Hostname: page-component-cd9895bd7-p9bg8 Total loading time: 0 Render date: 2024-12-26T07:01:46.854Z Has data issue: false hasContentIssue false
  • English
  • Français

Holocene glacier fluctuations and environmental changes in subantarctic South Georgia inferred from a sediment record from a coastal inlet

Published online by Cambridge University Press:  30 October 2018

Sonja Berg ,
Duanne A. White ,
Sandra Jivcov ,
Martin Melles ,
Melanie J. Leng ,
Janet Rethemeyer ,
Claire Allen ,
Bianca Perren ,
Ole Bennike  and
Finn Viehberg
Sonja Berg*
Affiliation:
Institute of Geology and Mineralogy, University of Cologne, 50674 Cologne, Germany
Duanne A. White
Affiliation:
Institute for Applied Ecology, University of Canberra, Canberra, Australian Capital Territory 2601, Australia
Sandra Jivcov
Affiliation:
Institute of Geology and Mineralogy, University of Cologne, 50674 Cologne, Germany
Martin Melles
Affiliation:
Institute of Geology and Mineralogy, University of Cologne, 50674 Cologne, Germany
Melanie J. Leng
Affiliation:
NERC Isotopes Geosciences Facilities, British Geological Survey, Keyworth, Nottingham NG12 5GG, United Kingdom School of Biosciences, Centre for Environmental Geochemistry, The University of Nottingham, Sutton Bonington Campus, Leicestershire LE12 5RD, United Kingdom
Janet Rethemeyer
Affiliation:
Institute of Geology and Mineralogy, University of Cologne, 50674 Cologne, Germany
Claire Allen
Affiliation:
British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, United Kingdom
Bianca Perren
Affiliation:
British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, United Kingdom
Ole Bennike
Affiliation:
Geological Survey of Denmark and Greenland, Øster Voldgade 10, 1350Copenhagen, Denmark
Finn Viehberg
Affiliation:
Institute of Geology and Mineralogy, University of Cologne, 50674 Cologne, Germany
*
*Corresponding author at: Institute of Geology and Mineralogy, University of Cologne, Zuelpicher Strasse 49a, 50674 Cologne, Germany. E-mail address: sberg0@uni-koeln.de (S. Berg).
Get access Rights & Permissions [Opens in a new window]

Abstract

The subantarctic island of South Georgia provides terrestrial and coastal marine records of climate variability, which are crucial for the understanding of the drivers of Holocene climate changes in the subantarctic region. Here we investigate a sediment core (Co1305) from a coastal inlet on South Georgia using elemental, lipid biomarker, diatom, and stable isotope data to infer changes in environmental conditions and to constrain the timing of late-glacial and Holocene glacier fluctuations. Because of the scarcity of terrestrial macrofossils and the presence of redeposited and relict organic matter in the sediments, age control for the record was obtained by compound-specific radiocarbon dating of mostly marine-derived n-C16 fatty acids. A basal till layer recovered in Little Jason Lagoon was likely deposited during an advance of local glaciers during the Antarctic cold reversal. After glacier retreat, an oligotrophic lake occupied the site, which transitioned to a marine inlet around 8.0±0.9 ka because of relative sea-level rise. From 7.0±0.6 to 4.0±0.4 ka, reduced vegetation coverage in the catchment, as well as high siliciclastic input and deposition of ice-rafted debris, indicates glacier advances in the terrestrial catchment and likely in the adjacent fjord. A second, less extensive period of glacier advances occurred in the late Holocene, after 1.8±0.3 ka.

