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Title [sv]
Senpleistocen och Holocen klimatpåverkan på Östersjön
Title [en]
Late Pleistocene and Holocene climate forcing on the Baltic Sea
Abstract [en]
During autumn 2013 the first ever scientific drilling expedition in the Baltic Sea was carried out within the International Ocean Discovery Program IODP Expedition 347, Baltic Sea Paleoenvironment. The overarching objective of Expedition 347 was to gain a deeper understanding of the paleoenvironmental evolution of the Baltic Sea Basin through the last glacial cycle. After the expedition, the following Onshore Science Party in early spring 2014 carried out visual inspection and description of the cores retrieved, measurements of physical properties, and intense sampling of the cores. Initial biostratigraphic and lithologic analyses provided a preliminary chronology that, together with the visual appearance of the sediment, was used as a guide for further sampling.In general, the expedition was very successful and all of the research themes formulated in the original proposal will be explored and the objectives met. The project presented here is designed as two integrated sub-projects with the following overarching aims: • To better constrain the model of the Scandinavian Ice Sheet with its global and regional isostatic and eustatic impacts. • To investigate how Baltic in- and outflows have varied over time and how these variation are related to changes in large-scale atmospheric circulation and changing sea levels (threshold depths). • To determine the main mechanisms behind hypoxia-driving processes in the Baltic and to what degree human activities have played a role. Expected outcome It is envisaged that answering these research questions it will allow us to gain totally new scientific insights in a variety of research fields such as e.g. • regional and global issues on the timing and forcing of rapid climate change and sea levels • glacial history of the Scandinavian ice sheet and its inter-action with the climate system • mechanisms behind hypoxia-driving processes in intra-continental type of sea basins The Off- and Onshore Science Party consist of 30 specialist scientists from Europe, USA, Japan, China, Australia and New Zeeland and were selected in a strong international competition. In addition to the Co-chief Scientist Thomas Andrén another two Swedes were selected of which the siliceous microfossil specialist Elinor Andrén is also from Södertörn University. Hence Södertörn University scientists play a leading role in the Science Party.
Publications (6 of 6) Show all publications
Stepanova, A., Obrochta, S., Quintana Krupinski, N. B., Hyttinen, O., Kotilainen, A. & Andrén, T. (2019). Late Weichselian to Holocene history of the Baltic Sea as reflected in ostracod assemblages. Boreas, 48(3), 761-778
Open this publication in new window or tab >>Late Weichselian to Holocene history of the Baltic Sea as reflected in ostracod assemblages
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2019 (English)In: Boreas, ISSN 0300-9483, E-ISSN 1502-3885, Vol. 48, no 3, p. 761-778Article in journal (Refereed) Published
Abstract [en]

The study presents the first description and analysis of ostracod records from three sites cored in different parts of the Baltic Sea during the IODP Expedition 347, Baltic Sea Paleoenvironment. Our data present the first high-resolution ostracod records from the Late Weichselian and Holocene sediments collected across the Baltic Sea Basin. Using published data on modern ostracod species ecology of the Baltic Sea, we were able to provide ostracod-based palaeoreconstructions of the history of the region. The stratigraphical framework for the sites is based on radiocarbon-based age models. The three studied sites reveal different ostracod assemblage successions that reflect environmental changes in the study area. Site M0060, located in the Kattegat area, contains the oldest ostracod assemblages that document a marine environment with very high sedimentation rates during the most recent deglaciation. Between ~13 000 and 7500 cal. a BP a modern-like near-shore environment developed. Site M0059 in the southwestern Baltic Sea, Little Belt area, contains assemblages reflecting the transition from a freshwater lake to the brackish Littorina Sea between ~7500 and 7300 cal. a BP. Site M0063 is the deepest location in the central Baltic, Landsort Deep, and yielded very limited ostracod data, but comparison with our organic carbon data allowed us to distinguish the Yoldia Sea, Ancylus Lake and Littorina Sea intervals. The ostracod record correlates well with the organic carbon record with alternation between periods of hypoxia and periods of low oxygen that still supported ostracods.

