Phragmites australis and Si recycling in freshwater tidal marshes
Struyf, E. (2005). Phragmites australis and Si recycling in freshwater tidal marshes, in: Struyf, E. The role of freshwater marshes in estuarine silica cycling (Scheldt estuary) = De rol van zoetwaterschorren in de estuariene siliciumcyclus (Schelde-estuarium). pp. 123-138 In: Struyf, E. (2005). The role of freshwater marshes in estuarine silica cycling (Scheldt estuary) = De rol van zoetwaterschorren in de estuariene siliciumcyclus (Schelde-estuarium). PhD Thesis. Universiteit Antwerpen: Antwerpen. 162 pp., more |
| Keywords | Water bodies > Inland waters > Wetlands > Marshes
Phragmites australis (Cav.) Trin. ex Steud. [WoRMS]
Belgium, Schelde R. [Marine Regions]
Marine/Coastal; Fresh water |
| Abstract | 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 in both winter and summer. No significant difference in biogenic Si dissolution at different tidal heights was observed. Both in winter and summer, biogenic Si concentrations decreased according to a double exponential decay model in the litterbags (from ca. 60 mg g-I to ca. 15 mg g-I after 133 days). Si was removed much faster from the incubated plant material compared to Nand C, resulting in steadily decreasing Si/N (from 7 to 2) and Si/C ratio's (from 0.15 to 0.03) in the litterbags in both winter and summer. Ex situ, decomposition experiments were conducted in Scheldt water, treated with a broad-spectrum antibiotic, and compared to results from untreated incubations. The bacterial influence on the dissolution of dissolved Si from stems was only minor: the rate constant for dissolved Si dissolution decreased from 0.004 h-I to 0.003 h-I, but eventual amount of BSi dissolved and saturation concentration in the incubation environment were similar in both untreated and treated experiments.Phragmites australis enhances dissolved Si recycling capacity of tidal marshes: in reed-dominated freshwater tidal marshes, more than 40% of DSi export was observed to be attributed to reed decomposition |
|
