Wendy R. Eisner

Spatial Extent, Age, and Carbon Stocks in Drained Thaw Lake Basins on the Barrow Peninsula, Alaska

Abstract Thaw lakes and drained thaw lake basins are ubiquitous on the Arctic Coastal Plain of Alaska. Basins are wet depositional environments, ideally suited for the accumulation and preservation of organic material. Much of this soil organic carbon (SOC) is currently sequestered in the near-surface permafrost but, under a warming scenario, could become mobilized. The relative age of 77 basins on the Barrow Peninsula was estimated using the degree of plant community succession and verified by radiocarbon-dating material collected from the base of the organic layer in 21 basins. Using Landsat-7+ imagery of the region, a neural network classifying algorithm was developed from basin age-dependent spectra and texture. About 22% of the region is covered by 592 lakes (>1 ha), and at least 50% of the land surface is covered by 558 drained lake basins. Analysis of cores collected from basins indicates that (1) organic layer thickness and the degree of organic matter decomposition generally increases with basin age, and (2) SOC in the surface organic layer tends to increase with basin age, but the relation for the upper 100 cm of soil becomes obscured due to cryoturbation, organic matter decomposition, and processes leading to ice enrichment in the upper permafrost.

Records of aquatic pollen and sediment properties as indicators of late-Quaternary Alaskan lake levels*

We investigated whether techniques developed to evaluate qualitative lake-level changes in the temperate zone can be used in sub-arctic and arctic Alaska. We focused on aquatic pollen records and sediment properties (loss-on-ignition and magnetic susceptibility) from centrally-located sediment-surface samples and cores, as these are the most commonly reported data in the literature. Modern aquatic pollen values are generally low (< 5%) and may be zero, even in lakes with abundant aquatic macrophytes. Greater diversity and higher values of aquatic pollen are likely at depths < 5 m, but pollen is found in depths up to 15 m. It is absent at depths > 20 m. Spores of Isoetes and Equisetum and Pediastrum cell-nets, when present, tend to be widely distributed, even in deep water. At Birch Lake, interior Alaska, trends in aquatic taxa and sediment characteristics for the last ca. 12,000 14C yrs recorded in a single, deep-water core reflect the same water-level changes as do transect-based lake-level reconstructions - if modern distributional characteristics of pollen and spores are taken into account. The lake rose from extremely low levels at ca. 12,000 14C yr B.P. After a period of fluctuation, it rose to a relatively high level by ca. 8000 14C yr B.P. and then stabilized. A preliminary survey of aquatic pollen trends from other lake-sediment records suggests that the period ca. 11,000-8000 14C yr B.P. may have seen relatively low lake levels in north-western and interior Alaska and high levels thereafter. Changes in aquatic pollen and sediments are evident in north-eastern interior lakes at the same time, but they are more difficult to interpret. Aquatic pollen productivity in Alaskan lakes may partly depend on factors other than water depth (e.g. temperature, pH, nutrient status, or length of the ice-free season). An Alaska-wide reconstruction of late-Quaternary lake levels based on extant single-core data would be best done after further study of contributing factors that may control sediment properties and aquatic pollen distribution.

A long pollen record from Ahaliorak Lake, Arctic Alaska

Abstract The pollen analysis of the top three meters of sediments in Ahaliorak Lake from north of the Brooks Range in arctic Alaska spans from the present to before 30,000 years ago, revealing the history of climate since early in the Boutellier interstade. Comparison with other data show that the record represents the history of regional climate. Climate of the Boutellier interstade was perhaps as warm as some Holocene climates but was significantly drier. Moisture early in the last glaciation suggests partial flooding of the Bering-Chukchi platform. Climate of the glacial maximum was cold and dry until the waning phase of the glaciation when increasing moisture is apparent. The time of the late glacial birch rise was a period of exceptional warmth at Ahaliorak Lake, which then supported a community of Myriophyllum . The vegetation of the Bering land bridge north of the Brooks Range was not a polar desert but neither was it steppe, rather it was poorly productive, dry tundra.