Place, publisher, year, edition, pages
John Wiley & Sons, 2019
National Category
Geology
Research subject
Baltic and East European studies
Identifiers
urn:nbn:se:sh:diva-37621 (URN)10.1111/bor.12375 (DOI)2-s2.0-85060756108 (Scopus ID)2207/3.1.1/2014 (Local ID)2207/3.1.1/2014 (Archive number)2207/3.1.1/2014 (OAI)
Funder
The Foundation for Baltic and East European Studies, 2207/3.1.1/2014
Available from: 2019-02-08 Created: 2019-02-08 Last updated: 2019-08-19Bibliographically approved
van Wirdum, F., Andrén, E., Wienholz, D., Kotthoff, U., Moros, M., Fanget, A.-S. -., . . . Andrén, T. (2019). Middle to late holocene variations in salinity and primary productivity in the central Baltic Sea: A multiproxy study from the landsort deep. Frontiers in Marine Science, 6, Article ID 51.
Open this publication in new window or tab >>Middle to late holocene variations in salinity and primary productivity in the central Baltic Sea: A multiproxy study from the landsort deep
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2019 (English)In: Frontiers in Marine Science, E-ISSN 2296-7745, Vol. 6, article id 51Article in journal (Refereed) Published
Abstract [en]

Anthropogenic forcing has led to an increased extent of hypoxic bottom areas in the Baltic Sea during recent decades. The Baltic Sea ecosystem is naturally prone to the development of hypoxic conditions due to its geographical, hydrographical, geological, and climate features. Besides the current spreading of hypoxia, the Baltic Sea has experienced two extensive periods of hypoxic conditions during the Holocene, caused by changing climate conditions during the Holocene Thermal Maximum (HTM; 8–4.8 cal ka BP) and the Medieval Climate Anomaly (MCA; 1–0.7 cal ka BP). We studied the variations in surface and bottom water salinity and primary productivity and their relative importance for the development and termination of hypoxia by using microfossil and geochemical data from a sediment core retrieved from the Landsort Deep during IODP Expedition 347 (Site M0063). Our findings demonstrate that increased salinity was of major importance for the development of hypoxic conditions during the HTM. In contrast, we could not clearly relate the termination of this hypoxic period to salinity changes. The reconstructed high primary productivity associated with the hypoxic period during the MCA is not accompanied by considerable increases in salinity. Our proxies for salinity show a decreasing trend before, during and after the MCA. Therefore, we suggest that this period of hypoxia is primarily driven by increasing temperatures due to the warmer climate. These results highlight the importance of natural climate driven changes in salinity and primary productivity for the development of hypoxia during a warming climate.

Place, publisher, year, edition, pages
Frontiers Media S.A., 2019
Keywords
paleoceanography, hypoxia, geochemistry, diatoms, foraminifera, palynomorphs, IODP Expedition 347
National Category
Climate Research
Research subject
Baltic and East European studies; Environmental Studies
Identifiers
urn:nbn:se:sh:diva-37781 (URN)10.3389/fmars.2019.00051 (DOI)2-s2.0-85061721558 (Scopus ID)1562/3.1.1/2013 (Local ID)1562/3.1.1/2013 (Archive number)1562/3.1.1/2013 (OAI)
Funder
The Foundation for Baltic and East European Studies, 1562/3.1.1/2013The Foundation for Baltic and East European Studies, 2207/3.1.1/2014Swedish Research Council, 826- 2012-5114
Note

This research was supported by the Foundation for Baltic and East European Studies (Grants 1562/3.1.1/2013 and 2207/3.1.1/2014), the Swedish Research Council (Grant 826- 2012-5114), the Carlsberg Foundation (IVAR-347 project) and Geocenter Denmark (DAN-IODP-SEIS project), the Independent Research Fund Denmark (Grant 7014-00113B, G-Ice), and the German Research Foundation (DFG, projects Ko3944/6-1 and Ko3944/8–1).

