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Plankton decomposition

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). [Pg.1170]

Titanium dioxide is a well-known powerful photocatalyst for decomposing a wide range of substances, including inorganic compounds [276-279], organic compounds including 2-propanol and methylene blue [280-292], and microorganisms such as bacteria and plankton [293-296] and decomposition of NOx in ambient air [297],... [Pg.448]

Laboratory experiments on the decomposition of plankton under aerobic and anaerobic conditions showed that the mineralization of organic matter is practically halted under anaerobic conditions which prevail in the bottom sediments (I, 29). [Pg.49]

Experiments dealing with the decomposition of plankton and the regeneration of nutrients in vitro and under laboratory conditions have been performed. Von Brand and Rakestraw (24, 25, 26, 27, 28) reported the process... [Pg.49]

The relationships between the ratios of Org. C/Org. N mentioned above indicate that the organic nitrogen in plankton is subjected more intensively to microbiological decomposition processes than organic carbon in the course of their sinking in lake water and also soon after they settled on the bottom surface. [Pg.62]

Gajewski, A. J., and R. J. Chrost. 1995. Production and enzymatic decomposition of organic matter by microplankton in a eutrophic lake. Journal of Plankton Research 17 709—728. [Pg.20]

Vrba, J., J. Nedoma, K. Simek, and J. Seda. 1992. Microbial decomposition of polymeric organic matter related to plankton development in a reservoir Activity of a, 3-glucosidase, and P-N-acetlyglucosaminidase and uptake of N-acetylglucoseamine. Archiv fitr Elydrobiologie 126 193-211. [Pg.342]

Ehrenhauss, S., and Huettel, M. (2004) Advective transport and decomposition of chain-forming planktonic diatoms in permeable sediments. J. Sea Res. 52, 179-198. [Pg.576]

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. [Pg.152]

Skopintsev, B.A., 1949. On the rate of decomposition of the organic matter of dead plankton. Trudy Vses. [Pg.301]

Urea ((NH2)2CO) is excreted by larger organisms, can be a product of bacterial organic matter decomposition, and is a highly labile form of N for plankton nutrition (Bronk, 2002). Reports of concentrations in oceanic waters are relatively scarce, but are quite low (<0.5 pM Antia et al, 1991). There are currently two methods commonly used to measure urea concentrations—the urease method (McCarthy, 1970) and the monoxime method (Mulvenna and Savidge, 1992 Price and Harrison, 1987). [Pg.1228]

Once in the photic zone, P is readily incorporated into biogenic particles via the photo synthetic activity of plankton and begins to sink. The majority of these particles decompose in the surface waters or in shallow layers of sediments and the P is recycled directly back into the photic zone to be incorporated into biological particles. A small part of these particles escapes the surface layer and sinks into the deep ocean. Most of these particles eventually decompose and the cycle is repeated. Only a very small faction of these particles may incorporate into sediment without decomposition. [Pg.130]

Rutten mentions the old argument that, because the bulk of photosynthesis is thought to come from oceanic plankton, it is not certain whether the flora of the Carboniferous really produced a measurable excess of oxygen. This argument is wrong the important parameter is not absolute productivity, but burial. The complete decomposition of plankton means that far less carbon is buried at sea compared with the situation on land, where plants are more refractory to decomposition. [Pg.78]

Comparative studies of the relation between primary productivity and benthic mineralization processes (Jahnke et al. 1990 Rowe et al. 1994 Hensen et al. 2000) show, however, that these empirical formulations are restricted to a limited, regional use (cf Section 12.3). A further important factor in this regard is the reaction stoichiometry of organic matter degradation, since it determines the proportional release of CO, NO and PO. Based on planktonic decomposition studies. [Pg.209]

However, the process which was observed in the water column was rapid metabolism of plankton stenols and stanols in the oxic zone above the O2/H2S interface. It appears from these results that decomposition reactions occur much faster than the stenol to stanol reduction in the water column of the Black Sea or Walvis Bay. Alternatively, proposed intermediates (4) and (5) in the conversion of stenols to stanols (Fig. 2) may be attacked and transformed by other processes in the water column. [Pg.102]

DECOMPOSITION OF ORGANIC MATTER OF PLANKTON, HUMIFICATION AND HYDROLYSIS... [Pg.125]

Using eqs. 1 and 2, and having exchanged D for N and P, in the experiment where decomposition of planktonic OM was controlled according to the accumulation of NH and PO4", rate constants for ammonification and phosphatization were determined (Skopintsev, 1938). The following equations may be of practical value in such calculations ... [Pg.126]

Conclusions. The processes and the rates of decomposition of OM of marine and fresh phytoplankton in the sea and in fresh water are virtually identical. Temperature changes considerably influence the rate of decomposition. The amount of the dissolved OM in water tends to increase towards the end of the experiment. This is, probably, a refractory OM or water humus of planktonic origin. The remaining non-degradable particulate OM (detritus) also shows a relatively h h stability. [Pg.131]


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See also in sourсe #XX -- [ Pg.131 , Pg.132 , Pg.134 , Pg.135 ]




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