We thank Anne Gibson, Katherine Jones, Chris Kolodziejczyk, Alicia Naranjo, Kyle Tiner, and numerous students and temporary technicians for operating the LYCOG facility, conducting sampling, and data processing. L.G.R. acknowledges USDA-NIFA (2010-65615-20632).

1. Monólitos Coletar solo a ser usado como lisímetros de pesagem <ol><li> Construir caixas de aço abertas 1 x 1 m quadrados por 1,5 m de profundidade entre 8 mm de espessura de aço. </li><li> Pressione as caixas abertas verticalmente no solo, com prensas hidráulicas montadas em âncoras helicoidais perfurado 3 m de profundidade no solo. </li><li> Escavar o monólito envolto utilizando uma retroescavadeira ou equipamento similar. </li><li> Coloque um pavio em fibra de vidro em contacto com o solo na base do monólito. Passe o pavio por meio da base de aço para um reservatório de 10 L para drenar o monólito, e, em seguida, soldar o aço de base na parte inferior da caixa. </li><li> Matar a vegetação existente nos monolitos pela aplicação de um herbicida não-residuais, tais como o glifosato. </li></ol> 2. Estabelecer Comunidades Vegetais em monólitos de solos <ol><li> Planta os monólitos com oito mudas cada um dos sete espécies de gramíneas e Tallgrass Prairie forbs, para uma densidade total de 56 plantas por m 2. <ol><li&gt; Vegetal os seguintes: Gramas Bouteloua curtipendula (lado aveia grama), Schizachyrium scoparium (pouco bluestem), nutans Sorghastrum (Indiangrass), tridens albescens (tridens branco)]. </li><li> Plante as seguintes Forbs: azurea Salvia (pitcher sábio), Solidago canadensis (Canadá goldenrod), a flor do ilinóis (Illinois Bundleflower, uma leguminosa). </li></ol></li><li> Mudas de plantas em um quadrado latino, re-randomizados para cada monólito. </li><li> Regar os transplantes de aproximadamente 2 meses após o plantio. O objetivo é minimizar o estresse hídrico durante o estabelecimento inicial. Usar qualquer método conveniente, como uma varinha de mão ou aspersão jardim. A freqüência da rega depende do clima e do tempo local, particularmente a ocorrência de precipitação ambiente. </li><li> Após a primeira fase estabelecimento de transplante, manter os transplantes sob chuva ambiente por tanto tempo quanto necessário, enquanto câmaras (Seção3) são construídos. Retirar espécies indesejadas que emergem nos monólitos durante o estabelecimento por mão-de capina. </li></ol> 3. Câmara projeto <ol><li> Construir duas câmaras cada 1,2 m de largura, 1,5 m de altura e 60 m de comprimento, dividido em dez seções 5 m de comprimento. Construir seções de aço pesado de dimensões 5 mx 1,2 mx 1,6 m de profundidade, enterrado a 1,5 m. <ol><li> Instale quatro monólitos em cada seção, dois monolitos cada um de dois dos tipos de solo, em ordem aleatória. Instale cada monólito no topo de um equilíbrio de capacidade 4,540 kg. </li><li> Incluir monólitos Bastsil nos emparelhamentos em seções de números pares. </li></ol></li><li> Junte-se secções adjacentes acima do solo com 1 m de comprimento x 1 m de largura x 0,3 m de altura do duto de chapa para fornecer um caminho para o fluxo de ar. <ol><li> Fornecimento de líquido de arrefecimento a 10 ° C a partir de uma unidade de refrigeração 161,4 kW a uma serpentina de arrefecimento no interior de cada conduta. </li><li> Coloque a vegetação com filme claro com efeito de estufa (espessura 0,006 &quot;/. 