A incidência das falsas memórias no processo penal

OpenAIRE

Pritsch, Fabiane Romanzini

2017-01-01

O objeto precípuo deste trabalho monográfco é a análise da incidência do fenômeno psicológico das falsas memórias na produção da prova testemunhal no processo penal. Para tanto, adotou-se o método de abordagem dedutivo, bem como as técnicas bibliográfca e documental. O Estado, por ser o titular exclusivo do jus puniendi, é o responsável por impor uma sanção quando constatar a prática de um crime. Contudo, referida medida somente poderá ser aplicada se houver a instauração de um processo, inst...

Outbreak of canine visceral leishmaniasis in Barra Mansa, State of Rio de Janeiro

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Cintia Xavier de Mello

2014-12-01

Full Text Available Introduction In Brazil, visceral leishmaniasis (VL has spread to various regions. This study reports canine cases of VL in Barra Mansa, where human VL cases were recently reported. Methods Using the human index case, a canine survey was performed by dual-path platform immunochromatography and enzyme-linked immunosorbent assay. Seropositive animals were euthanized. Cultures were collected to detect Leishmania parasites. Results Serological tests detected 141 canine VL cases, and Leishmania chagasi were isolated from 82.2% animals. Conclusions Leishmania chagasi is in circulation in Barra Mansa. This study broadens information on the parasite's distribution in the State of Rio de Janeiro.

Barras de fútbol, consumo de drogas y violencia

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Nicolás Ignacio Uribe Aramburo

2014-01-01

Full Text Available A partir de una investigación descriptiva y analítica, con un diseño metodológico cualitativo, se describen y analizan la coocurrencia entre el consumo de sustancias psicoactivas y los comportamientos agre - sivos y violentos en miembros de algunas de las barras de fútbol de la ciudad de Medellín, Colombia. Mediante la técnica de observación participante se muestra que el consumo de drogas, junto con los fe - nómenos de la identificación, la sugestión y el contagio social, pueden promover la alteración de la conciencia y la abolición temporal de los patrones de pensamiento y comportamiento típicos de los individuos, así como de los preceptos morales y éticos que regulan la actuación en sociedad. Se explica por qué los individuos de la masa (barra de fútbol se vuelven irreflexivos, impulsivos, iracundos y violentos, desde perspectivas de la psicología social, el psicoanálisis y la etología.

Sintaxe X-barra: uma aplicação computacional

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Gabriel de Ávila Othero

2009-04-01

Full Text Available http://dx.doi.org/10.5007/1984-8420.2008v9nespp15 Neste trabalho, apresentaremos uma aplicação computacional da teoria X-barra (cf. HAEGEMAN, 1994; MIOTO et al., 2004, através do programa Grammar Play, um parser sintático em Prolog. O Grammar Play analisa sentenças declarativas simples do português brasileiro, identificando sua estrutura de constituintes. Sua gramática é implementada em Prolog, com o recurso das DCGs, e é baseada nos moldes propostos pela teoria X-barra. O parser é uma primeira tentativa de expandir a cobertura de analisadores semelhantes, como o esboçado em Pagani (2004 e Othero (2004. Os objetivos que guiam a presente versão do Grammar Play são o de implementar computacionalmente modelos lingüísticos coerentes aplicados à descrição do português e o de criar uma ferramenta computacional que possa ser usada didaticamente em aulas de introdução à sintaxe e lingüística, por exemplo.

AVANCES EN LA TECNOLOGIA DE EW DE COBRE: BARRAS INTERCALADAS SEGMENTADAS.

OpenAIRE

VIDAL RUDLOFF, GUILLERMO A.; VIDAL RUDLOFF, GUILLERMO A.

2005-01-01

Esta tesis presenta la tecnología de barras intercelda segmentadas para los procesos electrometalúrgicos de cobre, aplicable en electroobtención y en electrorefinación. En estos procesos, la densidad de corriente real de cada electrodo difiere de la densi 126p.

El rumor del nopal chino: construcción institucional y efectos sociales de noticias falsas

OpenAIRE

BRUNO LUTZ; ALEXANDER PADILLA

2012-01-01

Este artículo es el resultado de una investigación sociológica sobre la noticia falsa que circuló a nivel nacional y en Milpa Alta, al sur de la Ciudad de México. Al examinar las diferentes versiones del rumor periodístico de la importación de nopal chino a México, logramos mostrar cómo se articularon los intereses inmediatos de los agentes colectivos implicados, con temáticas de corte histórico, racial, y económico.

Trilha ecológica do Cavalo-Marinho: Ecoturismo em Barra Grande/PI

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Andrea Geisa Pereira Barbosa

2010-06-01

Full Text Available Na comunidade Barra Grande, localidade do município de Cajueiro da Praia - PI existe uma trilha ecológica muito bem planejada pelos moradores locais da própria comunidade: A Trilha do Cavalo - Marinho. Essa trilha consiste em um passeio ecológico, onde se trabalham comutantemente o turismo, a sustentabilidade e a educação ambiental.  A área de estudo - a localidade Barra Grande - pertence à Área de Proteção Ambiental (APA do Delta do Parnaíba (APA do Delta do Parnaíba, que visa proteger os ecossistemas costeiros, localizados nos estados do Maranhão, Piauí e Ceará. A referente pesquisa tem como principal objetivo inter-relacionar o termo ecoturismo, educação ambiental, sustentabilidade, e a trilha do cavalo marinho, realizado na pequena localidade do Piauí, Barra Grande. A metodologia utilizada no trabalho em estudo foi pesquisa bibliográfica: constituída de um conjunto de obras escritas referente ao turismo, desenvolvimento sustentável, desenvolvimento local sustentável, meio ambiente e educação ambiental e pesquisa de campo não participativa: realizada para obtenção das informações sobre a situação da área de estudo e analisar os aspectos trabalhados pelos moradores tanto na questão de educação ambiental como da sustentabilidade.

Aceitabilidade de barra de cereais potencialmente probiótica

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Gustavo Almeida Bastos

2014-06-01

Full Text Available A utilização de micro-organismos probióticos é uma das mais atrativas opções para consumo humano, devido às suas excelentes propriedades funcionais. Considerando-se que o desenvolvimento de novos produtos tem adquirido crescente importância, objetivou-se, neste trabalho, avaliar a aceitabilidade de barras de cereais com micro-organismos potencialmente probióticos. Utilizou-se a escala hedônica estruturada de nove pontos, que contém os termos descritivos situados entre "gostei extremamente" e "desgostei extremamente". Os atributos avaliados foram: aparência, textura, sabor e impressão global. Foi também realizada uma pesquisa de intenção de consumo, utilizando-se uma escala de cinco pontos situados entre "nunca comeria" e "comeria sempre". A avaliação sensorial foi realizada por uma equipe de 36 indivíduos não treinados: professores, estudantes e funcionários da Universidade Federal do Espírito Santo, de ambos os sexos, com idades entre 20 e 40 anos. As amostras foram apresentadas aos provadores em ordem aleatória, de forma monádica, devidamente identificadas com números de três dígitos. A utilização da levedura Saccharomyces boulardii e da bactéria Lactobacillus acidophilus, por meio das diferentes formas de incorporação nas barras de cereais, não interferiu na qualidade sensorial e estrutural do produto. As quatro formulações de barra de cereais apresentaram boa aceitação sensorial quanto a aparência, textura, sabor e impressão global. A pesquisa de intenção de consumo revelou que mais de 60% dos provadores consumiriam o produto sempre ou frequentemente. A viabilidade dos micro-organismos por curto período de tempo torna necessária a realização de novos estudos, com o objetivo de aumentar a estabilidade destes micro-organismos durante a vida de prateleira do produto.

O efeito da sugestão de falsa informação para eventos emocionais: quão suscetíveis são nossas memórias?

OpenAIRE

Neufeld,Carmem Beatriz; Brust,Priscila Goergen; Stein,Lilian Milnitsky

2008-01-01

O presente trabalho visa fornecer evidências científicas da susceptibilidade das memórias a distorção através do estudo das falsas memórias (lembranças de eventos que, na realidade, não ocorreram) para situações emocionalmente carregadas. Foi usada a versão brasileira dos instrumentos e procedimentos de Cahill, Prins, Weber, e McGaugh e adaptada por Neufeld, Brust e Stein para a investigação do efeito da emoção na memória e nas falsas memórias. O experimento investigou o efeito de sugestão de...

OBTENÇÃO DE BARRAS DE CEREAIS DE CAJU AMEIXA COM ALTO TEOR DE FIBRAS

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LUíSA HELENA ELLERY MOUR�O

2010-03-01

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As barras de cereais vêm apresentando crescimento constante junto ao público consumidor. Considerando o crescimento do segmento de barras de cereais no setor de alimentos este trabalho teve como objetivos desenvolver barras de cereais de caju ameixa com alto teor de fi bras utilizando ingredientes funcionais e matéria-prima regional; inovar no uso de ingredientes não utilizados nas formulações convencionais; realizar análises físicas, físicoquímicas e químicas e avaliar as propriedades nutricionais. Formulou-se dois tipos de barras, (F1 e (F2 a partir de uma formulação básica (FB. A FB foi processada utilizando-se aveia, fl ocos de arroz, leite em pó desnatado, açúcar mascavo, glucose de milho, gordura vegetal hidrogenada, canela, lecitina de soja e fl ocos de milho. As formulações F1 e F2 diferiram da FB nas concentrações dos ingredientes, na adição de linhaça, de caju ameixa, de castanha de caju, na substituição da gordura vegetal hidrogenada por óleo de canola e na retirada dos fl ocos de milho. A FB resultou 94,39 kcal e F1 e F2 em 95,69 kcal e 101,06 kcal respectivamente em 25g utilizando os coefi cientes de ATWATER. A modifi - cação dos ingredientes provocou aumento signifi cativo no teor de fi bra alimentar tornando as barras F1 e F2 produtos com alto teor de fi bra alimentar (10,58g e 12,69g/100g, respectivamente. Conclui-se que as barras de cereais F1 e F2 podem ser indicadas para indivíduos com constipação intestinal, dislipidemias e sobrepeso. Além disso, ambas poderiam ser enquadradas no conceito de alimento funcional, devido ao fato de conterem um maior teor de fi bras dietéticas que contribuem para a manutenção da boa saúde.

Diseño de una máquina de figuración de barras de acero de refuerzo para hormigón armado

OpenAIRE

Palacios Flores, Carlos Pablo

2011-01-01

El diseño de la máquina dobladora de barras de acero utilizado para el refuerzo de hormigón construcciones tiene el propósito de reducir la mano de obra y aumentar el tiempo de producción. lo también está destinado a mejorar la calidad de la flexión en las barras que actualmente se realizan. Como los dobladores manuales, dobladoras mecánicas también doblar barras de alrededor de una matriz, pero la proceso de plegado mecánico se convierte en automático. Esto permite utilizar 42 (60) grados...

CÓDIGOS DE BARRAS DE LA VIDA: INTRODUCCIÓN Y PERSPECTIVA

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Andrew J. Crawford

2011-09-01

Full Text Available RESUMEN Los códigos de barra de ADN representan una iniciativa global para acumular cortas secuencias estandarizadas de ADN de la gran mayoría de las especies de eucariotas del planeta, con el propósito de facilitar la identificación y conocimiento de la biodiversidad. Después de ocho años de discusión y producción en la literatura científica, el tema sigue generando controversia, debido en parte a la falta de homogeneidad en la definición y el alcance del método entre los autores. En este artículo enfatizamos la definición y metodología de los códigos de barra de ADN, así como su uso para contestar preguntas nuevas en el campo de la ecología, la evolución y la conservación. Palabras clave: Bases de datos, Bioinformática, Códigos de barras de ADN, Diagnosis molecular, Sistemática filogenética, Genética evolutiva, Taxonomía. ABSTRACT DNA barcode of life is a global initiative to populate a global database of short, standardized DNA fragments from most eukaryotic species to facilitate the identification and understanding of the world’s biodiversity. In the eight years following its proposal, the topic of DNA barcoding remains controversial in the scientific literature due, in part, to a lack of consensus on how DNA barcoding is defined and what activities are included under this title. In the present paper we review the definition, methods and goals of DNA barcoding, and highlight how data generated by various DNA barcode of life campaigns may also be used to address fundamental and novel questions in ecology, evolution and conservation. Keywords: Bioinformatics, Databases, DNA barcode of life, Evolutionary genetics, Molecular diagnosis, Phylogenetic systematics, Taxonomy.

DEFICIÊNCIA DE COBALTO EM BOVINOS EM BARRA DO GARÇA – ESTADO DO MATO GROSSO COBALT DEFICIENCY IN BOVINES IN BARRA DO GARÇA, MATO GROSSO STATE, BRAZIL

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Fernando Melgaço da Costa

2007-09-01

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O presente trabalho relata o diagnóstico da deficiência de cobalto em 2 bezerros mestiços de nelore, provenientes de Barra do Garça, Distrito de Xavantina—MT. As alterações clínicas e resultados laboratoriais encontrados permitiram o diagnóstico que foi confirmado pelo resultado do tratamento empregado com sulfato de cobalto e Vitamina B12. Alterações macro e microscópicas foram determinadas em um dos animais.

This paper describes the diagnosis of cobalt deficiency in two Nelore claves from Barra do Garça, district of Xavantina - MT. The diagnosis was possible through clinical and laboratory results, and was confirmed by the treatment with cobalt sulphate and B12 vitamin. The macro and microscopical changes presented in the dead animal are also described in this paper.

Benchmarking BarraCUDA on Epigenetic DNA and nVidia Pascal GPUs

OpenAIRE

Langdon, W

2016-01-01

Typically BarraCUDA uses CUDA graphics cards to map DNA reads to the human genome. Previously its software source code was genetically improved for short paired end next generation sequences. On longer, 150 base paired end noisy Cambridge Epigenetix's data, a Pascal GTX 1080 processes about 10000 strings per second, comparable with twin nVidia Tesla K40.

Fauna de mamíferos del yacimiento costero de Herriko Barra (Zarautz, País Vasco).

OpenAIRE

K. Mariezkurrena; J. Altuna

1995-01-01

Se cuenta de los restos de Mamíferos hallados en el yacimiento costero al aire libre de Herriko Barra (Zarautz, País Vasco), formado durante el Holoceno (C14:5.810 +170 BP). Aunque algunos elementos de la industria lítica apuntan hacia una tipología neolítica, la economía de los pobladores de Herriko   Barra era mesolítica, ya que no hay ningún indicio de domesticación animal ni de agricultura. La inmensa mayoría de los restos son de ciervo (92,2%). El resto está compuesto por restos de corz...

Análisis cinemático de la trayectoria de la barra en la Arrancada y su relación con el rendimiento

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José Campos Granell

2009-06-01

Full Text Available El objetivo de este estudio está centrado en la descripción de la trayectoria de la barra en la Arrancada, así como analizar las diferencias entre levantadores de diferente nivel de rendimiento en términos relativos, incorporando como elemento de análisis el desplazamiento de los pies. La muestra está formada por 31 levantadores de categoría masculina de diferentes categorías de peso. Para el estudio comparativo se conforman dos grupos de levantadores en función de la carga relativa, esto es, la carga máxima levantada en función del peso corporal. Se utiliza la metodología Fotogrametría 3D. Los resultados revelan que los levantadores que consiguen una mayor carga relativa desplazan la barra siguiendo una trayectoria más vertical. Estas diferencias se concretan en un menor desplazamiento horizontal de la barra en el instante en que la barra alcanza la máxima elevación y en el instante del encaje (p: 0,030 y p: 0,005, respectivamente y en un menor desplazamiento atrás de los pies (p: 0,012. No se han encontrado diferencias en el recorrido vertical de la barra. Estos hallazgos podrían ser tenidos en cuenta en el entrenamiento individualizado de los levantadores, especialmente de los más jóvenes.

Diagnosis and analysis of water quality and trophic state of Barra Bonita reservoir, SP

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Giovanna Moreti Buzelli

2013-04-01

Full Text Available As a consequence of the intensification of environmental degradation, we observed a decrease in water availability and a change in water quality. Therefore, the integrated management of watersheds is an issue of extreme importance. Limnological monitoring is an important tool for environmental management, providing information on the quality of inland waters and indicating the main factors responsible for the degradation of water resources. The Barra Bonita reservoir is located in the central region of São Paulo State, in the Superior Middle Tietê Basin, and the adjacent areas of the reservoir are subject to several human activities potentially impacting the environment. In this context, there is a need to determine the nature of negative human impacts on water resources. The present study aimed to analyze and diagnose the water quality of Barra Bonita reservoir using the water quality index (WQI and the trophic state index (TSI. To this end, measurements of specific limnological variables were made in situ and laboratory and an analysis of data from CETESB annual reports was conducted. The results found that the waters of the reservoir were relatively healthy, but hyper eutrophic for the period from2007 to 2012, indicating the importance of environmental management for the restoration and preservation of natural resources in this region. The estimated indices and the land use map of adjacent areas of the Barra Bonita reservoir showed that agriculture was the largest category of land use and that it contributes directly to the degradation of water quality due to contamination by run-off from fertilizers.

Variación temporal y espacial de aves playeras en la laguna Barra de Navidad, Jalisco, en tres temporadas no reproductivas

OpenAIRE

Salvador Hernández; Sergio Serrano; Xóchitl A. Hernández; María Isabel Robles

2012-01-01

Hay un escaso conocimiento de las aves playeras en los humedales costeros de Jalisco, y en particular en la laguna Barra de Navidad. El presente trabajo contribuye al conocimiento de este grupo de aves y describe su distribución temporal y espacial en la laguna Barra de Navidad durante tres temporadas no reproductivas (1999-2000, 2006-2007 y 2008-2009). Se realizaron censos mensuales de noviembre-abril en las tres temporadas con el fin de registrar todas las especies de aves playeras. Se iden...

Diversidade e potencial biotecnólogico de fungos filamentosos isolados do manguezal Barra das Jangadas, Jaboatão dos Guararapes, Pernambuco

OpenAIRE

Neto Ferreira Gomes, Daniela

2007-01-01

Fungos filamentosos de sedimento do manguezal Barra das Jangadas, foram isolados e identificados com objetivo de proceder a caracterização enzimática. Foram coletadas amostras de sedimento do manguezal Barra das Jangadas nos meses de março e abril/2004 e outubro/2005 (período de estiagem); junho e julho/2004 e julho/2005 (período chuvoso). As coletas foram realizadas em quatro pontos em manguezais do estuário formado pelos rios Jaboatão e Pirapama, perfazendo um total de 24 ...

CARACTERÍSTICAS FÍSICO-QUÍMICAS DA AMÊNDOA DE MACAÚBA E SEU APROVEITAMENTO NA ELABORAÇÃO DE BARRAS DE CEREAIS

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Nísia Andrade Villela DESSIMONI-PINTO

2010-09-01

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A amêndoa de macaúba (Acrocomia aculeata (Jacq. Lodd. tem despertado grande interesse socio-econômico para a população do Cerrado e possui propriedades nutricionais pouco estudadas. O objetivo deste estudo foi caracterizar físico-quimicamente a amêndoa de macaúba e verifi car o valor nutricional e a aceitabilidade de uma barra de cereais elaborada a partir deste material. Os frutos coletados foram lavados, sanitizados, secos e suas amêndoas foram retiradas. As características físico-químicas das amêndoas avaliadas foram massa, diâmetro, pH, SST, ATT e composição centesimal. Elaborou-se uma barra de cereais teste com adição de 15% do fruto e uma controle e determinou-se suas composições centesimais. A avaliação sensorial das formulações foi realizada com 45 participantes em três etapas: teste de aceitação (escala de 5 pontos, teste de preferência e análise descritiva quantitativa (aparência, cor, aroma, sabor, textura e doçura dos produtos. As amêndoas de macaúba estudadas possuem quantidades expressivas de lipídios (29,73%, proteínas (12,28% e energia (524,19kcal/100g. A barra de cereais com macaúba obteve maiores teores de lipídios (7,84% e energia (396,28kcal/100g. O índice de aceitação da barra de cereais formulada com macaúba foi de 88,90% e o teste de preferência evidenciou 71,11% de aprovação pelos participantes da pesquisa. A barra teste obteve atributos mais bem aceitos em relação à controle (p<0,05, na qual o atributo “sabor” alcançou a maior pontuação média (4,62. Dessa forma, conclui-se que as características físico-químicas da amêndoa de macaúba contribuem de forma positiva para a elaboração de barras de cereais, conferindo ao produto final um perfil sensorial de boa aceitabilidade.

Estructuras espaciales de barras desplegables

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Escrig, Félix

1984-11-01

Full Text Available From simple expandable plane structures, as the articulated crosses at their midpoint could be, we have established a succession of spacial combinations of growing complexity, with the same conditions of foldability as the original elements. By means of a rational methodology of joints, similar to those used in conventional spatial frame structures, several types of expandable structures had been defined in a classification which intends to be complete and could be resumed in four basical types. These types, moreover, could have a linear, a plane or a spatial growing, increasing formal possibilities and practical uses. If original crosses have any irregularity as excentric joints, struts of different length, more than one intermediate joint or of different size, a distortion of the generated systems, referred above, is produced, which should give us shapes of huge architectural utility. In these cases crosses must be of compatible length to make possible the folding process. Some constructive solutions for joints and for folding and expanding mechanisms are also shown. Finally, we have introduced a short reference to the working way of these structures as well as the stresses acting in their struts.A partir de estructuras desplegables planas muy simples, como pueden ser las aspas articuladas en su punto medio, se plantea una serie sucesiva de combinaciones espaciales de complejidad creciente que mantienen las mismas condiciones de plegabilidad que los elementos de partida. Mediante una metodología razonada de ensamblaje, paralela a la utilizada en estructuras espaciales de barras convencionales, se definen distintos tipos de estructuras desplegables en una clasificación que pretende ser completa y que se resume en cuatro tipos básicos. Estos tipos, a su vez, pueden tener un crecimiento longitudinal superficial o espacial, multiplicando el número de posibilidades formales así como el de aplicaciones. Si las aspas iniciales tienen algún tipo

Resultados de ensayos de soldadura a tope y por solape, con electrodo, de barras de aceros estirados en frío

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Calavera Ruiz, José

1969-03-01

Full Text Available The authors report on a series of tests carried out in the welding of reinforced concrete bars. The tested bars were cold drawn, with elastic limits of 4,200 and 5,000 kg/cm2. The tests included butt and overlap welding, involving excentric and axial overlaps, with joint reinforcements. Results of these experiments show that if the indicated method is adopted, including an average standard of workmanship, the weld attains 100 % of the bar strength.Los autores dan cuenta de una serie de ensayos realizados sobre soldadura de barras para hormigón armado. Las barras ensayadas son de acero estirado en frío con límites elásticos de 4.200 y 5.000 kp/cm2. Los ensayos abarcaron la soldadura a tope y la soldadura por solape, con sus variantes de solape excéntrico y solape centrado con cubrejuntas. Los resultados de los ensayos demuestran que siguiendo la técnica indicada, y con una calidad normal de ejecución, la soldadura presenta el 100 % de la resistencia de la barra.

Espécie invasora em unidade de conservação: Achatina fulica (Bowdich, 1822 no Parque Estadual Carlos Botelho, Sete Barras, SP, Brasil (Nota Científica. Invasive species in conservation unit: Achatina fulica (Bowdich, 1822 in Carlos Botelho State Park, Sete Barras, SP, Brazil (Scientific Note.

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Marilda Rapp de ESTON

2006-12-01

Full Text Available O caramujo-gigante-africano, Achatinafulica (Mollusca-Achatinidae, considerado umadas cem piores espécies invasoras do mundo,causando sérios danos ambientais, é registrado pelaprimeira vez para o Parque Estadual CarlosBotelho, município de Sete Barras, Estado de SãoPaulo, Brasil.The Giant African Snail, Achatina fulica(Mollusca-Achatinidae, considered as one of ahundred worst world’s invasive species, causingserious environmental damages, is registered forthe first time for Carlos Botelho State Park, countyof Sete Barras, state of São Paulo, Brazil.

Geochemical pattern of rare-earth elements from ore deposits of Sete Barras and Volta Grande-PR

International Nuclear Information System (INIS)

Ronchi, L.H.; Dardenne, M.A.

1987-01-01

The fluorite ore deposits of Volta Grande and Sete Barras in Parana show similar REE distribution patterns. Fluorite ores from other regions in Parana e Santa Catarina show marked differences in the REE pattern which suggest different modes of origin. (author) [pt

Processamento de barras de cereais com adição de farinha de batata-doce (Ipomoea batatas L.) Processing of cereal bars with added sweet potato flour (Ipomea batatas L.)

OpenAIRE

Bezerra, José Raniere Mazile Vidal; UNICENTRO; Rigo, Maurício; UNICENTRO; Teixeira, Ângela Moraes; UNICENTRO; Angelo, Mariana Alves; UNICENTRO; Czaikoski, Aline; Graduanda em Engenharia de Alimentos, bolsista Fundação Araucária. BIC/Universidade Estadual do Centro Oeste - UNICENTRO.

2015-01-01

Considerando o crescimento do segmento de barras de cereais, a importância da cultura da batata-doce (Ipomoea batatas L.) e seu valor nutricional, este trabalho teve por objetivo a elaboração de barras de cereais com adição de diferentes teores de farinha de batata-doce e sua avaliação de aceitação sensorial, e ainda, a determinação da composição proximal da formulação melhor avaliada sensorialmente. A farinha da batata-doce e as barras de cereais adicionadas a farinha foram submetidas às det...

Variación temporal y espacial de aves playeras en la laguna Barra de Navidad, Jalisco, en tres temporadas no reproductivas Temporal and spatial variation of shorebirds in Barra de Navidad lagoon, Jalisco, during three non-breeding seasons

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Salvador Hernández

2012-09-01

Full Text Available Hay un escaso conocimiento de las aves playeras en los humedales costeros de Jalisco, y en particular en la laguna Barra de Navidad. El presente trabajo contribuye al conocimiento de este grupo de aves y describe su distribución temporal y espacial en la laguna Barra de Navidad durante tres temporadas no reproductivas (1999-2000, 2006-2007 y 2008-2009. Se realizaron censos mensuales de noviembre-abril en las tres temporadas con el fin de registrar todas las especies de aves playeras. Se identificaron 19 especies (tres residentes y 16 visitantes de invierno, de las cuales Charadrius wilsonia, Limosa fedoa y Tringa semipalmata presentaron la mayor abundancia. Doce especies son consideradas como prioritarias en la “Estrategia para la Conservación y Manejo de las Aves Playeras y su Hábitat en México”. El mayor número de especies fue registrado en noviembre, diciembre y marzo en la primera y tercera temporada. El mayor número de individuos fue registrado alimentándose en marea baja, principalmente en diciembre, enero y febrero de la primera y tercera temporada. En marea baja hubo un mayor número de especies e individuos alimentándose en la zona C. Esta zona se caracterizó por tener sustratos lodosos expuestos durante marea baja y que fueron aprovechados por las aves para alimentarse. La laguna Barra de Navidad proporcionó hábitats de alimentación y descanso para las aves residentes y migratorias. Sin embargo, estos hábitats se ven amenazados por las actividades humanas realizadas dentro de la laguna, que sin duda tendrán consecuencias negativas para la distribución y abundancia de las aves playeras.Resident and migratory shorebirds inhabit different kinds of wetlands such as lagoons, rivers and seashores among others. In recent years, these areas have been importantly affected by urban, agriculture and touristic activities, such as the Barra de Navidad lagoon, for which little information is available to support conservation

El tratado de Derecho Administrativo del Profesor Rodolfo Carlos Barra

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Daniel Hugo Martins

2014-06-01

Full Text Available En el "Tratado" cuyos primeros dos tomos han sido públicados recientemente, Barra se propone aplicar la "tesis cuatripartita" al derecho administrativo, con base en la "filosofía perenne" y la interpretación tomista del derecho."Este trabajo -dice- propugna la sistematización y mediatización del Derecho Administrativo, como rama del derecho público que garantiza el cumplimiento del acto justo en las relaciones de justicia distributiva y está referido a la regulación de la relación jurídica Estado (Administración Pública - administrado"

Vespas Sociais (Vespidae: Polistinae em Fitofisionomias Urbanas: um Checklist do Município de Barra Mansa, Rio de Janeiro, Brasil

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Carlos Alberto Souza

2016-12-01

Checklist of Social Wasps (Vespidae: Polistinae in Two Green Urban Areas in the Municipality of Barra Mansa, Rio de Janeiro, Brazil Abstract. New concepts on city planning and urbanization have progressively encouraged the creation and maintenance of public or private green areas, which are important feeding and shelter zones for several species of social wasps. However, in spite of the sampling effort and representativeness of southeastern Brazil, knowledge of richness and abundance of social wasps in Rio de Janeiro is still poor. The present study aimed at inventorying the fauna of social wasps in urban phytophysiognomies in downtown Barra Mansa, state of Rio de Janeiro, within the campus of Barra Mansa University. We sampled two areas for 12 months - a human-modified grassland and a reforested area, through active search with insect nests, Möericke traps, and aromatic traps. We collected 148 wasps of three tribes, four genera, and 17 species. Through active search we recorded 70.7% of the species sampled. The tribe Epiponini showed the highest species richness, and Polybia chrysothorax Lichtenstein and Polybia erythrothoraxla Richards were recorded for the first time in the state of Rio de Janeiro. In the anthropic field it was observed greater diversity (H’ = 1,890, equitability (J = 0,7605, and minor dominance (D(1/D = 0,2124, while in the reforested area was obtained H’ = 1,582, J = 0,6366 e D(1/D = 0,3465. The configuration and size of the reforested area in the campus Barra Mansa (UBM are insufficient elements to restrict the movement of species or segregate communities when considering the anthropic field, thereby still allowing that species could also be sampled between the areas.

Mesozooplankton of the estuarine system of Barra das Jangadas, Pernambuco, Brazil

OpenAIRE

Cavalcanti, Eliane A. H.; Neumann-Leitão, Sigrid; Vieira, Dilma A. do N.

2008-01-01

Estudos sobre o mesozooplâncton foram realizados no sistema estuarino de Barra das Jangadas, Pernambuco, Brasil (8º14'36"S, 34º56'28"W) visando analisar a estrutura da comunidade. As amostras foram obtidas com rede de plâncton, com malha de 300 µm, durante os períodos, seco (janeiro/2001) e chuvoso (julho/2001), nas marés de sizígia e de quadratura, em intervalos de três horas. Foram identificados 37 taxa, destacando-se Copepoda com as espécies Pseudodiaptomus acutus (F. Dahl, 1894), Pseudodi...

Influência da adição de fibras de aço na tensão de aderência de barras de aço retilíneas

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D. L. Araújo

Full Text Available A aderência entre a barra de aço e o concreto permite que haja a compatibilização entre os dois materiais, validando o uso do concreto armado como material de construção. Quanto melhor a aderência, menores são as aberturas das fissuras e mais protegida fica a armadura. Assim, busca-se nessa pesquisa investigar a influência das fibras de aço na aderência aço-concreto. Para tanto, foram ensaiados trinta e três corpos de prova, com dimensões de 200 mm x 300 mm x 150 mm, dos quais foi arrancada uma barra de aço neles concretada. As variáveis analisadas foram o diâmetro da barra (10 mm, 12,5 mm, 16 mm e 20 mm, o comprimento aderente (cinco e dez vezes o diâmetro da barra e o volume de fibras de aço adicionadas ao concreto (1% e 2%. Foram utilizadas fibras de aço com ganchos nas extremidades, comprimento de 35 mm e relação de aspecto igual a 65. Dos ensaios de arrancamento foi determinada a forma e a força de ruptura em cada um dos modelos. Adicionalmente, foram feitas simulações computacionais dos ensaios realizados com barra de 10 mm de diâmetro. Tanto os resultados dos ensaios experimentais quanto da modelagem mostraram que as fibras estudadas exercem pequena influência na tensão de aderência entre a barra e o concreto. Por outro lado, quando a ruptura da aderência se dá pelo fendilhamento do cobrimento de concreto, a influência das fibras é significativa.

Canine visceral leishmaniasis in Barra de Guaratiba, Rio de Janeiro, Brazil: assessment of risk factors

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Cabrera Maria Alice A.

2003-01-01

Full Text Available Barra de Guaratiba is a coastal area of the city of Rio de Janeiro where American visceral leishmaniasis (AVL is endemic. Although control measures including killing of dogs and use of insecticides have been applied at this locality, the canine seroprevalence remains at 25% and during 1995 and 1997 eight autochthonous human cases were notified. In order to evaluate factors related to the increase of the risk for Leishmania (Leishmania chagasi infection in dogs we have screened 365 dogs by anti-Leishmania immunofluorescent antibody test (IFAT and captured sandflies in the domestic and peridomestic environment. Some variables related to the infection were assessed by uni- and multivariate analysis. The distance of the residence from the forest border, its altitude and the presence of the opossum Didelphis marsupialis in the backyard, were found predictor factors for L. (L. chagasi infection in dogs in Barra de Guaratiba. The presence of Lutzomyia longipalpis in the peridomestic environment indicates the possibility of appearence of new human cases. Our data also suggest the presence of a sylvatic enzootic cycle at this locality.

Curicica, de "fim do mundo" a "Barra Olímpica"

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Sampaio, Lilian Amaral de

2014-01-01

Curicica, de "fim do mundo" à "Barra Olímpica" é um estudo sobre os impactos gerados pelas transformações urbanas em processo no entorno do futuro Parque Olímpico, na Baixada de Jacarepaguá, Rio de Janeiro. O trabalho tem como ponto de partida a elaboração de um diagnóstico feito para a região de Curicica por ocasião do Programa Morar Carioca (2012), para urbanização das favelas da área, posteriormente suspenso. Trata-se de uma exploração sobre a lógica que norteia a (re)ocupação de uma área ...

Aceitabilidade e estabilidade físico-química de barras de cereais elaboradas à base de aveia e linhaça dourada

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Rosana Colussi

2013-12-01

Full Text Available Matérias-primas de elevado valor nutricional e com propriedades funcionais devem ser utilizadas no desenvolvimento de produtos benéficos à saúde do consumidor. Neste trabalho, objetivou-se estudar combinações de aveia e linhaça dourada na elaboração de barras de cereais, sendo avaliadas a composição química, a aceitabilidade sensorial e a estabilidade pelo período de 60 dias de armazenamento. As barras de cereais foram elaboradas com o emprego de ingredientes secos e agentes ligantes, nas proporções de 70% e 30%, respectivamente. O delineamento empregado foi o de mistura binária com variações proporcionais nas formulações, sendo realizadas três repetições no ponto central. As barras de cereais foram avaliadas por 35 provadores não treinados quanto à aceitabilidade e à intenção de compra. A estabilidade foi avaliada pela determinação de acidez graxa, índice de peróxidos e atividade de água, e a composição química, pela determinação de umidade, proteínas, cinzas, lipídios, fibra alimentar e carboidratos. Para a composição química, foi realizada a análise de regressão, obtendo-se os coeficientes de determinação e falta de ajuste. Nas demais determinações, os resultados foram analisados pelo emprego da análise da variância (ANOVA e as médias foram comparadas pelo teste de Tukey a 5% de significância. A aveia combinada com linhaça dourada pode ser utilizada na elaboração de barras de cereais por apresentar características sensoriais adequadas e ser fonte de fibras. A formulação de melhor aceitabilidade sensorial foi o ponto central, com emprego de 50% de aveia e 50% de linhaça dourada. As barras de cereais apresentam boa estabilidade devido à baixa atividade de água e à não formação de peróxidos.

O efeito da sugestão de falsa informação para eventos emocionais: quão suscetíveis são nossas memórias? El efecto de información engañosa para eventos emocionales: ¿cuán susceptibles son nuestras memorias? Misinformation effect on memory for emotional events: how susceptible are our memories?

