GROWTH AND SURVIVAL OF TADPOLES (BUFO-AMERICANUS) FED AMORPHOUS DETRITUS DERIVED FROM NATURAL-WATERS

Growth and survival of tadpoles (Bufo americanus) were used to assess the food value of three types of amorphous detritus thought to be derived from dissolved organic matter (DOM) transported in river water or groundwater: 1. Flocculent organic aggregates suspended at the mouth of a humic stained river which drains into Lake Superior; 2. Precipitates formed directly from humic stained river water; 3. The < 35-mu-m fraction of littoral lake sediment. Tadpoles were unable to grow when fed the amorphous detritus, but experienced lower mortality than unfed animals. Although the food quality of certain types of detritus derived from DOM may be inadequate to support the growth of aquatic fine particle feeders it may contribute to the nutrition of facultative detritivores.