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Physiological ecology of heterotrophic bacteria in two Indiana lakes

Thesis/Dissertation ·
OSTI ID:5666642
Rates of bacterial production of particulate organic carbon in two hardwater Indiana lakes were studied. Primary production rates were calculated from rates of photosynthetic H/sup 14/CO/sub 3//sup -/ incorporation and bacterial (secondary) production from rates of /sup 3/H-(methyl)-thymidine incorporation by natural samples. The relationship of thymidine incorporation to rates of bacterial growth in diluted natural samples was used to calculate the conversion factor 2.2 x 10/sup 18/ cells produced (mole thymidine incorporated)/sup -1/. Bacteria in Little Crooked Lake were found to be growing at suboptimal temperatures throughout most of the water column, even during the summer months. Even rapidly growing metalimnetic populations displayed no noticable adaptation to low environmental temperatures. This indicates that temperature could have limited the growth of bacteria in this lake throughout the period of thermal stratification. The extracellular release of photosynthetically fixed organic carbon by healthy phytoplankton was not found to be an important carbon source for planktonic bacteria. Slow carbon release mechanisms, such as algal decomposition, seem to have been more important.
Research Organization:
Purdue Univ., Lafayette, IN (USA)
OSTI ID:
5666642
Country of Publication:
United States
Language:
English