Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock () or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
Scanning Electron Microscope (SEM) image of the silicified microbial mats that form Castle Geyser. USGS image by Dakota Churchill.
Public Domain.
