Redox-induced phosphorus release from critical source areas following rainfall events in New Zealand

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dc.citation.issueFebruary 2025
dc.citation.volume374
dc.contributor.authorPalihakkara J
dc.contributor.authorBurkitt L
dc.contributor.authorJeyakumar P
dc.contributor.authorAttanayake CP
dc.coverage.spatialEngland
dc.date.accessioned2025-01-27T20:31:35Z
dc.date.available2025-01-27T20:31:35Z
dc.date.issued2025-02
dc.description.abstractCritical source areas (CSAs) can act as a source of phosphorus (P) during intermittent rainfall events and contribute to dissolved P loss via runoff. Dissolved forms of P are readily accessible for plant and algal uptake; hence it is a concern in terms of the eutrophication of freshwater bodies. The potential of CSAs to release dissolved P to surface runoff upon intermittent short-term submergence caused by different rainfall events has not been studied at a field-scale in New Zealand previously. A field study was conducted to investigate the potential of two different pastoral soil CSAs (Recent and Pallic soil) to release soil P over five rainfall events during winter and to explore the mechanisms of P release in these soils. Ten sampling stations were installed within each CSA in an area of 6 × 2 m2. Each sampling station had two porewater samplers installed at two depths (2 and 10 cm) below the soil surface. Two platinum half-cell electrodes were installed at the same two depths. Porewater and floodwater samples were collected following five rainfall events. Redox potentials were measured in-situ. Dissolved reactive phosphorus (DRP), pH, dissolved organic carbon, cations, anions, and alkalinity of the water samples were measured. Soil chemical P fractions were assessed at the beginning, middle and end of the experiment. Thermodynamic modelling was used to infer dissolution and formation of P and P-associated minerals. The average porewater DRP at the two depths during the rainfall events of the Recent and Pallic soils were 0.32-1.3 mg L-1 and 0.26-2.31 mg L-1, respectively. The average floodwater DRP concentrations of the Recent and Pallic soils were 35 and 43-fold higher than the target DRP concentration (0.01 mg L-1) for the Manawatū River. The study highlights the substantial risk of P loss from CSAs to surface water, driven primarily by the reductive dissolution of Fe and Mn oxy(hydr)oxides. The findings underscore the importance of targeted management strategies to mitigate dissolved P runoff, particularly in high-risk CSAs frequent submerged during rainfall events. This study developed an effective method for monitoring soil porewater P and redox conditions, offering valuable insights and practical tools for resource managers seeking to reduce P contamination.
dc.description.confidentialfalse
dc.format.pagination124006-
dc.identifier.author-urlhttps://www.ncbi.nlm.nih.gov/pubmed/39765061
dc.identifier.citationPalihakkara J, Burkitt L, Jeyakumar P, Attanayake CP. (2025). Redox-induced phosphorus release from critical source areas following rainfall events in New Zealand.. J Environ Manage. 374. February 2025. (pp. 124006-).
dc.identifier.doi10.1016/j.jenvman.2024.124006
dc.identifier.eissn1095-8630
dc.identifier.elements-typejournal-article
dc.identifier.issn0301-4797
dc.identifier.number124006
dc.identifier.piiS0301-4797(24)03993-8
dc.identifier.urihttps://mro.massey.ac.nz/handle/10179/72413
dc.languageeng
dc.publisherElsevier Ltd, United Kingdom
dc.relation.isPartOfJ Environ Manage
dc.rights(c) The author/sen
dc.rights.licenseCC BYen
dc.rights.urihttps://creativecommons.org/licenses/by/4.0/en
dc.subjectCritical source areas
dc.subjectDissolved reactive phosphorus
dc.subjectPhosphorus
dc.subjectSubmerge
dc.titleRedox-induced phosphorus release from critical source areas following rainfall events in New Zealand
dc.typeJournal article
pubs.elements-id493292
pubs.organisational-groupOther
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