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P <br />7 <br /> levels of exported organic matter are indicative of an autotrophic <br /> "producer" community. Conversely, where export decreases due to <br /> <br /> higher respiration activities, a heterotrophic "processor" community <br /> exists. Minshall (1978) found exported organic materials of a low <br /> order autotrophic stream to exceed imports. Fisher and Likens <br /> <br /> (1973) showed that in a heterotrophic stream where 99 percent of all <br /> organic energy in the system is allochthonous (imported) only 66 <br /> percent was exported. <br />. <br /> Dissolved organic compounds have been shown to affect algal <br /> productivity. Cummins (1974) states that diatoms should be considered <br /> facultative consumers of dissolved organic matter (DOM) as they are <br /> <br /> often found covered by particulate organic matter yet in a viable <br /> condition. Berman et al. (1977) found that a reduction in nitrate <br /> or ortho-phosphorous concentrations stimulated the uptake and <br /> <br /> respiration of dissolved organic compounds by algaes. They also <br /> suggested that DOM may stimulate algal production under low light <br />. intensities. Chemical oxygen demand (COD) is an accurate measure <br /> of the concentration of oxidizable organic matter in a system when <br /> toxic chemicals are not present (APHA 1975). This approach has <br />1 been used by Wilhm and Dorris (1966), Minshall (1967), and others <br /> to evaluate the dynamics of DOM in systems. <br />Some studies of aquatic macroinvertebrates have been done which <br />addressed longitudinal changes in community structure. Harrell <br />and Dofris (1968) found numbers of species and species diversity to <br />increase through fifth order streams and decline in higher order <br />Oklahoma streams. Wilhm and Dorris (1966) found distinct seasonal <br />0