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Norbäck Ivarsson, LenaORCID iD iconorcid.org/0000-0001-9799-570x
Publications (9 of 9) Show all publications
Andrén, E., van Wirdum, F., Norbäck Ivarsson, L., Lönn, M., Moros, M. & Andrén, T. (2020). Medieval versus recent environmental conditions in the Baltic Proper, what was different a thousand years ago?. Palaeogeography, Palaeoclimatology, Palaeoecology, 555, Article ID 109878.
Open this publication in new window or tab >>Medieval versus recent environmental conditions in the Baltic Proper, what was different a thousand years ago?
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2020 (English)In: Palaeogeography, Palaeoclimatology, Palaeoecology, ISSN 0031-0182, E-ISSN 1872-616X, Vol. 555, article id 109878Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Baltic Sea, Diatoms, Phytoplankton seasonality, Medieval Climate Anomaly, Hypoxia
National Category
Environmental Sciences
Research subject
Environmental Studies; Baltic and East European studies
Identifiers
urn:nbn:se:sh:diva-41235 (URN)10.1016/j.palaeo.2020.109878 (DOI)000552137900020 ()2-s2.0-85086659693 (Scopus ID)
Funder
The Foundation for Baltic and East European Studies, 34/2013The Foundation for Baltic and East European Studies, 75/2014
Available from: 2020-06-24 Created: 2020-06-24 Last updated: 2020-08-13Bibliographically approved
Norbäck Ivarsson, L. (2020). Tracing environmental change and human impact as recorded in sediments from coastal areas of the northwestern Baltic Proper. (Doctoral dissertation). Huddinge: Södertörns högskola
Open this publication in new window or tab >>Tracing environmental change and human impact as recorded in sediments from coastal areas of the northwestern Baltic Proper
2020 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The eutrophication of the Baltic Sea due to increased anthropogenic nutrient loads during the 20th century is well documented and studied. However, in the Baltic Sea drainage area, humans have affected the environment longer than the environmental monitoring can provide data for. Sediment records from lakes and seas can provide fundamental data on the environmental conditions before ecosystems were impacted by humans and give the range of natural variation.

This thesis presents diatom and geochemistry stratigraphies from five sediment records along the southeast coast of Sweden, northwestern Baltic Proper. These records cover time periods of 500 years to more than 2,000 years. The diatom stratigraphies and geochemical proxies allow for reconstruction of environmental histories at these sites. Overall, the results show that the environmental changes that have occurred in the coastal zone in recent centuries are unprecedented over the last two millennia. The records from the coastal zone show only minor variations in the diatom stratigraphies and nitrogen stable isotope signals through history until recent centuries. The results show no evidence of increased runoff of nutrients from land during medieval times.

Temperature anomalies since 500 CE have had little or no significant effect on the diatom assemblages from the coastal sites, while increased nutrient input from land has had a significant effect. Anthropogenic nutrient runoff has affected the diatom assemblages most markedly during the 20th century. The results show a time lag of the onset of eutrophication of approximately 100 years between the coast and open Baltic Sea, highlighting how the coastal zone acts as a buffer for the open Baltic Sea. The timing for the onset of eutrophication in these coastal areas is site-specific. For several sites, reference conditions prevailed more than 200 years ago. Water transparency at this time allowed for extensive distribution of benthic diatom habitats, such as macrophytes. The years of maximum nutrient load to the Baltic Sea during the 1970s–1980s is recorded in the diatom stratigraphies, especially with regard to the concentration of diatom valves in the sediments. There has been a recovery in diatom absolute abundance since maximum pollution years. However, there is no indication of a recovery in diatom species composition in the investigated coastal sites, and these sites are thus far from reaching a “good environmental status” according to the EU Water Framework Directive. The outcomes of this thesis highlight the importance of a longer time perspective than the environmental monitoring can provide.