15 mm), tal como usado na outraexperimentos de manipulação do clima 23. </li><li> Encaixe cada tampa com uma abertura com zíper apoiada por um projecto de retalho para permitir o acesso aos monolitos para a amostragem. </li><li> Remover o polietileno cobre no final da estação de crescimento. </li></ol></li></ol> 4. CO 2 e temperatura do ar Medição; Controle de temperatura <ol><li> Amostra entrada e saída C A em ambas as câmaras cada 2 minutos através de linhas de amostra de ar filtrado localizados na entrada e saída de câmaras superambientes e subambient. Estes dados informar injeção de CO 2 e ventilador de controle de velocidade. <ol><li> Teor de vapor de água C ​​Amostra A e, e temperatura do ar medida (T A) na entrada e saída de cada seção 5 m em intervalos de 20 min. </li><li> Meça todas as amostras de ar para CO2 e teor de vapor de água em tempo real usando analisadores de gás infravermelho de acordo com o protocolo do fabricante. </li><li> Meça T A na entrada, ponto médio, umd saída de cada seção com termopares de fios finos blindados. </li></ol></li><li> Regular o fluxo de fluido de arrefecimento através da serpentina de refrigeração na entrada de cada secção para manter uma média consistente (mid) T A secção para secção de perto o ambiente T A. </li><li> Posicione um sensor de quantum para ter uma visão desobstruída do céu e medir fótons fotossintéticos densidade de fluxo de acordo com o protocolo do fabricante. Nível de luz é uma entrada para o algoritmo de controle do ventilador. </li></ol> 5. C A aplicação dos tratamentos <ol><li> Dia <ol><li> Misturar puro de dióxido de carbono (CO 2) com ar ambiente com 500 ul de entrada L -1 C A, usando um controlador de fluxo de massa no canal de entrada da perna superambientes. Ver Seção 4 para C A medida mais detalhes. </li><li> Advect o ar enriquecido através das câmaras utilizando ventoinhas à entrada da secção 1 e nas seções a jusante. </li><li> Manter a saída C A 390 ul de L-1 (ar ambiente) desejado, ajustando a velocidade do ventilador. <ol><li> Aumente a velocidade do ventilador, se a saída C A estiver abaixo do ponto de ajuste. Isto permite que menos tempo para absorção pelas plantas de CO 2, resultando em maior saída C A. </li><li> Diminuir a velocidade do ventilador, se a saída C Um está acima do ponto de ajuste. </li></ol></li><li> Use a mesma abordagem na câmara subambient exceto introduzir ar ambiente e controle para alcançar a saída C Um de 250 mL L -1. </li></ol></li><li> Nighttime <ol><li> Inverter o sentido do fluxo de ar. </li><li> Injetar CO 2 na extremidade de saída da câmara de dia superambientes para atingir 530 mL L -1 C A, e as taxas de controle advecção de manter 640 mL L -1 na saída noite (entrada dia. </li><li> Introduzir ar ambiente em ~ 390 mL L -1 de CO 2 para a entrada noturna(saída dia) da velocidade do controlo e advection câmara para manter subambient 530 ul L-1 na saída noite. </li></ol></li></ol> 6. Entradas de precipitação <ol><li> Aplique a quantidade média de chuva estação de crescimento para cada monólito. <ol><li> Abastecimento de água para cada monólito de uma fonte de água para uso doméstico através de um sistema de irrigação por gotejamento. Agendar os eventos de irrigação e as quantidades de aplicação para aproximar o padrão sazonal de chuva para a localização experimento. O horário exato depende do clima local. </li></ol></li><li> Controle de tempo de aplicação com um registrador de dados e medir volumes de aplicativos com medidores de vazão. </li></ol> 7. Amostragem <ol><li> Medir perfis verticais de volumétrico de água no solo (vSWC) semanalmente durante o período de CO 2 de controle, com um medidor de atenuação ou outra sonda de nêutrons apropriado. <ol><li> Incrementos perfil recomendadas são incrementos de profundidade de 20 cm a 1 m dePTH, e um incremento de 50 cm abaixo de 1 m. </li></ol></li><li> Medida monólito biomassa aérea da produtividade primária líquida (ANPP) colhendo tudo biomassa acima do solo de pé no final da estação de crescimento. <ol><li> Todos biomassa acima do solo é removido a cada ano, em consequência de pé biomassa representa a produção primária atual. </li><li> Classificar a biomassa recolhidos por meio de espécies e seco para massa constante, e pesar. </li><li> Use biomassa de espécies individuais para quantificar espécies de plantas contribuições para ANPP. </li></ol></li></ol>

