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The distribution of some freshwater planktonic bacteria in two stratified eutrophic lakes
Author(s) -
JONES J. G.
Publication year - 1978
Publication title -
freshwater biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 156
eISSN - 1365-2427
pISSN - 0046-5070
DOI - 10.1111/j.1365-2427.1978.tb01435.x
Subject(s) - hypolimnion , thermocline , biology , anoxic waters , bacteria , eutrophication , plankton , epilimnion , ecology , zoology , environmental chemistry , chemistry , nutrient , genetics
SUMMARY. Changes in bacterial populations and certain physical and chemical variables in Esthwaite Water between June and September 1975 were studied and compared with results obtained from 1972 to 1974 in the hypolimnia of Blelham Tarn and the Lund tubes. The counts of total bacteria ranged between 1 and 7 × 10 6 ml −1 and were highest in the anoxic hypolimnion. The bacterial genera examined in more detail constituted only a small percentage of this count and included Ochrobium (10 4 ml −1 ), Naumanniella (10 3 ml −1 ), Leptothrix (10 2 ml −1 ), Planctomyces (10 3 ml −1 ), and Metallogenium (10 2 ml −1 ). The iron bacteria appear to grow best in the oxycline where there was not only sufficient oxygen for aerobic growth but also a plentiful supply of reduced iron. Planctomyces numbers increased as the thermocline became depressed in September. The results from Blelham Tarn might be interpreted as further evidence of growth by iron bacteria in the absence of dissolved oxygen, but other explanations are possible. Examination of the results by multiple regression analysis showed that it was possible to explain a significant proportion of the bacterial variation (with the notable exception of the Planctomyces counts) in spite of considerable intercorrelation of the regressor variables.