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  • 1.
    Andrén, Elinor
    et al.
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Andrén, Thomas
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Syrefria bottnar - orsakade av klimat, människa eller både och?2014Inngår i: Havsutsikt, ISSN 1104-0513, nr 2, s. 12-14Artikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
  • 2.
    Andrén, Elinor
    et al.
    Stockholm University.
    Andrén, Thomas
    Stockholm University.
    Kunzendorf, Helmar
    Risø National Laboratory.
    Holocene history of the Baltic Sea as a background for assessing records of human impact in the sediments of the Gotland Basin2000Inngår i: The Holocene, ISSN 0959-6836, E-ISSN 1477-0911, Vol. 10, s. 687-702Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Sediment cores from the Gotland Basin were studied for their siliceous microfossil assemblages and organic carbon content to compare recent environmental changes in the Baltic Sea with its natural long-term history. Age models were constructed using Pb-210, Cs-137 and corrected and calibrated C-14 dates. The transgression that marks the onset of the Ancylus Lake stage is recorded in the sediments as a small increase in organic carbon coinciding with a peak in diatom abundance and increased diatom diversity. A minor occurrence of brackish-freshwater diatoms is recorded in the Ancylus Lake c. 9950-9750 cal. yr BP (c. 8900-8800 C-14 yr BP), correlating with the onset of the Initial Litorina Sea in the Bornholm Basin. A high-productivity event is recorded in the end of the Post-Litorina Sea and corresponds to the Mediaeval warm event. An alteration in the diatom assemblage contemporaneous with a decrease in organic carbon, interpreted as representing a deterioration in the climate, correlates with the start of the ‘Little Ice Age’ about 850-700 cal. yr BP. A change dated to ad 1950-1960 is probably an effect of increased nutrient availability in the open Baltic Sea. This effect of eutrophication was probably caused by increased discharge of nutrients deriving from fertilizers, as the responding diatom species partly indicate a cold climate rather than a warm one, as would have been expected if this had been only a response to the warmer climate documented during the last 100 years or so.

  • 3.
    Andrén, Elinor
    et al.
    Stockholm University.
    Andrén, Thomas
    Stockholm University.
    Sohlenius, Gustav
    Swedish University of Agriculture.
    The Holocene history of the southwestern Baltic Sea as reflected in a sediment core from the Bornholm Basin2000Inngår i: Boreas, ISSN 0300-9483, E-ISSN 1502-3885, Vol. 29, s. 233-250Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A study of changes in siliceous microfossil assemblages and chemical analyses in a well-dated offshore sediment core from the Bornholm Basin, southwestern Baltic Sea, is carried out with the objective of increasing knowledge of the Holocene history of the area. The core covers about 11 300 calendar years from the brackish phase of the Yoldia Sea stage to the present. The first weak marine influence in the Ancylus Lake stage is recorded about 10 100 cal. yr BP (c. 8900 C-14 BP), indicating a complex transition to the Litorina Sea with different phases of brackish-water inflow. The lithology, organic carbon content and C/N and C/S ratios indicate no major changes in the sedimentary environment during the Litorina-Post-Litorina Sea stages. A high productivity event recorded in the Post-Litorina Sea stage around 950 cal. yr BP correlates with the Medieval warm event. A biostratigraphical change indicating a colder climate is recorded in the sediment at about 800 cal. yr BP, which might mark the beginning of the Little Ice Age.

  • 4.
    Andrén, Elinor
    et al.
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    van Wirdum, Falkje
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Norbäck Ivarsson, Lena
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Lönn, Mikael
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Moros, Matthias
    Leibniz Institute for Baltic Sea Research Warnemünde, Rostock, Germany.
    Andrén, Thomas
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Medieval versus recent environmental conditions in the Baltic Proper, what was different a thousand years ago?2020Inngår i: Palaeogeography, Palaeoclimatology, Palaeoecology, ISSN 0031-0182, E-ISSN 1872-616X, Vol. 555, artikkel-id 109878Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A sediment record from the western Gotland Basin, northwestern Baltic Proper, covering the last 1200 years, was investigated for past changes in climate and the environment using diatoms as a proxy. The aim is to compare the environmental conditions reconstructed during Medieval times with settings occurring the last century under influence of environmental stressors like eutrophication and climate change. The study core records more marine conditions in the western Gotland Basin surface waters during the Medieval Climate Anomaly (MCA; 950–1250C.E.), with a salinity of at least 8 psu compared to the present 6.5 psu. The higher salinity together with a strong summer-autumn stratification caused by warmer climate resulted in extensive long-lasting diatom blooms of Pseudosolenia calcar-avis, effectively enhancing the vertical export of organic carbon to the sediment and contributing to benthic hypoxia. Accordingly, our data support that a warm and dry climate induced the extensive hypoxic areas in the open Baltic Sea during the MCA. During the Little ice Age (LIA; 1400–1700C.E.), the study core records oxic bottom water conditions, decreasing salinity and less primary production. This was succeeded during the 20th century, about 1940, by environmental changes caused by human-induced eutrophication. Impact of climate change is visible in the diatom composition data starting about 1975C.E. and becoming more pronounced 2000C.E., visible as an increase of taxa that thrived in stratified waters during autumn blooms typically due to climate warming.