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The authors have nothing to disclose.

A instalação LYCOG atinge seu objetivo operacional de manutenção de um 250 a 500 mL L -1 gradiente contínuo das concentrações de C A em comunidades experimentais de pastagens estabelecidas em três tipos de solo. A mudança de C A é linear dentro do intervalo prescrito. Temperatura do ar aumentou dentro de cada seção, mas foi reposta pelas bobinas entre-seção de arrefecimento na maioria dos setores. Como resultado, o objectivo operacional de manter a temperatura média consis...

Atmosférica concentração de dióxido de carbono (C A) aumentou recentemente passado de 400 mL L -1 de cerca de 270 mL L -1 antes da Revolução Industrial. C A previsão é de atingir pelo menos 550 mL L -1 em 2100 1. Esta taxa de aumento supera quaisquer alterações C Um observadas ao longo dos últimos 500.000 anos. A taxa sem precedentes de mudança na C Um levanta a possibilidade de respostas não-lineares ou limiar de ecossistemas para aumentar Um C. A maioria ecossistema escala C Um experimentos de enriquecimento de aplicar apenas dois tratamentos, um único nível de C enriquecido A e um controle. Estas experiências têm expandido nossa compreensão sobre os impactos nos ecossistemas de C Um enriquecimento. No entanto, uma abordagem alternativa que pode revelar a presença de respostas não lineares dos ecossistemas para aumentar C A é para estudar ecossistemas através de uma gama contínua de a subambientUm superambientes C. Subambient C Um é difícil de manter no campo, e tem sido mais estudados utilizando câmaras de crescimento 2. A superambientes C foi estudada usando câmaras de crescimento, câmaras de topo aberto, e técnicas de enriquecimento livre de ar 3, 4. C Um enriquecimento ocorre através das paisagens que contêm muitos tipos de solo. Propriedades solos pode afetar fortemente as respostas dos ecossistemas para C Um enriquecimento. Por exemplo, a textura do solo determina a retenção de água e nutrientes no perfil do solo 5, a sua disponibilidade para as plantas 6, e da quantidade e qualidade da matéria orgânica 7-9. A disponibilidade de umidade do solo é um mediador crucial das respostas do ecossistema para C Um enriquecimento em sistemas de água, limitadas, incluindo a maioria das pradarias 10. Campo passado C Um experimentos de enriquecimento de ter examinado normalmente apenas um tipo de solo e testes de v continuamente controladatipos arying C Um enriquecimento do solo ao longo de vários faltam. Se os efeitos de C Um enriquecimento nos processos do ecossistema diferem com o tipo de solo, há uma forte razão para esperar variação espacial nas respostas do ecossistema para C Um enriquecimento e consequentes alterações climáticas 11, 12. O Dióxido de Carbono Lysimeter Gradiente (LYCOG) instalação foi projetado para tratar de questões de variação espacial nas respostas não lineares e limiar de ecossistemas para níveis que vão de A C ~ 250 a 500 mL L -1. LYCOG cria o gradiente prescrita de C Um em comunidades perenes pastagem de plantas que crescem em solos que representam a ampla gama de textura, teores de N e C, e propriedades hidrológicas de pastagens na porção sul da Central Plains dos Estados Unidos. Série solos específico utilizado na instalação são Houston Preto argila (32 monólitos), um Vertisol (údico Haplustert) típico de planícies; Austin (32 monolitos), uma alta carbonate, argila siltosa Mollisol (Udorthentic Haplustol) típico de terras altas; e Bastsil (16 monólitos), um aluvial arenoso Alfisol (údico Paleustalf). O princípio operacional empregado em LYCOG é aproveitar a capacidade fotossintética das plantas para esgotar C A partir de parcelas de ar movido direcionalmente através das câmaras fechadas. O objectivo do tratamento consiste em manter um gradiente linear constante durante o dia em C A a partir de 500 a 250 ul de L-1. Para alcançar este objetivo, LYCOG consiste de duas câmaras lineares, uma câmara superambientes manter a porção do gradiente de 500 para 390 (ambiente) -1 ul L C A, e uma câmara de manutenção a subambient L -1 porção 390 para 250 ul do gradiente. As duas câmaras estão localizados lado a lado, orientado sobre um eixo norte-sul. O gradiente C A é mantido durante a parte do ano, quando a capacidade fotossintética vegetação é adequado; tipicamente desdefinal de abril a início de novembro. As câmaras contêm sensores e instrumentação necessárias para regular o C Um gradiente, controlar a temperatura do ar (T A) para valores próximos dos ambientes, e aplicar quantidades de precipitação uniformes para todos os solos. Os solos são monólitos intactas recolhidas de pradaria Blackland nas proximidades lisímetros de pesagem instalados em hidrologicamente isoladas instrumentados para determinar todos os componentes do balanço hídrico. A água é aplicada em eventos de volume e calendário que aproximar a sazonalidade dos eventos de chuva e de montantes durante um ano médio de precipitação. Assim, LYCOG é capaz de avaliar os efeitos a longo prazo da subambient para superambientes C A e tipo de solo em função do ecossistema pastagem, incluindo água e carbono orçamentos. LYCOG é a terceira geração de C Um gradiente experimentos conduzidos por USDA ARS Pastagem Laboratório de Solo e Água Research. A primeira geração era um protótipo para subambientgradiente ambiente que estabeleceu a viabilidade da abordagem gradiente de 13 e avanço do entendimento das respostas fisiológicas de nível folha de plantas para subambient variação em C Um 14-20. A segunda geração foi uma aplicação no campo escala do conceito de perene C 4 pastagem, com o gradiente estendido para 200-550 mL L -1 21. Este experimento de campo escala forneceu a primeira evidência de que a produtividade da pastagem aumenta com C Um enriquecimento pode saturar perto concentrações atuais ambientes de 20, em parte porque a disponibilidade de nitrogênio podem limitar a produtividade da planta em superambientes C A 22. LYCOG estende esta segunda experiência geração, incorporando solos replicados de diferentes textura, permitindo o teste robusto para efeitos interativos de solos no C Uma resposta das comunidades de pastagem.