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Carmem Beatriz Neufeld

2008-09-01

Full Text Available O presente trabalho visa fornecer evidências científicas da susceptibilidade das memórias a distorção através do estudo das falsas memórias (lembranças de eventos que, na realidade, não ocorreram para situações emocionalmente carregadas. Foi usada a versão brasileira dos instrumentos e procedimentos de Cahill, Prins, Weber, e McGaugh e adaptada por Neufeld, Brust e Stein para a investigação do efeito da emoção na memória e nas falsas memórias. O experimento investigou o efeito de sugestão de falsa informação em 138 alunos universitários. O procedimento também testou um material de sugestão de falsa informação congruente com a história na forma de um artigo de jornal. Os resultados indicam que a memória verdadeira não foi imune a erros e distorções, apesar de aparentemente ter sido auxiliada pela emocionalidade do evento. Ou seja, a sugestão de falsa informação parece ter auxiliado na discriminação dos itens sugeridos.El presente trabajo tiene el objetivo de proporcionar evidencias científicas de la susceptibilidad de la memoria y su distorsión a través del estudio de las falsas memorias (recuerdo de eventos que en realidad, no ocurrieron para situaciones emocionalmente intensas. En este estudio se utilizó la versión brasileña de los instrumentos y procedimientos Cahill, Prins, Weber y McGaugh adaptada por Neufeld, Brust y Stein para la investigación del efecto de la emoción en la memoria y las falsas memorias. El experimento investigo el efecto de sugestión de falsa información en 138 alumnos universitarios. El procedimiento también evaluó un material de sugestión de falsa información congruente con la historia en forma de un artículo de periódico. Los resultados indican que la memoria verdadera no fue inmune a errores y distorsiones a pesar de aparentemente haber sido auxiliada para la emocionalidad del evento, o sea, la sugestión de la falsa información parece haber auxiliado la

O conhecimento ictiológico tradicional dos pescadores da cidade de Barra, região do médio São Francisco, Estado da Bahia, Brasil The traditional ichthyological knowledge of fishermen from the city of Barra, median region of San Francisco, state of Bahia, Brazil

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Márcia Nogueira de Melo

2002-05-01

Full Text Available No artigo discute-se o conhecimento ictiológico tradicional de uma comunidade pesqueira da cidade de Barra, localizada na região oeste do Estado da Bahia, nordeste do Brasil. Os pescadores de Barra desenvolvem suas atividades habituais às margens dos rios São Francisco e Grande. O trabalho de campo foi realizado no período de janeiro a junho de 2000. Foram consultados 15 informantes (10 homens e 5 mulheres através de entrevistas livres e semi-estruturadas com o objetivo de registrar os aspectos cognitivos (etnotaxonomia, reprodução, comportamento, ecologia trófica, hábitat e culturais (restrições ao consumo de peixes e usos na medicina popular relacionados com as espécies de peixes locais. Dezoito espécies foram coletadas, identificadas e encontram-se depositadas no Laboratório de Ictiologia da Universidade Estadual de Feira de Santana. Os resultados revelam que os pescadores ainda possuem conhecimentos teóricos e práticos importantes que devem ser considerados em estudos de manejo, conservação e uso sustentável dos recursos pesqueiros. Problemas ecológicos de origem antrópica, tais como pesca predatória e introdução de espécies exóticas, vêm afetando o modo de vida dos pescadores tradicionais, tanto os da cidade de Barra como os das áreas adjacentes.This paper deals with the traditional ichthyological knowledge of fishermen’s community from the city of Barra, which is located in the west region of Bahia State, Northeast Brazil. These fishermen develop their usual activities at the edges of São Francisco and Grande rivers. Fieldwork was carried out from January to June 2000. A total of 15 informants (ten male and five female were consulted through open and semi-structured interviews, with the aim to record both the cognitive (ethnotaxonomy, reproduction, behaviour, food ecology, habitat and cultural aspects (restrictions to the fish eating and their use as folk medicine towards the local fish species. Eighteen

Landscape changes in a coastal system undergoing tourism development: implications for Barra de Navidad Lagoon, Jalisco, Mexico

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Tara L. Holland

2012-02-01

Full Text Available In this study, changes in land cover and land use patterns that occurred between 1985 and 2000 in the surrounding basin of the Barra de Navidad coastal lagoon in Jalisco, Mexico are quantified and explained. Two satellite images from 1985 (Landsat TM and 2000 (Landsat ETM+ were analyzed with supervised classification and ground truthing to evaluate changes in six land use/cover categories: lagoon, agriculture, urban/tourist, tropical dry forest, mangrove and bare substratum. Changes in land use composition were evaluated using a transition matrix and changes to configuration were interpreted using landscape metrics. Results show that urban and tourist areas expanded between 1985 and 2000, mostly at the expense of forested and bare land. Mangroves showed a large relative decrease in area (-39% and experienced fragmentation. These changes appear to be related to increased sedimentation a fan progradation into Barra de Navidad lagoon. These results may serve as a model for comparison in other systems experiencing multiple stressors, especially changes related to tourism and the intensification of resource extraction.

Relació entre la falsa creença de segon ordre i la memòria de treball: recerca bibliogràfica

OpenAIRE

Ramírez Berengué, Ramon

2014-01-01

Aquest treball de recerca bibliogràfica fa un recull de totes les publicacions realitzades entre els anys 2000 i el 2013. L'objectiu és el de recavar tota la informació possible que relacionin la memòria de treball i la falsa creença de segon ordre. El treball recull una explicació dels conceptes i la seva posició actual en la literatura científica, més tard realitza un anàlisis cronològic dels articles per extreure unes conclusions d'aquests i fer un recull cap a on apunten les publicacions ...

UTILIZACIÓN DEL ACRÍLICO DENTAL (metil metacrilato) COMO BARRA ESTABILIZADORA-CONECTORA PARA REDUCCIONES CERRADAS EN FRACTURAS DE TIBIA/PERONÉ O RADIO/CÚBITO EN CANINOS

OpenAIRE

Cavero A., Francisco; Fernández A., Víctor

2012-01-01

El metil metacrilato (mmc) es una resina acrílica utilizada en moldes para fabricar prótesis dentales y puede cumplir la función de barra estabilizadora-conectora en la reducción de fracturas, permitiendo la colocación de clavos en planos múltiples. El presente trabajo tuvo como objetivo comprobar que el acrílico dental sirve como barra conectora en la fijación externa esquelética, y demostrar que es posible fijar las fracturas con un método poco traumático, alejado del foco fracturario, para...

Código de barras del ADN y sus posibles aplicaciones en el campo de la Entomología

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Analía A. LANTERI

2007-01-01

Full Text Available En este artículo se abordan algunos aspectos de la controversia sobre la iniciativa «Código de barras del ADN», y se hace hincapié en sus potenciales aplicaciones en Entomología. Esta iniciativa propone emplear información dentro de una misma región génica (gen mitocondrial de la Citocromo c Oxidasa I = COI, en todas las especies vivientes y con condiciones de secuenciación universalmente aceptadas y estandarizadas. En la actualidad, no pretende sustituir la taxonomía alfa y la filogenia sino agilizar las tareas de identificación, especialmente en el campo de la Biomedicina (identificación de patógenos, parásitos y vectores, el control de plagas (intercepción de especies invasoras, cualquiera sea su estado de desarrollo ontogenético y los estudios sobre conservación de la biodiversidad. Para arribar a una correcta delimitación de las especies biológicas es preciso contar con las secuencias de COI de numerosos individuos a lo largo de todo su rango geográfico y además, secuencias de genes nucleares e información morfológica y biológica detallada. Las «Unidades Evolutivas Significativas», identificadas sobre la base del «código de barras», podrían corresponder tanto a morfoespecies como a especies crípticas y a subespecies o linajes con diferentes preferencias de huéspedes. La integración del «código de barras del ADN», el trabajo de campo, las colecciones de museos y la investigación científica resultan imprescindibles para que esta herramienta redunde en avances significativos en el campo de la Sistemática Entomológica.

La fatiga en las barras de acero corrugado para refuerzo de hormigón

OpenAIRE

Avila Kildal, Francisco

2003-01-01

Para conseguir aprovechar los recursos que la sociedad invierte en infraestructuras de manera óptima es imprescindible, para la ingeniería civil, un buen conocimiento de los materiales y de sus propiedades. Partiendo de esta premisa, el objetivo de esta tesina es aportar conocimiento a la caracterización de las barras de acero corrugado para refuerzo de hormigón en su funcionamiento frente a la fatiga. Definimos fatiga como la alteración mecánica de los materiales bajo el ef...

Productive organization of ocean artisan fishing in Sao Joao da Barra, RJ

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Alcimar das Chagas Ribeiro

2012-05-01

Full Text Available This paper discusses the economic relations found in artisan fishing in the municipality of São João da Barra, RJ, based on the conceptual structure of supply chains, in order to understand the levels of interaction among the different actors, and how this reflects in their competitiveness. The qualitative and exploratory survey was carried by using the action research methodology aiming at the identification of the real problems that weakens the activity and, more specifically, possible regulation alternatives. Such effort is justified by the historical and economic importance of such activity which, in recent years, has suffered a severe depression.

Insect galls of Restinga de Marambaia (Barra de Guaratiba, Rio de Janeiro, RJ).

Science.gov (United States)

Maia, V C; Silva, L O

2016-04-19

Thirty-one morphotypes of insect galls and two flower damages were found on 16 families, 22 genera and 24 plant species in Restinga de Marambaia (Barra de Guaratiba, Rio de Janeiro, RJ). Fabaceae and Myrtaceae were the plant families with the greatest richness of insect galls (4 and 6 morphotypes, respectively), and the greatest number of galled plants (four and three species, respectively). Galls were mostly found on leaves and stems (77% and 10%, respectively). The galling insects are represented by Diptera, Lepidoptera, and Hemiptera. The majority of the galls (81%) were induced by gall midges (Cecidomyiidae: Diptera).

Application of roasted rice bran in cereal bars Aplicação de farelo de arroz torrado em barras de cereais

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Marina Costa Garcia

2012-12-01

Full Text Available The objective of this study was to evaluate the viability of using microwave-roasted rice bran as an ingredient in high-fiber cereal bars to obtain a product with good acceptability. The influence of the rice flakes, corn flakes, and roasted rice bran levels on the physical and chemical characteristics of the cereal bars was studied. The overall acceptability of three selected formulations was also evaluated. An increase in the roasted rice bran level in the formulation reduced the force of rupture and water activity, resulted in intermediate density, and caused darkening of the bars. The contents of lipid and total dietary fiber were higher in the formulation with the highest rice bran content, which was therefore classified as functional food. The formulation containing 0.34; 0.32; and 0.34 roasted rice bran, rice flakes, and corn flakes, respectively, seemed to be the best outcome. Cereal bars with roasted rice bran levels between 10 and 20% were accepted by consumers.O objetivo do trabalho foi avaliar a viabilidade da utilização do farelo de arroz torrado, em microondas, como ingrediente de barras de cereais ricas em fibras, para obtenção de um produto com boa aceitabilidade. A influência dos teores de flocos de arroz, flocos de milho e farelo de arroz torrado nas características físicas, químicas de barras de cereais foram estudados. A aceitabilidade global de três formulações selecionadas também foi avaliada. O aumento no teor de farelo de arroz torrado nas formulações reduziu a força de ruptura e atividade de água, a densidade foi intermediária e houve escurecimento das barras. O conteúdo de lipídeos e fibra alimentar total foram maiores nas formulações com maior teor de farelo de arroz, portanto, classificada como alimento funcional. A formulação com a proporção de 0,34/0,32/0,34 de farelo de arroz torrado/flocos de arroz/flocos de milho, se apresentou mais próxima do desejável. Barras de cereais formuladas com

Preliminary characterization of the rare earth ore from the Barra do Itapirapua, Sao Paulo and Parana states, Brazil. Detail 1 area; Caracterizacao preliminar do minerio de terras raras da Barra do Itapirapua, SP/PR - area de detalhe 1

Energy Technology Data Exchange (ETDEWEB)

Lorenzi, M.L.B.; Lorenzi, V.E.; Kahn, H

1996-12-31

The main rare earth mineralization on Barra do Itapirapua Alkaline-Carbonatitic Complex is related to the weathering mantle of the Serrana Body carbonatite plug - detail 1 area. The present work describes the preliminary RE ore types established from correlation between geological observations, geochemical weathering profile and mineralogical studies. Mineralogical studies, comprising around 40 thin section analysis, were performed by scanning electron microscopy (SEM) with energy dispersive systems (EDS). (author) 5 refs., 2 figs., 1 tab.

SETTLEMENT ANALYSIS OF AN EMBANKMENT ON VERY SOFT SOIL IN BARRA DA TIJUCA

OpenAIRE

CHRISTIANO FARIA TEIXEIRA

2012-01-01

um depósito de solos muito moles da Barra da Tijuca (Baixada de Jacarepaguá), que pertence a uma planície costeira do Rio de Janeiro (RJ). O perfil de solos muito moles de fundação possuía até 17 m de espessura, caracterizados pelo Nspt igual a 0. O aterro foi construído em etapas e os recalques foram acelerados com a instalação de drenos verticais pré-fabricados na fundação. A construção do aterro durou cerca de 1,5 ano e foi monitorada por meio de instrumentação geotécnic...

Utilización del acrílico dental (metil metacrilato) como barra estabilizadora-conectora para reducciones cerradas en fracturas de tibia/peroné o radio/cúbito en caninos

OpenAIRE

Cavero A., Francisco; Fernández A., Víctor

2005-01-01

El metil metacrilato (mmc) es una resina acrílica utilizada en moldes para fabricar prótesis dentales y puede cumplir la función de barra estabilizadora-conectora en la reducción de fracturas, permitiendo la colocación de clavos en planos múltiples. El presente trabajo tuvo como objetivo comprobar que el acrílico dental sirve como barra conectora en la fijación externa esquelética, y demostrar que es posible fijar las fracturas con un método poco traumático, alejado del foco fracturario, para...

Variación temporal y espacial de aves playeras en la laguna Barra de Navidad, Jalisco, en tres temporadas no reproductivas

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Salvador Hernández

2012-09-01

Full Text Available Hay un escaso conocimiento de las aves playeras en los humedales costeros de Jalisco, y en particular en la laguna Barra de Navidad. El presente trabajo contribuye al conocimiento de este grupo de aves y describe su distribución temporal y espacial en la laguna Barra de Navidad durante tres temporadas no reproductivas (1999-2000, 2006-2007 y 2008-2009. Se realizaron censos mensuales de noviembre-abril en las tres temporadas con el fin de registrar todas las especies de aves playeras. Se identificaron 19 especies (tres residentes y 16 visitantes de invierno, de las cuales Charadrius wilsonia, Limosa fedoa y Tringa semipalmata presentaron la mayor abundancia. Doce especies son consideradas como prioritarias en la “Estrategia para la Conservación y Manejo de las Aves Playeras y su Hábitat en México”. El mayor número de especies fue registrado en noviembre, diciembre y marzo en la primera y tercera temporada. El mayor número de individuos fue registrado alimentándose en marea baja, principalmente en diciembre, enero y febrero de la primera y tercera temporada. En marea baja hubo un mayor número de especies e individuos alimentándose en la zona C. Esta zona se caracterizó por tener sustratos lodosos expuestos durante marea baja y que fueron aprovechados por las aves para alimentarse. La laguna Barra de Navidad proporcionó hábitats de alimentación y descanso para las aves residentes y migratorias. Sin embargo, estos hábitats se ven amenazados por las actividades humanas realizadas dentro de la laguna, que sin duda tendrán consecuencias negativas para la distribución y abundancia de las aves playeras.

Modeling pollution potential input from the drainage basin into Barra Bonita reservoir, São Paulo – Brazil

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RB. Prado

Full Text Available In this study multi-criteria modeling tools are applied to map the spatial distribution of drainage basin potential to pollute Barra Bonita Reservoir, São Paulo State, Brasil. Barra Bonita Reservoir Basin had undergone intense land use/land cover changes in the last decades, including the fast conversion from pasture into sugarcane. In this respect, this study answers to the lack of information about the variables (criteria which affect the pollution potential of the drainage basin by building a Geographic Information System which provides their spatial distribution at sub-basin level. The GIS was fed by several data (geomorphology, pedology, geology, drainage network and rainfall provided by public agencies. Landsat satellite images provided land use/land cover map for 2002. Ratings and weights of each criterion defined by specialists supported the modeling process. The results showed a wide variability in the pollution potential of different sub-basins according to the application of different criterion. If only land use is analyzed, for instance, less than 50% of the basin is classified as highly threatening to water quality and include sub basins located near the reservoir, indicating the importance of protection areas at the margins. Despite the subjectivity involved in the weighing processes, the multi-criteria analysis model allowed the simulation of scenarios which support rational land use polices at sub-basin level regarding the protection of water resources.

Desenvolvimento de barras de cereais à base de aveia com alto teor de fibra alimentar Development of oat based cereal bars with high dietary fiber content

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Luiz Carlos Gutkoski

2007-06-01

Full Text Available A barra de cereal é um alimento nutritivo de sabor adocicado e agradável, fonte de vitaminas, sais minerais, fibras, proteínas e carboidratos complexos. O trabalho objetivou estudar o efeito da concentração de fibra alimentar e de açúcar na calda em barras de cereais elaboradas à base de aveia com alto teor de fibra alimentar. No estudo foram utilizados flocos, farelo e farinha de aveia, do cultivar UPFA 22, selecionado com base no teor de fibras e beta-glucanas. Os ingredientes secos e ligantes foram adquiridos no comércio local e utilizados na proporção de 70 e 30%, respectivamente, em quantidades definidas a partir de testes laboratoriais. O experimento foi realizado em delineamento composto central rotacional aplicável à metodologia de superfície de resposta, sendo avaliado o efeito da concentração de açúcar na calda (70, 75 e 80 °Brix e do teor de fibra alimentar da formulação (12, 16 e 20% na composição química, valor calórico, atividade de água, microbiologia e características sensoriais das barras de cereais. Os resultados das variáveis respostas foram tratados por análise de regressão múltipla. E foram utilizados no modelo matemático de segunda ordem os termos lineares, quadráticos e de interação, significativos. A aveia pode ser utilizada como ingrediente na elaboração de barras de cereais por apresentar textura, sabor e aparência adequados. O uso de aveia na formulação possibilita produzir barras de cereais com alto teor de fibra alimentar e fonte de beta-glucanas. As barras de cereais apresentam propriedades sensoriais agradáveis, similares às industrializadas e melhor aceitas quando elaboradas com média concentração de açúcar na calda e altos teores de fibra alimentar. As barras de cereais apresentam baixa atividade de água e atendem às especificações sanitárias, sendo estáveis durante 60 dias de armazenamento.Cereal bars are a nutritional food of sweetened and acceptable flavor

Flujo de carga con armónicos empleando la matriz impedancia de barras

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José A González Quintero

2011-03-01

Full Text Available Se describe un flujo de armónicos empleando la matriz impedancia de barras. El algoritmo propuesto permite hallar losvoltajes de cada nodo del circuito sin tener que realizar la solución simultánea de todas las ecuaciones no linealescorrespondientes a cada nodo, ni siquiera la solución simultánea de las ecuaciones correspondientes a una redreducida de nodos no lineales solamente.  This work describes a harmonic load flow using the bar impedance matrix. The proposed algorithm permit to findevery node voltage of the circuit without to realize the simultaneous solution of all the non-linear equationscorresponding to each node, not even the simultaneous solution of the equations corresponding to a reducednetwork of only non-linear nodes.

Atribuição de falsas crenças no desenvolvimento de linguagem de crianças com síndrome de Down Attribution of false beliefs in the language development of children with Down syndrome

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Tatiana Pires da Silva

2010-01-01

Full Text Available OBJETIVO: Avaliar atribuição de falsa crença em indivíduos com Síndrome de Down. MÉTODOS: Onze crianças usuárias de comunicação verbal, com síndrome de Down, retardo mental de grau leve a grave, de ambos os sexos, na faixa etária entre quatro e oito anos e atendidas em instituição compuseram o Grupo Down (GD. Além disso, 85 crianças sem alterações do desenvolvimento, na faixa etária entre quatro e seis anos, matriculadas em EMEI, constituíram o Grupo Controle (GC. Foram utilizados o Teste de Vocabulário por Imagem Peabody (TVIP para a comparação do nível de compreensão verbal dos grupos, e o "teste dos smarties" adaptado, para avaliar a atribuição de falsa crença. RESULTADOS: Na análise do TVIP verificou-se diferença estatisticamente significante entre os grupos, sendo que o GD apresentou pontuação abaixo do terceiro desvio-padrão e, as crianças do GC, abaixo do primeiro desvio-padrão. Em relação à análise da atribuição de falsa crença, o GC apresentou progressão de acertos em todas as questões conforme o aumento da faixa etária. O mesmo não foi observado para o GD, sendo que os melhores resultados foram os dos indivíduos com maior tempo de terapia fonoaudiológica na instituição. Não houve correlação entre o nível de vocabulário receptivo e a habilidade de falsa crença. CONCLUSÃO: Em todas as questões houve melhor desempenho do GC em comparação ao GD. Sendo assim, foi possível analisar a falsa crença em crianças com síndrome de Down.PURPOSE: To evaluate the attribution of false belief in individuals with Down syndrome. METHODS: Eleven children of both genders with Down syndrome and ages between four and eight years composed the Down Group (DG. All subjects used verbal communication, had mild to severe mental retardation, and were attended at the same institution. In addition, 85 children within normal development with ages between four and six years were recruited at an elementary

Avaliação sorológica para detecção de anticorpos anti-Leishmania em cães e gatos no bairro de Santa Rita de Cássia, Município de Barra Mansa, Estado do Rio de Janeiro Serological evaluation for detection of anti-Leishmania antibodies in dogs and cats in the district of Santa Rita de Cássia, municipality of Barra Mansa, State of Rio de Janeiro

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Fabiano Borges Figueiredo

2009-04-01

Full Text Available A partir de um caso canino de leishmaniose tegumentar americana na localidade de Santa Rita de Cássia, município de Barra Mansa, Rio de Janeiro, foi realizado um inquérito sorológico em 177 cães e 43 gatos. Na avaliação das amostras de soros caninos, 10% foram positivos na reação de imunofluorescência indireta e 10,7% no ensaio imunoenzimático. Entre as amostras de soros felinos testados, nenhum animal foi positivo na reação de imunofluorescência indireta e apenas um (2,4% felino apresentou reação positiva ao ensaio imunoenzimático. A detecção de Leishmania braziliensis, autóctone em Barra Mansa, faz um alerta para a instalação de um possível foco de leishmaniose tegumentar americana nessa região.From a canine case of american cutaneous leishmaniasis in the locality of Santa Rita de Cássia, municipality of Barra Mansa, Rio de Janeiro, a serological survey was performed on 177 dogs and 43 cats. Evaluation of the canine serum samples showed that 10% had a positive reaction in the indirect immunofluorescence test and 10.7% in the enzyme-linked immunosorbent assay. Among the feline serum samples tested, none of the animals had a positive reaction in the indirect immunofluorescence test and only one (2.4% showed a positive reaction in the enzyme-linked immunosorbent assay. The detection of an autochthonous case of Leishmania braziliensis in Barra Mansa gives warning that a focus of american cutaneous leishmaniasis is possibly becoming established in this region.

Tourism and environmental sustainability in the community of Barra Grande, Cajueiro da Praia, Piauí (PI

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Anderson Fontenele Vieira

2015-12-01

Full Text Available The community of Barra Grande, tourist destination located in Cajueiro da Praia, Piauí (PI, was the object of investigation of this study. Tourism, in this region, increased creating structural, social and environmental change. The aim of the research was to analyze the environmental impacts of tourism in Barra Grande considering the Environmental Sustainability Indicators of BIGS (Brazilian Institute of Geography and Statistics. It was conducted a bibliographic and documentary survey about public politics for tourism and environment, besides the application of semi-structured interviews with eighteen hotels diagnosing three indicators: water supply, sewage disposal, and collection and disposal of solid waste which measure pressure parameters (impacts to the natural environment, qualified the state of that environment and the existence of response mechanisms to minimize the impacts. The scientific relevance consists in the analysis of sustainability through indicators based on Model PER (Pressure-State-Response, adopted by OECD (Organization for Economic Cooperation and Development, in order to conduct strategic actions to solve environmental problems. Regarding the preliminary results, it realizes that the policies have part of their normalizations not carried out in practice. Concerning the field collection in the hotels it was identified that they agree with two of evaluated qualitative parameters, proving that the destination needs to improve as sustainability. Finally, it is expected that data may contribute to tourism planning, as well as building elements to support discussions, new research approaches on the viability and adherence of sustainable tourism segments in Piauí context or in other regions of Brazil.

Fenologia de Lafoensia pacari A.St.-Hil. (Lythraceae em Barra do Garças, Mato Grosso, Brasil Phenology of Lafoensia pacari A.St.-Hil. (Lythraceae in Barra do Garças, Mato Grosso State, Brazil

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L.W. Santos

2009-01-01

Full Text Available Lafoensia pacari A.St.-Hil. é uma espécie da flora do cerrado usada na medicina popular como anti-úlcera, antifúngica, antibactericida, anti-inflamatória, febrífuga, para emagrecimento e no tratamento de pneumonia, dores de estômago e coceiras. Estudou-se a fenologia de L. pacari no cerrado do Parque Estadual da "Serra Azul", região de Barra do Garças-MT (15º 51' 58" S e 52º 15' 37" W, à 645 m de altitude, durante o período de 24 meses. Verificou-se que as fenofases são sazonais, com floração nos meses de abril a agosto, frutificação de junho a setembro, brotação no início da estação chuvosa de outubro a dezembro e queda de folhas de julho a setembro, no final da estação seca.Lafoensia pacari is a species from the Brazilian cerrado used in folk medicine to control ulcers, fungal and bacterial diseases, inflammations, fevers, pneumonia, stomachaches, and itching, as well as to lose weight. L. pacari phenology was studied for 24 months in the cerrado at "Serra Azul" State Park, in the region of Barra do Garças, Mato Grosso State, Brazil (15º 51' 58" S and 52º 15' 37" W, at 645 m altitude. Phenophases are seasonal, with flowering from April to August, fruiting from June to September, sprouting from October to December, during the beginning of the rainy season, and leaf fall from July to September, at the end of the dry season.

Estabilidade de micro-organismos potencialmente probióticos em barra de cereais - efeito da técnica de incorporação

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Gustavo Almeida Bastos

2015-10-01

Full Text Available Este trabalho objetivou desenvolver formulações de barras de cereais contendo Lactobacillus acidophilus e Saccharomyces boulardii e avaliar a estabilidade destes micro-organismos potencialmente probióticos no produto elaborado durante o tempo de armazenamento (shelf life. Foram formuladas barras de cereais contendo separadamente os agentes probióticos S. boulardii e L. acidophilus, ambos nas formas liofilizada, granulados com lactose e encapsulados em alginato de cálcio. Foi avaliada a estabilidade dos micro-organismos durante o tempo de armazenamento. Tanto a levedura S. boulardii quanto a bactéria L. acidophilus apresentaram maior sobrevida na forma liofilizada, quando comparado com as outras formas de incorporação, mantendo contagem na faixa de 7 log UFC/g, durante oito semanas e na faixa de 7 log UFC/g, durante seis semanas, respectivamente. Comparando os resultados da incorporação dos dois micro-organismos na forma livre liofilizada observouse que a população de S. boulardii apresentou melhores resultados de viabilidade quando comparada com a população de L. acidophilus. Este estudo mostrou que é possível incorporar micro-organismos potencialmente probióticos em barras de cereais, preferencialmente na forma liofilizada, por proporcionar maior sobrevida dos micro-organismos.Palavras-chave: Barra de cereais. Probiótico. Saccharomyces boulardii. Lactobacillus acidophilus. ABSTRACT This study aims to develop formulations of cereal bars that contain Lactobacillus acidophilus and Saccharomyces boulardii and evaluate the stability of these potentially probiotic microorganisms in the elaborated product during the time of storage (shelf life. Cereal bars were designed containing separately the probiotic agents S. boulardii and L. acidophilus, both in the lyophilized form, granulated with lactose form and encapsulated in calcium alginate form. The stability of microorganisms during storage time was evaluated. Both, the yeast S

EL VÉRTIGO DE LAS IDENTIDADES: SECRETOS Y PERSONALIDADES FALSAS EN EL CINE DE HITCHCOCK

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Pablo Francescutti

2016-01-01

Full Text Available En las películas de Alfred Hitchcock, secreto e identidad personal se entrelazan de manera eminente. En sus elencos abundan personajes acusados de delitos que no cometieron, individuos con un pasado oculto, sujetos confundidos con otros, chantajistas que buscan lucrarse con secretos ajenos, agentes dobles, impostores y personalidades escindidas. En sus tramas nadie es lo que parece, todos esconden algo. La identidad es la suma de las máscaras, tal es su mensaje central: también somos lo que ocultamos. Aplicando el corpus teórico desarrollado por Georg Simmel, Erving Goffman, Umberto Eco y otros autores, en este artículo se intenta demostrar desde una perspectiva novedosa que la filmografía del director británico es una concienzuda puesta en escena de las interacciones creadas por la retención deliberada de información, tanto en lo público (secretos oficiales como en lo privado (secretos personales y familiares. Tales interacciones, revela el análisis, se hallan atravesadas por un hilo rojo: la naturaleza maleable de las identidades. Al escenificar sus ambigüedades y paradojas, estos filmes rinden un valioso servicio a la mirada sociológica interesada en fenómenos en proceso de definición, como identidades falsas, robo de identidades y relaciones entre identidades online y offline.

Preliminary characterization of the rare earth ore from the Barra do Itapirapua, Sao Paulo and Parana states, Brazil. Detail 1 area

International Nuclear Information System (INIS)

Lorenzi, M.L.B.; Lorenzi, V.E.; Kahn, H.

1996-01-01

The main rare earth mineralization on Barra do Itapirapua Alkaline-Carbonatitic Complex is related to the weathering mantle of the Serrana Body carbonatite plug - detail 1 area. The present work describes the preliminary RE ore types established from correlation between geological observations, geochemical weathering profile and mineralogical studies. Mineralogical studies, comprising around 40 thin section analysis, were performed by scanning electron microscopy (SEM) with energy dispersive systems (EDS). (author)

Horta orgânica de ervas medicinais: inclusão social na comunidade da Barra em Muriaé/MG - Brasil

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José Luiz de Freitas Paixão

2013-09-01

Full Text Available Foi implantada uma horta orgânica de ervas medicinais na comunidade da Barra (Muriaé, MG com o objetivo de inclusão social de pessoas carentes ao permitir acesso ao tratamento por fitoterapia. O início das atividades foi em janeiro de 2006, com a escolha das espécies, obtenção de mudas e instalação da horta. As 40 espécies selecionadas, sob manejo agroecológico, eram indicadas com terapêutica aos 25 principais problemas de saúde levantados na comunidade. O formato didático da horta, representando o corpo humano, serviu como referência às indicações de uso de cada espécie. A horta foi mantida até meados de 2012 na Barra e transferida ao IFMURIAÉ, em área de cultivo agroecológico, no Bairro Sofoco, onde se realizam as práticas do curso de técnico em agroecologia. A comunidade da Barra auxiliou desde as primeiras ações, sendo atuante na colheita das plantas medicinais. As plantas coletadas foram levadas a sala anexa à Paróquia local onde se realizou o processamento pós-colheita e o preparo de fitoterápicos. A dispensação dos preparados foi em outra sala cedida pela Paróquia. As formas fitoterápicas disponibilizadas à população foram de uso interno (erva seca, tintura, xarope e externo (creme, gel, pomada, sendo as mais procuradas: gel, tintura e xarope. De 2006 a 2012 foram  32.400 atendimentos, média de 385 pessoas/mês. O sucesso do projeto se reflete no aumento do número de espécies utilizadas, passando de 40 espécies em 2006 para 170 espécies em 2012, dentre elas: alecrim de jardim (Rosmarinus officinalis, alfavaca (Ocimum basilicum, amora (Morus alba, arnica brasileira (Solidago microglossa, calêndula (Calendula officinalis, camomila (Matricaria chamomilla, capim gordura (Melinis minutiflora, cavalinha (Equisetum arvense, chapéu-de-couro (Echinodorus grandiflorus e espinheira santa (Maytenus aquifolium.

Influencia del diámetro de la barra y del recubrimiento en las características adherentes del hormigón armado

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Molina, M.

2004-04-01

Full Text Available The bond mechanism on reinforced concrete structures is analysing in this paper. A state of art review of bond phenomenon and characterisation tests, pull-out and beam tests are included. Experimental modifications of RILEM/CEB/FIP pull-out tests on prismatic specimens with different concrete cover are also studied. The objective of eccentric tests is to estimate the maximum bond stress and the loss of concrete cover influence on the reinforced concrete behaviour. Bars diameter and concrete cover influence on concrete-steel stress transfer and different types of failures are analysed finally.

En este artículo se estudia el fenómeno de la adherencia en estructuras de hormigón armado. En primer lugar se incluye una revisión del estado del conocimiento sobre la adherencia y sobre los distintos ensayos de caracterización, principalmente tipo pull-out (ensayos de tracción sobre probetas prismáticas con diferentes longitudes de anclaje según el diámetro de la barra y ensayos Beam Test sobre vigas de hormigón armado. En segundo lugar se presentan los resultados de los ensayos tipo pull-out realizados en la nave de ensayos del Instituto de Ciencias de la Construcción Eduardo Torroja, en probetas prismáticas variando el diámetro y el recubrimiento de las barras según el ensayo normalizado por la RILEM/CEB/FIP con algunas modificaciones. Se realizan ensayos tanto con la barra en posición centrada como con diferentes recubrimientos. El objeto de los ensayos con excentricidad es estimar la influencia del escaso o nulo recubrimiento en el comportamiento del hormigón armado. Finalmente se analizan los diferentes tipos de fallo obtenidos en los ensayos y la influencia del diámetro de la armadura y el recubrimiento en la transferencia de tensiones hormigón acero.

Mesozooplâncton do sistema estuarino de Barra das Jangadas, Pernambuco, Brasil Mesozooplankton of the estuarine system of Barra das Jangadas, Pernambuco, Brazil

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Eliane A. H. Cavalcanti

2008-09-01

Full Text Available Estudos sobre o mesozooplâncton foram realizados no sistema estuarino de Barra das Jangadas, Pernambuco, Brasil (8º14'36"S, 34º56'28"W visando analisar a estrutura da comunidade. As amostras foram obtidas com rede de plâncton, com malha de 300 µm, durante os períodos, seco (janeiro/2001 e chuvoso (julho/2001, nas marés de sizígia e de quadratura, em intervalos de três horas. Foram identificados 37 taxa, destacando-se Copepoda com as espécies Pseudodiaptomus acutus (F. Dahl, 1894, Pseudodiaptomus richardi (F. Dahl, 1894, Acartia lilljeborgi (Giesbrecht, 1892, Parvocalanus crassirostris (Dahl, 1894, Oithona hebes (Santos, 1973 e Notodiaptomus cearensis Wright, 1936. A densidade total durante o período seco variou de 69,34 a 8.568,34 org.m-3. Para o período chuvoso variou de 261,98 a 10.224,83 org.m-3. Os Crustacea meroplanctônicos (Brachyura zoea foram muito freqüentes e muito abundantes, destacando seu importante papel na cadeia trófica pelágica. A diversidade específica durante o período seco, variou de 0,44 a 3,13 bits.ind-1, e para o período chuvoso de 0,66 a 2,93 bits.ind-1. Os baixos valores de diversidade ocorreram devido à dominância de Brachyura (zoea. A análise de agrupamento revelou a formação de dois grupos. O primeiro formado por espécies marinhas e euri-halinas, e o segundo por espécies indicadoras de ambientes estuarinos.Mesozooplankton studies were carried out at the Barra das Jangadas estuarine system, Pernambuco, Brazil (8º14'36"S, 34º56'28"W, to assess its community structure. Samples were collected with a plankton net (300 µm mesh size during the dry (January, 2001 and rainy (July, 2001 seasons, with three hour intervals between each sampling, both in spring and neap tides. Thirty seven mesozooplankton taxa were identified, from which Copepoda were particularly abundant, including the species Pseudodiaptomus acutus (F. Dahl, 1894, Peudodiaptomus richardi (F. Dahl, 1894, Acartia lilljeborgi

Two new species of gall midges (Diptera, Cecidomyiidae) associated with Erythroxylum ovalifolium Peyr. (Erythroxylaceae) from the Barra de Maricá restinga, Maricá, Rio de Janeiro, Brazil.

Science.gov (United States)

Maia, V C; Fernandes, S P C

2011-05-01

Two new species of gall midges (Diptera, Cecidomyiidae) Dasineura ovalifoliae and Clinodiplosis maricaensis are described based on material from the Barra de Maricá restinga, Maricá, Rio de Janeiro, Brazil. Both species are associated with Erythroxylum ovalifolium Peyr. (Erythroxylaceae). The former is the gall inducer and the latter an inquiline.