Available from: 2019-03-01 Created: 2019-03-01 Last updated: 2019-06-25Bibliographically approved
Warnock, J., Bauersachs, T., Kotthoff, U., Brandt, H.-T. & Andrén, E. (2018). Holocene environmental history of the Ångermanälven Estuary, northern Baltic Sea. Boreas, 47(2), 593-608
Open this publication in new window or tab >>Holocene environmental history of the Ångermanälven Estuary, northern Baltic Sea
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2018 (English)In: Boreas, ISSN 0300-9483, E-ISSN 1502-3885, Vol. 47, no 2, p. 593-608Article in journal (Refereed) Published
Abstract [en]

The Baltic Sea has experienced a complex geological history, with notable swings in salinity driven by changes to its connection with the Atlantic and glacio-isostatic rebound. Sediments obtained during International Ocean Drilling Program Expedition 347 allow the study of the effects of these changes on the ecology of the Baltic in high resolution through the Holocene in areas where continuous records had not always been available. Sites M0061 and M0062, drilled in the Ångermanälven Estuary (northern Baltic Sea), contain records of Holocene-aged sediments and microfossils. Here we present detailed records of palaeoecological and palaeoenvironmental changes to the Ångermanälven Estuary inferred from diatom, palynomorph and organic-geochemical data. Based on diatom assemblages, the record is divided into four zones that comprise the Ancylus Lake, Littorina Sea, Post-Littorina Sea and Recent Baltic Sea stages. The Ancylus Lake phase is initially characterized as oligotrophic, with the majority of primary productivity in the upper water column. This transition to a eutrophic state continues into the Initial Littorina Sea stage. The Initial Littorina Sea stage contains the most marine phase recorded here, as well as low surface water temperatures. These conditions end before the Littorina Sea stage, which is marked by a return to oligotrophic conditions and warmer waters of the Holocene Thermal Maximum. Glacio-isostatic rebound leads to a shallowing of the water column, allowing for increased benthic primary productivity and stratification of the water column. The Medieval Climate Anomaly is also identified within Post-Littorina Sea sediments. Modern Baltic sediments and evidence of human-induced eutrophication are seen. Human influence upon the Baltic Sea begins c. 1700 cal. a BP and becomes more intense c. 215 cal. a BP.

 

National Category
Earth and Related Environmental Sciences
Research subject
Environmental Studies; Baltic and East European studies
Identifiers
urn:nbn:se:sh:diva-33375 (URN)10.1111/bor.12281 (DOI)000428369500015 ()2-s2.0-85029216223 (Scopus ID)2207/3.1.1/2014 (Local ID)2207/3.1.1/2014 (Archive number)2207/3.1.1/2014 (OAI)
Funder
The Foundation for Baltic and East European StudiesGerman Research Foundation (DFG), KO 3944/6-1German Research Foundation (DFG), BA 3841/5-1
Note

Also funded by IODP PEA.

Available from: 2017-09-13 Created: 2017-09-13 Last updated: 2019-08-19Bibliographically approved
Kotthoff, U., Groeneveld, J., Ash, J., Fanget, A.-S., Krupinski, N., Peyron, O., . . . Bauersachs, T. (2017). Reconstructing Holocene temperature and salinity variations in the western Baltic Sea region: a multi-proxy comparison from the Little Belt (IODP Expedition 347, Site M0059). Biogeosciences, 14, 5607-5632
Open this publication in new window or tab >>Reconstructing Holocene temperature and salinity variations in the western Baltic Sea region: a multi-proxy comparison from the Little Belt (IODP Expedition 347, Site M0059)
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2017 (English)In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 14, p. 5607-5632Article in journal (Refereed) Published
Abstract [en]