Abstract [sv]

Övergödningen av Östersjön under 1900-talet är väldokumenterad och har bland annat resulterat i sämre siktdjup, att cyanobakterieblomningar har blivit mer omfattande och vanligare, utbredd syrebrist i bottenvatten, och en förändrad artsammansättning av många organismgrupper. Systematiskt provtagna mätdata från miljöövervakningen finns bara tillgänglig från 1960–70-talet och därmed vet vi väldigt lite om Östersjöns ekosystem före människans storskaliga påverkan. Sedimentkärnor från sjöar och hav fungerar som ett historiskt arkiv som under årtusenden lagrat information om dåtidens ekosystem. I denna avhandling används bevarade subfossila kiselalger och geokemi för att spåra miljöförändringar längs svenska sydostkusten de senaste tvåtusen åren. Resultat presenteras från fem sedimentkärnor från Östersjökusten, från Stockholms skärgård i norr till Gåsfjärden i söder, längs en sträcka på ca 250 km.

Alla stratigrafier tyder på stabila förhållanden i dessa kustområden under yngre järnålder (500 före vår tideräkning – 1050 efter vår tideräkning (evt)) och medeltid (1050–1500 evt), fram till 1700-talet. Varken förändringar i klimat eller markanvändning har påverkat dessa kustområden i någon större utsträckning tills för några hundra år sedan. Det finns inga tecken på effekter av mänsklig aktivitet som exempelvis jordbruk fram till mer nutida förändringar. Alla undersökningsplatser har påverkats av övergödning under de senaste århundradena. Den exakta starten för ökad näringstillförsel skiljer sig något mellan platserna. De första tecknen på övergödning är från slutet av 1700-talet, och i början av 1800-talet är artsammansättningen av kiselalger redan förändrad. Storskaliga förändringar i markanvändning skedde under 1800-talet och fortsatte in på 1900-talet. Våtmarker och sjöar dikades ut, jordbruk med ängar och traditionell träda av jordbruksmark fasades ut till förmån för vallodling, till det kom konstgödsel i slutet av 1800-talet. Växande städer, industrier och reningsverk är punktkällor som i varierande grad har påverkat dessa kustområden. De första tecknen på övergödning syns ca 100 år tidigare vid kusten än i öppna Östersjön, vilket belyser kustzonens roll som näringsfilter. I öppna Östersjön har både klimatet och näringstillförsel från land påverkat artsammansättningen av kiselalger de senaste 2 000 åren. I kustområdet däremot har de direkta effekterna av klimatet spelat en mindre roll, och artsammansättningen av kiselalger har främst varit påverkad av näringstillförsel från land. Övergödningen har resulterat i ökad pelagisk primärproduktion och därmed lägre siktdjup, vilket har begränsat utbredningen av bottenlevande arter.

I Östersjön finns inga opåverkade områden kvar, och därmed inga referensområden för att definiera referensvärden enligt EUs vattendirektiv. Resultaten som presenteras i denna avhandling visar att i flera av de undersökta kustområdena rådde ett miljötillstånd opåverkat av mänsklig aktivitet för mer än 200 år sedan. Maximal tillförsel av näring till Östersjön skedde under 1960–70-talet, vilket avspeglar sig i koncentrationen av kiselalger i sedimenten, något som kan användas som en proxy för primärproduktion. Lägre koncentrationer av kiselalger i sedimenten de senaste årtiondena indikerar en bättre vattenkvalité. Däremot syns ännu ingen förbättring i artsammansättning av kiselalger som indikerar en tillbakagång till referensvärden. Inte heller syns tecken på någon förbättring vad gäller siktdjup i undersökningsområdena.

Place, publisher, year, edition, pages
Huddinge: Södertörns högskola, 2020. p. 181
Series
Södertörn Doctoral Dissertations, ISSN 1652-7399 ; 178
Keywords
Baltic Sea, paleoecology, diatom stratigraphy, stable nitrogen isotopes, hypoxia, nutrient discharge, eutrophication, Medieval Climate Anomaly, Little Ice Age
National Category
Environmental Sciences
Research subject
Environmental Studies; Baltic and East European studies
Identifiers
urn:nbn:se:sh:diva-42061 (URN)978-91-89109-29-2 (ISBN)978-91-89109-30-8 (ISBN)
Public defence
2020-11-06, MA624/via link, Alfred Nobels allé 7, Huddinge, 13:00 (English)
Opponent
Supervisors
Funder
The Foundation for Baltic and East European Studies, 34/2013
Available from: 2020-10-15 Created: 2020-10-08 Last updated: 2021-01-07Bibliographically approved
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, E-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)000471701600001 ()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, 34/2013Stockholm County CouncilThe Foundation for Baltic and East European Studies, 75/2014
Available from: 2019-06-25 Created: 2019-06-25 Last updated: 2022-03-02Bibliographically 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: 2022-05-03Bibliographically approved
Bolinder, K., Norbäck Ivarsson, L., Humphreys, A. M., Ickert-Bond, S. M., Han, F., Hoorn, C. & Rydin, C. (2016). Pollen morphology of Ephedra (Gnetales) and its evolutionary implications. Grana, 55(1), 24-51
Open this publication in new window or tab >>Pollen morphology of Ephedra (Gnetales) and its evolutionary implications
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2016 (English)In: Grana, ISSN 0017-3134, E-ISSN 1651-2049, Vol. 55, no 1, p. 24-51Article in journal (Refereed) Published
Abstract [en]

