Loess–paleosol carbonate clumped isotope record of late Pleistocene–Holocene climate change in the Palouse region, Washington State, USA

2018 ◽  
Vol 90 (2) ◽  
pp. 331-347 ◽  
Author(s):  
Alex R. Lechler ◽  
Katharine W. Huntington ◽  
Daniel O. Breecker ◽  
Mark R. Sweeney ◽  
Andrew J. Schauer
Keyword(s):  
Pacific Northwest ◽  
Late Pleistocene ◽  
Climate Model ◽  
The United States ◽  
Soil Conditions ◽  
Isotopic Study ◽  
The Holocene ◽  
Last Glacial ◽  
Carbonate Formation ◽  
Clumped Isotope

AbstractThe Channeled Scabland–Palouse region of the Pacific Northwest (PNW) of the United States preserves geomorphic and pedosedimentary records that inform understanding of late Pleistocene–Holocene paleoclimate change in a region proximal to the last glacial period Cordilleran Ice Sheet. We present a clumped (Δ47) and conventional (δ18O, δ13C) isotopic study of Palouse loess–paleosol carbonates in combination with carbonate radiocarbon (14C) dating to provide new measures of regional late–last glacial (~31–20 cal ka BP) and Holocene soil conditions. Average clumped isotope temperatures (T(Δ47)) for last glacial Palouse loess–paleosol carbonates (9±4°C) are significantly lower than those for Holocene-aged carbonates (T(Δ47)=18±2°C) in study sections. Calculated soil water δ18OVSMOWvalues (−16±2‰) for last glacial carbonates are also offset relative to those for Holocene-aged samples (−11±1‰), whereas calculated soil CO2δ13CVPDBvalues are similar for the Holocene (−16.9±0.2‰) and late–last glacial (−16.7±1.1‰) periods. Together, these paleoclimate metrics indicate late–last glacial conditions of pedogenic carbonate formation in the C3grassland soils of the Palouse were measurably colder (9±5°C) than during the Holocene and potentially reflect a more arid last glacial paleoclimate across the Palouse, findings in agreement with previous proxy studies and climate model simulations for the region.

scholarly journals Clumped isotope constraints on changes in latest Pleistocene hydroclimate in the northwestern Great Basin: Lake Surprise, California

2020 ◽  
Vol 132 (11-12) ◽  
pp. 2669-2683
Author(s):  
L.M. Santi ◽  
A.J. Arnold ◽  
D.E. Ibarra ◽  
C.A. Whicker ◽  
J.A. Mering ◽  
...  
Keyword(s):  
Last Glacial Maximum ◽  
Great Basin ◽  
Climate Model ◽  
Glacial Maximum ◽  
Model Simulations ◽  
Last Glacial ◽  
Climate Forcings ◽  
Clumped Isotope ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Abstract During the Last Glacial Maximum (LGM) and subsequent deglaciation, the Great Basin in the southwestern United States was covered by numerous extensive closed-basin lakes, in stark contrast with the predominately arid climate observed today. This transition from lakes in the Late Pleistocene to modern aridity implies large changes in the regional water balance. Whether these changes were driven by increased precipitation rates due to changes in atmospheric dynamics, decreased evaporation rates resulting from temperature depression and summer insolation changes, or some combination of the two remains uncertain. The factors contributing to these large-scale changes in hydroclimate are critical to resolve, given that this region is poised to undergo future anthropogenic-forced climate changes with large uncertainties in model simulations for the 21st century. Furthermore, there are ambiguous constraints on the magnitude and even the sign of changes in key hydroclimate variables between the Last Glacial Maximum and the present day in both proxy reconstructions and climate model analyses of the region. Here we report thermodynamically derived estimates of changes in temperature, precipitation, and evaporation rates, as well as the isotopic composition of lake water, using clumped isotope data from an ancient lake in the northwestern Great Basin, Lake Surprise (California). Compared to modern climate, mean annual air temperature at Lake Surprise was 4.7 °C lower during the Last Glacial Maximum, with decreased evaporation rates and similar precipitation rates to modern. During the mid-deglacial period, the growth of Lake Surprise implied that the lake hydrologic budget briefly departed from steady state. Our reconstructions indicate that this growth took place rapidly, while the subsequent lake regression took place over several thousand years. Using models for precipitation and evaporation constrained from clumped isotope results, we determine that the disappearance of Lake Surprise coincided with a moderate increase in lake temperature, along with increasing evaporation rates outpacing increasing precipitation rates. Concomitant analysis of proxy data and climate model simulations for the Last Glacial Maximum are used to provide a robust means to understand past climate change, and by extension, predict how current hydroclimates may respond to expected future climate forcings. We suggest that an expansion of this analysis to more basins across a larger spatial scale could provide valuable insight into proposed climate forcings, and aid in climate model process depiction. Ultimately, our analysis highlights the importance of temperature-driven evaporation as a mechanism for lake growth and retreat in this region.

