| 1. |
- Andrén, Thomas, 1954-, et al.
(författare)
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Östersjön förändras ständigt
- 2005
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Ingår i: Upsala nya tidning. - 1104-0173. ; :8/6:8 juni
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 2. |
- Andrén, Elinor, et al.
(författare)
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Medieval versus recent environmental conditions in the Baltic Proper, what was different a thousand years ago?
- 2020
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Ingår i: Palaeogeography, Palaeoclimatology, Palaeoecology. - : Elsevier. - 0031-0182 .- 1872-616X. ; 555
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 3. |
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| 4. |
- Andrén, Thomas, 1954-, et al.
(författare)
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IODP expedition 347 : Baltic Sea basin paleoenvironment and biosphere
- 2015
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Ingår i: Scientific Drilling. - : Copernicus GmbH. - 1816-8957 .- 1816-3459. ; 20, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 5. |
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| 6. |
- Dahl, Martin, 1984-, et al.
(författare)
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A 2,000-Year Record of Eelgrass (Zostera marina L.) : Colonization Shows Substantial Gains in Blue Carbon Storage and Nutrient Retention
- 2024
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Ingår i: Global Biogeochemical Cycles. - : John Wiley & Sons. - 0886-6236 .- 1944-9224. ; 38:3
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 7. |
- Katrantsiotis, Christos, et al.
(författare)
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Holocene relative sea level changes in the Västervik‐Gamlebyviken region on the southeast coast of Sweden, southern Baltic Sea
- 2023
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Ingår i: Boreas. - : John Wiley & Sons. - 0300-9483 .- 1502-3885. ; 52:2, s. 206-222
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Tidskriftsartikel (refereegranskat)abstract
- We reconstruct the Holocene shore displacement of the Västervik-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 ∼7 m a.s.l. is recorded between 8.0 and 7.5 cal. ka BP with a highstand at ∼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 ∼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.
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| 8. |
- Kotthoff, U., et al.
(författare)
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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)
- 2017
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Ingår i: Biogeosciences. - : Copernicus GmbH. - 1726-4170 .- 1726-4189. ; 14, s. 5607-5632
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 9. |
- Moberg, Christina, et al.
(författare)
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De unga gör helt rätt när de stämmer staten : 1 620 forskare och lärare i forskarvärlden: Vi ställer oss bakom Auroras klimatkrav
- 2022
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Ingår i: Aftonbladet. - : Aftonbladet. ; :2022-12-07
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- 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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| 10. |
- Norbäck Ivarsson, Lena, 1987-, et al.
(författare)
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Baltic Sea Coastal Eutrophication in a Thousand Year Perspective
- 2019
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Ingår i: Frontiers in Environmental Science. - : Frontiers Media S.A.. - 2296-665X. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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