Keywords

South GeorgiaHoloceneGlacier advanceCompound-specific radiocarbon analysisMarine sedimentsRelative sea level
Type
Research Article
Information
Quaternary Research , Volume 91 , Issue 1 , January 2019 , pp. 132 - 148
Copyright
Copyright © University of Washington. Published by Cambridge University Press, 2018. 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Al-Handal, A.Y., Wulff, A., 2008a. Marine benthic diatoms from Potter Cove, King George Island, Antarctica. Botanica Marina 51, 51–68.Google Scholar
Al-Handal, A.Y., Wulff, A., 2008b. Marine epiphytic diatoms from the shallow sublittoral zone in Potter Cove, King George Island, Antarctica. Botanica Marina 51, 411–435.Google Scholar
Andersson, R.A., Meyers, P.A., 2012. Effect of climate change on the delivery and degradation of lipid biomarkers in a Holocene peat sequence in the Eastern European Russian Arctic. Organic Geochemistry 53, 63–72.Google Scholar
Angst, G., John, S., Mueller, C.W., Kögel-Knabner, I., Rethemeyer, J., 2016. Tracing the sources and spatial distribution of organic carbon in subsoils using a multi-biomarker approach. Scientific Reports 6, 29478.Google Scholar
Barlow, N.L.M., Bentley, M.J., Spada, G., Evans, D.J., Hansom, J.D., Brader, M.D., White, D.A., Zander, A., Berg, S., 2016. Testing models of ice cap extent, South Georgia, sub-Antarctic. Quaternary Science Reviews 154, 157–168.Google Scholar
Bentley, M.J., Evans, D.J.A., Fogwill, C.J., Hansom, J.D., Sugden, D.E., Kubik, P.W., 2007. Glacial geomorphology and chronology of deglaciation, South Georgia, sub-Antarctic. Quaternary Science Reviews 26, 644–677.Google Scholar
Bentley, M.J., Hodgson, D.A., Smith, J.A., O’Cofaigh, C., Domack, E.W., Larter, R.D., Roberts, S.J., et al., 2009. Mechanisms of Holocene palaeoenvironmental change in the Antarctic Peninsula region. Holocene 19, 51–69.Google Scholar
Blaaw, M., 2010. Methods and code for “classical” age-modelling of radiocarbon sequences. Quaternary Geochronology 5, 512–518.Google Scholar
Borchers, B., Marrero, S., Balco, G., Caffee, M., Goehring, B., Lifton, N., Nishiizumi, K., Phillips, F., Schaefer, J., Stone, J., 2016. Geochronological calibration of spallation production rates in the CRONUS-Earth project. Quaternary Geochronology 31, 188–198.Google Scholar
Clapperton, C.M., 1990. Quaternary glaciations in the Southern Ocean and Antarctic Peninsula area. Quaternary Science Reviews 9, 229–252.Google Scholar
Clapperton, C.M., Sugden, D.E., Birnie, J., Wilson, M.J., 1989. Late-glacial and Holocene glacier fluctuations and environmental change on South Georgia, Southern Ocean. Quaternary Research 31, 210–228.Google Scholar
Croudace, I.W., Rindby, A., Rothwell, R.G., 2006. ITRAX: description and evaluation of a new multi-function X-ray core scanner. In: Rothwell, R.G. (Ed.), New Techniques in Sediment Core Analysis. Geological Society, London, Special Publications 267, 51–63.Google Scholar
Dewald, A., Heinze, S., Jolie, J., Zilges, A., Dunai, T., Rethemeyer, J., Melles, M., et al., 2013. CologneAMS, a dedicated centre for accelerator mass spectrometry in Germany. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 294, 18–23.Google Scholar
Drenzek, N.J., Montucon, D.B., Yunker, M.B., Macdonald, R.W., Eglinton, T.I., 2007. Constraints on the origin of sedimentary organic carbon in the Beaufort Sea from coupled molecular 13C and 14C measurements. Marine Chemistry 103, 146–162.Google Scholar
Eglinton, G., Hamilton, R.J., 1963. The distribution of Alkanes. In: Swain, T. (Ed.), Chemical Plant Taxonomy. Academic Press, New York, pp. 187–217.Google Scholar