    Fulltekst (pdf)
    fulltext
  • 5. Andrén, Thomas
    Ancylussjön – fortfarande ett mysterium2003Inngår i: HavsUtsikt, ISSN 1104-0513, nr 3, s. 8-9Artikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
  • 6.
    Andrén, Thomas
    Södertörns högskola, Institutionen för livsvetenskaper, Miljövetenskap. Södertörns högskola, Institutionen för livsvetenskaper, Geografi.
    Baltic Sea Basin, since the latest deglaciation2012Inngår i: Encyclopedia of Lakes and Reservoirs / [ed] Lars Bengtsson, Reginald W. Herschy, Rhodes W. Fairbridge, Dordrecht: Springer Science+Business Media B.V., 2012, s. 95-102Kapittel i bok, del av antologi (Fagfellevurdert)
  • 7. Andrén, Thomas
    Baltic Sea Science Congress 2001 - Preface2005Inngår i: Quaternary International, ISSN 1040-6182, E-ISSN 1873-4553, Vol. 130, nr 1Artikkel i tidsskrift (Fagfellevurdert)
  • 8. Andrén, Thomas
    Baltiska Issjön – eller hur det hela började2003Inngår i: HavsUtsikt, ISSN 1104-0513, nr 1, s. 4-5Artikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
  • 9. Andrén, Thomas
    Littorinahavet – en salt historia2004Inngår i: HavsUtsikt, ISSN 1104-0513, nr 1, s. 8-9Artikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
  • 10. Andrén, Thomas
    Quaternary International: "Baltic Sea Science Congress 2001".2005Collection/Antologi (Annet vitenskapelig)
  • 11.
    Andrén, Thomas
    Stockholm University, Sweden.
    The Younger Dryas - Pre-boreal transition as recorded in vared glacial clay sequences in the north-western Baltic Proper1996Inngår i: GFF, ISSN 1103-5897, E-ISSN 2000-0863, Vol. 118, s. A79-Artikkel i tidsskrift (Fagfellevurdert)
  • 12.
    Andrén, Thomas
    Stockholm University.
    Till stratigraphy and ice recession in the Bothnian Bay1990Doktoravhandling, monografi (Annet vitenskapelig)
  • 13. Andrén, Thomas
    Yoldiahavet – en viktig parentes2003Inngår i: HavsUtsikt, ISSN 1104-0513, nr 2, s. 2-3Artikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
  • 14.
    Andrén, Thomas
    Stockholms universitet.
    Östersjön under åttatusen år: dagens situation är inte ny.2006Inngår i: Östersjön: hot och hopp / [ed] Birgitta Johansson, Stockholm: Forskningsrådet Formas, 2006, s. 41-50Kapittel i bok, del av antologi (Annet (populærvitenskap, debatt, mm))
  • 15.
    Andrén, Thomas
    et al.
    Stockholm University, Sweden.
    Andrén, Elinor
    Uppsala University, Sweden.
    Did The Storegga tsunami affect the Baltic Sea?2001Inngår i: Baltica: an International Yearbook for Quaternary Geology and Palaeogeography, Coastal Morphology and Shore Processes, Marine Geology and Recent Tectonics of the Baltic Sea Area, ISSN 0067-3064, E-ISSN 1648-858X, Vol. 14, s. 115-123Artikkel i tidsskrift (Fagfellevurdert)
  • 16.
    Andrén, Thomas
    et al.
    Stockholm University.
    Andrén, Elinor
    Södertörns högskola, Institutionen för livsvetenskaper.
    Berglund, Björn E.
    Lund University.
    Yu, Shi-Yong
    University of Minnesota.
    New insights on the Yoldia Sea low stand in the Blekinge archipelago, southern Baltic Sea2007Inngår i: GFF, ISSN 1103-5897, E-ISSN 2000-0863, Vol. 129, nr 4, s. 277-285Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    One sediment core from the Jarnavik bay in Blekinge archipelago has been investigated for its content of pollen and diatoms and its chemical properties. Two levels were also dated by radiocarbon. Based on the results the sediment sequence analysed has been divided into three environmental units largely corresponding to the lithology of the sequence. A lowermost unit consisting of weakly varved and homogeneous clay was deposited during the end of the brackish phase of the Yoldia Sea at a moderate water depth. On top of this unit a gyttja-clay unit was deposited. The onset of the deposition of this unit has been dated to c. 11 100 cal. yrs. BP. An increasing organic production and increased terrestrial influence is recorded in the chemical data and a very shallow water depth is indicated in the pollen and diatom flora. These results point to conditions in a bay probably isolated from the Yoldia Sea. A local tentative shore displacement curve have been constructed and it is proposed that this unit represents the low stand at c. -18 m during the Yoldia Sea stage in this part of the Baltic Sea basin. The uppermost unit consists of homogeneous clay with a low content of organic carbon. An increasing water depth is indicated by the composition of both pollen and diatoms. The diatom flora also displays an increase in freshwater species. This environmental change was probably the result of a transgression in the beginning of the Ancylus Lake stage.

  • 17.
    Andrén, Thomas
    et al.
    Södertörns högskola, Institutionen för livsvetenskaper.
    Andrén, Elinor
    Södertörns högskola, Institutionen för livsvetenskaper.
    Nordberg, Kjell
    Omstedt, Anders
    Östersjön förändras ständigt2005Inngår i: Upsala nya tidning, ISSN 1104-0173, nr 8/6Artikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
  • 18.
    Andrén, Thomas
    et al.
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Andrén, Elinor
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Zhang, Rui
    Xiamen University, China.
    Baltic Sea Basin Paleoenvironment: paleoenvironmental evolution of the Baltic Sea Basin through the last glacial cycle2014Rapport (Annet vitenskapelig)
  • 19.
    Andrén, Thomas
    et al.
    Södertörns högskola, Institutionen för livsvetenskaper, Miljövetenskap.
    Barker Jørgensen, Bo
    Aarhus University, Denmark.
    Cotterill, Carlo
    British Geological Survey, UK.
    Morgan, Sally
    University of Leicester, UK.
    IODP Expedition 347:Paleoenvironmental evolution of the Baltic Sea Basin through the last glacial cycle2012Inngår i: ECORD Newsletter, ISSN 2264-1556, nr 19, s. 14-15, 23Artikkel i tidsskrift (Annet vitenskapelig)
    Fulltekst (pdf)
    fulltext
  • 20. Andrén, Thomas
    et al.
    Björck, J
    Johnsen, S
    Correlation of Swedish glacial varves with the Greenland (GRIP) oxygen isotope record1999Inngår i: Journal of Quaternary Science, ISSN 0267-8179, E-ISSN 1099-1417, Vol. 14, nr 4, s. 361-371Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A mean varve thickness curve has been constructed for a part of the Swedish varve chronology from the northwestern Baltic proper. The mean varve thickness curve has been correlated with the delta(18)O record from the GRIP ice-core using the Younger Dryas-Preboreal climate shift. This climate shift was defined by pollen analyses. The Scandinavian ice-sheet responded to a warming at the end of the Younger Dryas, ca. 10 995 to 10 700 clay-varve yr BP. Warming is recorded as a sequence of increasing mean varve thickness and ice-rafted debris suggesting intense calving of the ice front. The Younger Dryas-Preboreal climatic shift is dated to ca. 10 650 clay-varve yr BP, about 40 yr after the final drainage of the Baltic Ice Lake. Both the pollen spectra and a drastic increase in varve thickness reflect this climatic shift. A climate deterioration, correlated with the Preboreal oscillation, is dated to ca. 10 440 to 10 320 clay-varve yr BP and coincides with the brackish water phase of the Yoldia Sea stage. The ages of the climatic oscillations at the Younger Dryas-Preboreal transition show an 875 yr discrepancy compared with the GRIP record, suggesting a large error in the Swedish varve chronology in the part younger than ca. 10 300 clay-varve yr BP.

