Chesapeake Bay watershed, outlined in blue. Modified from USGS poster.The Chesapeake Bay Watershed.
Images
Chesapeake Bay watershed, outlined in blue. Modified from USGS poster.The Chesapeake Bay Watershed.
![Spigot sticking out of a pipe in a drinking-water treatment plant](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/drinking_water_plant_spigot_20130409092032_l.jpg?itok=awycpmdK)
Spigot sticking out of a pipe in a drinking-water treatment plant
Spigot sticking out of a pipe in a drinking-water treatment plant
Wellhead inside of a drinking-water plant
Wellhead inside of a drinking-water plant
![USGS scientist collecting a water sample from Boulder Creek, Colorado.](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/BC_Sampling03.jpg?itok=twkS_s5W)
A USGS scientist collecting a water-quality sample from Boulder Creek, Colorado.
A USGS scientist collecting a water-quality sample from Boulder Creek, Colorado.
![Two images, 1) a man holding a mason jar of water, 2) a man pours water onto a sample bottle held by another person.](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/media/images/SurfaceWaters-MicrobiaBiogeochem-merged.png?itok=tqydaV0x)
Left: USGS Employee L. Windham-Myers showing a surface water sample collected in acid-cleaned mason jar (deployed for 24 hours) for a mercury study conducted at the Cosumnes River Nature Preserve (CA). Photographer: M. Marvin-DiPasquale. Date: 10/29/2014.
Left: USGS Employee L. Windham-Myers showing a surface water sample collected in acid-cleaned mason jar (deployed for 24 hours) for a mercury study conducted at the Cosumnes River Nature Preserve (CA). Photographer: M. Marvin-DiPasquale. Date: 10/29/2014.
An Appalachian Mountain Stream in the Spring. Photographed by Samuel H Austin
An Appalachian Mountain Stream in the Spring. Photographed by Samuel H Austin
Flower in Big Meadows, Virginia.
Flower in Big Meadows, Virginia.
![USGS analyst performs DNA extractions in a laboratory](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/dna_extraction_in_usgs_michigan_bacteriological_research_laboratory.jpg?itok=jneq92vI)
A U.S. Geological Survey analyst performs DNA extractions on enriched cultures of water from the study area. Once the DNA was extracted it was used to detect pathogen gene markers using polymerase chain reaction (PCR).
A U.S. Geological Survey analyst performs DNA extractions on enriched cultures of water from the study area. Once the DNA was extracted it was used to detect pathogen gene markers using polymerase chain reaction (PCR).
![USGS Scientist collecting a water-quality sample from the South Fork Zumbro River, MN](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/05373005_zumbro_r_sampling3_20121205_l.jpg?itok=l0mfHgPo)
USGS Scientist collecting a water-quality sample from the South Fork Zumbro River, MN
USGS Scientist collecting a water-quality sample from the South Fork Zumbro River, MN
![USGS scientists recording information on water-quality samples](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/food_chain_contaminant_effects_taking_wq_measurements_crop_l.jpg?itok=JSbytbed)
USGS scientists recording information on water-quality samples and field water-quality parameters
USGS scientists recording information on water-quality samples and field water-quality parameters
Bacteria contained in filter chambers placed in downgradient observation wells were exposed to sulfamethoxazole for 30 days as it traveled past the wells
Bacteria contained in filter chambers placed in downgradient observation wells were exposed to sulfamethoxazole for 30 days as it traveled past the wells
Microbial-Contaminant Interactions Laboratory — Boulder, Colorado. Bacteria contained in filter chambers placed in downgradient observation wells were exposed to sulfamethoxazole for 30 days as it traveled past the wells.
Microbial-Contaminant Interactions Laboratory — Boulder, Colorado. Bacteria contained in filter chambers placed in downgradient observation wells were exposed to sulfamethoxazole for 30 days as it traveled past the wells.
![USGS scientist pauses during field work in a stream impacted by acidic runoff and metal contamination](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/iron_precipitates_in_stream_leipzig_scott_dsc_0080_l.jpg?itok=2YQrhXMV)
USGS scientist pauses during field work in a stream impacted by acidic runoff and metal contamination. Iron precipitates are visible on the stream's rocks. The mesh pyramid is an insect emergence trap.
USGS scientist pauses during field work in a stream impacted by acidic runoff and metal contamination. Iron precipitates are visible on the stream's rocks. The mesh pyramid is an insect emergence trap.
USGS Scientists study the effects of trace metal contamination on diets of stream fish. Vegetation surrounding this relatively pristine stream is dominated by deciduous willow, which are inhabited by riparian spiders that consume adult aquatic insects emerging from the stream. Regionally, streams are impacted by acid mine drainage and natural mineralization.
USGS Scientists study the effects of trace metal contamination on diets of stream fish. Vegetation surrounding this relatively pristine stream is dominated by deciduous willow, which are inhabited by riparian spiders that consume adult aquatic insects emerging from the stream. Regionally, streams are impacted by acid mine drainage and natural mineralization.
