baseflow
; catchment
; European Union
; flux measurement
; nitrogen cycle
; oxic conditions
; preferential flow
; redox potential
; river bed
; river pollution
; stream bed
; surface water
; water quality
; Cumbria
; England
; Leith River
; United Kingdom
英文摘要:
Water pathways through permeable riverbeds are multi-dimensional, including lateral hyporheic exchange flows as well as vertical (upwelling and downwelling) fluxes. The influence of different pathways of water on solute patterns and the supply of nitrate and other redox-sensitive chemical species in the riverbed is poorly understood but could be environmentally significant. For example, nitrate-rich upwelling water in the gaining reaches of groundwater-fed rivers has the potential to supply significant quantities of nitrate through the riverbed to surface waters, constraining opportunities to deliver the goals of the EU Water Framework Directive to achieve 'good ecological status'. We show that patterns in porewater chemistry in the armoured river bed of a gaining reach (River Leith, Cumbria) reflect the spatial variability in different sources of water; oxic conditions being associated with preferential discharge from groundwater and reducing conditions with longitudinal and lateral fluxes of water due to water movement from riparian zones and/or hyporheic exchange flows. Our findings demonstrate the important control of both vertical and lateral water fluxes on patterns of redox-sensitive chemical species in the river bed. Furthermore, under stable, baseflow conditions (
School of Geography, Queen Mary University of London, Mile End Road, London, E1 4NS, United Kingdom; Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, United Kingdom; School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, United Kingdom; School of Physical and Geographical Sciences, Keele University, Staffordshire, ST5 5BG, United Kingdom; School of Natural Sciences and Psychology, Liverpool John Moores University, Liverpool, L3 3AF, United Kingdom
Recommended Citation:
Heppell C.,Louise Heathwaite A.,Binley A.,et al. Interpreting spatial patterns in redox and coupled water-nitrogen fluxes in the streambed of a gaining river reach[J]. Biogeochemistry,2014-01-01,117(2018-02-03)