The Ephedra lineage can be traced at least to the Early Cretaceous. Its characteristically polyplicate pollen is well-represented in the fossil record and is frequently used as an indicator of paleoclimate. However, despite previous efforts, knowledge about variation and evolution of ephedroid pollen traits is poor. Here, we document pollen morphology of nearly all extant species of Ephedra, using a combination of scanning electron microscopy (SEM) and light microscopy (LM), and reconstruct ancestral states of key pollen traits. Our results indicate that the ancestral Ephedra pollen type has numerous plicae interspaced by unbranched pseudosulci, while the derived pollen type has branched pseudosulci and (generally) fewer plicae. The derived type is inferred to have evolved independently twice, once along the North American stem branch and once along the Asian stem branch. Pollen of the ancestral type is common in Mesozoic fossil records, especially from the Early Cretaceous, but it is less commonly reported from the Cenozoic. The earliest documentation of the derived pollen type is from the latest Cretaceous, after which it increases strongly in abundance during the Paleogene. The results of the present study have implications for the age of crown group Ephedra as well as for understanding evolution of pollination syndromes in the genus.

Keywords
character evolution, light microscopy, phylogeny, polyplicate, pseudosulci, scanning electron microscopy, Welwitschia
National Category
Environmental Sciences
Identifiers
urn:nbn:se:sh:diva-28189 (URN)10.1080/00173134.2015.1066424 (DOI)000371864800004 ()2-s2.0-84955491470 (Scopus ID)
Available from: 2015-09-03 Created: 2015-09-03 Last updated: 2020-05-08Bibliographically approved
Ivarsson, M., Peckmann, J., Tehler, A., Broman, C., Bach, W., Behrens, K., . . . Norbäck Ivarsson, L. (2015). Zygomycetes in Vesicular Basanites from Vesteris Seamount, Greenland Basin - A New Type of Cryptoendolithic Fungi. PLOS ONE, 10(7), Article ID e0133368.
Open this publication in new window or tab >>Zygomycetes in Vesicular Basanites from Vesteris Seamount, Greenland Basin - A New Type of Cryptoendolithic Fungi
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2015 (English)In: PLOS ONE, E-ISSN 1932-6203, Vol. 10, no 7, article id e0133368Article in journal (Refereed) Published
Abstract [en]

Fungi have been recognized as a frequent colonizer of subseafloor basalt but a substantial understanding of their abundance, diversity and ecological role in this environment is still lacking. Here we report fossilized cryptoendolithic fungal communities represented by mainly Zygomycetes and minor Ascomycetes in vesicles of dredged volcanic rocks (basanites) from the Vesteris Seamount in the Greenland Basin. Zygomycetes had not been reported from subseafloor basalt previously. Different stages in zygospore formation are documented in the studied samples, representing a reproduction cycle. Spore structures of both Zygomycetes and Ascomycetes are mineralized by romanechite-like Mn oxide phases, indicating an involvement in Mn(II) oxidation to form Mn(III, VI) oxides. Zygospores still exhibit a core of carbonaceous matter due to their resistance to degradation. The fungi are closely associated with fossiliferous marine sediments that have been introduced into the vesicles. At the contact to sediment infillings, fungi produced haustoria that penetrated and scavenged on the remains of fragmented marine organisms. It is most likely that such marine debris is the main carbon source for fungi in shallow volcanic rocks, which favored the establishment of vital colonies.

