Studies onBeggiatoa: Distribution and growth in aquatic habitats of visakhapatnam

Abstract

Beggiatoa is distributed in 11 of the 12 polluted aquatic habitats occurring on the sediment and decaying leaves as a thick white scum at 2, in detectable population at 6, and in very less population at 3 habitats where H₂S necessary for its growth is produced. TheBeggiatoa spp. present in these habitats are considered as belonging to the 6 species described in Bergey’s manual.B. minima with less than 1·0,B. leptomitiformis with 1·66,B. alba with 3·32 and and 4·98 μ wide trichomes are distributed in 2, 6, 11 and 2 habitats respectively, which are fresh water, brackish and marine habitats.B. arachnoidea with 9·96,B. mirabilis with 17·0 andB. gigantea with 28·22 μ wide trichomes are present in only one brackish habitat.B. alba (3·32 μ) occurs alone at 2 habitats, and in association with either one or more of the otherBeggiatoa species at the remaining 9 habitats. ExceptB. mirabilis andB. gigantea, the others distributed in the 11 habitats could multiply in enrichment culture media that contained extracted rice straw pieces and waters from their respective habitats, and aggregate into visual white colonies, or loose clumps in a thick film on the surface of medium, rice straw pieces and glass.B. mirabilis andB. gigantea seem to be halophilic, truly autotrophic and more exacting than the other species that exhibited differences in salt tolerance when grown in crude enrichment culture media of differing, salt content. It appears that physiological strains or groups differing in salt tolerance may be existing in these species ofBeggiatoa.