Images

Researchers approach Blackfoot Glacier in Glacier National Park.

Pictographs at Saguaro National Park. Photographed 2006 or earlier

Clouds Overlying a Forest.

Photomicrograph depicting the siliceous frustules of fifty species of diatoms arranged within a circular shape. Diatoms form the base of many marine and aquatic food chains and upon death, their glassy frustules form sediments known as diatomaceous earth.

A Cascades frog perched on moss.

An unknown hybrid species of salamander captured in Olympic National Park, Washington.

Reseracher Maureen Ryan poses by a pond holding one of her study species, a cascades frog.

An unknown hybrid species of salamander captured in Olympic National Park, Washington.

USGS researchers Brome McCreary (orange vest) and Chris Pearl take measurements on Cascades frog at a mountain lake in Oregon.

Larval Pacific lamprey collected from the upper Umatilla River in northeastern Oregon.

Snakehead fish are originally from China and Korea, but recently they've been found in Maryland, Virginia, Arkansas, California, and Florida.

Snakehead fish are originally from China and Korea, but recently they've been found in Maryland, Virginia, Arkansas, California, and Florida.

Herring larvae 15 days post-hatch. Food in the gut appears orange.

Herring larvae 53 day post-hatch. Black pigmentation is evident.

Naturally-deposited herring eggs attached to submerged macrophytes. Coiled embryos are evident inside the eggs.

Small herring spawning event in Puget Sound, evidenced by the presence of 'white water', caused by mass release of spawning products into the water.

Elk traveling across winter range in the northwestern Greater Yellowstone Ecosystem near the Gardiner River in Yellowstone National Park, 2008.

The ice froze around the fence post, the stage in the river went up, then the river froze again, creating a large gage height correction - Heart River near Richardton, North Dakota.

The Agassiz's desert tortoise, a native of the Mojave Desert.

A pocketbook mussel (Lampsilis cardium). Native freshwater mussels are among the most fascinating, widespread, and endangered animals in fresh waters. They play important ecological roles in our lakes and rivers and their shells are used to produce cultured pearls.

This image of a live silver carp egg specimen was taken with a microscope camera at the USGS Columbia Environmental Research Center. Asian carp are invasive species that could pose substantial environmental risks and economic impacts if they become established.