative Diatom data collected from the 2017 RV Investigator voyage, IN2017_V01

Diatom data from IN2017_V01: These data were generated by Amy Leventer (aleventer@colgate.edu) and undergraduate students at Colgate University, including Isabel Dove, Meghan Duffy, and Meaghan Kendall. All questions regarding the specifics of these data should be directed to Amy Leventer. These data are based on samples collected during research cruise IN2017_V01 of the RV Investigator, co-chief scientists, Leanne Armand and Phil O’Brien. The IN2017-V01post-cruise report is available through open access via the e-document portal through the ANU library. https://openresearch-repository.anu.edu.au/handle/1885/142525 The document DOI: 10.4225/13/5acea64c48693 The preferred citation is: L.K. Armand, P.E. O’Brien and On-board Scientific Party. 2018. Interactions of the Totten Glacier with the Southern Ocean through multiple glacial cycles (IN2017-V01): Post-survey report, Research School of Earth Sciences, Australian National University: Canberra, http://dx.doi.org/10.4225/13/5acea64c48693 Samples for diatom analysis were collected on board ship immediately after core recovery. Samples were dried in an oven at 50 degrees C prior to analytical work. Quantitative diatom slides were prepared according to the settling technique of Warnock and Scherer (2014). Cover slips were adhered to the slides using Norland Optical Adhesive #61. Slides were observed under Olympus CX31, BX50 and BX60, and Zeiss Primo Star light microscopes, using a 100X oil immersion objective for a total magnification of 1000X. A minimum of 400 valves or 10 transects was counted for each slide, depending on the absolute diatom abundance. Interglacial samples were relatively diatom-rich, consequently counts of 400 specimens were possible. However, most glacial samples were diatom-poor, making it very difficult and time-consuming to count 400 specimens. Under these conditions, 10 transects were counted, as has been done in previous studies of sediments with very low diatom concentrations (Rebesco et al., 2014). Valves were only counted if greaster than 50% complete. Diatoms were identified to species level when possible (Crosta et al., 2005; Armand et al., 2005; Cefarelli et al., 2010). Occurrences of biostratigraphic markers were noted and tallied concurrently. Species were considered extinct when observed stratigraphically higher than extinction boundaries as identified by Cody et al. (2008). Station_core Longitude Latitude A005_KC02_PC01 115.623 -64.471 A006_KC03 115.043 -64.463 A042_KC14 116.6403 -64.5387 C012_KC04_PC05 119.3012 -64.675 C013_KC05 119.0183 -64.6538 C015_KC06 118.696 -64.729 C018_KC07 118.498 -64.401 C020_KC08 119.739 -64.794 C022_KC11 120.049 -65.1313 C025_KC12_PC08 120.8635 -64.9538 C038_KC13 119.1035 -64.4828 Armand, L.K., X. Crosta, O. Romero, J. J. Pichon (2005), The biogeography of major diatom taxa in Southern Ocean sediments: 1. Sea ice related species, Paleogeography, Paleoclimatology, Paleoecology, 223, 93-126. Cefarelli, A.O., M. E. Ferrario, G. O. Almandoz, A. G. Atencio, R. Akselman, M. Vernet (2010), Diversity of the diatom genus Fragilariopsis in the Argentine Sea and Antarctic waters: morphology, distribution and abundance, Polar Biology, 33(2), 1463-1484. Cody, R., R. H. Levy, D. M. Harwood, P. M. Sadler (2008), Thinking outside the zone: High-resolution quantitative diatom biochronology for the Antarctic Neogene, Palaeogeography, Palaeoclimatology, Palaeoecology, 260, 92-121, doi:10.1016/j.palaeo.2007.08.020 Crosta, X., O. Romero, L. K. Armand, J. Pichon (2005), The biogeography of major diatom taxa in Southern Ocean sediments: 2. Open ocean related species, Palaeogeography, Palaeoclimatology, Palaeoecology, 223, 66-92. Rebesco, M., E. Domack, F. Zgur, C. Lavoie, A. Leventer, S. Brachfeld, V. Willmott, G. Halverson, M. Truffer, T. Scambos, J. Smith, E. Pettit (2014), Boundary condition of grounding lines prior to collapse, Larson-B Ice Shelf, Antarctica, Science, 345, 1354-1358. Warnock, J. P., R. P. Scherer (2014), A revised method for determining the absolute abundance of diatoms, J. Paleolimnol., doi:10.1007/s10933-014-9808-0 These data were collected to provide paleoceanographic and biostratigraphic information. Amy Leventer, Isabel Dove, Meghan Duffy, and Meaghan Kendall unpublished data