Home About Browse Search
Svenska


In search of control points: A study on the interaction of hydrological fluxes and nitrogen in the boreal landscape

Blackburn, Meredith (2018). In search of control points: A study on the interaction of hydrological fluxes and nitrogen in the boreal landscape. Diss. (sammanfattning/summary) Umeå : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae, 1652-6880 ; 2018:2
ISBN 978-91-7760- 144-9
eISBN 978-91-7760-145-6
[Doctoral thesis]

[img]
Preview
PDF
1MB

Abstract

Nitrogen (N) export from terrestrial ecosystems is strongly influenced by hydrological flux, but losses of reactive N forms through surface waters are generally thought to be under strong biological control. However, losses from terrestrial ecosystems may be fostered by catchment processes that allow N to circumvent biological uptake. The aim of my research was to investigate how boreal landscape attributes interact with hydrological forcing to regulate N delivery to streams. I explored these controls through detailed study of key land-water interfaces, in combination with broader assessments of N concentration and export in the Krycklan Catchment Study (KCS), located in northern Sweden. I found, contrary to the prevailing view, forest riparian zones represented a net source of dissolved organic N (DON) and dissolved inorganic N (DIN) to streams. This pattern is connected to organic-rich riparian soils that promote local N production, potentially decoupling stream N exports from upland forest processes. Mires also acted as important N sources as reduced N in deep peat layers was delivered to streams through preferential flowpaths. At network scales, unique headwater biogeochemical patterns became more synchronous downstream, as mire, forest, and lake signals mixed. Nonetheless, mire and wet riparian areas emerged as important explanatory variables for stream N composition and concentration across the KCS. Finally, the relative importance of hydrological flux as the driver of N export in this system differed according to N form, the temporal scale considered, and catchment structure. DON formed close and consistent relationships with discharge among sites, years, and seasons, while DIN export was more weakly and variably related to flow. Still, surprisingly strong flow-controlled DIN export was observed during snow-free seasons, highlighting the importance of local, riparian N sources. Overall, my results suggest that long term peat accumulation – both in riparian zones and in mires – has created control points that regulate N losses through different mechanisms. The strong influence of these patches may overwhelm the detection of upland forest influences on N export in relatively pristine boreal landscapes.

Authors/Creators:Blackburn, Meredith
Title:In search of control points: A study on the interaction of hydrological fluxes and nitrogen in the boreal landscape
Series/Journal:Acta Universitatis agriculturae Sueciae (1652-6880)
Year of publishing :January 2018
Depositing date:3 January 2018
Volume:2018:2
Number of Pages:44
Papers/manuscripts:
NumberReferences
IM. Blackburn*, José L. J. Ledesma, Torgny Näshilm, Hjalmar Laudon, Ryan A. Sponseller (2017). Evaluating hillslope and riparian contributions to dissolved nitrogen (N) export from a boreal forest catchment. Journal of geophysical research, vol 122 (2), pp. 324-339.
IIRyan A. Sponseller*, M. Blackburn, M. B Nilsson, H. Laudon (2017). Headwater Mires Constitute a Major Source of Nitrogen (N) to Surface Waters in the Boreal Landscape. Ecosystems, vol (issue),
IIIMeredith Blackburn*, Hjalmar Laudon, William Lidberg, Martyn Futter, Ryan A. Sponseller. Landscape regulation of nitrogen delivery to boreal streams (manuscript)
IVMeredith Blackburn*, Hjalmar Laudon, Ryan A. Sponseller. Landscape heterogeneity shapes patterns of supply versus transport control of nitrogen export from a boreal landscape. (manuscript)
Place of Publication:Umeå
Publisher:Department of Forest Ecology and Management,Swedish University of Agricultural Sciences
ISBN for printed version:978-91-7760- 144-9
ISBN for electronic version:978-91-7760-145-6
ISSN:1652-6880
Language:English
Additional Information:Main funding split 50/50 between projects: ForWater and NiCAF both Formas
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:P Natural resources > P10 Water resources and management
Subjects:(A) Swedish standard research categories 2011 > 1 Natural sciences > 105 Earth and Related Environmental Sciences > Geosciences, Multidisciplinary
(A) Swedish standard research categories 2011 > 1 Natural sciences > 105 Earth and Related Environmental Sciences > Geochemistry
(A) Swedish standard research categories 2011 > 1 Natural sciences > 105 Earth and Related Environmental Sciences > Oceanography, Hydrology, Water Resources
(A) Swedish standard research categories 2011 > 1 Natural sciences > 106 Biological Sciences (Medical to be 3 and Agricultural to be 4) > Ecology
(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 401 Agricultural, Forestry and Fisheries > Soil Science
Agrovoc terms:boreal forests, nitrogen cycle, rivers, riparian zones, organic nitrogen compounds, terraces, peatlands, bogs, nitrogen fixation, nitrate
Keywords:nitrogen, disolved organic nitrogen, Ammonium, nitrate, riparian zone, mire, forest, stream, boreal, control point, hot spot
URN:NBN:urn:nbn:se:slu:epsilon-e-4596
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-e-4596
ID Code:14932
Faculty:S - Faculty of Forest Sciences
Department:(S) > Dept. of Forest Ecology and Management
External funders:FORMAS
Deposited By: Meredith Blackburn
Deposited On:09 Jan 2018 10:54
Metadata Last Modified:11 Jan 2018 09:37

Repository Staff Only: item control page

Downloads

Downloads per year (since September 2012)

View more statistics

Downloads
Hits