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Widerlund, Anders
Publications (10 of 84) Show all publications
Paulsson, O. & Widerlund, A. (2023). Diel variations in dissolved oxygen concentration and algal growth in the Laver pit lake, northern Sweden. Applied Geochemistry, 155, Article ID 105725.
Open this publication in new window or tab >>Diel variations in dissolved oxygen concentration and algal growth in the Laver pit lake, northern Sweden
2023 (English)In: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 155, article id 105725Article in journal (Refereed) Published
Abstract [en]

The diel oxygen technique relying on automated in-situ measurements of dissolved oxygen was used as an indicator of seasonal and diurnal variations of photosynthesis in the circumneutral Laver pit lake in northern Sweden. From July to September 2017, surface water temperature, electrical conductivity, pH, and dissolved oxygen were continuously measured at a time resolution of 30 min using sensors mounted on a floating buoy. The data could be monitored in real-time using a browser-based software and permitted calculation of gross primary production (GPP), net ecosystem production (NEP), and respiration (R) in the lake. The dissolved O2 concentration showed a consistent pattern of diel variations that reached up to 0.5 mg L−1 during the warmer summer period (July–August). Towards the end of August these variations decreased in magnitude and remained at ∼0.1 mg L−1 throughout September. pH showed diel variations that mimicked those of dissolved O2, with maximum daily variations of 0.4–0.5 pH units during July and August. A seven-day moving average of GPP showed a peak during July to mid-August, and the maximum GPP value of 0.55 mg O2 L−1 day−1 is similar to those found in natural oligotrophic lakes. A phytoplankton sample showed a total biomass concentration of 24 μg L−1, with the species Chrysophyceae, Chlorophyta, and Bacillariophyta occurring in the water. Diel oxygen data indicated that respiration by autotrophs and respiration of autochthonous labile organic matter by heterotrophs dominated in the lake, as is often the case in lakes where planktonic primary production is the main supplier of labile organic carbon. A close coupling between R and GPP suggests that nearly all GPP was respired in the epilimnion. The study shows that the diel oxygen technique can be used for real-time monitoring of seasonal and diurnal variations of dissolved oxygen and pH in pit lakes. This would be a useful technique in pit lake remediation projects where fertilization is used to stimulate algal growth and metal sequestering by algae.

Place, publisher, year, edition, pages
Elsevier Ltd, 2023
Keywords
Diurnal variation, Gross primary production, pH, Phytoplankton, Remediation
National Category
Ecology Environmental Sciences
Research subject
Applied Geochemistry
Identifiers
urn:nbn:se:ltu:diva-99424 (URN)10.1016/j.apgeochem.2023.105725 (DOI)2-s2.0-85163322791 (Scopus ID)
Funder
Luleå University of TechnologyEuropean Regional Development Fund (ERDF)Norrbotten County Council, 20200552J. Gust. Richert stiftelse, 2019–00491; 2020–00595ÅForsk (Ångpanneföreningen's Foundation for Research and Development)
Note

Validerad;2023;Nivå 2;2023-08-10 (joosat);

Licens fulltext: CC BY License

Available from: 2023-08-10 Created: 2023-08-10 Last updated: 2023-09-05Bibliographically approved
Paulsson, O., Widerlund, A. & Conrad, S. (2023). Stimulating algal growth through wood ash fertilization in the Åkerberg pit lake, northern Sweden. Applied Geochemistry, 151, Article ID 105616.
Open this publication in new window or tab >>Stimulating algal growth through wood ash fertilization in the Åkerberg pit lake, northern Sweden
2023 (English)In: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 151, article id 105616Article in journal (Refereed) Published
Abstract [en]

Fifteen microcosms were installed in the Åkerberg pit lake for 15 days in the summer season (July) 2021. To stimulate algal growth, the microcosms were fertilized with two P-rich wood ashes, and KNO3. Chlorophyll-a was used as an indicator of algal growth while filtered (<0.2 μm) and particulate suspended element concentrations (>0.2 μm) were used to estimate algal metal uptake. Water quality measurements and water sampling were conducted on three occasions (every five days) and at the start of the experiment to monitor algal growth. The chlorophyll-a concentration in the microcosms fertilized with wood ash increased from 0.3-0.8 μg/L at the start of the experiment to 53–77 μg/L after 15 days. Algal element uptake of filtered concentrations (<0.2 μm) was observed for many elements including, Ni (33–36%), Zn (22–65%) and Cd (22–54%). This suggests that wood ash could be used to stimulate algal growth in pit lakes by acting as a source for P and potentially also other nutrients. The highest chlorophyll-a concentrations were seen on day 10, indicating that a breakdown of chlorophyll-a impacted the measured concentrations, which otherwise could have been higher.

