| 1. |
- Rämö, Robert, et al.
(författare)
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Sediment Remediation Using Activated Carbon: Effects of Sorbent Particle Size and Resuspension on Sequestration of Metals and Organic Contaminants.
- 2022
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Ingår i: Environmental toxicology and chemistry. - : Wiley. - 1552-8618 .- 0730-7268. ; 41:4, s. 1096-1110
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Tidskriftsartikel (refereegranskat)abstract
- Thin-layer capping using activated carbon (AC) has been described as a cost-effective in situ sediment remediation method for organic contaminants. In this study, we compare the capping efficiency of powdered AC (PAC) against granular AC (GAC) using contaminated sediment from Oskarshamn harbor, Sweden. The effects of resuspension on contaminant retention and cap integrity were also studied. Intact sediment cores were collected from the outer harbor and brought to the laboratory. Three thin-layer caps, consisting of PAC or GAC mixed with clay, or clay only, were added to the sediment surface. Resuspension was created using a motor-driven paddle to simulate propeller wash from ship traffic. Passive samplers were placed in the sediment and in the water column to measure the sediment-to-water release of PAHs, PCBs, and metals. Our results show that a thin-layer cap with PAC reduced sediment-to-water fluxes of PCBs by 57 % under static conditions and 91 % under resuspension. Thin-layer capping with GAC was less effective than PAC, but reduced fluxes of high-molecular weight PAHs. Thin-layer capping with AC was less effective in retaining metals, except for Cd, which release was significantly reduced by PAC. Resuspension generally decreased water concentrations of dissolved cationic metals, perhaps due to sorption to suspended sediment particles. Sediment resuspension in treatments without capping increased fluxes of PCBs with log Kow > 7 and PAHs with log Kow 5 6, but resuspension reduced PCB and PAH fluxes through the PAC thin-layer cap. Overall, PAC performed better than GAC, but adverse effects on the benthic community and transport of PAC to non-target areas are drawbacks that favor the use of GAC. This article is protected by copyright. All rights reserved.© 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.
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| 2. |
- Åkesson, Sofia, et al.
(författare)
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Characterizing natural degradation of tetrachloroethene (PCE) using a multidisciplinary approach
- 2020
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Ingår i: Ambio: a Journal of the Human Environment. - : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 50, s. 1074-1088
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Tidskriftsartikel (refereegranskat)abstract
- A site in mid-western Sweden contaminated with chlorinated solvents originating from a previous dry cleaning facility, was investigated using conventional groundwater analysis combined with compound-specific isotope data of carbon, microbial DNA analysis, and geoelectrical tomography techniques. We show the value of this multidisciplinary approach, as the different results supported each interpretation, and show where natural degradation occurs at the site. The zone where natural degradation occurred was identified in the transition between two geological units, where the change in hydraulic conductivity may have facilitated biofilm formation and microbial activity. This observation was confirmed by all methods and the examination of the impact of geological conditions on the biotransformation process was facilitated by the unique combination of the applied methods. There is thus significant benefit from deploying an extended array of methods for these investigations, with the potential to reduce costs involved in remediation of contaminated sediment and groundwater.
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| 3. |
- Katrantsiotis, Christos, et al.
(författare)
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Seasonal variability in temperature trends and atmospheric circulation systems during the Eemian (Last Interglacial) based on n-alkanes hydrogen isotopes from Northern Finland
- 2021
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Ingår i: Quaternary Science Reviews. - Amsterdam : Elsevier. - 0277-3791 .- 1873-457X. ; 273, s. 107250-107250
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Tidskriftsartikel (refereegranskat)abstract
- The Last Interglacial warm period, the Eemian (ca. 130-116 thousand years ago), serves as a reference for projected future climate in a warmer world. However, there is a limited understanding of the seasonal characteristics of interglacial climate dynamics, especially in high latitude regions. In this study, we aimto provide new insights into seasonal trends in temperature and moisture source location, linked to shifts in atmospheric circulation patterns, for northern Fennoscandia during the Eemian. Our study is based on the distribution and stable hydrogen isotope composition (dD) of n-alkanes in a lake sediment sequence from the Sokli paleolake in NE Finland, placed in a multi-proxy framework. The dD values of predominantly macrophyte-derived mid-chain n-alkanes are interpreted to reflect lake water dD variability influenced by winter precipitation dD (dDprec), ice cover duration and deuterium (D)-depleted meltwater. The dD values of terrestrial plant-derived long-chain n-alkanes primarily reflect soil water dD variability modulated by summer dDprec and by the evaporative enrichment of soil and leaf water. The dDprec variability in our study area is mostly attributed to the temperature effect and the moisture source location linked to the relative dominance between D-depleted continental and polar air masses and Denriched North Atlantic air masses. The biomarker signal further corroborates earlier diatom-based studies and pollen-inferred January and July temperature reconstructions from the same sediment sequence. Three phases of climatic changes can be identified that generally follow the secular variationsin seasonal insolation: (i) an early warming trend succeeded by a period of strong seasonality (ii) a midoptimum phase with gradually decreased seasonality and cooler summers, and (iii) a late climatic instability with a cooling trend. Superimposed on this trend, two abrupt cooling events occur in the early and late Eemian. The Sokli dD variability is generally in good agreement with other North Atlantic and Siberian records, reflecting major changes in the atmospheric circulation patterns during the Eemian as a response to orbital and oceanic forcings.
