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Publications (10 of 35) Show all publications
Norbäck Ivarsson, L., Andrén, T., Moros, M., Andersen, T. J., Lönn, M. & Andrén, E. (2019). Baltic Sea Coastal Eutrophication in a Thousand Year Perspective. Frontiers in Environmental Science, 7, Article ID 88.
Open this publication in new window or tab >>Baltic Sea Coastal Eutrophication in a Thousand Year Perspective
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2019 (English)In: Frontiers in Environmental Science, ISSN 2296-665X, Vol. 7, article id 88Article in journal (Refereed) Published
Abstract [en]

Sediment cores from three sites along the east-coast of Sweden, north-western Baltic Proper, have been studied with respect to lithologies, geochemistry and diatom assemblages to trace and date early human impact with emphasis on nutrient discharge. The three sites Bråviken, Himmerfjärden and Ådfjärden, have been impacted to various degree during the last millennia by multiple stressors like excessive nutrient discharge and hazardous substances, leading to coastal hypoxia, eutrophication and pollution. These stressors are mainly caused by drivers in the drainage area as increased human population, changed land use and point sources as industries and a sewage treatment plant. Even though their detailed history differs, the results show similar general patterns for all three sites. We find no evidence in our data from the coastal zone supporting the hypothesis that the extensive areal distribution of hypoxia in the open Baltic Sea during the Medieval Climate Anomaly was caused by human impact. Timing of the onset of man-made eutrophication, as identified from d15N and changes in diatom composition, differs between the three sites, reflecting the site specific geography and local environmental histories of these areas. The onset of eutrophication dates to 1800 CE in Bråviken and Himmerfjärden areas, and to 1900 CE in the less urban area of Ådfjärden. We conclude that the recorded environmental changes during the last centuries are unique in a thousand year perspective.

Place, publisher, year, edition, pages
Frontiers Media S.A., 2019
Keywords
diatom stratigraphy, stable nitrogen isotopes, hypoxia, Medieval Climate Anomaly, NW Baltic proper, nutrient discharge
National Category
Environmental Sciences
Research subject
Environmental Studies; Baltic and East European studies
Identifiers
urn:nbn:se:sh:diva-38479 (URN)10.3389/fenvs.2019.00088 (DOI)2-s2.0-85068480167 (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, 1562/3.1.1/2013Stockholm County Council
Available from: 2019-06-25 Created: 2019-06-25 Last updated: 2019-08-06Bibliographically 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
Ning, W., Nielsen, A., Norbäck Ivarsson, L., Jilber, T., Åkesson, C., Slomp, C., . . . Filipsson, H. (2018). Anthropogenic and climatic impacts on a coastal environment in the Baltic Sea over the last 1000 years. Anthropocene, 21, 66-79
Open this publication in new window or tab >>Anthropogenic and climatic impacts on a coastal environment in the Baltic Sea over the last 1000 years
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2018 (English)In: Anthropocene, E-ISSN 2213-3054, Vol. 21, p. 66-79Article in journal (Refereed) Published
Abstract [en]

Coastal environments have experienced large ecological changes as a result of human activities over the last 100−200 years. To understand the severity and potential consequences of such changes, paleoenvironmental records provide important contextual information. The Baltic Sea coastal zone is naturally a vulnerable system and subject to significant human-induced impacts. To put the recent environmental degradation in the Baltic coastal zone into a long-term perspective, and to assess the natural and anthropogenic drivers of environmental change, we present sedimentary records covering the last 1000 years obtained from a coastal inlet (Gåsfjärden) and a nearby lake (Lake Storsjön) in Sweden. We investigate the links between a pollen-based land cover reconstruction from Lake Storsjön and paleoenvironmental variables from Gåsfjärden itself, including diatom assemblages,organic carbon (C) and nitrogen (N) contents, stable C and N isotopic ratios, and biogenic silica contents. The Lake Storsjön record shows that regional land use was characterized by small-scale agricultural activity between 900 and 1400 CE, which slightly intensified between 1400 and 1800 CE. Substantial expansion of cropland was observed between 1800 and 1950 CE, before afforestation between 1950 and 2010 CE. From the Gåsfjärden record, prior to 1800 CE, relatively minor changes in the diatom and geochemical proxies were found. The onset of cultural eutrophication in Gåsfjärden can be traced to the 1800s and intensified land use is identified as the main driver. Anthropogenic activities in the 20th century have caused unprecedented ecosystem changes in the coastal inlet, as reflected in the diatom composition and geochemical proxies.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
land use, eutrophication, mining, hypoxia, coastal area, Baltic Sea
National Category
Earth and Related Environmental Sciences
Research subject
Environmental Studies
Identifiers
urn:nbn:se:sh:diva-34716 (URN)10.1016/j.ancene.2018.02.003 (DOI)000429091500006 ()2-s2.0-85043469367 (Scopus ID)1562/3.1.1/2013 (Local ID)1562/3.1.1/2013 (Archive number)1562/3.1.1/2013 (OAI)
Funder
Swedish Research Council Formas, 217-2010-126The Foundation for Baltic and East European Studies, 1562/3.1.1/2013The Crafoord FoundationEU, European Research Council, 278364
Note