Sediment records recovered from the Baltic Sea during Integrated Ocean Drilling Program Expedition 347 provide a unique opportunity to study paleoenvironmental and climate change in central and northern Europe. Such studies contribute to a better understanding of how environmental parameters change in continental shelf seas and enclosed basins. Here we present a multi-proxy-based reconstruction of paleotemperature (both marine and terrestrial), paleosalinity, and paleoecosystem changes from the Little Belt (Site M0059) over the past  ∼  8000 years and evaluate the applicability of inorganic- and organic-based proxies in this particular setting. All salinity proxies (diatoms, aquatic palynomorphs, ostracods, diol index) show that lacustrine conditions occurred in the Little Belt until  ∼  7400 cal yr BP. A connection to the Kattegat at this time can thus be excluded, but a direct connection to the Baltic Proper may have existed. The transition to the brackish–marine conditions of the Littorina Sea stage (more saline and warmer) occurred within  ∼  200 years when the connection to the Kattegat became established after  ∼  7400 cal yr BP. The different salinity proxies used here generally show similar trends in relative changes in salinity, but often do not allow quantitative estimates of salinity. The reconstruction of water temperatures is associated with particularly large uncertainties and variations in absolute values by up to 8 °C for bottom waters and up to 16 °C for surface waters. Concerning the reconstruction of temperature using foraminiferal Mg  /  Ca ratios, contamination by authigenic coatings in the deeper intervals may have led to an overestimation of temperatures. Differences in results based on the lipid paleothermometers (long chain diol index and TEXL86) can partly be explained by the application of modern-day proxy calibrations to intervals that experienced significant changes in depositional settings: in the case of our study, the change from freshwater to marine conditions. Our study shows that particular caution has to be taken when applying and interpreting proxies in coastal environments and marginal seas, where water mass conditions can experience more rapid and larger changes than in open ocean settings. Approaches using a multitude of independent proxies may thus allow a more robust paleoenvironmental assessment.

National Category
Geosciences, Multidisciplinary
Research subject
Environmental Studies
Identifiers
urn:nbn:se:sh:diva-33885 (URN)10.5194/bg-14-5607-2017 (DOI)000417849900001 ()2-s2.0-85038405810 (Scopus ID)2207/3.1.1/2014 (Local ID)2207/3.1.1/2014 (Archive number)2207/3.1.1/2014 (OAI)
Funder
The Foundation for Baltic and East European Studies, 1562/3.1.1/2013The Foundation for Baltic and East European Studies, 2207/3.1.1/2014
Available from: 2017-12-14 Created: 2017-12-14 Last updated: 2019-08-19Bibliographically approved
Obrochta, S. P., Andrén, T., Fazekas, S. Z., Lougheed, B. C., Snowball, I., Yokoyama, Y., . . . Fehr, A. (2017). The undatables: Quantifying uncertainty in a highly expanded Late Glacial-Holocene sediment sequence recovered from the deepest Baltic Sea basin—IODP Site M0063. Geochemistry Geophysics Geosystems, 18(3), 858-871
Open this publication in new window or tab >>The undatables: Quantifying uncertainty in a highly expanded Late Glacial-Holocene sediment sequence recovered from the deepest Baltic Sea basin—IODP Site M0063
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2017 (English)In: Geochemistry Geophysics Geosystems, ISSN 1525-2027, E-ISSN 1525-2027, Vol. 18, no 3, p. 858-871Article in journal (Refereed) Published
Abstract [en]

Laminated, organic-rich silts and clays with high dissolved gas content characterize sediments at IODP Site M0063 in the Landsort Deep, which at 459 m is the deepest basin in the Baltic Sea. Cores recovered from Hole M0063A experienced significant expansion as gas was released during the recovery process, resulting in high sediment loss. Therefore, during operations at subsequent holes, penetration was reduced to 2 m per 3.3 m core, permitting expansion into 1.3 m of initially empty liner. Fully filled liners were recovered from Holes B through E, indicating that the length of recovered intervals exceeded the penetrated distance by a factor of >1.5. A typical down-core logarithmic trend in gamma density profiles, with anomalously low-density values within the upper ∼1 m of each core, suggests that expansion primarily occurred in this upper interval. Thus, we suggest that a simple linear correction is inappropriate. This interpretation is supported by anisotropy of magnetic susceptibility data that indicate vertical stretching in the upper ∼1.5 m of expanded cores. Based on the mean gamma density profiles of cores from Holes M0063C and D, we obtain an expansion function that is used to adjust the depth of each core to conform to its known penetration. The variance in these profiles allows for quantification of uncertainty in the adjusted depth scale. Using a number of bulk 14C dates, we explore how the presence of multiple carbon source pathways leads to poorly constrained radiocarbon reservoir age variability that significantly affects age and sedimentation rate calculations.