  • 21.
    Andrén, Thomas
    et al.
    Södertörns högskola, Institutionen för livsvetenskaper, Miljövetenskap. Södertörns högskola, Institutionen för livsvetenskaper, Geografi.
    Björck, S
    Andrén, Elinor
    Södertörns högskola, Institutionen för livsvetenskaper, Miljövetenskap. Södertörns högskola, Institutionen för livsvetenskaper, Geografi.
    Conley, D J
    Lambeck, K
    Zillén, L
    The development of the Baltic Sea basin during the last 130 000 years2011Inngår i: The Baltic Sea Basin / [ed] Jan Harff, Svante Björck, Peer Hoth, Springer Berlin/Heidelberg, 2011, s. 75-97Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 22. Andrén, Thomas
    et al.
    Brunnberg, L
    Miller, U
    PROCEEDINGS FROM THE BALTIC-ICE-LAKE-YOLDIA-SEA-SYMPOSIUM, MARCH 1993: PREFACE1995Inngår i: Quaternary International, ISSN 1040-6182, E-ISSN 1873-4553, Vol. 27, s. 3-3Artikkel i tidsskrift (Annet vitenskapelig)
  • 23.
    Andrén, Thomas
    et al.
    Stockholm University.
    Brunnberg, Lars
    Ringberg, Bertil
    The Reactivated Geochronological Institute in Stockholm - the First Clay-varve Database1995Inngår i: Landscapes and Life: Studies in Honour of Urve Miller / [ed] Ann-Marie Robertsson, Sheila Hicks, Agneta Åkerlund, Jan Risberg & Tony Häckens, Rixensart: Conseil de l'Europe , 1995, s. 213-218Kapittel i bok, del av antologi (Fagfellevurdert)
  • 24.
    Andrén, Thomas
    et al.
    Södertörns högskola, Institutionen för livsvetenskaper, Miljövetenskap.
    Jørgensen, B. B.
    Aarhus Universit, Denmark.
    Cotterill, C.
    British Geological Survey, UK.
    Baltic Sea Basin Paleoenvironment: paleoenvironmental evolution of the Baltic Sea Basin through the last glacial cycle2012Rapport (Annet vitenskapelig)
  • 25.
    Andrén, Thomas
    et al.
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Jørgensen, Bo Barker
    Cotterill, Carol
    Green, Sophie
    IODP expedition 347: Baltic Sea basin paleoenvironment and biosphere2015Inngår i: Scientific Drilling, ISSN 1816-8957, E-ISSN 1816-3459, Vol. 20, s. 1-12Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The Integrated Ocean Drilling Program (IODP) expedition 347 cored sediments from different settings of the Baltic Sea covering the last glacial–interglacial cycle. The main aim was to study the geological development of the Baltic Sea in relation to the extreme climate variability of the region with changing ice cover and major shifts in temperature, salinity, and biological communities. Using the Greatship Manisha as a European Consortium for Ocean Research Drilling (ECORD) mission-specific platform, we recovered 1.6 km of core from nine sites of which four were additionally cored for microbiology. The sites covered the gateway to the North Sea and Atlantic Ocean, several sub-basins in the southern Baltic Sea, a deep basin in the central Baltic Sea, and a river estuary in the north.

    The waxing and waning of the Scandinavian ice sheet has profoundly affected the Baltic Sea sediments. During theWeichselian, progressing glaciers reshaped the submarine landscape and displaced sedimentary deposits from earlier Quaternary time. As the glaciers retreated they left a complex pattern of till, sand, and lacustrine clay, which in the basins has since been covered by a thick deposit of Holocene, organic-rich clay. Due to the stratified water column of the brackish Baltic Sea and the recurrent and widespread anoxia, the deeper basins harbor laminated sediments that provide a unique opportunity for high-resolution chronological studies.

    The Baltic Sea is a eutrophic intra-continental sea that is strongly impacted by terrestrial runoff and nutrient fluxes. The Holocene deposits are recorded today to be up to 50m deep and geochemically affected by diagenetic alterations driven by organic matter degradation. Many of the cored sequences were highly supersaturated with respect to methane, which caused strong degassing upon core recovery. The depth distributions of conservative sea water ions still reflected the transition at the end of the last glaciation from fresh-water clays to Holocene brackish mud. High-resolution sampling and analyses of interstitial water chemistry revealed the intensive mineralization and zonation of the predominant biogeochemical processes. Quantification of microbial cells in the sediments yielded some of the highest cell densities yet recorded by scientific drilling.

    Fulltekst (pdf)
    fulltext
  • 26.
    Andrén, Thomas
    et al.
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Jørgensen, Bo Barker
    Cotterill, Carol
    Green, Sophie
    Andrén, Elinor
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Baltic Sea Basin Paleoenvironment: Expedition 347 of the mission-specific drilling platform  from and to Kiel, Germany Sites M0059–M0067  12 September–1 November 20132015Rapport (Annet vitenskapelig)
  • 27.
    Andrén, Thomas
    et al.
    Södertörns högskola, Institutionen för livsvetenskaper.
    Jørgensen, Bo Barker
    Aarhus University, Aarhus, Denmark.
    Cotterill, Carol
    ECORD Science Operator, British Geological Survey, Murchison House, Edinburgh, UK.
    Morgan, Sally
    University of Leicester, Leicester, UK.
    IODP Expedition 347: Paleoenvironmental evolution of the Baltic Sea Basin trough the last glacial cycle2012Inngår i: ECORD Newsletter, nr 19 October, s. 14-15+ s.23Artikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
  • 28.
    Andrén, Thomas
    et al.
    Stockholm University.
    Lindeberg, Greger
    A shallow refraction seismic survey at Björkö eastern Sweden: a pilot study1997Inngår i: Environment and Vikings: with special reference to Birka / [ed] Björn Ambrosiani; Helen Clarke; Tony Hackens; Ann-Marie Hansson; Brigitta Johansson, Rixensart: Conseil de l'Europe , 1997, s. 175-188Konferansepaper (Fagfellevurdert)
  • 29. Andrén, Thomas
    et al.
    Lindeberg, Greger
    Andrén, Elinor
    Evidence of the final drainage of the Baltic Ice Lake and the brackish phase of the Yoldia Sea in glacial varves from the Baltic Sea2002Inngår i: Boreas, ISSN 0300-9483, E-ISSN 1502-3885, Vol. 31, s. 226-238Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A clay-varve chronology based on 14 cross-correlated varve graphs from the Baltic Sea and a mean varve thickness curve has been constructed. This chronology is correlated with the Swedish Time Scale and covers the time span 11 530 to 10 250 varve years BP. Two cores have been analysed for grain size, chemistry, content of diatoms and changes in colour by digital colour analysis. The final drainage of the Baltic Ice Lake is dated to c. 10800 varve years BP and registered in the cores analysed as a decrease in the content of clay. This event can be correlated with atmospheric D 14 C content and might have resulted in an increase in these values recorded between 11565 and 11545 years BP. The results of the correlation between the varve chronology from the Baltic Sea, the Greenland GRIP ice core and the atmospheric D 14 C record indicate that c. 760 years are missing in the Swedish Time Scale in the part younger than c. 10 250 varve years BP. A change in colour from a brownish to grey varved glacial clay recorded c. 10 770 varve years BP is found to be the result of oxygen deficiency due to an increase in the rate of sedimentation in the early Preboreal. The first brackish influence is recorded c. 10 540 varve years BP in the northwestern Baltic Sea and some 90 years later in the eastern Gotland Basin.