Funder

Royal Physiographic Society in Lund

Netherlands Organization for Scientific Research (NWO Vidi 86405.004)

Available from: 2018-03-05 Created: 2018-03-05 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
Weckström, K., Lewis, J. P., Andrén, E., Ellegaard, M., Rasmussen, P. & Telford, R. (2017). Palaeoenvironmental History of the Baltic Sea: One of the Largest Brackish-Water Ecosystems in the World. In: Weckström, Kaarina; Saunders, Krystyna M.; Gell, Peter A.; Skilbeck, C. Gregory (Ed.), Applications of Paleoenvironmental Techniques in Estuarine Studies: (pp. 615-662). Springer Netherlands
Open this publication in new window or tab >>Palaeoenvironmental History of the Baltic Sea: One of the Largest Brackish-Water Ecosystems in the World
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2017 (English)In: Applications of Paleoenvironmental Techniques in Estuarine Studies / [ed] Weckström, Kaarina; Saunders, Krystyna M.; Gell, Peter A.; Skilbeck, C. Gregory, Springer Netherlands, 2017, p. 615-662Chapter in book (Other academic)
Abstract [en]

The past of the Baltic Sea has been intensively investigated using a wealth of techniques. By far the largest number of studies has focused on sea level and salinity changes, driven by global climate and isostatic crustal rebound after the Baltic Sea emerged underneath the Weichselian Ice Sheet ca. 15,000 cal. years BP. The post-glacial history of the Baltic has included both freshwater and brackish water stages depending on the connection of the Baltic Sea with the world’s oceans. As the Baltic is one of the most polluted sea areas in the world, many studies have also focused on both the long-term trends in nutrients and productivity and the relatively recent anthropogenic eutrophication. The long-term changes in the trophic state of the Baltic Sea have been found to be linked to changes in climate, which controls freshwater discharge from the catchment and weathering rates, as well as marine water inflow from the North Sea. The productivity of the Baltic Sea has followed major climate patterns: it was high during warm periods and lower during phases of deteriorating climate. Recent eutrophication of the Baltic Sea can mainly be explained by a marked increase in discharge of nutrients caused by a growing population and changes in the agricultural practice, although long-term climate variability also plays a part. Signs of recovery have recently been detected, however, the Baltic Sea is still far from its pre-industrial trophic state.

Place, publisher, year, edition, pages
Springer Netherlands, 2017
Series
Developments in Paleoenvironmental Research, ISSN 1571-5299 ; 20
Keywords
Palaeoenvironmental reconstructions, Salinity changes, Sea level, Nutrient status, Water, Framework, Directive, Baltic Sea
National Category
Environmental Sciences
Research subject
Baltic and East European studies
Identifiers
urn:nbn:se:sh:diva-32366 (URN)10.1007/978-94-024-0990-1_24 (DOI)978-94-024-0988-8 (ISBN)978-94-024-0990-1 (ISBN)
Available from: 2017-04-10 Created: 2017-04-10 Last updated: 2017-04-10Bibliographically 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
Snoeijs-Leijonmalm, P. & Andrén, E. (2017). Why is the Baltic Sea so special to live in?. In: Snoeijs-Leijonmalm, Pauline; Schubert, Hendrik; Radziejewska, Teresa (Ed.), Biological Oceanography of the Baltic Sea: (pp. 23-84). Springer Netherlands
Open this publication in new window or tab >>Why is the Baltic Sea so special to live in?
2017 (English)In: Biological Oceanography of the Baltic Sea / [ed] Snoeijs-Leijonmalm, Pauline; Schubert, Hendrik; Radziejewska, Teresa, Springer Netherlands, 2017, p. 23-84Chapter in book (Other academic)
Abstract [en]

"Why is the Baltic Sea so special to live in", is the main question the authors here give several arguments or answers for. Geographical position, geological development, hydrographical features, climate and physical drivers together create the Baltic Sea environment. The Baltic Sea water is brackish and characterized by pronounced salinity gradients, both in horizontal and vertical directions, because of the large volume of freshwater runoff from over 100 rivers, which mixes with the saline water from the Kattegat that enters the Baltic Sea via narrow shallow straits. Being a semi-enclosed continental sea with a large drainage area compared to its water volume , the Baltic Sea ecosystem is heavily impacted by the surrounding landmasses. The water residence time in the Baltic Sea is long (30–40 years), and therefore discharged nutrients and toxic compounds circulate within the sea for a long time, which contributes to its vulnerability to eutrophication and chemical contamination by hazardous substances. The Baltic Sea Area is geologically young and the Baltic Sea ecosystem is extremely young in an evolutionary perspective. Only few macroscopic species are fully adapted to its low-salinity environment. In an ecosystem-wide perspective, the large-scale Baltic Sea gradient is the principal ecological characteristic of the Baltic Sea.

