Tritiated thymidine incorporation as a measure of microbial activity in lake sediments

Cell proliferation, determined by incorporation of tritiated thymidine into DNA, was used as a measure of microbial activity in lake sediments. Microbial activity in surface and sediment samples from Lake Erie was compared by this technique; activity was greatest in the surface 7 cm of core samples and geographically in a central basin core. The specificity, sensitivity, and low background inherent in the method make it suitable for routine estimates of microbial activity.