Physical Sciences and Mathematics Commons^™

A Robust, Multisite Holocene History Of Drift Ice Off Northern Iceland: Implications For North Atlantic Climate, John T. Andrews, Dennis Darby, Dennis Eberle, Anne E. Jennings, Matthias Moros, Astrid Ogilvie

United States Geological Survey: Staff Publications

An important indicator of Holocene climate change is provided by evidence for variations in the extent of drift ice. A proxy for drift ice in Iceland waters is provided by the presence of quartz. Quantitative xray diffraction analysis of the < 2 mm sediment fraction was undertaken on 16 cores from around Iceland. The quartz weight (wt.)% estimates from each core were integrated into 250-yr intervals between −0.05 and 11.7 cal. ka BP. Median quartz wt.% varied between 0.2 and 3.4 and maximum values ranged between 2.8 and 11.8 wt.%. High values were attained in the early Holocene and minimum values were reached 6–7 cal. ka BP. Quartz wt.% then rose steadily during the late Holocene. Our data exhibit no correlation with counts on haematite-stained quartz (HSQ) grains from VM129-191 west of Ireland casting doubt on the ice-transport origin. A pilot study on the provenance of Fe oxide grains in two cores that cover the last 1.3 and 6.1 cal. ka BP indicated a large fraction of the grains between 1 and 6 cal. ka BP were from either Icelandic or presently unsampled sources. However, there was a dramatic increase in Canadian and Russian sources from the Arctic Ocean ~1 cal. ka BP. These data may indicate the beginning of an Arctic Oscillation-like climate mode.

Toxicity Of Polybrominated Diphenyl Ethers (De-71) In Chicken (Gallus Gallus), Mallard (Anas Platyrhynchos), And American Kestrel (Falco Sparverius) Embryos And Hatchlings, Moira A. Mckernan, Barnett A. Rattner, Robert C. Hales, Mary Ann Ottinger

United States Geological Survey: Staff Publications

Embryonic survival, pipping and hatching success, and sublethal biochemical, endocrine, and histological endpoints were examined in hatchling chickens (Gallus gallus), mallards (Anas platyrhynchos), and American kestrels (Falco sparverius) following air cell administration of a pentabrominated diphenyl ether (penta-BDE; DE-71) mixture (0.01–20 µg/g egg) or polychlorinated biphenyl (PCB) congener 126 (3,3’,4,4’,5-pentachlorobiphenyl; 0.002 µg/g egg). The penta-BDE decreased pipping and hatching success at concentrations of 10 and 20 µg/g egg in kestrels but had no effect on survival endpoints in chickens or mallards. Sublethal effects in hatchling chickens included ethoxyresorufin-O-dealkylase (EROD) induction and histological …

Structured Decision Making As A Conceptual Framework To Identify Thresholds For Conservation And Management, Julien Martin, Michael C. Runge, James D. Nichols, Bruce C. Lubow, William L. Kendall

United States Geological Survey: Staff Publications

Thresholds and their relevance to conservation have become a major topic of discussion in the ecological literature. Unfortunately, in many cases the lack of a clear conceptual framework for thinking about thresholds may have led to confusion in attempts to apply the concept of thresholds to conservation decisions. Here, we advocate a framework for thinking about thresholds in terms of a structured decision making process. The purpose of this framework is to promote a logical and transparent process for making informed decisions for conservation.

Specification of such a framework leads naturally to consideration of definitions and roles of different kinds …

Climate Trends Of The North American Prairie Pothole Region 1906–2000, Bruce Millett, W. Carter Johnson, Glenn Guntenspergen

United States Geological Survey: Staff Publications

The Prairie Pothole Region (PPR) is unique to North America. Its millions of wetlands and abundant ecosystem goods and services are highly sensitive to wide variations of temperature and precipitation in time and space characteristic of a strongly continental climate. Precipitation and temperature gradients across the PPR are orthogonal to each other. Precipitation nearly triples from west to east from approximately 300 mm/year to 900 mm/year, while mean annual temperature ranges from approximately 1◦C in the north to nearly 10◦C in the south. Twentieth-century weather records for 18 PPR weather stations representing 6 ecoregions revealed several trends. The climate generally …