Eyles, N., Mullins, H.T., Hine, A.C., 1991. The seismic stratigraphy of Okanagan Lake, British Columbia: a record of rapid deglaciation in a deep “fjord-lake” basin. Sedimentary Geology 73, 13–41.Google Scholar
Favier, V., Verfaillie, D., Berthier, E., Menegoz, M., Jomelli, V., Kay, J.E., Ducret, L., et al. 2016. Atmospheric drying as the main driver of dramatic glacier wastage in the southern Indian Ocean. Scientific Reports 6, 32396.Google Scholar
Foster, L.C., Pearson, E.J., Juggins, S., Hodgson, D.A., Saunders, K.M., Verleyen, E., Roberts, S.J., 2016. Development of a regional glycerol dialkyl glycol tetraether (GDGT)–temperature calibration for Antarctic and sub-Antarctic lakes. Earth and Planetary Science Letters 433, 370–379.Google Scholar
Geprägs, P., Torres, M.E., Mau, S., Kasten, S., Römer, M., Bohrmann, G., 2016. Carbon cycling fed by methane seepage at the shallow Cumberland Bay, South Georgia, sub-Antarctic. Geochemistry, Geophysics, Geosystems 17, 1401–1418.Google Scholar
Gordon, J.E., 1987. Radiocarbon dates from the Nordenskjöld Glacier, South Georgia, and their implications for late Holocene glacier chronology. British Antarctic Survey Bulletin 76, 1–5.Google Scholar
Gordon, J.E., Harkness, D.D., 1992. Magnitude and geographic variation of the radiocarbon content in Antarctic marine life: implications for reservoir corrections in radiocarbon dating. Quaternary Science Reviews 11, 697–708.Google Scholar
Gordon, J.E., Haynes, V.M., Hubbard, A., 2008. Recent glacier changes and climate trends on South Georgia. Global and Planetary Change 60, 72–84.Google Scholar
Graham, A.G.C., Fretwell, P.T., Larter, R.D., Hodgson, D.A., Wilson, C.K., Tate, A.J., Morris, P., 2008. A new bathymetric compilation highlighting extensive paleo–ice sheet drainage on the continental shelf, South Georgia, sub-Antarctica. Geochemistry, Geophysics, Geosystems 9, 1–21.Google Scholar
Graham, A.G.C., Kuhn, G., Meisel, O., Hillenbrand, C.-D., Hodgson, D.A., Ehrmann, W., Wacker, L., et al., 2017. Major advance of South Georgia glaciers during the Antarctic Cold Reversal following extensive sub-Antarctic glaciation. Nature Communications 8, 14798.Google Scholar
Greene, S.W., 1964. The Vascular Flora of South Georgia. British Antarctic Survey, Scientific Reports 45. British Antarctic Survey, London.Google Scholar
Grobe, H., 1987. A simple method for the determination of ice-rafted debris in sediment cores. Polarforschung 57, 123–126.Google Scholar
Hall, B., 2009. Holocene glacial history of Antarctica and the sub-Antarctic islands. Quaternary Science Reviews 28, 2213–2230.Google Scholar
Hargraves, P.E., French, F.W., 1983. Diatom resting spores: significance and strategies. In: Fryxell, G. (Ed.), Survival Strategies of the Algae. Cambridge University Press, New York, pp. 49–68.Google Scholar
Hasle, G.R., Syvertsen, E.E., 1997. Marine diatoms. In: Tomas, C.R. (Ed.), Identifying Marine Phytoplankton. Academic Press, San Diego, CA, pp. 5–385.Google Scholar
Hodgson, D.A., Graham, A.G.C., Giffiths, H.J., Roberts, S.J., Ó Cofaigh, C., Bentley, M.J., Evans, D.J.A., 2014a. Glacial history of sub-Antarctic South Georgia based on the submarine geomorphology of its fjords. Quaternary Science Reviews 89, 129–147.Google Scholar
Hodgson, D.A., Graham, A.G.C., Roberts, S.J., Bentley, M.J., Ó Cofaigh, C., Verleyen, E., Vyverman, W., et al., 2014b. Terrestrial and submarine evidence for the extent and timing of the Last Glacial Maximum and the onset of deglaciation on the maritime-Antarctic and sub-Antarctic islands. Quaternary Science Reviews 100, 137–158.Google Scholar
Höfle, S., Rethemeyer, J., Mueller, C.W., John, S., 2013. Organic matter composition and stabilization in a polygonal tundra soil of the Lena Delta. Biogeosciences 10, 3145–3158.Google Scholar