High-resolution pollen analysis of tundra polygons from the North Slope of Alaska

Modern and fossil pollen analyses have established the local vegetation succession and landscape evolution along the Meade River near Atqasuk, Alaska. Three data sets were analyzed: (1) a 142-cm-long peat deposit on the exposed river bluff face, (2) a short, 13-cm peat monolith from the near-surface sediment, and (3) a modern data set of surface samples collected along a transect representative of a geomorphic gradient of low-center, transitional, and high-center polygons. Pollen-microfossil assemblages changed significantly along this gradient. Detailed analysis of the short pollen profile shows successional vegetation changes over the last 250 years. The long profile, a 9400-year record of past vegetation, indicates that initially, the site was covered by shallow lakes. Eolian activity had a substantial effect on sediment deposition, but a period of rapid peat growth from 8500 to 5000 14C year B.P. is coincident with increased vegetation cover of mixed grass-shrub tundra. Following this period, peat growth slowed, and shrub vegetation was replaced by tussock-forming sedge vegetation.

Producing an Indigenous Knowledge Web GIS for Arctic Alaska Communities: Challenges, Successes, and Lessons Learned

A traditional knowledge “Inupiaq Web GIS”, based on a five-year study and containing observations and environmental knowledge of Inupiat communities indigenous to Arctic Alaska, was incorporated into a Web-based platform. The website, “Arctic Cultural Cartography,” was created to be an open portal through which the password-protected “Inupiaq Web GIS” could be accessed. We discuss the process of developing the web GIS including the incorporation of user-friendly features such as links to interactive maps, video clips of interviews, discussion boards, and the integration of popular web interfaces such as Facebook. We also discuss short- and long-term goals for the further development of the GIS, its potential as a sustainable, participatory online database for sharing pertinent ecological knowledge, and challenges in achieving optimal community involvement given constraints imposed by remote locations with limited bandwidth.

Nutarniq: Uniting the Arctic Community with a Wireless Arctic Network for Circumpolar Communications

This paper provides a summary of the current state of telecommunications for eight Arctic nations and a common vision for a Wireless Arctic Network to unite the Arctic Circumpolar Community. It presents detailed requirements based on the North

Environmental, cultural, and social change in Arctic Alaska as observed by Iñupiat elders over their lifetimes: a GIS synthesis

Abstract Since 2003 our research team has been interviewing Iñupiat elders and incorporating their indigenous knowledge (IK) about the environment into a specially designed Geographic Information System (GIS). We present a synthesis of the climate and landscape change information shared during the IK GIS project. We also summarize observations, which are not geographically specific and thus not expressible as GIS data points. We present several analyses of our dataset to date. These include a frequency analysis of the topically classified geocoded observations based on elder interviews, a summary of the geographic distribution of those observations, and a discussion of non-georeferenced observations. We identify several themes that IK holders and elders felt were crucial to record and discuss. Many of these observations include environmental, cultural, and historical knowledge, and reflect the perception that their world has substantially changed in the course of their lifetimes.

Sikuliqiruq: ice dynamics of the Meade River – Arctic Alaska, from freezeup to breakup from time-series ground imagery

Abstract Ice formation and breakup on Arctic rivers strongly influence river flow, sedimentation, river ecology, winter travel, and subsistence fishing and hunting by Alaskan Natives. We use time-series ground imagery of the Meade River to examine the process at high temporal and spatial resolution. Freezeup from complete liquid cover to complete ice cover of the Meade River at Atqasuk, Alaska in the fall of 2008 occurred in less than three days between 28 September and 2 October 2008. Breakup in 2009 occurred in less than two hours between 23:47 UTC on 23 May 2009 and 01:27 UTC on 24 May 2009. All times in UTC. Breakup in 2009 and 2010 was of the thermal style in contrast to the mechanical style observed in 1966 and is consistent with a warming Arctic.