Occurrence of Athiorhodaceae in woodland, swamp, and pond soils

Tests (by enrichment culture) for nonsulfur purple photosynthetic bacteria in surface soils showed them in all of three sediment cores sampled in a shallow pond and in all of six peats from nearby swamp hollows beneath cedar and tamarack. They also occurred in two of three peats from swamp flats and three of five peats from swamp hummocks. For woodland and grassland surface soils, proportions were three out of seven and five out of nine sites respectively. For the total number of tubes inoculated at varying dilutions from each of these sites, the following proportions of positives were recorded: uppermost lake sediments 92%, swamp hollows 67%, swamp flats 38%, swamp hummocks 20%, woodlands 14%, grasslands 8%.