Climate Trends Of The North American Prairie Pothole Region 1906–2000, Bruce Millett, W. Carter Johnson, Glenn R. Guntenspergen

United States Geological Survey: Staff Publications

The Prairie Pothole Region (PPR) is unique to North America. Its millions of wetlands and abundant ecosystem goods and services are highly sensitive to wide variations of temperature and precipitation in time and space characteristic of a strongly continental climate. Precipitation and temperature gradients across the PPR are orthogonal to each other. Precipitation nearly triples from west to east from approximately 300 mm/year to 900 mm/year, while mean annual temperature ranges from approximately 1◦C in the north to nearly 10◦C in the south. Twentieth-century weather records for 18 PPR weather stations representing 6 ecoregions revealed several trends. The climate generally …

Structured Decision Making As A Conceptual Framework To Identify Thresholds For Conservation And Management, Julien Martin, Michael C. Runge, James D. Nichols, Bruce C. Lubow, William L. Kendall2

United States Geological Survey: Staff Publications

Threshold and their relevance to conservation have become a major topic of discussion in the ecological literature. Unfortunately, in many cases the lack of a clear conceptual framework for thinking about thresholds in terms of a structured decision making process. The purpose of this framework is to promote a logical and transparent process for making informed decisions for conservation.

Specification of such a framework leads naturally to consideration of definitions and roles of different kinds of thresholds in the process. We distinguish among three categories of thresholds. Ecological thresholds are values of system state variables at which small changes bring …

Possible Sources Of Archaeological Maize Found In Chaco Canyon And Aztec Ruin, New Mexico, Larry Benson, J. R. Stein, H. E. Taylor

United States Geological Survey: Staff Publications

Maize played a major role in Chaco’s interaction with outlying communities in the southern Colorado Plateau. This paper seeks to determine where archaeological corn cobs brought to Chaco Canyon were grown. Strontium-isotope and trace-metal ratios of 180 soil-water and 18 surface-water sites in the Southern Colorado Plateau have revealed possible source areas for some of 37 archaeological corn cobs from Chaco Canyon and 10 archaeological corn cobs from Aztec Ruin, New Mexico. The most probable source areas for cobs that predate the middle-12th-century drought include several Upper Rio Chaco sites (not including Chaco Canyon). There are many potential source areas …

The Neoglacial Landscape And Human History Of Glacier Bay, Glacier Bay National Park And Preserve, Southeast Alaska, Usa, Cathy Connor, Greg Streveler, Austin Post, Daniel Monteith, Wanye Howell

United States Geological Survey: Staff Publications

The Neoglacial landscape of the Huna Tlingit homeland in Glacier Bay is recreated through new interpretations of the lower Bay’s fjordal geomorphology, late Quaternary geology and its ethnographic landscape. Geological interpretation is enhanced by 38 radiocarbon dates compiled from published and unpublished sources, as well as 15 newly dated samples. Neoglacial changes in ice positions, outwash and lake extents are reconstructed for c. 5500–200 cal. yr ago, and portrayed as a set of three landscapes at 1600–1000, 500–300 and 300–200 cal. yr ago. This history reveals episodic ice advance towards the Bay mouth, transforming it from a fjordal seascape into …

History Of Wildlife Toxicology, Barnett A. Rattner

United States Geological Survey: Staff Publications

The field of wildlife toxicology can be traced to

the late nineteenth and early twentieth centuries. Initial

reports included unintentional poisoning of birds from

ingestion of spent lead shot and predator control agents,

alkali poisoning of waterbirds, and die-offs from maritime

oil spills. With the advent of synthetic pesticides in the

1930s and 1940s, effects of DDT and other pesticides were

investigated in free-ranging and captive wildlife. In

response to research findings in the US and UK, and the

publication of Silent Spring in 1962, public debate on the

hazards of pollutants arose and national contaminant

monitoring programs were initiated. …