Hogg, A.G., Hua, Q., Blackwell, P.G., Buck, C.E., Guilderson, T.P., Heaton, T.J., Niu, M., et al., 2013. SHCal13 Southern Hemisphere calibration, 0–50,000 years cal BP. Radiocarbon 55, 1889–1903.Google Scholar
Johansen, J.R., Fryxell, G.A., 1985. The genus Thalassiosira (Bacillariophyceae): studies on species occurring south of the Antarctic Convergence Zone. Phycologia 24, 155–179.Google Scholar
Kaplan, M.R., Schaefer, J.M., Strelin, J.A., Denton, G.H., Anderson, R.F., Vandergoes, M.J., Finkel, R.C., et al., 2016. Patagonian and southern South Atlantic view of Holocene climate. Quaternary Science Reviews 141, 112–125.Google Scholar
Krebs, W.N., 1983. Ecology of neritic marine diatoms, Arthur Harbor, Antarctica. Micropaleontology 29, 267–297.Google Scholar
Lamb, A.L., Wilson, G.P., Leng, M.J., 2006. A review of coastal palaeoclimate and relative sea-level reconstructions using δ13C and C/N ratios in organic material. Earth-Science Reviews 75, 29–57.Google Scholar
Lamy, F., Kilian, R., Arz, H.W., Francois, J.-P., Kaiser, J., Prange, M., Steinke, T., 2010. Holocene changes in the position and intensity of the southern westerly wind belt. Nature Geoscience 3, 695–699.Google Scholar
Lange, P., Tenenbaum, D., De Santis Braga, E., Campos, L., 2007. Microphytoplankton assemblages in shallow waters at Admiralty Bay (King George Island, Antarctica) during the summer 2002–2003. Polar Biology 30, 1483–1492.Google Scholar
Leng, M., Lewis, J.P., 2017. C/N ratios and carbon isotope composition of organic matter in estuarine environments. In: Weckström, K., Saunders, K., Gell, P., Skilbeck, G. (Eds.), Applications of Paleoenvironmental Techniques in Estuarine Studies. Springer, Dordrecht, the Netherlands, pp. 213–327.Google Scholar
Marzi, R., Torkelson, B.E., Olson, R.K., 1993. A revised carbon preference index. Organic Geochemistry 8, 1303–1306.Google Scholar
Melles, M., Bennicke, O., Leng, M., Ritter, B., Viehberg, F., White, D., 2013. Late Quaternary climatic and environmental history of South Georgia. In: G. Bohrmann (Ed.), The Expedition of the Research Vessel “Polarstern” to the Antarctic in 2013 (ANT-XXIX/4). Reports on Polar and Marine Research 668, 117–135.Google Scholar
Menounos, B., Clague, J.J., Osborn, G., Davis, P.T., Ponce, F., Goehring, B., Maurer, M., Rabassa, J., Coronato, A., Marr, R., 2013. Latest Pleistocene and Holocene glacier fluctuations in southernmost Tierra del Fuego, Argentina. Quaternary Science Reviews 77, 70–79.Google Scholar
Moreton, S.G., Rosqvist, G.C., Davies, S.J., Bentley, M.J., 2004. Radiocarbon reservoir ages from freshwater lakes, South Georgia, sub-Antarctic: modern analogues from particulate organic matter and surface sediments. Radiocarbon 46, 621–662.Google Scholar
Mulvaney, R., Abram, N.J., Hindmarsh, R.C.A., Arrowsmith, C., Fleet, L., Triest, J., Sime, L.C., Alemany, O., Foord, S., 2012. Recent Antarctic Peninsula warming relative to Holocene climate and ice-shelf history. Nature 489, 141–145.Google Scholar
Ó Cofaigh, C., Davies, B., Livingstone, S.J., Smith, J., Johnson, J.S., Hocking, E.P., Hodgson, D.A., et al., 2014. Reconstruction of ice-sheet changes in the Antarctic Peninsula since the Last Glacial Maximum. Quaternary Science Reviews 100, 87–110.Google Scholar
Oerlemans, J., 2005. Extracting a climate signal from 169 glacier records. Science 29, 675–677.Google Scholar
Ohkuchi, N., Eglinton, T.I., 2008. Compound-specific radiocarbon dating of Ross Sea sediments: a prospect for constructing chronologies in high-latitude oceanic sediments. Quaternary Geochronology 3, 235–243.Google Scholar