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| 4. |
- Sobek, Anna, et al.
(författare)
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Organic matter degradation causes enrichment of organic pollutants in hadal sediments
- 2023
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Ingår i: Nature Communications. - 2041-1723. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Burial of persistent organic pollutants (POPs) such as polychlorinated biphenyls (PCBs) in deep-sea sediments contributes to 60% of their historical emissions. Yet, empirical data on their occurrence in the deep-ocean is scarce. Estimates of the deep-ocean POP sink are therefore uncertain. Hadal trenches, representing the deepest part of the ocean, are hotspots for organic carbon burial and decomposition. POPs favorably partition to organic carbon, making trenches likely significant sinks for contaminants. Here we show that PCBs occur in both hadal (7720–8085 m) and non-hadal (2560–4050 m) sediment in the Atacama Trench. PCB concentrations normalized to sediment dry weight were similar across sites while those normalized to sediment organic carbon increased exponentially as the inert organic carbon fraction of the sediment increased in degraded hadal sediments. We suggest that the unique deposition dynamics and elevated turnover of organic carbon in hadal trenches increase POP concentrations in the deepest places on Earth.
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| 5. |
- Tsiligiannis, Epameinondas, et al.
(författare)
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A Four Carbon Organonitrate as a Significant Product of Secondary Isoprene Chemistry
- 2022
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Ingår i: Geophysical Research Letters. - : American Geophysical Union (AGU). - 0094-8276 .- 1944-8007. ; 49:11
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Tidskriftsartikel (refereegranskat)abstract
- Oxidation of isoprene by nitrate radicals (NO3) or by hydroxyl radicals (OH) under high NOx conditions forms a substantial amount of organonitrates (ONs). ONs impact NOx concentrations and consequently ozone formation while also contributing to secondary organic aerosol. Here we show that the ONs with the chemical formula C4H7NO5 are a significant fraction of isoprene-derived ONs, based on chamber experiments and ambient measurements from different sites around the globe. From chamber experiments we found that C4H7NO5 isomers contribute 5%-17% of all measured ONs formed during nighttime and constitute more than 40% of the measured ONs after further daytime oxidation. In ambient measurements C4H7NO5 isomers usually dominate both nighttime and daytime, implying a long residence time compared to C-5 ONs which are removed more rapidly. We propose potential nighttime sources and secondary formation pathways, and test them using a box model with an updated isoprene oxidation scheme.
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| 6. |
- Gomez-Gener, L., et al.
(författare)
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Global carbon dioxide efflux from rivers enhanced by high nocturnal emissions
- 2021
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Ingår i: Nature Geoscience. - : Springer Science and Business Media LLC. - 1752-0894 .- 1752-0908. ; 14, s. 289-294
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Tidskriftsartikel (refereegranskat)abstract
- Carbon dioxide (CO2) emissions to the atmosphere from running waters are estimated to be four times greater than the total carbon (C) flux to the oceans. However, these fluxes remain poorly constrained because of substantial spatial and temporal variability in dissolved CO2 concentrations. Using a global compilation of high-frequency CO2 measurements, we demonstrate that nocturnal CO2 emissions are on average 27% (0.9 gC m(-2) d(-1)) greater than those estimated from diurnal concentrations alone. Constraints on light availability due to canopy shading or water colour are the principal controls on observed diel (24 hour) variation, suggesting this nocturnal increase arises from daytime fixation of CO2 by photosynthesis. Because current global estimates of CO2 emissions to the atmosphere from running waters (0.65-1.8 PgC yr(-1)) rely primarily on discrete measurements of dissolved CO2 obtained during the day, they substantially underestimate the magnitude of this flux. Accounting for night-time CO2 emissions may elevate global estimates from running waters to the atmosphere by 0.20-0.55 PgC yr(-1). Failing to account for emission differences between day and night will lead to an underestimate of global CO2 emissions from rivers by up to 0.55 PgC yr(-1), according to analyses of high-frequency CO2 measurements.
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| 7. |
- Barthel, Roland, 1967, et al.
(författare)
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Similarity-based approaches in hydrogeology: proposal of a new concept for data-scarce groundwater resource characterization and prediction
- 2021
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Ingår i: Hydrogeology Journal. - : Springer Science and Business Media LLC. - 1435-0157 .- 1431-2174. ; 29:5, s. 1693-1709
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Tidskriftsartikel (refereegranskat)abstract
- A new concept is proposed for describing, analysing and predicting the dynamic behaviour of groundwater resources based on classification and similarity. The concept makes use of the ideas put forward by the “PUB” (predictions in ungauged basins) initiative in surface-water hydrology. One of the approaches developed in PUB uses the principle that similar catchments, exposed to similar weather conditions, will generate a similar discharge response at the catchment outlet. This way, models developed for well-observed catchments can be used to make predictions for ungauged catchments with similar properties (topography, land use, etc.). The concept proposed here applies the same idea to groundwater systems, with the goal to make predictions of the dynamic behaviour of groundwater in poorly observed systems using similarities to well-observed and understood systems. This paper gives an overview of the main ideas, the methodological background, the progress so far, and the challenges that the authors regard as most crucial for further development. One of the main goals of this article is thus to raise interest for this new concept within the groundwater community. There are a multitude of highly interesting aspects to investigate, and a community effort, as with PUB, is required. A second goal is to foster and exchange ideas between the groundwater and surface water research communities who, while often working on similar problems, have often missed the opportunity to learn from each other.