Two new species of gall midges (Diptera, Cecidomyiidae associated with Erythroxylum ovalifolium Peyr. (Erythroxylaceae from the Barra de Maricá restinga, Maricá, Rio de Janeiro, Brazil

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VC Maia

Full Text Available Two new species of gall midges (Diptera, Cecidomyiidae Dasineura ovalifoliae and Clinodiplosis maricaensis are described based on material from the Barra de Maricá restinga, Maricá, Rio de Janeiro, Brazil. Both species are associated with Erythroxylum ovalifolium Peyr. (Erythroxylaceae. The former is the gall inducer and the latter an inquiline.

Elaboración de barras energéticas para escolares a partir de subproductos industriales de soya y maíz

OpenAIRE

De La Paz Castro, Viviana; Coello Ojeda, Karín Elizabeth

2013-01-01

El Programa de Alimentación Escolar del Ecuador (PAE) ofrece a escuelas fiscales productos como complemento alimenticio que contienen un adecuado aporte de calorías, proteínas, vitaminas y minerales con el propósito de mejorar la nutrición y por consiguiente la capacidad en el aprendizaje de los niños en edad escolar. Entre los productos que el PAE distribuye se encuentra la granola en barra hecha a base de avena, la cual al ser una materia prima importada eleva el costo del producto final. ...

Produção e avaliação da qualidade das barras de cereais elaborada com farinha de facheiro

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J. N. V. Deodato

2015-10-01

Full Text Available As cactáceas constituem um importante elemento da paisagem, apresentando caules suculentos, cobertos por espinhos de diversas formas, tamanhos e dimensões, junto a outras espécies de cactáceas, formam a paisagem típica da região semiárida do Brasil. O facheiro é uma cactácea xerófila, robusta, pouco ramificada, de cor verde-escura, armada de espinhos agudos; com flores grandes isoladas e altas. A proposta do trabalho foi elaborar barras de cereais com farinhas da casca e da polpa do facheiro e determinar as características microbiológicas e físico-químicas. Foram preparadas quatro formulações (5, 10, 15 e 20% de cada farinha, variando-se a quantidade adicionada à formulação básica das barras de cereais. Os resultados das análises microbiológicas atenderam aos padrões exigidos pela legislação vigente, apresentando resultados negativos para coliforme a 45° C e Salmonella sp. Nos resultados físico-químicos apresentaram baixos valores de umidade e cinzas, elevado teores de lipídeos e sólidos solúveis totais, quantidades razoáveis de proteínas. Dessa forma, as barras de cereais com adição de farinha do facheiro é um alimento que pode ser ingeridos pela população.Production and evaluation of the quality of cereal bars made with flour of facheiroAbstract: The cacti are an important element of the landscape, with succulent stems, covered with spines of different shapes, sizes and dimensions, along with other cactus species, form the typical landscape of the semi-arid region of Brazil. The facheiro is a cactaceous xerófila, rugged, sparsely branched, dark green color, armed with sharp thorns; with large isolated and tall flowers. The purpose of this study was to develop cereal bars with flour peel and facheiro pulp and determine the microbiological and physico-chemical characteristics. Four formulations (5, 10, 15 and 20% for each meal, varying the amount added to the basic formulation of the cereal bars. The

ESTUDO NUMÉRICO DE CONECTORES DE CISALHAMENTO EM BARRAS DE AÇO PARA VIGAS MISTAS DE AÇO E CONCRETO

OpenAIRE

Barbosa, Wallison Carlos de Souza; Chater, Latif C; e Cavalcante, Otávio R de Oliveira; Bezerra, Luciano Mendes

2017-01-01

Resumo. As estruturas mistas apresentam grandes vantagens quanto a aspectos estruturais e construtivos, sendo os conectores de cisalhamento determinantes para a obtenção da interação entre os materiais (aço e concreto). Este trabalho apresenta o desenvolvimento de um conector de cisalhamento com barras de aço CA50-A, proposto para uso em viga mista de aço e concreto. O conector proposto é de fácil execução e pode servir como alternativa viável ao uso dos conectores stud e ‘U’. Foi idealizada ...

LIMNOLOGY, LAKE BASINS, LAKE WATERS

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Petre GÂŞTESCU

2009-06-01

Full Text Available Limnology is a border discipline between geography, hydrology and biology, and is also closely connected with other sciences, from it borrows research methods. Physical limnology (the geography of lakes, studies lake biotopes, and biological limnology (the biology of lakes, studies lake biocoenoses. The father of limnology is the Swiss scientist F.A. Forel, the author of a three-volume entitled Le Leman: monographie limnologique (1892-1904, which focuses on the geology physics, chemistry and biology of lakes. He was also author of the first textbook of limnology, Handbuch der Seenkunde: allgemeine Limnologie,(1901. Since both the lake biotope and its biohydrocoenosis make up a single whole, the lake and lakes, respectively, represent the most typical systems in nature. They could be called limnosystems (lacustrine ecosystems, a microcosm in itself, as the American biologist St.A. Forbes put it (1887.

Aspectos bioecológicos de Arenaeus cribrarius (Lamarck (Decapoda, Portunidae da Praia da Barra da Lagoa, Florianópolis, Santa Catarina, Brasil Bioecological aspects of Arenaeus cribrarius (Lamarck (Decapoda, Portunidae from Praia da Barra da Lagoa, Florianópolis, Santa Catarina, Brasil

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Marcelo Gentil Avila

1996-01-01

Full Text Available The specimens of Arenaeus cribrarius (Lamarck, 1818 used in this study were collected in the locality of Barra da Lagoa beach, Florianópolis, Santa Catarina, Brazil, in the period of April/1991 to March/1992. In this area temperature and salinity values were observed. A total of 341 samples, that 184 were male and 157 were female were collectted. The maturacion sexual stadium were measured (cm and weightied (g. Expression of relation among weight of body (wt and width of carapace (wid was Wt=0,0567 Wid3,0494 on males and wt=0,074 Wid2,8795 on females. The relation length (Lt width (wid of carapace was Lt=0,4322. wid on males and Lt=0,4578. wid on females.

DNA barcodes for soil animal taxonomy Código de barras de DNA para a taxonomia de animais do solo

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Rodolphe Rougerie

2009-08-01

Full Text Available The biodiversity of soil communities remains very poorly known and understood. Soil biological sciences are strongly affected by the taxonomic crisis, and most groups of animals in that biota suffer from a strong taxonomic impediment. The objective of this work was to investigate how DNA barcoding - a novel method using a microgenomic tag for species identification and discrimination - permits better evaluation of the taxonomy of soil biota. A total of 1,152 barcode sequences were analyzed for two major groups of animals, collembolans and earthworms, which presented broad taxonomic and geographic sampling. Besides strongly reflecting the taxonomic impediment for both groups, with a large number of species-level divergent lineages remaining unnamed so far, the results also highlight a high level (15% of cryptic diversity within known species of both earthworms and collembolans. These results are supportive of recent local studies using a similar approach. Within an impeded taxonomic system for soil animals, DNA-assisted identification tools can facilitate and improve biodiversity exploration and description. DNA-barcoding campaigns are rapidly developing in soil animals and the community of soil biologists is urged to embrace these methods.A biodiversidade das comunidades do solo continua muito pouco conhecida e entendida. A biologia do solo é fortemente afetada pela crise taxonômica, e a maior parte dos grupos de animais dessa biota sofre forte impedimento taxonômico. O objetivo deste trabalho foi determinar como o código de barras de DNA - um método novo que usa uma etiqueta microgenômica para identificação e discriminação de espécies - permite uma melhor avaliação da taxonomia da biota edáfica. Foram analisadas 1.152 sequências de códigos de barras de dois grupos principais de animais, colêmbolos e minhocas, que apresentaram ampla amostragem taxonômica e geográfica. Além de refletir fortemente o impedimento taxonômico de

ANÁLISIS CINEMÁTICO Y DISEÑO DE UN MECANISMO DE CUATRO BARRAS PARA FALANGE PROXIMAL DE DEDO ANTROPOMÓRFICO

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Édgar Alfredo Portilla Flores

2010-01-01

Full Text Available En este artículo, se presenta el análisis cinemático y una metodología de diseño paramétrico de la falange proximal para un dedo antropomórfico1 de un grado de libertad. El diseño del mecanismo se lleva a cabo, tomando diez posiciones de la barra de salida del mismo. Se presenta la simulación dinámica, utilizando un modelo de CAD para comprobar la factibilidad de los resultados obtenidos por el mecanismo. Por último, se muestra el análisis comparativo entre los resultados de la cinemática obtenidos numéricamente y los experimentales.

Microplastic pollution in lakes and lake shoreline sediments - A case study on Lake Bolsena and Lake Chiusi (central Italy).

Science.gov (United States)

Fischer, Elke Kerstin; Paglialonga, Lisa; Czech, Elisa; Tamminga, Matthias

2016-06-01

Rivers and effluents have been identified as major pathways for microplastics of terrestrial sources. Moreover, lakes of different dimensions and even in remote locations contain microplastics in striking abundances. This study investigates concentrations of microplastic particles at two lakes in central Italy (Lake Bolsena, Lake Chiusi). A total number of six Manta Trawls have been carried out, two of them one day after heavy winds occurred on Lake Bolsena showing effects on particle distribution of fragments and fibers of varying size categories. Additionally, 36 sediment samples from lakeshores were analyzed for microplastic content. In the surface waters 2.68 to 3.36 particles/m(3) (Lake Chiusi) and 0.82 to 4.42 particles/m(3) (Lake Bolsena) were detected, respectively. Main differences between the lakes are attributed to lake characteristics such as surface and catchment area, depth and the presence of local wind patterns and tide range at Lake Bolsena. An event of heavy winds and moderate rainfall prior to one sampling led to an increase of concentrations at Lake Bolsena which is most probable related to lateral land-based and sewage effluent inputs. The abundances of microplastic particles in sediments vary from mean values of 112 (Lake Bolsena) to 234 particles/kg dry weight (Lake Chiusi). Lake Chiusi results reveal elevated fiber concentrations compared to those of Lake Bolsena what might be a result of higher organic content and a shift in grain size distribution towards the silt and clay fraction at the shallow and highly eutrophic Lake Chiusi. The distribution of particles along different beach levels revealed no significant differences. Copyright © 2016 Elsevier Ltd. All rights reserved.

ANÁLISE ARQUEOMÉTRICA DE PINTURAS RUPESTRES PRÉ-HISTÓRICAS DO SÍTIO TAMBORIL, BARRAS, PIAUÍ, BRASIL (Archaeometric Analysis of Prehistoric Rock Paintings from the Tamboril Site, Barras, Piauí, Brazil

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Luis Carlos Duarte Cavalcante

2016-03-01

Full Text Available O sítio arqueológico Tamboril, localizado na área rural do município de Barras, estado do Piauí, Brasil, é um bloco arenítico que apresenta um nicho decorado com pinturas rupestres, principalmente grafismos puros, motivos zoomórficos e carimbos de mãos humanas, pintados em diferentes tonalidades de vermelho. A conservação das pinturas é afetada por eflorescências salinas, resíduos decorrentes da atividade de insetos (como cupins e vespas e impacto humano (visitação sem acompanhamento de guias e atividade agrícola nas proximidades. A análise arqueométrica de pigmentos dessas pinturas rupestres foi realizada no laboratório com fluorescência de raios X por dispersão de energia e espectroscopia Mössbauer do 57Fe em geometria de retroespalhamento de raios γ à temperatura ambiente. Os teores de Fe (como Fe2O3 encontrados nas pinturas variam de 2,953(1 massa% a 17,23(1 massa%. Os parâmetros hiperfinos Mössbauer revelaram que o pigmento vermelho-escuro das pinturas rupestres é composto de hematita (αFe2O3 e de um Fe3+ (superparamagnético. Os teores de P (como P2O5 variam de 21,70(1 massa% a 25,92(1 massa% e foram atribuídos às eflorescências salinas e aos resíduos orgânicos de atividades de insetos que cobrem as inscrições pré-históricas. ENGLISH: The archaeological site known as Tamboril, located in the rural area of the municipality of Barras, Piauí State, Brazil, is a sandstone block that contains a niche decorated with rock paintings. These paintings are mainly composed of pure graphisms, zoomorphic motifs, and human handprints, painted in different tonalities of red. Their conservation has been affected by saline efflorescences, residues of insect activities (such as wasps and termites and human impact (unguided visitors and nearby agricultural activity. The archaeometric analysis of pigments from these rock paintings was performed in the laboratory with energy dispersive X-ray fluorescence and room

Phytoindication potential of dune species through predictive modeling at Jatobá beach, Barra dos Coqueiros, Sergipe

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Sindiany Suelen Caduda Santos

2015-04-01

Full Text Available O artigo objetiva investigar espécies endêmicas de dunas capazes de indicar a situação ambiental da área de Barra dos Coqueiros cogitada para criação de uma Unidade de Conservação, Sergipe, a partir do potencial fitogeográfico revelado pela modelagem de distribuição de espécies. Por meio do software MAXENT foram analisadas sete espécies endêmicas de dunas incipientes e semifixas. Os potenciais distributivos estabeleceram que a R. maritima, por sua taxa de dispersão próxima de um, é importante para recuperação de áreas litorâneas. Todavia, a I. imperati, com taxa de predição próxima de zero  é a fitoindicadora de vulnerabilidade/fragilidade. A pesquisa aponta que novas ações planejadas precisam ser efetivadas para a real conservação da biodiversidade em Sergipe.

Caracterização e avaliação sensorial de barra de cereais funcional de alto teor protéico e vitamínico Characterization and sensorial evaluation of functional cereal bar

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Daniela G.C. Freitas

2006-06-01

Full Text Available Barras de cereais foram introduzidas no mercado há cerca de uma década como alternativa "saudável" de confeito. Concomitantemente, alimentos como a soja, ricos em vitaminas e minerais e com propriedades antioxidantes vêm recebendo grande aplicação em produtos de alegação funcional, pois previnem contra doenças cardiovasculares e crônico-degenerativas. Considerando o crescimento do segmento de barra de cereais no setor de alimentos, desenvolveu-se uma formulação de barra de cereais de alto teor protéico e vitamínico, à base de proteína de soja texturizada, gérmen de trigo e aveia, enriquecida de ácido ascórbico e acetato de -tocoferol. As matérias-primas e a formulação final da barra de cereais foram submetidas a análises para caracterização e três formulações, variando o teor de ácido ascórbico, foram avaliadas quanto à preferência sensorial e intensidade ideal de doçura e acidez. A proteína de soja texturizada utilizada apresentou elevados teores dos oligossacarídeos rafinose e estaquiose (1,92 g/100 g e 4,66 g/100 g e de isoflavonas totais (283,49 mg/100 g se comparados ao grão, farinha integral e isolado protéico. A formulação final da barra de cereais apresentou 15,31% de proteína e elevado teor de vitamina E (118,0 mg/100 g e minerais como fósforo, ferro e manganês. A formulação adicionada de 1,1 g/100 g de ácido ascórbico obteve maior preferência sensorial diferindo das demais amostras (pCereal bars were introduced over a decade ago as a "healthy" alternative confectionery. Concomitantly, foods as soybean, with high vitamin and mineral levels and antioxidants properties come receiving great application in functional products, because they can prevent against chronic-degenerative illnesses of the heart. Considering the growth of the segment of cereal bars in the food sector, it was developed a formulation with high protein and vitamin levels cereal bar based on textured soy protein, wheat germ

Reproduction, food dynamics and exploitation level of Oreochromis niloticus (Perciformes: Cichlidae from artisanal fisheries in Barra Bonita Reservoir, Brazil

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José Luis Costa Novaes

2012-06-01

Full Text Available Nile tilapia (Oreochromis niloticus, which is exotic to South America, is the most common species caught in artisanal fisheries at the Barra Bonita Reservoir, Southeastern Brazil. This species is of great socioeconomic importance for the region and keeps active a population of about 500 fishers. In the present study we assess reproduction, food dynamics and level of exploitation of O. niloticus, caught by artisanal fisheries in the Barra Bonita Reservoir. Specimens were collected monthly, from July 2004-June 2005, and a total of 1 715 specimens were analyzed. Each specimen was examined to obtain biological and biometric data: standard length (cm, total weight (g, reproductive data (sex and stage of maturation, and stomach contents (empty, partly full, and full. We also estimated the sex ratio (by macroscopic observation of gonads, reproductive period (by ovarian development and seasonal average of gonadosomatic index in females, and feeding habits (by stomach contents. The possible relationship between abiotic factors and the reproductive period was statistically verified using Spearman’s Rank Correlation. The FiSAT (ELEFAN I package was used to assess growth parameters, mortality rates and to infer exploitation rate from standard length frequencies. The O. niloticus population had a sex ratio of 1.3:1 (M:F. Results indicated that ripe females were captured throughout the year, with a higher frequency during the winter-2004 (with a frequency of 59%, at a mean temperature of 20.5°C, and in spring-2004 (with a frequency of 60.5% at a mean temperature of 21.18°C. The GSI mean values obtained by season were: winter-2004: 1.71; spring-2004: 1.72; summer-2005: 0.80, and autumn-2005: 1.19. The Spearman correlation indicated positive values with respect to pH, dissolved oxygen, electric conductivity, transparency and chlorophyll a, and negative values with respect to temperature, accumulated rainfall and altimetric benchmark. The main food items

O USO DE BARRA OU HALTERE NÃO ALTERA A ATIVAÇÃO MUSCULAR DURANTE O EXERCÍCIO PULLOVER

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Yuri de Almeida Costa Campos

Full Text Available RESUMO Introdução: Inúmeras variações de exercícios têm sido aplicadas nas rotinas de treinamento de força, com o objetivo de otimizar os ganhos de força e hipertrofia e, entre os exercícios usados, podemos destacar o pullover. Objetivo: Comparar a atividade eletromiográfica da parte clavicular do músculo peitoral maior (PMC, parte esternocostal do peitoral maior (PME, cabeça longa do tríceps braquial (TBL, do deltoide anterior (DA, deltoide posterior (DP, latíssimo do dorso (LD e serrátil anterior (SA entre os exercícios pullover barra (PB e pullover haltere (PH. Método: Participaram do estudo 11 homens treinados (idade, 24,50 ± 4,34 anos; percentual de gordura = 13,63 ± 1,94; estatura = 1,76 ± 0,04 m; massa corporal total = 73,12 ± 6,10 kg. A primeira fase do estudo consistiu em avaliações antropométricas e teste e re-teste de 10 repetições máximas (RM. A segunda fase do estudo foi composta pela coleta dos sinais eletromiográficos nos exercícios propostos. Para tal, foi realizada uma série com cargas ajustadas a 90% de 10 RM. Para verificar as diferenças na ativação dos respectivos músculos estudados entre os exercícios PB e PH adotou-se o teste t de Student pareado para amostras dependentes. Resultados: Não foram observadas mudanças na ativação de nenhum dos músculos analisados nos exercícios propostos (P > 0,05. Conclusão: Concluiu-se que a realização do exercício pullover com barra ou com o haltere não altera a participação/ativação dos músculos envolvidos.

Diseño de proceso para el desarrollo de barras energéticas como subproducto en la obtención de leche saborizada de soya

OpenAIRE

Gamboa Valarezo, Vannia; Costa, Ana Maria

2009-01-01

El grano de soya es ampliamente reconocido por su elevado contenido en nutrientes. Durante el proceso de elaboración de la leche de soya el okara o pulpa residual del proceso representó del 20 a 25 por ciento del desperdicio cuyo alto valor nutricional y energético fue aprovechado. En el presente trabajo se propuso aprovechar integralmente el grano de soya, dando valor agregado a la fase líquida donde se obtuvo leche saborizada de soya y, a partir del desperdicio se obtuvieron barras ene...

Conhecimento tradicional das marisqueiras de Barra Grande, área de proteção ambiental do delta do Rio Parnaíba, Piauí, Brasil

OpenAIRE

Freitas, Simone Tupinambá; Pamplin, Paulo Augusto Zaitune; Legat, Jefferson; Fogaça, Fabíola Helena dos Santos; Barros, Roseli Farias Melo de

2012-01-01

Na comunidade de Barra Grande localizada no litoral do Piauí, as mulheres dos pescadores, conhecidas localmente como marisqueiras, extraem do manguezal vários tipos de moluscos para comercialização e em maior escala para a subsistência. Dados sobre a atividade de mariscagem, conceitos de conservação e aspectos socioeconômicos do contexto em que ocorre a atividade de cata dos moluscos, foram revelados após a aplicação de protocolos estruturados e semiestruturados. O molusco bivalve Anomalocard...

Terrestrial CDOM in Lakes of Yamal Peninsula: Connection to Lake and Lake Catchment Properties

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Yury Dvornikov

2018-01-01

Full Text Available In this study, we analyze interactions in lake and lake catchment systems of a continuous permafrost area. We assessed colored dissolved organic matter (CDOM absorption at 440 nm (a(440CDOM and absorption slope (S300–500 in lakes using field sampling and optical remote sensing data for an area of 350 km2 in Central Yamal, Siberia. Applying a CDOM algorithm (ratio of green and red band reflectance for two high spatial resolution multispectral GeoEye-1 and Worldview-2 satellite images, we were able to extrapolate the a(λCDOM data from 18 lakes sampled in the field to 356 lakes in the study area (model R2 = 0.79. Values of a(440CDOM in 356 lakes varied from 0.48 to 8.35 m−1 with a median of 1.43 m−1. This a(λCDOM dataset was used to relate lake CDOM to 17 lake and lake catchment parameters derived from optical and radar remote sensing data and from digital elevation model analysis in order to establish the parameters controlling CDOM in lakes on the Yamal Peninsula. Regression tree model and boosted regression tree analysis showed that the activity of cryogenic processes (thermocirques in the lake shores and lake water level were the two most important controls, explaining 48.4% and 28.4% of lake CDOM, respectively (R2 = 0.61. Activation of thermocirques led to a large input of terrestrial organic matter and sediments from catchments and thawed permafrost to lakes (n = 15, mean a(440CDOM = 5.3 m−1. Large lakes on the floodplain with a connection to Mordy-Yakha River received more CDOM (n = 7, mean a(440CDOM = 3.8 m−1 compared to lakes located on higher terraces.

Sanctuaries for lake trout in the Great Lakes

Science.gov (United States)

Stanley, Jon G.; Eshenroder, Randy L.; Hartman, Wilbur L.

1987-01-01

Populations of lake trout, severely depleted in Lake Superior and virtually extirpated from the other Great Lakes because of sea lamprey predation and intense fishing, are now maintained by annual plantings of hatchery-reared fish in Lakes Michigan, Huron, and Ontario and parts of Lake Superior. The extensive coastal areas of the Great Lakes and proximity to large populations resulted in fishing pressure on planted lake trout heavy enough to push annual mortality associated with sport and commercial fisheries well above the critical level needed to reestablish self-sustaining stocks. The interagency, international program for rehabilitating lake trout includes controlling sea lamprey abundance, stocking hatchery-reared lake trout, managing the catch, and establishing sanctuaries where harvest is prohibited. Three lake trout sanctuaries have been established in Lake Michigan: the Fox Island Sanctuary of 121, 500 ha, in the Chippewa-Ottawa Treaty fishing zone in the northern region of the lake; the Milwaukee Reef Sanctuary of 160, 000 ha in midlake, in boundary waters of Michigan and Wisconsin; and Julian's Reef Sanctuary of 6, 500 ha, in Illinois waters. In northern Lake Huron, Drummond Island Sanctuary of 55, 000 ha is two thirds in Indian treaty-ceded waters in Michigan and one third in Ontario waters of Canada. A second sanctuary, Six Fathom Bank-Yankee Reef Sanctuary, in central Lake Huron contains 168, 000 ha. Sanctuary status for the Canadian areas remains to be approved by the Provincial government. In Lake Superior, sanctuaries protect the spawning grounds of Gull Island Shoal (70, 000 ha) and Devils Island Shoal (44, 000 ha) in Wisconsin's Apostle Island area. These seven sanctuaries, established by the several States and agreed upon by the States, Indian tribes, the U.S. Department of the Interior, and the Province of Ontario, contribute toward solving an interjurisdictional fishery problem.

Sediment failures within the Peach Slide (Barra Fan, NE Atlantic Ocean) and relation to the history of the British-Irish Ice Sheet

Science.gov (United States)

Owen, Matthew J.; Maslin, Mark A.; Day, Simon J.; Long, David

2018-05-01

The Peach Slide is the largest known submarine mass movement on the British continental margin and is situated on the northern flank of the glacigenic Barra Fan. The Barra Fan is located on the northwest British continental margin and is subject to cyclonic ocean circulation, with distinct differences between the circulation during stadial and inter-stadial periods. The fan has experienced growth since continental uplift during the mid-Pliocene, with the majority of sediments deposited during the Pleistocene when the fan was a major depocentre for the British-Irish Ice Sheet (BIIS). Surface and shallow sub-surface morphology of the fan has been mapped using newly digitised archival paper pinger and deep towed boomer sub-bottom profile records, side scan sonar and multibeam echosounder data. This process has allowed the interpretation and mapping of a number of different seismic facies, including: contourites, hemipelagites and debrites. Development of a radiocarbon based age model for the seismic stratigraphy constrains the occurrence of two periods of slope failure: the first at circa 21 ka cal BP, shortly after the BIIS's maximum advance during the deglaciation of the Hebrides Ice Stream; and the second between 12 and 11 ka cal BP at the termination of the Younger Dryas stadial. Comparison with other mass movement events, which have similar geological and oceanographic settings, suggests that important roles are played by contouritic and glacigenic sedimentation, deposited in inter-stadial and stadial periods respectively when different thermohaline regimes and sediment sources dominate. The effect of this switch in sedimentation is to rapidly deposit thick, low permeability, glacigenic layers above contourite and hemipelagite units. This process potentially produced excess pore pressure in the fan sediments and would have increased the likelihood of sediment failure via reduced shear strength and potential liquefaction.

Evolution of alkaline lakes - Lake Van case study

Science.gov (United States)

Tillman Meyer, Felix; Viehberg, Finn; Bahroun, Sonya; Wolf, Annabel; Immenhauser, Adrian; Kwiecien, Ola

2017-04-01

Lake Van in Eastern Anatolia (Turkey) is the largest terminal soda lake on Earth. The lake sedimentary profile covers ca. 600 ka (Stockhecke et al. 2014) Based on lithological changes, the presence of freshwater microfossils and close-to-freshwater pH value in the pore water, members of ICDP PALEOVAN concluded that Lake Van might have started as an open lake. Here we show paleontological and geochemical evidence in favour of this idea and constrain the time, when Lake Van likely transformed into a closed lake. Additionally we provide the first conceptual model of how this closure may have happened. Our archives of choice are inorganic and biogenic carbonates, separated by wet sieving. We identified microfossil assemblages (fraction > 125 µm) and performed high-resolution oxygen isotope (delta18O) and elemental (Mg/Ca, Sr/Ca) analyses of the fraction plants growing in the photic zone as food supply. These two aspects point to an increasing salinity in a shallowing lake. The delta18O values of inorganic carbonates are relatively low during the initial phase of Lake Van and increase abruptly (ca. 7‰) after 530 ka BP. At approximately the same time combination of Sr/Ca and Mg/Ca data suggest first occurrence of aragonite. Again, these findings suggest geochemical changes of the lake water concurrent with transition documented by microfossils. Comparison between Lake Van and Lake Ohrid (Lacey et al. 2016) delta18O data, precludes regional climate change (e.g.: increased evaporation) as the main driver of observed changes. With no evidence for increased volcanic or tectonic activity (e.g.: tephra layers, deformation structures, slumping) in the Lake Van sedimentary profile around 530 ka, it seems unlikely that a pyroclastic flow blocked the outflow of the lake. Alternatively, a portion of inflow has been diverged which might have caused a change in the hydrological balance and lake level falling below its outlet. However, as no geomorphological data confirming this

Bathymetry of Lake Erie and Lake Saint Clair

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry of Lake Erie and Lake Saint Clair has been compiled as a component of a NOAA project to rescue Great Lakes lake floor geological and geophysical data and...

Cytogenetics of the Brazilian whiptail lizard Cnemidophorus littoralis (Teiidae) from a restinga area (Barra de Maricá) in Southeastern Brazil.

Science.gov (United States)

Peccinini-Seale, D; Rocha, C F D; Almeida, T M B; Araújo, A F B; De Sena, M A

2004-08-01

Chromosomes of Cnemidophorus littoralis, a new species of teiid lizard recently described, were studied. The animals are from a restinga area in Barra de Maricá, RJ. The karyotype presents a diploid number of 2n = 46 chromosomes and a chromosomal sex determination mechanism of the type XX:XY. Nucleolar organizer regions, Ag-NORs, are at the sixth pair of chromosomes; there is variability of size and number of the Ag-stained nucleoli on the 50 interphase nuclei for each specimen analyzed. These nucleoli are related to NOR patterns that also demonstrated variability in size and number. This paper presents the first description of the karyotype of Cnemidophorus littoralis and of a chromosomal sex determination mechanism of the XX:XY type in the genus Cnemidophorus from Southeastern Brazil.

Lake whitefish diet, condition, and energy density in Lake Champlain and the lower four Great Lakes following dreissenid invasions

Science.gov (United States)

Herbst, Seth J.; Marsden, J. Ellen; Lantry, Brian F.

2013-01-01

Lake Whitefish Coregonus clupeaformis support some of the most valuable commercial freshwater fisheries in North America. Recent growth and condition decreases in Lake Whitefish populations in the Great Lakes have been attributed to the invasion of the dreissenid mussels, zebra mussels Dreissena polymorpha and quagga mussels D. bugensis, and the subsequent collapse of the amphipod, Diporeia, a once-abundant high energy prey source. Since 1993, Lake Champlain has also experienced the invasion and proliferation of zebra mussels, but in contrast to the Great Lakes, Diporeia were not historically abundant. We compared the diet, condition, and energy density of Lake Whitefish from Lake Champlain after the dreissenid mussel invasion to values for those of Lake Whitefish from Lakes Michigan, Huron, Erie, and Ontario. Lake Whitefish were collected using gill nets and bottom trawls, and their diets were quantified seasonally. Condition was estimated using Fulton's condition factor (K) and by determining energy density. In contrast to Lake Whitefish from some of the Great Lakes, those from Lake Champlain Lake Whitefish did not show a dietary shift towards dreissenid mussels, but instead fed primarily on fish eggs in spring, Mysis diluviana in summer, and gastropods and sphaeriids in fall and winter. Along with these dietary differences, the condition and energy density of Lake Whitefish from Lake Champlain were high compared with those of Lake Whitefish from Lakes Michigan, Huron, and Ontario after the dreissenid invasion, and were similar to Lake Whitefish from Lake Erie; fish from Lakes Michigan, Huron, and Ontario consumed dreissenids, whereas fish from Lake Erie did not. Our comparisons of Lake Whitefish populations in Lake Champlain to those in the Great Lakes indicate that diet and condition of Lake Champlain Lake Whitefish were not negatively affected by the dreissenid mussel invasion.

Glacial lake inventory and lake outburst potential in Uzbekistan.

Science.gov (United States)

Petrov, Maxim A; Sabitov, Timur Y; Tomashevskaya, Irina G; Glazirin, Gleb E; Chernomorets, Sergey S; Savernyuk, Elena A; Tutubalina, Olga V; Petrakov, Dmitriy A; Sokolov, Leonid S; Dokukin, Mikhail D; Mountrakis, Giorgos; Ruiz-Villanueva, Virginia; Stoffel, Markus

2017-08-15

Climate change has been shown to increase the number of mountain lakes across various mountain ranges in the World. In Central Asia, and in particular on the territory of Uzbekistan, a detailed assessment of glacier lakes and their evolution over time is, however lacking. For this reason we created the first detailed inventory of mountain lakes of Uzbekistan based on recent (2002-2014) satellite observations using WorldView-2, SPOT5, and IKONOS imagery with a spatial resolution from 2 to 10m. This record was complemented with data from field studies of the last 50years. The previous data were mostly in the form of inventories of lakes, available in Soviet archives, and primarily included localized in-situ data. The inventory of mountain lakes presented here, by contrast, includes an overview of all lakes of the territory of Uzbekistan. Lakes were considered if they were located at altitudes above 1500m and if lakes had an area exceeding 100m 2 . As in other mountain regions of the World, the ongoing increase of air temperatures has led to an increase in lake number and area. Moreover, the frequency and overall number of lake outburst events have been on the rise as well. Therefore, we also present the first outburst assessment with an updated version of well-known approaches considering local climate features and event histories. As a result, out of the 242 lakes identified on the territory of Uzbekistan, 15% are considered prone to outburst, 10% of these lakes have been assigned low outburst potential and the remainder of the lakes have an average level of outburst potential. We conclude that the distribution of lakes by elevation shows a significant influence on lake area and hazard potential. No significant differences, by contrast, exist between the distribution of lake area, outburst potential, and lake location with respect to glaciers by regions. Copyright © 2017 Elsevier B.V. All rights reserved.

High visceral leishmaniasis mortality rate in Barra Mansa, a new area of visceral leishmaniasis transmission in the State of Rio de Janeiro, Brazil

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Maria Inês Fernandes Pimentel

2014-07-01

Full Text Available Introduction Nine cases of visceral leishmaniasis occurred recently in Barra Mansa, State of Rio de Janeiro, with a high mortality rate. Methods We reviewed the medical records of the patients. Results Eight were male; 7 were adults. Patients who died progressed to death quickly and presented with aggravating factors: systemic steroid therapy before diagnosis, bleeding, severe liver involvement, infection, and/or refusal to receive transfusion. Conclusions We warn clinicians to be aware of the emergence of visceral leishmaniasis in new areas and to keep in mind the possibility of atypical clinical pictures and aggravating factors, so timely diagnosis can be made and prompt and adequate treatment can be initiated.

Lake-level frequency analysis for Devils Lake, North Dakota

Science.gov (United States)

Wiche, Gregg J.; Vecchia, Aldo V.

1996-01-01

Two approaches were used to estimate future lake-level probabilities for Devils Lake. The first approach is based on an annual lake-volume model, and the second approach is based on a statistical water mass-balance model that generates seasonal lake volumes on the basis of seasonal precipitation, evaporation, and inflow. Autoregressive moving average models were used to model the annual mean lake volume and the difference between the annual maximum lake volume and the annual mean lake volume. Residuals from both models were determined to be uncorrelated with zero mean and constant variance. However, a nonlinear relation between the residuals of the two models was included in the final annual lakevolume model.Because of high autocorrelation in the annual lake levels of Devils Lake, the annual lake-volume model was verified using annual lake-level changes. The annual lake-volume model closely reproduced the statistics of the recorded lake-level changes for 1901-93 except for the skewness coefficient. However, the model output is less skewed than the data indicate because of some unrealistically large lake-level declines. The statistical water mass-balance model requires as inputs seasonal precipitation, evaporation, and inflow data for Devils Lake. Analysis of annual precipitation, evaporation, and inflow data for 1950-93 revealed no significant trends or long-range dependence so the input time series were assumed to be stationary and short-range dependent.Normality transformations were used to approximately maintain the marginal probability distributions; and a multivariate, periodic autoregressive model was used to reproduce the correlation structure. Each of the coefficients in the model is significantly different from zero at the 5-percent significance level. Coefficients relating spring inflow from one year to spring and fall inflows from the previous year had the largest effect on the lake-level frequency analysis.Inclusion of parameter uncertainty in the model

Lake trout in northern Lake Huron spawn on submerged drumlins

Science.gov (United States)

Riley, Stephen C.; Binder, Thomas; Wattrus, Nigel J.; Faust, Matthew D.; Janssen, John; Menzies, John; Marsden, J. Ellen; Ebener, Mark P.; Bronte, Charles R.; He, Ji X.; Tucker, Taaja R.; Hansen, Michael J.; Thompson, Henry T.; Muir, Andrew M.; Krueger, Charles C.

