least 20 million types of marine microbes (possibly a billion) make up 50–90 percent of the ocean’s biomass. The number of microbial cells in the water column, meaning sea surface to sea floor, is more than 10 to the 30th, a nonillion, or 1,000 × 1 billion × 1 billion × 1 billion. This is equal to the weight of 240 billion African elephants.
