JellyWatch provides a platform to upload information and images of the jellyfish observed in your area or while traveling.
NASA Citizen Science offers a variety of projects that range from cloud spotting to planet hunting to exploring dark energy.
NOAA Citizen Science includes observation and real-time data collections for various projects including harmful algal blooms, whale watching, geocaching, tide tracking, and marine debris.
U.S. Forest Service provides access to various projects that can be searched by state and theme (e.g. urban, water, biodiversity, etc.).