ibclogo XVI International Botanical Congess


Abstract Number: 6202
Poster No. = 2593


VEGETATION MEDIATED IMPORT OF OXYGEN INTO WATER-SATURATED SOIL OF CONSTRUCTED WETLANDS FOR WATER QUALITY IMPROVEMENTS


Wu Zhenbin, He Feng, Cheng Shuiping & Marcus Darwent*, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072 China, *School of Life Science, University of Hull, Hull, HU6 7RX, U.K


One important role of the macrophytes in the downfow-upflow-circulation seminatural constructed wetlands water-treatment plots is to supply oxygen to the heterotrophic microorganisms in the rhizosphere. The presence of oxygen and the root substrate establish and support a diverse microflora of aerobic bacteria. This study evaluates the quantity of oxygen release from the constituent plant roots. Five species were selected from the systems. Except the highest oxygen release between 2-4 cm (mean 8 x 10-8 g cm _2 min _1) from the apex of Zizania caduciflora root, other species had the highest oxygen release (mean 18.5, 5, 12, 13 x 10-8 g O2 cm-2 cm _1 for Acorus calamus, Eichhornia crassipes, Sagitarria trifolia and Typha angustifolia, respectively) at the apex of the roots. Oxygen flux diminished with distance from the tip, and the flux was negligible and probably non-existent near to the root base.


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