This high-magnification microscopic image shows yellow-stained bacteria, each one about 1 micrometer wide, colonizing sediment grains from the deep sea. Such images allow us to determine the number of bacteria in sediments (this sample has already been diluted 10,000-fold), but not which ones are active, since any intact cell containing DNA, whether it is active or dormant, will take up this stain. (Photo courtesy of Shelly Carpenter). |