  • 30.
    Andrén, Thomas
    et al.
    Stockholm University.
    Risberg, Jan
    Late Quaternary development of the north-western Baltic Proper: An introduction1994Inngår i: Laminated sediments: symposium held at the European University Centre for Cultural Heritage, Ravello, June, 1991 / [ed] Sheila Hicks; Urve Miller; Matti Saarnisto, Rixensart: Conseil de l'Europe , 1994, s. 35-43Konferansepaper (Fagfellevurdert)
  • 31.
    Andrén, Thomas
    et al.
    Södertörns högskola, Institutionen för livsvetenskaper, Miljövetenskap. Södertörns högskola, Institutionen för livsvetenskaper, Geografi.
    Rytkönen, Paulina
    Södertörns högskola, Institutionen för livsvetenskaper, Måltidskunskap.
    Vinlandet Sverige - konsumtionen, produktionen och framtida förutsättningar2011Inngår i: Ymer, ISSN 0044-0477, s. 121-146Artikkel i tidsskrift (Annet vitenskapelig)
  • 32.
    Andrén, Thomas
    et al.
    Stockholm University.
    Sohlenius, Gustav
    Clay-varve chronology and magnetic stratigraphy in the north-western Baltic Proper1995Inngår i: Proceedings of the Third Marine Geological Conference "The Baltic" / [ed] Józef Edward Mojski, Warszawa: Państwowy Inst. Geologiczny , 1995, s. 78-83Konferansepaper (Fagfellevurdert)
  • 33. Andrén, Thomas
    et al.
    Sohlenius, Gustav
    Late Quaternary development of the north-western Baltic Proper: Results from the clay-varve investigation1995Inngår i: Quaternary International, ISSN 1040-6182, E-ISSN 1873-4553, Vol. 27, s. 5-10Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Within the project "Late Quaternary development of the north-western Baltic Proper" a total of 36 piston core samples have been collected. The results presented in this study are based on analyses of 7 cores with emphasis on the late glacial part of the sequence. The varved glacial clay sequences have been analyzed for calcareous micro-fossils and mineral magnetic properties as well as measurements of clay-varves. The results from these analyses indicate that there is a close correlation between the occurrence of brackish water ostracods and foraminifera and a distinct change in the mineral magnetic parameters. The lithological composition of the clay-varves also differs in this sequence. The duration of this marine phase of the Yoldia Sea stage is 60 to 120 clay-varve years. It is concluded that correlations between the cores can be made using fossil assemblages and mineral magnetic parameters. It has not yet been possible, however, to make any reliable clay-varve connections.

  • 34.
    Andrén, Thomas
    et al.
    Stockholm University.
    Wannäs, Kjell
    Late Quaternary development of the Bornholm Gatt1988Inngår i: The Baltic Sea: papers prepared for a colloquium on Baltic Sea marine geology in Parainen, Finland, 27-29, May 1987 / [ed] Winterhalter, Boris, Espoo: Geologian tutkimuskeskus , 1988, s. 23-30Konferansepaper (Fagfellevurdert)
  • 35. Bianchi, Thomas S
    et al.
    Engelhaupt, Erika
    Westman, Per
    Andrén, Thomas
    Rolff, Carl
    Elmgren, Ragnar
    Cyanobacterial blooms in the Baltic Sea: Natural or human-induced?2000Inngår i: Limnology and Oceanography, ISSN 0024-3590, E-ISSN 1939-5590, Vol. 45, nr 3, s. 716-726Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Massive summer blooms of nitrogen-fixing cyanobacteria have been documented in the Baltic Sea since the 19th century, but are reported to have increased in frequency, biomass, and duration in recent decades-presumably in response to the well-documented anthropogenic eutrophication of the Baltic. Here, we present an 8,000-yr record of fossil cyanobacterial pigments, diatom microfossil assemblages, and delta(15)N variations in sediment cores from the Baltic proper. This record indicates that nitrogen-living cyanobacterial blooms are nearly as old as the present brackish water phase of the Baltic Sea, starting as far back as ca. 7000 B.P.-soon after the former freshwater Ancylus Lake turned into the brackish Litorina Sea. Demonstration of cyanobacterial blooms in the Baltic prior to the greatly increased anthropogenic nutrient inputs of the 20th century is important for setting realistic goals when trying to reduce the magnitude of present brooms. Our results suggest that the presently predominating nitrogen (N) limitation of phytoplankton in the Baltic Sea proper is not man-induced, but a natural phenomenon, which has endured for some 7,000 yr. These cyanobacterial blooms were possibly initiated by increased availability of phosphorus (P)-from inflow of P-rich seawater and increased P release from sediments-during periods of deep-water anoxia, caused by the establishment of salinity stratification. Efforts to restore the Baltic proper to a more oligotrophic and natural condition should take into account that nitrogen-fixing cyanobacterial blooms are a characteristic, natural feature of this sea.

  • 36. Bindler, Richard
    et al.
    Renberg, Ingemar
    Rydberg, Johan
    Andrén, Thomas
    Södertörns högskola, Institutionen för livsvetenskaper, Geografi. Södertörns högskola, Institutionen för livsvetenskaper, Miljövetenskap.
    Widespread waterborne pollution in central Swedish lakes and the Baltic Sea from pre-industrial mining and metallurgy2009Inngår i: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 157, s. 2132-2141Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Metal pollution is viewed as a modern problem that began in the 19th century and accelerated through the 20th century; however, in many parts of the globe this view is wrong. Here, we studied past waterborne metal pollution in lake sediments from the Bergslagen region in central Sweden, one of many historically important mining regions in Europe. With a focus on lead (including isotopes), we trace mining impacts from a local scale, through a 120-km-long river system draining into Malaren - Sweden’s third largest lake, and finally also the Baltic Sea. Comparison of sediment and peat records shows that pollution from Swedish mining was largely waterborne and that atmospheric deposition was dominated by long-range transport from other regions. Swedish ore lead is detectable from the 10th century, but the greatest impact occurred during the 16th-18th centuries with improvements occurring over recent centuries, i.e., historical pollution > modern industrial pollution.

  • 37. Björck, Jonas
    et al.
    Andrén, Thomas
    Wastegård, Stefan
    Possnert, Göran
    Schoning, Kristian
    An event stratigraphy for the Last Glacial-Holocene transition in eastern middle Sweden: results from investigations of varved clay and terrestrial sequences2002Inngår i: Quaternary Science Reviews, ISSN 0277-3791, E-ISSN 1873-457X, Vol. 21, nr 12/13, s. 1489-1501Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents an event stratigraphy for the Last Glacial-Holocene transition in eastern middle Sweden. The event stratigraphy for eastern middle Sweden comprises ten events and covers the time-span from ca 12,900 to 10,200 cal yr BP. The local event stratigraphy has been linked to the GRIP isotopic event stratigraphy by different correlations. The onset of the Younger Dryas is dated to 12,650 cal yr BP. This cold event lasted for ca 1125 cal yr in the area. The Vedde Ash (ca 12,000 cal yr BP) has been recorded in two terrestrial sequences, which makes it possible to exactly link the event stratigraphy to the GRIP ice-core and to marine cores in the North Atlantic region. The final drainage of the Baltic Ice Lake has been dated to ca 11,560 cal yr BP, which predates the Younger Dryas/Preboreal climatic boundary with ca 35 yr. An early Holocene cold event has been detected both in terrestrial and varved clay sequences at ca 11,305-11,185 cal yr BP. This cold event coincides almost exactly with a brackish water phase in the Baltic Sea. A previously unrecorded early Holocene tephra horizon has been found in lacustrine sediments at ca 10,200 cal yr BP.