2014-01-01

Recent observations of spawning lake trout Salvelinus namaycush near Drummond Island in northern Lake Huron indicate that lake trout use drumlins, landforms created in subglacial environments by the action of ice sheets, as a primary spawning habitat. From these observations, we generated a hypothesis that may in part explain locations chosen by lake trout for spawning. Most salmonines spawn in streams where they rely on streamflows to sort and clean sediments to create good spawning habitat. Flows sufficient to sort larger sediment sizes are generally lacking in lakes, but some glacial bedforms contain large pockets of sorted sediments that can provide the interstitial spaces necessary for lake trout egg incubation, particularly if these bedforms are situated such that lake currents can penetrate these sediments. We hypothesize that sediment inclusions from glacial scavenging and sediment sorting that occurred during the creation of bedforms such as drumlins, end moraines, and eskers create suitable conditions for lake trout egg incubation, particularly where these bedforms interact with lake currents to remove fine sediments. Further, these bedforms may provide high-quality lake trout spawning habitat at many locations in the Great Lakes and may be especially important along the southern edge of the range of the species. A better understanding of the role of glacially-derived bedforms in the creation of lake trout spawning habitat may help develop powerful predictors of lake trout spawning locations, provide insight into the evolution of unique spawning behaviors by lake trout, and aid in lake trout restoration in the Great Lakes.

Lake sturgeon population characteristics in Rainy Lake, Minnesota and Ontario

Science.gov (United States)

Adams, W.E.; Kallemeyn, L.W.; Willis, D.W.

2006-01-01

Rainy Lake contains a native population of lake sturgeon Acipenser fulvescens that has been largely unstudied. The aims of this study were to document the population characteristics of lake sturgeon in Rainy Lake and to relate environmental factors to year-class strength for this population. Gill-netting efforts throughout the study resulted in the capture of 322 lake sturgeon, including 50 recaptures. Lake sturgeon in Rainy Lake was relatively plump and fast growing compared with a 32-population summary. Population samples were dominated by lake sturgeon between 110 and 150 cm total length. Age–structure analysis of the samples indicated few younger (<10 years) lake sturgeon, but the smallest gill net mesh size used for sampling was 102 mm (bar measure) and would not retain small sturgeon. Few lake sturgeon older than age 50 years were captured, and maximum age of sampled fish was 59 years. Few correlations existed between lake sturgeon year-class indices and both annual and monthly climate variables, except that mean June air temperature was positively correlated with year-class strength. Analysis of Rainy Lake water elevation and resulting lake sturgeon year-class strength indices across years yielded consistent but weak negative correlations between late April and early June, when spawning of lake sturgeon occurs. The baseline data collected in this study should allow Rainy Lake biologists to establish more specific research questions in the future.

Zooplankton communities in a large prealpine lake, Lake Constance: comparison between the Upper and the Lower Lake

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Gerhard MAIER

2005-08-01

Full Text Available The zooplankton communities of two basins of a large lake, Lake Constance, were compared during the years 2002 and 2003. The two basins differ in morphology, physical and chemical conditions. The Upper Lake basin has a surface area of 470 km2, a mean depth of 100 and a maximum depth of 250 m; the Lower Lake basin has a surface area of 62 km2, a mean depth of only 13 and a maximum depth of 40 m. Nutrient, chlorophyll-a concentrations and mean temperatures are somewhat higher in the Lower than in the Upper Lake. Total abundance of rotifers (number per m2 lake surface was higher and rotifer development started earlier in the year in the Lower than in the Upper Lake. Total abundance of crustaceans was higher in the Upper Lake in the year 2002; in the year 2003 no difference in abundance could be detected between the lake basins, although in summer crustacean abundance was higher in the Lower than in the Upper Lake. Crustacean communities differed significantly between lake basins while there was no apparent difference in rotifer communities. In the Lower Lake small crustaceans, like Bosmina spp., Ceriodaphnia pulchella and Thermocyclops oithonoides prevailed. Abundance (number per m2 lake surface of predatory cladocerans, large daphnids and large copepods was much lower in the Lower than in the Upper Lake, in particular during the summer months. Ordination with nonmetric multidimensional scaling (NMS separated communities of both lakes along gradients that correlated with temperature and chlorophyll a concentration. Clutches of copepods were larger in the Lower than in the Upper Lake. No difference could be detected in clutch size of large daphnids between lake basins. Our results show that zooplankton communities in different basins of Lake Constance can be very different. They further suggest that the lack of large crustaceans in particular the lack of large predatory cladocerans in the Lower Lake can have negative effects on growth and

Lake trout rehabilitation in Lake Erie: a case history

Science.gov (United States)

Cornelius, Floyd C.; Muth, Kenneth M.; Kenyon, Roger

1995-01-01

Native lake trout (Salvelinus namaycush) once thrived in the deep waters of eastern Lake Erie. The impact of nearly 70 years of unregulated exploitation and over 100 years of progressively severe cultural eutrophication resulted in the elimination of lake trout stocks by 1950. Early attempts to restore lake trout by stocking were unsuccessful in establishing a self-sustaining population. In the early 1980s, New York's Department of Environmental Conservation, Pennsylvania's Fish and Boat Commission, and the U.S. Fish and Wildlife Service entered into a cooperative program to rehabilitate lake trout in the eastern basin of Lake Erie. After 11 years of stocking selected strains of lake trout in U.S. waters, followed by effective sea lamprey control, lake trout appear to be successfully recolonizing their native habitat. Adult stocks have built up significantly and are expanding their range in the lake. Preliminary investigations suggest that lake trout reproductive habitat is still adequate for natural reproduction, but natural recruitment has not been documented. Future assessments will be directed toward evaluation of spawning success and tracking age-class cohorts as they move through the fishery.

Microbiology of Lonar Lake and other soda lakes

Science.gov (United States)

Paul Antony, Chakkiath; Kumaresan, Deepak; Hunger, Sindy; Drake, Harold L; Murrell, J Colin; Shouche, Yogesh S

2013-01-01

Soda lakes are saline and alkaline ecosystems that are believed to have existed throughout the geological record of Earth. They are widely distributed across the globe, but are highly abundant in terrestrial biomes such as deserts and steppes and in geologically interesting regions such as the East African Rift valley. The unusual geochemistry of these lakes supports the growth of an impressive array of microorganisms that are of ecological and economic importance. Haloalkaliphilic Bacteria and Archaea belonging to all major trophic groups have been described from many soda lakes, including lakes with exceptionally high levels of heavy metals. Lonar Lake is a soda lake that is centered at an unusual meteorite impact structure in the Deccan basalts in India and its key physicochemical and microbiological characteristics are highlighted in this article. The occurrence of diverse functional groups of microbes, such as methanogens, methanotrophs, phototrophs, denitrifiers, sulfur oxidizers, sulfate reducers and syntrophs in soda lakes, suggests that these habitats harbor complex microbial food webs that (a) interconnect various biological cycles via redox coupling and (b) impact on the production and consumption of greenhouse gases. Soda lake microorganisms harbor several biotechnologically relevant enzymes and biomolecules (for example, cellulases, amylases, ectoine) and there is the need to augment bioprospecting efforts in soda lake environments with new integrated approaches. Importantly, some saline and alkaline lake ecosystems around the world need to be protected from anthropogenic pressures that threaten their long-term existence. PMID:23178675

Holocene Lake-Level Fluctuations of Lake Aricota, Southern Peru

Science.gov (United States)

Placzek, Christa; Quade, Jay; Betancourt, Julio L.

2001-09-01

Lacustrine deposits exposed around Lake Aricota, Peru (17° 22‧S), a 7.5-km2 lake dammed by debris flows, provide a middle to late Holocene record of lake-level fluctuations. Chronological context for shoreline deposits was obtained from radiocarbon dating of vascular plant remains and other datable material with minimal 14C reservoir effects (<350 yr). Diatomites associated with highstands several meters above the modern lake level indicate wet episodes. Maximum Holocene lake level was attained before 6100 14C yr B.P. and ended ∼2700 14C yr B.P. Moderately high lake levels occurred at 1700 and 1300 14C yr B.P. The highstand at Lake Aricota during the middle Holocene is coeval with a major lowstand at Lake Titicaca (16°S), which is only 130 km to the northeast and shares a similar climatology. Comparisons with other marine and terrestrial records highlight emerging contradictions over the nature of mid-Holocene climate in the central Andes.

The diversity of benthic mollusks of Lake Victoria and Lake Burigi ...

African Journals Online (AJOL)

Molluscan diversity, abundance and distribution in sediments of Lake Victoria and its satellite lake, Lake Burigi, were investigated. The survey was carried out in January and February 2002 for Lake Victoria and in March and April 2002 for Lake Burigi. Ten genera were recorded from four zones of Lake Victoria while only ...

Study of Fluidized-Bed Control Rods; Etude de Barres de Controle Fluidisees; Izuchenie reguliruyushchej sistemy, ispol'zuyushchej suspenziyu pogloshchayushchikh chastits; Estudio Sobre Barras de Control de Lecho Fluidificado

Energy Technology Data Exchange (ETDEWEB)

Blair, D. J. [General Nuclear Engineering Corporation, Dunedin, FL (United States); Driscoll, M. J.; Dalton, G. R.; Parkinson, T. F. [Department of Nuclear Engineering, University of Florida, Gainesville, FL (United States)

1964-06-15

'obtenir des caracteristiques hydrauliques et nucleaires acceptables. Il s'est avere possible de controler des reacteurs de faible puissance en utilisant des barres de controle fluidisees a transmission ou a reflection. Il est apparu, en outre, que la formule FBCR a de bonnes caracteristiques de controle qui peuvent etre calculees par les methodes theoriques habituelles. Pour les reacteurs de grande puissance et a temperature elevee, il faudra obtenir des renseignements supplementaires sur les caracteristiques du materiau en particules. L'un des grands avantages de la formule FBCR est d'offrir la possibilite de modifier le flux axial soit en utilisant des particules de dimensions ou d'absorption variables soit en donnant une forme appropriee a la section horizontale de la barre. (author) [Spanish] En ocasiones anteriores se habia propuesto regular los reactores nucleares utilizando barras de control de lecho fluidificado (FBCR), pero pese a sus ventajas aparentes con respecto a los sistemas electromecanicos, no se les ha prestado mucha atencion. Con arreglo al concepto FBCR, el sistema de control del reactor se convierte en un dispositivo de regulacion de caudal por medio de bombas de velocidad variable o de valvulas accionadas por motor en el circuito principal de refrigerante. Como alternativa, pueden utilizarse tuberias de desviacion en el cuerpo, analogas a los sistemas de control que ahora se construyen para los reactores de lecho fluidificado. Las barras FBCR ofrecen, entre otras, las siguientes ventajas: 1. Puede suprimirse la mayor parte de los orificios de la parte superior del recipiente de presion y se simplifica la recarga de combustible. 2. Toda disminucion anomala del caudal provoca una interrupcion instantanea de caracter automatico. 3. El flujo axial puede conformarse mediante el empleo de canales de perfil especial o de particulas de tamaflo variable. 4. Es posible reducir la intensificacion del flujo en el espacio de agua al extraer parcialmente la barra de

Lake Morphometry for NHD Lakes in Great Lakes Region 4 HUC

Data.gov (United States)

U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

Evaluación físico - químico del dulce de leche saborizado en barra a diferentes temperaturas de conservación Empresa de Productos Lácteos Bayamo

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Adriana Lucia Rodríguez Rodríguez

2015-09-01

Full Text Available La investigación se desarrolló con el propósito de diagnosticar las causas de afectaciones microbiológicas en el dulce de leche saborizado en barra antes de los 7 días de garantía, conservado a temperatura ambiente en los puntos de venta, deteriorando los parámetros de calidad del producto, por lo que se procedió a la realización de un diagnóstico en estos puntos donde se comercializa el surtido, relacionando los factores temperatura – humedad, así como entrevistas realizadas a clientes y trabajadores que allí laboran. En la industria también se realizó un diagnóstico que incluyó desde el estudio minucioso y análisis físicos-químicos, organolépticos y microbiológicos de todas las materias primas y materiales que se utilizan en la elaboración del dulce de leche, hasta el control de calidad del producto terminado expuesto a diferentes valores de temperatura y humedad relativa, con observación diaria de la muestras en vida estate y análisis realizados en intervalos de 7 días, determinando que la exposición del producto a temperatura ambiente propicia el desarrollo microbiano y que el menor valor de temperatura estudiado 18 0C, garantiza una durabilidad en el dulce de leche saborizado en barra de 30 días.

Spatial and temporal genetic diversity of lake whitefish (Coregonus clupeaformis (Mitchill)) from Lake Huron and Lake Erie

Science.gov (United States)

Stott, Wendylee; Ebener, Mark P.; Mohr, Lloyd; Hartman, Travis; Johnson, Jim; Roseman, Edward F.

2013-01-01

Lake whitefish (Coregonus clupeaformis (Mitchill)) are important commercially, culturally, and ecologically in the Laurentian Great Lakes. Stocks of lake whitefish in the Great Lakes have recovered from low levels of abundance in the 1960s. Reductions in abundance, loss of habitat and environmental degradation can be accompanied by losses of genetic diversity and overall fitness that may persist even as populations recover demographically. Therefore, it is important to be able to identify stocks that have reduced levels of genetic diversity. In this study, we investigated patterns of genetic diversity at microsatellite DNA loci in lake whitefish collected between 1927 and 1929 (historical period) and between 1997 and 2005 (contemporary period) from Lake Huron and Lake Erie. Genetic analysis of lake whitefish from Lakes Huron and Erie shows that the amount of population structuring varies from lake to lake. Greater genetic divergences among collections from Lake Huron may be the result of sampling scale, migration patterns and demographic processes. Fluctuations in abundance of lake whitefish populations may have resulted in periods of increased genetic drift that have resulted in changes in allele frequencies over time, but periodic genetic drift was not severe enough to result in a significant loss of genetic diversity. Migration among stocks may have decreased levels of genetic differentiation while not completely obscuring stock boundaries. Recent changes in spatial boundaries to stocks, the number of stocks and life history characteristics of stocks further demonstrate the potential of coregonids for a swift and varied response to environmental change and emphasise the importance of incorporating both spatial and temporal considerations into management plans to ensure that diversity is preserved.

Niveles de impulsividad y riesgo de alcoholismo en personas pertenecientes a barras bravas en la ciudad de Ibagué - Colombia

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José Alonso Andrade Salazar

2014-01-01

Full Text Available El objetivo de este trabajo es determinar la relación entre niveles de impulsividad y riesgo de alcoholismo en adultos pertenecientes a “barras bravas” en la ciudad de Ibagué (Tolima a partir de la aplicación del test de CAGE, la Escala de Impulsividad de Plutchik (EI y una ficha de caracterización sociodemográfica. Se utilizó un modelo correlacional de corte transversal. Los hallazgos evidencian niveles bajos (78% y promedios de impulsividad (20%. El 28% no presenta problemas relacionados con el alcohol, mientras que el 36% tiene indicios de consumo y el restante 36% dependencia alcohólica. Se hallaron correlaciones bajas entre las puntuaciones, la correlación significativa fue de tipo directamente proporcional entre edad y riesgo de alcoholismo (r= 0,287; p= 0.43, lo que indica que a mayor edad mayor es el riesgo de alcoholismo.

Energy density of lake whitefish Coregonus clupeaformis in Lakes Huron and Michigan

Science.gov (United States)

Pothoven, S.A.; Nalepa, T.F.; Madenjian, C.P.; Rediske, R.R.; Schneeberger, P.J.; He, J.X.

2006-01-01

We collected lake whitefish Coregonus clupeaformis off Alpena and Tawas City, Michigan, USA in Lake Huron and off Muskegon, Michigan USA in Lake Michigan during 2002–2004. We determined energy density and percent dry weight for lake whitefish from both lakes and lipid content for Lake Michigan fish. Energy density increased with increasing fish weight up to 800 g, and then remained relatively constant with further increases in fish weight. Energy density, adjusted for weight, was lower in Lake Huron than in Lake Michigan for both small (≤800 g) and large fish (>800 g). Energy density did not differ seasonally for small or large lake whitefish or between adult male and female fish. Energy density was strongly correlated with percent dry weight and percent lipid content. Based on data from commercially caught lake whitefish, body condition was lower in Lake Huron than Lake Michigan during 1981–2003, indicating that the dissimilarity in body condition between the lakes could be long standing. Energy density and lipid content in 2002–2004 in Lake Michigan were lower than data for comparable sized fish collected in 1969–1971. Differences in energy density between lakes were attributed to variation in diet and prey energy content as well as factors that affect feeding rates such as lake whitefish density and prey abundance.

Effects of lake trout refuges on lake whitefish and cisco in the Apostle Islands Region of Lake Superior

Science.gov (United States)

Zuccarino-Crowe , Chiara M.; Taylor, William W.; Hansen, Michael J.; Seider, Michael J.; Krueger, Charles C.

2016-01-01

Lake trout refuges in the Apostle Islands region of Lake Superior are analogous to the concept of marine protected areas. These refuges, established specifically for lake trout (Salvelinus namaycush) and closed to most forms of recreational and commercial fishing, were implicated as one of several management actions leading to successful rehabilitation of Lake Superior lake trout. To investigate the potential significance of Gull Island Shoal and Devils Island Shoal refuges for populations of not only lake trout but also other fish species, relative abundances of lake trout, lake whitefish (Coregonus clupeaformis), and cisco (Coregonus artedi) were compared between areas sampled inside versus outside of refuge boundaries. During 1982–2010, lake trout relative abundance was higher and increased faster inside the refuges, where lake trout fishing was prohibited, than outside the refuges. Over the same period, lake whitefish relative abundance increased faster inside than outside the refuges. Both evaluations provided clear evidence that refuges protected these species. In contrast, trends in relative abundance of cisco, a prey item of lake trout, did not differ significantly between areas inside and outside the refuges. This result did not suggest indirect or cascading refuge effects due to changes in predator levels. Overall, this study highlights the potential of species-specific refuges to benefit other fish species beyond those that were the refuges' original target. Improved understanding of refuge effects on multiple species of Great Lakes fishes can be valuable for developing rationales for refuge establishment and predicting associated fish community-level effects.

Otimização conjunta de gráficos de X-barra - S ou X-barra - R: um procedimento de fácil implementação Joint optimization of X-bar - S or X-bar - R charts: an easily implemented procedure

Directory of Open Access Journals (Sweden)

Eugenio K. Epprecht

2007-12-01

Full Text Available Este trabalho desenvolve um modelo para escolha ótima dos parâmetros de operação de gráficos de X-barra e R (ou de X-barra e S que minimiza a razão entre o custo de amostragem e a rapidez de detecção de desvios na média ou aumentos na dispersão do processo. Admitem-se três formas alternativas para o problema: minimizar os tempos médios de sinalização sob uma restrição ao custo de amostragem; minimizar esse custo sob uma restrição aos tempos de sinalização; e o problema multiobjetivo de minimizar o custo e os tempos de sinalização. Restrições adicionais são permitidas, para tratar de variantes do problema encontráveis na prática. O procedimento evita a complexidade dos modelos de projeto econômico usuais. São detalhados métodos para determinação dos poucos parâmetros de especificação e entrada exigidos pelo modelo. Um exemplo mostra que o procedimento é de fácil aplicação. Tudo isto aumenta sua aplicabilidade para um grande espectro de situações práticas típicas.A model is developed for optimum choice of the operation parameters for X-bar - R (or X-bar - S charts, which minimizes the ratio of sampling costs to detection speed of shifts in the process mean or increases in the process dispersion. Three alternative problem formulations are allowed: minimization of the average time to signal subject to a sampling cost constraint; minimization of the sampling cost subject to a constraint on the average times to signal; and multi-objective optimization of both the average time to signal and the sampling cost. Through optional additional constraints, several practical variants of the problem are admitted. The procedure avoids the complexity of usual economic design models, and methods for determining the values for the few input and specification parameters required are given in detail. An example shows that the procedure is easy to apply. All these features increase its applicability for a wide range of

Avaliação fotoelástica de tensões transmitidas por próteses protocolos com barras confeccionadas em diferentes materiais e técnicas

OpenAIRE

Danilo Zaparolli

2014-01-01

Com o avanço da implantodontia e da estética, novos materiais estão sendo utilizados para substituir partes metálicas de próteses. Este estudo teve como objetivo comparar as tensões geradas por próteses implantossuportadas totais de mandíbula em função da variação do material utilizado nas barras e do modo de confecção, através de análise fotoelástica qualitativa. Em um modelo mestre simulando a curvatura da mandíbula foram posicionados 4 implantes de conexão locking taper. A partir deste pla...

Hazards of volcanic lakes: analysis of Lakes Quilotoa and Cuicocha, Ecuador

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G. Gunkel

2008-01-01

Full Text Available Volcanic lakes within calderas should be viewed as high-risk systems, and an intensive lake monitoring must be carried out to evaluate the hazard of potential limnic or phreatic-magmatic eruptions. In Ecuador, two caldera lakes – Lakes Quilotoa and Cuicocha, located in the high Andean region >3000 a.s.l. – have been the focus of these investigations. Both volcanoes are geologically young or historically active, and have formed large and deep calderas with lakes of 2 to 3 km in diameter, and 248 and 148 m in depth, respectively. In both lakes, visible gas emissions of CO₂ occur, and an accumulation of CO₂ in the deep water body must be taken into account.

Investigations were carried out to evaluate the hazards of these volcanic lakes, and in Lake Cuicocha intensive monitoring was carried out for the evaluation of possible renewed volcanic activities. At Lake Quilotoa, a limnic eruption and diffuse CO₂ degassing at the lake surface are to be expected, while at Lake Cuicocha, an increased risk of a phreatic-magmatic eruption exists.

Caracterização de Staphylococcus aureus isolados da barra de mão de carrinhos e alças de cestas de supermercados

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Daiane Buzzatto Oliveira

2016-07-01

Full Text Available Staphylococcus aureus é um dos agentes patogênicos mais notórios, sendo responsável por 45% das toxinfecções em todo o mundo. Um dos grandes problemas atuais é o desenvolvimento de cepas resistentes a antibióticos. Considerando a importância da disseminação desses micro-organismos na comunidade, o presente trabalho teve por objetivo determinar a presença de Staphylococcus aureus na barra de mão dos carrinhos e alças de cestas de supermercados da cidade de Campo Mourão - PR, e caracterizar a susceptibilidade dos isolados à oxacilina. Foram analisadas 120 amostras, sendo 60 coletadas das barras de mão de carrinhos e 60 coletadas das alças de cestas. Esse micro-organismo foi isolado em 75 amostras (62,5%, sendo que, desse total, 35 amostras (46,7% foram isoladas de carrinhos e 40 (53,3% de cestas de compras. As amostras positivas para Staphylococcus aureus foram submetidas aos testes de susceptibilidade, pelo método de disco-difusão, à oxacilina (cefoxitina e todas as amostras foram consideradas sensíveis a essa droga. Constatou que as barras de mãos e as alças de cestas de supermercados, podem ser consideradas como fômites, na disseminação de Staphylococcus aureus, sendo de extrema importância a higienização desses objetos, a fim de diminuir os riscos de contaminação na comunidade.Palavras-chave: Staphylococcus aureus. Contaminação. Superfícies. Oxacilina. ABSTRACTCharacterization of Staphylococcus aureus Isolated of shopping carts hand bars and handles of handheld shopping baskets in supermarketsStaphylococcus aureus is one of the most notorious pathogens, accounting for 45% of intoxications worldwide. One of the major problems today is the development of antibiotic-resistant strains. Considering the importance of dissemination of these micro- organisms in the community, this study aimed to determine the presence of Staphylococcus aureus in shopping carts hand bars and handles of handheld shopping baskets in

Relación entre el fenómeno de la ilusión de la mano falsa y variables personales

Directory of Open Access Journals (Sweden)

Gina Rodríguez-Melgarejo

2015-07-01

Full Text Available El fenómeno de la ilusión de la mano falsa (IMF se ha propuesto como un diseño que permite discriminar procesos perceptuales a partir de entradas sensoriales multimodales. Se han reportado varias modificaciones y variables que podrían afectar la generación del fenómeno. Este estudio se planteó bajo un diseño descriptivo-correlacional del fenómeno. Se realizó el procedimiento en jóvenes (16-48 años M = 20.86 años, DE = 4.4 colombianos para replicar el fenómeno de IMF. Los sujetos se dividieron al azar en dos grupos que diferían en el tipo de estimulación (sincrónica y desincronizada. La identificación de la IMF se realizó mediante la escala reportada en múltiples estudios, mostrando que en algunas variables como la estimulación se presentaba una diferencia en el reporte de IMF (P2. χ2 = 5.856: p < 0.05; P3. χ2 = 6.655: p < 0.01 y P7 (χ2 = 4.764: p < 0.05. Otras variables como sexo y dominancia manual mostraron algunas diferencias. La escala presenta una consistencia interna aceptable (α = 0.8. Los resultados de la IMF son similares a algunos estudios pero con puntuaciones menores que en los estudios iniciales, la diferencia en cuanto al género en tareas perceptuales podría explicar gran parte de los resultados.

Effects of white grubs on soil water infiltration.

Science.gov (United States)

Romero-López, A A; Rodríguez-Palacios, E; Alarcón-Gutiérrez, E; Geissert, D; Barois, I

2015-04-01

Water infiltration rates k were measured in mesocosms with soil and "white grubs" of Ancognatha falsa (Arrow) (Coleoptera: Melolonthidae). Three third instars of A. falsa and three adult earthworms Pontoscolex corethrurus were selected, weighted, and introduced into the mesocosms setting three treatments: soil + A. falsa, soil + P. corethrurus, and control (soil without any macroorganism). The experiment had a completely random design with four replicates per treatment (n = 4). The infiltration rates of soil matrix were assessed in each mesocosms with a minidisk tension infiltrometer. Six measurements were made along the experiment. Results showed that larvae of A. falsa promoted a higher water infiltration in the soil, compared to the control. On day 7, k values were similar among treatments, but k values after 28 days and up to 100 days were much higher in the A. falsa treatment (k = 0.00025 cm s(-1)) if compared to control (k = 0.00011 cm s(-1)) and P. corethrurus (k = 0.00008 cm s(-1)) treatments. The k values were significantly higher in the presence of larvae of A. falsa compared to the control and P. corethrurus treatments. The larvae of A. falsa are potential candidates for new assays on soil water infiltration with different tensions to evaluate the role of pores and holes created by the larvae on soils.

Principles of lake sedimentology

International Nuclear Information System (INIS)

Janasson, L.

1983-01-01

This book presents a comprehensive outline on the basic sedimentological principles for lakes, and focuses on environmental aspects and matters related to lake management and control-on lake ecology rather than lake geology. This is a guide for those who plan, perform and evaluate lake sedimentological investigations. Contents abridged: Lake types and sediment types. Sedimentation in lakes and water dynamics. Lake bottom dynamics. Sediment dynamics and sediment age. Sediments in aquatic pollution control programmes. Subject index

Lake Afdera: a threatened saline lake in Ethiopia | Getahun | SINET ...

African Journals Online (AJOL)

Lake Afdera is a saline lake located in the Afar region, Northern Ethiopia. Because of its inaccessibility it is one of the least studied lakes of the country. It supports life including three species of fish of which two are endemic. Recently, reports are coming out that this lake is used for salt extraction. This paper gives some ...

Water quality of Lake Austin and Town Lake, Austin, Texas

Science.gov (United States)

Andrews, Freeman L.; Wells, Frank C.; Shelby, Wanda J.; McPherson, Emma

1988-01-01

Lake Austin and Town Lake are located on the Colorado River in Travis County, central Texas, and serve as a source of water for municipal and industrial water supplies, electrical-power generation, and recreation for more than 500,000 people in the Austin metropolitan area. Lake Austin, located immediately downstream of Lake Travis, extends for more than 20 miles into the western edge of the city of Austin. Town Lake extends through the downtown area of the city of Austin for nearly 6 miles where the Colorado River is impounded by Longhorn Dam.

Refuge Lake Reclassification in 620 Minnesota Cisco Lakes under Future Climate Scenarios

Directory of Open Access Journals (Sweden)

Liping Jiang

2017-09-01

Full Text Available Cisco (Coregonus artedi is the most common coldwater stenothermal fish in Minnesota lakes. Water temperature (T and dissolved oxygen (DO in lakes are important controls of fish growth and reproduction and likely change with future climate warming. Built upon a previous study, this study uses a modified method to identify which of 620 cisco lakes in Minnesota can still support cisco populations under future climate and therefore be classified as cisco refuge lakes. The previous study used oxythermal stress parameter TDO3, the temperature at DO of 3 mg/L, simulated only from deep virtual lakes to classify 620 cisco lakes. Using four categories of virtual but representative cisco lakes in modified method, a one-dimensional water quality model MINLAKE2012 was used to simulate daily T and DO profiles in 82 virtual lakes under the past (1961–2008 and two future climate scenarios. A multiyear average of 31-day largest TDO3 over variable benchmark (VB periods, AvgATDO3VB, was calculated from simulated T and DO profiles using FishHabitat2013. Contour plots of AvgATDO3VB for four categories of virtual lakes were then developed to reclassify 620 cisco lakes into Tier 1 (AvgATDO3VB < 11 °C or Tier 2 refuge lakes, and Tier 3 non-refuge lakes (AvgATDO3VB > 17 °C. About 20% of 620 cisco lakes are projected to be refuge lakes under future climate scenarios, which is a more accurate projection (improving the prediction accuracy by ~6.5% from the previous study since AvgATDO3VB was found to vary by lake categories.

Coastal erosion hazard and vulnerability using sig tools. Comparison between "La Barra town, Buenaventura, (Pacific Ocean of Colombia) and Providence - Santa Catalina islands (Colombian Caribbean Sea)

Science.gov (United States)

Coca-Domínguez, Oswaldo; Ricaurte-Villota, Constanza; Morales-Giraldo, David; Rangel-Buitrago, Nelson

2014-05-01

Analysis of hazards and vulnerability associated to coastal erosion along coastlines is a first issue in order to establish plans for adaptation to climate change in coastal areas. La Barra Town, Buenaventura (Pacific ocean of Colombia) and Providence - Santa Catalina Islands (Colombian Caribbean) were selected to develop a detailed analysis of coastal erosion hazard and vulnerability from different perspectives: i) physical (hazard) , ii) social , iii) conservation approach and iv) cultural heritage (Raizal). The analysis was made by a semi quantitative approximation method, applying variables associated with the intrinsic coastal zone properties (i.e. type of beach, exposure of the coast to waves, etc.). Coastal erosion data and associated variables as well land use; conservation and heritage data were used to carry out a further detailed analysis of the human - structural vulnerability and exposure to hazards. The data shows erosion rates close to -17 m yr-1 in La Barra Town (highlighting their critical condition and urgent relocation process), while in some sectors of Providence Island, such as Old Town, erosion rate was -5 m yr-1. The observed erosion process affects directly the land use and the local and regional economy. The differences between indexes and the structural and physical vulnerability as well the use of methodological variables are presented in the context of each region. In this work, all the information was worked using a GIS environment since this allows editing and updating the information continuously. The application of this methodology generates useful information in order to promote risk management as well prevention, mitigation and reduction plans. In both areas the adaptation must be a priority strategy to be considered, including relocation alternatives and sustainable protection with the support of studies of uses and future outlooks in the coast. The methodology is framed into the use of GIS tools and it highlights their benefits

Watershed vs. within-lake drivers of nitrogen: phosphorus dynamics in shallow lakes.

Science.gov (United States)

Ginger, Luke J; Zimmer, Kyle D; Herwig, Brian R; Hanson, Mark A; Hobbs, William O; Small, Gaston E; Cotner, James B

2017-10-01

Research on lake eutrophication often identifies variables affecting amounts of phosphorus (P) and nitrogen (N) in lakes, but understanding factors influencing N:P ratios is important given its influence on species composition and toxin production by cyanobacteria. We sampled 80 shallow lakes in Minnesota (USA) for three years to assess effects of watershed size, proportion of watershed as both row crop and natural area, fish biomass, and lake alternative state (turbid vs. clear) on total N : total P (TN : TP), ammonium, total dissolved phosphorus (TDP), and seston stoichiometry. We also examined N:P stoichiometry in 20 additional lakes that shifted states during the study. Last, we assessed the importance of denitrification by measuring denitrification rates in sediment cores from a subset of 34 lakes, and by measuring seston δ 15 N in four additional experimental lakes before and after they were experimentally manipulated from turbid to clear states. Results showed alternative state had the largest influence on overall N:P stoichiometry in these systems, as it had the strongest relationship with TN : TP, seston C:N:P, ammonium, and TDP. Turbid lakes had higher N at given levels of P than clear lakes, with TN and ammonium 2-fold and 1.4-fold higher in turbid lakes, respectively. In lakes that shifted states, TN was 3-fold higher in turbid lakes, while TP was only 2-fold higher, supporting the notion N is more responsive to state shifts than is P. Seston δ 15 N increased after lakes shifted to clear states, suggesting higher denitrification rates may be important for reducing N levels in clear states, and potential denitrification rates in sediment cores were among the highest recorded in the literature. Overall, our results indicate lake state was a primary driver of N:P dynamics in shallow lakes, and lakes in clear states had much lower N at a given level of P relative to turbid lakes, likely due to higher denitrification rates. Shallow lakes are often

Changes in Rongbuk lake and Imja lake in the Everest region of Himalaya

Science.gov (United States)

Chen, W.; Doko, T.; Liu, C.; Ichinose, T.; Fukui, H.; Feng, Q.; Gou, P.

2014-12-01

The Himalaya holds the world record in terms of range and elevation. It is one of the most extensively glacierized regions in the world except the Polar Regions. The Himalaya is a region sensitive to climate change. Changes in the glacial regime are indicators of global climate changes. Since the second half of the last century, most Himalayan glaciers have melted due to climate change. These changes directly affected the changes of glacial lakes in the Himalayan region due to the glacier retreat. New glacial lakes are formed, and a number of them have expanded in the Everest region of the Himalayas. This paper focuses on the two glacial lakes which are Imja Lake, located at the southern slope, and Rongbuk Lake, located at the northern slope in the Mt. Everest region, Himalaya to present the spatio-temporal changes from 1976 to 2008. Topographical conditions between two lakes were different (Kruskal-Wallis test, p < 0.05). Rongbuk Lake was located at 623 m higher than Imja Lake, and radiation of Rongbuk Lake was higher than the Imja Lake. Although size of Imja Lake was larger than the Rongbuk Lake in 2008, the growth speed of Rongbuk Lake was accelerating since 2000 and exceeds Imja Lake in 2000-2008. This trend of expansion of Rongbuk Lake is anticipated to be continued in the 21st century. Rongbuk Lake would be the biggest potential risk of glacial lake outburst flood (GLOF) at the Everest region of Himalaya in the future.

Lake-wide distribution of Dreissena in Lake Michigan, 1999

Science.gov (United States)

Fleischer, Guy W.; DeSorcie, Timothy J.; Holuszko, Jeffrey D.

2001-01-01

The Great Lakes Science Center has conducted lake-wide bottom trawl surveys of the fish community in Lake Michigan each fall since 1973. These systematic surveys are performed at depths of 9 to 110 m at each of seven index sites around Lake Michigan. Zebra mussel (Dreissena polymorpha) populations have expanded to all survey locations and at a level to sufficiently contribute to the bottom trawl catches. The quagga (Dreissena bugensis), recently reported in Lake Michigan, was likely in the catches though not recognized. Dreissena spp. biomass ranged from about 0.6 to 15 kg/ha at the various sites in 1999. Dreissenid mussels were found at depths of 9 to 82 m, with their peak biomass at 27 to 46 m. The colonization of these exotic mussels has ecological implications as well as potential ramifications on the ability to sample fish consistently and effectively with bottom trawls in Lake Michigan.

Plantas aquáticas e nível de infestação das espécies presentes no reservatório de Barra Bonita, no rio Tietê

OpenAIRE

Carvalho,F.T.; Galo,M.L.B.T.; Velini,E.D.; Martins,D.

2003-01-01

O monitoramento da vegetação aquática permite avaliar a evolução das comunidades e determinar o potencial de danos associados a essas populações. O objetivo do trabalho foi identificar as plantas aquáticas e os níveis de infestação de cada espécie, presentes no reservatório de Barra Bonita. Foram avaliados todos os focos de vegetação aquática presentes na represa (335 pontos), sendo os pontos demarcados com um aparelho de GPS. As plantas foram identificadas e foi feita uma estimativa visual d...

