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  • 1.
    Conrad, Sarah
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Wuttig, Kathrin
    Jansen, Nils
    Rodushkin, Ilia
    Ingri, Johan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    The stability of Fe isotope signatures during low salinity mixing in subarctic estuariesIngår i: Aquatic geochemistry, ISSN 1380-6165, E-ISSN 1573-1421Artikel i tidskrift (Refereegranskat)
  • 2.
    Ingri, Johan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Widerlund, Anders
    Land, M.
    Stockholms Universitet.
    Geochemistry of major elements in a pristine boreal river system: hydrological compartments and flow paths2005Ingår i: Aquatic geochemistry, ISSN 1380-6165, E-ISSN 1573-1421, Vol. 11, nr 1, s. 57-88Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Once or twice weekly, water sampling was undertaken for a two and a half year period in the Kalix River, northern Sweden. Soil water, groundwater, water in tributaries and mire water were also sampled at several occasions. Samples were filtered and analysed for major dissolved elements and TOC. Although only 5 of the bedrock in the Kalix River drainage basin is situated in the Caledonian mountains (mostly schist, with some outcrops of dolomite and limestone), the chemical composition of the river, at the river mouth, is clearly influenced by water from the mountain areas. High dissolved Ca/Mg ratios in June and July indicate a large influence of water from the mountain areas during summer. The dissolved Si/Mg ratio increases when water from the woodland (bedrock consisting of Precambrian granitoids) predominates during snowmelt in May, but the ratio is low during summer when water from the mountains is increased. However, the low Si concentrations in the mountain areas are probably not primarily the result of the different rocks but more a reflection of the less intense weathering of silicate minerals in the mountains. High Si/Mg ratios are closely related to high TOC. All the major dissolved elements, except TOC, are diluted by snowmelt in May. However, the dilution varies for different elements. Based on the interpretations of major element ratios the melt water discharge in May reflects two major compartments in the woodland; peatland areas and the upper section of the soil. During summer and autumn storm events in the woodland most of the storm water originated from peatland. High K/Mg ratios in the river in May are related to water discharge from the upper section of the till. Low S/Mg ratios in the river indicate an influence of mire water from the woodland both during melt water discharge in May and during increased water discharge in autumn. The Ca/Mg ratios in tributaries in the woodland are consistently lower during melt water discharge compared with values in August. The lower Ca/Mg ratio in May probably reflects water that has been in contact with the B-horizon in the till during spring flood. Data show that the TOC discharged during spring flood originates from two major compartments in the landscape, the upper soil profile and peatland. Storm discharge of TOC during the rest of the year originates mostly from peatland.

  • 3.
    Land, Magnus
    et al.
    Luleå University of Technology.
    Öhlander, Björn
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Chemical weathering rates, erosion rates and mobility of major and trace elements in a boreal granitic till2000Ingår i: Aquatic geochemistry, ISSN 1380-6165, E-ISSN 1573-1421, Vol. 6, nr 4, s. 435-460Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Chemical weathering rates and erosionrates of granitic till in northern Sweden have beenestimated. The present-day chemical weathering rate iscompared with the long-term average weathering ratesince the last deglaciation approximately 8,700 yearsago. Also, the present-day release rates of major andtrace elements due to chemical weathering are comparedwith the mobility of these elements in a spodosolprofile as shown by soil water samples from the vadozezone. The estimation of the past weathering rate isbased on elemental depletion trends in a soil profile(typic haplocryod), whereas the present weatheringrate is based on elemental input/output budgets in asmall catchment ...

  • 4.
    Pettersson, Ulf T.
    et al.
    Luleå tekniska universitet.
    Ingri, Johan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Andersson, Per S
    Hydrogeochemical processes in the Kafue River upstream from the Copperbelt mining area2000Ingår i: Aquatic geochemistry, ISSN 1380-6165, E-ISSN 1573-1421, Vol. 6, nr 4, s. 385-411Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Frequent sampling during an annual cycle of dissolved(<0.45 μm) and suspended (>0.45 μm) elementshas been conducted in the Kafue River at Raglan'sFarm, upstream from the mining activities within theCopperbelt Province, Zambia. Additional sampling ofsediment and interstitial pore water was conductedduring low water discharge. The presence of carbonateswithin the drainage basin naturally gives rise to highelement concentrations in the dissolved phase(Ca = 626, Mg = 494, Na = 360 and K = 24 mmol l-1).During the rainy season the relative composition ofthe dissolved elements indicated a wash out ofaccumulated weathering products and mineralisedorganic material from the unsaturated zone of the soilprofile. High concentrations of dissolved Al, Fe andMn were measured during high water discharge. At lowwater discharge the sediment was a major source of Fe,Mn and associated Co and Cu to the water column.Enhanced concentrations of dissolved and suspended S,Co and Cu during the rainy season indicated thatatmospheric deposited particles from the mining areawere washed out into the river. Autochthonousformation of particles rich in Si indicated diatomproduction during low water discharge.

