Macrophytes decomposition

Soley S (2010) Interaction between macrophytes and phytoplankton compartments for the uptake and decomposition of phosphorus compounds, the case of the Ebro river (NE Spain). Master thesis. University of Girona, Spain... 

Changes in fauna of a reservoir following use of paraquat for weed control are likely to be indirect effects caused by decomposition of angiosperms (Brooker and Edwards 1974). Planktonic invertebrates closely associated with aquatic macrophytes were either eliminated by paraquat or survived at lower densities for at least a year posttreatment analysis of fish stomachs showed dietary changes following weed control and reflected availability of many invertebrate species associated with aquatic plants (Brooker and Edwards 1974). 

Koop, K., Newell, R.C. and Lucas, M.I., 1982. Microbial regeneration of nutrients from the decomposition of macrophyte debris on the shore. Mar. Ecol. Prog. Ser., 9 91-96. 

FIGURE 3 Net generation of levulinic acid from the partial photolysis of sterile whole leachate (0.2 pm pore size filtrate) of the emergent macrophyte Juncus effusus (10 mg DOC L-1) after 4 weeks of microbial decomposition at 20°C in the dark. Exposed to full natural sunlight (total insolation over the 4 h period = 13.05 mol m 2 of UV-B, UV-A, and PAR), to PAR only, and incubated simultaneously in the dark. Error bars = SD n = 3 each. Modified from Wetzel, 2001. 

Aneiso, A.M., Abreu, B.A., and Biddanda, B.A. (2003) The role of free and attached microorganisms in the decomposition of estuarine macrophyte detritus. Estuar. Coastal Shelf Sci. 56, 197-201. 

Bianchi, T.S., and Findlay, S. (1991) Decomposition of Hudson estuary macrophytes photosynthetic pigment transformations and decay constants. Estuaries 14, 65-73. 

Rice, D.L., and Tenore, K.R. (1981) Dynamics of carbon and nitrogen during the decomposition of detritus derived from estuarine macrophytes. Estuar. Coastal Shelf Sci. 13, 681-690. 

If the chemical composition of the samples is known or at least partly known (in a stepwise TIE approach) or existing data allow for QSAR calculation, the samples can be ranked by TUs. Arts et al. (2006) studied, in 12 outdoor ditch mesocosms, the effects of sequential contamination with 5 pesticides in a regression design. They applied dosages equivalent with 0.2%, 1%, and 5% of the predicted environmental concentration (PEC) subsequently over 17 weeks. Endpoints recorded over 30 weeks included community composition of macroinvertebrates, plankton, and macrophytes, and leaf litter decomposition as functional ecosystem parameters. TUs were calculated in relation to acute toxicity data for the most sensitive standard species Daphnia magna and Lemna minor. Principal response curves (PRCs), a special form of constrained PCA, and Williams test (NOEC, class 2 LOEC) were used to identify the most sensitive taxa. Next to direct effects on certain species, also indirect effects, for example, how the change in abundance of a sensitive species affects the abundance of another, more tolerant species, can be detected only in mesocosm or in situ experiments. All observed effects were summarized in effect classes in a descriptive manner. 

Kuehn, K. A. Suberkropp, K. (1998a). Decomposition of standing litter of the freshwater macrophyte Juncus effusus L. Freshwater Biology, 40, 717-27. 

Kuehn, K. A., Gessner, M. O., Wetzel, R. G. Suberkropp, K. (1999). Standing litter decomposition of the emergent macrophyte Erianthus giganteus. Microbial Ecology, 38, 50-7. 

In addition to effects on DOM, UV exposure also impacts the decomposition of POC [120]. Photoproduction of DIC has been observed from the sterilized detritus of several aquatic macrophytes in both air and immersed in water [120]. The highest production rates were observed in water. Although UVR was most effective at inducing detritus decomposition, visible light also played a role. 

Because of the high residence time of standing dead tissue of emergent macrophytes such as Typha and Cladium, a signihcant degree of decomposition occurs by the time the leaf material enters the soil detrital layer. Leaching and mineralization of water-soluble, nonstructural components... 

FIGURE 5.38 Rate of decomposition of different carbon fractions from emergent macrophytes. (Adapted from Moran et al., 1989.)... 

Decomposition rate constants are negatively correlated to the total fiber content of the organic snbstrate bnt not well correlated to individual components such as cellulose, hemicellulose, and lignin. A field and laboratory study by Moran et al. (1989) measured the decomposition rates of whole litter and the lignocellulose components of the litter for the emergent macrophytes S. alterniflora and C. walteriana. Decomposition of individual carbon fractions varied with the rate of decomposition in the order of cellulose > hemicellulose > lignin (Figure 5.38, Moran et al., 1989). 

Chimney, M. J. and K. C. Pietro. 2006. Decomposition of macrophyte litter in a subtropical constructed wetland in south Florida (USA). Ecol. Eng. 27 301-321. 

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