<table>
	<tbody>
		<tr>
			<td>Dataloggers, multiplexers</td>
			<td>Campell Scientific, Logan, UT, USA</td>
			<td>CR-7, CR-10, CR-21X, SDM-A04, SDM-CD16AC, AM25T</td>
			<td></td>
		</tr>
		<tr>
			<td>Thermocouples: Copper-constantan</td>
			<td>Omega Engineering, Inc., Stamford, CT, USA</td>
			<td>TT-T-40-SLE, TT-T-24-SLE</td>
			<td></td>
		</tr>
		<tr>
			<td>Quantum sensor</td>
			<td>Li-Cor Biosciences, Lincoln, NE, USA</td>
			<td>LI-190SB</td>
			<td></td>
		</tr>
		<tr>
			<td>CO2/H2O analyzer</td>
			<td>Li-Cor Biosciences, Lincoln, NE, USA</td>
			<td>LI-7000</td>
			<td></td>
		</tr>
		<tr>
			<td>Lysimeter scales</td>
			<td>Avery Weigh-Tronix, Houston, TX, USA</td>
			<td>DSL-3636-10</td>
			<td></td>
		</tr>
		<tr>
			<td>Air sampling pump</td>
			<td>Grace Air Components, Houston, TX, USA</td>
			<td>VP 0660</td>
			<td></td>
		</tr>
		<tr>
			<td>Dew-point generator</td>
			<td>Li-Cor Biosciences, Lincoln, NE, USA</td>
			<td>LI-610</td>
			<td></td>
		</tr>
		<tr>
			<td>Cold water chiller</td>
			<td>AEC Application Engineering, Wood Dale, IL, USA</td>
			<td>CCOA-50</td>
			<td></td>
		</tr>
		<tr>
			<td>Chilled water flow control values</td>
			<td>Belimo Air Controls, Danbury, CT, USA</td>
			<td>LRB24-SR</td>
			<td></td>
		</tr>
		<tr>
			<td>Chilled-water cooling coils</td>
			<td>Coil Company, Paoli, PA, USA</td>
			<td>WC12-C14-329-SCA-R</td>
			<td></td>
		</tr>
		<tr>
			<td>Carbon dioxide refrigerated liquid</td>
			<td>Temple Welding Supply, Temple, TX, USA</td>
			<td>UN2187</td>
			<td></td>
		</tr>
		<tr>
			<td>Polyethylene film</td>
			<td>AT Plastics, Toronto, ON, Canada</td>
			<td>Dura-film Super Dura 4</td>
			<td></td>
		</tr>
		<tr>
			<td>Blower motor/controller</td>
			<td>Dayton Electric, Lake Forest, IL, USA</td>
			<td>2M168C/4Z829</td>
			<td></td>
		</tr>
		<tr>
			<td>Solenoids</td>
			<td>Industrial Automation, Cornelius, NC, USA</td>
			<td>U8256B046V-12/DC</td>
			<td></td>
		</tr>
		<tr>
			<td>Leachate collection pump</td>
			<td>Gast Manufacturing, Benton Harbor, MI, USA</td>
			<td>0523-V191Q-G588DX</td>
			<td></td>
		</tr>
	</tbody>
</table>

a co2 concentration gradient facility for testing co2 enrichment and soil effects on grassland ecosystem function

Contínuo aumento nas concentrações atmosféricas de dióxido de carbono (C) Um mandato técnicas de análise dos impactos sobre os ecossistemas terrestres. A maioria das experiências examinam apenas dois ou alguns níveis de C Uma concentração e um único tipo de solo, mas se a relação C A pode ser variado como um gradiente a partir de subambient para superambientes concentrações em vários solos, pode-se discernir se as respostas dos ecossistemas últimos podem continuar linearmente no futuro e se as respostas podem variar em toda a paisagem. O Lysimeter Dióxido de Carbono Gradiente Facility aplica um 250 a 500 mL L -1 C Um inclinação para Blackland comunidades pradaria plantas estabelecidas em lisímetros contendo argila, argila siltosa, e solos arenosos. O gradiente é criado como fotossíntese por vegetação fechada em em câmaras com temperatura controlada esgota progressivamente o dióxido de carbono do ar que flui direcionalmente através das câmaras. Manter taxa de fluxo de ar adequado, photosy adequadacapacidade nthetic, e controle de temperatura são fundamentais para superar as principais limitações do sistema, que são decrescentes taxas de fotossíntese e aumento do estresse de água durante o verão. A instalação é uma alternativa econômica para outras técnicas de C Um enriquecimento, discerne com sucesso a forma de respostas do ecossistema para subambient para superambientes C Um enriquecimento, e pode ser adaptado para testar interações de dióxido de carbono com outros gases de efeito estufa, como o metano ou ozônio.

Os superambientes e subambient porções do gradiente são mantidos em câmaras separadas (Figura 1). No entanto, ao longo de sete anos de operação (2007 - 2013), as câmaras mantido um gradiente linear em C numa concentração de 500 para 250 ul L-1 (Figura 2), com apenas uma pequena descontinuidade em C A entre a saída das câmaras enriquecidos (Monolith 40) e a entrada da porção de subambient do gradiente (Monolith 41). <p class="jove_content...

Watch this Scientific Journal Video about A CO2 Concentration Gradient Facility for Testing CO2 Enrichment and Soil Effects on Grassland Ecosystem Function at JoVE.com

A CO2 Concentration Gradient Facility for Testing CO2 Enrichment and Soil Effects on Grassland Ecosystem Function

O Lysimeter Dióxido de Carbono Gradiente Facility cria um 250 a 500 mL L -1 gradiente linear de dióxido de carbono em comunidades pastagem câmaras de habitação de plantas com temperatura controlada em argila, argila siltosa, e monólitos de solo arenoso. A facilidade é usada para determinar como os níveis de dióxido de carbono passadas e futuras afetar ciclismo pastagem de carbono.

