Diatoms, a golden brown algae, rule Earth's waterways. From Antarctica's glacial lakes to acidic hot springs to unkempt home aquariums, diatoms are everywhere. It's a good thing. The tiny creatures pump out up to 50 percent of the planet's oxygen, said Edward Theriot, a diatom expert and evolutionary biologist at the University of Texas at Austin, who was not involved in the study.
The algae look like little petri dishes or footballs, depending on the species, and spend most of their lives drifting on currents. How diatoms manage to colonize new homes remains a mystery: They can't swim.
Yet diatoms get around. When Wyoming's Yellowstone Lake emerged from its mile-thick ice cover 14,000 years ago, diatoms quickly arrived, Theriot said. "They had to be blown in by some mechanism or carried in by water birds," he added.
Diatoms particularly love volcanic lakes, because they are the only creatures that build shells of glass. (Glass sponges, for instance, produce a skeleton of glass spicules — tiny spike-like structures — but not a hard shell.) Silica-rich magma often causes the volcanic explosions that leave behind lake-filled craters, and silica is the key ingredient in diatom shells. Yellowstone Lake, which sits in a caldera created by a super-eruption, contains so many diatoms that the lake sediments are mostly shells (85 percent by weight), Theriot said.
Now scientists know what happens to diatoms when a massive volcano like Yellowstone blasts through a big lake.