scholarly journals Insight into the Productivity, Cost and Soil Impacts of Cable-assisted Harvester-forwarder Thinning in Western Oregon

2019 ◽  
Vol 66 (1) ◽  
pp. 82-96 ◽  
Author(s):  
Preston Q Green ◽  
Woodam Chung ◽  
Ben Leshchinsky ◽  
Francisca Belart ◽  
John Sessions ◽  
...  
Keyword(s):  
Pacific Northwest ◽  
Soil Compaction ◽  
The United States ◽  
Soil Conditions ◽  
Productivity Cost ◽  
System Productivity ◽  
Machine Productivity ◽  
Before And After ◽  
Harvesting Systems ◽  
Soil Measurements

Abstract Cable-assisted (or tethered) mechanized harvesting has recently been introduced to the Pacific Northwest of the United States, and is rapidly being adopted by the forest industry. However, potential environmental impacts, productivity and cost of the new harvesting systems have not been well-assessed. This study aims to examine the effects of cable assistance on soil compaction, system productivity and cost through a field-based experiment. A harvester-forwarder system was used to thin a harvest unit on dry soils in western Oregon, with and without cable-assistance. We conducted a detailed time study during operations and collected soil measurements before and after machine passes. Machine productivity ranged from 28.75 to 92.36 m3 per scheduled machine hour, with resulting unit costs for untethered and tethered systems ranging from $13.19 to $18.13/m3. Our results showed reduced soil impacts in both extent and degree of soil compaction when cable assistance was employed. The reduced extent of soil impacts is attributed to a reduction in track wander owing to the operative tensions of the tether cable, and the smaller increase in soil density appears to be attributed to combined effects of initially denser soil conditions and reduced shear displacement as a result of cable-assistance.

scholarly journals Exploring the phylogeography and population dynamics of the giant deer ( Megaloceros giganteus ) using Late Quaternary mitogenomes

2021 ◽  
Vol 288 (1950) ◽  
Author(s):  
Alba Rey-Iglesia ◽  
Adrian M. Lister ◽  
Paula F. Campos ◽  
Selina Brace ◽  
Valeria Mattiangeli ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Last Glacial Maximum ◽  
Late Pleistocene ◽  
Late Quaternary ◽  
Glacial Maximum ◽  
Climatic Fluctuations ◽  
The Holocene ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Late Quaternary climatic fluctuations in the Northern Hemisphere had drastic effects on large mammal species, leading to the extinction of a substantial number of them. The giant deer ( Megaloceros giganteus ) was one of the species that became extinct in the Holocene, around 7660 calendar years before present. In the Late Pleistocene, the species ranged from western Europe to central Asia. However, during the Holocene, its range contracted to eastern Europe and western Siberia, where the last populations of the species occurred. Here, we generated 35 Late Pleistocene and Holocene giant deer mitogenomes to explore the genetics of the demise of this iconic species. Bayesian phylogenetic analyses of the mitogenomes suggested five main clades for the species: three pre-Last Glacial Maximum clades that did not appear in the post-Last Glacial Maximum genetic pool, and two clades that showed continuity into the Holocene. Our study also identified a decrease in genetic diversity starting in Marine Isotope Stage 3 and accelerating during the Last Glacial Maximum. This reduction in genetic diversity during the Last Glacial Maximum, coupled with a major contraction of fossil occurrences, suggests that climate was a major driver in the dynamics of the giant deer.

Coastal occupation and foraging during the last glacial maximum and early Holocene at Waterfall Bluff, eastern Pondoland, South Africa

2020 ◽  
Vol 97 ◽  
pp. 1-41 ◽  
Author(s):  
Erich C. Fisher ◽  
Hayley C. Cawthra ◽  
Irene Esteban ◽  
Antonieta Jerardino ◽  
Frank H. Neumann ◽  
...  
Keyword(s):  
South Africa ◽  
Continental Shelf ◽  
Last Glacial Maximum ◽  
Late Pleistocene ◽  
Marine Fish ◽  
Hunter Gatherers ◽  
The Holocene ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
The Last Glacial