Place, publisher, year, edition, pages
Elsevier Ltd, 2023
Keywords
Algal growth, Microcosms, Pit lake, Subarctic, Wood ash fertilization
National Category
Ecology Geochemistry
Research subject
Applied Geochemistry
Identifiers
urn:nbn:se:ltu:diva-96186 (URN)10.1016/j.apgeochem.2023.105616 (DOI)2-s2.0-85149678821 (Scopus ID)
Funder
Bio4Energy
Note

Validerad;2023;Nivå 2;2023-03-20 (joosat);

Funder: J Gust Richert Foundation (2021-00678)

Licens fulltext: CC BY License

Available from: 2023-03-20 Created: 2023-03-20 Last updated: 2023-09-05Bibliographically approved
Paulsson, O. & Widerlund, A. (2022). Modelled impact of climate change scenarios on hydrodynamics and water quality of the Rävlidmyran pit lake, northern Sweden. Applied Geochemistry, 139, Article ID 105235.
Open this publication in new window or tab >>Modelled impact of climate change scenarios on hydrodynamics and water quality of the Rävlidmyran pit lake, northern Sweden
2022 (English)In: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 139, article id 105235Article in journal (Refereed) Published
Abstract [en]

Predictive modelling for three climate scenarios, based on the three greenhouse gas emission scenarios RCP 2.6, RCP 4.5 and RCP 8.5, was conducted for the Rävlidmyran pit lake, located in Västerbotten, northern Sweden. The model output for pH, temperature, dissolved oxygen, Cl, Fe3+, and Zn during the 10-year period 2090–2099 was compared to the model output during the 10-year period 2006–2015, for which measured meteorological data was used as input. Changes in thermocline, chemocline and water outflow were also evaluated. The results indicate that the water outflow from the pit lake will increase, as well as the number of days when the temperature in the mixolimnion exceeds 12 °C. The largest changes are seen for the highest greenhouse gas emission scenario (RCP 8.5). A small increase in Zn outflow (4.4%) could be observed for the RCP 8.5 emission scenario compared to the RCP 2.6 scenario. The results also indicate that the stratification of the lake is relatively stable, and it is predicted to remain meromictic for all climate scenarios. However, a sensitivity analysis indicates that a reduction of groundwater inflow element concentrations by 25–50% may result in a weakened stratification of the lake. Minor dilution could be observed in the monimolimnion of the lake as the modelled Cl concentration decreased by ∼0.3 mg/L in the RCP 8.5 emission scenario compared to the 2006–2015 period. The Cl concentration was also lower in the RCP 8.5 scenario compared to the RCP 2.6 and RCP 4.5 scenario, both in the mixolimnion and the monimolimnion.

Place, publisher, year, edition, pages
Elsevier, 2022
Keywords
Climate change, Modelling, Pit lake, PITLAKQ, Skellefte sulphide ore district, Subarctic
National Category
Geochemistry
Research subject
Applied Geochemistry
Identifiers
urn:nbn:se:ltu:diva-89356 (URN)10.1016/j.apgeochem.2022.105235 (DOI)000800103400001 ()2-s2.0-85124808483 (Scopus ID)
Note

Validerad;2022;Nivå 2;2022-02-21 (johcin);

Funder: European Regional Development Fund and Norrbotten County Council (20200552); J Gust Richert Foundation (2018–00409; 2019–00491; 2020–00595); ÅForsk Foundation (19–334)

Available from: 2022-02-21 Created: 2022-02-21 Last updated: 2023-09-05Bibliographically approved
Paulsson, O. & Widerlund, A. (2021). Algal nutrient limitation and metal uptake experiment in the Åkerberg pit lake, northern Sweden. Applied Geochemistry, 125, Article ID 104829.
Open this publication in new window or tab >>Algal nutrient limitation and metal uptake experiment in the Åkerberg pit lake, northern Sweden
2021 (English)In: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 125, article id 104829Article in journal (Refereed) Published
Abstract [en]