National Category
Environmental Sciences
Identifiers
urn:nbn:se:sh:diva-28164 (URN)10.1371/journal.pone.0133368 (DOI)000358198200062 ()26181773 (PubMedID)2-s2.0-84941368555 (Scopus ID)
Funder
Swedish Research Council, 2012-4364
Available from: 2015-09-01 Created: 2015-09-01 Last updated: 2021-06-14Bibliographically approved
Norbäck Ivarsson, L., Ivarsson, M., Lundberg, J., Sallstedt, T. & Rydin, C. (2013). Epilithic and aerophilic diatoms in the artificial environment of Kungsträdgården metro station, Stockholm, Sweden. International Journal of Speleology, 42(3), 289-297
Open this publication in new window or tab >>Epilithic and aerophilic diatoms in the artificial environment of Kungsträdgården metro station, Stockholm, Sweden
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2013 (English)In: International Journal of Speleology, ISSN 0392-6672, E-ISSN 1827-806X, Vol. 42, no 3, p. 289-297Article in journal (Refereed) Published
Abstract [en]

The Kungsträdgården metro station is an artificial and urban subsurface environment illuminated with artificial light. Its ecosystem is almost completely unknown and as a first step to better understand the biology and rock wall habitats the diatom flora was investigated. A total of 12 species were found growing on the rock walls of Kungsträdgården metro station. The results show the diatom flora in Kungsträdgården to be dominated by e.g. Diadesmis contentaDiadesmis perpusillaPinnularia appendiculataNitzschia amphibiaNitzschia sinuata and Diploneis ovalis. One species, Caloneis cf. aerophila, has never been reported from Sweden before. Significant differences in the species composition between the sampling sites indicate Kungsträdgården metro station to be a heterogeneous habitat that provides different microhabitats.

National Category
Botany
Identifiers
urn:nbn:se:sh:diva-25295 (URN)10.5038/1827-806X.42.3.12 (DOI)000325934700013 ()2-s2.0-84887962975 (Scopus ID)
Available from: 2014-11-26 Created: 2014-11-26 Last updated: 2020-05-08Bibliographically approved
Norbäck Ivarsson, L., Lönn, M., Andrén, T. & Andrén, E.Exploring paleoecological trends since 500 CE: a comparison between coastal and open Baltic Proper.
Open this publication in new window or tab >>Exploring paleoecological trends since 500 CE: a comparison between coastal and open Baltic Proper
(English)Manuscript (preprint) (Other academic)
National Category
Environmental Sciences
Identifiers
urn:nbn:se:sh:diva-42043 (URN)
Funder
The Foundation for Baltic and East European Studies, 75/2014
Note

Som manuskript i avhandling. As manuscript in dissertation.

Available from: 2020-10-05 Created: 2020-10-05 Last updated: 2023-07-12Bibliographically approved
Norbäck Ivarsson, L., Andrén, T., Moros, M., Andersen, T. & Andrén, E.Signs of early eutrophication in the Stockholm outer archipelago as evident in a 500-year-long sediment record.
Open this publication in new window or tab >>Signs of early eutrophication in the Stockholm outer archipelago as evident in a 500-year-long sediment record
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(English)Manuscript (preprint) (Other academic)
National Category
Environmental Sciences
Identifiers
urn:nbn:se:sh:diva-42042 (URN)
Note

Som manuskript i avhandling. As manuscript in dissertation.

Available from: 2020-10-05 Created: 2020-10-05 Last updated: 2020-10-08Bibliographically approved
Projects
UPPBASER - Understanding Past and Present Baltic Sea Ecosystem Response - background for a sustainable future [34/2013_OSS]; Södertörn University; Publications
Andrén, E., van Wirdum, F., Norbäck Ivarsson, L., Lönn, M., Moros, M. & Andrén, T. (2020). Medieval versus recent environmental conditions in the Baltic Proper, what was different a thousand years ago?. Palaeogeography, Palaeoclimatology, Palaeoecology, 555, Article ID 109878. Norbäck Ivarsson, L. (2020). Tracing environmental change and human impact as recorded in sediments from coastal areas of the northwestern Baltic Proper. (Doctoral dissertation). Huddinge: Södertörns högskolaNorbäck 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
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ORCID iD: ORCID iD iconorcid.org/0000-0001-9799-570x

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