Macrophyte

Problems associated with excessive levels of nutrients and unwanted nuisance species have already been mentioned. There are cases in which intentional fertilization is used by aquaculturists in order to produce desirable types of natural food for the species under culture. Examples of this approach include inorganic fertilizer appHcations in ponds to promote phytoplankton and zooplankton blooms that provide food for young fish such as channel catfish, the development of algal mats through fertilization of milkfish ponds, and the use of organic fertilizers (from Hvestock and human excrement) in Chinese carp ponds to encourage the growth of phytoplankton, macrophytes, and benthic invertebrates. In the latter instance, various species of carp with different food habits are stocked to ensure that all of the types of natural foods produced as a result of fertilization are consumed. 

There is a further complication in shallow lakes containing macrophytes (aquatic flowering plants, pteridophytes, and macroalgae). These take up and accumulate nutrients from the water and from the aquatic soil in which they are rooted (sediment). Although these plants are sometimes classed as nuisance weeds, they nevertheless act as an important alternative sink for nutrients which are denied to the plankton. In recent times, a key role of macrophytes in the successful and sustained management of water quality has been identified and explained. ... 

BCF factors in fish ranging from 1.08 to 1.85, indicating that bioconcentration of methyl parathion is not an important fate process (Crossland and Bennett 1984). In another study, methyl parathion was added to the water of a carp-rearing pond and the concentration of methyl parathion was measured in water, soil, macrophytes, and carp over a 35-day period. Results showed that methyl parathion accumulated in macrophytes for 1 day and in carp for 3 days following exposure, and then dissipated. The concentrations of methyl parathion decreased in macrophytes by 94% by day 35 and by 98% in carp tissue by day 28 (Sabharwal and Belsare 1986). These data indicate the potential for biomagnification in the food chain is likely to be low because methyl parathion appears to be metabolized in aquatic organisms. 

Rich JJ, GM King (1998) Carbon monoxide oxidation by bacteria associated with the roots of freshwater macrophytes. Appl Environ Microbiol 64 4939-4943. 

The response of marine macrophytes on oil dispersion is dependent on the type of both oil and oil dispersant [292]. Germination inhibition of the marine macrophyte Phyllospora comosa was used to assess and compare the effects of oil dispersants and dispersed diesel fuel and crude oil combinations. The inhibition of germination by the water-soluble fraction of diesel fuel increased after adding all dispersants investigated. This contrasted with crude oil, in which the addition of some dispersants resulted in an enhanced germination rate. 

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... 

The basic classification of CWs is based on the type of flow regime and macrophytic growth. In general terms, two types can be described (Figure 10.3). The selection of the most appropriate option shall be according to various operational factors and to the plants available in the region of... 

Current reviews on biosorption are related to general approaches90-93 to diverse types of biomass such as microbial biomass, plant wastes, and agro-based waste materials, or to a specific metal.4-94-98 However, a review on metal biosorption using macrophytes biomass is not available. In this chapter, a review on the current knowledge of biosorption using preferentially nonliving biomass from aquatic plants is presented. 

Recent reports on biosorbents based on diverse types of macrophytes are found widely in the literature. Free-floating aquatic plants from the genera Salvinia, Azolla, Eichhornia, Lemna, and Pistia have been described the most. S. natans biomass was able to uptake As(V) at low initial concentrations from 0.25 to 2 mg/L (74.8% and 54%, respectively). The experimental data fitted well to both Langmuir and Freundlich isotherms. The effect of pH and biomass quantities on sorption rate has also been investigated along with some metabolic parameters.105... 

Spirodela intermedia, L. minor, and P. stratiotes were able to remove Pb(II), Cd(II), Ni(II), Cu(II), and Zn(II), although the two former ions were removed more efficiently. Data fitted the Langmuir model only for Ni and Cd, but the Freundlich isotherm for all metals tested. The adsorption capacity values (K ) showed that Pb was the metal more efficiently removed from water solution (166.49 and 447.95 mg/g for S. intermedia and L. minor, respectively). The adsorption process for the three species studied followed first-order kinetics. The mechanism involved in biosorption resulted in an ion-exchange process between monovalent metals as counterions present in the macrophytes biomass and heavy metal ions and protons taken up from water.112... 

Hu, M.H., Ao, Y.S., Yang, X.E., and Li, T.Q., Treating eutrophic water for nutrient reduction using an aquatic macrophyte (Ipomoea aquatica Forsskal) in a deep flow technique system, Agricultural Water Management, 95, 607-615, 2008. 

Greenway, M., The role of macrophytes in nutrient removal using constructed wetlands, in Environmental Bioremediation Technologies, Singh, S.N. and Tripathi, R.D., Eds, Springer, Berlin, Heidelberg,... 

Miretzky, P., Saralegui, A., and Fernandez Cirelli, A., Aquatic macrophytes potential for the simultaneous removal of heavy metals (Buenos Aires, Argentina), Chemosphere, 57 (8), 997-1005, 2004. 

Choi, J.H., Park, S.S., and Jaffe, P.R., The effect of emergent macrophytes on the dynamics of sulfur species and trace metals in wetland sediments, Environmental Pollution, 140, 286-293, 2006. 

Rai, P.K., Phytoremediation of Hg and Cd from industrial effluents using an aquatic free floating macrophyte Azolla Pinnata, International Journal of Phytoremediation, 10, 430-439, 2008b. 

Mishra, V.K., Upadhyaya, A.R., Pandey, S.K., and Tripathi, B.D., Heavy metal pollution induced due to coal mining effluent on surrounding aquatic ecosystem and its management through naturally occurring aquatic macrophytes, Bioresource Technology, 99 (5), 930-936, 2008. 

Nahlik, A.M. and Mitsch, W. J., Tropical treatment wetlands dominated by free-floating macrophytes for water quality improvement in Costa Rica, Ecological Engineering, 28, 246-257, 2006. 

Verma, V.K., Tewari, S., and Rai, J.P.N., Ion exchange during heavy metal bio-sorption from aqueous solution by dried biomass of macrophytes, Bioresource Technology, 99 (6), 1932-1938, 2008. 

Guimaraes, J.R.D., Meili, M., Hylander, L.D., Castro e Silva, E., Roulet, M., Mauro, J.B.N., and Lemos, R.M.A., Mercury net methylation in five tropical flood plain regions of Brazil High in the root zone of floating macrophyte mats but low in surface sediments and flooded soils, Science of the Total Environment, 261 (1-3), 99-107, 2000. 

McIntosh A.W., Shephard B.K., Mayes R.A., Atchison G.J., Nelson D.W. Some aspects of sediment distribution and macrophyte cycling of heavy metals in a contaminated lake. JEnvironQual 1978 7 301-305. 

I. The source of allelochemicals The allelochemicals found in the water are produced by phycoplanktonic or bentonic algae, by aquatic macrophytes cohabiting with the algae, or are they present in the water body accidentally (They can be released by plants living on the border of the water body or by leakage water etc.)... 

The occurrence of toxic compounds in plant tissues is not necessarily related to allelopathy. Allelopathy should be evidenced through experiments in which a toxic product is shown to be released from the putative aggressor, and arrives at the putative victim in functional concentrations under reasonably natural conditions (Inderjit and Callaway 2003). First of all, laboratory experiments dealing with allelopathy should demonstrate the release of a compound in the medium. Two methods to collect allelchemicals released by laboratory cultures of macrophyte or microalgae are described in Sections 5 and 6. 

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