  • 38. Björck, S.
    et al.
    Andrén, Thomas
    Södertörns högskola, Institutionen för livsvetenskaper.
    Jensen, J. B.
    An attempt to resolve the partly conflicting data and ideas on the Ancylus - Littorina transition2008Inngår i: Proceedings of the workshop "Relative sea level changes - from subsiding to uplifting coasts" / [ed] Szymon Uścinowicz, Joanna Zachowicz, 2008, s. 21-26Konferansepaper (Annet vitenskapelig)
  • 39.
    Dahl, Martin
    et al.
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Gullström, Martin
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Bernabeu, I.
    Consejo Superior de Investigaciones Científicas (CEAB‐CSIC), Spain.
    Serrano, O.
    Consejo Superior de Investigaciones Científicas (CEAB‐CSIC),Spain, Edith Cowan University, Australia.
    Leiva-Dueñas, C.
    Aarhus University, Denmark.
    Linderholm, H. W.
    University of Gothenburg, Sweden.
    Asplund, M. E.
    University of Gothenburg, Sweden.
    Björk, M.
    Stockholm University, Sweden.
    Ou, T.
    University of Gothenburg, Sweden.
    Svensson, J. R.
    University of Gothenburg, Sweden.
    Andrén, Elinor
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Andrén, Thomas
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Bergman, S.
    UiT—The Arctic University of Norway, Norway.
    Braun, Sara
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Eklöf, A.
    Stockholm University, Sweden.
    Ežerinskis, Z.
    Center for Physical Sciences and Technology, Lithuania.
    Garbaras, A.
    Center for Physical Sciences and Technology, Lithuania.
    Hällberg, P.
    Stockholm University, Sweden.
    Löfgren, E.
    Stockholm University, Sweden.
    Kylander, M. E.
    Stockholm University, Sweden.
    Masqué, P.
    Edith Cowan University, Australia, PrincipalityofMonaco,Monaco.
    Šapolaitė, J.
    Center for Physical Sciences and Technology, Lithuania.
    Smittenberg, R.
    Stockholm University, Sweden, Principality of Monaco, Monaco.
    Mateo, M. A.
    Consejo Superior de Investigaciones Científicas (CEAB‐CSIC), Spain, Edith Cowan University, Australia.
    A 2,000-Year Record of Eelgrass (Zostera marina L.): Colonization Shows Substantial Gains in Blue Carbon Storage and Nutrient Retention2024Inngår i: Global Biogeochemical Cycles, ISSN 0886-6236, E-ISSN 1944-9224, Vol. 38, nr 3, artikkel-id e2023GB008039Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Assessing historical environmental conditions linked to habitat colonization is important for understanding long-term resilience and improving conservation and restoration efforts. Such information is lacking for the seagrass Zostera marina, an important foundation species across cold-temperate coastal areas of the Northern Hemisphere. Here, we reconstructed environmental conditions during the last 14,000 years from sediment cores in two eelgrass (Z. marina) meadows along the Swedish west coast, with the main aims to identify the time frame of seagrass colonization and describe subsequent biogeochemical changes following establishment. Based on vegetation proxies (lipid biomarkers), eelgrass colonization occurred about 2,000 years ago after geomorphological changes that resulted in a shallow, sheltered environment favoring seagrass growth. Seagrass establishment led to up to 20- and 24-fold increases in sedimentary carbon and nitrogen accumulation rates, respectively. This demonstrates the capacity of seagrasses as efficient ecosystem engineers and their role in global change mitigation and adaptation through CO2 removal, and nutrient and sediment retention. By combining regional climate projections and landscape models, we assessed potential climate change effects on seagrass growth, productivity and distribution until 2100. These predictions showed that seagrass meadows are mostly at risk from increased sedimentation and hydrodynamic changes, while the impact from sea level rise alone might be of less importance in the studied area. This study showcases the positive feedback between seagrass colonization and environmental conditions, which holds promise for successful conservation and restoration efforts aimed at supporting climate change mitigation and adaptation, and the provision of several other crucial ecosystem services. © 2024. The Authors.

  • 40.
    Hardisty, Dalton S.
    et al.
    University of California-Riverside, Riverside California, USA .
    Riedinger, Natascha
    Oklahoma State University, Stillwater, Oklahoma, USA .
    Planavsky, Noah J.
    Yale University, New Haven, Connecticut, USA.
    Asael, Dan
    Yale University, New Haven, Connecticut, USA.
    Andrén, Thomas
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Jorgensen, Bo B.
    Aarhus University, Aarhus C, Denmark .
    Lyons, Timothy W.
    University of California-Riverside, Riverside California, USA .
    A Holocene History Of Dynamic Water Column Redox Conditions In The Landsort Deep, Baltic Sea2016Inngår i: American Journal of Science, ISSN 0002-9599, E-ISSN 1945-452X, Vol. 316, nr 8, s. 713-745Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 41.
    Hyttinen, O.
    et al.
    University of Helsinki, Helsinki, Finland.
    Kotilainen, A. T.
    Geological Survey of Finland (GTK), Espoo, Finland.
    Virtasalo, J. J.
    Geological Survey of Finland (GTK), Espoo, Finland.
    Kekäläinen, P.
    University of Helsinki, Helsinki, Finland / WSP Finland Oy, Helsinki, Finland.
    Snowball, I.
    Uppsala universitet.
    Obrochta, S.
    Akita University, Akita City, Japan.
    Andrén, Thomas
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Holocene stratigraphy of the Ångermanälven River estuary, Bothnian Sea2017Inngår i: Geo-Marine Letters, ISSN 0276-0460, E-ISSN 1432-1157, Vol. 37, nr 3, s. 273-288Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study explores the Holocene depositional succession at the IODP Expedition 347 sites M0061 and M0062 in the vicinity of the Ångermanälven River estuary in the Bothnian Sea sector of the Baltic Sea in northern Scandinavia. Site M0061 is located in a coastal offshore setting (87.9 m water depth), whereas site M0062 is fully estuarine (69.3 m water depth). The dataset comprises acoustic profiles and sediment cores collected in 2007 and late 2013 respectively. Three acoustic units (AUs) were recognized. Lowermost AU1 is interpreted as a poorly to discontinuous stratified glaciofluvial deposit, AU2 as a stratified conformable drape of glaciolacustrine origin, and AU3 as a poorly stratified to stratified mud drift. A strong truncating reflector separates AU2 and AU3. Three lithological units (LUs) were defined in the sediment cores. LU1 consists of glaciofluvial sand and silt gradating into LU2, which consists of glaciolacustrine varves. A sharp contact interpreted as a major unconformity separates LU2 from the overlying LU3 (brackish-water mud). In the basal part of LU3, one debrite (site M0061) or two debrites (site M0062) were recognized. Information yielded from sediment physical properties (magnetic susceptibility, natural gamma ray, dry bulk density), geochemistry (total carbon, total organic carbon, total inorganic carbon and nitrogen), and grain size support the LU division. The depositional succession was formally subdivided into two alloformations: the Utansjö Alloformation and overlying Hemsön Alloformation; the Utansjö Alloformation was further subdivided into two lithostratigraphic formations: the Storfjärden and Åbordsön formations. The Storfjärden (sandy outwash) and Åbordsön (glaciolacustrine rhythmite) formations represent a glacial retreat systems tract, which started at ca. 10.6 kyr BP. Their deposition was mainly controlled by meltwater from the retreating ice margin, glacio-isostatic land uplift and the regressive (glacial) lake level. The Hemsön Alloformation (organic-rich brackish-water mud) represents a period of forced regression, starting possibly at ca. 9.5 kyr BP. At about 7 kyr BP, brackish water reached the study area as a result of the mid-Holocene marine flooding of the Baltic Sea Basin, but the rapid land uplift soon surpassed the associated (Littorina) transgression. Changed near-bottom current patterns, caused by the establishment of a permanent halocline, and the reduced sediment consistency caused by increased organic deposition resulted in a sharp and erosional base of the brackish-water mud. Estuarine processes and salinity stratification at site M0062 started to play a more important role. This study applies a combined allostratigraphic and lithostratigraphic approach over the conventional Baltic Sea stages. This approach makes it more straightforward to study this Baltic Sea deglaciation–postglacial sequence and compare it to other formerly glaciated shallow sea estuaries.