Large Lakes Dominate CO2 Evasion From Lakes in an Arctic Catchment

Science.gov (United States)

Rocher-Ros, Gerard; Giesler, Reiner; Lundin, Erik; Salimi, Shokoufeh; Jonsson, Anders; Karlsson, Jan

2017-12-01

CO2 evasion from freshwater lakes is an important component of the carbon cycle. However, the relative contribution from different lake sizes may vary, since several parameters underlying CO2 flux are size dependent. Here we estimated the annual lake CO2 evasion from a catchment in northern Sweden encompassing about 30,000 differently sized lakes. We show that areal CO2 fluxes decreased rapidly with lake size, but this was counteracted by the greater overall coverage of larger lakes. As a result, total efflux increased with lake size and the single largest lake in the catchment dominated the CO2 evasion (53% of all CO2 evaded). By contrast, the contribution from the smallest ponds (about 27,000) was minor (evasion at the landscape scale.

Lake Michigan lake trout PCB model forecast post audit

Science.gov (United States)

Scenario forecasts for total PCBs in Lake Michigan (LM) lake trout were conducted using the linked LM2-Toxics and LM Food Chain models, supported by a suite of additional LM models. Efforts were conducted under the Lake Michigan Mass Balance Study and the post audit represents th...

Using Satellite Imagery to Monitor the Major Lakes; Case Study Lake Hamun

Science.gov (United States)

Norouzi, H.; Islam, R.; Bah, A.; AghaKouchak, A.

2015-12-01

Proper lakes function can ease the impact of floods and drought especially in arid and semi-arid regions. They are important environmentally and can directly affect human lives. Better understanding of the effect of climate change and human-driven changes on lakes would provide invaluable information for policy-makers and local people. As part of a comprehensive study, we aim to monitor the land-cover/ land-use changes in the world's major lakes using satellite observations. As a case study, Hamun Lake which is a pluvial Lake, also known as shallow Lake, located on the south-east of Iran and adjacent to Afghanistan, and Pakistan borders is investigated. The Lake is the main source of resources (agriculture, fishing and hunting) for the people around it and politically important in the region since it is shared among three different countries. The purpose of the research is to find the Lake's area from 1972 to 2015 and to see if any drought or water resources management has affected the lake. Analyzing satellites imagery from Landsat shows that the area of the Lake changes seasonally and intra-annually. Significant seasonal effects are found in 1975,1977, 1987, 1993, 1996, 1998, 2000, 2009 and 2011, as well as, substantial amount of shallow water is found throughout the years. The precipitation records as well as drought historical records are studied for the lake's basin. Meteorological studies suggest that the drought, decrease of rainfalls in the province and the improper management of the Lake have caused environmental, economic and geographical consequences. The results reveal that lake has experienced at least two prolong dryings since 1972 which drought cannot solely be blamed as main forcing factor.Proper lakes function can ease the impact of floods and drought especially in arid and semi-arid regions. They are important environmentally and can directly affect human lives. Better understanding of the effect of climate change and human-driven changes on lakes

Spatial distribution of seepage at a flow-through lake: Lake Hampen, Western Denmark

DEFF Research Database (Denmark)

Kidmose, Jacob Baarstrøm; Engesgaard, Peter Knudegaard; Nilsson, Bertel

2011-01-01

recharge patiern of the lake and relating these to the geologic history of the lake. Recharge of the surrounding aquifer by lake water occurs off shore in a narrow zone, as measured from lake–groundwater gradients. A 33-m-deep d18O profi le at the recharge side shows a lake d18O plume at depths...... that corroborates the interpretation of lake water recharging off shore and moving down gradient. Inclusion of lake bed heterogeneity in the model improved the comparison of simulated and observed discharge to the lake. The apparent age of the discharging groundwater to the lake was determined by CFCs, resulting...

Analysis of sandflies (Diptera: Psychodidae) in Barra do Garças, State of Mato Grosso, Brazil, and the influence of environmental variables on the vector density of Lutzomyia longipalpis (Lutz & Neiva, 1912).

Science.gov (United States)

Queiroz, Mirian Francisca Martins; Varjão, Jane Ramos; Moraes, Sinara Cristina de; Salcedo, Gladys Elena

2012-06-01

Leishmaniasis is an infectious and parasitic zoonotic, non-contagious, vector-borne disease caused by protozoa of the genus Leishmania. In Brazil, the major vector of Leishmania (Leishmania) infantum chagasi (Cunha & Chagas, 1934) is Lutzomyia longipalpis. Barra do Garças, State of Mato Grosso, was designated as a priority area by the Brazilian Ministry of Health for american visceral leishmaniasis, and it is important to identify the vector species present in this municipality. Our objective was to raise sandflies and study the influence of environmental variables on the vector density of Lutzomyia longipalpis. We performed entomological monitoring in 3 districts using Centers for Disease Control and Prevention (CDC) light traps and recorded human cases of american visceral leishmaniasis in the city. We calculated the relative frequency and richness of sandflies and applied a transfer function model to the vector density correlate with relative humidity. The sandfly population was composed of 2 genera and 27 species, totaling 8,097 individuals. Monitoring identified Lutzomyia longipalpis (44%), followed by Lutzomyia lenti (18.9%), Lutzomyia whitmani (13.9%), Lutzomyia carmelinoi (9.1%), Lutzomyia evandroi (5.1%), Lutzomyia termitophila (3.3%), Lutzomyia sordellii (1.9%), and 20 other species (Lutzomyia longipalpis showed occurrence peaks during the rainy season; there was a temporal correlation with humidity, but not with frequency or temperature. The presence of Lutzomyia longipalpis in the urban area of Barra do Garças underscores the changing disease profile, which was previously restricted to the wild environment.

Nutrient budgets (C, N and P and trophic dynamicsof a Brazilian tropical estuary: Barra das Jangadas

Directory of Open Access Journals (Sweden)

Carlos E. D Noriega

2011-06-01

Full Text Available This paper focuses on the nutrient dynamics of a tropical estuary on the northeastern Brazilian coast, studied using the LOICZ biogeochemical budgeting protocol. We describe the methodology and assumptions underlying this model. Input data (monthly for rainfall, evaporation, river discharge, and concentrations of salt, phosphorus and nitrogen were obtained during field campaigns in the Barra das Jangadas Estuary (BJE over a 5 years period (1999 to 2003. Mass balance results indicate large inputs of nutrients to the system. The model shows that the seasonal variation of the Net Ecosystem Metabolism (NEM indicates that the system passes from a stage of organic matter liquid production and mineralization during the dry season (-0.5 mmoles C m-2 d-1 to liquid mineralization during the rainy season (-19 mmoles C m-2 d-1. We suggest that the system varies slightly between autotrophy and heterotrophy during the year due to the rainfall regime, human activities in the basin (density population and sugarcane plantations, and associated DIP riverine loads. High per capita loads of N and P indicate a high population density and high runoff. The application of flux balance modeling was useful to understand the nutrient dynamics of this typical small tropical estuaryEste trabalho se focalizou na dinâmica de nutrientes de um estuário tropical na costa nordeste brasileira, usando o protocolo LOICZ de balanços biogeoquímicos. Nós descrevemos a metodologia e os pressupostos subjacentes a este modelo. Os dados de entrada (precipitação e evaporação mensal, vazão do rio, e as concentrações de sal, fósforo e nitrogênio foram obtidos durante as campanhas de campo no estuário de Barra das Jangadas - Brasil durante um período de 5 anos (1999 a 2003. Os resultados indicam grandes entradas de nutrientes ao sistema. O modelo mostrou que a variação sazonal do Metabolismo do Ecosistema (NEM indica que o sistema passa de uma fase de produção de l

Aquatic macrophyte richness in Danish lakes in relation to alkalinity, transparency, and lake area

DEFF Research Database (Denmark)

Vestergaard, Ole Skafte; Sand-Jensen, Kaj

2000-01-01

We examined the relationship between environmental factors and the richness of submerged macrophytes species in 73 Danish lakes, which are mainly small, shallow, and have mesotrophic to hypertrophic conditions. We found that mean species richness per lake was only 4.5 in acid lakes of low...... alkalinity but 12.3 in lakes of high alkalinity due to a greater occurrence of the species-rich group of elodeids. Mean species richness per lake also increased significantly with increasing Secchi depth. No significant relationship between species richness and lake surface area was observed among the entire...... group of lakes or a subset of eutrophic lakes, as the growth of submerged macrophytes in large lakes may be restricted by wave action in shallow water and light restriction in deep water. In contrast, macrophyte species richness increased with lake surface area in transparent lakes, presumably due...

LakeMIP Kivu: evaluating the representation of a large, deep tropical lake by a set of one-dimensional lake models

Directory of Open Access Journals (Sweden)

WIM Thiery

2014-02-01

Full Text Available The African great lakes are of utmost importance for the local economy (fishing, as well as being essential to the survival of the local people. During the past decades, these lakes experienced fast changes in ecosystem structure and functioning, and their future evolution is a major concern. In this study, for the first time a set of one-dimensional lake models are evaluated for Lake Kivu (2.28°S; 28.98°E, East Africa. The unique limnology of this meromictic lake, with the importance of salinity and subsurface springs in a tropical high-altitude climate, presents a worthy challenge to the seven models involved in the Lake Model Intercomparison Project (LakeMIP. Meteorological observations from two automatic weather stations are used to drive the models, whereas a unique dataset, containing over 150 temperature profiles recorded since 2002, is used to assess the model's performance. Simulations are performed over the freshwater layer only (60 m and over the average lake depth (240 m, since salinity increases with depth below 60 m in Lake Kivu and some lake models do not account for the influence of salinity upon lake stratification. All models are able to reproduce the mixing seasonality in Lake Kivu, as well as the magnitude and seasonal cycle of the lake enthalpy change. Differences between the models can be ascribed to variations in the treatment of the radiative forcing and the computation of the turbulent heat fluxes. Fluctuations in wind velocity and solar radiation explain inter-annual variability of observed water column temperatures. The good agreement between the deep simulations and the observed meromictic stratification also shows that a subset of models is able to account for the salinity- and geothermal-induced effects upon deep-water stratification. Finally, based on the strengths and weaknesses discerned in this study, an informed choice of a one-dimensional lake model for a given research purpose becomes possible.

Characterization of food bars manufactured with agroindustrial by-products and waste Caracterização de barras alimentícias elaboradas com subprodutos e resíduos agroindustriais

Directory of Open Access Journals (Sweden)

Andréa Paolucci Paiva

2012-06-01

Full Text Available Food bars are products obtained from the union of a number of components, standing out in the snack category due to their portability attribute with a focus on convenience and health. Utilization of by-products and agroindustrial food waste as ingredients in the making of food bars is highly important due to the utilization of leftovers of marked nutritional and functional value and decrease of the production cost. This work intended to evaluate the chemical and physicochemical aspects of food bars made with the by-products broken rice (BR and pequi nut (PN, soybean extract residue (SER, and pineapple waste (PW. Distinct proportions of BR: SER respectively were used, amounting to five treatments: 1:0 (A; 3:1 (B; 1:1 (C; 1:3 (D and 0:1(E and fixed amounts of the other components. For the statistical analysis, variance analysis and the Tukey test were performed to 5% significance. The moisture, protein, lipid, ash, mineral, and dietary fiber contents were directly increased as the SER was increased and the amount of BR was decreased. However, the opposite was found with both carbohydrates and calories. The soluble solids, pH and water activity values presented increases with the increased soybean extract residue. All the treatments presented slightly acidic pH and water activity bellow 0.6, favoring microbiological safety. In the chemical score, treatment A presented lysine as the limiting aminoacid in relation to the Food and Agriculture Organization - FAO/WHO reference (1990. The food bars can be considered rich in dietary fiber and with considerable nutritional support. Treatments D and E proved better in the set of the variables studied for human consumption.Barras alimentícias são produtos obtidos a partir da junção de vários componentes, destacando-se na categoria dos snacks em razão do atributo portabilidade com foco em conveniência e saúde. A utilização de subprodutos e de resíduos agroindustriais alimentícios como ingredientes

Methane emissions from permafrost thaw lakes limited by lake drainage.

NARCIS (Netherlands)

van Huissteden, J.; Berrittella, C.; Parmentier, F.J.W.; Mi, Y.; Maximov, T.C.; Dolman, A.J.

2011-01-01

Thaw lakes in permafrost areas are sources of the strong greenhouse gas methane. They develop mostly in sedimentary lowlands with permafrost and a high excess ground ice volume, resulting in large areas covered with lakes and drained thaw-lake basins (DTLBs; refs,). Their expansion is enhanced by

Great Lakes Bathymetry

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry of Lakes Michigan, Erie, Saint Clair, Ontario and Huron has been compiled as a component of a NOAA project to rescue Great Lakes lake floor geological and...

Lake and lake-related drainage area parameters for site investigation program

Energy Technology Data Exchange (ETDEWEB)

Blomqvist, P.; Brunberg, A.K. [Uppsala Univ. (Sweden). Dept. of Limnology; Brydsten, L [Umeaa Univ. (Sweden). Dept. of Ecology and Environmental Science

2000-09-01

In this paper, a number of parameters of importance to a preliminary determination of the ecological function of lakes are presented. The choice of parameters have been made with respect to a model for the determination of the nature conservation values of lakes which is currently being developed by the authors of this report, but is also well suited for a general description of the lake type and the functioning of the inherent ecosystem. The parameters have been divided into five groups: (1) The location of the object relative important gradients in the surrounding nature; (2) The lake catchment area and its major constituents; (3) The lake morphometry; (4) The lake ecosystem; (5) Human-induced damages to the lake ecosystem. The first two groups, principally based on the climate, hydrology, geology and vegetation of the catchment area represent parameters that can be used to establish the rarity and representativity of the lake, and will in the context of site investigation program be used as a basis for generalisation of the results. The third group, the lake morphometry parameters, are standard parameters for the outline of sampling programmes and for calculations of the physical extension of different key habitats in the system. The fourth group, the ecosystem of the lake, includes physical, chemical and biological parameters required for determination of the stratification pattern, light climate, influence from the terrestrial ecosystem of the catchment area, trophic status, distribution of key habitats, and presence of fish and rare fauna and flora in the lake. In the context of site investigation program, the parameters in these two groups will be used for budget calculations of the flow of energy and material in the system. The fifth group, finally, describes the degree on anthropogenic influence on the ecosystem and will in the context of site investigation programmes be used to judge eventual malfunctioning within the entire, or parts of, the lake

Lake and lake-related drainage area parameters for site investigation program

International Nuclear Information System (INIS)

Blomqvist, P.; Brunberg, A.K.; Brydsten, L

2000-09-01

In this paper, a number of parameters of importance to a preliminary determination of the ecological function of lakes are presented. The choice of parameters have been made with respect to a model for the determination of the nature conservation values of lakes which is currently being developed by the authors of this report, but is also well suited for a general description of the lake type and the functioning of the inherent ecosystem. The parameters have been divided into five groups: 1) The location of the object relative important gradients in the surrounding nature; 2) The lake catchment area and its major constituents; 3) The lake morphometry; 4) The lake ecosystem; 5) Human-induced damages to the lake ecosystem. The first two groups, principally based on the climate, hydrology, geology and vegetation of the catchment area represent parameters that can be used to establish the rarity and representativity of the lake, and will in the context of site investigation program be used as a basis for generalisation of the results. The third group, the lake morphometry parameters, are standard parameters for the outline of sampling programmes and for calculations of the physical extension of different key habitats in the system. The fourth group, the ecosystem of the lake, includes physical, chemical and biological parameters required for determination of the stratification pattern, light climate, influence from the terrestrial ecosystem of the catchment area, trophic status, distribution of key habitats, and presence of fish and rare fauna and flora in the lake. In the context of site investigation program, the parameters in these two groups will be used for budget calculations of the flow of energy and material in the system. The fifth group, finally, describes the degree on anthropogenic influence on the ecosystem and will in the context of site investigation programmes be used to judge eventual malfunctioning within the entire, or parts of, the lake ecosystem

Rubidium-strontium ages from the Oxford Lake-Knee Lake greenstone belt, northern Manitoba

International Nuclear Information System (INIS)

Clark, G.S.; Cheung, S.-P.

1980-01-01

Rb-Sr whole-rock ages have been determined for rocks from the Oxford Lake-Knee Lake-Gods Lake geenstone belt in the Superior Province of northeastern Manitoba. The age of the Magill Lake Pluton is 2455 +- 35 Ma(lambda 87 Rb = 1.42 x 10 -11 yr -1 ), with an initial 87 Sr/ 86 Sr ratio of 0.7078 +- 0.0043. This granite stock intrudes the Oxford Lake Group, so it is post-tectonic and probably related to the second, weaker stage of metamorphism. The age of the Bayly Lake Pluton is 2424 +- 74 Ma, with an initial 87 Sr/ 86 Sr ratio of 0.7029 +- 0.0001. This granodioritic batholith complex does not intrude the Oxford Lake Group. It is syn-tectonic and metamorphosed. The age of volcanic rocks of the Hayes River Group, from Goose Lake (30 km south of Gods Lake Narrows), is 2680 +- 125 Ma, with an initial 87 Sr/ 86 Sr ratio of 0.7014 +- 0.0009. The age for the Magill Lake and Bayly Lake Plutons can be interpreted as the minimum ages of granite intrusion in the area. The age for the Hayes River Group volcanic rocks is consistent with Rb-Sr ages of volcanic rocks from other Archean greenstone belts within the northwestern Superior Province. (auth)

A Dynamical Downscaling study over the Great Lakes Region Using WRF-Lake: Historical Simulation

Science.gov (United States)

Xiao, C.; Lofgren, B. M.

2014-12-01

As the largest group of fresh water bodies on Earth, the Laurentian Great Lakes have significant influence on local and regional weather and climate through their unique physical features compared with the surrounding land. Due to the limited spatial resolution and computational efficiency of general circulation models (GCMs), the Great Lakes are geometrically ignored or idealized into several grid cells in GCMs. Thus, the nested regional climate modeling (RCM) technique, known as dynamical downscaling, serves as a feasible solution to fill the gap. The latest Weather Research and Forecasting model (WRF) is employed to dynamically downscale the historical simulation produced by the Geophysical Fluid Dynamics Laboratory-Coupled Model (GFDL-CM3) from 1970-2005. An updated lake scheme originated from the Community Land Model is implemented in the latest WRF version 3.6. It is a one-dimensional mass and energy balance scheme with 20-25 model layers, including up to 5 snow layers on the lake ice, 10 water layers, and 10 soil layers on the lake bottom. The lake scheme is used with actual lake points and lake depth. The preliminary results show that WRF-Lake model, with a fine horizontal resolution and realistic lake representation, provides significantly improved hydroclimates, in terms of lake surface temperature, annual cycle of precipitation, ice content, and lake-effect snowfall. Those improvements suggest that better resolution of the lakes and the mesoscale process of lake-atmosphere interaction are crucial to understanding the climate and climate change in the Great Lakes region.

[Characterizing chromophoric dissolved organic matter (CDOM) in Lake Honghu, Lake Donghu and Lake Liangzihu using excitation-emission matrices (EEMs) fluorescence and parallel factor analysis (PARAFAC)].

Science.gov (United States)

Zhou, Yong-Qiang; Zhang, Yun-Lin; Niu, Cheng; Wang, Ming-Zhu

2013-12-01

Little is known about DOM characteristics in medium to large sized lakes located in the middle and lower reaches of Yangtze River, like Lake Honghu, Lake Donghu and Lake Liangzihu. Absorption, fluorescence and composition characteristics of chromophoric dissolved organic matter (CDOM) are presented using the absorption spectroscopy, the excitation-emission ma trices (EEMs) fluorescence and parallel factor analysis (PARAFAC) model based on the data collected in Sep-Oct. 2007 including 15, 9 and 10 samplings in Lake Honghu, Lake Donghu and Lake Liangzihu, respectively. CDOM absorption coefficient at 350 nm a(350) coefficient in Lake Honghu was significantly higher than those in Lake Donghu and Lake Liangzihu (t-test, pCDOM spectral slope in the wavelength range of 280-500 nm (S280-500) and a(350) (R2 =0. 781, p<0. 001). The mean value of S280-500 in Lake Honghu was significantly lower than those in Lake Donghu (t-test, pLake Liangzihu (t-test, p<0. 001). The mean value of spectral slope ratio SR in Lake Honghu was also significantly lower than those in Lake Donghu and Lake Liangzihu (t-test, p<0. 05). Two humic-like (C1, C2) and two protein-like fluorescent components (C3, C4) were identified by PARAFAC model, among which significant positive correlations were found between C1 and C2 (R2 =0. 884, p<0. 001), C3 and C4 (R2 =0. 677, p<0.001), respectively, suggesting that the sources of the two humic-like components as well as the two protein-like components were similar. However, no significant correlation has been found between those 4 fluorescent components and DOC concentration. Th e fluorescenceindices of FI255 (HIX), Fl265, FI310 (BIX) and Fl370 in Lake Donghu were all significantly higher than those in Lake Liangzihu (t-test, p <0.05) and Lake Honghu (t-test, p<0. 01), indicating that the eutrophication status in Lake Donghu was higher than Lake Honghu and Lake Liangzihu.

Control Rods in high-Flux Swimming-Pool Reactors; Les Barres de Controle dans les Piles Piscines a Haut Flux; Reguliruyushchie sterzhni dlya reaktorov bassejnovogo tipa s vysokoj plotnost'yu nejtronnogo potoka; Las Barras de Control en los Reactores Tipo Piscina de Flujo Elevado

Energy Technology Data Exchange (ETDEWEB)

Ageroni, P.; Blum, P.; Denielou, G.; Denis, P.; Meunier, C. [Centre d' Etudes Nucleaires de Grenoble (France)

1964-06-15

etudes en cours sur les barres de controle des piles piscine a coeur ouvert fonctionnant dans la bande de 10 a 30 MW. (author) [Spanish] La memoria examina los problemas planteados por las barras de control en los reactores de investigacion de tipo piscina abierta, de alta potencia especifica y elevado flujo, basandose en calculos y experimentos efectuados durante la construccion del reactor SILOE. Expone asimismo la experiencia adquirida con las barras de control mientras el reactor funcionaba a 13 MW. Examina sucesivamente: a) Los balances de reactividad y los valores de esta para los diversos tipos de barras de control que se han ensayado (cadmio, B4C, tierras raras, y combinaciones de estas sustancias); b) los picos de flujo que la presencia de barras de control crea en el cuerpo del reactor, su influencia sobre la potencia especifica, los flujos rapidos que se pueden obtener y los medios para incrementarlos; c) los problemas tecnologicos planteados por la construccion de las barras; d) los problemas de refrigeracion, vibracion, deformacion y tiempo necesario para introducirlos en el reactor. Para terminar, describe someramente loe estudios que se estan realizando con las barras de control de reactores de tipo piscina de cuerpo abierto cuando funcionan en el intervalo de potencias comprendido entre 10 y 30 MW. (author) [Russian] 1. V svete raschetov i jeksperimentov, provedennyh pri postrojke reaktora STLOE , rassmatrivajutsja problemy, voznikajushhie v svjazi s regulirujushhimi sterzhnjami dlja issledovatel'skih reaktorov otkrytogo bassejnovogo tipa s bol'shoj udel'noj moshhnost'ju i s vysokoj plotnost'ju nejtronnogo potoka. Privodjatsja takzhe rezul'taty ispytanija jetogo reaktora pri .moshhnosti 13 mgvt v svjazi s razlichnymi regulirujushhimi sterzhnjami. 2. Posledov atel'no rassmatrivajutsja sledujushhie problemy: a) balans reaktivnosti i reaktivnaja sposobnost' podvergnutyh ispytanijam regulirujushhih sterzhnej razlichnyh tipov (kadmij, B{sub 4}C , redkie zemli

Deglaciation, lake levels, and meltwater discharge in the Lake Michigan basin

Science.gov (United States)

Colman, Steven M.; Clark, J.A.; Clayton, L.; Hansel, A.K.; Larsen, C.E.

1994-01-01

The deglacial history of the Lake Michigan basin, including discharge and routing of meltwater, is complex because of the interaction among (1) glacial retreats and re-advances in the basin (2) the timing of occupation and the isostatic adjustment of lake outlets and (3) the depositional and erosional processes that left evidence of past lake levels. In the southern part of the basin, a restricted area little affected by differential isostasy, new studies of onshore and offshore areas allow refinement of a lake-level history that has evolved over 100 years. Important new data include the recognition of two periods of influx of meltwater from Lake Agassiz into the basin and details of the highstands gleaned from sedimentological evidence. Major disagreements still persist concerning the exact timing and lake-level changes associated with the Algonquin phase, approximately 11,000 BP. A wide variety of independent data suggests that the Lake Michigan Lobe was thin, unstable, and subject to rapid advances and retreats. Consequently, lake-level changes were commonly abrupt and stable shorelines were short-lived. The long-held beliefs that the southern part of the basin was stable and separated from deformed northern areas by a hinge-line discontinuity are becoming difficult to maintain. Numerical modeling of the ice-earth system and empirical modeling of shoreline deformation are both consistent with observed shoreline tilting in the north and with the amount and pattern of modern deformation shown by lake-level gauges. New studies of subaerial lacustrine features suggest the presence of deformed shorelines higher than those originally ascribed to the supposed horizontal Glenwood level. Finally, the Lake Michigan region as a whole appears to behave in a similar manner to other areas, both local (other Great Lakes) and regional (U.S. east coast), that have experienced major isostatic changes. Detailed sedimentological and dating studies of field sites and additional

Great Lakes

Science.gov (United States)

Edsall, Thomas A.; Mac, Michael J.; Opler, Paul A.; Puckett Haecker, Catherine E.; Doran, Peter D.

1998-01-01

The Great Lakes region, as defined here, includes the Great Lakes and their drainage basins in Minnesota, Wisconsin, Illinois, Indiana, Ohio, Pennsylvania, and New York. The region also includes the portions of Minnesota, Wisconsin, and the 21 northernmost counties of Illinois that lie in the Mississippi River drainage basin, outside the floodplain of the river. The region spans about 9º of latitude and 20º of longitude and lies roughly halfway between the equator and the North Pole in a lowland corridor that extends from the Gulf of Mexico to the Arctic Ocean.The Great Lakes are the most prominent natural feature of the region (Fig. 1). They have a combined surface area of about 245,000 square kilometers and are among the largest, deepest lakes in the world. They are the largest single aggregation of fresh water on the planet (excluding the polar ice caps) and are the only glacial feature on Earth visible from the surface of the moon (The Nature Conservancy 1994a).The Great Lakes moderate the region’s climate, which presently ranges from subarctic in the north to humid continental warm in the south (Fig. 2), reflecting the movement of major weather masses from the north and south (U.S. Department of the Interior 1970; Eichenlaub 1979). The lakes act as heat sinks in summer and heat sources in winter and are major reservoirs that help humidify much of the region. They also create local precipitation belts in areas where air masses are pushed across the lakes by prevailing winds, pick up moisture from the lake surface, and then drop that moisture over land on the other side of the lake. The mean annual frost-free period—a general measure of the growing-season length for plants and some cold-blooded animals—varies from 60 days at higher elevations in the north to 160 days in lakeshore areas in the south. The climate influences the general distribution of wild plants and animals in the region and also influences the activities and distribution of the human

Lakes, Lagerstaetten, and Evolution

Science.gov (United States)

Kordesch, E. G.; Park, L. E.

2001-12-01

The diversity of terrestrial systems is estimated to be greater than in the marine realm. However no hard data yet exists to substantiate this claim. Ancient lacustrine deposits may preserve an exceptionally diverse fossil fauna and aid in determining continental faunal diversities. Fossils preserved in lake deposits, especially those with exceptional preservation (i.e. Konservat Lagerstaetten), may represent a dependable method for determining species diversity changes in the terrestrial environment because of their faunal completeness. Important Konservat Lagerstaetten, such as the Green River Formation (US) and Messel (Germany), both Eocene in age, are found in lake sediments and show a remarkable faunal diversity for both vertebrates and invertebrates. To date information from nearly 25 lake lagerstaetten derived from different types of lake basins from the Carboniferous to the Miocene have been collected and described. Carboniferous sites derive from the cyclothems of Midcontinent of the US while many Cenozoic sites have been described from North and South America as well as Europe and Australia. Asian sites contain fossils from the Mesozoic and Cenozoic. With this data, insight into the evolutionary processes associated with lake systems can be examined. Do lakes act as unique evolutionary crucibles in contrast to marine systems? The speciation of cichlid fishes in present-day African lakes appears to be very high and is attributed to the diversity of environments found in large rift lakes. Is this true of all ancient lakes or just large rift lakes? The longevity of a lake system may be an important factor in allowing speciation and evolutionary processes to occur; marine systems are limited only in the existence of environments as controlled by tectonics and sea level changes, on the order of tens of millions of years. Rift lakes are normally the longest lived in the millions of years. Perhaps there are only certain types of lakes in which speciation of

Suspended-sediment budget, flow distribution, and lake circulation for the Fox Chain of Lakes in Lake and McHenry Counties, Illinois, 1997-99

Science.gov (United States)

Schrader, David L.; Holmes, Robert R.

2000-01-01

The Fox Chain of Lakes is a glacial lake system in McHenry and Lake Counties in northern Illinois and southern Wisconsin. Sedimentation and nutrient overloading have occurred in the lake system since the first dam was built (1907) in McHenry to raise water levels in the lake system. Using data collected from December 1, 1997, to June 1, 1999, suspended-sediment budgets were constructed for the most upstream lake in the system, Grass Lake, and for the lakes downstream from Grass Lake. A total of 64,900 tons of suspended sediment entered Grass Lake during the study, whereas a total of 70,600 tons of suspended sediment exited the lake, indicating a net scour of 5,700 tons of sediment. A total of 44,100 tons of suspended sediment was measured exiting the Fox Chain of Lakes at Johnsburg, whereas 85,600 tons entered the system downstream from Grass Lake. These suspended-sediment loads indicate a net deposition of 41,500 tons downstream from Grass Lake, which represents a trapping efficiency of 48.5 percent. A large amount of recreational boating takes place on the Fox Chain of Lakes during summer months, and suspended-sediment load was observed to rise from 110 tons per day to 339 tons per day during the 1999 Memorial Day weekend (May 26 ?31, 1999). Presumably, this rise was the result of the boating traffic because no other hydrologic event is known to have occurred that might have caused the rise. This study covers a relatively short period and may not represent the long-term processes of the Fox Chain of Lakes system, although the sediment transport was probably higher than an average year. The bed sediments found on the bottom of the lakes are composed of mainly fine particles in the silt-clay range. The Grass Lake sediments were characterized as black peat with an organic content of between 9 and 18 percent, and the median particle size ranged from 0.000811 to 0.0013976 inches. Other bed material samples were collected at streamflow-gaging stations on the

33 CFR 162.220 - Hoover Dam, Lake Mead, and Lake Mohave (Colorado River), Ariz.-Nev.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Hoover Dam, Lake Mead, and Lake... REGULATIONS § 162.220 Hoover Dam, Lake Mead, and Lake Mohave (Colorado River), Ariz.-Nev. (a) Lake Mead and... the axis of Hoover Dam and that portion of Lake Mohave (Colorado River) extending 4,500 feet...

First evidence of successful natural reproduction by planted lake trout in Lake Huron

Science.gov (United States)

Nester, Robert T.; Poe, Thomas P.

1984-01-01

Twenty-two lake trout (Salvelinus namaycush) swim-up fry, 24-27 mm long, were captured with emergent fry traps and a tow net in northwestern Lake Huron on a small nearshore reef off Alpena, Michigan, between May 10 and June 1, 1982. These catches represent the first evidence of successful production of swim-up fry by planted, hatchery-reared lake trout in Lake Huron since the lake trout rehabilitation program began in 1973.

SISTEMAS DE IDENTIFICACIÓN POR RADIOFRECUENCIA, CÓDIGO DE BARRAS Y SU RELACIÓN CON LA GESTIÓN DE LA CADENA DE SUMINISTRO

Directory of Open Access Journals (Sweden)

ALEXANDER CORREA ESPINAL

2010-01-01

Full Text Available El articulo muestra, a través del análisis de libros, artículos científicos y algunos estudios existentes, el estado del arte y la relación entre los sistemas e identificación (código de barras y radiofrecuencia y la gestión de la cadena de suministro, en aplicaciones significativas a nivel mundial y de Colombia. Para ello, se compilan conceptos generales de los sistemas de identificación presentando sus definiciones, componentes de hardware/software, aplicaciones en la cadena de suministro y el uso que grandes, medianas y pequeñas empresas le otorgan. El estudio pone en evidencia la importancia que estas tecnologías tienen para mejorar el desempeño y la trazabilidad, simplificar operaciones, reducir costos y agilizar los flujos de información en la cadena de suministro.

Estimation of lake water - groundwater interactions in meromictic mining lakes by modelling isotope signatures of lake water.

Science.gov (United States)

Seebach, Anne; Dietz, Severine; Lessmann, Dieter; Knoeller, Kay

2008-03-01

A method is presented to assess lake water-groundwater interactions by modelling isotope signatures of lake water using meteorological parameters and field data. The modelling of delta(18)O and deltaD variations offers information about the groundwater influx into a meromictic Lusatian mining lake. Therefore, a water balance model is combined with an isotope water balance model to estimate analogies between simulated and measured isotope signatures within the lake water body. The model is operated with different evaporation rates to predict delta(18)O and deltaD values in a lake that is only controlled by weather conditions with neither groundwater inflow nor outflow. Comparisons between modelled and measured isotope values show whether the lake is fed by the groundwater or not. Furthermore, our investigations show that an adaptation of the Craig and Gordon model [H. Craig, L.I. Gordon. Deuterium and oxygen-18 variations in the ocean and the marine atmosphere. In Stable Isotopes in Oceanographic Studies and Paleotemperature, Spoleto, E. Tongiorgi (Ed.), pp. 9-130, Consiglio Nazionale delle Ricerche, Laboratorio di Geologia Nucleare, Pisa (1965).] to specific conditions in temperate regions seems necessary.

Lake Sturgeon, Acipenser fulvescens, movements in Rainy Lake, Minnesota and Ontario

Science.gov (United States)

Adams, W.E.; Kallemeyn, L.W.; Willis, D.W.

2006-01-01

Rainy Lake, Minnesota-Ontario, contains a native population of Lake Sturgeon (Acipenser fulvescens) that has gone largely unstudied. The objective of this descriptive study was to summarize generalized Lake Sturgeon movement patterns through the use of biotelemetry. Telemetry data reinforced the high utilization of the Squirrel Falls geographic location by Lake Sturgeon, with 37% of the re-locations occurring in that area. Other spring aggregations occurred in areas associated with Kettle Falls, the Pipestone River, and the Rat River, which could indicate spawning activity. Movement of Lake Sturgeon between the Seine River and the South Arm of Rainy Lake indicates the likelihood of one integrated population on the east end of the South Arm. The lack of re-locations in the Seine River during the months of September and October may have been due to Lake Sturgeon moving into deeper water areas of the Seine River and out of the range of radio telemetry gear or simply moving back into the South Arm. Due to the movements between Minnesota and Ontario, coordination of management efforts among provincial, state, and federal agencies will be important.

Determining lake surface water temperatures worldwide using a tuned one-dimensional lake model (FLake, v1)

Science.gov (United States)

Layden, Aisling; MacCallum, Stuart N.; Merchant, Christopher J.

2016-06-01

A tuning method for FLake, a one-dimensional (1-D) freshwater lake model, is applied for the individual tuning of 244 globally distributed large lakes using observed lake surface water temperatures (LSWTs) derived from along-track scanning radiometers (ATSRs). The model, which was tuned using only three lake properties (lake depth, snow and ice albedo and light extinction coefficient), substantially improves the measured mean differences in various features of the LSWT annual cycle, including the LSWTs of saline and high altitude lakes, when compared to the observed LSWTs. Lakes whose lake-mean LSWT persists below 1 °C for part of the annual cycle are considered to be seasonally ice-covered. For trial seasonally ice-covered lakes (21 lakes), the daily mean and standard deviation (2σ) of absolute differences between the modelled and observed LSWTs are reduced from 3.07 °C ± 2.25 °C to 0.84 °C ± 0.51 °C by tuning the model. For all other trial lakes (14 non-ice-covered lakes), the improvement is from 3.55 °C ± 3.20 °C to 0.96 °C ± 0.63 °C. The post tuning results for the 35 trial lakes (21 seasonally ice-covered lakes and 14 non-ice-covered lakes) are highly representative of the post-tuning results of the 244 lakes. For the 21 seasonally ice-covered lakes, the modelled response of the summer LSWTs to changes in snow and ice albedo is found to be statistically related to lake depth and latitude, which together explain 0.50 (R2adj, p = 0.001) of the inter-lake variance in summer LSWTs. Lake depth alone explains 0.35 (p = 0.003) of the variance. Lake characteristic information (snow and ice albedo and light extinction coefficient) is not available for many lakes. The approach taken to tune the model, bypasses the need to acquire detailed lake characteristic values. Furthermore, the tuned values for lake depth, snow and ice albedo and light extinction coefficient for the 244 lakes provide some guidance on improving FLake LSWT modelling.

