Pre-Settlement Vegetation at Casey\u27s Paha State Preserve, Iowa

Paha are loess-capped ridges standing 10-30 m above the surrounding plain of the Iowan Surface. Although Iowa was almost entirely covered with prairie and wetlands just prior to Euro-American settlement, the paha are believed to have been forested based on soil types and on early vegetation maps. The objective of this study was to find evidence that paha were forested by measuring the δ13C value of humin, the fraction of soil organic matter that is insoluble in acid and base. Previous work has shown that humin retains the δ13C signature of vegetation on a 1000-year time scale, as opposed to the more mobile and soluble humic and fulvic acids that reflect the δ13C signature of more recent vegetation. Soil samples were obtained from Casey\u27s Paha State Preserve in Tama County from four locations at depths ranging from 5-85 cm. Carbonates were removed with 1.0 M HCl and humic and fulvic acids were removed by repeated application of 0.5 M NaOH. The δ13C values of the humin fraction (-22.031% to -24.358%) were within or slightly above the upper range of δ13C values for woody vegetation (-23% to -34%) and well below the range for prairie grasses (-9% to -17%). Although it has been suggested that prairie fires bypassed the paha or that perched water tables maintained the forest, we suggest that the paha forests resulted from activity by Native Americans

A method to measure lactate recycling in cultured cells by edited 1H nuclear magnetic resonance spectroscopy

http://www.sciencedirect.com/science/article/B6W9V-4PF6B5M-1/1/385b6c0836057ee00a92ea234317f1e

Laboratory Abrasion of Crinoid Columnals and the Provenance of the Chariton Conglomerate, South-Central Iowa

The Chariton Conglomerate is a quartz limestone conglomerate of Pennsylvanian age found in six exposures in southern Iowa and three exposures in northern Missouri. Distinctive features of the exposures in Iowa include quartz granules and rounded crinoid columnals. The objective of this study was to determine whether the quartz clasts could have originated in the crystalline rocks of Minnesota or Wisconsin. The average paleocurrent direction measured in interbedded sandstones was 178° (S.D. = 35 °). The average roundness of 75 crinoid columnals extracted from four exposures in Iowa was 30% (S.D. = 14%), defined as roundness(%) = (D-d)/D x 100, where D is the maximum columnal diameter and d is the diameter of the flat circle at the end of the columnal. Previously unabtaded crinoid columnals were abraded in rotary tumblers, which were filled 90% with water and 10% with a mixture representative of the Chariton Conglomerate. The roundness values of the experimentally abraded columnals were consistent with the roundness values of the columnals collected in the field (within one standard deviation of the mean for the field data) for tumbling times in the range 0-33 days. Assuming the travel distance corresponding ro one revolution is the circumference of the barrel, the experimental roundness values were consistent with the field roundness values for travel distances in the range 0-700 km, which is sufficiently far to include the crystalline rocks of Minnesota and Wisconsin

Best practice framework and principles for monitoring the effect of coastal development on marine mammals

As the world's human population increases along the coastal zone, with major alteration of coastal embayments, increased on-water activities and a plethora of other intrusions into the coastal zone, there is a simultaneous increase in pressures on marine mammals. Growing evidence indicates that many marine mammals are highly susceptible to declines resulting from direct and indirect impacts arising from diverse human activities. Too frequently, assessment of the impact from coastal developments on marine mammals has been inadequate or completely lacking. At worst this has led to catastrophic decline in some populations. Without rigorous ecological assessments along with adaptive management frameworks prior to the initiation of developments, the number of marine mammal populations likely to be adversely impacted will continue to rise. To address these shortcomings, we present a globally applicable best practice framework by; (i) describing guiding principles and; (ii) reviewing appropriate procedures for assessment and monitoring of impacts of coastal developments on marine mammals. The approach outlined is embedded in Environmental Impact Assessment processes as a means by which decision makers and stakeholders can be informed. Recommendations presented are designed to encourage the application of robust scientific evaluation that applies appropriate survey design with sufficient statistical power to detect changes before trigger thresholds are reached. We emphasize that there is an urgent need to ensure assessments are comprehensive, effective and integrated with monitoring and adaptive management actions in order to minimize or effectively mitigate the impacts of human activities on marine mammal populations