  • 42.
    Hyttinen, O.
    et al.
    University of Helsinki, Helsinki, Finland.
    Quintana Krupinski, N.
    Lund University.
    Bennike, O.
    Geological Survey of Denmark and Greenland, Aarhus, Denmark.
    Wacker, L.
    ETH Zürich, Zürich, Switzerland.
    Filipsson, H. L.
    Lund University.
    Obrochta, S.
    Akita University, Akita, Japan.
    Jensen, J. B.
    Geological Survey of Denmark and Greenland, Aarhus, Denmark.
    Lougheed, B.
    Université Paris Saclay, Paris, France.
    Ryabchuk, D.
    A.P. Karpinsky Russian Geological Research Institute, Saint Petersburg, Russia.
    Passchier, S.
    Montclair State University, Montclair, USA.
    Snowball, I.
    Uppsala University.
    Herrero-Bervera, E.
    University of Hawai'i at Mānoa, Honolulu, USA.
    Andrén, Thomas
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Kotilainen, A. T.
    Geological Survey of Finland, Espoo, Finland.
    Deglaciation dynamics of the Fennoscandian Ice Sheet in the Kattegat, the gateway between the North Sea and the Baltic Sea Basin2021Inngår i: Boreas, ISSN 0300-9483, E-ISSN 1502-3885, Vol. 50, nr 2, s. 351-368Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents an age–depth model based on an ultra-high-resolution, 80-m-thick sedimentary succession from a marine continental shelf basin, the Kattegat. This is an area of dynamic deglaciation of the Fennoscandian Ice Sheet during the Late Pleistocene. The Kattegat is also a transitional area between the saline North Sea and the brackish Baltic Sea. As such, it records general development of currents and exchange between these two systems. Data for the succession were provided through the Integrated Ocean Drilling Program Site M0060. The site indicates onset of deglaciation at c. 18 ka BP and relatively continuous sedimentation until 13 ka BP. At this point, sediments record a hiatus until c. 9–7 ka BP. The uppermost sedimentary unit contains redeposited material, but it is estimated to represent only the last c. 9–7 ka BP. The age–depth model is based on 17 select, radiocarbon-dated samples and is integrated with a set of physical and chemical proxies. The integrated records provide novel constraints on the timing of major palaeoenvironmental changes, such as the transition from glaciomarine proximal to glaciomarine distal and marine conditions, and their connections to known major events and processes in the region and the North Atlantic. Depositional evidence specifically documents connections between the Fennoscandian Ice Sheet behaviour and atmospheric and oceanic warming. Glacial retreat may have also depended on topographic factors such as changes in basin width and depth, linked to relative sea level changes and land uplift. The results indicate an early response of the Fennoscandian Ice Sheet to changing climate, and the ice sheet's possible influence on oceanic circulation during the Late Pleistocene deglaciation.

  • 43.
    Jakobsson, Martin
    et al.
    Stockholm University.
    Andrén, Thomas
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Gyllencreutz, Richard
    Stockholm University.
    Noormets, Riko
    UNIS Univ Ctr Svalbard, Longyearbyen, Svalbard.
    Sturkell, Erik
    University of Gothenburg.
    In memoriam of Tom Flodén: obituary2017Inngår i: GFF, ISSN 1103-5897, E-ISSN 2000-0863, Vol. 139, nr 3, s. 241-242Artikkel i tidsskrift (Annet vitenskapelig)
  • 44. Jakobsson, Martin
    et al.
    Björck, Svante
    Alm, Göran
    Andrén, Thomas
    Stockholms universitet.
    Lindeberg, Greger
    Svensson, Nils-Olof
    Reconstructing the Younger Dryas ice dammed lake in the Baltic Basin: Bathymetry, area and volume2007Inngår i: Global and Planetary Change, ISSN 0921-8181, E-ISSN 1872-6364, Vol. 57, nr 3/4, s. 355-370Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A digital 3D-reconstruction of the Baltic Ice Lake’s (BIL) configuration during the termination of the Younger Dryas cold phase (ca. 11700 cal. yr BP) was compiled using a combined bathymetric-topographic Digital Terrain Model (DTM), Scandinavian ice sheet limits, Baltic Sea Holocene bottom sediment thickness information, and a paleoshoreline database maintained at the Lund University. The bathymetric-topographic DTM, assembled from publicly available data sets, has a resolution of 500 X 500 m on Lambert Azimuthal Equal Area projection allowing area and volume calculations of the BIL to be made with an unprecedented accuracy. When the damming Scandinavian ice sheet margin eventually retreated north of Mount Billingen, the high point in terrain of Southern central Sweden bordering to lower terrain further to the north, the BIL was catastrophically drained resulting in a 25 m drop of the lake level. With our digital reconstruction, we estimate that approximately 7800 km(3) of water drained during this event and that the ice dammed lake area was reduced by ca. 18%. Building on previous results suggesting drainage over 1 to 2 years, our lake volume calculations imply that the freshwater flux to the contemporaneous sea in the west was between about 0.12 and 0.25 Sv. The BIL reconstruction provides new detailed information on the paleogeography in the area of southern Scandinavia, both before and after the drainage event, with implications for interpretations of geological records concerning the post-glacial environmental development.

  • 45.
    Jørgensen, Bo Barker
    et al.
    Aarhus University, Aarhus, Denmark.
    Andrén, Thomas
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Marshall, Ian P G
    Aarhus University, Aarhus, Denmark.
    Sub-seafloor biogeochemical processes and microbial life in the Baltic Sea2020Inngår i: Environmental Microbiology, ISSN 1462-2912, E-ISSN 1462-2920, Vol. 22, nr 5, s. 1688-1706Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    The post-glacial Baltic Sea has experienced extreme changes that are archived today in the deep sediments. IODP Expedition 347 retrieved cores down to 100 m depth and studied the climate history and the deep biosphere. We here review the biogeochemical and microbiological highlights and integrate these with other studies from the Baltic seabed. Cell numbers, endospore abundance and organic matter mineralization rates are extremely high. A 100-fold drop in cell numbers with depth results from a small difference between growth and mortality in the ageing sediment. Evidence for growth derives from a D:L amino acid racemization model, while evidence for mortality derives from the abundance and potential activity of lytic viruses. The deep communities assemble at the bottom of the bioturbated zone from the founding surface community by selection of organisms suited for life under deep sediment conditions. The mean catabolic per-cell rate of microorganisms drops steeply with depth to a life in slow-motion, typical for the deep biosphere. The subsurface life under extreme energy limitation is facilitated by exploitation of recalcitrant substrates, by biochemical protection of nucleic acids and proteins, and by repair mechanisms for random mismatches in DNA or damaged amino acids in proteins. This article is protected by copyright. All rights reserved.

