Macrophytes oxygen

Allelochemic effects of aquatic macrophytes on algae are discussed. Bloassays of chromatographic fractions from Eleocharls mlcrocarpa Torr. Indicate that oxygenated fatty acids are the causative agents. Methods of Isolation of these materials from aquatic macrophytes and from natural waters are described. Purification and structure determinations show that prominent components of the fraction are C q tri-hydroxycydopentyl and hydroxycydopentenone... 

Kemp, W. M., and Murray, L. (1986). Oxygen release from roots of the submersed macrophyte, Potamogeton perfoliatus L. Regulating factors and ecological implications. Aquat. Bot. 26, 271—283. 

Sand-Jensen, K., Prahl, C., and Stockholm, H. (1982). Oxygen release from roots of submerged aquatic macrophytes. Oikos 38, 349—354. 

Calhoun A. and King G. M. (1997) Regulation of root-associated methanotrophy by oxygen availabihty in the rhizosphere of two aquatic macrophytes. Appl. Envirort Microbiol 63, 3051-3058. 

Oxidation of As(III) to As(V) by microorganisms using oxygen as the terminal electron acceptor has been reported in laboratory cultures (Osborne and Ehrlich, 1976 Phillips and Taylor, 1976). This process has also been observed in natural settings. Wilkie and Hering (1996) found that As(III) from geothermal sources entering a stream was rapidly oxidized to As(V) by bacterial colonies associated with macrophytes. 

Clu istensen, P. B., Revsbech, N. P.. and Sand-Jensen, K. (1994). Microsensor analysis of oxygen in the rhizosphere of the aquatic macrophyte Littorella uniflora (L.) Ascherson. Plant Physiol. 105. 847-852. 

Smits, A. J. M., Laan, P., Thier, R. H., and van der Velde, G. (1990). Root aerenchyma, oxygen leakage patterns and alcoholic fermentation ability of the roots of some nymphaeid and isoetid macrophytes in relation to the sediment type of their habitat. Aquatic. Botany. 38, 3 — 17. 

Traditionally, lake monitoring has focused on physico-chemical parameters (nutrients, oxygen profiles, etc.) and on phytoplankton biomass as indicated by chlorophyll a, on which several classification schemes exist (e.g. OECD, 1982 Cailson, 1977). Only recently, following the new requirement introduced by the WFD to assess lake ecological status (see Cardoso et al., 2006 for a review) have most European countries included several other biological quality elements in their routine monitoring programmes, such as phytoplankton, macrophytes and phytobenthos, benthic invertebrates and fish. 

Brix, H., 1993. Macrophyte-mediated oxygen transfer in wetlands Transport mechanisms and rates. In Moshiri, G.A. (Ed.), Constructed Wetland for Water Quality Improvement,... 

Estuaries are typically heterotrophic systems, which means that the amount of organic matter respired within the estuary exceeds the amount of organic matter fixed by primary producers (phytoplankton and macrophytes). Since production of carbon dioxide then exceeds biological removal of carbon dioxide, it follows that estuaries are likely to be sources of the gas to the atmosphere. At the same time, since oxidation of organic matter to CO2 requires oxygen, the heterotrophic nature of estuaries suggests that they represent sinks for atmospheric oxygen. In many estuaries, primary productivity is severely... 

Oxygen supply in wetlands is restricted to the water column and to a thin layer of surface soil. Oxygen is also transported by wetland macrophytes to their root zone, resulting in the creation of aerobic conditions on root snrfaces (see Chapters 3 and 6 for a detailed discussion on aerobic-anaerobic interfaces in wetlands). 

Several factors influence the thickness of an oxidized surface layer. These include the oxygen concentration of the floodwater, the soil organic matter content, the amount of reduced compounds in the reduced or anaerobic soil zone, the photosynthetic activity of periphyton and aquatic macrophytes, and the bioturbation by macroorganisms. 

Evidence of BOD removal due to oxygen transport by floating and emergent macrophytes is presented by Reddy et al. (1990). Oxygen transport by plants resulted in BOD removal rates of... 

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