Oppedal, L.T., Bakke, J., Paasche, Ø., Werner, J.P., van der Bilt, W.G.M., 2018. Cirque glaciers on South Georgia shows centennial variability over the last 7000 years. Frontiers in Earth Science 6, 2.Google Scholar
Orsi, A.H., Witworth, T. III, Nowlin, W.D., 1995. On the meridional extent and fronts of the Antarctic Circum Polar Current. Deep-Sea Research I: Oceanographic Research Papers 42, 641–673.Google Scholar
Pancost, R., Boot, C.S., 2004. The paleoclimatic utility of terrestrial biomarkers in marine sediments. Marine Chemistry 92, 239–261.Google Scholar
Pedro, J.B., Bostock, H.C., Bitz, C.M., He, F., Vandergoes, M.J., Steig, E.J., Chase, B.M, et al., 2016. The spatial extent and dynamics of the Antarctic Cold Reversal. Nature Geoscience 9, 51–55.Google Scholar
Perren, B., Axford, Y., Kaufman, D.S., 2017. Alder, nitrogen, and lake ecology: terrestrial-aquatic linkages in the postglacial history of Lone Spruce Pond, southwestern Alaska. PLoS ONE 12, e0169106.Google Scholar
Reimer, P., Bard, E., Bayliss, A., Beck, J.W., Blackwell, P.G., Bronk Ramsey, C., Buck, C.E., et al., 2013. IntCal13 and Marine13 radiocarbon age calibration curves 0–50,000 years cal BP. Radiocarbon 55, 1869–1887.Google Scholar
Rethemeyer, J., Dewald, A., Fülöp, R., Hajdas, I., Höfle, S., Patt, U., Stapper, B., Wacker, L., 2013. Status report on sample preparation facilities for 14C analysis at the new CologneAMS centr. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 294, 168–172.Google Scholar
Roberts, S.J., Hodgson, D.A., Shelley, S., Royles, J., Griffiths, H.J., Deen, T.J., Thorne, M.A.S., 2010. Establishing lichenometric ages for nineteenth- and twentieth-century glacier fluctuations on South Georgia (South Atlantic). Geografiska Annaler 92A, 125–139.Google Scholar
Rosqvist, G.C., Rietti-Shati, M., Shemesh, A., 1999. Late glacial to middle Holocene climate record of lacustrine biogenic silica oxygen isotopes from a Southern Ocean island. Geology 27, 967–970.Google Scholar
Rosqvist, G.C., Schuber, P., 2003. Millennial-scale climate changes on South Georgia, Southern Ocean. Quaternary Research 59, 470–475.Google Scholar
Sakamoto, T., Ikehara, M., Aoki, K., Iijima, K., Kimura, N., Nakatsuka, T., Wakatsuchi, M., 2005. Ice-rafted debris (IRD)-based sea-ice expansion events during the past 100 kyrs in the Okhotsk Sea. Deep-Sea Research Part II: Topical Studies in Oceanography 52, 2275–2301.Google Scholar
Saros, J.E., Anderson, N.J., 2015. The ecology of the planktonic diatom Cyclotella and its implications for global environmental change studies. Biological Reviews 90, 522–541.Google Scholar
Scherer, R.P., 1994. A new method for the determination of absolute abundance of diatoms and other silt-sized sedimentary particles. Journal of Paleolimnology 12, 171–179.Google Scholar
Scott, F.J., Thomas, D.P., 2005. Diatoms. In: Scott, F.J., Marchant, H.J. (Eds.), Antarctic Marine Protists. Australian Biological Resources Study, Australian Antarctic Division, Canberra, pp. 13–201.Google Scholar
Sime, L.C., Kohfeld, K.E., Le Quéré, C., Wolff, E.W., de Boer, A.M., Graham, R.M., Bopp, L. 2013. Southern Hemisphere westerly wind changes during the Last Glacial Maximum: model-data comparison. Quaternary Science Reviews, 64, 104–120.Google Scholar
Simms, A.R., Ivins, E.R., DeWitt, R., Kouremenos, P., Simkins, L.M., 2012. Timing of the most recent Neoglacial advance and retreat in the South Shetland Islands, Antarctic Peninsula: insights from raised beaches and Holocene uplift rates. Quaternary Science Reviews 47, 41–55.Google Scholar
Smith, R.I., 2000. Diamictic sediments within high Arctic lake sediments cores: evidence for lake ice rafting along the lateral glacial margin. Sedimentology 47, 1157–1179.Google Scholar