  • 46.
    Katrantsiotis, Christos
    et al.
    Umeå University, Sweden.
    Dahl, Martin
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Palm, Veronica
    Södertörns högskola, Institutionen för historia och samtidsstudier, MARIS (Marinarkeologiska forskningsinstitutet). Västerviks Museum, Sweden.
    Rönnby, Johan
    Södertörns högskola, Institutionen för historia och samtidsstudier, Arkeologi. Södertörns högskola, Institutionen för historia och samtidsstudier, MARIS (Marinarkeologiska forskningsinstitutet).
    Andrén, Thomas
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Andrén, Elinor
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Holocene relative sea level changes in the Vastervik-Gamlebyviken region on the southeast coast of Sweden, southern Baltic Sea2023Inngår i: Boreas, ISSN 0300-9483, E-ISSN 1502-3885, Vol. 52, nr 2, s. 206-222Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We reconstruct the Holocene shore displacement of the Vastervik-Gamlebyviken area on the southeast coast of Sweden, characterised by a maritime cultural landscape and archaeological significance since the Mesolithic. Sediment cores were retrieved from four lake basins that have been raised above sea level due to the postglacial land uplift and eustatic sea level changes after the melting of the Fennoscandian Ice Sheet. The cores were radiocarbon dated and analysed for loss on ignition and diatoms. The isolation thresholds of the basins were determined using LiDAR data. The results provide evidence for the initiation of the first Littorina Sea transgression in this area at 8.5 thousand calibrated years before present (cal. ka BP). A relative sea level rise by similar to 7 m a.s.l. is recorded between 8.0 and 7.5 cal. ka BP with a highstand at similar to 22 m a.s.l. between 7.5 and 6.2 cal. ka BP. These phases coincide with the second and third Littorina Sea transgressions, respectively, in the Blekinge area, southern Sweden and are consistent with the final deglaciation of North America. After 6.2 cal. ka BP, the relative sea level dropped below 22 m a.s.l., and remained at similar to 20 m a.s.l. until 4.6 cal. ka BP coinciding with the fourth Littorina Sea transgression in Blekinge. From 4.6 to 4.2 cal. ka BP, the shore displacement shows a regression rate of 10 mm a(-1) followed by a slowdown with a mean value of 4.6 mm a(-1) until 1.6 cal. ka BP, when the relative sea level dropped below 3.3 m a.s.l. The Middle to Late Holocene highstand and other periods of minor sea level transgressions and/or higher salinity between 6.2 and 1.7 cal. ka BP are attributed to a combination of warmer climate and higher inflow of saline waters in the southern Baltic Sea due to stronger westerlies, caused by variations in the North Atlantic atmospheric patterns.

    Fulltekst (pdf)
    fulltext
  • 47.
    Kotthoff, U.
    et al.
    University of Hamburg.
    Groeneveld, J.
    University of Bremen.
    Ash, J.L.
    UCLA.
    Fanget, A.-S.
    Aarhus University, Université de Perpignan.
    Krupinski, N.Q.
    Lund University.
    Peyron, O.
    University of Montpellier.
    Stepanova, A.
    Texas A&M University.
    Warnock, J.
    Indiana University of Pennsylvania.
    Van Helmond, N. A. G. M.
    Utrecht University.
    Passey, B.H.
    University of Michigan.
    Clausen, O.R.
    Aarhus University.
    Bennike, O.
    Geological Survey of Denmark and Greenland.
    Andrén, Elinor
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Granoszewski, W.
    Polish Geological Institute-National Research Institute Krakow.
    Andrén, Thomas
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Filipsson, H.L.
    Lund University.
    Seidenkrantz, M.-S.
    Aarhus University.
    Slomp, C.P.
    Utrecht University.
    Bauersachs, T.
    Christian-Albrechts-Universität.
    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)2017Inngår i: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 14, s. 5607-5632Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 48. Kunzendorf, Helmar
    et al.
    Voss, Maren
    Brenner, Wolfram
    Andrén, Thomas
    Stockholm University, Sweden.
    Vallius, Henry
    Molybedeneum in sediments of central Balric Sea as an indicator for algal blooms2001Inngår i: Baltica: an International Yearbook for Quaternary Geology and Palaeogeography, Coastal Morphology and Shore Processes, Marine Geology and Recent Tectonics of the Baltic Sea Area, ISSN 0067-3064, E-ISSN 1648-858X, Vol. 14, s. 123-130Artikkel i tidsskrift (Fagfellevurdert)
  • 49.
    Mhatre, Snehit S
    et al.
    Aarhus University, Aarhus, Denmark / University of Southern Denmark, Odense, Denmark.
    Kaufmann, Stefan
    Aarhus University, Aarhus, Denmark.
    Marshall, Ian P G
    Aarhus University, Aarhus, Denmark.
    Obrochta, Stephen
    Akita University, Akita City, Japan.
    Andrén, Thomas
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Jørgensen, Bo Barker
    Aarhus University, Aarhus, Denmark.
    Lomstein, Bente Aa
    Aarhus University, Aarhus, Denmark.
    Microbial biomass turnover times and clues to cellular protein repair in energy-limited deep Baltic Sea sediments2019Inngår i: FEMS Microbiology Ecology, ISSN 0168-6496, E-ISSN 1574-6941, Vol. 95, nr 6, artikkel-id fiz068Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The discovery of active microbial life deeply buried beneath the seafloor has opened important questions: how do microorganisms cope with extreme energy limitation, what is their metabolic activity, and how do they repair damages to essential biomolecules? We used a D:L-amino acid model to calculate microbial biomass turnover times. We used a metagenome and metatranscriptome analysis to investigate the distribution of the gene that encodes Protein-L-iso aspartate(D-aspartate) O-methyltransferase (PCMT), an enzyme which recognizes damaged L-isoapartyl and D-aspartyl residues in proteins and catalyzes their repair. Sediment was retrieved during the Integrated Ocean Drilling Program (IODP) Expedition 347 from Landsort Deep and the Little Belt in the Baltic Sea. The study covers the period from the Baltic Ice Lake ca. 13 000 years ago to the present. Our results provide new knowledge on microbial biomass turnover times and protein repair in relation to different regimes of organic matter input. For the first time, we show that the PCMT gene was widely distributed and expressed among phylogenetically diverse groups of microorganisms. Our findings suggest that microbial communities are capable of repairing D-amino acids within proteins using energy obtained from the degradation of a mixture of labile compounds in microbial necromass and more recalcitrant organic matter.