A CO<sub&gt; 2</sub&gt; Facility Concentração Gradiente para Teste CO<sub&gt; 2</sub&gt; Enriquecimento do solo e efeitos sobre a função da pastagem de Ecossistemas

Continuing increases in atmospheric carbon dioxide concentrations (CA) mandate techniques for examining impacts on terrestrial ecosystems. Most ...

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Environment

A CO2 Concentration Gradient Facility for Testing CO2 Enrichment and Soil Effects on Grassland Ecosystem Function

11.3K visualizações.  Grassland Soil and Water Research Laboratory.  O Lysimeter Dióxido de Carbono Gradiente Facility cria um 250 a 500 mL L -1 gradiente linear de dióxido de carbono em comunidades pastagem câmaras de habitação de plantas com temperatura controlada em argila, argila siltosa, e monólitos de solo arenoso. A facilidade é usada para determinar como os níveis de dióxido de carbono passadas e futuras afetar ciclismo pastagem de carbono. 

Vídeo: A CO2 Concentration Gradient Facility for Testing CO2 Enrichment and Soil Effects on Grassland Ecosystem Function

Design and Operation of a Continuous 13C and 15N Labeling Chamber for Uniform or Differential, Metabolic and Structural, Plant Isotope Labeling

Tracing rare stable isotopes from plant material through the ecosystem provides the most sensitive information about ecosystem processes; from CO2 fluxes and soil organic matter formation to small-scale stable-isotope biomarker probing. Coupling multiple stable isotopes such as 13C with 15N, 18O or&#160;2H has the potential to reveal even more information about complex stoichiometric relationships during biogeochemical transformations. Isotope labeled plant material has been used in various studies of litter decomposition and soil organic matter formation1-4. From these and other studies, however, it has become apparent that structural components of plant material behave differently than metabolic components (i.e. leachable low molecular weight compounds) in terms of microbial utilization and long-term carbon storage5-7. The ability to study structural and metabolic components separately provides a powerful new tool for advancing the forefront of ecosystem biogeochemical studies. Here we describe a method for producing 13C and 15N labeled plant material that is either uniformly labeled throughout the plant or differentially labeled in structural and metabolic plant components.
Here, we present the construction and operation of a continuous 13C and 15N labeling chamber that can be modified to meet various research needs. Uniformly labeled plant material is produced by continuous labeling from seedling to harvest, while differential labeling is achieved by removing the growing plants from the chamber weeks prior to harvest. Representative results from growing Andropogon gerardii Kaw demonstrate the system&#39;s ability to efficiently label plant material at the targeted levels. Through this method we have produced plant material with a 4.4 atom%13C and 6.7 atom%15N uniform plant label, or material that is differentially labeled by up to 1.29 atom%13C and 0.56 atom%15N in its metabolic and structural components (hot water extractable and hot water residual components, respectively). Challenges lie in maintaining proper temperature, humidity, CO2 concentration,&#160;and light levels in an airtight 13C-CO2 atmosphere for successful plant production. This chamber description represents a useful research tool to effectively produce uniformly or differentially multi-isotope labeled plant material for use in experiments on ecosystem biogeochemical cycling.

Design and Operation of a Continuous 13C and 15N Labeling Chamber for Uniform or Differential, Metabolic and Structural, Plant Isotope Labeling

This method explains how to build and operate a continuous 13C and 15N isotope labeling chamber for uniform or differential plant tissue labeling. Representative results from metabolic and structural labeling of Andropogon gerardii are discussed.

Projeto e operação de uma contínua<sup&gt; 13</sup&gt; C e<sup&gt; 15</sup&gt; N Labeling Câmara de uniforme ou Diferencial, metabólica e estrutural, Fábrica de Marcação por Isótopo

Tracing rare stable isotopes from plant material through the ecosystem provides the most sensitive information about ecosystem processes; from CO2 fluxes ...

Ambiente

Design and Construction of an Urban Runoff Research Facility

As the urban population increases, so does the area of irrigated urban landscape. Summer water use in urban areas can be 2-3x winter base line water use due to increased demand for landscape irrigation. Improper irrigation practices and large rainfall events can result in runoff from urban landscapes which has potential to carry nutrients and sediments into local streams and lakes where they may contribute to eutrophication. A 1,000 m2 facility was constructed which consists of 24 individual 33.6 m2 field plots, each equipped for measuring total runoff volumes with time and collection of runoff subsamples at selected intervals for quantification of chemical constituents in the runoff water from simulated urban landscapes. Runoff volumes from the first and second trials had coefficient of variability (CV) values of 38.2 and 28.7%, respectively. CV values for runoff pH, EC, and Na concentration for both trials were all under 10%. Concentrations of DOC, TDN, DON, PO4-P, K+, Mg2+, and Ca2+ had CV values less than 50% in both trials. Overall, the results of testing performed after sod installation at the facility indicated good uniformity between plots for runoff volumes and chemical constituents. The large plot size is sufficient to include much of the natural variability and therefore provides better simulation of urban landscape ecosystems.

