• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 8
  • 1
  • Tagged with
  • 12
  • 12
  • 12
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Assessment of Heavy Metals in Subsistence-Harvested Alaskan Marine Mammal Body Tissues and Vibrissae

Ferdinando, Pilar M 26 April 2019 (has links)
The coastal, indigenous communities around Alaska have subsisted on marine animals for generations, often focusing on large apex predators such as seals, sea lions, and whales. Three species of pinnipeds (harbor seal, Steller sea lion, northern fur seal) and the northern sea otter have all undergone significant population declines since the 1970s, some regions more than others. Archived vibrissae (whiskers) and body tissues from these four species were available from the Bering Sea and throughout the Gulf of Alaska from the 1990s and early 2000s. Tissues from these species are exceedingly difficult to obtain; thus, the archived tissues provided a finite and irreplaceable resource of data. Analysis of these archived tissues indicates which species, tissues, and gender bioaccumulate metals more readily. In this study twelve heavy metals (arsenic, cadmium, chromium, cobalt, copper, lead, manganese, mercury, nickel, selenium, vanadium, zinc) were analyzed in vibrissae from the four select species, and in body tissues from harbor seals and Steller sea lions. The samples were collected from three regions (southeastern, southcentral, and southwestern Alaska) during the 1990s through early 2000s. Significant differences of heavy metal concentrations in vibrissae were detected among elements (p2(110) = 454.81, p2(66) = 310.88, p
12

Natural science and the American government: fur seal management from gilded age to progressive era

Daitch, Vicki 14 August 2009 (has links)
This thesis examines the study and management of Alaskan fur seals from 1867 to 1914. Government involvement in resource conservation expanded during this period, as did the role of experts. Federal officials charged with managing fur seals often sought advice from scientists, and over the years naturalists studied the animals regularly. Despite this apparent cooperation, scientific recommendations rarely took precedence over other considerations. Fur seal history illuminates obstacles facing scientists as they tried, and failed, to control resource use. Scientists often lost credibility as a result of the changing nature of their profession, but, as this study shows, the most important barriers to expert influence were entrenched economic, political, and diplomatic agendas within the federal government. / Master of Arts

Page generated in 0.0627 seconds