Images

Dwarf least cisco (Coregonus sardinella) were the primary diet item found in stomachs of lake trout (Salvelinus namaycush) from Nutuvukti Lake. These fish, measured at about 90 mm (3.5 in) in length, were reproductively mature. 

Biologists jig for lake trout (Salvelinus namaycush) on Nutuvukti Lake, Gates of the Arctic National Park and Preserve. Thick smoke from wildfires in the Kobuk River and Koyukuk River valleys settled over the lake for a week during field sampling in August.

Emergent vegetation growing in the shallow water of Nutuvukti Lake, Gates of the Arctic National Park and Preserve. Emergent vegetation provides habitat for aquatic insects and small fishes.

USGS researcher collecting one more sample while waiting for the helicopter in Kanuti, Alaska. The Kanuti ophiolite is a mafic-ultramafic thrust sheet of probable Jurassic age, formerly considered to be the upper part of the Yukon-Koyukuk ophiolite (Angayucham terrane).

Mike Knapp, hydraulic engineer with the Alaska Department of Transportation and Public Facilities (far right) introduces USGS hydrologist Taylor Dudunake (back to camera) for a demonstration of multibeam echosounder technology on the Knik River near Palmer, Alaska, July 27, 2023.

The timelapse imagery provided here shows the lower half of Wolverine Glacier from 2012 to 2022. This imagery gives an intuitive view of the scale of change happening at glaciers across Alaska.

RV Norseman II ship track for the Pacific walrus research cruise in 2023. In collaboration with the U.S. Fish and Wildlife Service, USGS conducted a research cruise to study Pacific walrus population dynamics. The ship departed Nome, AK on June 5, 2023, and returned to Nome on July 2, 2023. 

A view of the old Lost River tin mine located on the Seward Peninsula, Alaska. The mine produced tin and tungsten from the early 20th century and ceased around 1955. The site is currently being studied by USGS for lithium potential. 

Scientist sieving a sample of tin placer tailings in Cassiterite Creek on the western Seward Peninsula.

Antimicrobial resistance of clinical relevance may have important implications to human and animal health. In this photo, Laura Scott and Christina Ahlstrom (USGS – Alaska Science Center) are sampling surface waters for antimicrobial resistant bacteria at Exit Creek in Kenai Fjords National Park in Alaska.

Antimicrobial resistance of clinical relevance may have important implications to human and animal health. In this photo, Laura Scott and Christina Ahlstrom (USGS – Alaska Science Center) are sampling surface waters for antimicrobial resistant bacteria at Exit Creek in Kenai Fjords National Park in Alaska.

Antimicrobial resistance of clinical relevance may have important implications to human and animal health. In this photo, Laura Scott and Christina Ahlstrom (USGS – Alaska Science Center) are sampling surface waters for antimicrobial resistant bacteria at Exit Creek in Kenai Fjords National Park in Alaska.

Orange streams are increasingly common in the Brooks Range of northern Alaska. The orange stream color reflects oxidized iron, but also often indicates elevated heavy metal concentrations. Our ongoing study aims to document these occurrences and the timing of their onset.

Kougarok River at the confluence with Taylor Creek, Alaska. Large volume of gold placer tailings that contain critical minerals on the Kougarok River on the western Seward Peninsula.

Orange streams are increasingly common in the Brooks Range of northern Alaska. The orange stream color reflects oxidized iron, but also often indicates elevated heavy metal concentrations. Our ongoing study aims to document these occurrences and the timing of their onset.

A field biologist landed this large 7 kg (15 lb) lake trout (Salvelinus namaycush) on the shore of Chandler Lake, Gates of the Arctic National Park. The lake trout was collected as part of a study investigating the biomagnification of mercury through lake food webs.

Algae collected from rocks in the littoral zone of Chandler Lake, Gates of the Arctic National Park. Algae samples are used to establish an energy baseline for the food web, as primary producers – organisms that produce their own food through photosynthesis – algae provide food to the lake’s benthic macroinvertebrates.

Historic dredge and large volume of gold placer tailings that contain platinum group and chromium critical minerals on the Salmon River near Goodnews Bay, Alaska. Dragline-sluice tailings are in the foreground, stacked dredge tailings are in the background near the dredge.

Large volume of gold placer tailings that contain platinum group and chromium critical minerals on the Salmon River south of Goodnews Bay, Alaska.

The sampling team at Chandler Lake, Gates of the Arctic National Park, walk along the shoreline to a new angling location. While treated to beautiful views, field biologists fished for lake trout (Salvelinus namaycush) as part of a study investigating the biomagnification of mercury through lake food webs. 

The dominant plant in the photo is Arctic sweet coltsfoot (Petasides frigidus), a forage species commonly consumed by barren-ground caribou during the summer in the USFWS Arctic National Wildlife Refuge.