| 1. |
- Agstam-Norlin, O., et al.
(författare)
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A 25-year retrospective analysis of factors influencing success of aluminum treatment for lake restoration
- 2021
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Ingår i: Water Research. - : Elsevier BV. - 0043-1354 .- 1879-2448. ; 200
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Tidskriftsartikel (refereegranskat)abstract
- For more than 50 years, aluminum (Al)-salts have been used with varying degrees of success to inactivate excess mobile phosphorus (P) in lake sediments and restore lake water quality. Here, we analyzed the factors influencing effectiveness and longevity of Al-treatments performed in six Swedish lakes over the past 25 years. Trends in post-treatment measurements of total phosphorus (TP), Chlorophyll a (Chl_a), Secchi disk depth (SD) and internal P loading rates (Li) were analyzed and compared to pre-treatment conditions. All measured water quality parameters improved significantly during at least the first 4 years post-treatment and determination of direct effects of Al-treatment on sediment P release (Li) was possible for three lakes. Improvements in TP (-29 to -80%), Chl_a (-50 to -78%), SD (7 to 121%) and Li (-68 to -94%) were observed. Treatment longevity, determined via decreases in surface water TP after treatment, varied from 7 to >47 years. Lake type, Al dose, and relative watershed area were related to longevity. In addition, greater binding efficiency between Al and P was positively related to treatment longevity, which has not previously been shown. Our findings also demonstrate that adequate, long-term monitoring programs, including proper determination of external loads, are crucial to document the effect of Al-treatment on sediment P release and lake water quality.
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| 2. |
- Ahlgren, Joakim, et al.
(författare)
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Biogenic phosphorus in oligotropic mountain lake sediments: Differences in composition measured with NMR spectroscopy
- 2006
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Ingår i: Water Research. - Uppsala Univ, Dept Phys & Analyt Chem, S-75124 Uppsala, Sweden. Univ So Denmark, Inst Biol, DK-5230 Odense M, Denmark. Uppsala Univ, Dept Organ & Biol Chem, S-75123 Uppsala, Sweden. Uppsala Univ, Dept Ecol & Evolut, EBC, S-75236 Uppsala, Sweden. : Elsevier BV. - 0043-1354 .- 1879-2448. ; :40, s. 3705-3712
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Tidskriftsartikel (refereegranskat)
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| 3. |
- Ahlgren, Joakim, et al.
(författare)
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Degradation of organic phosphorus compounds in anoxic Baltic Sea sediments : A P-31 nuclear magnetic resonance study
- 2006
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Ingår i: Limnology and Oceanography. - Uppsala Univ, Dept Ecol & Evolut, Evolutionary Biol Ctr, S-75236 Uppsala, Sweden. Uppsala Univ, Dept Chem, S-75124 Uppsala, Sweden. Univ So Denmark, Inst Biol, DK-5230 Odense, Denmark.. - 0024-3590 .- 1939-5590. ; 51:5, s. 2341-2348
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Tidskriftsartikel (refereegranskat)abstract
- The composition and abundance of phosphorus extracted by NaOH-ethylenediaminetetraacetic acid from anoxic Northwest Baltic Sea sediment was characterized and quantified using solution P-31 nuclear magnetic resonance. Extracts from sediment depths down to 55 cm, representing 85 yr of deposition, contained 18.5 g m(-2) orthophosphate. Orthophosphate monoesters, teichoic acid P, microbial P lipids, DNA P, and pyrophosphate corresponded to 6.7, 0.3, 1.1, 3.0, and 0.03 g P m(-2), respectively. The degradability of these compound groups was estimated by their decline in concentration with sediment depth. Pyrophosphate had the shortest half-life (3 yr), followed by microbial P lipids with a half-life of 5 yr, DNA P (8 yr), and orthophosphate monoesters (16 yr). No decline in concentration with sediment depth was observed for orthophosphate or teichoic acid P.