This paper describes the design, construction, and function of a 1,000 m2 facility containing 24 individual 33.6 m2 field plots equipped for measuring total runoff volumes with time and collection of runoff subsamples at selected intervals for quantification of chemical constituents in the runoff water from simulated home lawns.

Projeto e Construção de um Mecanismo de Pesquisa escoamento urbano

As the urban population increases, so does the area of irrigated urban landscape. Summer water use in urban areas can be 2-3x winter base line water use ...

Measuring Carbon-based Contaminant Mineralization Using Combined CO2 Flux and Radiocarbon Analyses

A method is described which uses the absence of radiocarbon in industrial chemicals and fuels made from petroleum feedstocks which frequently contaminate the environment. This radiocarbon signal &#8212; or rather the absence of signal &#8212; is evenly distributed throughout a contaminant source pool (unlike an added tracer) and is not impacted by biological, chemical or physical processes (e.g., the 14C radioactive decay rate is immutable). If the fossil-derived contaminant is fully degraded to CO2, a harmless end-product, that CO2 will contain no radiocarbon. CO2 derived from natural organic matter (NOM) degradation will reflect the NOM radiocarbon content (usually &#60;30,000 years old). Given a known radiocarbon content for NOM (a site background), a two end-member mixing model can be used to determine the CO2 derived from a fossil source in a given soil gas or groundwater sample. Coupling the percent CO2 derived from the contaminant with the CO2 respiration rate provides an estimate for the total amount of contaminant degraded per unit time. Finally, determining a zone of influence (ZOI) representing the volume from which site CO2 is collected allows determining the contaminant degradation per unit time and volume. Along with estimates for total contaminant mass, this can ultimately be used to calculate time-to-remediate or otherwise used by site managers for decision-making.

Measuring Carbon-based Contaminant Mineralization Using Combined CO2 Flux and Radiocarbon Analyses

A protocol is described wherein CO2 mineralized from organic contaminant (derived from petroleum feedstocks) biodegradation is trapped, quantified, and analyzed for 14C content. A model is developed to determine CO2 capture zone's spatial extent. Spatial and temporal measurements allow integrating contaminant mineralization rates for predicting remediation extent and time.

Medindo-carbono com base Contaminant Mineralização Usando Combinada CO<sub&gt; 2</sub&gt; fluxo e de radiocarbono Análises

A method is described which uses the absence of radiocarbon in industrial chemicals and fuels made from petroleum feedstocks which frequently contaminate ...

A Protocol for Collecting and Constructing Soil Core Lysimeters

Leaching of nutrients from land applied fertilizers and manure used in agriculture can lead to accelerated eutrophication of surface water. Because the landscape has complex and varied soil morphology, an accompanying disparity in flow paths for leachate through the soil macropore and matrix structure is present. The rate of flow through these paths is further affected by antecedent soil moisture. Lysimeters are used to quantify flow rate, volume of water and concentration of nutrients leaching downward through soils. While many lysimeter designs exist, accurately determining the volume of water and mass balance of nutrients is best accomplished with bounded lysimeters that leave the natural soil structure intact. 
Here we present a detailed method for the extraction and construction of soil core lysimeters equipped with soil moisture sensors at 5 cm and 25 cm depths. Lysimeters from four different Coastal Plain soils (Bojac, Evesboro, Quindocqua and Sassafras) were collected on the Delmarva Peninsula and moved to an indoor climate controlled facility. Soils were irrigated once weekly with the equivalent of 2 cm of rainfall to draw down soil nitrate-N concentrations. At the end of the draw down period, poultry litter was applied (162 kg TN ha-1) and leaching was resumed for an additional five weeks. Total recovery of applied irrigation water varied from 71% to 85%. Nitrate-N concentration varied over the course of the study from an average of 27.1 mg L-1 before litter application to 40.3 mg L-1 following litter application. While greatest flux of nutrients was measured in soils dominated by coarse sand (Sassafras) the greatest immediate flux occurred from the finest textured soil with pronounced macropore development (Quindocqua).

A detailed method for extraction and assembly of intact soil core lysimeters and their use for study of leachate and associated loss of nutrients from surface applied poultry litter is demonstrated.

Um Protocolo de Coleta e Construindo lisímetros amostra de solo

Leaching of nutrients from land applied fertilizers and manure used in agriculture can lead to accelerated eutrophication of surface water. Because the ...