A microcosm nutrient limitation experiment was conducted in the Åkerberg pit lake, located in Västerbotten, northern Sweden, in the summer of 2018. The microcosms were fertilized with N, P and N and P in combination. Chlorophyll-a concentrations were used to estimate algal growth. Filtered and suspended metal concentrations of the microcosms were compared to see if an increase in algal growth would lead to higher metal uptake. The results show that the microcosms fertilized with N and P had the highest chlorophyll-a concentrations (3–3.4 μg/l). This corresponds to an increase of 9.5–11 times compared to the initial chlorophyll-a concentrations, suggesting that the lake is nutrient poor with regards to both N and P. An increase of the metal concentration in the suspended particulate samples (>0.2 μm) of the microcosms fertilized with both N and P could be observed particularly for the mining-related metals Cd, Co, Ni, and Zn. The uptake of these metals amounted to 2.5–20% (Cd), 2.6–14% (Co), 0.87–1.8% (Ni), and 19–64% (Zn) of their filtered concentrations (<0.2 μm).

Place, publisher, year, edition, pages
Elsevier, 2021
Keywords
Pit lake, Subarctic, Algal growth, Metal uptake, Nutrient limitation
National Category
Geochemistry
Research subject
Applied Geochemistry; Centre - Centre for Advanced Mining & Metallurgy (CAMM)
Identifiers
urn:nbn:se:ltu:diva-81823 (URN)10.1016/j.apgeochem.2020.104829 (DOI)000612516700005 ()2-s2.0-85097075437 (Scopus ID)
Funder
European Regional Development Fund (ERDF)Norrbotten County CouncilJ. Gust. Richert stiftelseLuleå University of Technology
Note

Validerad;2021;Nivå 2;2021-01-26 (alebob)

Available from: 2020-12-03 Created: 2020-12-03 Last updated: 2023-09-05Bibliographically approved
Pontér, S., Rodushkin, I., Engström, E., Rodushkina, K., Paulukat, C., Peinerud, E. & Widerlund, A. (2021). Early diagenesis of uranium in lakes receiving deep groundwater from the Kiruna mine, northern Sweden. Science of the Total Environment, 793, Article ID 148441.
Open this publication in new window or tab >>Early diagenesis of uranium in lakes receiving deep groundwater from the Kiruna mine, northern Sweden
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2021 (English)In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 793, article id 148441Article in journal (Refereed) Published
Abstract [en]

The uranium (U) concentrations and isotopic composition of waters and sediment cores were used to investigate the transport and accumulation of U in a water system (tailings pond, two lakes, and the Kalix River) receiving mine waters from the Kiruna mine. Concentrations of dissolved U decrease two orders of magnitude between the inflow of mine waters and in the Kalix River, while the concentration of the element bound to particulate matter increases, most likely due to sorption on iron‑manganese hydroxides and organic matter. The vertical distribution of U in the water column differs between two polluted lakes with a potential indication of dissolved U supply from sediment's pore waters at anoxic conditions. Since the beginning of exposure in the 1950s, U concentrations in lake sediments have increased >20-fold, reaching concentrations above 50 μg g-1. The distribution of anthropogenic U between the lakes does not follow the distribution of other mine water contaminants, with a higher relative proportion of U accumulating in the sediments of the second lake.

Concentrations of redox-sensitive elements in the sediment core as well as Fe isotopic composition were used to re-construct past redox-conditions potentially controlling early diagenesis of U in surface sediments. Two analytical techniques (ICP-SFMS and MC-ICP-MS) were used for the determination of U isotopic composition, providing an extra dimension in the understanding of processes in the system. The (234 U)/(238 U) activity ratio (AR) is rather uniform in the tailings pond but varies considerably in water and lake sediments providing a potential tracer for U transport from the Kiruna mine through the water system, and U immobilization in sediments. The U mass balance in the Rakkurijoki system as well as the amount of anthropogenic U accumulated in lake sediments were evaluated, indicating the immobilization in the two lakes of 170 kg and 285 kg U, respectively.

