Norbert Wu / Blue Rockfish (Sebastes mystinus) schools under kelp forest canopy, Monterey, California

Tim Fitzharris / Mount Rainier and Reflection Lake, Mount Rainier National Park, Washington

Fred Bavendam / West Indian Manatee (Trichechus manatus) eating Hydrilla (Hydrilla sp) an introduced plant that often clogs waterways, Blue Spring State Park, Florida

Tim Fitzharris / Boulders and mountain, Rocky Mountain National Park, Colorado

Tim Fitzharris / Zion Canyon and Virgin River, Zion National Park, Utah

Tim Fitzharris / Conifers in winter, Yellowstone National Park, Wyoming

Yva Momatiuk & John Eastcott / Calcium tufa formations, Mono Lake, California

Yva Momatiuk & John Eastcott / Sandstone hills along lake, Lake Powell, Glen Canyon National Recreation Area, Utah

Yva Momatiuk & John Eastcott / Sandstone formations deeply eroded by water, Spring Valley State Park, Nevada

Yva Momatiuk & John Eastcott / Joshua Tree (Yucca brevifolia) in desert, Eagle Valley Reservoir, Nevada

Yva Momatiuk & John Eastcott / Calcium tufa formations, Mono Lake, California

Yva Momatiuk & John Eastcott / Calcium tufa formations, Mono Lake, California