Soil Lysimeter Excavation for Coupled Hydrological, Geochemical, and Microbiological Investigations

Studying co-evolution of hydrological and biogeochemical processes in the subsurface of natural landscapes can enhance the understanding of coupled Earth-system processes. Such knowledge is imperative in improving predictions of hydro-biogeochemical cycles, especially under climate change scenarios. We present an experimental method, designed to capture sub-surface heterogeneity of an initially homogeneous soil system. This method is based on destructive sampling of a soil lysimeter designed to simulate a small-scale hillslope. A weighing lysimeter of one cubic meter capacity was divided into sections (voxels) and was excavated layer-by-layer, with sub samples being collected from each voxel. The excavation procedure was aimed at detecting the incipient heterogeneity of the system by focusing on the spatial assessment of hydrological, geochemical, and microbiological properties of the soil. Representative results of a few physicochemical variables tested show the development of heterogeneity. Additional work to test interactions between hydrological, geochemical, and microbiological signatures is planned to interpret the observed patterns. Our study also demonstrates the possibility of carrying out similar excavations in order to observe and quantify different aspects of soil-development under varying environmental conditions and scale.

This study presents an excavation method for investigating subsurface hydrological, geochemical, and microbiological heterogeneity of a soil lysimeter. The lysimeter simulates an artificial hillslope which was initially under homogeneous condition and had been subjected to approximately 5,000 mm of water over eight cycles of irrigation in an 18-month period.

Monólito escavação para Coupled Hidrológicos, geoquímicos e microbiológicos Investigações

Studying co-evolution of hydrological and biogeochemical processes in the subsurface of natural landscapes can enhance the understanding of coupled ...

Measurement of the Rheology of Crude Oil in Equilibrium with CO2 at Reservoir Conditions

A rheometer system to measure the rheology of crude oil in equilibrium with carbon dioxide (CO2) at high temperatures and pressures is described. The system comprises a high-pressure rheometer which is connected to a circulation loop. The rheometer has a rotational flow-through measurement cell with two alternative geometries: coaxial cylinder and double gap. The circulation loop contains a mixer, to bring the crude oil sample into equilibrium with CO2, and a gear pump that transports the mixture from the mixer to the rheometer and recycles it back to the mixer. The CO2 and crude oil are brought to equilibrium by stirring and circulation and the rheology of the saturated mixture is measured by the rheometer. The system is used to measure the rheological properties of Zuata crude oil (and its toluene dilution) in equilibrium with CO2 at elevated pressures up to 220 bar and a temperature of 50 &#176;C. The results show that CO2 addition changes the oil rheology significantly, initially reducing the viscosity as the CO2 pressure is increased and then increasing the viscosity above a threshold pressure. The non-Newtonian response of the crude is also seen to change with the addition of CO2.

Measurement of the Rheology of Crude Oil in Equilibrium with CO2 at Reservoir Conditions

A method for measuring the rheology of crude oil in equilibrium with carbon dioxide at reservoir conditions is presented.

Medição da reologia do petróleo bruto em equilíbrio com CO<sub&gt; 2</sub&gt; Nas condições do reservatório

A rheometer system to measure the rheology of crude oil in equilibrium with carbon dioxide (CO2) at high temperatures and pressures is described. The ...

Measuring and Mapping Patterns of Soil Erosion and Deposition Related to Soil Carbonate Concentrations Under Agricultural Management

Spatial patterns of soil erosion and deposition can be inferred from differences in ground elevation mapped at appropriate time increments. Such changes in elevation are related to changes in near-surface soil carbonate (CaCO3) profiles. The objective is to describe a simple conceptual model and detailed protocol for repeatable field and laboratory measurements of these quantities. Here, accurate elevation is measured using a ground-based differential global positioning system (GPS); other data acquisition methods could be applied to the same basic method. Soil samples are collected from prescribed depth intervals and analyzed in the lab using an efficient and precise modified pressure-calcimeter method for quantitative analysis of inorganic carbon concentration. Standard statistical methods are applied to point data, and representative results show significant correlations between changes in soil surface layer CaCO3 and changes in elevation consistent with the conceptual model; CaCO3 generally decreased in depositional areas and increased in erosional areas. Maps are derived from point measurements of elevation and soil CaCO3 to aid analyses. A map of erosional and depositional patterns at the study site, a rain-fed winter wheat field cropped in alternating wheat-fallow strips, shows the interacting effects of water and wind erosion affected by management and topography. Alternative sampling methods and depth intervals are discussed and recommended for future work relating soil erosion and deposition to soil CaCO3.

Spatial patterns of soil erosion and deposition can be inferred from differences in ground elevation mapped at appropriate time increments. Such changes in elevation are related to changes in near-surface soil carbonates. Repeatable methods for field and laboratory measurements of these quantities and data analysis methods are described here.

Medição e mapeamento de padrões de erosão e deposição relacionadas às concentrações de carbonato de solo sob gestão agrícola

Spatial patterns of soil erosion and deposition can be inferred from differences in ground elevation mapped at appropriate time increments. Such changes ...

