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Full-Text Articles in Physical Sciences and Mathematics

Attribution Of Spatial And Temporal Variations In Terrestrial Methane Flux Over North America, X. F. Xu, Hanqin Tian, C. Zhang, M. L. Liu, Wei Ren, G. S. Chen, Chaoqun (Crystal) Lu, L. Bruhwiler Nov 2010

Attribution Of Spatial And Temporal Variations In Terrestrial Methane Flux Over North America, X. F. Xu, Hanqin Tian, C. Zhang, M. L. Liu, Wei Ren, G. S. Chen, Chaoqun (Crystal) Lu, L. Bruhwiler

Chaoqun (Crystal) Lu

The attribution of spatial and temporal variations in terrestrial methane (CH4) flux is essential for assessing and mitigating CH4 emission from terrestrial ecosystems. In this study, we used a process-based model, the Dynamic Land Ecosystem Model (DLEM), in conjunction with spatial data of six major environmental factors to attribute the spatial and temporal variations in the terrestrial methane (CH4) flux over North America from 1979 to 2008 to six individual driving factors and their interaction. Over the past three decades, our simulations indicate that global change factors accumulatively contributed 23.51 ± 9.61 T g CH4-C (1 Tg = 1012 g) …


Genetic Analysis Of The Federally Endangered Winged Mapleleaf Mussel To Aid Proposed Re-Introduction Efforts, Kevin J. Roe Sep 2010

Genetic Analysis Of The Federally Endangered Winged Mapleleaf Mussel To Aid Proposed Re-Introduction Efforts, Kevin J. Roe

Kevin J. Roe

The winged mapleleaf, Quadrula fragosa, historically occurred in the Mississippi, Tennessee, Ohio, and Cumberland river drainages, but has suffered severe population and range reductions. At the time that the species was federally listed as endangered, its range was thought to have been reduced to a stretch of the St. Croix River between northwestern Wisconsin and east-central Minnesota. Recently, morphologically “Q. fragosa-like” specimens were discovered at sites in Arkansas (Ouachita River and Saline River), Missouri (Bourbeuse River), and Oklahoma (Little River). Subsequently, a plan was proposed to re-introduce Q. fragosa into portions of its historic range where its been extirpated from …


Spatial And Temporal Patterns Of Ch4 And N2o Fluxes In Terrestrial Ecosystems Of North America During 1979–2008: Application Of A Global Biogeochemistry Model, Hanqin Tian, X. Xu, M. Liu, Wei Ren, C. Zhang, G. Chen, Chaoqun (Crystal) Lu Sep 2010

Spatial And Temporal Patterns Of Ch4 And N2o Fluxes In Terrestrial Ecosystems Of North America During 1979–2008: Application Of A Global Biogeochemistry Model, Hanqin Tian, X. Xu, M. Liu, Wei Ren, C. Zhang, G. Chen, Chaoqun (Crystal) Lu

Chaoqun (Crystal) Lu

Continental-scale estimations of terrestrial methane (CH4) and nitrous oxide (N2O) fluxes over a long time period are crucial to accurately assess the global balance of greenhouse gases and enhance our understanding and prediction of global climate change and terrestrial ecosystem feedbacks. Using a process-based global biogeochemical model, the Dynamic Land Ecosystem Model (DLEM), we quantified simultaneously CH4 and N2O fluxes in North America's terrestrial ecosystems from 1979 to 2008. During the past 30 years, approximately 14.69 ± 1.64 T g C a−1 (1 T g = 1012 g) of CH4, and 1.94 ± 0.1 T g N a−1 of N2O …


Physical And Chemical Characterization Of Fuel Ethanol Coproducts Relevant To Value-Added Uses, Rumela Bhadra, Kurt A. Rosentrater, Kasiviswanathan Muthukumarappan Sep 2010

Physical And Chemical Characterization Of Fuel Ethanol Coproducts Relevant To Value-Added Uses, Rumela Bhadra, Kurt A. Rosentrater, Kasiviswanathan Muthukumarappan

Kurt A. Rosentrater

One of the fastest growing industries in the United States is the fuel ethanol industry. In terms of ethanol production capability, the industry has grown by more than 600% since the year 2000. The major coproducts from corn-based ethanol include distillers dried grains with solubles (DDGS) and carbon dioxide. DDGS is used as a livestock feed because it contains high quantities of protein, fiber, amino acids, and other nutrients. The goal of this study was to quantify various chemical and physical properties of DDGS, distillers wet grains (DWG), and distillers dried grain (DDG) from several plants in South Dakota. Chemical …


全球变化与陆地系统综合集成模拟 ——新一代陆地生态系统动态模型 (Dlem), 汉勤 田, 明亮 刘, 弛 张, 巍 任, 小锋 徐, 广生 陈, 超群 吕, 波 陶 Aug 2010

全球变化与陆地系统综合集成模拟 ——新一代陆地生态系统动态模型 (Dlem), 汉勤 田, 明亮 刘, 弛 张, 巍 任, 小锋 徐, 广生 陈, 超群 吕, 波 陶