Keywords
Paleoclimatology and paleoceanography, Uncertainty quantification, Sedimentation, Statistical methods: Inferential, Magnetic and electrical methods, sediment expansion, radiocarbon, paleomagnetics, age modeling
National Category
Environmental Sciences
Research subject
Baltic and East European studies
Identifiers
urn:nbn:se:sh:diva-32368 (URN)10.1002/2016GC006697 (DOI)000399677600003 ()2-s2.0-85015164849 (Scopus ID)2207/3.1.1/2014 (Local ID)2207/3.1.1/2014 (Archive number)2207/3.1.1/2014 (OAI)
Funder
The Foundation for Baltic and East European Studies, 2207/3.1.1/2014Swedish Research Council, 2012-5114
Available from: 2017-04-10 Created: 2017-04-10 Last updated: 2019-06-25Bibliographically approved
Hardisty, D. S., Riedinger, N., Planavsky, N. J., Asael, D., Andrén, T., Jorgensen, B. B. & Lyons, T. W. (2016). A Holocene History Of Dynamic Water Column Redox Conditions In The Landsort Deep, Baltic Sea. American Journal of Science, 316(8), 713-745
Open this publication in new window or tab >>A Holocene History Of Dynamic Water Column Redox Conditions In The Landsort Deep, Baltic Sea
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2016 (English)In: American Journal of Science, ISSN 0002-9599, E-ISSN 1945-452X, Vol. 316, no 8, p. 713-745Article in journal (Refereed) Published
Abstract [en]

The modern Baltic Sea is the world's largest anthropogenically forced anoxic basin. Using integrated geochemical records collected during Integrated Ocean Drilling Program (IODP) Expedition 347 from the deepest and one of the most reducing sub-basins in the Baltic Sea, Landsort Deep, we explore the degree and frequency of natural anoxia through the Baltic Holocene. A marked decrease in carbon-to-sulfur ratios (C/S) from the cores indicate the transition from the Baltic Ice Lake to the current brackish sea, which occurred about 8.5 kyrs B.P. Following this, laminations throughout sediments recording brackish deposition suggest sustained anoxia or extreme low oxygen, while high molybdenum (Mo) concentrations of >100 ppm and iron (Fe) geochemistry suggest water column sulfide accumulation, or euxinia, that persisted beyond seasonal timescales during deposition of two distinct sapropel units. Sedimentary Mo isotope values range from +1.11 to -0.50 permil, which are distinctly fractionated from modern Baltic seawater (+2.26 to -2.67 parts per thousand) and thus indicate that each of the sapropels experienced only weak and/or oscillatory euxinia-in contrast to the more stable euxinic conditions of more restricted basins. A shift in delta Mo-98 starting above the lower sapropel to a distinctly more negative range suggests particularly weak and oscillatory euxinia, with an enhanced contribution of manganese (Mn) redox cycling to Mo deposition relative to the lower portion of the profile. This conclusion is supported by extreme sedimentary Mn enrichments of up to 15 weight percent. We interpret the combined data to indicate episodic but major Baltic inflow events of saline and oxygenated North Sea water into the anoxic Landsort Deep that limited the concentrations and residence time of water column sulfide and caused episodic oxide deposition. Considering the temporal overlap between the most reducing conditions and periods of redox instability, we hypothesize that major Baltic inflows, as is observed today, lead to short-term instability while simultaneously supporting longer-term Baltic anoxia by strengthening the halocline. Ultimately, our results indicate that periods more reducing than the modern Baltic Sea have occurred naturally over the Holocene, but the characteristic dynamic saline inputs have historically prevented the relatively more widespread and stable anoxia observed in other classic restricted basins and will likely continue to do so.

Keywords
IODP Expedition 347, Baltic Sea, Landsort Deep, paleoredox, molybdenum isotopes
National Category
Environmental Sciences
Research subject
Baltic and East European studies
Identifiers
urn:nbn:se:sh:diva-31074 (URN)10.2475/08.2016.01 (DOI)000384939300001 ()2-s2.0-84990239020 (Scopus ID)
Available from: 2016-11-03 Created: 2016-11-03 Last updated: 2019-08-19Bibliographically approved
Principal InvestigatorAndrén, Thomas
Co-InvestigatorAndrén, Elinor
Coordinating organisation
Södertörn University
Funder
Period
2015-01-01 - 2017-12-31
Keywords [sv]
Östersjö- och Östeuropaforskning
Keywords [en]
Baltic and East European studies
National Category
Environmental Sciences
Identifiers
DiVA, id: project:1792Project, id: 75/2014_OSS

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