Geochemical monitoring of volcanic lakes. A generalized box model for active crater lakes

Directory of Open Access Journals (Sweden)

Franco Tassi

2011-06-01

Full Text Available

In the past, variations in the chemical contents (SO42−, Cl−, cations of crater lake water have not systematically demonstrated any relationships with eruptive activity. Intensive parameters (i.e., concentrations, temperature, pH, salinity should be converted into extensive parameters (i.e., fluxes, changes with time of mass and solutes, taking into account all the internal and external chemical–physical factors that affect the crater lake system. This study presents a generalized box model approach that can be useful for geochemical monitoring of active crater lakes, as highly dynamic natural systems. The mass budget of a lake is based on observations of physical variations over a certain period of time: lake volume (level, surface area, lake water temperature, meteorological precipitation, air humidity, wind velocity, input of spring water, and overflow of the lake. This first approach leads to quantification of the input and output fluxes that contribute to the actual crater lake volume. Estimating the input flux of the "volcanic" fluid (Qf- kg/s –– an unmeasurable subsurface parameter –– and tracing its variations with time is the major focus during crater lake monitoring. Through expanding the mass budget into an isotope and chemical budget of the lake, the box model helps to qualitatively characterize the fluids involved. The (calculated Cl− content and dD ratio of the rising "volcanic" fluid defines its origin. With reference to continuous monitoring of crater lakes, the present study provides tips that allow better calculation of Qf in the future. At present, this study offers the most comprehensive and up-to-date literature review on active crater lakes.

Water-quality and lake-stage data for Wisconsin lakes, water year 2014

Science.gov (United States)

Manteufel, S. Bridgett; Robertson, Dale M.

2017-05-25

IntroductionThe U.S. Geological Survey (USGS), in cooperation with local and other agencies, collects data at selected lakes throughout Wisconsin. These data, accumulated over many years, provide a database for developing an improved understanding of the water quality of lakes. To make these data available to interested parties outside the USGS, the data are published annually in this report series. The locations of water-quality and lake-stage stations in Wisconsin for water year 2014 are shown in figure 1. A water year is the 12-month period from October 1 through September 30. It is designated by the calendar year in which it ends. Thus, the periodOctober 1, 2013, through September 30, 2014, is called “water year 2014.”The purpose of this report is to provide information about the chemical and physical characteristics of Wisconsin lakes. Data that have been collected at specific lakes, and information to aid in the interpretation of those data, are included in this report. Data collected include measurements of in-lake water quality and lake stage. Time series of Secchi depths, surface total phosphorus, and chlorophyll a concentrations collected during nonfrozen periods are included for many lakes. Graphs of vertical profiles of temperature, dissolved oxygen, pH, and specific conductance are included for sites where these parameters were measured. Descriptive information for each lake includes the location of the lake, area of the lake’s watershed, period for which data are available, revisions to previously published records, and pertinent remarks. Additional data, such as streamflow and water quality in tributary and outlet streams of some of the lakes, are published online at http://nwis.waterdata.usgs.gov/wi/nwis.Water-resources data, including stage and discharge data at most streamflow-gaging stations, are available online. The Wisconsin Water Science Center’s home page is at https://www.usgs.gov/centers/wisconsin-water-science-center. Information

Lake Michigan lake trout PCB model forecast post audit (oral presentation)

Science.gov (United States)

Scenario forecasts for total PCBs in Lake Michigan (LM) lake trout were conducted using the linked LM2-Toxics and LM Food Chain models, supported by a suite of additional LM models. Efforts were conducted under the Lake Michigan Mass Balance Study and the post audit represents an...

Simulating Lake-Groundwater Interactions During Decadal Climate Cycles: Accounting For Variable Lake Area In The Watershed

Science.gov (United States)

Virdi, M. L.; Lee, T. M.

2009-12-01

The volume and extent of a lake within the topo-bathymetry of a watershed can change substantially during wetter and drier climate cycles, altering the interaction of the lake with the groundwater flow system. Lake Starr and other seepage lakes in the permeable sandhills of central Florida are vulnerable to climate changes as they rely exclusively on rainfall and groundwater for inflows in a setting where annual rainfall and recharge vary widely. The groundwater inflow typically arrives from a small catchment area bordering the lake. The sinkhole origin of these lakes combined with groundwater pumping from underlying aquifers further complicate groundwater interactions. Understanding the lake-groundwater interactions and their effects on lake stage over multi-decadal climate cycles is needed to manage groundwater pumping and public expectation about future lake levels. The interdependence between climate, recharge, changing lake area and the groundwater catchment pose unique challenges to simulating lake-groundwater interactions. During the 10-year study period, Lake Starr stage fluctuated more than 13 feet and the lake surface area receded and expanded from 96 acres to 148 acres over drier and wetter years that included hurricanes, two El Nino events and a La Nina event. The recently developed Unsaturated Zone Flow (UZF1) and Lake (LAK7) packages for MODFLOW-2005 were used to simulate the changing lake sizes and the extent of the groundwater catchment contributing flow to the lake. The lake area was discretized to occupy the largest surface area at the highest observed stage and then allowed to change size. Lake cells convert to land cells and receive infiltration as receding lake area exposes the underlying unsaturated zone to rainfall and recharge. The unique model conceptualization also made it possible to capture the dynamic size of the groundwater catchment contributing to lake inflows, as the surface area and volume of the lake changed during the study

Lake Granbury and Lake Whitney Assessment Initiative Final Scientific/Technical Report Summary

Energy Technology Data Exchange (ETDEWEB)

Harris, B. L. [Texas AgriLife Research, College Station, TX (United States); Roelke, Daniel [Texas AgriLife Research, College Station, TX (United States); Brooks, Bryan [Texas AgriLife Research, College Station, TX (United States); Grover, James [Texas AgriLife Research, College Station, TX (United States)

2010-10-11

A team of Texas AgriLife Research, Baylor University and University of Texas at Arlington researchers studied the biology and ecology of Prymnesium parvum (golden algae) in Texas lakes using a three-fold approach that involved system-wide monitoring, experimentation at the microcosm and mesocosm scales, and mathematical modeling. The following are conclusions, to date, regarding this organism's ecology and potential strategies for mitigation of blooms by this organism. In-lake monitoring revealed that golden algae are present throughout the year, even in lakes where blooms do not occur. Compilation of our field monitoring data with data collected by Texas Parks and Wildlife and Brazos River Authority (a period spanning a decade) revealed that inflow and salinity variables affect bloom formations. Thresholds for algae populations vary per lake, likely due to adaptations to local conditions, and also to variations in lake-basin morphometry, especially the presence of coves that may serve as hydraulic storage zones for P. parvum populations. More specifically, our in-lake monitoring showed that the highly toxic bloom that occurred in Lake Granbury in the winter of 2006/2007 was eliminated by increased river inflow events. The bloom was flushed from the system. The lower salinities that resulted contributed to golden algae not blooming in the following years. However, flushing is not an absolute requirement for bloom termination. Laboratory experiments have shown that growth of golden algae can occur at salinities ~1-2 psu but only when temperatures are also low. This helps to explain why blooms are possible during winter months in Texas lakes. Our in-lake experiments in Lake Whitney and Lake Waco, as well as our laboratory experiments, revealed that cyanobacteria, or some other bacteria capable of producing algicides, were able to prevent golden algae from blooming. Identification of this organism is a high priority as it may be a key to managing golden algae

Geophysical investigation of sentinel lakes in Lake, Seminole, Orange, and Volusia Counties, Florida

Science.gov (United States)

Reich, Christopher; Flocks, James; Davis, Jeffrey

2012-01-01

This study was initiated in cooperation with the St. Johns River Water Management District (SJRWMD) to investigate groundwater and surface-water interaction in designated sentinel lakes in central Florida. Sentinel lakes are a SJRWMD established set of priority water bodies (lakes) for which minimum flows and levels (MFLs) are determined. Understanding both the structure and lithology beneath these lakes can ultimately lead to a better understanding of the MFLs and why water levels fluctuate in certain lakes more so than in other lakes. These sentinel lakes have become important water bodies to use as water-fluctuation indicators in the SJRWMD Minimum Flows and Levels program and will be used to define long-term hydrologic and ecologic performance measures. Geologic control on lake hydrology remains poorly understood in this study area. Therefore, the U.S. Geological Survey investigated 16 of the 21 water bodies on the SJRWMD priority list. Geologic information was obtained by the tandem use of high-resolution seismic profiling (HRSP) and direct-current (DC) resistivity profiling to isolate both the geologic framework (structure) and composition (lithology). Previous HRSP surveys from various lakes in the study area have been successful in identifying karst features, such as subsidence sinkholes. However, by using this method only, it is difficult to image highly irregular or chaotic surfaces, such as collapse sinkholes. Resistivity profiling was used to complement HRSP by detecting porosity change within fractured or collapsed structures and increase the ability to fully characterize the subsurface. Lake Saunders (Lake County) is an example of a lake composed of a series of north-south-trending sinkholes that have joined to form one lake body. HRSP shows surface depressions and deformation in the substrate. Resistivity data likewise show areas in the southern part of the lake where resistivity shifts abruptly from approximately 400 ohm meters (ohm-m) along the

Great Lakes Literacy Principles

Science.gov (United States)

Fortner, Rosanne W.; Manzo, Lyndsey

2011-03-01

Lakes Superior, Huron, Michigan, Ontario, and Erie together form North America's Great Lakes, a region that contains 20% of the world's fresh surface water and is home to roughly one quarter of the U.S. population (Figure 1). Supporting a $4 billion sport fishing industry, plus $16 billion annually in boating, 1.5 million U.S. jobs, and $62 billion in annual wages directly, the Great Lakes form the backbone of a regional economy that is vital to the United States as a whole (see http://www.miseagrant.umich.edu/downloads/economy/11-708-Great-Lakes-Jobs.pdf). Yet the grandeur and importance of this freshwater resource are little understood, not only by people in the rest of the country but also by many in the region itself. To help address this lack of knowledge, the Centers for Ocean Sciences Education Excellence (COSEE) Great Lakes, supported by the U.S. National Science Foundation and the National Oceanic and Atmospheric Administration, developed literacy principles for the Great Lakes to serve as a guide for education of students and the public. These “Great Lakes Literacy Principles” represent an understanding of the Great Lakes' influences on society and society's influences on the Great Lakes.

Human impact on lake ecosystems: the case of Lake Naivasha, Kenya

African Journals Online (AJOL)

Lake Naivasha is a wetland of national and international importance. However, it is under constant anthropogenic pressures, which include the quest for socioeconomic development within the lake ecosystem itself as well as other activities within the catchment. The lake is an important source of fresh water in an otherwise ...

Lake whitefish and Diporeia spp. in the Great lakes: an overview

Science.gov (United States)

Nalepa, Thomas F.; Mohr, Lloyd C.; Henderson, Bryan A.; Madenjian, Charles P.; Schneeberger, Philip J.

2005-01-01

Because of growing concern in the Great Lakes over declines in abundance and growth of lake whitefish (Coregonus clupeaformis) and declines in abundance of the benthic amphipod Diporeia spp., a workshop was held to examine past and current trends, to explore trophic links, and to discuss the latest research results and needs. The workshop was divided into sessions on the status of populations in each of the lakes, bioenergetics and trophic dynamics, and exploitation and management. Abundance, growth, and condition of whitefish populations in Lakes Superior and Erie are stable and within the range of historical means, but these variables are declining in Lakes Michigan and Ontario and parts of Lake Huron. The loss of Diporeia spp., a major food item of whitefish, has been a factor in observed declines, particularly in Lake Ontario, but density-dependent factors also likely played a role in Lakes Michigan and Huron. The loss of Diporeia spp. is temporally linked to the introduction and proliferation of dreissenid mussels, but a direct cause for the negative response of Diporeia spp. has not been established. Given changes in whitefish populations, age-structured models need to be re-evaluated. Other whitefish research needs to include a better understanding of what environmental conditions lead to strong year-classes, improved aging techniques, and better information on individual population (stock) structure. Further collaborations between assessment biologists and researchers studying the lower food web would enhance an understanding of links between trophic levels.

Elementary School Students´ Approaches to Solving True/False Number Sentences (Métodos de Alumnos de Educación Primaria para la Resolución de Sentencias Numéricas Verdaderas y Falsas

Directory of Open Access Journals (Sweden)

Marta Molina

2008-01-01

Full Text Available This paper focuses on eight-year old students’ ways of approaching true/false number sentences. The data presented here belongs to a teaching experiment in which the use of relational thinking when solving number sentences was explicitly promoted. The study of the way of using this type of thinking and of students’ structure of attention, allow us to make distinctions and to provide a description of students’ different behaviours. Este artículo se centra en las formas en que alumnos de ocho años abordan la resolución de sentencias numéricas verdaderas y falsas. Los datos que se presentan pertenecen a un experimento de enseñanza en el cual se promovió explícitamente el uso del pensamiento relacional en la resolución de sentencias numéricas. El estudio del modo en que es usado este tipo de pensamiento y de la estructura de la atención de los alumnos, nos permite distinguir y aportar una descripción de los diferentes comportamientos de los alumnos.

Sources and distribution of microplastics in China's largest inland lake - Qinghai Lake.

Science.gov (United States)

Xiong, Xiong; Zhang, Kai; Chen, Xianchuan; Shi, Huahong; Luo, Ze; Wu, Chenxi

2018-04-01

Microplastic pollution was studied in China's largest inland lake - Qinghai Lake in this work. Microplastics were detected with abundance varies from 0.05 × 10 5 to 7.58 × 10 5 items km -2 in the lake surface water, 0.03 × 10 5 to 0.31 × 10 5 items km -2 in the inflowing rivers, 50 to 1292 items m -2 in the lakeshore sediment, and 2 to 15 items per individual in the fish samples, respectively. Small microplastics (0.1-0.5 mm) dominated in the lake surface water while large microplastics (1-5 mm) are more abundant in the river samples. Microplastics were predominantly in sheet and fiber shapes in the lake and river water samples but were more diverse in the lakeshore sediment samples. Polymer types of microplastics were mainly polyethylene (PE) and polypropylene (PP) as identified using Raman Spectroscopy. Spatially, microplastic abundance was the highest in the central part of the lake, likely due to the transport of lake current. Based on the higher abundance of microplastics near the tourist access points, plastic wastes from tourism are considered as an important source of microplastics in Qinghai Lake. As an important area for wildlife conservation, better waste management practice should be implemented, and waste disposal and recycling infrastructures should be improved for the protection of Qinghai Lake. Copyright © 2018 Elsevier Ltd. All rights reserved.

Outflows of groundwater in lakes: case study of Lake Raduńske Górne

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Cieśliński Roman

2014-12-01

Full Text Available The aim of the study was to locate and describe groundwater outflows in a selected lake basin. The study hypothesis was based on the fact that, according to the specialist literature, one of the forms of lake water supply is through groundwater outflows. It was also assumed that the lakes of the Kashubian Lake District are characterised by such a form of lake water supply. The time scope of the work included the period from January 2011 to September 2012. The spatial scope of the work included the area of Lake Raduńskie Górne, located in the Kashubian Lake District in north Poland. The research plot was in the north-eastern part of the lake. Office works were aimed at gathering and studying source materials and maps. Cartographic materials were analysed with the use of the MapInfo Professional 9.5. The purpose of the field work was to find the groundwater outflows in the basin of Lake Raduńskie Górne. During the field research diving was carried out in the lake. During the dive audiovisual documentation was conducted using a Nikon D90 camera with Ikelite underwater housing for Nikon D90 and an Ikelite DS 161 movie substrobe, as well as a GoPro HD HERO 2 Outdoor camera. During the project, four groundwater outflows were found. In order to examine these springs audiovisual and photographic documentation was made. To systematise the typology of the discovered springs, new nomenclature was suggested, namely under-lake springs with subtypes: an under-lake slope spring and under-lake offshore spring

Changing values of lake ecosystem services as a result of bacteriological contamination on Lake Trzesiecko and Lake Wielimie, Poland

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Cichoń Małgorzata

2017-12-01

Full Text Available Lake ecosystems, on the one hand, are affected by tourism, and on the other by development for tourism. Lake ecosystem services include: water with its self-cleaning processes, air with climate control processes, as well as flora and fauna. Utilisation of services leads to interventions in the structure of ecosystems and their processes. Only to a certain extent, this is specific to each type of environmental interference, remains within the limits of ecosystem resilience and does not lead to its degradation. One of the threats is bacteriological contamination, for which the most reliable sanitation indicator is Escherichia coli. In lake water quality studies it is assumed that the lakeshore cannot be a source of bacteria. It has been hypothesised that the problem of bacterial contamination can be serious for the places that do not have any infrastructure, especially sanitation. Consequently, the purpose of the study was to determine the extent to which lakeshore sanitation, in particular the level of bacteriological contamination, has an impact on the value of services provided by the selected lake ecosystems (Lake Trzesiecko and Lake Wielimie – Szczecinek Lake District. Five selected services related to lake ecosystems are: water, control over the spread of contagious diseases, aesthetic values, tourism and recreation, as well as the hydrological cycle with its self-cleaning function. Services, as well as the criteria adopted for evaluation, allow us to conclude that the services provided by the lake ecosystems are suitable to fulfill a recreation function. However, the inclusion of quality criteria for sanitary status has shown that the value of system services has dropped by as much as 50%. Value changes are visible primarily for water and aesthetic qualities. Such a significant decrease in the value of services clearly indicates the importance of the sanitary conditions of lakes and their appropriate infrastructure. In view of the

Resilience and Restoration of Lakes

Directory of Open Access Journals (Sweden)

Stephen R. Carpenter

1997-06-01

Full Text Available Lake water quality and ecosystem services are normally maintained by several feedbacks. Among these are nutrient retention and humic production by wetlands, nutrient retention and woody habitat production by riparian forests, food web structures that cha nnel phosphorus to consumers rather than phytoplankton, and biogeochemical mechanisms that inhibit phosphorus recycling from sediments. In degraded lakes, these resilience mechanisms are replaced by new ones that connect lakes to larger, regional economi c and social systems. New controls that maintain degraded lakes include runoff from agricultural and urban areas, absence of wetlands and riparian forests, and changes in lake food webs and biogeochemistry that channel phosphorus to blooms of nuisance al gae. Economic analyses show that degraded lakes are significantly less valuable than normal lakes. Because of this difference in value, the economic benefits of restoring lakes could be used to create incentives for lake restoration.

Yellowstone Lake Nanoarchaeota

Directory of Open Access Journals (Sweden)

Scott eClingenpeel

2013-09-01

Full Text Available Considerable Nanoarchaeota novelty and diversity were encountered in Yellowstone Lake, Yellowstone National Park, where sampling targeted lake floor hydrothermal vent fluids, streamers and sediments associated with these vents, and in planktonic photic zones in three different regions of the lake. Significant homonucleotide repeats (HR were observed in pyrosequence reads and in near full-length Sanger sequences, averaging 112 HR per 1,349 bp clone and could confound diversity estimates derived from pyrosequencing, resulting in false nucleotide insertions or deletions (indels. However, Sanger sequencing of two different sets of PCR clones (110 bp, 1349 bp demonstrated that at least some of these indels are real. The majority of the Nanoarchaeota PCR amplicons were vent associated; however, curiously, one relatively small Nanoarchaeota OTU (70 pyrosequencing reads was only found in photic zone water samples obtained from a region of the lake furthest removed from the hydrothermal regions of the lake. Extensive pyrosequencing failed to demonstrate the presence of an Ignicoccus lineage in this lake, suggesting the Nanoarchaeota in this environment are associated with novel Archaea hosts. Defined phylogroups based on near full-length PCR clones document the significant Nanoarchaeota 16S rRNA gene diversity in this lake and firmly establish a terrestrial clade distinct from the marine Nanoarcheota as well as from other geographical locations.

Contaminant trends in lake trout and walleye from the Laurentian Great Lakes

Science.gov (United States)

DeVault, David S.; Hesselberg, Robert J.; Rodgers, Paul W.; Feist, Timothy J.

1996-01-01

Trends in PCBs, DDT, and other contaminants have been monitored in Great Lakes lake trout and walleye since the 1970s using composite samples of whole fish. Dramatic declines have been observed in concentrations of PCB, ΣDDT, dieldrin, and oxychlordane, with declines initially following first order loss kinetics. Mean PCB concentrations in Lake Michigan lake trout increased from 13 μg/g in 1972 to 23 μg/g in 1974, then declined to 2.6 μg/g by 1986. Between 1986 and 1992 there was little change in concentration, with 3.5 μg/g observed in 1992. ΣDDT in Lake Michigan trout followed a similar trend, decreasing from 19.2 μg/g in 1970 to 1.1 μg/g in 1986, and 1.2 μg/g in 1992. Similar trends were observed for PCBs and ΣDDT in lake trout from Lakes Superior, Huron and Ontario. Concentrations of both PCB and ΣDDT in Lake Erie walleye declined between 1977 and 1982, after which concentrations were relatively constant through 1990. When originally implemented it was assumed that trends in the mean contaminant concentrations in open-lake fish would serve as cost effective surrogates to trends in the water column. While water column data are still extremely limited it appears that for PCBs in lakes Michigan and Superior, trends in lake trout do reasonably mimic those in the water column over the long term. Hypotheses to explain the trends in contaminant concentrations are briefly reviewed. The original first order loss kinetics used to describe the initial decline do not explain the more recent leveling off of contaminant concentrations. Recent theories have examined the possibilities of multiple contaminant pools. We suggest another hypothesis, that changes in the food web may have resulted in increased bioaccumulation. However, a preliminary exploration of this hypothesis using a change point analysis was inconclusive.

New evidence of cenozoic tectonism in the southeastern region of Brazil: the Barra de Sao Joao graben in Cabo Frio platform

International Nuclear Information System (INIS)

Mohriak, W.U.

1990-01-01

The western portion of the Campos Basin is limited by a hinge line that limits the deposition of pre-Aptian sediments in the offshore region. The Cabo Frio arch corresponds to a platform with smaller relative subsidence, where Tertiary sediments are deposited directly on shallow basement rocks. A conspicuous asymmetric graben occurs in the offshore region between Buzios and Macae. This rhomb-graben measures 20 km by 40 km, with the longer axis trending NE. The geological and geophysical characteristics of the Barra de Sao Joao graben supports a genetic affiliation with the onshore Taubate, Resende and Volta Redonda basins, rather than with the Campos Basin. The latter basin was formed in the Neocomian by rupturing of the Pangea, while the radiometric age determination of ankaramitic lavas near Volta Redonda suggests that the onshore basins were formed during the Eocene or Early Oligocene. A better understanding of the crustal geometry and the postulation of geodynamic models for these sedimentary basins will result from the integration of the onshore geology with the subsurface data presented in this paper. (author)

Pollution at Lake Mariut

International Nuclear Information System (INIS)

Nour ElDin, H.; Halim, S. N.; Shalby, E.

2004-01-01

Lake Mariut, south Alexandria, Egypt suffered in the recent decades from intensive pollution as a result of a continuous discharge of huge amounts of agriculture wastewater that contains a large concentration of the washed pesticides and fertilizers in addition to domestic and industrial untreated wastewater. The over flow from the lake is discharged directly to the sea through El-Max pumping station via EI-Umum drain. Lake Mariout is surrounded by a huge number of different industrial activities and also the desert road is cutting the lake, this means that a huge number of various pollutants cycle through the air and settle down in the lake, by the time and during different seasons these pollutants after accumulation and different chemical interactions will release again from the lake to the surrounding area affecting the surrounding zone

Long-Term Variability of Satellite Lake Surface Water Temperatures in the Great Lakes

Science.gov (United States)

Gierach, M. M.; Matsumoto, K.; Holt, B.; McKinney, P. J.; Tokos, K.

2014-12-01

The Great Lakes are the largest group of freshwater lakes on Earth that approximately 37 million people depend upon for fresh drinking water, food, flood and drought mitigation, and natural resources that support industry, jobs, shipping and tourism. Recent reports have stated (e.g., the National Climate Assessment) that climate change can impact and exacerbate a range of risks to the Great Lakes, including changes in the range and distribution of certain fish species, increased invasive species and harmful algal blooms, declining beach health, and lengthened commercial navigation season. In this study, we will examine the impact of climate change on the Laurentian Great Lakes through investigation of long-term lake surface water temperatures (LSWT). We will use the ATSR Reprocessing for Climate: Lake Surface Water Temperature & Ice Cover (ARC-Lake) product over the period 1995-2012 to investigate individual and interlake variability. Specifically, we will quantify the seasonal amplitude of LSWTs, the first and last appearances of the 4°C isotherm (i.e., an important identifier of the seasonal evolution of the lakes denoting winter and summer stratification), and interpret these quantities in the context of global interannual climate variability such as ENSO.

Lake Cadagno

DEFF Research Database (Denmark)

Tonolla, Mauro; Storelli, Nicola; Danza, Francesco

2017-01-01

Lake Cadagno (26 ha) is a crenogenic meromictic lake located in the Swiss Alps at 1921 m asl with a maximum depth of 21 m. The presence of crystalline rocks and a dolomite vein rich in gypsum in the catchment area makes the lake a typical “sulphuretum ” dominated by coupled carbon and sulphur...... cycles. The chemocline lies at about 12 m depth, stabilized by density differences of salt-rich water supplied by sub-aquatic springs to the monimolimnion and of electrolyte-poor surface water feeding the mixolimnion. Steep sulphide and light gradients in the chemocline support the growth of a large...... in the chemocline. Small-celled PSB together with the sulfate-reducing bacterium Desulfocapsa thiozymogenes sp. form stable aggregates in the lake, which represent small microenvironments with an internal sulphur cycle. Eukaryotic primary producers in the anoxic zones are dominated by Cryptomonas phaseolus...

Recent lake ice-out phenology within and among lake districts of Alaska, U.S.A.

Science.gov (United States)

Arp, Christopher D.; Jones, Benjamin M.; Grosse, Guido

2013-01-01

The timing of ice-out in high latitudes is a fundamental threshold for lake ecosystems and an indicator of climate change. In lake-rich regions, the loss of ice cover also plays a key role in landscape and climatic processes. Thus, there is a need to understand lake ice phenology at multiple scales. In this study, we observed ice-out timing on 55 large lakes in 11 lake districts across Alaska from 2007 to 2012 using satellite imagery. Sensor networks in two lake districts validated satellite observations and provided comparison with smaller lakes. Over this 6 yr period, the mean lake ice-out for all lakes was 27 May and ranged from 07 May in Kenai to 06 July in Arctic Coastal Plain lake districts with relatively low inter-annual variability. Approximately 80% of the variation in ice-out timing was explained by the date of 0°C air temperature isotherm and lake area. Shoreline irregularity, watershed area, and river connectivity explained additional variation in some districts. Coherence in ice-out timing within the lakes of each district was consistently strong over this 6 yr period, ranging from r-values of 0.5 to 0.9. Inter-district analysis of coherence also showed synchronous ice-out patterns with the exception of the two arctic coastal districts where ice-out occurs later (June–July) and climatology is sea-ice influenced. These patterns of lake ice phenology provide a spatially extensive baseline describing short-term temporal variability, which will help decipher longer term trends in ice phenology and aid in representing the role of lake ice in land and climate models in northern landscapes.

33 CFR 162.132 - Connecting waters from Lake Huron to Lake Erie; communications rules.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Connecting waters from Lake Huron to Lake Erie; communications rules. 162.132 Section 162.132 Navigation and Navigable Waters COAST... NAVIGATION REGULATIONS § 162.132 Connecting waters from Lake Huron to Lake Erie; communications rules. (a...

33 CFR 162.140 - Connecting waters from Lake Huron to Lake Erie; miscellaneous rules.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Connecting waters from Lake Huron to Lake Erie; miscellaneous rules. 162.140 Section 162.140 Navigation and Navigable Waters COAST... NAVIGATION REGULATIONS § 162.140 Connecting waters from Lake Huron to Lake Erie; miscellaneous rules. (a...

Real-estate lakes

Science.gov (United States)

Rickert, David A.; Spieker, Andrew Maute

1971-01-01

Since the dawn of civilization waterfront land has been an irresistible attraction to man. Throughout history he has sought out locations fronting on oceans, rivers, and lakes. Originally sought for proximity .to water supply and transportation, such locations are now sought more for their esthetic qualities and for recreation. Usable natural waterfront property is limited, however, and the more desirable sites in many of our urban areas have already been taken. The lack of available waterfront sites has led to the creation of many artificial bodies of water. The rapid suburbanization that has characterized urban growth in America since the end of World War II, together with increasing affluence and le-isure time, has created a ready market for waterfront property. Accordingly, lake-centered subdivisions and developments dot the suburban landscape in many of our major urban areas. Literally thousands of lakes surrounded by homes have materialized during this period of rapid growth. Recently, several "new town" communities have been planned around this lake-centered concept. A lake can be either an asset or a liaoility to a community. A clean, clear, attractively landscaped lake is a definite asset, whereas a weed-choked, foul-smelling mudhole is a distinct liability. The urban environment poses both problems and imaginative opportunities in the development of lakes. Creation of a lake causes changes in all aspects of the environment. Hydrologic systems and ecological patterns are usually most severely altered. The developer should be aware of the potential changes; it is not sufficient merely to build a dam across a stream or to dig a hole in the ground. Development of Gl a successful lake requires careful planning for site selection and design, followed by thorough and cc ntinual management. The purpose of this report is to describe the characteristics of real-estate lakes, to pinpoint potential pmblems, and to suggest possible planning and management guidelines

Lake Morphometry for NHD Lakes in California Region 18 HUC

Data.gov (United States)

U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

Lake Morphometry for NHD Lakes in Tennessee Region 6 HUC

Data.gov (United States)

U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

Lake Morphometry for NHD Lakes in Ohio Region 5 HUC

Data.gov (United States)

U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

Bathymetry of Lake Ontario

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry of Lake Ontario has been compiled as a component of a NOAA project to rescue Great Lakes lake floor geological and geophysical data and make it more...

Bathymetry of Lake Michigan

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry of Lake Michigan has been compiled as a component of a NOAA project to rescue Great Lakes lake floor geological and geophysical data and make it more...

Bathymetry of Lake Superior

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry of Lake Superior has been compiled as a component of a NOAA project to rescue Great Lakes lake floor geological and geophysical data and make it more...

Bathymetry of Lake Huron

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Bathymetry of Lake Huron has been compiled as a component of a NOAA project to rescue Great Lakes lake floor geological and geophysical data and make it more...

Circulation and sedimentation in a tidal-influenced fjord lake: Lake McKerrow, New Zealand

Science.gov (United States)

Pickrill, R. A.; Irwin, J.; Shakespeare, B. S.

1981-01-01

Lake McKerrow is a tide-influenced fjord lake, separated from the open sea by a Holocene barrier spit. Fresh, oxygenated waters of the epilimnion overlie saline, deoxygenated waters of the hypolimnion. During winter, water from the Upper Hollyford River interflows along the pycnocline, depositing coarse silt on the steep delta and transporting finer sediment down-lake. An extensive sub-lacustrine channel system on the foreset delta slope is possibly maintained by turbidity currents. Saline waters of the hypolimnion are periodically replenished. During high tides and low lake levels saline water flows into the lake and downslope into the lake basin as a density current in a well defined channel.

33 CFR 162.130 - Connecting waters from Lake Huron to Lake Erie; general rules.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Connecting waters from Lake Huron to Lake Erie; general rules. 162.130 Section 162.130 Navigation and Navigable Waters COAST GUARD... REGULATIONS § 162.130 Connecting waters from Lake Huron to Lake Erie; general rules. (a) Purpose. The...

O CARAMUJO AFRICANO EM CONTEXTO ESCOLAR: AS PERCEPÇÕES DE ESTUDANTES DO ENSINO FUNDAMENTAL E O ESTUDO DA HELMINTOFAUNA ASSOCIADA AO CARAMUJO EM BARRA DO PIRAÍ (RJ

Directory of Open Access Journals (Sweden)

Zilene Moreira Pereira

2012-01-01

Full Text Available The study investigates elementary students’ perception of the species Achatina fulica (African snail and the risks this mollusc may pose to the population of Barra do Piraí – in the state of Rio de Janeiro. The research involved questionnaires, focus groups and field observations, besides A. fulica specimens parasitological analysis. The results indicated the presence of snails infected with nematodes of medical and veterinary interest in the locality. The students have a negative perception of the snail, and there is great difference between their perceptions and scientific knowledge. Based on the contributions of the perceptions study and of Meaningful Learning Theory, guidelines are suggested so that strategies for teaching the content regarding the African snail at school environment can be developed.

Great Lakes Restoration Initiative Great Lakes Mussel Watch(2009-2014)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Following the inception of the Great Lakes Restoration Initiative (GLRI) to address the significant environmental issues plaguing the Great Lakes region, the...

33 CFR 162.134 - Connecting waters from Lake Huron to Lake Erie; traffic rules.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Connecting waters from Lake Huron to Lake Erie; traffic rules. 162.134 Section 162.134 Navigation and Navigable Waters COAST GUARD... REGULATIONS § 162.134 Connecting waters from Lake Huron to Lake Erie; traffic rules. (a) Detroit River. The...

33 CFR 162.138 - Connecting waters from Lake Huron to Lake Erie; speed rules.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Connecting waters from Lake Huron to Lake Erie; speed rules. 162.138 Section 162.138 Navigation and Navigable Waters COAST GUARD... REGULATIONS § 162.138 Connecting waters from Lake Huron to Lake Erie; speed rules. (a) Maximum speed limit for...

33 CFR 162.136 - Connecting waters from Lake Huron to Lake Erie; anchorage grounds.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Connecting waters from Lake Huron to Lake Erie; anchorage grounds. 162.136 Section 162.136 Navigation and Navigable Waters COAST GUARD... REGULATIONS § 162.136 Connecting waters from Lake Huron to Lake Erie; anchorage grounds. (a) In the Detroit...

Limnology of Botos Lake, a tropical crater lake in Costa Rica.

Science.gov (United States)

Umaña, G

2001-12-01

Botos Lake, located at the Poas Volcano complex (Costa Rica) was sampled eight times from 1994 to 1996 for physicochemical conditions of the water column and phytoplanktonic community composition. Depth was measured at fixed intervals in several transects across the lake to determine its main morphometric characteristics. The lake has an outlet to the north. It is located 2580 m above sea level and is shallow, with a mean depth of 1.8 m and a relative depth of 2.42 (surface area 10.33 ha, estimated volume 47.3 hm3). The lake showed an isothermal water column in all occasions, but it heats and cools completely according to weather fluctuations. Water transparency reached the bottom on most occasions (> 9 m). The results support the idea that the lake is polymictic and oligotrophic. The lake has at least 23 species of planktonic algae, but it was always dominated by dinoflagellates, especially Peridinium inconspicuum. The shore line is populated by a sparse population of Isoetes sp. and Eleocharis sp. mainly in the northern shore where the bottom has a gentle slope and the forest does not reach the shore.

