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0 5 <br />production occurring in a community influencing rates of respiration. <br /> King and Ball (1967) found evidence that the level of net primary <br />. <br /> production of periphyton and macrophytes in lotic systems is con- <br /> trolled by the amount and kind of organic matter present. Using <br /> artificial streams, McIntire and Phinney (1965) found a strong p(asi- <br /> tive correlation between light intensity and gross primary production <br /> to a saturation point near 1,000 foot candles. Their work and that <br /> by Kevern and Ball (1965) also showed that above a saturation point <br /> of light water temperature is positively correlated with gross pro- <br /> duction of periphyton. Odum (1956) states that rates of production <br /> are greater in flowing (lotic) waters than in standing (lentic) <br /> waters. Production is also stimulated by nutrient concentration <br /> (Dugdale and Goering 1967, Whitford and Phillips 1959). <br /> Respiration rates have similarly been found to be positively <br /> correlated with water temperature by Phinney and McIntyre (1956) <br /> using artificial streams. Some evidence exists that insolation may <br /> also stimulate respiratory activity in primary producers (Thomas <br /> and O'Connell 1966). Whitford and Schumacher (1961, 1964) found <br /> respiration rates for Spirogyra and Oedogonium to be 56 per cent <br /> and 40 per cent higher, respectively, when grown in flowing waters <br /> (15 cm/sec and 250C) than cultures grown in standing water. <br /> Concentrations of imported dissolved and suspended organic materials <br /> can stimulate respiratory activities (Berman et al. 1977). <br /> The ratio of gross production to the rate of respiration <br /> (P/R) is commonly used to characterize aquatic communities with <br /> regard to trophic state. McIntire and Phinney (1965) found P/R <br />