Strother, S.L., Salzmann, U., Roberts, S.J., Hodgson, D.A., Woodward, J., Van Nieuvenhuyze, W., Verleyen, E., Vyverman, W., Moreton, S.G., 2015. Changes in Holocene climate and the intensity of Southern Hemisphere Westerly Winds based on a high-resolution palynological record from sub-Antarctic South Georgia. Holocene 25, 263–279.Google Scholar
Toggweiler, J.R., 2009. Shifting westerlies. Science 323, 1434–1435.Google Scholar
Trouet, V., Van Oldenborgh, G.J., 2013. KNMI Climate Explorer: a web-based research tool for high-resolution paleoclimatology. Tree-Ring Research 69, 3–13.Google Scholar
Turney, C.S.M., Jones, R.T., Fogwill, C., Hatton, J., Williams, A.N., Hogg, A., Thomas, Z.A., Palmer, J., Mooney, S., Reimer, R.W., 2016. A 250-year periodicity in the Southern Hemisphere westerly winds over the last 2600 years. Climate of the Past 12, 189–200.Google Scholar
Uchida, M., Shibata, Y., Kawamura, K., Kumamoto, Y., Yoneda, M., Ohkushi, K., Harada, N., et al., 2001. Compound-specific radiocarbon ages of fatty acids in marine sediments from the western North Pacific. Radiocarbon 43, 949–956.Google Scholar
Van der Bilt, W.G.M., Bakke, J., Werner, J.P., Paasche, Ø., Rosqvist, G., Solheim Vatle, S., 2017. Late Holocene glacier reconstructions reveals retreat behind present limits and two-stage Little Ice Age on subantarctic South Georgia. Journal of Quaternary Science 32, 888–901.Google Scholar
Van der Putten, N., Stieperaere, H., Verbruggen, C., Ochyra, R., 2004. Holocene palaeoecology and climate history of South Georgia (sub-Antarctica) based on a macrofossil record of bryophytes and seeds. Holocene 14, 382–392.Google Scholar
Van der Putten, N., Verbruggen, C., 2005. The onset of deglaciation of Cumberland Bay and Stromness Bay, South Georgia. Antarctic Science 17, 29–32.Google Scholar
Van der Putten, N., Verbruggen, C., Björck, S., de Beaulieu, J.-L., Barrow, C.J., Frenot, Y., 2012. Is palynology a credible climate proxy in the Subantarctic? Holocene 22, 1113–1121.Google Scholar
Van der Putten, N., Verbruggen, C., Ochyra, R., Spassov, S., de Beaulieu, J.-L., De Dapper, M., Hus, J., Thouveny, N., 2009. Peat bank growth, Holocene palaeoecology and climate history of South Georgia (sub-Antarctica), based on a botanical macrofossil record. Quaternary Science Reviews 28, 65–79.Google Scholar
Volkman, J.K., Johns, R.B., Gillan, F.T., Perry, G.J., Bavor, H.J. Jr., 1980. Microbial lipids of an intertidal sediment—I. Fatty acids and hydrocarbons. Geochimica et Cosmochimca Acta 44, 1133–1143.Google Scholar
Wacker, L., Bonani, G., Friedrich, M., Hajadas, I., Kromer, B., Nemec, M., Ruff, M., Suter, M., Synal, H.-A., Vockenhuber, C., 2010. MICADAS: routine and high-precision radiocarbon dating. Radiocarbon 52, 252–262.Google Scholar
White, D.A., Bennike, O., Melles, M., Berg, S., 2017. Was South Georgia covered by an ice cap during the Last Glacial Maximum? In: Siegert, M.J., Jamieson, S.S.R., White, D.A. (Eds.), Exploration of Subsurface Antarctica: Uncovering Past Changes and Modern Processes. Geological Society, London, Special Publications 461, 49–59.Google Scholar
Xiao, W., Esper, O., Gersonde, R., 2016. Last Glacial-Holocene climate variability in the Atlantic sector of the Southern Ocean. Quaternary Science Reviews 135, 115–137.Google Scholar
Supplementary material: PDF

Berg et al. supplementary material

Berg et al. supplementary material 1

Download Berg et al. supplementary material(PDF)
PDF 480.4 KB
Supplementary material: File

Berg et al. supplementary material

Berg et al. supplementary material 2

Download Berg et al. supplementary material(File)
File 43.1 KB