Place, publisher, year, edition, pages
Springer Netherlands, 2017
Keywords
Ecological characteristics, Environmental gradients, Geography, Geology, Human impacts Hydrography
National Category
Environmental Sciences
Research subject
Environmental Studies; Baltic and East European studies
Identifiers
urn:nbn:se:sh:diva-32465 (URN)10.1007/978-94-007-0668-2_2 (DOI)2-s2.0-85033707276 (Scopus ID)978-94-007-0667-5 (ISBN)978-94-007-0668-2 (ISBN)
Available from: 2017-05-04 Created: 2017-05-04 Last updated: 2017-11-30Bibliographically approved
Lewis, J., Ryves, D., Rasmussen, P., Olsen, J., Knudsen, K.-L., Andersen, S., . . . Juggins, S. (2016). The shellfish enigma across the Mesolithic-Neolithic transition in southern Scandinavia. Quaternary Science Reviews, 151, 315-320, Article ID http://dx.doi.org/10.1016/j.quascirev.2016.09.004.
Open this publication in new window or tab >>The shellfish enigma across the Mesolithic-Neolithic transition in southern Scandinavia
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2016 (English)In: Quaternary Science Reviews, ISSN 0277-3791, E-ISSN 1873-457X, Vol. 151, p. 315-320, article id http://dx.doi.org/10.1016/j.quascirev.2016.09.004Article in journal (Refereed) Published
Abstract [en]

The well-known and widespread replacement of oysters (abundant during the Mesolithic period) by cockles and mussels in many Danish Stone Age shell middens ca. 5900 cal yrs BP coincides with the transition to agriculture in southern Scandinavia. This human resource shift is commonly believed to reflect changing resource availability, driven by environmental and/or climatic change at the Mesolithic-Neolithic transition rather than cultural choice. While several hypotheses have been proposed to explain the “Mesolithic-Neolithic oyster decline”, an explanation based on a sudden freshening of the inner Danish waters has received most attention. Here, for the first time, we test and refute this long-standing hypothesis that declining salinity explains the marked reduction in oysters identified within numerous shell middens across coastal Denmark at the Mesolithic-Neolithic transition using quantitative and qualitative salinity inference from several, independent proxies (diatoms, molluscs and foraminifera) from multiple Danish fjord sites. Alternatively, we attribute the oyster decline to other environmental causes (particularly changing sedimentation), ultimately driven by external climatic forcing. Critical application of such high-quality environmental archives can reinvigorate archaeological debates and can aid in understanding and managing environmental change in increasingly impacted coastal regions.

Place, publisher, year, edition, pages
Elsevier, 2016
Keywords
Oysters;Mesolithic-Neolithic transition; Diatoms; Foraminifera; Molluscs; Denmark; Coastal; Salinity; Shell midden
National Category
Earth and Related Environmental Sciences
Research subject
Environmental Studies
Identifiers
urn:nbn:se:sh:diva-31009 (URN)10.1016/j.quascirev.2016.09.004 (DOI)000386404300020 ()2-s2.0-84992389389 (Scopus ID)
Available from: 2016-10-17 Created: 2016-10-17 Last updated: 2018-07-05Bibliographically approved
Andrén, T., Jørgensen, B. B., Cotterill, C., Green, S. & Andrén, E. (2015). Baltic Sea Basin Paleoenvironment: Expedition 347 of the mission-specific drilling platform  from and to Kiel, Germany Sites M0059–M0067  12 September–1 November 2013. Integrated Ocean Drilling Program
Open this publication in new window or tab >>Baltic Sea Basin Paleoenvironment: Expedition 347 of the mission-specific drilling platform  from and to Kiel, Germany Sites M0059–M0067  12 September–1 November 2013
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2015 (English)Report (Other academic)
Place, publisher, year, edition, pages
Integrated Ocean Drilling Program, 2015
Series
Proceedings of the Integrated Ocean Drilling Programme, ISSN 1930-1014 ; 347
National Category
Environmental Sciences
Identifiers
urn:nbn:se:sh:diva-28067 (URN)10.2204/iodp.proc.347.2015 (DOI)
Available from: 2015-08-14 Created: 2015-08-14 Last updated: 2019-06-25Bibliographically approved
Andrén, E., Klimaschewski, A., Self, A. E., St. Amour, N., Andreev, A. A., Bennett, K. D., . . . Hammarlund, D. (2015). Holocene climate and environmental change in north-eastern Kamchatka (Russian Far East), inferred from a multi-proxy study of lake sediments. Global and Planetary Change, 134, 41-54
Open this publication in new window or tab >>Holocene climate and environmental change in north-eastern Kamchatka (Russian Far East), inferred from a multi-proxy study of lake sediments
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2015 (English)In: Global and Planetary Change, ISSN 0921-8181, E-ISSN 1872-6364, Vol. 134, p. 41-54Article in journal (Refereed) Published
Abstract [en]

