Articles | Volume 9, issue 3
https://doi.org/10.5194/cp-9-1015-2013
© Author(s) 2013. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
https://doi.org/10.5194/cp-9-1015-2013
© Author(s) 2013. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Large spatial variations in coastal 14C reservoir age – a case study from the Baltic Sea
B. C. Lougheed
Department of Geology, Lund University, Sölvegatan 12, 22362 Lund, Sweden
H. L. Filipsson
Department of Geology, Lund University, Sölvegatan 12, 22362 Lund, Sweden
I. Snowball
Department of Geology, Lund University, Sölvegatan 12, 22362 Lund, Sweden
Department of Earth Sciences – Geophysics, Uppsala University, Villavägen 16, 75236 Uppsala, Sweden
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Babette Hoogakker, Catherine Davis, Yi Wang, Stepanie Kusch, Katrina Nilsson-Kerr, Dalton Hardisty, Allison Jacobel, Dharma Reyes Macaya, Nicolaas Glock, Sha Ni, Julio Sepúlveda, Abby Ren, Alexandra Auderset, Anya Hess, Katrina Meissner, Jorge Cardich, Robert Anderson, Christine Barras, Chandranath Basak, Harold Bradbury, Inda Brinkmann, Alexis Castillo, Madelyn Cook, Kassandra Costa, Constance Choquel, Paula Diz, Jonas Donnenfield, Felix Elling, Zeynep Erdem, Helena Filipsson, Sebastian Garrido, Julia Gottschalk, Anjaly Govindankutty Menon, Jeroen Groeneveld, Christian Hallman, Ingrid Hendy, Rick Hennekam, Wanyi Lu, Jean Lynch-Stieglitz, Lelia Matos, Alfredo Martínez-García, Giulia Molina, Práxedes Muñoz, Simone Moretti, Jennifer Morford, Sophie Nuber, Svetlana Radionovskaya, Morgan Raven, Christopher Somes, Anja Studer, Kazuyo Tachikawa, Raúl Tapia, Martin Tetard, Tyler Vollmer, Shuzhuang Wu, Yan Zhang, Xin-Yuan Zheng, and Yuxin Zhou
EGUsphere, https://doi.org/10.5194/egusphere-2023-2981, https://doi.org/10.5194/egusphere-2023-2981, 2024
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Paleo-oxygen proxies can extend current records, bound pre-anthropogenic baselines, provide datasets necessary to test climate models under different boundary conditions, and ultimately understand how ocean oxygenation responds on longer timescales. Here we summarize current proxies used for the reconstruction of Cenozoic seawater oxygen levels. This includes an overview of the proxy's history, how it works, resources required, limitations, and future recommendations.
K. Mareike Paul, Martijn Hermans, Sami A. Jokinen, Inda Brinkmann, Helena L. Filipsson, and Tom Jilbert
Biogeosciences, 20, 5003–5028, https://doi.org/10.5194/bg-20-5003-2023, https://doi.org/10.5194/bg-20-5003-2023, 2023
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Seawater naturally contains trace metals such as Mo and U, which accumulate under low oxygen conditions on the seafloor. Previous studies have used sediment Mo and U contents as an archive of changing oxygen concentrations in coastal waters. Here we show that in fjords the use of Mo and U for this purpose may be impaired by additional processes. Our findings have implications for the reliable use of Mo and U to reconstruct oxygen changes in fjords.
Inda Brinkmann, Christine Barras, Tom Jilbert, Tomas Næraa, K. Mareike Paul, Magali Schweizer, and Helena L. Filipsson
Biogeosciences, 19, 2523–2535, https://doi.org/10.5194/bg-19-2523-2022, https://doi.org/10.5194/bg-19-2523-2022, 2022
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The concentration of the trace metal barium (Ba) in coastal seawater is a function of continental input, such as riverine discharge. Our geochemical records of the severely hot and dry year 2018, and following wet year 2019, reveal that prolonged drought imprints with exceptionally low Ba concentrations in benthic foraminiferal calcium carbonates of coastal sediments. This highlights the potential of benthic Ba / Ca to trace past climate extremes and variability in coastal marine records.
