USGS biologists and hydrologists are investigating the causes for the declined of the western toad (Bufo boreas) in Pacific Northwest states. One suspected cause of the decline is a fungal infection caused by the chytrid fungus Batrachochytrium dendrobatidis.

USGS scientists and their colleagues have developed a method to detect the presence of Batrachochytrium dendrobatidis DNA in water and sediment. For water, the method involves pumping water and collecting particulate matter on a filter for later analysis. Shown above is the pump USGS scientists use to flow stream water through a small cartridge filter before collecting the water in a sample bottle. The water body in the background is Fernridge Reservoir, Oregon.

A USGS scientist has a visit from a small Columbia spotted frog (Rana luteiventris). The scientist is pumping stream water and filtering out particulates. The filtered sample is part of an effort to detect Batrachochytrium dendrobatidis (Bd) DNA in the environment. The data gathered is being used to develop a better understanding of the relationship between the environmental occurrence of Bd and the incidence of chytridiomycosis (a fungal infection) in amphibians.

Sitting on the banks of Spruce Lake in Rocky Mountain National Park, Colorado, this USGS scientist is using a cordless drill to power a water pump. The pump is pumping stream water through a small cartridge filter. Trapped on the filter are various particulates from a lakeside marsh, which include very small quantities of DNA. Using advanced molecular methods a team of scientists will analyze the sample for the presence of the DNA from a fungus (Batrachochytrium dendrobatidis) linked to a fungal infection (chytridiomycosis) that can kill amphibians.

This small cartridge filter contains particulates collected from a wetland near Beaverton, Oregon. DNA will be extracted from the filter and amplified by a laboratory technique called polymerase chain reaction (PCR). PCR uses enzymes called polymerases to make multiple copies of specific fragments of DNA with the objective of creating enough DNA material to analyze. PCR gives scientists the ability to detect the DNA of specific organisms even when their abundance is low in the environment.

A USGS scientist bagging up a sample collected from a remote site in Rocky Mountain National Park, Colorado. The sample will be analyzed by a new method that detects the presence of the chytrid fungus Batrachochytrium dendrobatidis (Bd) in water and sediment. The new method gives scientists a tool to help study the environmental conditions under which Bd becomes infectious, and the mechanisms by which it spreads from one place to another.

USGS scientists collecting a water-quality sample from Loma Verde Wash in Saguaro National Park, Arizona, as part of the USGS's Amphibian Research and Monitoring Initiative. Hydrologists and herpetologists are collaborating to understand the causes of amphibian declines and malformations. Hydrologists are providing expertise on the hydrology and water quality of study areas, and information on hydrologic and water-quality factors that may be impacting amphibian populations.

USGS scientist collecting a water-quality sample from the Okefenokee Swamp, GA (circa 2002) that will be analyzed for nutrients and alkalinity.

Preparing a water-quality meter to measure field parameters (pH, temperature, dissolved oxygen, and specific conductance) of waters in the Okefenokee Swamp, GA (circa 2002).

USGS technicians installing a pressure transducer in a pond in the Saint Marks National Wildlife Refuge, FL (circa 2004). Hydraulic data provides the framework for the analysis of amphibian population data.

USGS scientists checking under a cover board for amphibians and collecting a water sample to analyze the acid-neutralizing capacity (ANC) of the water from the adjacent vernal pool, Rock Creek National Park, Washington, DC (circa 2002).

USGS scientist collecting a water sample from a pond in Rocky Mountain National Park, CO (circa 2000) to answer questions about the effect of contaminants on amphibian populations.