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| 4. |
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| 5. |
- Ahlgren, Joakim, 1972-
(författare)
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Organic Phosphorus Compounds in Aquatic Sediments : Analysis, Abundance and Effects
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Phosphorus (P) is often the limiting nutrient in lacustrine and brackish eco-systems, and enhanced input of P into an aquatic system might therefore negatively impact the environment. Because modern waste water manage-ment have reduced external P input to surface waters, internal P loading from the sediment has become one of the main P sources to aquatic ecosys-tems, in which relatively unknown organic P compounds seem to be more active in P recycling than previously thought. This thesis focus is on improving analysis methods for organic P com-pounds in lacustrine and brackish sediments, as well as determining which of these compounds might be degraded, mobilized and subsequently recycled to the water column and on what temporal scale this occur. In both lacustrine and brackish environments, the most labile P compound was pyrophosphate, followed by different phosphate diesters. Phosphate monoesters were the least labile organic P compounds and degraded the slowest with sediment depth. In regulated lakes, it was shown that pyrophosphate and polyphos-phate compound groups were most related to lake trophic status, thus indi-cating their involvement in P cycling. This thesis also indicates faster P turn-over in sediment from the brackish environment compared to sediment from the lacustrine environment. A comparison of organic P extraction procedures showed that pre-extraction with EDTA, and NaOH as main extractant, was most efficient for total P extraction. Using buffered sodium dithionite (BD) as a pre-extractant and NaOH as main extractant was most efficient for extracting the presuma-bly most labile organic P compound groups, pyrophosphate and polyphos-phate. Furthermore, it was determined that organic P compounds associated with humic substances were more recalcitrant than other P compounds, that the BD step used in traditional P fractionation might extract phosphate monoesters, and that NMR is a statistically valid method for quantification of organic P compounds in sediment extracts.
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| 6. |
- Ahlgren, Joakim, et al.
(författare)
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Release of Organic P Forms from Lake Sediments
- 2011
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Ingår i: Water Research. - : Elsevier BV. - 0043-1354 .- 1879-2448. ; 45:2, s. 565-572
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Tidskriftsartikel (refereegranskat)abstract
- The effects of different physical and chemical conditions on the decomposition and release of organic and inorganic P compound groups from the sediment of Lake Erken were investigated in a series of laboratory experiments. Conditions investigated were temperature, oxygen level, and the effects of additions of carbon substrate (glucose) and poison (formalin). The effects on the P compound groups were determined by measurements with 31P NMR before and after the experiments, as well as analysis of P in effluent water throughout the experiment. Phosphate analysis of the effluent water showed that oxygen level was the most influential in terms of release rates, with the sediments under anoxic conditions generally releasing more phosphate than the other treatments. 31P NMR showed that the various treatments did influence the P compound group composition of the sediment. In particular, the addition of glucose led to a decrease in orthophosphate and polyphosphate while the addition of formalin led to a decrease in phosphorus lipids, DNAphosphate and polyphosphate. Oxic conditions resulted in an increase in polyphosphates, and anoxic conditions in a decrease in these. Temperature did not seem to affect the composition significantly.
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| 7. |
- Ahlgren, Joakim, et al.
(författare)
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Sediment Depth Attenuation of Biogenic Phosphorus Compounds Measured by 31P NMR
- 2005
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Ingår i: Environmental Science and Technology. - Univ Uppsala, Dept Analyt Chem, SE-75124 Uppsala, Sweden. Univ Uppsala, Dept Ecol & Evolut, Uppsala, Sweden. Univ Uppsala, Dept Organ Chem, SE-75124 Uppsala, Sweden. : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 39:3, s. 867-872
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Tidskriftsartikel (refereegranskat)abstract
- Being a major cause of eutrophication and subsequent loss of water quality, the turnover of phosphorus (P) in lake sediments is in need of deeper understanding. A major part of the flux of P to eutrophic lake sediments is organically bound or of biogenic origin. This P is incorporated in a poorly described mixture of autochthonous and allochthonous sediment and forms the primary storage of P available for recycling to the water column, thus regulating lake trophic status. To identify and quantify biogenic sediment P and assess its lability, we analyzed sediment cores from Lake Erken, Sweden, using traditional P fractionation, and in parallel, NaOH extracts were analyzed using 31P NMR. The surface sediments contain orthophosphates (ortho-P) and pyrophosphates (pyro-P), as well as phosphate mono- and diesters. The first group of compounds to disappear with increased sediment depth is pyrophosphate, followed by a steady decline of the different ester compounds. Estimated half-life times of these compound groups are about 10 yr for pyrophosphate and 2 decades for mono- and diesters. Probably, these compounds will be mineralized to ortho-P and is thus potentially available for recycling to the water column, supporting further growth of phytoplankton. In conclusion, 31P NMR is a useful tool to asses the bioavailability of certain P compound groups, and the combination with traditional fractionation techniques makes quantification possible.
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| 8. |
- Ahlgren, Joakim, et al.