Constance Choquel, Emmanuelle Geslin, Edouard Metzger, Helena L. Filipsson, Nils Risgaard-Petersen, Patrick Launeau, Manuel Giraud, Thierry Jauffrais, Bruno Jesus, and Aurélia Mouret
Biogeosciences, 18, 327–341, https://doi.org/10.5194/bg-18-327-2021, https://doi.org/10.5194/bg-18-327-2021, 2021
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Marine microorganisms such as foraminifera are able to live temporarily without oxygen in sediments. In a Swedish fjord subjected to seasonal oxygen scarcity, a change in fauna linked to the decrease in oxygen and the increase in an invasive species was shown. The invasive species respire nitrate until 100 % of the nitrate porewater in the sediment and could be a major contributor to nitrogen balance in oxic coastal ecosystems. But prolonged hypoxia creates unfavorable conditions to survive.
Laurie M. Charrieau, Karl Ljung, Frederik Schenk, Ute Daewel, Emma Kritzberg, and Helena L. Filipsson
Biogeosciences, 16, 3835–3852, https://doi.org/10.5194/bg-16-3835-2019, https://doi.org/10.5194/bg-16-3835-2019, 2019
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We reconstructed environmental changes in the Öresund during the last 200 years, using foraminifera (microfossils), sediment, and climate data. Five zones were identified, reflecting oxygen, salinity, food content, and pollution levels for each period. The largest changes occurred ~ 1950, towards stronger currents. The foraminifera responded quickly (< 10 years) to the changes. Moreover, they did not rebound when the system returned to the previous pattern, but displayed a new equilibrium state.
Jeroen Groeneveld, Helena L. Filipsson, William E. N. Austin, Kate Darling, David McCarthy, Nadine B. Quintana Krupinski, Clare Bird, and Magali Schweizer
J. Micropalaeontol., 37, 403–429, https://doi.org/10.5194/jm-37-403-2018, https://doi.org/10.5194/jm-37-403-2018, 2018
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Current climate and environmental changes strongly affect shallow marine and coastal areas like the Baltic Sea. The combination of foraminiferal geochemistry and environmental parameters demonstrates that in a highly variable setting like the Baltic Sea, it is possible to separate different environmental impacts on the foraminiferal assemblages and therefore use chemical factors to reconstruct how seawater temperature, salinity, and oxygen varied in the past and may vary in the future.
Irina Polovodova Asteman, Helena L. Filipsson, and Kjell Nordberg
Clim. Past, 14, 1097–1118, https://doi.org/10.5194/cp-14-1097-2018, https://doi.org/10.5194/cp-14-1097-2018, 2018
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We present 2500 years of winter temperatures, using a sediment record from Gullmar Fjord analyzed for stable oxygen isotopes in benthic foraminifera. Reconstructed temperatures are within the annual temperature variability recorded in the fjord since the 1890s. Results show the warm Roman and Medieval periods and the cold Little Ice Age. The record also shows the recent warming, which does not stand out in the 2500-year perspective and is comparable to the Roman and Medieval climate anomalies.
Laurie M. Charrieau, Lene Bryngemark, Ingemar Hansson, and Helena L. Filipsson
J. Micropalaeontol., 37, 191–194, https://doi.org/10.5194/jm-37-191-2018, https://doi.org/10.5194/jm-37-191-2018, 2018
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Splitting samples into smaller subsamples is often necessary in micropalaeontological studies. Indeed, the general high abundance of microfossils – which makes them excellent tools to reconstruct past environments – also results in very time-consuming faunal analyses. Here we present an improved and cost-effective wet splitter for micropalaeontological samples aimed to reduce picking time, while keeping information loss to a minimum.
Ulrich Kotthoff, Jeroen Groeneveld, Jeanine L. Ash, Anne-Sophie Fanget, Nadine Quintana Krupinski, Odile Peyron, Anna Stepanova, Jonathan Warnock, Niels A. G. M. Van Helmond, Benjamin H. Passey, Ole Rønø Clausen, Ole Bennike, Elinor Andrén, Wojciech Granoszewski, Thomas Andrén, Helena L. Filipsson, Marit-Solveig Seidenkrantz, Caroline P. Slomp, and Thorsten Bauersachs
Biogeosciences, 14, 5607–5632, https://doi.org/10.5194/bg-14-5607-2017, https://doi.org/10.5194/bg-14-5607-2017, 2017
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We present reconstructions of paleotemperature, paleosalinity, and paleoecology from the Little Belt (Site M0059) over the past ~ 8000 years and evaluate the applicability of numerous proxies. Conditions were lacustrine until ~ 7400 cal yr BP. A transition to brackish–marine conditions then occurred within ~ 200 years. Salinity proxies rarely allowed quantitative estimates but revealed congruent results, while quantitative temperature reconstructions differed depending on the proxies used.