Place, publisher, year, edition, pages
Elsevier, 2021
Keywords
Uranium, Isotope ratios, Mine water, Sediments
National Category
Geochemistry
Research subject
Applied Geochemistry
Identifiers
urn:nbn:se:ltu:diva-83282 (URN)10.1016/j.scitotenv.2021.148441 (DOI)000691588400003 ()34174600 (PubMedID)2-s2.0-85108453840 (Scopus ID)
Funder
Swedish Agency for Economic and Regional Growth
Note

Validerad;2021;Nivå 2;2021-06-28 (johcin);

Artikeln har tidigare förekommit som manuskript i avhandling

Available from: 2021-03-16 Created: 2021-03-16 Last updated: 2023-09-05Bibliographically approved
Pontér, S., Sutliff-Johansson, S., Engström, E., Widerlund, A., Mäki, A., Rodushkina, K., . . . Rodushkin, I. (2021). Evaluation of a Multi-Isotope Approach as a Complement to Concentration Data within Environmental Forensics. Minerals, 11(1), Article ID 37.
Open this publication in new window or tab >>Evaluation of a Multi-Isotope Approach as a Complement to Concentration Data within Environmental Forensics
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2021 (English)In: Minerals, E-ISSN 2075-163X, Vol. 11, no 1, article id 37Article in journal (Refereed) Published
Abstract [en]

Heavy metal contamination was identified in groundwater monitoring wells surrounding a waste deposit facility at the Rönnskär Cu–Pb–Zn smelter in Skellefteå, Northern Sweden, as well as in brackish water and sediments from the nearby harbor. Following an investigative study of the surrounding area, brackish water from the Baltic Sea and sediments from a nearby harbor were also determined to be contaminated. This study investigated the ranges of isotopic compositions of four elements (Cd, Cu, Pb, and Zn) in smelter materials (ores, products, and waste) and polluted groundwater sediments of the affected area. The study’s objective was to evaluate the variability of the polluting source and identify possible isotope fractionation. This study further assesses the viability of using isotopic information to identify the source of the pollutant. These data were used in combination with multi-element screening analysis and multivariate statistical techniques. Expanding the number of elements utilized in isotope tracing empowers our abilities to decipher the source(s) and the extent of environmental exposure from contamination events related to mining and refining operations.

Place, publisher, year, edition, pages
MDPI, 2021
Keywords
isotope ratios, smelter, natural variability, fractionation groundwater contamination, heavy metals
National Category
Geochemistry
Research subject
Applied Geochemistry
Identifiers
urn:nbn:se:ltu:diva-82484 (URN)10.3390/min11010037 (DOI)000610587200001 ()2-s2.0-85099152808 (Scopus ID)
Funder
Swedish Agency for Economic and Regional GrowthNorrbotten County Council
Note

Validerad;2021;Nivå 2;2021-01-18 (alebob)

Available from: 2021-01-18 Created: 2021-01-18 Last updated: 2024-01-17Bibliographically approved
Sutliff-Johansson, S., Pontér, S., Engström, E., Rodushkin, I., Peltola, P. & Widerlund, A. (2021). Tracing anthropogenic sources of Tantalum and Niobium in Bothnian Bay sediments, Sweden. Journal of Soils and Sediments, 21(3), 1488-1503
Open this publication in new window or tab >>Tracing anthropogenic sources of Tantalum and Niobium in Bothnian Bay sediments, Sweden
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2021 (English)In: Journal of Soils and Sediments, ISSN 1439-0108, E-ISSN 1614-7480, Vol. 21, no 3, p. 1488-1503Article in journal (Refereed) Published
Abstract [en]

Purpose This study aims to evaluate temporal trends of Tantalum (Ta) and Niobium (Nb) concentrations in northern Baltic Sea sediments with focus on the potential impact from the Ronnskar sulfide ore smelter, located 15 km east of Skelleftea in northern Sweden. The potential of Ta or Nb to serve as tracers for environmental pollution caused by the electronic waste is compared. Lastly, correlations between Ta and Nb concentrations and those of major redox elements are investigated. Methods A 35-cm-deep core was collected in the harbor bay (Kallholmsfjarden) outside of the smelter. A secondary 6-m-deep sediment core was collected in the deep Bothnian Bay for comparative purposes. Element screening analysis was conducted the using ICP-SFMS for the Kallhomsfjarden core and a combination of ICP-SFMS and ICP-OES for the Bothnian Bay core. In the final analysis, a 5-step sequential extraction technique was preformed to allow for better prediction of the fate and mobility of Ta and Nb. Results and discussion In the vicinity of the smelter, Ta concentration increases from 0.42 to 3.8 ppm from the time coinciding with the beginning of electronic waste processing. Conversely, Nb concentration remained stable at background levels throughout the core at 6.33 +/- 0.78 ppm. The Nb/Ta ratio thus changed from 14.5 to 1.7, reflecting an increase of anthropogenic input of Ta into the bay sediments. In the pre-industrial part of the sediment, concentrations of both elements follow concentration of aluminosilicates in the core. In recent sediments, however, the anthropogenic Ta exhibits an association with hydrous ferric oxides (HFOs) and organic matter. Conclusions Notable increases in Ta concentrations began following the beginning of scrap metal and electronic waste processing at the Ronnskar smelter. Anthropogenic Ta introduced in the upper portion of the sediment and are more associated with HFOs and organic material than natural Ta seen in the deeper parts of the core where detrital Ta is most common. Niobium was not affected by the Ronnskar smelter and displayed no notable change to the preindustrial background.