AbstractWaterfall Bluff is a rock shelter in eastern Pondoland, South Africa, adjacent to a narrow continental shelf that limited coastline movements across glacial/interglacial cycles. The archaeological deposits are characterized by well-preserved stratigraphy, faunal, and botanical remains alongside abundant stone artifacts and other materials. A comprehensive dating protocol consisting of 5 optically stimulated luminescence ages and 51 accelerator mass spectrometry 14C ages shows that the record of hunter-gatherer occupations at Waterfall Bluff persisted from the late Pleistocene to the Holocene, spanning the last glacial maximum and the transition from the Pleistocene to the Holocene. Here, we provide detailed descriptions about the sedimentary sequence, chronology, and characteristics of the archaeological deposits at Waterfall Bluff. Remains of marine mollusks and marine fish also show, for the first time, that coastal foraging was a component of some hunter-gatherer groups’ subsistence practices during glacial phases in the late Pleistocene. The presence of marine fish and shellfish further demonstrates that hunter-gatherers selectively targeted coastal resources from intertidal and estuarine habitats. Our results therefore underscore the idea that Pondoland's coastline remained a stable and predictable point on the landscape over the last glacial/interglacial transition being well positioned for hunter-gatherers to access resources from the nearby coastline, narrow continental shelf, and inland areas.

Nutrient-Use Patterns in Nursery Crops

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 557a-557
Author(s):  
Mary Ann Rose ◽  
Barbara Biernacka
Keyword(s):  
Nutrient Retention ◽  
The United States ◽  
Soil Conditions ◽  
Woody Ornamentals ◽  
Use Patterns ◽  
Nutrient Demand ◽  
Nutrient Use ◽  
Fertilizer Recommendations ◽  
Retention Characteristics ◽  
Practical Constraints

Long-standing fertilizer recommendations for field-grown nursery and landscape ornamentals are based on maximizing growth, not nutrient efficiency. Further, these recommendations fall short because of failure to consider 1) the extent of crop nutrient removal, 2) varying nutrient retention characteristics of soils across the United States, and 3) a body of research that suggests that woody ornamentals have a limited response to fertilization under most soil conditions. Concern for the environmental impact of fertilization justifies a reevaluation of current nursery fertilization practices, as well a discussion of the practical constraints on the adoption of new approaches, e.g., nutrient demand-driven fertilization. Research on the nutrient use patterns of woody plants will be reviewed with emphasis on implications for increasing fertilization efficiency. OSU research on water availability and nutrient-use interactions also will be presented.

scholarly journals First record of Euxestonotus error (Hymenoptera: Platygastridae) in the Pacific Northwest, United States of America

2016 ◽  
Vol 148 (5) ◽  
pp. 616-618 ◽  
Author(s):  
E.R. Echegaray ◽  
R.N. Stougaard ◽  
B. Bohannon
Keyword(s):  
United States ◽  
New York ◽  
Pacific Northwest ◽  
United States Of America ◽  
First Record ◽  
The United States ◽  
Sitodiplosis Mosellana ◽  
Wheat Midge ◽  
The Pacific ◽  
Northwestern Montana

AbstractEuxestonotus error (Fitch) (Hymenoptera: Platygastridae) is considered part of the natural enemy complex of the wheat midge Sitodiplosis mosellana (Géhin) (Diptera: Cecidomyiidae). Although previously reported in the United States of America, there is no record for this species outside the state of New York since 1865. A survey conducted in the summer of 2015 revealed that E. error is present in northwestern Montana and is likely playing a role in the suppression of wheat midge populations.

Does School Climate Mean the Same Thing in the United States as in Mexico? A Focus on Measurement Invariance

2017 ◽  
Vol 37 (1) ◽  
pp. 55-68 ◽  
Author(s):  
Kathan D. Shukla ◽  
Tracy E. Waasdorp ◽  
Sarah Lindstrom Johnson ◽  
Mercedes Gabriela Orozco Solis ◽  
Amanda J. Nguyen ◽  
...  
Keyword(s):  
United States ◽  
School Climate ◽  
Measurement Invariance ◽  
School Environment ◽  
Climate Model ◽  
The United States ◽  
School Students ◽  
Scale Scores ◽  
Partial Invariance ◽  
The U.S

School climate is an important construct for guiding violence prevention efforts in U.S. schools, but there has been less consideration of this concept in its neighboring country Mexico, which has a higher prevalence of violence. The U.S. Department of Education outlined a three-domain conceptualization of school climate (i.e., safe and supportive schools model) that includes engagement, safety, and the school environment. To examine the applicability of this school climate model in Mexico, the present study tested its measurement invariance across middle school students in the United States ( n = 15,099) and Mexico ( n = 2,211). Findings supported full invariance for engagement and modified-safety scales indicating that factor loadings and intercepts contributed almost equally to factor means, and scale scores were comparable across groups. Partial invariance was found for the environment scales. Results of a multigroup confirmatory factor analysis (MGCFA) consisting of all 13 school climate scales indicated significantly positive associations among all scales in the U.S. sample and among most scales in the Mexico sample. Implications of these findings are discussed.

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