Lyngbya

Photograph by David Patterson, micro*scope

The ropelike coils of these filamentous cyanobacteria, found in a New England salt marsh, are created when many disc-shaped cells join end-to-end. Cyanobacteria, which use photosynthesis to produce oxygen, are the oldest known forms of life on Earth. They appeared in the fossil record over three billion years ago and laid the biological groundwork for today’s plants.