Wenxin Ning, Jing Tang, and Helena L. Filipsson
Earth Surf. Dynam., 4, 773–780, https://doi.org/10.5194/esurf-4-773-2016, https://doi.org/10.5194/esurf-4-773-2016, 2016
J. M. Bernhard, W. G. Phalen, A. McIntyre-Wressnig, F. Mezzo, J. C. Wit, M. Jeglinski, and H. L. Filipsson
Biogeosciences, 12, 5515–5522, https://doi.org/10.5194/bg-12-5515-2015, https://doi.org/10.5194/bg-12-5515-2015, 2015
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We present an innovative method using osmotic pumps and the fluorescent marker calcein to help identify where and when calcareous bottom-dwelling organisms mineralize in sediments. These organisms, and their geochemical signatures in their carbonate, are the ocean’s storytellers helping us understand past marine conditions. For many species, the timing and location of their calcite growth is not known. Knowing this will enable us to reconstruct past marine environments with greater accuracy.
C. L. McKay, J. Groeneveld, H. L. Filipsson, D. Gallego-Torres, M. J. Whitehouse, T. Toyofuku, and O.E. Romero
Biogeosciences, 12, 5415–5428, https://doi.org/10.5194/bg-12-5415-2015, https://doi.org/10.5194/bg-12-5415-2015, 2015
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We highlight the proxy potential of foraminiferal Mn/Ca determined by secondary ion mass spectrometry and flow-through inductively coupled plasma optical emission spectroscopy for recording changes in bottom-water oxygen conditions. Comparisons with Mn sediment bulk measurements from the same sediment core largely agree with the results. High foraminiferal Mn/Ca occurs in samples from times of high productivity export and corresponds with the benthic foraminiferal faunal composition.
M. P. Nardelli, C. Barras, E. Metzger, A. Mouret, H. L. Filipsson, F. Jorissen, and E. Geslin
Biogeosciences, 11, 4029–4038, https://doi.org/10.5194/bg-11-4029-2014, https://doi.org/10.5194/bg-11-4029-2014, 2014
J. Groeneveld and H. L. Filipsson
Biogeosciences, 10, 5125–5138, https://doi.org/10.5194/bg-10-5125-2013, https://doi.org/10.5194/bg-10-5125-2013, 2013
I. Polovodova Asteman, K. Nordberg, and H. L. Filipsson
Biogeosciences, 10, 1275–1290, https://doi.org/10.5194/bg-10-1275-2013, https://doi.org/10.5194/bg-10-1275-2013, 2013
Related subject area
Subject: Proxy Use-Development-Validation | Archive: Marine Archives | Timescale: Instrumental Period
Variability in Neogloboquadrina pachyderma stable isotope ratios from isothermal conditions: implications for individual foraminifera analysis
Sea ice dynamics in the Bransfield Strait, Antarctic Peninsula, during the past 240 years: a multi-proxy intercomparison study
A proxy modelling approach to assess the potential of extracting ENSO signal from tropical Pacific planktonic foraminifera
Lukas Jonkers, Geert-Jan A. Brummer, Julie Meilland, Jeroen Groeneveld, and Michal Kucera
Clim. Past, 18, 89–101, https://doi.org/10.5194/cp-18-89-2022, https://doi.org/10.5194/cp-18-89-2022, 2022
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The variability in the geochemistry among individual foraminifera is used to reconstruct seasonal to interannual climate variability. This method requires that each foraminifera shell accurately records environmental conditions, which we test here using a sediment trap time series. Even in the absence of environmental variability, planktonic foraminifera display variability in their stable isotope ratios that needs to be considered in the interpretation of individual foraminifera data.
Maria-Elena Vorrath, Juliane Müller, Lorena Rebolledo, Paola Cárdenas, Xiaoxu Shi, Oliver Esper, Thomas Opel, Walter Geibert, Práxedes Muñoz, Christian Haas, Gerhard Kuhn, Carina B. Lange, Gerrit Lohmann, and Gesine Mollenhauer
Clim. Past, 16, 2459–2483, https://doi.org/10.5194/cp-16-2459-2020, https://doi.org/10.5194/cp-16-2459-2020, 2020
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We tested the applicability of the organic biomarker IPSO25 for sea ice reconstructions in the industrial era at the western Antarctic Peninsula. We successfully evaluated our data with satellite sea ice observations. The comparison with marine and ice core records revealed that sea ice interpretations must consider climatic and sea ice dynamics. Sea ice biomarker production is mainly influenced by the Southern Annular Mode, while the El Niño–Southern Oscillation seems to have a minor impact.
