In the eerie bluish-purple depths of an Antarctic lake, scientists have discovered otherworldly mounds that tell tales of the planet’s early days.
Bacteria slowly built the mounds, known as stromatolites, layer by layer on the lake bottom. The lumps, which look like oversized traffic cones, resemble similar structures that first appeared billions of years ago and remain in fossil form as one of the oldest widespread records of ancient life. The Antarctic discovery could thus help scientists better understand the conditions under which primitive life-forms thrived. “It’s like going back to early Earth,” says Dawn Sumner, a geobiologist at the University of California, Davis.