Place, publisher, year, edition, pages
Springer, 2021
Keywords
Technology-critical elements, Industrial smelter, Niobium, Tantalum, Contamination, Sediment
National Category
Geochemistry
Research subject
Applied Geochemistry
Identifiers
urn:nbn:se:ltu:diva-82257 (URN)10.1007/s11368-020-02852-4 (DOI)000598984200001 ()2-s2.0-85097371429 (Scopus ID)
Funder
Norrbotten County CouncilSwedish Agency for Economic and Regional Growth
Note

Validerad;2021;Nivå 2;2021-03-08 (johcin)

Available from: 2021-01-11 Created: 2021-01-11 Last updated: 2023-09-05Bibliographically approved
Sutliff-Johansson, S., Pontér, S., Mäki, A., Engström, E., Rodushkin, I., Peltola, P. & Widerlund, A. (2020). Groundwater environmental forensic investigation combining multivariate statistical techniques and screening analyses. Environmental Forensics
Open this publication in new window or tab >>Groundwater environmental forensic investigation combining multivariate statistical techniques and screening analyses
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2020 (English)In: Environmental Forensics, ISSN 1527-5922, E-ISSN 1527-5930Article in journal (Refereed) Epub ahead of print
Abstract [en]

Heavy metal contamination was identified in groundwater monitoring wells surrounding a waste deposit facility at the Rönnskär Cu–Pb–Zn smelter in Skellefteå, northern Sweden. The main objective of this study is to identify the sources of contamination, utilizing element screening analyses and multivariate statistical techniques. A second objective is to determine the usefulness of these techniques in Environmental Forensics investigations of contaminated groundwater at a complex industrial site. Water samples were collected from four groundwater monitoring wells and six waste deposit cells surrounding the contaminated area. Seventy-two elements are statistically examined and the dataset is reduced to the variables representative of the contaminated source material from the smelting process. A three-component model is identified and explains 88% of the total variation in the dataset. Component 1 includes concentrations of Cd, Co, Ni, Rb, Re, and Zn. This component displays a high correlation with two of the deposit cells and their associated groundwater monitoring wells. Component 2 is comprised of Sb, Cu, and Mo. This component displays a correlation between all monitoring wells and deposits likely due to the high mobility of these elements as oxyanions. Component 3 is dominated by As and displays high correlation to three older deposit cells representing a completely different source than for Components 1 and 2. The application of screening analyses and multivariate statistics in this study has achieved a meaningful identification of sources of contamination in the investigated area. It was also shown to be useful as an initial survey aiming to optimize a full-scale monitoring program at the site.

Place, publisher, year, edition, pages
Taylor & Francis, 2020
Keywords
Rönnskär, multivariate statistical techniques, principle component analysis, multi-elemental screening, groundwater contamination, heavy metals
National Category
Geochemistry
Research subject
Applied Geochemistry
Identifiers
urn:nbn:se:ltu:diva-81976 (URN)10.1080/15275922.2020.1850571 (DOI)000596328500001 ()2-s2.0-85097008086 (Scopus ID)
Funder
Swedish Agency for Economic and Regional GrowthNorrbotten County Council
Available from: 2020-12-14 Created: 2020-12-14 Last updated: 2023-09-05
Paulsson, O. & Widerlund, A. (2020). Pit lake oxygen and hydrogen isotopic composition in subarctic Sweden: A comparison to the local meteoric water line. Applied Geochemistry, 118, Article ID 104611.
Open this publication in new window or tab >>Pit lake oxygen and hydrogen isotopic composition in subarctic Sweden: A comparison to the local meteoric water line
2020 (English)In: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 118, article id 104611Article in journal (Refereed) Published
Abstract [en]