Brett Metcalfe, Bryan C. Lougheed, Claire Waelbroeck, and Didier M. Roche
Clim. Past, 16, 885–910, https://doi.org/10.5194/cp-16-885-2020, https://doi.org/10.5194/cp-16-885-2020, 2020
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Planktonic foraminifera construct a shell that, post mortem, settles to the seafloor, prior to collection by Palaeoclimatologists for use as proxies. Such organisms in life are sensitive to the ambient conditions (e.g. temperature, salinity), which therefore means our proxies maybe skewed toward the ecology of organisms. Using a proxy system model, Foraminifera as Modelled Entities (FAME), we assess the potential of extracting ENSO signal from tropical Pacific planktonic foraminifera.
Cited articles
Adolphi, F.: Holocene temperature reconstruction in Baltic Sea sediments for the last 2000 years, using the biomarker TEX86, MSc Theis, 94 pp., Technical University Bergakademie, Freiburg, 2010.
Andersson, P. S., Wasserburg, G. J., and Ingri, J.: The sources and transport of Sr and Nd isotopes in the Baltic Sea, Earth Planet. Sc. Lett., 113, 459–472, 1992.
Ascough, P., Cook, G., and Dugmore, A.: Methodological approaches to determining the marine radiocarbon reservoir effect, Progr. Phys. Geogr., 29, 532–547, 2005a.
Ascough, P. L., Cook, G. T., Dugmore, A. J., Scott, E. M., and Freeman, S. P. H. T.: Influence of mollusc species on marine $\Delta R$ determinations, Radiocarbon, 47, 433–440, 2005b.
Austin, W. E. N., Cage, A. G., and Scourse, J. D.: Mid-latitude shelf seas: a NW European perspective on the seasonal dynamics of temperature, salinity and oxygen isotopes, Holocene, 16, 937–947, 2006.
Austin, W. E. N., Telford, R. J., Ninnemann, U. S., Brown, L., Wilson, L. J., Small, D. P., and Bryant, C. L.: North Atlantic reservoir ages linked to high Younger Dryas atmospheric radiocarbon concentrations, Global Planet. Change, 79, 226–233, 2011.
Berglund, B: The Post-Glacial Shore Displacement in Eastern Blekinge, Southeastern Sweden, in: Publications from the Institutes of Mineralogy, Paleontology and Quaternary Geology, University of Lund, Sweden, Sveriges Geologiska Undersökning (SGU), Stockholm, Ser C, Nr. 599, 1964.
BGR Hannover, EGS Brussels, UNESCO: International Hydrogeological Map of Europe (1 : 5,000,000), UNESCO Publishing, Paris, 2008.
Björck, S.: A review of the history of the Baltic Sea, 13.0–8.0 ka BP, Quaternary Int., 27, 19–40, 1995.
Bondevik, S., Birks, H. H., Gulliksen, S., and Mangerud, J.: Late Weichselian Marine 14C Reservoir Ages at the Western Coast of Norway, Quaternary Res., 52, 104–114, 1999.
Bondevik, S., Mangerud, J., Birks, H. H., Gulliksen, S., and Reimer, P.: Changes in North Atlantic Radiocarbon Reservoir Ages During the Allerød and Younger Dryas, Science, 312, 1514–1517, 2006.
Budd, G. and Rayment, W.: Macoma balthica. Baltic tellin, Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme, available at: http://www.marlin.ac.uk/ (last access: 18 April 2013), Plymouth: Marine Biological Association of the United Kingdom, 2001.
Cage, A. G., Heinemeier, J., and Austin, W. E. N.: Marine radiocarbon reservoir ages in scottish coastal and fjordic waters, Radiocarbon, 48, 31–43, 2006.
Carstensen, J., Conley, D. J., Lophaven, S., Danielsson, Å., Rahm, L., and Toompuu, A.: Statistical Analysis and Modelling of Phytoplankton Dynamics: Exploitation of Data in the Nordic and Baltic Monitoring Programs, Nordic Council of Ministers, 2002.
Damon, P. E., Lerman, J. C., and Long, A.: Temporal fluctuations of atmospheric 14C: causal factors and implications, Annual Rev. Earth Planet. Sc., 6, 457–494, 1978.
Ehhalt, D. H.: On the deuterium-salinity relationship in the Baltic Sea, Tellus, 21, 429–435, 1969.