  • 5.
    Siergieiev, Dmytro
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Widerlund, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Lundberg, Angela
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Drugge, Lisbeth
    Collomp, Magali
    Ingri, Johan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Öhlander, Björn
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Impact of Hydropower Regulation on River Water Composition in Northern Sweden2014Ingår i: Aquatic geochemistry, ISSN 1380-6165, E-ISSN 1573-1421, Vol. 20, nr 1, s. 59-80Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Using hydrogeochemical analysis of two large boreal rivers (pristine Kalix and hydropower regulated Lule) discharging into the Gulf of Bothnia, the major impacts of regulation on water discharge, element transport, and their seasonal redistribution have been assessed. The pre-regulation hydrogeochemical features were assumed to be similar for the two rivers. For the Lule River, the average maximum runoff was almost halved, while the average minimum was tripled as a result of the regulation. The fraction of winter transport of total organic carbon (TOC), Fe, Si, suspended Mn and P in the Lule River was, according to a conservative estimate, two to three times higher than in the pristine river. Longer residence time in the Lule River delayed arrival of the suspended Mn peak and dissolved Si decline to the river mouth. During summer, the suspended C/N ratio in the regulated river was 10-20 compared to <10 for the pristine, suggesting presence of predominantly old organic material. This was supported by a virtually constant suspended P/Fe ratio throughout the year in the Lule River, indicating low abundance of phytoplankton. TOC varied irregularly in the Lule River suggesting temporal disconnection between the river and the upper riparian zone. The disappearance of the spring flow maximum, a shift of element transport from spring to winter, and supply of mainly old organic material during the vegetation growth season may have a pronounced impact on the ecosystem of the Gulf of Bothnia and the river itself.

  • 6.
    Widerlund, Anders
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Ingri, Johan
    Redox cycling of iron and manganese in sediments of the Kalix River estuary, northern Sweden1996Ingår i: Aquatic geochemistry, ISSN 1380-6165, E-ISSN 1573-1421, Vol. 2, nr 2, s. 185-201Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Iron and manganese redox cycling in the sediment - water interface region in the Kalix River estuary was investigated by using sediment trap data, pore-water and solid-phase sediment data. Nondetrital phases (presumably reactive Fe and Mn oxides) form substantial fractions of the total settling flux of Fe and Mn (51% of Fetotal and 84% of Mntotal). A steady-state box model reveals that nondetrital Fe and Mn differ considerably in reactivity during post-depositional redox cycling in the sediment. The production rate of dissolved Mn (1.6 mmol m-2 d-1) exceeded the depositional flux of nondetrital Mn (0.27 mmol m-2 d-1) by a factor of about 6. In contrast, the production rate of upwardly diffusing pore-water Fe (0.77 mmol m-2 d-1) amounted to only 22% of the depositional flux of nondetrital Fe (3.5 mmol m-2 d-1). Upwardly diffusing pore-water Fe and Mn are effectively oxidized and trapped in the oxic surface layer of the sediment, resulting in negligible benthic effluxes of Fe and Mn. Consequently, the concentrations of nondetrital Fe and Mn in permanently deposited, anoxic sediment are similar to those in the settling material. Reactive Fe oxides appear to form a substantial fraction of this buried, non-detrital Fe. The in-situ oxidation rates of Fe and Mn are tentatively estimated to be 0.51 and 0.16-1.7 mol cm-3 d-1, respectively

  • 7.
    Öhlander, Björn
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Land, Magnus
    Mistra Council for Evidence-based Environmental Management (EviEM), The Royal Swedish Academy of Sciences.
    Ingri, Johan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Widerlund, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Mobility and transport of Nd isotopes in the Vadose zone during weathering of granitic till in a boreal forest2014Ingår i: Aquatic geochemistry, ISSN 1380-6165, E-ISSN 1573-1421, Vol. 20, nr 1, s. 1-17Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    There is a broad correlation between the εNd values for rivers (including both the water and the particulate material it carries) and the age of the source terrain. This paper presents Nd isotope distribution data for soil, soil water, groundwater, and stream water samples gathered in a small catchment in northern Sweden. The results show that the release of Nd and Sm from boreal forests into streams and, eventually, into the oceans is more complicated than previously realized. The weathering of till causes changes in both the Nd isotopic composition and Sm/Nd ratios. Both the Sm/Nd ratio and εNd were higher in strongly weathered soils horizons than in less weathered till, since minerals with high Sm/Nd ratios were, on average, more resistant to weathering than those with low Sm/Nd ratios. In contrast to the situation for the main minerals and the major elements, the weathering of rare earth elements (REE) was not restricted to the E-horizon: the measured REE concentrations continued to increase with depth in the C-horizon. In addition, REE released by weathering in the upper parts of the soil profile were partly secondarily retained at deeper levels. Therefore, the dissolved Nd released by weathering in the upper soil horizons was trapped and did not enter the groundwater directly. Rather, the Nd in the groundwater largely originated from weathering within the groundwater zone. However, this was not the only source of Nd in the stream water. The Nd isotope composition and Sm/Nd ratio were determined by the mixing between of Nd and Sm in the groundwater and REE-carrying organic material washed out of the soil profile. The groundwater close to the stream reaches the upper soil horizons during high discharge events such as snowmelts, and organic matter carrying Nd and Sm is washed out of the soils and thus released into the stream. Therefore, the Nd exported from catchment is derived from both the weathering within the groundwater zone, and the organic matter washed out from the soil. If longer timescales with more advanced weathering stages in the groundwater zone are considered, it cannot be ruled out that there will be a shift towards more radiogenic values in the exported Nd. Recorded shifts in the Nd isotopic composition in the ocean may thus not only reflect changed source regions, but also the weathering history of the same source region

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