![Game camera image of an osprey taken on Poplar Island, Maryland](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/game_camera_osprey_poplar_island_md_lazarus_usgs.jpg?itok=Wnq00WNf)
Game camera image of an osprey taken on Poplar Island, Maryland. Game cameras were used to identify species of fish fed to osprey nestlings. The image was taken during a U.S.
Game camera image of an osprey taken on Poplar Island, Maryland. Game cameras were used to identify species of fish fed to osprey nestlings. The image was taken during a U.S.
![USGS scientist standing in a stream. The rocks in the stream have iron precipitates](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/iron_precipitates_in_stream_leipzig_scott_dsc_0080.jpg?itok=vSmzPpY9)
U.S. Geological Survey (USGS) scientist pauses during field work in a stream impacted by acidic runoff and metal contamination. Iron precipitates are visible on the stream's rocks. The mesh pyramid is an insect emergence trap. A riparian zone rich in terrestrial insects can provide an alternate food source for fish in metal-impacted watersheds.
U.S. Geological Survey (USGS) scientist pauses during field work in a stream impacted by acidic runoff and metal contamination. Iron precipitates are visible on the stream's rocks. The mesh pyramid is an insect emergence trap. A riparian zone rich in terrestrial insects can provide an alternate food source for fish in metal-impacted watersheds.
![The USGS Environmental Health Science Strategy addresses the relationship among environmental drivers](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/EDriver_Env_Org_Diagram_l.png?itok=8_VkCseR)
The USGS Environmental Health Science Strategy addresses the relationship among environmental drivers, exposure to disease agents (contaminants and pathogens), and the complex responses to contaminant and pathogen exposure that result in environmental disease in wildlife, domesticated animals, and people.
The USGS Environmental Health Science Strategy addresses the relationship among environmental drivers, exposure to disease agents (contaminants and pathogens), and the complex responses to contaminant and pathogen exposure that result in environmental disease in wildlife, domesticated animals, and people.
![A scientist collects a groundwater sample with a syringe](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/sampling_with_syringe_bemidji_imag0413_l.jpg?itok=40QQ6nsz)
A scientist collects a groundwater sample to analyze for arsenic and other chemicals from a well installed in a wetland at the National Crude Oil Spill Fate and Natural Attenuation Research Site, near Bemidji, Minnesota.
A scientist collects a groundwater sample to analyze for arsenic and other chemicals from a well installed in a wetland at the National Crude Oil Spill Fate and Natural Attenuation Research Site, near Bemidji, Minnesota.
![U.S. Geological Survey (USGS) scientists prepare a tracer solution to conduct a natural gradient tracer test](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/anammox_tracer_test_prep_dscn2332_l.jpg?itok=qE085XyY)
U.S. Geological Survey (USGS) scientists prepare a tracer solution to conduct a natural gradient tracer test to measure anammox activity in groundwater. The tracer solution is prepared by pumping groundwater into a gas impermeable bladder to maintain the in situ dissolved oxygen concentration and then mixing in the tracer chemicals.
U.S. Geological Survey (USGS) scientists prepare a tracer solution to conduct a natural gradient tracer test to measure anammox activity in groundwater. The tracer solution is prepared by pumping groundwater into a gas impermeable bladder to maintain the in situ dissolved oxygen concentration and then mixing in the tracer chemicals.
![Screen shot of a computer monitor from a video recording setup from an experimental swimming behavior assay system](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/ctt_puglis_swimming_activity_monitoring_img_1012_crop_1024.jpg?itok=20r-cyG8)
Behavioral Toxicology Laboratory — Columbia, Missouri. Screen shot of a computer monitor from a video recording setup from a swimming behavior experimental swimming behavior assay system. U.S. Geological Survey (USGS) scientists can record swimming activity of multiple treatments simultaneously in the swimming behavior assay.
Behavioral Toxicology Laboratory — Columbia, Missouri. Screen shot of a computer monitor from a video recording setup from a swimming behavior experimental swimming behavior assay system. U.S. Geological Survey (USGS) scientists can record swimming activity of multiple treatments simultaneously in the swimming behavior assay.
![Dead eastern pipestrelle (Pipistrellus subflavus) bat shows points of orange-yellow fluorescence when exposed to UV light](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/masonry/public/thumbnails/image/23856_2tricolor_flbwbnwhc_l.jpg?itok=QXjh6wEq)
Wing from dead eastern pipestrelle (Pipistrellus subflavus) bat shows points of orange-yellow fluorescence when exposed to UVlight. From Turner and others, 2014, Figure 1E, page 569.
Wing from dead eastern pipestrelle (Pipistrellus subflavus) bat shows points of orange-yellow fluorescence when exposed to UVlight. From Turner and others, 2014, Figure 1E, page 569.