Emeis, K.-C., Struck, U., Blanz, T., Kohly, A., and Vo{ß}, M.: Salinity changes in the central Baltic Sea (NW Europe) over the last 10 000 years, Holocene, 13, 411–421, 2003.
Engstrand, L. G.: Stockholm natural radiocarbon measurements VI, Radiocarbon, 7, 257–290, 1965.
Fröhlich, K., Grabczak, J., and Rozanski, K.: Deuterium and oxygen-18 in the baltic sea, Chem. Geol., 72, 77–83, 1988.
Gordon, J. E. and Harkness, D. D.: Magnitude and geographic variation of the radiocarbon content in Antarctic marine life: Implications for reservoir corrections in radiocarbon dating, Quaternary Sci. Rev., 11, 697–708, 1992.
Grossman, E. L. and Ku, T. L.: Oxygen and carbon isotope fractionation in biogenic aragonite: temperature effects, Chem. Geol., 59, 59–74, 1986.
Gustafsson, B. G. and Westman, P.: On the causes for salinity variations in the Baltic Sea during the last 8500 years, Paleoceanography, 17, 12.1–12.14, https://doi.org/10.1029/2000PA000572, 2002.
Heier-Nielsen, S., Heinemeier, J., Nielsen, H. L., and Rud, N.: Recent reservoir ages for Danish fjords and marine waters., Radiocarbon, 37, 875–882, 1995.
HELCOM: Approaches and methods for eutrophication target setting in the Baltic Sea region, Balt. Sea Environ. Proc., No. 133, 2013.
Hut, G.: Consultants' group meeting on stable isotope reference samples for geochemical and hydrological investigations, Report to the Director General, International Atomic Energy Agency, Vienna, April, 1987.
IOC, IHO, BODC: Centenary Edition of the GEBCO Digital Atlas. British Oceanographic Data Centre, Liverpool, 2003.
Janssen, F., Schrum, C., and Backhaus, J. O.: A climatological data set of temperature and salinity for the Baltic Sea and the North Sea, Deutsche Hydrographische Zeitschrift, 51, 5–245, 1999.
Kalberg, T., Suuroja, A., Põldvere, A., and Hints, O.: Bedrock Geological Map of Estonia, Geological Survey of Estonia and Geological Society of Estonia, 2007.
Kotilainen, A. T., Saarinen, T., and Winterhalter, B.: High-resolution paleomagnetic dating of sediments deposited in the central Baltic Sea during the last 3000 years, Mar. Geol., 166, 51–64, 2000.
Lougheed, B. C., Snowball, I., Moros, M., Kabel, K., Muscheler, R., Virtasalo, J. J., and Wacker, L.: Using an independent geochronology based on palaeomagnetic secular variation (PSV) and atmospheric Pb deposition to date Baltic Sea sediments and infer 14C reservoir age, Quaternary Sci. Rev., 42, 43–58, 2012.
Mangerud, J., Bondevik, S., Gulliksen, S., Karin Hufthammer, A., and Høisæter, T.: Marine 14C reservoir ages for 19th century whales and molluscs from the North Atlantic, Quaternary Sc. Rev., 25, 3228–3245, 2006.
Matthäus, W. and Schinke, H.: The influence of river runoff on deep water conditions of the Baltic Sea, Hydrobiologia, 393, 1–10, 1999.
Meyer, M. and Harff, J.: Modelling Palaeo Coastline Changes of the Baltic Sea, J. Coast. Res., 213, 598–609, 2005.
Olsen, J., Rasmussen, P., and Heinemeier, J.: Holocene temporal and spatial variation in the radiocarbon reservoir age of three Danish fjords, Boreas, 38, 458–470, 2009.
Olsson, I.: A warning against radiocarbon dating of samples containing little carbon, Boreas, 8, 203–207, 1979.
Olsson, I.: Content of C-14 in marine mammals from northern Europe, Radiocarbon, 22, 662–675, 1980.
Paukstys, B. and Narbutas, V.: Gypsum Karst of the Baltic Republics, Gypsum karst of the World, Int. J. Speleol., 25, 279–284, 1996.
Philipssen, B. and Heinemeier, J.: Freshwater reservoir effect variability in Northern Germany, Radiocarbon, in press, 2013.
Punning, J.-M., Vaikmäe, R., and Mäekivi, S.: Oxygen-18 variations in the Baltic Sea, The International journal of radiation applications and instrumentation, Nucl. Geophys., 5, 529–539, 1991.
