Gram stain index of a natural bacterial community at a nutrient gradient in the freshwater environment

• Published in: Environmental pollution (1987) 2000-08, Vol.109 (2), p.293-301
• Main Authors: Saida, H., Maekawa, T., Satake, T., Higashi, Y., Seki, H.
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Bacteriological methods and techniques used in bacteriology; Bacteriology; Biological and medical sciences; Experimental nutrient gradient; Freshwater; Freshwater environment; Fundamental and applied biological sciences. Psychology; Gram stain index, GSI; In situ gradostat; Microbial ecology; Microbiology; Natural bacterial community; Species succession; Various environments (extraatmospheric space, air, water)
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/S0269-7491(99)00257-2

“Capsule”: Gram stain index suggested as an indicator of organic pollution in water. Species succession of a natural bacterial community was indicated by the Gram stain index (GSI) using an experimental nutrient gradient in an oligotrophic pond created with an in situ gradostat. Various trophic conditions, ranging from eutrophic to mesotrophic, were formed experimentally with continuous inflow of sterile peptone solution in the gradostat, while the water mass outside the gradostat was oligotrophic. The GSI spectra of the natural bacterial populations show different profiles in accordance with the trophic level of the ambient water and the time progression of adaptation to different levels of eutrophication. Therefore, GSI can be used as a potential indicator of organic pollution in aquatic environments.