In situ, high-resolution imaging of labile phosphorus in sediments of a large eutrophic lake

Shiming Ding*, Chao Han, Yanping Wang, Lei Yao, Yan Wang, Di Xu, Qin Sun, Paul N. Williams, Chaosheng Zhang

*Corresponding author for this work

Research output: Contribution to journalArticle

149 Citations (Scopus)

Abstract

Understanding the labile status of phosphorus (P) in sediments is crucial for managing a eutrophic lake, but it is hindered by lacking in situ data particularly on a catchment scale. In this study, we for the first time characterized in situ labile P in sediments with the Zr-oxide diffusive gradients in thin films (Zr-oxide DGT) technique at a two-dimensional (2D), submillimeter resolution in a large eutrophic lake (Lake Taihu, China, with an area of 2338km2). The concentration of DGT-labile P in the sediment profiles showed strong variation mostly ranging from 0.01 to 0.35mgL-1 with a considerable number of hotspots. The horizontal heterogeneity index of labile P varied from 0.04 to 4.5. High values appeared at the depths of 0-30mm, likely reflecting an active layer of labile P under the sediment-water interface (SWI). Concentration gradients of labile P were observed from the high-resolution 1D DGT profiles in both the sediment and overlying water layers close to the SWI. The apparent diffusion flux of P across the SWI was calculated between -21 and 65ngcm-2d-1, which showed that the sediments tended to be a source and sink of overlying water P in the algal- and macrophyte-dominated regions, respectively. The DGT-labile P in the 0-30mm active layer showed a better correlation with overlying water P than the labile P measured by ex situ chemical extraction methods. It implies that in situ, high-resolution profiling of labile P with DGT is a more reliable approach and will significantly extend our ability in in situ monitoring of the labile status of P in sediments in the field.

Original languageEnglish
Pages (from-to)100-109
Number of pages10
JournalWater Research
Volume74
Early online date13 Feb 2015
DOIs
Publication statusPublished - 01 May 2015

Keywords

  • Eutrophication
  • High resolution
  • Phosphorus
  • Sediment-water interface
  • Zr-oxide DGT

ASJC Scopus subject areas

  • Water Science and Technology
  • Waste Management and Disposal
  • Pollution
  • Ecological Modelling

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