Reimer, P. J., Baillie, M. G. L., Bard, E., Bayliss, A., Beck, J. W., Bertrand, C. J. H., Blackwell, P. G., Buck, C. E., Burr, G. S., Cutler, K. B., Damon, P. E., Edwards, R. L., Fairbanks, R. G., Friedrich, M., Guilderson, T. P., Hogg, A. G., Hughen, K. A., Kromer, B., McCormac, G., Manning, S., Ramsey, C. B., Reimer, R. W., Remmele, S., Southon, J. R., Stuiver, M., Talamo, S., Taylor, F. W., van der Plicht, J., and Weyhenmeyer, C. E.: IntCal04 terrestrial radiocarbon age calibration, 0–26 cal kyr BP, Radiocarbon, 46, 1029–1058, 2004.
Reimer, P. J., Baillie, M. G. L., Bard, E., Bayliss, A., Beck, J. W., Blackwell, P. G., Ramsey, C. B., Buck, C. E., Burr, G. S., Edwards, R. L., Friedrich, M., Grootes, P. M., Guilderson, T. P., Hajdas, I., Heaton, T. J., Hogg, A. G., Hughen, K. A., Kaiser, K. F., Kromer, B., McCormac, F. G., Manning, S. W., Reimer, R. W., Richards, D. A., Southon, J. R., Talamo, S., Turney, C. S. M., van der Plicht, J., and Weyhenmeyer, C. E.: IntCal09 and Marine09 Radiocarbon Age Calibration Curves, 0–50,000 Years cal BP, Radiocarbon, 51, 1111–1150, 2009.
Reinholdsson, M., Snowball, I., Zillén, L., Lenz, C., and Conley, D. J.: Magnetic enhancement of Baltic Sea sapropels by greigite magnetofossils, Earth Planet. Sc. Lett., 366, 137–150, 2013.
Rö{ß}ler, D., Moros, M., and Lemke, W.: The Littorina transgression in the southwestern Baltic Sea: new insights based on proxy methods and radiocarbon dating of sediment cores, Boreas, 40, 231–241, 2011.
Ruff, M., Szidat, S., Gäggeler, H. W., Suter, M., Synal, H.-A., and Wacker, L.: Gaseous radiocarbon measurements of small samples, Nucl. Instrum. Methods B, 268, 790–794, 2010.
Siegenthaler, U. and Oeschger, H.: Prediction of future CO2 concentrations in the atmosphere, Cell. Mol. Life Sci., 36, 783–786, 1980.
Siegenthaler, U., Heimann, M., and Oeschger, H.: 14C Variations Caused by Changes in the Global Carbon Cycle, Radiocarbon, 22, 177–191, 1980.
Sohlenius, G., Sternbeck, J., Andrén, E., and Westman, P.: Holocene history of the Baltic Sea as recorded in a sediment core from the Gotland Deep, Mar. Geol., 134, 183–201, 1996.
Stephens, M. B., Wahlgren, C.-H., and Weihed, P.: Tektoniska enheter in den svenska berggrunden, Swedish Geological Survey (SGU), Uppsala, 1994.
Stuiver, M., Reimer, P. J., Bard, E., Beck, J. W., Burr, G. S., Hughen, K. A., Kromer, B., McCormac, G., van der Plicht, J., and Spurk, M.: INTCAL98 radiocarbon age calibration, 24,000–0 cal BP, Radiocarbon, 40, 1041–1083, 1998.
Tanaka, N., Monaghan, M. C., and Rye, D. M.: Contribution of metabolic carbon to mollusc and barnacle shell carbonate, Nature, 320, 520–523, 1986.
Wacker, L., Lippold, J., Molnár, M. and Schulz, H.: Towards radiocarbon dating of single foraminifera with a gas ion source, Nucl. Instrum. Meth. B, 294, 307–310, 2013.
Widerlund, A. and Andersson, P. S.: Late Holocene freshening of the Baltic Sea derived from high-resolution strontium isotope analyses of mollusk shells, Geology, 39, 187–190, 2011.
Willumsen, P. S., Filipsson, H. L., Reinholdsson, M., and Lenz, C.: Surface salinity and nutrient variations during the Littorina Stage in the Fårö Deep, Baltic Sea, Boreas, 42, 210–223, 2013.
Zillén, L., Conley, D. J., Andrén, T., Andrén, E., and Björck, S.: Past occurrences of hypoxia in the Baltic Sea and the role of climate variability, environmental change and human impact, Earth-Sci. Rev., 91, 77–92, 2008.