  • 50.
    Moberg, Christina
    et al.
    EASAC; KTH, Sverige.
    Wolrath Söderberg, Maria
    Södertörns högskola, Institutionen för kultur och lärande, Retorik.
    Sandberg, Linn
    Södertörns högskola, Institutionen för kultur och lärande, Genusvetenskap.
    Lindblad, Inger
    Södertörns högskola, Institutionen för samhällsvetenskaper, Socialt arbete.
    Sjöholm, Cecilia
    Södertörns högskola, Institutionen för kultur och lärande, Estetik.
    Gullström, Martin
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Lalander, Rickard
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Andrén, Elinor
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Vallström, Maria
    Södertörns högskola, Institutionen för historia och samtidsstudier, Etnologi.
    Bonow, Madeleine
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Andrén, Thomas
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Porseryd, Tove
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Grahn, Mats
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Karlholm, Dan
    Södertörns högskola, Institutionen för kultur och lärande, Konstvetenskap.
    Smith, Nicholas
    Södertörns högskola, Institutionen för kultur och lärande, Filosofi.
    Lehtilä, Kari
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Cederberg, Carl
    Södertörns högskola, Institutionen för kultur och lärande, Centrum för praktisk kunskap.
    Svärd, Veronica
    Södertörns högskola, Institutionen för samhällsvetenskaper, Socialt arbete.
    Gunnarsson Payne, Jenny
    Södertörns högskola, Institutionen för historia och samtidsstudier, Etnologi.
    Bornemark, Jonna
    Södertörns högskola, Institutionen för kultur och lärande, Centrum för praktisk kunskap.
    Kaun, Anne
    Södertörns högskola, Institutionen för kultur och lärande, Medie- och kommunikationsvetenskap.
    Bergkvist, Anna-Mia
    Södertörns högskola, Institutionen för kultur och lärande, Centrum för praktisk kunskap.
    Gunnarson, Martin
    Södertörns högskola, Institutionen för kultur och lärande, Centrum för praktisk kunskap.
    Persson, Sara
    Södertörns högskola, Institutionen för samhällsvetenskaper, Företagsekonomi.
    Jacobsson, Ellen
    Södertörns högskola, Institutionen för kultur och lärande, Centrum för praktisk kunskap.
    Spånberger Weitz, Ylva
    Södertörns högskola, Institutionen för samhällsvetenskaper, Socialt arbete.
    Diderichsen, Öjvind
    Södertörns högskola, Lärarutbildningen, Lärarutbildning och Estetiska lärprocesser.
    Gilek, Michael
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Garrison, Julie
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Pröckl, Maria
    Södertörns högskola, Institutionen för kultur och lärande, Centrum för praktisk kunskap.
    Janzén, Therese
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Dobers, Peter
    Södertörns högskola, Institutionen för samhällsvetenskaper, Företagsekonomi.
    Dinnétz, Patrik
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Bydler, Charlotte
    Södertörns högskola, Institutionen för kultur och lärande, Konstvetenskap.
    Westerberg, Charles
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Elmersjö, Magdalena
    Södertörns högskola, Institutionen för samhällsvetenskaper, Socialt arbete.
    Bisander, Thea
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Oreskovic, Nikolina
    Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, Miljövetenskap.
    Fröhlig, Florence
    Södertörns högskola, Institutionen för historia och samtidsstudier, Etnologi.
    Stedt, Kristoffer
    Göteborgs universitet, Sverige.
    De unga gör helt rätt när de stämmer staten: 1 620 forskare och lärare i forskarvärlden: Vi ställer oss bakom Auroras klimatkrav2022Inngår i: Aftonbladet, nr 2022-12-07, s. 2Artikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
    Abstract [sv]

    Vi, 1 620 forskare samt lärare vid universitet och högskolor, är eniga med de unga bakom Auroramålet: De drabbas och riskerar att drabbas allvarligt av klimatkrisen under sin livstid. De klimatåtgärder vi vidtar i närtid avgör deras framtid. Sverige måste ta ansvar och göra sin rättvisa andel av det globala klimatarbetet. 

    I strid med Parisavtalet ökar utsläppen av växthusgaser i en takt som gör att 1,5-gradersmålet kan överskridas om några år. De globala effekterna blir allt mer synliga med ständiga temperaturrekord, smältande isar, havshöjning och extremväder som torka, förödande bränder och skyfall med enorma översvämningar, som i Pakistan nyligen. Försörjningen av befolkningen utsätts för allvarliga hot i många länder.

    Minskningen av den biologiska mångfalden är extrem. Klimatkrisen är enligt WHO det största hotet mot människors hälsa i hela världen och barn utgör en särskilt sårbar grupp. Med Sveriges nordliga läge sker uppvärmningen här dubbelt så fort som det globala genomsnittet. Det förskjuter utbredningsområden för växtlighet och sjukdomsbärande insekter och ökar förekomsten av extremväder såsom värmeböljor, skogsbränder och översvämningar samt av många olika sorters infektioner och allergier. När extremväder ökar, ökar även stressen och risken för mental ohälsa. Värmeböljor ökar risken för sjukdom och död hos sårbara grupper som äldre, små barn och personer med kroniska sjukdomar. De negativa effekterna på hälsan kommer att öka i takt med klimatkrisen och barn riskerar att drabbas av ackumulerade negativa hälsoeffekter under hela sina liv. Redan i dag är mer än hälften av unga mellan 12 och 18 år i Sverige ganska eller mycket oroliga för klimat och miljö. Detta är förståeligt när våra beslutsfattare inte gör vad som krävs.

    Den juridiska och moraliska grunden för arbetet mot klimatförändringarna är att varje land måste göra sin rättvisa andel av det globala klimatarbetet. Centralt i det internationella klimatramverket är att rika länder med höga historiska utsläpp, däribland Sverige, måste gå före resten av världen. Dessa länder måste också bidra till att finansiera klimatomställningen i länderna i det Globala Syd, som är minst ansvariga för klimatkrisen men drabbas hårdast. Denna rättviseprincip är tydlig i Parisavtalet och var en het diskussionsfråga under COP27 i Sharm el-Sheikh, men lyser med sin frånvaro i det svenska klimatarbetet. 

    Sverige har satt mål för att minska sina utsläpp. Men de är helt otillräckliga: minskningstakten är för låg och målen tillåter samtidigt att åtgärder skjuts på framtiden. Dessutom exkluderas merparten av Sveriges utsläpp från de svenska nationella utsläppsmålen; bland annat utelämnas utsläpp som svensk konsumtion orsakar utanför Sveriges gränser, utsläpp från utrikes transporter och utsläpp från markanvändning och skogsbruk, exempelvis utsläpp från förbränning av biobränslen eller utsläpp från dikade våtmarker (Prop. 2016/17:146 s.25-28).

    Sverige saknar dessutom ett eget mål för att öka upptaget av växthusgaser genom utökat skydd och restaurering av ekosystem, något som krävs för att begränsa de värsta konsekvenserna av klimatkrisen (IPCC s.32). Trots dessa låga ambitioner misslyckas Sverige med att nå sina utsläppsmål, konstaterar både Klimatpolitiska rådet och Naturvårdsverket. En klimatpolitik i linje med Parisavtalet kräver både att alla typer av växthusgasutsläpp minskar samtidigt som – inte i stället för – upptaget av växthusgaser maximeras: i dag misslyckas Sverige på bägge fronter.

    Slutsatsen är tydlig. Sverige vidtar inte de åtgärder som krävs för att skydda barns och ungdomars rättigheter enligt Europakonventionen till skydd för de mänskliga rättigheterna. Detta medför allvarliga risker för liv och hälsa för unga generationer, människor i andra länder och särskilt utsatta grupper. Detta kan inte fortsätta. Därför ställer vi oss bakom Auroras krav att Sverige börjar göra sin rättvisa andel och omedelbart sätter igång ett omfattande och långtgående klimatarbete som vilar på vetenskaplig grund och sätter rättvisa i centrum.

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