Original paper

Rasterelektronenmikroskopische und kulturelle Untersuchungen zur mikrobiellen Besiedlung von Sandkörnern und Geröllen aus dem Grundwasserbereich

[Investigation of Microbial Colonization of Sand and Gravel from the Sphere of Groundwater by Scanning Electron Microscopy (SEM) and Cultural Methods]

Tuschewitzki, Georg-Joachim; Grubert, Lothar


Sand und Kies aus dem Grundwasserbereich wurden sowohl rasterelektronenmikroskopisch als auch kulturell hinsichtlich ihrer quantitativen und qualitativen mikrobiellen Besiedlung untersucht. Bei der rasterelektronenmikroskopischen Untersuchung zeigten die untersuchten Gerölle des Grundwasserleiters eine sehr rauhe und zerklüftete Oberfläche, auf der viel feines mineralisches Material abgelagert war. Mikroorganismen konnten hier trotz intensiven Suchens mit dem Rasterelektronenmikroskop nicht festgestellt werden. Die kulturelle Untersuchung ergab nach Abschütteln der Organismen eine Besiedlungsdichte von 102 bis 104 Mikroorganismen auf einem Gramm des Sand- und Kiesmaterials.


Sand and gravel from the sphere of groundwater had been analyzed for bacteria by scanning electron microscopy and cultures. SEM showed a very rough sand and gravel surface, partly covered by small mineral particles. No bacteria could be found on the surfaces using SEM. After addition of a 5 ml sterilized water and vigourous shaking of the material 102--104 bacteria/gramm were cultured on SPC agrarplates from two different samples. It is assumed that there is an inhomogenous distribution of bacteria in the groundwater and soil: near enrichment of organic material increased bacterial counts could be found. Within the material of each sample there was only a small difference in colony counts. The surface of the material was calculated to 850 cm2/g. This means that only 10--5 %--10--7 % of the whole surface is covered by microbial colonization. 121 bacterial strains from sand and gravel were isolated and further classified. 63 % from the first and 77 % from the second sample were gramnegative. The second sample was divided into 9 parts in which 3 of them actinomycetes were found. This showed qualitative differences in the bacterial colonization within few centimeters.


Scanning electron microscopymicrobial culturebiocenosesmicroorganismsaquifersandgravelquantitative analysis