Uso de Plantas com Fins Medicinais no Município de Barra – BA

Directory of Open Access Journals (Sweden)

Antonia Mirian Nogueira de Moura Guerra

2016-04-01

Full Text Available Este trabalho foi realizado no Assentamento de Reforma Agrária Sítio Novo, Barra–BA, objetivando conhecer as espécies medicinais e suas formas de uso adotadas pela população local. Entre Abril e Maio de 2015 foram realizadas entrevistas com aplicação de questionários estruturados. Todos os entrevistados fazem uso de plantas medicinais e cultivam alguma espécie em suas residências, usam as plantas por tradição familiar e por se tratar de um remédio natural  consomem principalmente quando estão doentes. Foram registradas 258 citações, nas quais foram relatadas a utilização de várias partes vegetais das 41 espécies, em 11 formas de preparo, com diferentes finalidades terapêuticas. As folhas e as cascas foram as partes mais utilizadas e os chás a principal forma de uso. As famílias Lamiaceae, Anacardiaceae, Myrtaceae e Rutaceae foram aquelas com maior representatividade e adoção medicinal. As espécies mais citadas foram a Cymbopogon citratus (Capim Santo – 15,5%, Lantana camara L. (Camará – 10,5%, Mentha sp.  (Hortelã Miúdo – 9,7%, Ocimum basilicum L. (Manjericão – 5,4% e Ruta graveolens L. (Arruda – 4,6% que corresponderam por 45,7% das citações. Entre as indicações terapêuticas citadas, destacam-se: doenças associadas ao sistema respiratório, indicações anti-inflamatórias, hipertensão, calmante e doenças associadas ao sistema digestivo. Nota-se que os moradores são detentores de um vasto conhecimento empírico relacionados à etnobotânica e as condições climáticas relacionadas ao manejo da flora da região e que o uso de plantas medicinais para fins terapêuticos é marcante, evidenciando que o uso popular de plantas medicinais está inserido significativamente nas esferas social e cultural dessa comunidade, o que assegurará a perpetuação dos costumes entre as próximas gerações.Use plants with medicinal purposes in Barra - BA MunicipalityAbstract: This work was carried out in the

75 FR 34934 - Safety Zone; Fireworks for the Virginia Lake Festival, Buggs Island Lake, Clarksville, VA

Science.gov (United States)

2010-06-21

...-AA00 Safety Zone; Fireworks for the Virginia Lake Festival, Buggs Island Lake, Clarksville, VA AGENCY... Fireworks for the Virginia Lake Festival event. This action is intended to restrict vessel traffic movement... Virginia Lake Festival, Buggs Island Lake, Clarksville, VA (a) Regulated Area. The following area is a...

Holocene lake-level fluctuations of Lake Aricota, Southern Peru

Science.gov (United States)

Placzek, C.; Quade, Jay; Betancourt, J.L.

2001-01-01

Lacustrine deposits exposed around Lake Aricota, Peru (17?? 22???S), a 7.5-km2 lake dammed by debris flows, provide a middle to late Holocene record of lake-level fluctuations. Chronological context for shoreline deposits was obtained from radiocarbon dating of vascular plant remains and other datable material with minimal 14C reservoir effects (Titicaca (16?? S), which is only 130 km to the northeast and shares a similar climatology. Comparisons with other marine and terrestrial records highlight emerging contradictions over the nature of mid-Holocene climate in the central Andes. ?? 2001 University of Washington.

Air-assisted boom sprayer and spray deposition on bean plants Assistência de ar em barra de pulverização e a deposição da calda em feijoeiro

Directory of Open Access Journals (Sweden)

Fernando Cesar Bauer

2003-01-01

Full Text Available The development of safe pesticide application techniques with low volume rates, frequency and spray drift, along with the need to obtain better control level of crop pest control levels, justify the air-assistance in boom sprayers. The aim of this research was to evaluate the spray deposition on bean plants with different nozzles and volume rates by air-assisted and non-assisted sprayers. A completely randomized experiment was carried out using copper oxide as a tracer (50% metalic copper for deposit evaluation. The artificial targets were fixed on the upper and under-side of the leaflets, at the top and lower third of the same plants under the spray boom. After application, targets were washed individually with an extracting solution of nitric acid (1.0 mol L-1. The tracer deposition on the artificial targets was quantified by atomic absorption spectrofotometry. The effects of air-assisted spray were not significant in relation to spray deposition 48 days after emergence of the bean plants.A possibilidade do desenvolvimento de técnicas de aplicação de produtos fitossanitários mais seguras, com menores volumes de calda, número de aplicações e deriva, aliados à necessidade de se obter melhores níveis de controle dos agentes nocivos às plantas cultivadas, justificam o uso da assistência de ar junto à barra de pulverização. Com o objetivo de avaliar a deposição da pulverização na cultura do feijoeiro (Phaseolus vulgaris, em presença e ausência da assistência de ar junto à barra de pulverização, com diferentes pontas de pulverização e volumes de calda, foi conduzido um experimento em delineamento inteiramente casualizado, utilizando-se como traçador o óxido cuproso. Alvos artificiais (papel filtro com 3 x 3 cm foram afixados nas superfícies adaxial e abaxial de folíolos posicionados nos terços superior e inferior de plantas, selecionadas ao acaso, distribuídas perpendicularmente ao deslocamento do pulverizador. Ap

Stable isotope and hydrogeochemical studies of Beaver Lake and Radok Lake, MacRobertson Land, East Antarctica

International Nuclear Information System (INIS)

Wand, U.; Hermichen, W.D.

1988-01-01

Beaver Lake and Radok Lake, the largest known epishelf lake and the deepest freshwater lake on the Antarctic continent, respectively, were isotopically (δ 2 H, δ 18 O) and hydrogeochemically studied. Radok Lake is an isothermal and nonstratified, i.e. homogeneous water body, while Beaver Lake is stratified with respect to temperature, salinity and isotopic composition. The results for the latter attest to freshwater (derived from snow and glacier melt) overlying seawater. (author)

Código de barras del ADN y sus posibles aplicaciones en el campo de la Entomología DNA barcoding and its possible applications to the field of Entomology

Directory of Open Access Journals (Sweden)

Analía A. Lanteri

2007-12-01

Full Text Available En este artículo se abordan algunos aspectos de la controversia sobre la iniciativa «Código de barras del ADN», y se hace hincapié en sus potenciales aplicaciones en Entomología. Esta iniciativa propone emplear información dentro de una misma región génica (gen mitocondrial de la Citocromo c Oxidasa I = COI, en todas las especies vivientes y con condiciones de secuenciación universalmente aceptadas y estandarizadas. En la actualidad, no pretende sustituir la taxonomía alfa y la filogenia sino agilizar las tareas de identificación, especialmente en el campo de la Biomedicina (identificación de patógenos, parásitos y vectores, el control de plagas (intercepción de especies invasoras, cualquiera sea su estado de desarrollo ontogenético y los estudios sobre conservación de la biodiversidad. Para arribar a una correcta delimitación de las especies biológicas es preciso contar con las secuencias de COI de numerosos individuos a lo largo de todo su rango geográfico y además, secuencias de genes nucleares e información morfológica y biológica detallada. Las «Unidades Evolutivas Significativas», identificadas sobre la base del «código de barras», podrían corresponder tanto a morfoespecies como a especies crípticas y a subespecies o linajes con diferentes preferencias de huéspedes. La integración del «código de barras del ADN», el trabajo de campo, las colecciones de museos y la investigación científica resultan imprescindibles para que esta herramienta redunde en avances significativos en el campo de la Sistemática Entomológica.This article deals with some of the most controversial issues of the DNA barcode initiative, focusing on its potential applications to Entomology. The barcoding proposes using information within the same gene region (Cytocrome c Oxidase I= COI mitochondrial gene, in all living species and under standard conditions of sequencing. At present, it does not attempt to replace alpha taxonomy or

Lake Generated Microseisms at Yellowstone Lake as a Record of Ice Phenology

Science.gov (United States)

Mohd Mokhdhari, A. A.; Koper, K. D.; Burlacu, R.

2017-12-01

It has recently been shown that wave action in lakes produces microseisms, which generate noise peaks in the period range of 0.8-1.2 s as recorded by nearby seismic stations. Such noise peaks have been observed at seven seismic stations (H17A, LKWY, B208, B944, YTP, YLA, and YLT) located within 2 km of the Yellowstone Lake shoreline. Initial work using 2016 data shows that the variations in the microseism signals at Yellowstone Lake correspond with the freezing and thawing of lake ice: the seismic noise occurs more frequently in the spring, summer, and fall, and less commonly in the winter. If this can be confirmed, then lake-generated microseisms could provide a consistent measure of the freezing and melting dates of high-latitude lakes in remote areas. The seismic data would then be useful in assessing the effects of climate change on the ice phenology of those lakes. In this work, we analyze continuous seismic data recorded by the seven seismic stations around Yellowstone Lake for the years of 1995 to 2016. We generate probability distribution functions of power spectral density for each station to observe the broad elevation of energy near a period of 1 s. The time dependence of this 1-s seismic noise energy is analyzed by extracting the power spectral density at 1 s from every processed hour. The seismic observations are compared to direct measurements of the dates of ice-out and freeze-up as reported by rangers at Yellowstone National Park. We examine how accurate the seismic data are in recording the freezing and melting of Yellowstone Lake, and how the accuracy changes as a function of the number of stations used. We also examine how sensitive the results are to the particular range of periods that are analyzed.

Monitoring climate signal transfer into the varved lake sediments of Lake Czechowskie, Poland

Science.gov (United States)

Groß-Schmölders, Miriam; Ott, Florian; Brykała, Dariusz; Gierszewski, Piotr; Kaszubski, Michał; Kienel, Ulrike; Brauer, Achim

2015-04-01

In 2012 we started a monitoring program at Lake Czechowskie, Poland, because the lake comprises a long Holocene time series of calcite varves until recent times. The aim of the program is to understand how environmental and climatic conditions influence the hydrological conditions and, ultimately, the sediment deposition processes of the lake. Lake Czechowskie is located in the north of Poland in the Pomeranian Lake District and is part of the national park Tuchola Forest. The landscape and the lake is formed by the glacier retreat after the last glaciation (Weichselian). Lake Czechowskie is a typical hardwater lake and has a length of 1.4 km, an average width of 600 m and a lake surface area of ca 4 km. The maximum depth of 32 m is reached in a rather small hollow in the eastern part of the lake. Two different types of sediment traps provide sediment samples with monthly resolution from different water depths (12m, 26m). In addition, hydrological data including water temperature in different depths, water inflow, throughflow and outflow and the depth of visibility are measured. These data allow to describe strength and duration of lake mixing in spring and autumn and its influence on sedimentation. The sediment samples were analyzed with respect to their dry weight (used to calculate mean daily sediment flux), their inorganic and organic carbon contents, the stable C- and O-isotopes of organic matter and calcite as well as N-isotopes of organic matter. For selected samples dominant diatom taxa are determined. Our first results demonstrate the strong influence of the long winter with ice cover until April in 2013 on the sedimentation. A rapid warming in only 9 days starting on April 9th from -0,3 C° to 15,2 C° resulted in fast ice break-up and a short but intensive lake mixing. In consequence of this short mixing period a strong algal bloom especially of Fragilaria and Crysophycea commenced in April and had its maximum in May. This bloom further induced biogenic

Is Lake Chabot Eutrophic?

Science.gov (United States)

Pellegrini, K.; Logan, J.; Esterlis, P.; Lew, A.; Nguyen, M.

2013-12-01

Introduction/Abstract: Lake Chabot is an integral part of the East Bay watershed that provides habitats for animals and recreation for humans year-round. Lake Chabot has been in danger of eutrophication due to excessive dumping of phosphorous and nitrogen into the water from the fertilizers of nearby golf courses and neighboring houses. If the lake turned out to be eutrophified, it could seriously impact what is currently the standby emergency water supply for many Castro Valley residents. Eutrophication is the excessive richness of nutrients such as nitrogen and phosphorus in a lake, usually as a result of runoff. This buildup of nutrients causes algal blooms. The algae uses up most of the oxygen in the water, and when it dies, it causes the lake to hypoxify. The fish in the lake can't breathe, and consequently suffocate. Other oxygen-dependant aquatic creatures die off as well. Needless to say, the eutrophication of a lake is bad news for the wildlife that lives in or around it. The level of eutrophication in our area in Northern California tends to increase during the late spring/early summer months, so our crew went out and took samples of Lake Chabot on June 2. We focused on the area of the lake where the water enters, known on the map as Honker Bay. We also took readings a ways down in deeper water for comparison's sake. Visually, the lake looked in bad shape. The water was a murky green that glimmered with particulate matter that swirled around the boat as we went by. In the Honker Bay region where we focused our testing, there were reeds bathed in algae that coated the surface of the lake in thick, swirling patterns. Surprisingly enough, however, our test results didn't reveal any extreme levels of phosphorous or nitrogen. They were slightly higher than usual, but not by any significant amount. The levels we found were high enough to stimulate plant and algae growth and promote eutrophication, but not enough to do any severe damage. After a briefing with a

Limnology of Eifel maar lakes

National Research Council Canada - National Science Library

Scharf, Burkhard W; Björk, Sven

1992-01-01

... & morphometry - Physical & chemical characteristics - Calcite precipitation & solution in Lake Laacher See - Investigations using sediment traps in Lake Gemundener Maar - Phytoplankton of Lake Weinfelder Maar...

Investigation of Residence and Travel Times in a Large Floodplain Lake with Complex Lake-River Interactions: Poyang Lake (China

Directory of Open Access Journals (Sweden)

Yunliang Li

2015-04-01

Full Text Available Most biochemical processes and associated water quality in lakes depends on their flushing abilities. The main objective of this study was to investigate the transport time scale in a large floodplain lake, Poyang Lake (China. A 2D hydrodynamic model (MIKE 21 was combined with dye tracer simulations to determine residence and travel times of the lake for various water level variation periods. The results indicate that Poyang Lake exhibits strong but spatially heterogeneous residence times that vary with its highly seasonal water level dynamics. Generally, the average residence times are less than 10 days along the lake’s main flow channels due to the prevailing northward flow pattern; whereas approximately 30 days were estimated during high water level conditions in the summer. The local topographically controlled flow patterns substantially increase the residence time in some bays with high spatial values of six months to one year during all water level variation periods. Depending on changes in the water level regime, the travel times from the pollution sources to the lake outlet during the high and falling water level periods (up to 32 days are four times greater than those under the rising and low water level periods (approximately seven days.

Sexual difference in PCB concentrations of lake trout (Salvelinus namaycush) from Lake Ontario

Science.gov (United States)

Madenjian, Charles P.; Keir, Michael J.; Whittle, D. Michael; Noguchi, George E.

2010-01-01

We determined polychlorinated biphenyl (PCB) concentrations in 61 female lake trout (Salvelinus namaycush) and 71 male lake trout from Lake Ontario (Ontario, Canada and New York, United States). To estimate the expected change in PCB concentration due to spawning, PCB concentrations in gonads and in somatic tissue of lake trout were also determined. In addition, bioenergetics modeling was applied to investigate whether gross growth efficiency (GGE) differed between the sexes. Results showed that, on average, males were 22% higher in PCB concentration than females in Lake Ontario. Results from the PCB determinations of the gonads and somatic tissues revealed that shedding of the gametes led to 3% and 14% increases in PCB concentration for males and females, respectively. Therefore, shedding of the gametes could not explain the higher PCB concentration in male lake trout. According to the bioenergetics modeling results, GGE of males was about 2% higher than adult female GGE, on average. Thus, bioenergetics modeling could not explain the higher PCB concentrations exhibited by the males. Nevertheless, a sexual difference in GGE remained a plausible explanation for the sexual difference in PCB concentrations of the lake trout.

L-Lake macroinvertebrate community

International Nuclear Information System (INIS)

Specht, W.L.

1996-06-01

To characterize the present benthic macroinvertebrate community of L-Lake, Regions 5 and 7 of the reservoir were sampled in September 1995 at the same locations sampled in 1988 and 1989 during the L-Lake monitoring program. The macroinvertebrate community of 1995 is compared to that of 1988 and 1989. The species composition of L-Lake's macroinvertebrate community has changed considerably since 1988-1989, due primarily to maturation of the reservoir ecosystem. L-Lake contains a reasonably diverse macroinvertebrate community that is capable of supporting higher trophic levels, including a diverse assemblage of fish species. The L-Lake macroinvertebrate community is similar to those of many other southeastern reservoirs, and there is no indication that the macroinvertebrate community is perturbed by chemical or physical stressors

L-Lake macroinvertebrate community

Energy Technology Data Exchange (ETDEWEB)

Specht, W.L.

1996-06-01

To characterize the present benthic macroinvertebrate community of L-Lake, Regions 5 and 7 of the reservoir were sampled in September 1995 at the same locations sampled in 1988 and 1989 during the L-Lake monitoring program. The macroinvertebrate community of 1995 is compared to that of 1988 and 1989. The species composition of L-Lake`s macroinvertebrate community has changed considerably since 1988-1989, due primarily to maturation of the reservoir ecosystem. L-Lake contains a reasonably diverse macroinvertebrate community that is capable of supporting higher trophic levels, including a diverse assemblage of fish species. The L-Lake macroinvertebrate community is similar to those of many other southeastern reservoirs, and there is no indication that the macroinvertebrate community is perturbed by chemical or physical stressors.

Water-quality and lake-stage data for Wisconsin lakes, water years 2012–2013

Science.gov (United States)

Manteufel, S. Bridgett; Robertson, Dale M.

2017-05-25

IntroductionThe U.S. Geological Survey (USGS), in cooperation with local and other agencies, collects data at selected lakes throughout Wisconsin. These data, accumulated over many years, provide a data base for developing an improved understanding of the water quality of lakes. To make these data available to interested parties outside the USGS, the data are published annually in this report series. The locations of water-quality and lake-stage stations in Wisconsin for water year 2012 are shown in figure 1. A water year is the 12-month period from October 1 through September 30. It is designated by the calendar year in which it ends. Thus, the period October 1, 2011 through September 30, 2012, is called “water year 2012.”The purpose of this report is to provide information about the chemical and physical characteristics of Wisconsin lakes. Data that have been collected at specific lakes, and information to aid in the interpretation of those data, are included in this report. Data collected include measurements of in-lake water quality and lake stage. Time series of Secchi depths, surface total phosphorus and chlorophyll a concentrations collected during non-frozen periods are included for all lakes. Graphs of vertical profiles of temperature, dissolved oxygen, pH, and specific conductance are included for sites where these parameters were measured. Descriptive information for each lake includes: location of the lake, area of the lake’s watershed, period for which data are available, revisions to previously published records, and pertinent remarks. Additional data, such as streamflow and water quality in tributary and outlet streams of some of the lakes, are published online at http://nwis.waterdata.usgs.gov/wi/nwis.Water-resources data, including stage and discharge data at most streamflow-gaging stations, are available online. The Wisconsin Water Science Center’s home page is at https://www.usgs.gov/centers/wisconsin-water-science-center. Information on

Hydrochemical determination of source water contributions to Lake Lungo and Lake Ripasottile (central Italy

Directory of Open Access Journals (Sweden)

Claire Archer

2016-12-01

Full Text Available Lake Lungo and Lake Ripasottile are two shallow (4-5 m lakes located in the Rieti Basin, central Italy, that have been described previously as surface outcroppings of the groundwater table. In this work, the two lakes as well as springs and rivers that represent their potential source waters are characterized physio-chemically and isotopically, using a combination of environmental tracers. Temperature and pH were measured and water samples were analyzed for alkalinity, major ion concentration, and stable isotope (δ2H, δ18O, δ13C of dissolved inorganic carbon, and δ34S and δ18O of sulfate composition.  Chemical data were also investigated in terms of local meteorological data (air temperature, precipitation to determine the sensitivity of lake parameters to changes in the surrounding environment. Groundwater represented by samples taken from Santa Susanna Spring was shown to be distinct with SO42- and Mg2+ content of 270 and 29 mg/L, respectively, and heavy sulfate isotopic composition (δ34S=15.2 ‰ and δ18O=10‰. Outflow from the Santa Susanna Spring enters Lake Ripasottile via a canal and both spring and lake water exhibits the same chemical distinctions and comparatively low seasonal variability. Major ion concentrations in Lake Lungo are similar to the Vicenna Riara Spring and are interpreted to represent the groundwater locally recharged within the plain. The δ13CDIC exhibit the same groupings as the other chemical parameters, providing supporting evidence of the source relationships. Lake Lungo exhibited exceptional ranges of δ13CDIC (±5 ‰ and δ2H, δ18O (±5 ‰ and ±7 ‰, respectively, attributed to sensitivity to seasonal changes. The hydrochemistry results, particularly major ion data, highlight how the two lakes, though geographically and morphologically similar, represent distinct hydrochemical facies. These data also show a different response in each lake to temperature and precipitation patterns in the basin that

Lake trout (Salvelinus namaycush) suppression for bull trout (Salvelinus confluentus) recovery in Flathead Lake, Montana, North America

Science.gov (United States)

Hansen, Michael J.; Hansen, Barry S; Beauchamp, David A.

2016-01-01

Non-native lake trout Salvelinus namaycush displaced native bull trout Salvelinus confluentus in Flathead Lake, Montana, USA, after 1984, when Mysis diluviana became abundant following its introduction in upstream lakes in 1968–1976. We developed a simulation model to determine the fishing mortality rate on lake trout that would enable bull trout recovery. Model simulations indicated that suppression of adult lake trout by 75% from current abundance would reduce predation on bull trout by 90%. Current removals of lake trout through incentivized fishing contests has not been sufficient to suppress lake trout abundance estimated by mark-recapture or indexed by stratified-random gill netting. In contrast, size structure, body condition, mortality, and maturity are changing consistent with a density-dependent reduction in lake trout abundance. Population modeling indicated total fishing effort would need to increase 3-fold to reduce adult lake trout population density by 75%. We conclude that increased fishing effort would suppress lake trout population density and predation on juvenile bull trout, and thereby enable higher abundance of adult bull trout in Flathead Lake and its tributaries.

Avaliação da acurácia de uma barra de luz utilizada na agricultura de precisão, em relação ao marcador de espuma Evaluation of the accuracy of a light bar used in precision farming compared to a foam marker

Directory of Open Access Journals (Sweden)

Fábio H. R. Baio

2001-05-01

Full Text Available Alguns equipamentos utilizados na agricultura de precisão têm, por finalidade, a melhoria das condições operacionais. A barra de luz é um equipamento utilizado para a orientação de um veículo em faixas adjacentes, diminuindo a sobreposição da operação agrícola entre passadas consecutivas e otimizando a eficiência da aplicação agrícola. O presente trabalho teve por objetivo a determinação da acurácia da barra de luz em relação ao marcador de espuma e a verificação da adaptação dos operadores à nova tecnologia. Para tanto, foram realizados dois ensaios em locais distintos, com operadores diferentes e foram comparados os erros de sobreposição e falhas nas passadas adjacentes de um pulverizador automotriz. Ocorreu alta adaptação dos operadores à nova tecnologia, devido a uma facilidade operacional maior em relação ao marcador de espuma. Concluiu-se que o marcador de espuma pode ser substituído pela barra de luz na aplicação de defensivos agrícolas.Some equipments are used in precision farming to improve operational conditions. A light bar is an equipment used to guide a vehicle in adjacent bands, reducing the overlap of the parallel swathing and optimizing the efficiency of the agricultural application. The objective of this work was to determine the accuracy of a light bar compared to a foam marker, and to verify the adaptation of the operators to this new technology. Experiments were conducted at two different places with several operators. The overlap errors and missed applications in the parallel swathing system were compared for both systems. There was a high adaptability of the operators to the light bar since this system was easier to operate than the foam marker. It was concluded that the light bar for the application of agricultural chemicals could replace the foam marker.

Lake Morphometry for NHD Lakes in Upper Colorado Region 14 HUC

Data.gov (United States)

U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

Lake Morphometry for NHD Lakes in North East Region 1 HUC

Data.gov (United States)

U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

Lake Morphometry for NHD Lakes in Lower Colorado Region 15 HUC

Data.gov (United States)

U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

Lake Morphometry for NHD Lakes in Upper Mississippi Region 7 HUC

Data.gov (United States)

U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

Lake Morphometry for NHD Lakes in Rio Grande Region 13 HUC

Data.gov (United States)

U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

Lake Morphometry for NHD Lakes in Pacific Northwest Region 17 HUC

Data.gov (United States)

U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

Lake Morphometry for NHD Lakes in Lower Mississippi Region 8 HUC

Data.gov (United States)

U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

Lake Morphometry for NHD Lakes in Texas-Gulf Region 12 HUC

Data.gov (United States)

U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

75 FR 22620 - Upper Klamath, Lower Klamath, Tule Lake, Bear Valley, and Clear Lake National Wildlife Refuges...

Science.gov (United States)

2010-04-29

...] Upper Klamath, Lower Klamath, Tule Lake, Bear Valley, and Clear Lake National Wildlife Refuges, Klamath..., Bear Valley, and Clear Lake National Wildlife Refuges (Refuges) located in Klamath County, Oregon, and..., Tule Lake, Bear Valley, and Clear Lake Refuges located in Klamath County, Oregon, and Siskiyou and...

The Key Lake project

International Nuclear Information System (INIS)

1991-01-01

Key Lake is located in the Athabasca sand stone basin, 640 kilometers north of Saskatoon, Saskatchewan, Canada. The three sources of ore at Key Lake contain 70 100 tonnes of uranium. Features of the Key Lake Project were described under the key headings: work force, mining, mill process, tailings storage, permanent camp, environmental features, worker health and safety, and economic benefits. Appendices covering the historical background, construction projects, comparisons of western world mines, mining statistics, Northern Saskatchewan surface lease, and Key Lake development and regulatory agencies were included

Palaeolimnological evidence of vulnerability of Lake Neusiedl (Austria) toward climate related changes since the last "vanished-lake" stage.

Science.gov (United States)

Tolotti, Monica; Milan, Manuela; Boscaini, Adriano; Soja, Gerhard; Herzig, Alois

2013-04-01

The palaeolimnological reconstruction of secular evolution of Euroepan Lakes with key socio-economical relevance respect to large (climate change) and local scale (land use, tourism) environmental changes, represents one of the objectives of the project EuLakes (European Lakes Under Environmental Stressors, Supporting lake governance to mitigate the impact of climate change, Reg. N. 2CE243P3), launched in 2010 within the Central European Inititiative. The project consortium comprises lakes of different morphology and prevalent human uses, including the meso-eutrophic Lake Neusiedl, the largest Austrian lake (total area 315 km2), and the westernmost shallow (mean depth 1.2 m) steppe lake of the Euro-Asiatic continent. The volume of Lake Neusiedl can potentially change over the years, in relation with changing balance between atmospheric precipitation and lake water evapotranspiration. Changing water budget, together with high lake salinity and turbidity, have important implications over the lake ecosystem. This contribution illustrates results of the multi-proxi palaeolimnological reconstruction of ecologial changes occurred in Lake Neusiedl during the last ca. 140 years, i.e. since the end of the last "vanished-lake" stage (1865-1871). Geochemical and biological proxies anticipate the increase in lake productivity of ca. 10 years (1950s) respect to what reported in the literature. Diatom species composition indicate a biological lake recovery in the late 1980s, and suggest a second increment in lake productivity since the late 1990s, possibly in relation with the progressive increase in the nitrogen input from agriculture. Abundance of diatoms typical of brackish waters indicated no significant long-term change in lake salinity, while variations in species toleranting dessiccation confirm the vulnerability of Lake Neusiedl toward climate-driven changes in the lake water balance. This fragility is aggravated by the the semi-arid climate conditions of the catchemnt

Hydrological and solute budgets of Lake Qinghai, the largest lake on the Tibetan Plateau

Energy Technology Data Exchange (ETDEWEB)

Jin, Zhangdong [Chinese Academy of Sciences (CAS), Beijing (China); National Cheng Kung Univ., Tainan City (Taiwan); You, Chen-Feng [National Cheng Kung Univ., Tainan City (Taiwan); Wang, Yi [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Shi, Yuewei [Bureau of Hydrology and Water Resources of Qinghai Province, Xining (China)

2009-12-04

Water level and chemistry of Lake Qinghai are sensitive to climate changes and are important for paleoclimatic implications. An accurate understanding of hydrological and chemical budgets is crucial for quantifying geochemical proxies and carbon cycle. Published results of water budget are firstly reviewed in this paper. Chemical budget and residence time of major dissolved constituents in the lake are estimated using reliable water budget and newly obtained data for seasonal water chemistry. The results indicate that carbonate weathering is the most important riverine process, resulting in dominance of Ca ²⁺ and DIC for river waters and groundwater. Groundwater contribution to major dissolved constituents is relatively small (4.2 ± 0.5%). Wet atmospheric deposition contributes annually 7.4–44.0% soluble flux to the lake, resulting from eolian dust throughout the seasons. Estimates of chemical budget further suggest that (1) the Buha-type water dominates the chemical components of the lake water, (2) Na⁺, Cl^-, Mg ²⁺ , and K⁺ in lake water are enriched owing to their conservative behaviors, and (3) precipitation of authigenic carbonates (low-Mg calcite, aragonite, and dolomite) transits quickly dissolved Ca ²⁺ into the bottom sediments of the lake, resulting in very low Ca ²⁺ in the lake water. Therefore, authigenic carbonates in the sediments hold potential information on the relative contribution of different solute inputs to the lake and the lake chemistry in the past.

Effects of acidity on primary productivity in lakes: phytoplankton. [Lakes Panther, Sagamore, and Woods

Energy Technology Data Exchange (ETDEWEB)

Hendrey, G R

1979-01-01

Relationships between phytoplankton communities and lake acidity are being studied at Woods Lake (pH ca. 4.9), Sagamore Lake (pH ca. 5.5), and Panther Lake (pH ca. 7.0). Numbers of phytoplankton species observed as of July 31, 1979 are Woods 27, Sagamore 38, and Panther 64, conforming to other observations that species numbers decrease with increasing acidity. Patterns of increasing biomass and productivity found in Woods Lake may be atypical of similar oligotrophic lakes in that they develop rather slowly instead of occuring very close to ice-out. Contributions of netplankton (net > 48 ..mu..m), nannoplankton (48 > nanno > 20 ..mu..m) and ultraplankton (20 > ultra >0.45 ..mu..m) to productivity per m/sup -2/ show that the smaller plankton are relatively more important in the more acid lakes. This pattern could be determined by nutrient availability (lake acidification leading to decreased availability of phosphorus). The amount of /sup 14/C-labelled dissolved photosynthate (/sup 14/C-DOM), as a percent of total productivity, is ordered Woods > Sagamore > Panther. This is consistent with a hypothesis that microbial heterotrophic activity is reduced with increasing acidity, but the smaller phytoplankton may be more leaky at low pH. (ERB)

Ecology of playa lakes

Science.gov (United States)

Haukos, David A.; Smith, Loren M.

1992-01-01

Between 25,000 and 30,000 playa lakes are in the playa lakes region of the southern high plains (Fig. 1). Most playas are in west Texas (about 20,000), and fewer, in New Mexico, Oklahoma, Kansas, and Colorado. The playa lakes region is one of the most intensively cultivated areas of North America. Dominant crops range from cotton in southern areas to cereal grains in the north. Therefore, most of the native short-grass prairie is gone, replaced by crops and, recently, grasses of the Conservation Reserve Program. Playas are the predominant wetlands and major wildlife habitat of the region.More than 115 bird species, including 20 species of waterfowl, and 10 mammal species have been documented in playas. Waterfowl nest in the area, producing up to 250,000 ducklings in wetter years. Dominant breeding and nesting species are mallards and blue-winged teals. During the very protracted breeding season, birds hatch from April through August. Several million shorebirds and waterfowl migrate through the area each spring and fall. More than 400,000 sandhill cranes migrate through and winter in the region, concentrating primarily on the larger saline lakes in the southern portion of the playa lakes region.The primary importance of the playa lakes region to waterfowl is as a wintering area. Wintering waterfowl populations in the playa lakes region range from 1 to 3 million birds, depending on fall precipitation patterns that determine the number of flooded playas. The most common wintering ducks are mallards, northern pintails, green-winged teals, and American wigeons. About 500,000 Canada geese and 100,000 lesser snow geese winter in the playa lakes region, and numbers of geese have increased annually since the early 1980’s. This chapter describes the physiography and ecology of playa lakes and their attributes that benefit waterfowl.

Relación del peso máximo con la fuerza aplicada y la potencia producida en un test creciente, en el ejercicio de press de banca plano con barra libre, en levantadores

OpenAIRE

Naclerio Ayllón, Fernando; Jiménez Gutiérrez, Alfonso; Forte Fernández, Daniel; Benito Peinado, Pedro J.

2006-01-01

Se evaluaron 9 levantadores que realizaron 2 test, en el ejercicio de press de banca plano con barra libre. Un test progresivo con pesos ligeros a máximos (TPR), y el test de una máxima repetición (1 MRD). Se midió la fuerza (f), velocidad (v) y potencia (p) con cada peso movilizado, se determinó el máximo peso desplazado en una única repetición (1 MR). Se observaron correlaciones significativas entre el valor de la 1 MR obtenida en el test de 1 MRPr y el de 1 MRD, entre la potencia máxima (a...

La Representación de la Mujer y los Ideales del Pensamiento Colombiano de Finales del Siglo XIX y Comienzos del Siglo XX: la Metáfora de la Falsa Inclusión

Directory of Open Access Journals (Sweden)

Adriana Yamile Suárez Reina

2014-01-01

Full Text Available A finales del siglo XIX y comienzos del siglo XX el proceso de construcción de la nación colombiana transitó por dos cami- nos adversos: el Periodo Radical -de corte liberal- y el Periodo de la Regeneración -de tinte conservador-. A partir de este contexto histórico-social se analiza la representación que se hace de la mujer durante este cambio de siglo, con el ánimo de evidenciar que el imaginario de género que se construyó allí está marcado por la metáfora de la falsa inclusión, es decir, que cada periodo a través de la noción que configura del poder, incluye a la mujer para, paradójicamente, excluirla. A partir de dicha metáfora este texto termina con un breve acercamiento a la propuesta de Tomás Carrasquilla y su personaje de Bárbara Caballero en La Marquesa de Yolombó y cómo este muestra la diatriba a la que se enfrentaba la mujer: tradición vs. independencia.

Excess unsupported sup(210)Pb in lake sediment from Rocky Mountain lakes

International Nuclear Information System (INIS)

Norton, S.A.; Hess, C.T.; Blake, G.M.; Morrison, M.L.; Baron, J.

1985-01-01

Sediment cores from four high-altitude (approximately 3200 m) lakes in Rocky Mountain National Park, Colorado, were dated by sup(210)Pb chronology. Background (supported) sup(210)Pb activities for the four cores range from 0.26 to 0.93 Beq/g dry weight, high for typical oligotrophic lakes. Integrated unsupported sup(210)Pb ranges from 0.81 (a typical value for most lakes) to 11.0 Beq/cmsup(2). The sup(210)Pb activity in the surface sediments ranges from 1.48 to 22.2 Beq/g dry weight. Sedimentation from Lake Louise, the most unusual of the four, has 22.2 Beq/g dry weight at the sediment surface, an integrated unsupported sup(210)Pb=11.0 Beq/cmsup(2), and supported sup(210)Pb=0.74 Beq/g dry weight. sup(226)Ra content of the sediment is insufficient to explain either the high unsupported sup(210)Pb or the sup(222)Rn content of the water column of Lake Louise, which averaged 96.2 Beq/L. We concluded that sup(222)Rn-rich groundwater entering the lake is the source of the high sup(222)Rn in the water column. This, in turn, is capable of supporting the unusually high sup(210)Pb flux to the sediment surface. Groundwater with high sup(222)Rn may control the sup(210)Pb budget of lakes where sediment cores have integrated unsupported sup(210)Pb greater than 2 Beq/cmsup(2)

Decline of the world's saline lakes

Science.gov (United States)

Wurtsbaugh, Wayne A.; Miller, Craig; Null, Sarah E.; Derose, R. Justin; Wilcock, Peter; Hahnenberger, Maura; Howe, Frank; Moore, Johnnie

2017-11-01

Many of the world's saline lakes are shrinking at alarming rates, reducing waterbird habitat and economic benefits while threatening human health. Saline lakes are long-term basin-wide integrators of climatic conditions that shrink and grow with natural climatic variation. In contrast, water withdrawals for human use exert a sustained reduction in lake inflows and levels. Quantifying the relative contributions of natural variability and human impacts to lake inflows is needed to preserve these lakes. With a credible water balance, causes of lake decline from water diversions or climate variability can be identified and the inflow needed to maintain lake health can be defined. Without a water balance, natural variability can be an excuse for inaction. Here we describe the decline of several of the world's large saline lakes and use a water balance for Great Salt Lake (USA) to demonstrate that consumptive water use rather than long-term climate change has greatly reduced its size. The inflow needed to maintain bird habitat, support lake-related industries and prevent dust storms that threaten human health and agriculture can be identified and provides the information to evaluate the difficult tradeoffs between direct benefits of consumptive water use and ecosystem services provided by saline lakes.

