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Seasonality and spatial variation in abundance, biomass and activity of heterotrophic bacterioplankton in relation to some biotic and abiotic variables in an Ethiopian rift‐valley lake (Awassa)
Author(s) -
GEBREMARIAM ZINABU,
TAYLOR WILLIAM D.
Publication year - 1989
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.1365-2427.1989.tb01110.x
Subject(s) - bacterioplankton , seasonality , abiotic component , stratification (seeds) , biomass (ecology) , plankton , ecology , phytoplankton , environmental science , hypolimnion , abundance (ecology) , heterotroph , biology , spatial variability , nutrient , eutrophication , bacteria , agronomy , genetics , germination , seed dormancy , dormancy , statistics , mathematics
SUMMARY. I. Seasonality and spatial variation in abundance, biomass and activity of heterotrophic bacterioplankton was studied in a tropical freshwater lake. Variation in phytoplankton biomass and production, and several other limnological parameters, were also quantified. 2. Bacterial number and biomass fluctuated between 3.88–8.33×10 6 ml −1 and 68–125 mg C m −3 , respectively. No spatial variation was observed in these bacterial variables, although other limnological parameters showed vertical variation. 3. Seasonal and vertical variation of heterotrophic bacterial activity were estimated from oxygen consumption, 14 CO 2 dark uptake and plate counts of colony forming units. All three methods showed vertical heterogeneity, with higher activity in the hypolimnion during the long stratification period (February May). Oxygen consumption rate and plate counts showed seasonality. 4. In spite of the low seasonality of climate in the tropics, several biological, chemical and physical variables were correlated with changes in bacterial variables. Wind and rainfall, and their effects on stratification and mixing, vertical distribution of nutrients and rate of primary production appeared to be the important parameters affecting heterotrophic bacterioplankton.