Impacts of land-use on concentrations of nutrients in runoffs: Preliminary results in small catchment areas.

Hakala, Ilpo; Huitu, Eeva; Mäkelä, Suvi; Арвола, Лаури

doi:10.1127/lr/13/2002/285

Cited by 2 publications

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“…Dissolved organic carbon as well as ammonium increased from the forest-dominated S1 to the S3 and S4, where peatland contributed more to the water quality, agreeing with the previous findings on the higher proportion of peatland in the catchment increasing DOC concentrations (Huotari et al 2013;Laine et al 2014), and on high ammonium loading coming from drained peatlands (Laine et al 2013;Arvola et al 2015). Nitrite + nitrate, phosphate, TN and TP peaked at agriculture-dominated S2, as observed previously in Löytynoja and in other agriculture-affected streams (Hakala et al 2002;Inwood et al 2005). In contrast to water chemistry, sediment quality (%C, %N, and LOI%) varied less consistently, being high both at S2 and S4, although these points had a different land-use coverage.…”

Section: Environmental Variables and Denitrification Ratessupporting

confidence: 91%

“…1). More information of the stream can be found from Hakala et al (2002), Huotari et al (2013), and Arvola et al (2015). The catchment area for each sampling point was delineated from digital elevation model (pixel size 2 m) based on a laser scanning (National Land Survey of Finland 2016), and the proportions of different land-use types (i.e.…”

Section: Sample and Data Collectionmentioning

confidence: 99%

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Denitrifying microbial communities along a boreal stream with varying land-use

et al. 2019

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Streams have an important role in regulating nitrogen (N) transportation from terrestrial ecosystems to downstream waters. Here, we examined how catchment land-use affects potential denitrification rates and the function and composition of denitrifier communities in boreal stream sediments, using stable isotope incubations and qPCR and 454-pyrosequencing targeted on nirS, nirK and nosZ genes. Although land-use influenced the water chemistry as higher nitrite + nitrate (NO x −) concentration at the agriculture-affected sampling point, sediment organic matter content was found to be the key factor in regulating potential denitrification rates. However, the abundance as well as the diversity and community composition of denitrifying microbes, and genetic N 2 O production potential (the ratio between nirS + nirK and nosZ gene abundances) were connected to both NO x − and sediment quality. Overall, our results suggest that catchment land-use-driven changes in N and carbon availability affect the denitrification rates, and possibly N 2 :N 2 O production ratio, in boreal streams, through altering denitrifier abundance and community composition.

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Section: Environmental Variables and Denitrification Ratessupporting

confidence: 91%

Section: Sample and Data Collectionmentioning

confidence: 99%

Denitrifying microbial communities along a boreal stream with varying land-use

et al. 2019

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“…Mean residence time of water is 3.3 years. The catchment area (199 km 2 ) is dominated by coniferous forests (59%), and agricultural land and peatlands cover 15% and 11% of the catchment area, respectively [ Hakala et al , 2002]. The lake water is neutral (pH 7.0–7.6), although strongly affected by allochthonous organic carbon; the concentration of dissolved organic carbon (DOC) is 10–13 mg L −1 [ Arvola et al , 1996] (Table 1).…”

Section: Methodsmentioning

confidence: 99%

CO₂ and CH₄ fluxes during spring and autumn mixing periods in a boreal lake (Pääjärvi, southern Finland)

et al. 2009

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[1] The greatest gas loss from dimictic lakes occur during spring and autumn mixing periods. Thus, we measured daily concentration gradients of carbon gases (CO 2 and CH 4 ) in mesohumic Lake Pääjärvi during the mixing periods in autumn 2004 and spring 2005 and calculated and compared the fluxes using three different methods: the boundary layer diffusion model (DCO 2 and DCH 4 ), floating static chambers (FC), and changes in gas storage. CO 2 fluxes were higher in autumn than in spring, whereas CH 4 fluxes were lower in autumn than in spring. The method based on changes in storage underestimated the fluxes whereas the floating chambers and the boundary layer diffusion models resulted in similar estimates. However, the chambers always yielded somewhat higher fluxes. Total DCO 2 flux in autumn was 883 mmol m À2 and in spring, 666 mmol m À2, whereas total DCH 4 fluxes were 0.60 mmol m À2 and 0.80 mmol m À2 in autumn and spring, respectively. We calculated gas transfer velocities (k 600 ) to explain the near surface exchange mechanism and the difference between the results based on diffusion models and chambers. Wind speed and k 600 showed significant correlation. In spring the transfer velocity at similar wind speed was higher compared to the autumn. Weekly measurements of algal primary production and community respiration revealed that the lake was net heterotrophic in autumn as well as in spring. Our study showed that the excess CO 2 from the lake metabolism contributed significantly to the CO 2 fluxes during the mixing periods, violating the primary assumption used in the storage method.Citation: López Bellido, J., T. Tulonen, P. Kankaala, and A. Ojala (2009), CO 2 and CH 4 fluxes during spring and autumn mixing periods in a boreal lake (Pääjärvi, southern Finland),

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Impacts of land-use on concentrations of nutrients in runoffs: Preliminary results in small catchment areas.

Cited by 2 publications

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Denitrifying microbial communities along a boreal stream with varying land-use

Denitrifying microbial communities along a boreal stream with varying land-use

CO₂ and CH₄ fluxes during spring and autumn mixing periods in a boreal lake (Pääjärvi, southern Finland)

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Impacts of land-use on concentrations of nutrients in runoffs: Preliminary results in small catchment areas.

Cited by 2 publications

References 0 publications

Denitrifying microbial communities along a boreal stream with varying land-use

Denitrifying microbial communities along a boreal stream with varying land-use

CO2 and CH4 fluxes during spring and autumn mixing periods in a boreal lake (Pääjärvi, southern Finland)

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Product

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CO₂ and CH₄ fluxes during spring and autumn mixing periods in a boreal lake (Pääjärvi, southern Finland)