(författare)
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Sediment Phosphorus Extractants for Phosphorus-31 Nuclear Magnetic Resonance Analysis : A Quantitative Evaluation
- 2007
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Ingår i: Journal of Environmental Quality. - Uppsala Univ, Dept Phys & Analyt Chem, S-75124 Uppsala, Sweden. Univ So Denmark, Inst Biol, DK-5230 Odense M, Denmark. Uppsala Univ, Dept Biochem & Organ Chem, S-75124 Uppsala, Sweden. Uppsala Univ, Dept Ecol & Evolut, S-75123 Uppsala, Sweden. : Wiley. - 0047-2425 .- 1537-2537. ; 36:3, s. 892-898
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Tidskriftsartikel (refereegranskat)abstract
- The influence of pre-extractant, extractant, and post-extractant on total extracted amounts of P and organic P compound groups measured with 31P nuclear magnetic resonance (31P-NMR) in lacustrine sediment was examined. The main extractants investigated were sodium hydroxide (NaOH) and sodium hydroxide ethylenediaminetetraacetic acid (NaOH-EDTA) with bicarbonate buffered dithionite (BD) or EDTA as pre-extractants. Post extractions were conducted using either NaOH or NaOH-EDTA, depending on the main extractant. Results showed that the most efficient combination of extractants for total P yield was NaOH with EDTA as pre-extractant, yielding almost 50% more than the second best procedure. The P compound groups varying the most between the different extraction procedures were polyphosphates and pyrophosphates. NaOH with BD as pre-extractant was the most efficient combination for these compound groups.
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| 9. |
- Andrén, Cecilia M., et al.
(författare)
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Toxicity of inorganic aluminium at spring snowmelt—In-stream bioassays withbrown trout (Salmo trutta L.)
- 2012
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 437, s. 422-432
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Tidskriftsartikel (refereegranskat)abstract
- Although the acid load has decreased throughout Scandinavia, acidic soils still mobilise aluminium (Al) thatis harmful to brown trout. We hypothesise that there are thresholds for Al toxicity and that the toxicity can betraced from the water content to gill accumulation and the consequential physiological effects. During snowmelt,yearlings were exposed to a gradient of pH and inorganic monomeric Al (Ali) in humic streams to studythe toxic effects and mortality. Gill Al and physiological blood analyses [haemoglobin (Hb), plasma chloride(P-Cl) and glucose (Glu)] were measured. As the water quality deteriorated, Al accumulated on the gills; Hband Glu increased; P-Cl decreased, and mortality occurred. Moribund fish had significantly increased gill Aland Hb, suggesting that respiratory disturbances contributed to mortality. Decreased P-Cl and plasmaavailability indicated an ion regulatory disturbance and possibly circulatory collapse. Ali should be lessthan 20 μg/L, and pH higher than 5.0, to sustain healthy brown trout populations. These thresholds can beused to fine-tune lime dose, as both Ali and pH levels have to be balanced to prevent harm in the recoveringaquatic biota. Although Al is tightly linked to pH, local variation in Al availability in soil and bedrock affectsthe Al release and subsequent toxic Ali episodes in some catchment areas.
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| 10. |
- Andrén, Cecilia M., 1964-
(författare)
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Toxicity of Inorganic Aluminium in Humic Streams
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Aluminium (Al) has been recognised as a main toxic factor alongside pH in acidified water ecosystems. The toxic effect of Al has been attributed to inorganic Al (Ali), though there are few in situ studies in ambient humic waters which are the focus of this thesis.The aim was to estimate Ali toxicity and thus also Ali concentrations in Swedish humic streams. Subsequently it is necessary to analyse Ali correctly, which was studied by modelling and method intercalibrations. The hypothesis was that the effect of Ali could be followed via physiological effects and Al accumulation, as well as by mortality. Toxicity was studied by in stream exposures of brown trout (Salmo trutta L.) and two salmonid prey organisms (Gammarus pulex and Baetis rhodani) during spring flood.The modelling of the Ali fraction was performed using monitoring data covering all of Sweden with satisfactory results. The essential variables for Ali modelling were determined; Al, DOC, pH and F, while Fe, Ca and Mg had less effect. The automated analytical procedure for Ali (with cation exchange followed by complexation with pyrocatechol violet) was modified and validated and showed to be the preferred method for laboratory analyses.To avoid detrimental effects for brown trout Ali should be <20 µg/L and pH >5.0; mortality was high when the Ali was above 50 µg/L. The invertebrates were more sensitive, as mortalities occurred at pH <6.0 and Ali >15 µg/L for G. pulex, and at pH <5.7 and Ali >20 µg/L for B. rhodani. It is prudent to use a wide view and let the most sensitive species set the tolerance limits; a pH above 5.7-6.0 and Ali below 15-20 µg/L allows the stream ecosystems to thrive.Today, as waters are recovering from acidification, the aim of mitigating liming is to carefully adjust dosage to avoid suboptimal water quality. The thresholds found in this thesis can be used to efficiently but carefully decrease liming, as both Ali and pH levels have to be balanced to sustain the recovering aquatic biota.
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