Wastewater Irrigation Impacts on Soil Hydraulic Conductivity: Coupled Field Sampling and Laboratory Determination of Saturated Hydraulic Conductivity

Since the early 1960s, an alternative wastewater discharge practice at The Pennsylvania State University has been researched and its impacts monitored. Rather than discharging treated wastewater to a stream, and thereby directly impacting the stream quality, the effluent is applied to forested and cropped land managed by the University. Concerns related to reductions in soil hydraulic conductivity occur when considering wastewater reuse. The methodology described in this manuscript, matching soil sample size with the size of the laboratory-based hydraulic conductivity measurement apparatus, provides the benefits of a relatively rapid collection of samples with the benefits of controlled laboratory boundary conditions. The results suggest that there may have been some impact of wastewater reuse on the soil&#39;s ability to transmit water at deeper depths in the depressional areas of the site. Most of the reductions in the soil hydraulic conductivity in the depressions appear to be related to the depth from which the sample was collected, and by inference, associated with the soil structural and textural differences.

Here we present a methodology which matches a soil sample size and a hydraulic conductivity measurement device to prevent the so-called wall flow along the inside of the soil container from being erroneously included in water flow measurements. Its use is demonstrated with samples collected from a wastewater irrigation site.

Impactos de irrigação de efluentes na condutividade hidráulica do solo: acoplado a amostragem de campo e laboratório determinação da condutividade hidráulica saturada

Since the early 1960s, an alternative wastewater discharge practice at The Pennsylvania State University has been researched and its impacts monitored. ...

Evaluating Dryocosmus Kuriphilus-induced Damage on Castanea Sativa

Dryocosmus kuriphilus Yasumatsu has become a major pest for Castaneasativa since its arrival in Europe. Its galling activity results in the formation of different gall types and prevents the development of normal shoots. Repeated and uncontrolled attacks cause, besides the production of galls and the attendant gall-related reduction in leaf area, progressive corruption of the branch architecture, including the death of branch parts, and an increase in dormant bud activation. Thus far, there have been few attempts to quantify branch architecture damage. Further, the different methods for assessing infestation degree (MAID) that have been developed focus only on the galls' presence and abundance.
Using the leaf area to sapwood area relationship as a green biomass indicator, we developed in a previous study a damage composite index (DCI) that takes into account the most important branch architectural features, allowing for realistic damage assessment during the entire epidemic process. 
The aim of this study is to present this novel method and highlight differences in the damage description with respect to other broadly used indices. Results show how the DCI depicts branch damage better, especially during the epidemic peak, compared to MAID, which tend to underestimate it. We conclude by suggesting how to properly evaluate the overall impact of the pest by means of our composite damage index, the infestation degree using classic methods, and crown transparency evaluations.

Evaluating Dryocosmus Kuriphilus-induced Damage on Castanea Sativa

It is common practice to assess the damage caused by Dryocosmus kuriphilus by considering the abundance of galls alone rather than by also taking related branch corruption into consideration. We propose a composite damage index that takes into account the most important branch features, thus enabling more realistic damage assessment.

Avaliando Dryocosmus Kuriphilus-induzido por danos em Castanea Sativa

Dryocosmus kuriphilus Yasumatsu has become a major pest for Castaneasativa since its arrival in Europe. Its galling activity results in the formation of ...

A Uniaxial Compression Experiment with CO2-Bearing Coal Using a Visualized and Constant-Volume Gas-Solid Coupling Test System

Injecting carbon dioxide (CO2) into a deep coal seam is of great significance for reducing the concentration of greenhouse gases in the atmosphere and increasing the recovery of coalbed methane. A visualized and constant-volume gas-solid coupling system is introduced here to investigate the influence of CO2 sorption on the physical and mechanical properties of coal. Being able to keep a constant volume and monitor the sample using a camera, this system offers the potential to improve instrument accuracy and analyze fracture evolution with a fractal geometry method. This paper provides all steps to perform a uniaxial compression experiment with a briquette sample in different CO2 pressures with the gas-solid coupling test system. A briquette, cold-pressed by raw coal and sodium humate cement, is loaded in high-pressure CO2, and its surface is monitored in real-time using a camera. However, the similarity between the briquette and the raw coal still needs improvement, and a flammable gas such as methane (CH4) cannot be injected for the test. The results show that CO2 sorption leads to peak strength and elastic modulus reduction of the briquette, and the fracture evolution of the briquette in a failure state indicates fractal characteristics. The strength, elastic modulus, and fractal dimension are all correlated with CO2 pressure but not with a linear correlation. The visualized and constant-volume gas-solid coupling test system can serve as a platform for experimental research about rock mechanics considering the multifield coupling effect.

A Uniaxial Compression Experiment with CO2-Bearing Coal Using a Visualized and Constant-Volume Gas-Solid Coupling Test System

This protocol demonstrates how to prepare a briquette sample and conduct a uniaxial compression experiment with a briquette in different CO2 pressures using a visualized and constant-volume gas-solid coupling test system. It also aims to investigate changes in terms of coal&#8217;s physical and mechanical properties induced by CO2 adsorption.

Um experimento de compactação uniaxial com carvão de rolamento de CO2usando um sistema de teste de acoplamento de gás sólido de volume visualizado e constante

Injecting carbon dioxide (CO2) into a deep coal seam is of great significance for reducing the concentration of greenhouse gases in the atmosphere and ...