Understanding phosphorus mobility and bioavailability in the hyporheic zone of a chalk stream
Lapworth, Dan J. 
ORCID: https://orcid.org/0000-0001-7838-7960; Gooddy, Daren C.; Jarvie, Helen P. ORCID: https://orcid.org/0000-0002-4984-1607.
2011
Understanding phosphorus mobility and bioavailability in the hyporheic zone of a chalk stream.
Water, Air and Soil Pollution, 218 (1-4).
213-226.
10.1007/s11270-010-0636-1
Abstract/Summary
This paper investigates the changes in bioavailable phosphorus (P) within the hyporheic zone of a groundwater-dominated chalk stream. In this study, tangential flow fractionation is used to investigate P associations with different size fractions in the hyporheic zone, groundwater and surface water. P speciation is similar for the river and the chalk aquifer beneath the hyporheic zone, with ‘dissolved’ P (<10 kDa) accounting for ~90% of the P in the river and >90% in the deep groundwaters. Within the hyporheic zone, the proportion of ‘colloidal’ (<0.45 μm and >10 kDa) and ‘particulate’ (>0.45 μm) P is higher than in either the groundwater or the surface water, accounting for ~30% of total P. Our results suggest that zones of interaction within the sand and gravel deposits directly beneath and adjacent to river systems generate colloidal and particulate forms of fulvic-like organic material and regulate bioavailable forms of P, perhaps through coprecipitation with CaCO3. While chalk aquifers provide some degree of protection to surface water ecosystems through physiochemical processes of P removal, where flow is maintained by groundwater, ecologically significant P concentrations (20–30 μg/L) are still present in the groundwater and are an important source of bioavailable P during baseflow conditions. The nutrient storage capacity of the hyporheic zone and the water residence times of this dynamic system are largely
| Item Type: | Publication - Article |
|---|---|
| Digital Object Identifier (DOI): | 10.1007/s11270-010-0636-1 |
| Programmes: | BGS Programmes 2010 > Groundwater Science CEH Topics & Objectives 2009 - 2012 > Water > WA Topic 2 - Ecohydrological Processes > WA - 2.1 - Identify and quantify sources, fluxes and pathways of water, chemicals ... |
| UKCEH and CEH Sections/Science Areas: | Acreman |
| ISSN: | 0049-6979 |
| Additional Keywords: | nutrients, phosphorus, hyporheic, groundwater, river, chalk, tangential flow, GroundwaterBGS, Groundwater, Environmental tracers, Groundwater quality, Surface water interaction fractionation (TFF), Catchment Processes |
| NORA Subject Terms: | Ecology and Environment Hydrology |
| Date made live: | 26 May 2011 09:43 +0 (UTC) |
| URI: | https://nora.nerc.ac.uk/id/eprint/12789 |
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