Title of article :
Quantification of the impact of macrophytes on oxygen dynamics and nitrogen retention in a vegetated lowland river
Author/Authors :
Desmet، نويسنده , , N.J.S. and Van Belleghem، نويسنده , , S. and Seuntjens، نويسنده , , P. H. Bouma، نويسنده , , T.J. and Buis، نويسنده , , K. and Meire، نويسنده , , P.، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2011
Pages :
11
From page :
479
To page :
489
Abstract :
When macrophytes are growing in the river, the vegetation induces substantial changes to the water quality. Some effects are the result of direct interactions, such as photosynthetic activity or nutrient uptake, whereas others may be attributed to indirect effects of the water plants on hydrodynamics and river processes. This research focused on the direct effect of macrophytes on oxygen dynamics and nutrient cycling. Discharge, macrophyte biomass density, basic water quality, dissolved oxygen and nutrient concentrations were in situ monitored throughout the year in a lowland river (Nete catchment, Belgium). In addition, various processes were investigated in more detail in multiple ex situ experiments. eld and aquaria measurement results clearly demonstrated that aquatic plants can exert considerable impact on dissolved oxygen dynamics in a lowland river. When the river was dominated by macrophytes, dissolved oxygen concentrations varied from 5 to 10 mg l−1. Considering nutrient retention, it was shown that the investigated in-stream macrophytes could take up dissolved inorganic nitrogen (DIN) from the water column at rates of 33 – 50 mg N kg dry matter - 1 h - 1 . And DIN fluxes towards the vegetation were found to vary from 0.03 to 0.19 g N ha−1 h−1 in spring and summer. Compared to the measured changes in DIN load over the river stretch, it means that about 3–13% of the DIN retention could be attributed to direct nitrogen uptake from the water by macrophytes. Yet, the role of macrophytes in rivers should not be underrated as aquatic vegetation also exerts considerable indirect effects that may have a greater impact than the direct fixation of nutrients into the plant biomass.
Keywords :
River water quality , Macrophytes , Dissolved oxygen , nitrogen retention , Nutrient storage
Journal title :
Physics and Chemistry of the Earth
Serial Year :
2011
Journal title :
Physics and Chemistry of the Earth
Record number :
2302297
Link To Document :
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