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| 8. |
- Ivarsson, Magnus, et al.
(författare)
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Introducing palaeolithobiology
- 2021
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Ingår i: GFF. - London : Taylor & Francis. - 1103-5897 .- 2000-0863. ; 143:2-3, s. 305-319
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Tidskriftsartikel (refereegranskat)abstract
- A growing literature of deep but also surficial fossilized remains of lithobiological life, often associated with igneous rocks, necessitates the unfolding of a sub-discipline within paleobiology. Here, we introduce the term paleolithobiology as the new auxiliary sub-discipline under which fossilized lithobiology should be handled. We present key criteria that distinguish the paleolithobiological archive from the traditional one and discuss sample strategies as well as scientific perspectives. A majority of paleolithobiological material consists of deep biosphere fossils, and in order to highlight the relevance of these, we present new data on fungal fossils from the Lockne impact crater. Fungal fossils in the Lockne drill cores have been described previously but here we provide new insights into the presence of reproductive structures that indicate the fungi to be indigenous. We also show that these fungi frequently dissolve and penetrate secondary calcite, delineating the role lithobionts plays in geobiological cycles. We hope that the formalization of the sub-discipline paleolithobiology will not only highlight an overlooked area of paleobiology as well as simplify future studies of endo- and epilithic fossil material, but also improve our understanding of the history of the deep biosphere.
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| 9. |
- Ferraro, Mattia, et al.
(författare)
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Multi-century reconstruction of environmental conditions in Lurefjorden, Norway.
- 2024
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Ingår i: 24th Nordic Geological Winter Meeting, 10-12th Jan, 2024, Gothenburg, Sweden.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Benthic foraminiferal assemblages are identified to reconstruct changes in environmental conditions over the last few centuries in Lurefjorden, a western Norwegian fjord. From ca. 1970 until present days the relative abundance of Brizalina skagerrakkensis, an efficient bio-indicator for organic matter fluxes, is enhanced relative to the preceding time interval. Hence, our results suggest that there is an increase of the organic matter within the Lurefjorden basin in the last 50 years. Over the same period, there is also an increase in the absolute abundance of agglutinated species, indicating lower oxygen concentration in the water. A lowering of the oxygen concentrations may have taken place as a response of a greater oxygen consumption caused by a higher organic matter supply in the water column. Accoridng to Aksnes (2009), Lurefjorden was subject to an increased freshening of Norwegian coastal waters (NCW), which has led to a decrease in sunlight penetration into the water column, affecting the oxygen levels and the behavior of marine life within the basin, between 1935 and 2007. Furthermore, we used diversity indices to study the ecological status of the area, showing significant growth in diversity, abundance, and richness within the benthic foraminiferal community over the past 50 years. Our observations highlight that an increase in the input of organic matter over the last century has led to a change in the benthic foraminifera community in the Lurefjorden basin.
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| 10. |
- Edvardsson, Johannes, et al.
(författare)
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Old wood in a new light : an online dendrochronological database
- 2023
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Ingår i: International Journal of Wood Culture. - : Brill Academic Publishers. - 2772-3194 .- 2772-3186. ; 3:1-3, s. 442-463
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Tidskriftsartikel (refereegranskat)abstract
- The Old Wood in a New Light database project focuses on the digitization and accessibility of the results of dendrochronological samples analyzed and archived at four Swedish university-based tree-ring laboratories at Lund University, Stockholm University, University of Gothenburg, and the Swedish University of Agricultural Sciences. Collaboration with the Environmental Archaeology Laboratory and Humlab at Umeå University enables long-term open access to data, raw data, and metadata. In this project, we (1) systematically undertake large-scale entry and open access publication of results from wood samples scientifically analyzed and archived by Swedish laboratories and the associated metadata, into the Strategic Environmental Archaeology Database (SEAD; www.sead.se) research data infrastructure, and (2) actively promote the database as a resource for new and ongoing interdisciplinary research initiatives. Including dendrochronological data in SEAD infrastructure allows interdisciplinary studies that combine major scientific and societal questions. Building on a pilot study of construction timber from southern Sweden and adaptation of SEAD digitization workflows, more than 70 000 samples archived at the four dendrochronological laboratories are now being handled in the project. The broad coverage of research networks, stakeholder interaction, and strategic support from the cultural heritage community is guaranteed owing to the ongoing collaboration between laboratories and an established international and multidisciplinary reference group.
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