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3 recordsLinked to original sources
USGS2017

At the foot of the smoking mountains: The 2014 scientific investigations in the Islands of the Four Mountains

An interdisciplinary research team conducted archaeological, geological, and biological investigations in the Islands of the Four Mountains, Alaska during the summer of 2014 as part of a three-year project to study long-term geological and ecological patterns and processes with respect to human settlement. Researchers investigated three archaeological sites on Chuginadak Island (SAM-0014, SAM-0016 and SAM-0047) and two archaeological sites on Carlisle Island (AMK-0003 and SAM-0034) as well as peat, tephra, and lava deposition on those islands. These investigations resulted in the delineation of archaeological sites, documentation of geological and cultural stratigraphy, excavation of house-pit features, visual characterization and sampling of potential lithic sources, and documentation of Unangan occupation in the Islands of the Four Mountains from roughly 3,800 years ago to Russian contact.

Arctic Anthropology↗
USGS1998

Holocene geologic and climatic history around the Gulf of Alaska

Though not as dramatic as during the last Ice Age, pronounced climatic changes occurred in the northeastern Pacific over the last 10,000 years. Summers warmer and drier than today's accompanied a Hypsithermal interval between 9 and 6 ka. Subsequent Neoglaciation was marked by glacier expansion after 5-6 ka and the assembly of modern-type plant communities by 3-4 ka. The Neoglacial interval contained alternating cold and warm intervals, each lasting several hundred years to one millennium, and including both the Medieval Warm Period (ca. AD 900-1350) and the Little Ice Age (ca. AD 1350-1900). Salmon abundance fluctuated during the Little Ice Age in response to local glaciation and probably also to changes in the intensity of the Aleutian Low. Although poorly understood at present, climate fluctuations at all time scales were intimately connected with oceanographic changes in the North Pacific Ocean. The Gulf of Alaska region is tectonically highly active, resulting in a history of frequent geological catastrophes during the Holocene. Twelve to 14 major volcanic eruptions occurred since 12 ka. At intervals of 20-100 years, large earthquakes have raised and lowered sea level instantaneously by meters and generated destructive tsunamis. Sea level has often varied markedly between sites only 50-100 km apart due to tectonism and the isostatic effects of glacier fluctuations.

Arctic Anthropology↗
USGS2017

Using gene transcription to assess ecological and anthropological stressors in brown bears

Increasingly, population- and ecosystem-level health assessments are performed using sophisticated molecular tools. Advances in molecular technology enable the identification of synergistic effects of multiple stressors on the individual physiology of different species. Brown bears ( Ursus arctos ) are an apex predator; thus, they are ideal candidates for detecting potentially ecosystem-level systemic perturbations using molecular-based tools. We used gene transcription to analyze 130 brown bear samples from three National Parks and Preserves in Alaska. Although the populations we studied are apparently stable in abundance and exist within protected and intact environments, differences in transcript profiles were noted. The most prevalent differences were among locations. The transcript patterns among groups reflect the influence of environmental factors, such as nutritional status, disease, and xenobiotic exposure. However, these profiles also likely represent baselines for each unique environment by which future measures can be made to identify early indication of population-level changes due to, for example, increasing Arctic temperatures. Some of those environmental changes are predicted to be potentially positive for brown bears, but other effects such as the manifestation of disease or indirect effects of oceanic acidification may produce negative impacts.

Alaska↗