Images

Freshwater flowing over the Faka Union Canal Weir #1 near Port of the Islands, Collier County, Florida. During cold weather, freshwater flows here can maintain a downstream salinity gradient that creates a warm water refuge for manatees.

A manatee swims downstream from a weir in Faka Union Canal known to create a strong salinity gradient downstream.

This aerial view shows how Faka Union Canal (visible as a straight channel of water) connects the coastal environment, where manatees feed, to freshwater inlets. The Ten Thousand Islands region in the foreground supports sea grass beds where manatees feed.

A manatee feeds on sea grass beds in Ten Thousand Islands region of Florida.

Image of the silica cell wall of the diatom 'Didymosphenia geminata' from Rio Espolon, Chile. The sample was collected early in 2010 from an extensive bloom on the river. The image has been processed to show the silica cell wall, removing the organic cell contents and the stalk
material.

Bighead carp are a large and troublesome invasive species from Asia found in the great rivers of the central United States.

Bighead carp are a large and troublesome invasive species from Asia found in the great rivers of the central United States.

Silver carp are a large a troublesome invasive species from Asia found in the great rivers of the central United States. Silver carp have been observed to jump in response to rocks thrown in the water, passing trains, geese taking off from the water, or just when they unexpectedly find themselves in a tight place.

Bighead carp are a large and troublesome invasive species from Asia found in the great rivers of the central United States.

Bighead carp are a large and troublesome invasive species from Asia found in the great rivers of the central United States.

After being caught by mist nets, birds are anesthetized while a small transmitter is inserted into the abdominal cavity. The surgical procedure takes less than 30 minutes. Birds recover quickly and are ready for release within an hour of surgery. This photo shows a male curlew with a black leg flag inscribed "H8".

The Long-billed Curlew (Numenius americanus) is the largest North American shorebird and is characterized by its long and decurved bill.

A Devils Hole pupfish swims above the algae mat that typically covers the shallow spawning shelf in Devils Hole. 

USGS Cooperative Research Unit graduate student Ambre Chaudoin monitors pupfish spawning behavior in Devils Hole, the only habitat for endangered Devils Hole pupfish.The USGS cameras that captured effects of an earthquake on Devils Hole can be seen in this picture.

USGS Sirenia Project researchers studying manatees in Florida.

USGS biologist Randy Bennett and volunteers sample a stream using electro-fishing gear.

A prairie wetland at Ordway Prairie near Aberdeen, South Dakota.

A northern pintail duck wearing a transmitter.

A male northern pintail duck.

A male northern pintail duck in Japan.

Chicks and eggs of piping plovers. The piping plover is a small migratory shorebird listed as endangered in Canada and the U.S. Great Lakes, and threatened throughout the remainder of its U.S. breeding and winter range.