A local meteoric water line based on rainwater and snow core samples was developed for an area comprising parts of eastern Norrbotten and Västerbotten in northern Sweden. The oxygen and hydrogen isotopic composition of groundwater and water from four pit lakes was compared to the local meteoric water line by line-conditioned excess. The isotopic mass balance method was used to estimate the evaporation over inflow ratio and the residence time of the lakes. The results show that the local meteoric water line for the study area is: δ2H = (7.80 ± 0.09) δ18O + (4.35 ± 1.35) ‰, which is close to the global meteoric water line. The surface water of the four pit lakes all have negative line-conditioned excess values which indicate that they have been affected by evaporation. The groundwater plots on the local meteoric water line making it hard to utilize in a mixing model for a lake where precipitation and groundwater are treated as two different sources. Two scenarios were used to estimate the starting composition of the lakes for the isotopic mass balance method. One was based on the intersection point of the local meteoric water line and the local evaporation line and gave evaporation over inflow ratios ranging from 0.23 to 0.74 and residence times ranging from 7.2 to 44.9 years. The second scenario was based on the weighted average composition of precipitation and gave evaporation over inflow ratios ranging from 0.07 to 0.32 and residence times ranging from 2.8 to 14.9 years.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Pit lakes, Local meteoric water line, Subarctic, Stable isotopes, Isotopic mass balance
National Category
Geochemistry
Research subject
Applied Geochemistry
Identifiers
urn:nbn:se:ltu:diva-78712 (URN)10.1016/j.apgeochem.2020.104611 (DOI)000544889100003 ()2-s2.0-85084334376 (Scopus ID)
Note

Validerad;2020;Nivå 2;2020-05-18 (johcin)

Available from: 2020-04-28 Created: 2020-04-28 Last updated: 2023-09-05Bibliographically approved
Hellman, M., Bonilla-Rosso, G., Widerlund, A., Juhanson, J. & Hallin, S. (2019). External carbon addition for enhancing denitrification modifies bacterial community composition and affects CH4 and N2O production in sub-arctic mining pond sediments. Water Research, 158, 22-33
Open this publication in new window or tab >>External carbon addition for enhancing denitrification modifies bacterial community composition and affects CH4 and N2O production in sub-arctic mining pond sediments
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2019 (English)In: Water Research, ISSN 0043-1354, E-ISSN 1879-2448, Vol. 158, p. 22-33Article in journal (Refereed) Published
Abstract [en]

Explosives used in mining operations release reactive nitrogen (N) that discharge into surrounding waters. Existing pond systems at mine sites could be used for N removal through denitrification and we investigated capacity in tailings and clarification pond sediments at an iron-ore mine site. Despite differences in microbial community structure in the two ponds, the potential denitrification rates were similar, although carbon limited. Therefore, a microcosm experiment in which we amended sediment from the clarification pond with acetate, cellulose or green algae as possible carbon sources was conducted during 10 weeks under denitrifying conditions. Algae and acetate treatments showed efficient nitrate removal and increased potential denitrification rates, whereas cellulose was not different from the control. Denitrifiers were overall more abundant than bacteria performing dissimilatory nitrate reduction to ammonium (DNRA) or anaerobic ammonium oxidation, although DNRA bacteria increased in the algae treatment and this coincided with accumulation of ammonium. The algae addition also caused higher emissions of methane (CH4) and nitrous oxide (N2O). The bacterial community in this treatment had a large proportion of Bacteroidia, sulfate reducing taxa and bacteria known as fermenters. Functional gene abundances indicated an imbalance between organisms that produce N2O in relation to those that can reduce it, with the algae treatment showing the lowest relative capacity for N2O reduction. These findings show that pond sediments have the potential to contribute to mitigating nitrate levels in water from mining industry, but it is important to consider the type of carbon supply as it affects the community composition, which in turn can lead to uwanted processes and increased greenhouse gas emissions.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Algae, Clarification pond, Greenhouse gases, Nitrate removal, Tailings pond, Water treatment
National Category
Geochemistry
Research subject
Applied Geochemistry
Identifiers
urn:nbn:se:ltu:diva-73689 (URN)10.1016/j.watres.2019.04.007 (DOI)000470047700003 ()31009831 (PubMedID)2-s2.0-85064467376 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-05-03 (johcin)

Available from: 2019-04-17 Created: 2019-04-17 Last updated: 2019-06-20Bibliographically approved
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