A sediment record from a small lake in the north-eastern part of the Kamchatka Peninsula has been investigated in a multi-proxy study to gain knowledge of Holocene climatic and environmental change. Pollen, diatoms, chironomids and selected geochemical parameters were analysed and the sediment record was dated with radiocarbon. The study shows Holocene changes in the terrestrial vegetation as well as responses of the lake ecosystem to catchment maturity and multiple stressors, such as climate change and volcanic eruptions. Climate change is the major driving force resulting in the recorded environmental changes in the lake, although recurrent tephra deposition events also contributed. The sediment record has an age at the base of about 10,000 cal yrs BP, and during the first 400 years the climate was cold and the lake exhibited extensive ice-cover during winter and relatively low primary production. Soils in the catchment were poor with shrub alder and birches dominatingthe vegetation surrounding the lake. At about 9600–8900 cal yrs BP the climate was cold and moist, and strong seasonal wind stress resulted in reduced ice-cover and increased primary production. After ca. 8900 cal yrs BP the forest density increased around the lake, runoff decreased in a generally drier climate resulting in decreasedprimary production in the lake until ca. 7000 cal yrs BP. This generally dry climate was interrupted by a brief climatic perturbation, possibly attributed to the 8.2 ka event, indicating increasingly windy conditions with thick snow cover, reduced ice-cover and slightly elevated primary production in the lake. The diatom record shows maximum thermal stratification at ca. 6300–5800 cal yrs BP and indicates together with the geochemical proxies a dry and slightly warmer climate resulting in a high productive lake. The most remarkably change in the catchment vegetation occurred at ca. 4200 cal yrs BP in the form of a conspicuous increase in Siberian dwarf pine (Pinus pumila), indicating a shift to a cooler climate with a thicker and more long-lasting snow cover. Thisvegetational change was accompanied by marked shifts in the diatom and chironomid stratigraphies, which are also indicative of colder climate and more extensive ice-cover.

Keywords
pollen, diatoms, chironomids, geochemistry, climate change, tephras
National Category
Earth and Related Environmental Sciences
Research subject
Environmental Studies
Identifiers
urn:nbn:se:sh:diva-27905 (URN)10.1016/j.gloplacha.2015.02.013 (DOI)000365369900005 ()2-s2.0-84946563408 (Scopus ID)
Funder
Swedish Research Council, 621-2004-5224Swedish Research Council, 621-2005-4444
Available from: 2015-07-01 Created: 2015-07-01 Last updated: 2018-04-05Bibliographically approved
Projects
Environmental Risk Governance of the Baltic Sea (RISKGOV). [A032-2008_OSS]; Södertörn UniversityUPPBASER - Understanding Past and Present Baltic Sea Ecosystem Response - background for a sustainable future [34/2013_OSS]; Södertörn University; Publications
Norbäck Ivarsson, L., Andrén, T., Moros, M., Andersen, T. J., Lönn, M. & Andrén, E. (2019). Baltic Sea Coastal Eutrophication in a Thousand Year Perspective. Frontiers in Environmental Science, 7, Article ID 88. 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. Ning, W., Nielsen, A., Norbäck Ivarsson, L., Jilber, T., Åkesson, C., Slomp, C., . . . Filipsson, H. (2018). Anthropogenic and climatic impacts on a coastal environment in the Baltic Sea over the last 1000 years. Anthropocene, 21, 66-79Kotthoff, 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, 5607-5632Andrén, E., Telford, R. J. & Jonsson, P. (2017). Reconstructing the history of eutrophication and quantifying total nitrogen reference conditions in Bothnian Sea coastal waters. Estuarine, Coastal and Shelf Science, 198, 320-328Andrén, E. & Andrén, T. (2014). Syrefria bottnar - orsakade av klimat, människa eller både och?. Havsutsikt (2), 12-14
Late Pleistocene and Holocene climate forcing on the Baltic Sea [75/2014_OSS]; Södertörn University; 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), 761-778van 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. 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), 593-608Kotthoff, 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, 5607-5632Obrochta, 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), 858-871Hardisty, 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
Seaside - A multidisciplinary study of maritime environmental history [55/2017_OSS]; Södertörn University
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