Chaoqun (Crystal) Lu

人类社会从陆地生态系统获取生产和生活资料的同时也作为一种干扰形式改变着地气之间的动态平衡。这三个既独立又相互耦合的子系统共同组成了一个复杂的陆地系统。如何深入理解这一系统的过程和机制是人类应对气候变化挑战的前提条件。陆地生态系统模型作为一种集成工具,已广泛应用于全球变化研究的各个领域,但从输入数据到模型结构和过程等诸多方面仍存在很大的不确定性。近年来,随着大气和地面生态观测网络的不断完善以及遥感等空间技术的不断强大,使陆地生态系统模型进一步发展和突破成为可能。新一代多因子驱动的陆地生态系统动态模型(Dynamic Land Ecosystem Model, DLEM) 正是在这一背景下 应运而生的。本文旨在介绍DLEM的主体框架、输入输出变量、关键过程、主要功能和特点。


Model Estimates Of Net Primary Productivity, Evapotranspiration, And Water Use Efficiency In The Terrestrial Ecosystems Of The Southern United States During 1895–2007, Hanqin Tian, Guangsheng Chen, Mingliang Liu, Chi Zhang, Ge Sun, Chaoqun (Crystal) Lu, Xiaofeng Xu, Wei Ren, Shufen Pan, Arthur Chappelka Mar 2010

Model Estimates Of Net Primary Productivity, Evapotranspiration, And Water Use Efficiency In The Terrestrial Ecosystems Of The Southern United States During 1895–2007, Hanqin Tian, Guangsheng Chen, Mingliang Liu, Chi Zhang, Ge Sun, Chaoqun (Crystal) Lu, Xiaofeng Xu, Wei Ren, Shufen Pan, Arthur Chappelka

Chaoqun (Crystal) Lu

The effects of global change on ecosystem productivity and water resources in the southern United States (SUS), a traditionally ‘water-rich’ region and the ‘timber basket’ of the country, are not well quantified. We carried out several simulation experiments to quantify ecosystem net primary productivity (NPP), evapotranspiration (ET) and water use efficiency (WUE) (i.e., NPP/ET) in the SUS by employing an integrated process-based ecosystem model (Dynamic Land Ecosystem Model, DLEM). The results indicated that the average ET in the SUS was 710 mm during 1895–2007. As a whole, the annual ET increased and decreased slightly during the first and second half …


Application Of The Tissue Residue Approach In Ecological Risk Assessment, Steven P. Bradbury, Keith G. Sappington, Todd S. Bridges, Russell J. Erickson, A. Jan Hendriks, Roman P. Lanno, James P. Meador, David R. Mount, Mike H. Salazar, Doug J. Spry Jan 2010

Application Of The Tissue Residue Approach In Ecological Risk Assessment, Steven P. Bradbury, Keith G. Sappington, Todd S. Bridges, Russell J. Erickson, A. Jan Hendriks, Roman P. Lanno, James P. Meador, David R. Mount, Mike H. Salazar, Doug J. Spry

Steven P. Bradbury

The objective of this work is to present a critical review of the application of the tissue residue approach (TRA) in ecological risk and/or impact assessment (ERA) of chemical stressors and environmental criteria development. A secondary goal is to develop a framework for integrating the TRA into ecological assessments along with traditional, exposure concentration-based assessment approaches. Although widely recognized for its toxicological appeal, the utility of the TRA in specific applications will depend on numerous factors, such as chemical properties, exposure characteristics, assessment type, availability of tissue residue-response data, and ability to quantify chemical exposure. Therefore, the decision to use …


Meeting The Common Needs Of A More Effective And Efficient Testing And Assessment Paradigm For Chemical Risk Management, Steven P. Bradbury, Vicki Dellarco, Tala Henry, Phil Sayre, Jennifer Seed Jan 2010

Meeting The Common Needs Of A More Effective And Efficient Testing And Assessment Paradigm For Chemical Risk Management, Steven P. Bradbury, Vicki Dellarco, Tala Henry, Phil Sayre, Jennifer Seed

Steven P. Bradbury

Significant advances have been made in human health and ecological risk assessment over the last decade. Substantial challenges, however, remain in providing credible scientific information in a timely and efficient manner to support chemical risk assessment and management decisions. A major challenge confronting risk managers is the need for critical information to address risk uncertainties in large chemical inventories such as high- and medium-production-volume industrial chemicals or pesticide inert ingredients. From a strategic and tactical viewpoint, an integrated approach that relies on all existing knowledge and uses a range of methods, including those from emerging and novel technologies, is needed …


Management Strategies To Improve Yield And Nitrogen Use Of Spring Wheat And Field Pea In The Semi-Arid Northern Great Plains Usa, Andrew W. Lenssen, Brett Allen, Upendra Sainju, Thecan Caesar, Robert Lartey, Robert Evans Jan 2010

Management Strategies To Improve Yield And Nitrogen Use Of Spring Wheat And Field Pea In The Semi-Arid Northern Great Plains Usa, Andrew W. Lenssen, Brett Allen, Upendra Sainju, Thecan Caesar, Robert Lartey, Robert Evans

Andrew W. Lenssen

Available water and N fertility are primary constraints to crop production in the northern Great Plains of the USA. A field trial was initiated in 2004 to compare four crop rotations in a complete factorial of two tillage and two management systems. Rotations were continuous spring wheat (SW), pea-SW, barley hay-pea-SW, and barley hay-corn-pea-SW. Tillage systems were no till and field cultivator tillage, while management systems were conventional and ecological. Conventional management included broadcast nitrogen fertilizer, standard seeding rates, and short stubble height. Ecological management practices varied by crop, and included banded nitrogen fertilizer for cereals, increased seeding rate, delayed …