TY - JOUR

T1 - Determining the impact of riparian wetlands on nutrient cycling, storage and export in permeable agricultural catchments

AU - Johnes, P.J.

AU - Gooddy, D.C.

AU - Heaton, T.H.E.

AU - Binley, A.

AU - Kennedy, M.P.

AU - Shand, P.

AU - Prior, H.

PY - 2020/1/6

Y1 - 2020/1/6

N2 - The impact of riparian wetlands on the cycling, retention and export of nutrients from land to water varies according to local environmental conditions and is poorly resolved in catchment management approaches. To determine the role a specific wetland might play in a catchment mitigation strategy, an alternative approach is needed to the high-frequency and spatially detailed monitoring programme that would otherwise be needed. Here, we present a new approach using a combination of novel and well-established geochemical, geophysical and isotope ratio methods. This combined approach was developed and tested against a 2-year high-resolution sampling programme in a lowland permeable wetland in the Lambourn catchment, UK. The monitoring programme identified multiple pathways and water sources feeding into the wetland, generating large spatial and temporal variations in nutrient cycling, retention and export behaviours within the wetland. This complexity of contributing source areas and biogeochemical functions within the wetland were effectively identified using the new toolkit approach. We propose that this technique could be used to determine the likely net source/sink function of riparian wetlands prior to their incorporation into any catchment management plan, with relatively low resource implications when compared to a full high-frequency nutrient speciation and isotope geochemistry-based monitoring approach.

AB - The impact of riparian wetlands on the cycling, retention and export of nutrients from land to water varies according to local environmental conditions and is poorly resolved in catchment management approaches. To determine the role a specific wetland might play in a catchment mitigation strategy, an alternative approach is needed to the high-frequency and spatially detailed monitoring programme that would otherwise be needed. Here, we present a new approach using a combination of novel and well-established geochemical, geophysical and isotope ratio methods. This combined approach was developed and tested against a 2-year high-resolution sampling programme in a lowland permeable wetland in the Lambourn catchment, UK. The monitoring programme identified multiple pathways and water sources feeding into the wetland, generating large spatial and temporal variations in nutrient cycling, retention and export behaviours within the wetland. This complexity of contributing source areas and biogeochemical functions within the wetland were effectively identified using the new toolkit approach. We propose that this technique could be used to determine the likely net source/sink function of riparian wetlands prior to their incorporation into any catchment management plan, with relatively low resource implications when compared to a full high-frequency nutrient speciation and isotope geochemistry-based monitoring approach.

KW - nitrogen

KW - phosphorus

KW - nutrient cycling

KW - biogeochemistry

KW - geochemistry

KW - geophysics

KW - wetlands

KW - catchment management

U2 - 10.3390/w12010167

DO - 10.3390/w12010167

M3 - Journal article

VL - 12

JO - Water (Switzerland)

JF - Water (Switzerland)

SN - 2073-4441

IS - 1

M1 - 167

ER -