Phragmites australis and silica cycling in tidal wetlands

Research output: Contribution to journalArticle

Abstract

Tidal marshes have recently been shown to be important biogenic Si recycling surfaces at the land-sea interface. The role of vegetation in this recycling process has not yet been quantified. In situ and ex situ decomposition experiments were conducted with Phragmites australis stems. In a freshwater tidal marsh, litterbags were incubated at different elevations and during both winter and summer. Biogenic Si (BSi) dissolution followed a double exponential decay model in the litterbags (from ca. 60 to 15 mg g(-1) after 133 days), irrespective of season. Si was removed much faster from the incubated plant material compared to N and C, resulting in steadily decreasing Si/N and Si/C ratios. Ex situ, decomposition experiments were conducted in estuarine water, treated with a broad-spectrum antibiotic, and compared to results from untreated incubations. The bacteria] influence on the dissolution of dissolved Si (DSi) from R australis stems was negligible. Although the rate constant for dissolved Si dissolution decreased from 0.004 to 0.003 h(-1), the eventual amount of BSi dissolved and saturation concentration in the incubation environment were similar in both treatments. P. australis contributes to and enhances dissolved Si recycling capacity of tidal marshes: in a reed-dominated small freshwater tidal marsh, more than 40% of DSi export was attributable to reed decomposition. As the relation between tidal marsh surface and secondary production in estuaries has been linked to marsh Si cycling capacity, this provides new insight in the ecological value of the common reed. (C) 2007 Elsevier B.V. All rights reserved.

Details

Authors
  • Eric Struyf
  • Stefan Van Damme
  • Britta Gribsholt
  • K. Bal
  • O. Beauchard
  • Jack J. Middelburg
  • Patrick Meire
Organisations
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Geology

Keywords

  • tidal marsh ecology, biogenic silica dissolution, Phragmites australis
Original languageEnglish
Pages (from-to)134-140
JournalAquatic Botany
Volume87
Issue number2
Publication statusPublished - 2007
Publication categoryResearch
Peer-reviewedYes