Hidrológiai Közlöny 1991 (71. évfolyam)

2. szám - Hegedűs János: A bakterioplankton lebontási erősségének vizsgálata alfa-amiláz aktivitás révén

HEGEDŰS J.: A bakterioplankton vizsgálata 85 The decomposition capacity of bacteriplankton determined in terins of alplm-aminase activity Hegedűs, J. Abstract: The results of studies 011 the decomposition capacity of the bacteriplankton in the Danube are described. Tlie experiments were made on samples taken from the Budapest stretch of t.lie Danube — R. Sts. L (>56—1631 km —- in 1986, using the following method. A 100 ml volume of the sample was passed tlirough a 0.46 fim pore size membrane filter, wliich was then földed with a pair of pincers and placed into a 1 ml Widal test tűbe containing the culture fluid, a 0.6% starch solution. An inoculation needle with the end bent to 90° was used to pusli the földed membrane into the culture fluid, so that it became fuilv immersed. The incubation period was 24 hours at 20—22 deg. C. The decomposition capacity was determined in natural and artifical light — the penetrating light from a normál bulb — taking the reading after the addition of 0.004 ml Lugol solution with reference to a seven degree colour scale. According to the activities determined the samples were classified into the quality classes I to IV normally used in water authority practice here. Pollution was found to be lowest upstream of Budapest (R. St. 1656 km), highest along the capital (R. Sts. 1048—1644 km), white the decreasing values downstream of the capital (R. St. 1631) reflected the intense decompositio and consumption activity. The water temperature was found to influence the species and quantity composition of the bacterioplankton. At water temperatures higher than 11.5 deg. C the bacterioplankton decomposed consistently first the amylose then the amylopectin of the two components. When the water temperature dropped below 11.5 deg. C, the bacterioplankton of changed species composition decomposed the amylopectin with higher intensity, but this was not as consistent as the primary decompositin of the amylose. The method developed by the author which requires extremely simple equipment, a few and inexpensive chemicals only, involves simple operations of inoculation and evaluation, is proposed for determining the decomposition activity of the bacterioplankton in surface waters. Keywords: Bacterioplankton, starch, amylose, amylopectin, alpha-amylase activity, decomposition capacity, temperature HEGEDŰS JÁX0S Szakmai munkásságának összefoglalóját a Hidrológiai Közlöny 1989. évi 5. számának 293. oldalán közöltük.