Conifer density within lake catchments predicts fish mercury concentrations in remote subalpine lakes

Science.gov (United States)

Eagles-Smith, Collin A.; Herring, Garth; Johnson, Branden L.; Graw, Rick

2016-01-01

Remote high-elevation lakes represent unique environments for evaluating the bioaccumulation of atmospherically deposited mercury through freshwater food webs, as well as for evaluating the relative importance of mercury loading versus landscape influences on mercury bioaccumulation. The increase in mercury deposition to these systems over the past century, coupled with their limited exposure to direct anthropogenic disturbance make them useful indicators for estimating how changes in mercury emissions may propagate to changes in Hg bioaccumulation and ecological risk. We evaluated mercury concentrations in resident fish from 28 high-elevation, sub-alpine lakes in the Pacific Northwest region of the United States. Fish total mercury (THg) concentrations ranged from 4 to 438 ng/g wet weight, with a geometric mean concentration (±standard error) of 43 ± 2 ng/g ww. Fish THg concentrations were negatively correlated with relative condition factor, indicating that faster growing fish that are in better condition have lower THg concentrations. Across the 28 study lakes, mean THg concentrations of resident salmonid fishes varied as much as 18-fold among lakes. We used a hierarchal statistical approach to evaluate the relative importance of physiological, limnological, and catchment drivers of fish Hg concentrations. Our top statistical model explained 87% of the variability in fish THg concentrations among lakes with four key landscape and limnological variables: catchment conifer density (basal area of conifers within a lake's catchment), lake surface area, aqueous dissolved sulfate, and dissolved organic carbon. Conifer density within a lake's catchment was the most important variable explaining fish THg concentrations across lakes, with THg concentrations differing by more than 400 percent across the forest density spectrum. These results illustrate the importance of landscape characteristics in controlling mercury bioaccumulation in fish.

Stable isotope and hydrogeochemical studies of Beaver Lake and Lake Radok, MacRobertson Land, East Antarctica

International Nuclear Information System (INIS)

Wand, U.; Hermichen, W.D.; Hoefling, R.; Muehle, K.

1987-01-01

Beaver Lake and Lake Radok, the largest known epishelf and the deepest freshwater lake on the Antarctic continent, respectively, were isotopically (δ 2 H, δ 18 O) and hydrogeochemically studied. Lake Radok is an isothermal and non-stratified, i.e. homogeneous water body, while Beaver Lake is stratified with respect to temperature, salinity and isotopic composition. The results for the latter attest to freshwater (derived from snow and glacier melt) overlying seawater. (author)

Environmental status of the Lake Michigan region. Volume 3. Chemistry of Lake Michigan

Energy Technology Data Exchange (ETDEWEB)

Torrey, M S

1976-05-01

The report is a synoptic review of data collected over the past twenty years on the chemistry of Lake Michigan. Changes in water quality and sediment chemistry, attributable to cultural and natural influences, are considered in relation to interacting processes and factors controlling the distribution and concentration of chemical substances within the Lake. Temperature, light, and mixing processes are among the important natural influences that affect nutrient cycling, dispersal of pollutants, and fate of materials entering the Lake. Characterization of inshore-offshore and longitudinal differences in chemical concentrations and sediment chemistry for the main body of the Lake is supplemented by discussion of specific areas such as Green Bay and Grand Traverse Bay. Residues, specific conductance, dissolved oxygen, major and trace nutrients, and contaminants are described in the following context: biological essentiality and/or toxicity, sources to the Lake, concentrations in the water column and sediments, chemical forms, seasonal variations and variation with depth. A summary of existing water quality standards, statutes, and criteria applicable to Lake Michigan is appended.

Assessment of the Great Lakes Marine Renewable Energy Resources: Characterizing Lake Erie Surge, Seiche and Waves

Science.gov (United States)

Farhadzadeh, A.; Hashemi, M. R.

2016-02-01

Lake Erie, the fourth largest in surface area, smallest in volume and shallowest among the Great Lakes is approximately 400 km long and 90 km wide. Short term lake level variations are due to storm surge generated by high winds and moving pressure systems over the lake mainly in the southwest-northeast direction, along the lakes longitudinal axis. The historical wave data from three active offshore buoys shows that significant wave height can exceed 5 m in the eastern and central basins. The long-term lake level data show that storm surge can reach up to 3 m in eastern Lake Erie. Owing its shallow depth, Lake Erie frequently experiences seiching motions, the low frequency oscillations that are initiated by storm surge. The seiches whose first mode of oscillations has a period of nearly 14.2 hours can last from several hours to days. In this study, the Lake Erie potential for power generation, primarily using storm surge and seiche and also waves are assessed. Given the cyclic lake level variations due to storm-induced seiching, a concept similar to that of tidal range development is utilized to assess the potential of storm surge and seiche energy harvesting mechanisms for power generation. In addition, wave energy resources of the Lake is characterized -. To achieve these objectives, the following steps are taken : (1) Frequency of occurrence for extreme storm surge and wave events is determined using extreme value analysis such as Peak-Over-Threshold method for the long-term water level and wave data; (2) Spatial and temporal variations of wave height, storm surge and seiche are characterized. The characterization is carried out using the wave and storm surge outputs from numerical simulation of a number of historical extreme events. The coupled ADCIRC and SWAN model is utilized for the modeling; (3) Assessment of the potentials for marine renewable power generation in Lake Erie is made. The approach can be extended to the other lakes in the Great Lakes region.

Combining lake and watershed characteristics with Landsat TM data for remote estimation of regional lake clarity

Science.gov (United States)

McCullough, Ian M.; Loftin, Cyndy; Sader, Steven A.

2012-01-01

Water clarity is a reliable indicator of lake productivity and an ideal metric of regional water quality. Clarity is an indicator of other water quality variables including chlorophyll-a, total phosphorus and trophic status; however, unlike these metrics, clarity can be accurately and efficiently estimated remotely on a regional scale. Remote sensing is useful in regions containing a large number of lakes that are cost prohibitive to monitor regularly using traditional field methods. Field-assessed lakes generally are easily accessible and may represent a spatially irregular, non-random sample of a region. We developed a remote monitoring program for Maine lakes >8 ha (1511 lakes) to supplement existing field monitoring programs. We combined Landsat 5 Thematic Mapper (TM) and Landsat 7 Enhanced Thematic Mapper Plus (ETM+) brightness values for TM bands 1 (blue) and 3 (red) to estimate water clarity (secchi disk depth) during 1990–2010. Although similar procedures have been applied to Minnesota and Wisconsin lakes, neither state incorporates physical lake variables or watershed characteristics that potentially affect clarity into their models. Average lake depth consistently improved model fitness, and the proportion of wetland area in lake watersheds also explained variability in clarity in some cases. Nine regression models predicted water clarity (R2 = 0.69–0.90) during 1990–2010, with separate models for eastern (TM path 11; four models) and western Maine (TM path 12; five models that captured differences in topography and landscape disturbance. Average absolute difference between model-estimated and observed secchi depth ranged 0.65–1.03 m. Eutrophic and mesotrophic lakes consistently were estimated more accurately than oligotrophic lakes. Our results show that TM bands 1 and 3 can be used to estimate regional lake water clarity outside the Great Lakes Region and that the accuracy of estimates is improved with additional model variables that reflect

Treating floodplain lakes of large rivers as study units for variables that vary within lakes; an evaluation using chlorophyll a and inorganic suspended solids data from floodplain lakes of the Upper Mississippi River

Science.gov (United States)

Gray, B.R.; Rogala, J.R.; Houser, J.N.

2013-01-01

Contiguous floodplain lakes ('lakes') have historically been used as study units for comparative studies of limnological variables that vary within lakes. The hierarchical nature of these studies implies that study variables may be correlated within lakes and that covariate associations may differ not only among lakes but also by spatial scale. We evaluated the utility of treating lakes as study units for limnological variables that vary within lakes based on the criteria of important levels of among-lake variation in study variables and the observation of covariate associations that vary among lakes. These concerns were selected, respectively, to ensure that lake signatures were distinguishable from within-lake variation and that lake-scale effects on covariate associations might provide inferences not available by ignoring those effects. Study data represented chlorophyll a (CHL) and inorganic suspended solids (ISS) data from lakes within three reaches of the Upper Mississippi River. Sampling occurred in summer from 1993 through 2005 (except 2003); numbers of lakes per reach varied from 7 to 19, and median lake area varied from 53 to 101 ha. CHL and ISS levels were modelled linearly, with lake, year and lake x year effects treated as random. For all reaches, the proportions of variation in CHL and ISS attributable to differences among lakes (including lake and lake x year effects) were substantial (range: 18%-73%). Finally, among-lake variation in CHL and ISS was strongly associated with covariates and covariate effects that varied by lakes or lake-years (including with vegetation levels and, for CHL, log(ISS)). These findings demonstrate the utility of treating floodplain lakes as study units for the study of limnological variables and the importance of addressing hierarchy within study designs when making inferences from data collected within floodplain lakes.

Global Lakes Sentinel Services: Evaluation of Chl-a Trends in Deep Clear Lakes

Science.gov (United States)

Cazzaniga, Ilaria; Giardino, Claudia; Bresciani, Mariano; Poser, Kathrin; Peters, Steef; Hommersom, Annelies; Schenk, Karin; Heege, Thomas; Philipson, Petra; Ruescas, Ana; Bottcher, Martin; Stelzer, Kerstin

2016-08-01

The aim of this study is the analysis of trend in the trophic level evolution in clear deep lakes which, being characterised by good quality state, are important socio- economic resources for their regions. The selected lakes are situated in Europe (Garda, Maggiore, Constance and Vättern), North America (Michigan) and Africa (Malawi and Tanganyika) and cover a range of eco- regions (continental, perialpine, boreal, rift valley) distributed globally.To evaluate trophic level tendency we mainly focused on chlorophyll-a concentrations (chl-a) which is a direct proxy of trophic status. The chl-a concentrations were obtained from 5216 cloud-free MERIS imagery from 2002 to 2012.The 'GLaSS RoIStats tool' available within the GLaSS project was used to extract chl-a in a number of region of interests (ROI) located in pelagic waters as well as some few other stations depending on lakes morphology. For producing the time-series trend, these extracted data were analysed with the Seasonal Kendall test.The results overall show almost stable conditions with a slight increase in concentration for lakes Maggiore, Constance, and the Green Bay of Lake Michigan; a slight decrease for lakes Garda and Tanganyika and absolutely stable conditions for lakes Vättern and Malawi.The results presented in this work show the great capability of MERIS to perform trend tests analysis on trophic status with focus on chl-a concentration. Being chl-a also a key parameter in water quality monitoring plans, this study also supports the managing practices implemented worldwide for using the water of the lakes.

Benthic-planktonic coupling, regime shifts, and whole-lake primary production in shallow lakes.

Science.gov (United States)

Genkai-Kato, Motomi; Vadeboncoeur, Yvonne; Liboriussen, Lone; Jeppesen, Erik

2012-03-01

Alternative stable states in shallow lakes are typically characterized by submerged macrophyte (clear-water state) or phytoplankton (turbid state) dominance. However, a clear-water state may occur in eutrophic lakes even when macrophytes are absent. To test whether sediment algae could cause a regime shift in the absence of macrophytes, we developed a model of benthic (periphyton) and planktonic (phytoplankton) primary production using parameters derived from a shallow macrophyte-free lake that shifted from a turbid to a clear-water state following fish removal (biomanipulation). The model includes a negative feedback effect of periphyton on phosphorus (P) release from sediments. This in turn induces a positive feedback between phytoplankton production and P release. Scenarios incorporating a gradient of external P loading rates revealed that (1) periphyton and phytoplankton both contributed substantially to whole-lake production over a broad range of external P loading in a clear-water state; (2) during the clear-water state, the loss of benthic production was gradually replaced by phytoplankton production, leaving whole-lake production largely unchanged; (3) the responses of lakes to biomanipulation and increased external P loading were both dependent on lake morphometry; and (4) the capacity of periphyton to buffer the effects of increased external P loading and maintain a clear-water state was highly sensitive to relationships between light availability at the sediment surface and the of P release. Our model suggests a mechanism for the persistence of alternative states in shallow macrophyte-free lakes and demonstrates that regime shifts may trigger profound changes in ecosystem structure and function.

Changes in depth occupied by Great Lakes lake whitefish populations and the influence of survey design

Science.gov (United States)

Rennie, Michael D.; Weidel, Brian C.; Claramunt, Randall M.; Dunlob, Erin S.

2015-01-01

Understanding fish habitat use is important in determining conditions that ultimately affect fish energetics, growth and reproduction. Great Lakes lake whitefish (Coregonus clupeaformis) have demonstrated dramatic changes in growth and life history traits since the appearance of dreissenid mussels in the Great Lakes, but the role of habitat occupancy in driving these changes is poorly understood. To better understand temporal changes in lake whitefish depth of capture (Dw), we compiled a database of fishery-independent surveys representing multiple populations across all five Laurentian Great Lakes. By demonstrating the importance of survey design in estimating Dw, we describe a novel method for detecting survey-based bias in Dw and removing potentially biased data. Using unbiased Dw estimates, we show clear differences in the pattern and timing of changes in lake whitefish Dw between our reference sites (Lake Superior) and those that have experienced significant benthic food web changes (lakes Michigan, Huron, Erie and Ontario). Lake whitefish Dw in Lake Superior tended to gradually shift to shallower waters, but changed rapidly in other locations coincident with dreissenid establishment and declines in Diporeia densities. Almost all lake whitefish populations that were exposed to dreissenids demonstrated deeper Dw following benthic food web change, though a subset of these populations subsequently shifted to more shallow depths. In some cases in lakes Huron and Ontario, shifts towards more shallow Dw are occurring well after documented Diporeia collapse, suggesting the role of other drivers such as habitat availability or reliance on alternative prey sources.

Historical changes to Lake Washington and route of the Lake Washington Ship Canal, King County, Washington

Science.gov (United States)

Chrzastowski, Michael J.

1983-01-01

Lake Washington, in the midst of the greater Seattle metropolitan area of the Puget Sound region (fig. 1), is an exceptional commercial, recreational, and esthetic resource for the region . In the past 130 years, Lake Washington has been changed from a " wild " lake in a wilderness setting to a regulated lake surrounded by a growing metropolis--a transformation that provides an unusual opportunity to study changes to a lake's shoreline and hydrologic characteristics -resulting from urbanization.

Climatic changes inferred fron analyses of lake-sediment cores, Walker Lake, Nevada

International Nuclear Information System (INIS)

Yang, In Che.

1989-01-01

Organic and inorganic fractions of sediment collected from the bottom of Walker Lake, Nevada, have been dated by carbon-14 techniques. Sedimentation rates and the organic-carbon content of the sediment were correlated with climatic change. The cold climate between 25,000 and 21,000 years ago caused little runoff, snow accumulation on the mountains, and rapid substantial glacial advances; this period of cold climate resulted in a slow sedimentation rate (0.20 millimeter per year) and in a small organic-carbon content in the sediment. Also, organic-carbon accumulation rates in the lake during this period were slow. The most recent period of slow sedimentation rate and small organic-carbon content occurred between 10,000 and 5500 years ago, indicative of low lake stage and dry climatic conditions. This period of dry climate also was evidenced by dry conditions for Lake Lahontan in Nevada and Searles Lake in California, as cited in the literature. Walker Lake filled rapidly with water between 5500 and 4500 years ago. The data published in this report was not produced under an approved Site Investigation Plan (SIP) or Study Plan (SP) and will not be used in the licensing process. 10 refs., 3 figs., 2 tabs

Survey and assessment of post volcanic activities of a young caldera lake, Lake Cuicocha, Ecuador

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G. Gunkel

2009-05-01

Full Text Available Cuicocha is a young volcano adjacent to the inactive Pleistocene Cotacachi volcano complex, located in the western cordilleras of the Ecuadorian Andes. A series of eruptions with intensive ash emission and collapse of the caldera occurred around 4500–3000 y BP. A crater 3.2 km in diameter and a maximum depth of 450 m was formed. Further eruptions of the volcano occurred 1300 y BP and formed four smaller domes within the caldera. Over the last few hundred years, a caldera lake has developed, with a maximum depth of 148 m. The lake water is characterized by sodium carbonate with elevated concentrations of manganese, calcium and chloride. Nowadays, an emission of gases, mainly CO₂, and an input of warm spring water occur in Lake Cuicocha. The zone of high activity is in the western basin of the lake at a depth of 78 m, and continuous gas emissions with sediment resuspension were observed using sonar. In the hypolimnion of the lake, CO₂ accumulation occurs up to 0.2% saturation, but the risk of a limnic eruption can be excluded at present. The lake possesses monomictic stratification behaviour, and during overturn an intensive gas exchange with the atmosphere occurs. Investigations concerning the sedimentation processes of the lake suggest only a thin sediment layer of up to 10–20 cm in the deeper lake basin; in the western bay, in the area of gas emissions, the lake bottom is partly depleted of sediment in the form of holes, and no lake colmation exists. Decreases in the lake water level of about 30 cm y⁻¹ indicate a percolation of water into fractures and fissures of the volcano, triggered by a nearby earthquake in 1987.

A Synoptic Climatology of Heavy Rain Events in the Lake Eyre and Lake Frome Catchments

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Michael John Pook

2014-11-01

Full Text Available The rare occasions when Lake Eyre in central, southern Australia fills with water excite great interest and produce major ecological responses. The filling of other smaller lakes such as Lake Frome, have less impact but can contribute important information about the current and past climates of these arid regions. Here, the dominant synoptic systems responsible for heavy rainfall over the catchments of Lake Eyre and Lake Frome since 1950 are identified and compared. Heavy rain events are defined as those where the mean catchment rainfall for 24 hours reaches a prescribed threshold. There were 25 such daily events at Lake Eyre and 28 in the Lake Frome catchment. The combination of a monsoon trough at mean sea level and a geopotential trough in the mid-troposphere was found to be the synoptic system responsible for the majority of the heavy rain events affecting Lake Eyre and one in five of the events at Lake Frome. Complex fronts where subtropical interactions occurred with Southern Ocean fronts also contributed over 20% of the heavy rainfall events in the Frome catchment. Surface troughs without upper air support were found to be associated with 10% or fewer of events in each catchment, indicating that mean sea level pressure analyses alone do not adequately capture the complexity of the heavy rainfall events. At least 80% of the heavy rain events across both catchments occurred when the Southern Oscillation Index (SOI was in its positive phase, and for Lake Frome, the SOI exceeded +10 on 60% of occasions, suggesting that the background atmospheric state in the Pacific Ocean was tilted towards La Niña. Hydrological modeling of the catchments suggests that the 12-month running mean of the soil moisture in a sub-surface layer provides a low frequency filter of the precipitation and matches measured lake levels relatively well.

Efeito da velocidade do ar em barra de pulverização na deposição de produtos fitossanitários em feijoeiro Efect of the air speed in air-assisted sprayer on bean crop pesticide spray deposition

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Carlos Gilberto Raetano

2003-01-01

Full Text Available Com o objetivo de avaliar o efeito da variação da velocidade do ar em barra de pulverização na deposição da calda na cultura do feijoeiro (Phaseolus vulgaris, realizou-se o experimento em 9 e 10 de outubro de 2000, no Centro de Pesquisas Agronômicas - Cyanamid, em Iracemápolis (SP, em delineamento inteiramente casualizado, aos 48 dias após a emergência (DAE. Para isso, convencionou-se que a rotação máxima do ventilador, medida com o auxílio de fototacômetro, possibilitou a obtenção da velocidade máxima do ar na barra de pulverização e, a partir daí, níveis de 50% e 75% da velocidade máxima do ar. Alvos artificiais foram fixados na superfície adaxial e na abaxial de folíolos posicionados, nos terços superior e inferior das plantas selecionadas, ao acaso, e distribuídas perpendicularmente ao deslocamento do pulverizador. O óxido cuproso (50% de cobre metálico foi o traçador utilizado em pulverização e a determinação quantitativa dos depósitos feita com o uso da espectrofotometria de absorção atômica. Os resultados sugerem que a variação da velocidade do ar na barra pulverizadora não influenciou sobre os níveis de depósitos no feijoeiro, aos 48 DAE, nas condições do presente trabalho.The aim of this research was to evaluate the effects of air speed in air-assisted sprayer on bean crop (Phaseolus vulgaris spray deposition. The experiment was carried out at 48 days after crop emergence and the experimental design was randomized. The maximum air speed in spray boom was obtained with the maximum of the fan rotation by a phototachometer. The middle and third air speed were obtained with lower fan rotation. The tracer used in the spray solution was copper oxid (50% of the metalic copper. It was measured by atomic spectrophotometry absorption equipment. The targets were fixed on the under and upper-side of the leaves, in the top and lower third of the same plant under the spray boom. The effects of variation

Spatio-temporal variation of the pink shrimp Farfantepenaeus paulensis (Crustacea, Decapoda, Penaeidae associated to the seasonal overture of the sandbar in a subtropical lagoon Variação espaço-temporal do camarão rosa Farfantepenaeus paulensis (Crustacea, Decapoda, Penaeidae associado à abertura sazonal da barra de conexão com o mar em uma lagoa subtropical

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Nicolle C Ferreira

2009-12-01

pelos pescadores não são mais eficientes devido aos conflitos com o turismo e a gestão pública e ambiental. A dinâmica de abertura artificial e reestruturação natural do banco de areia no canal de contato da lagoa com o mar é considerada um problema socio-ecológico central no local. Neste estudo foi avaliada a variação na biomassa e abundância do F. paulensis ao longo do ano e em um gradiente espacial a partir do canal da barra e até o interior da lagoa. Foram realizadas coletas mensais de fevereiro de 2004 a fevereiro de 2005 com tarrafa de 27 mm de malha nas quatro lagoas que compõe a Lagoa de Ibiraquera, em três pontos em cada lagoa. Um número pequeno de grandes camarões foi significativamente (p < 0,05 capturado na área mais interna da lagoa, enquanto que maior biomassa e abundância de pequenos camarões foram observadas significativamente (p < 0,05 próximas à barra. Esses resultados sugerem que as áreas mais internas da lagoa funcionam como refúgio para o crescimento das espécies e mostram o papel do canal na migração dos camarões para dentro da lagoa. Os valores de biomassa e abundância foram significativamente (p < 0,05 maiores nos meses mais quentes, independentemente da barra estar aberta ou fechada. O estoque de camarão poderia aumentar caso houvesse uma abertura da barra durante o período natural de entrada de pós-larvas. Além disso, a abertura da barra durante o verão, associada a medidas de conservação das águas do canal da barra, pode implementar os estoques costeiros.

Expanding models of lake trophic state to predict cyanobacteria in lakes

Science.gov (United States)

Background/Question/Methods: Cyanobacteria are a primary taxonomic group associated with harmful algal blooms in lakes. Understanding the drivers of cyanobacteria presence has important implications for lake management and for the protection of human and ecosystem health. Chlor...

The ralationship between the Tamarix spp. growth and lake level change in the Bosten Lake,northwest China

Science.gov (United States)

Ye, Mao; Hou, JiaWen

2015-04-01

Dendrochronology methods are used to analyze the characteristics of Tamarix spp. growth in Bosten Lake. Based on the long-term annual and monthly data of lake level, this paper models the relationship between ring width of Tamarix spp. and lake level change. The sensitivity index is applied to determine the rational change range of lake level for protecting the Tamarix spp. growth. The results show that :( 1) the annual change of lake level in Bosten Lake has tree evident stages from 1955 to 2012. The monthly change of lake level has two peak values and the seasonal change is not significant; (2) the average value of radical width of Tamarix spp. is 3.39mm. With the increment of Tamarix spp. annual growth , the average radical width has a decreasing trend, which is similar to the annual change trend of lake level in the same years ;( 3) the response of the radical width of Tamarix spp. to annual change of lake level is sensitive significantly. When the lake level is 1045.66m, the Sk value of radical width of Tamarix spp. appears minimum .when the lake level is up to1046.27m, the Sk value is maximum. Thus the sensitivity level of radical width of Tamarix spp. is 1045.66- 1046.27m which could be regarded as the rational lake level change range for protecting the Tamarix spp. growth.

Desempenho na barra de tração de um trator agrícola de pneus, alimentado com misturas de óleo diesel e óleo de soja reutilizado

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Wagner da Cunha Siqueira

2013-12-01

Full Text Available O petróleo é a principal fonte de energia para motores de combustão interna, possibilitando sua transformação em energia mecânica. A dependência do petróleo conduz à necessidade de alternativas, mediante o cultivo de matérias-primas renováveis. Os problemas atuais são os custos dos biocombustíveis, que são maiores que dos derivados do petróleo, e o fato de que não existem muitos motores de combustão adequados ao uso de óleos vegetais. Em vista disso, são necessárias mais investigações quanto às técnicas de produção e de refino dos biocombustíveis e, ainda, à adequação de motores ao uso de óleos vegetais, para que estes possam ser uma alternativa viável. O objetivo deste trabalho foi caracterizar as diferentes misturas e avaliar o desempenho de um trator agrícola de pneus, utilizando misturas de óleo Diesel (OD com óleo de soja reutilizável (OSR. Primeiramente, foi realizado um estudo de densidade, viscosidade das misturas e comportamento da temperatura do OD no sistema de alimentação de combustível no motor. Após as análises, verificou-se, por meio de ensaios na barra de tração, o desempenho das misturas de OD e OSR. As principais conclusões deste trabalho foram: a densidade e viscosidade das misturas sofrem variações com o aumento da quantidade de OSR e com a variação da temperatura. Para as avaliações na barra de tração, os melhores resultados observados no rendimento do trator foram verificados com o aumento das percentagens de mistura (25% OSR, para carga N, 25, 75 e 100% OSR, para a quarta marcha, como carga, e 75 e 100% OSR, para a terceira, segunda e primeira marcha, como carga.

Lake Chad, Chad, Africa

Science.gov (United States)

1992-01-01

Hydrologic and ecologic changes in the Lake Chad Basin are shown in this Oct 1992 photograph. In space photo documentation, Lake Chad was at its greatest area extent (25,000 sq. km.) during Gemini 9 in June 1966 (see S66-38444). Its reduction during the severe droughts from 1968 to 1974 was first noted during Skylab (1973-1974). After the drought began again in 1982, the lake reached its minimum extent (1,450 sq. km.) in Space Shuttle photographs taken in 1984 and 1985. In this STS-52 photograph, Lake Chad has begun to recover. The area of the open water and interdunal impoundments in the southern basin (the Chari River Basin) is estimated to be 1,900 to 2100 sq. km. Note the green vegetation in the valley of the K'Yobe flow has wetted the northern lake basin for the first time in several years. There is evidence of biomass burning south of the K'Yobe Delta and in the vegetated interdunal areas near the dike in the center of the lake. Also note the dark 'Green Line' of the Sahel (the g

Lake Morphometry for NHD Lakes in Souris Red Rainy Region 9 HUC

Data.gov (United States)

U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

Lake Morphometry for NHD Lakes in Arkansas White Red Region 11 HUC

Data.gov (United States)

U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

Influence of permafrost on lake terraces of Lake Heihai (NE Tibetan Plateau)

Science.gov (United States)

Lockot, Gregori; Hartmann, Kai; Wünnemann, Bernd

2013-04-01

The Tibetan Plateau (TP) is one of the key regions for climatic global change. Besides the poles the TP is the third highest storage of frozen water in glaciers. Here global warming is three times higher than in the rest of the world. Additionally the TP provides water for billions of people and influences the moisture availability from the Indian and East Asian monsoon systems. During the Holocene extent and intensity of the monsoonal systems changed. Hence, in the last decades, a lot of work was done to reconstruct timing and frequency of monsoonal moisture, to understand the past and give a better forecast for the future. Comparative workings often show very heterogeneous patterns of timing and frequency of the Holocene precipitation and temperature maximum, emphasizing the local importance of catchment dynamics. In this study we present first results of lake Heihai (36°N, 93°15'E, 4500m a.s.l.), situated at the north-eastern border of the TP. The lake is surrounded by a broad band of near-shore lake sediments, attesting a larger lake extent in the past. These sediments were uplifted by permafrost, reaching nowadays heights ca. +8 meters above present lake level. Due to the uplift one of the main inflows was blocked and the whole hydrology of the catchment changed. To quantify the uplift of permafrost Hot Spot Analysis were accomplished at a DEM of the near-shore area. As a result regions of high permafrost uplift and those which mirror the original height of lake ground were revealed. The most obvious uplift took place in the northern and western part of the lake, where the four uplift centers are located. In contrast the southern and eastern areas show a rather degraded pattern (probably by fluvial erosion, thermokarst, etc.). The ancient lake bottom, without permafrost uplift was estimated to be 4-6 meters above the modern lake level. For a better understanding of permafrost interaction inside the terrace bodies a 5m sediment profile was sampled and

Lake sediments as natural seismographs: Earthquake-related deformations (seismites) in central Canadian lakes

Science.gov (United States)

Doughty, M.; Eyles, N.; Eyles, C. H.; Wallace, K.; Boyce, J. I.

2014-11-01

Central Canada experiences numerous intraplate earthquakes but their recurrence and source areas remain obscure due to shortness of the instrumental and historic records. Unconsolidated fine-grained sediments in lake basins are 'natural seismographs' with the potential to record ancient earthquakes during the last 10,000 years since the retreat of the Laurentide Ice Sheet. Many lake basins are cut into bedrock and are structurally-controlled by the same Precambrian basement structures (shear zones, terrane boundaries and other lineaments) implicated as the source of ongoing mid-plate earthquake activity. A regional seismic sub-bottom profiling of lakes Gull, Muskoka, Joseph, Rousseau, Ontario, Wanapitei, Fairbanks, Vermilion, Nipissing, Georgian Bay, Mazinaw, Simcoe, Timiskaming, Kipawa, Parry Sound and Lake of Bays, encompassing a total of more than 2000 kilometres of high-resolution track line data supplemented by multibeam and sidescan sonar survey records show a consistent sub-bottom stratigraphy of relatively-thick lowermost lateglacial facies composed of interbedded semi-transparent mass flow facies (debrites, slumps) and rhythmically-laminated silty-clays. Mass flows together with cratered ('kettled') lake floors and associated deformations reflect a dynamic ice-contact glaciolacustrine environment. Exceptionally thick mass flow successions in Lake Timiskaming along the floor of the Timiskaming Graben within the seismically-active Western Quebec Seismic Zone (WQSZ), point to a higher frequency of earthquakes and slope failure during deglaciation and rapid glacio-isostatic rebound though faulting continues into the postglacial. Lateglacial faulting, diapiric deformation and slumping of coeval lateglacial sediments is observed in Parry Sound, Lake Muskoka and Lake Joseph, which are all located above prominent Precambrian terrane boundaries. Lateglacial sediments are sharply overlain by relatively-thin rhythmically-laminated and often semi

Whiting in Lake Michigan

Science.gov (United States)

2002-01-01

Satellites provide a view from space of changes on the Earth's surface. This series of images from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) aboard the Orbview-2 satellite shows the dramatic change in the color of Lake Michigan during the summer. The bright color that appears in late summer is probably caused by calcium carbonate-chalk-in the water. Lake Michigan always has a lot of calcium carbonate in it because the floor of the lake is limestone. During most of the year the calcium carbonate remains dissolved in the cold water, but at the end of summer the lake warms up, lowering the solubility of calcium carbonate. As a result, the calcium carbonate precipitates out of the water, forming clouds of very small solid particles that appear as bright swirls from above. The phenomenon is appropriately called a whiting event. A similar event occured in 1999, but appears to have started later and subsided earlier. It is also possible that a bloom of the algae Microcystis is responsible for the color change, but unlikely because of Lake Michigan's depth and size. Microcystis blooms have occured in other lakes in the region, however. On the shore of the lake it is possible to see the cities of Chicago, Illinois, and Milwaukee, Wisconsin. Both appear as clusters of gray-brown pixels. Image courtesy the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

Lake-0: A model for the simulation of nuclides transfer in lake scenarios

International Nuclear Information System (INIS)

Garcia-Olivares, A.; Aguero, A.; Pinedo, P.

1994-01-01

This report presents documentation and a user's manual for the program LAKE-0, a mathematical model of nuclides transfer in lake scenarios. Mathematical equations and physical principles used to develop the code are presented in section 2. The program use is presented in section 3 including input data sets and output data. Section 4 presents two example problems, and some results. The complete program listing including comments is presented in Appendix A. Nuclides are assumed to enter the lake via atmospheric deposition and carried by the water runoff and the dragged sediments from the adjacent catchment. The dynamics of the nuclides inside the lake is based in the model proposed by Codell (11) as modified in (5). The removal of concentration from the lake water is due to outflow from the lake and to the transfer of activity to the bottom sediments. The model has been applied to the Esthwaite Water (54 degree 21 minute N, 03 degree 00 minute W at 65 m. asl.) in the frame of the VAMP Aquatic Working Group (8) and to Devoke Water (54 degree 21 minute 5'N, 03 degree, 18 minute W at 230 m. asl.)

LAKE-0: a model for the simulation of nuclides transfer in lake scenarios

International Nuclear Information System (INIS)

Garcia-Olivares, A.; Aguero, A.; Pinedo, P.

1994-01-01

This report presents documentation and a user's manual for the program LAKE-0, a mathematical model of nuclides transfer in lake scenarios. Mathematical equations and physical principles used to develop the code are presented in section 2. The program use is presented in section 3 including input data sets and output data. Section 4 presents two example problems, and some results. The complete program listing including comments is presented in Appendix A. Nuclides are assumed to center the lake via atmospheric deposition and carried by the water runoff and the dragged sediments from the adjacent catchment. The dynamics of the nuclides inside the lake is based in the model proposed by Codell (11) as modified in (5). The removal of concentration from the lake water is due to out flow from the lake and to the transfer of activity to the button sediments. The model has been applied to the Esthwaite Water (54 degree celsius 2 l'N, 03 degree celsius 00'W at 65 m. asi.) in the frame of the VAMP Aquatic Working Group (8) and to Devoke Water (5 21.5'N, 03H8'W at 230 m. asi.). (Author). 13 refs

Development and evaluation of the Lake Multi-biotic Integrity Index for Dongting Lake, China

Directory of Open Access Journals (Sweden)

Xing Wang

2015-06-01

Full Text Available A Lake Multi-biotic Integrity Index (LMII for the China’s second largest interior lake (Dongting Lake was developed to assess the water quality status using algal and macroinvertebrate metrics. Algae and benthic macroinvertebrate assemblages were sampled at 10 sections across 3 subregions of Dongting Lake. We used a stepwise process to evaluate properties of candidate metrics and selected ten for the LMII: Pampean diatom index, diatom quotient, trophic diatom index, relative abundance diatoms, Margalef index of algae, percent sensitive diatoms, % facultative individuals, % Chironomidae individuals, % predators individuals, and total number of macroinvertebrate taxa. We then tested the accuracy and feasibility of the LMII by comparing the correlation with physical-chemical parameters. Evaluation of the LMII showed that it discriminated well between reference and impaired sections and was strongly related to the major chemical and physical stressors (r = 0.766, P<0.001. The re-scored results from the 10 sections showed that the water quality of western Dongting Lake was good, while that of southern Dongting Lake was relatively good and whereas that of eastern Dongting Lake was poor. The discriminatory biocriteria of the LMII are suitable for the assessment of the water quality of Dongting Lake. Additionally, more metrics belonging to habitat, hydrology, physics and chemistry should be considered into the LMII, so as to establish comprehensive assessment system which can reflect the community structure of aquatic organisms, physical and chemical characteristics of water environment, human activities, and so on.

O método da falsa posição na história e na educação matemática The false position method in history and in mathematics education

Directory of Open Access Journals (Sweden)

Cleide Farias de Medeiros

2004-12-01

Full Text Available Este texto coloca em uma perspectiva histórica o tratamento algébrico precoce que, costumeiramente, é dedicado ao ensino elementar da Aritmética. Defendendo que um tal tratamento algébrico precoce carrega vários pontos negativos para a formação do educando, o texto discute o "método da falsa posição" como uma alternativa viável para um tal ensino introdutório. Apontando as raízes históricas de tal método, o texto procura evidenciar as origens, aplicações e várias formas de visualizar este procedimento iterativo, desde a manipulação de materiais concretos, passando por aplicações geométricas, até atingir o Cálculo Numérico, como um dos procedimentos iterativos na resolução de equações lineares. Uma das conclusões é que, embora não seja o referido método, em sua forma mais simples, nenhum substitutivo para a resolução algébrica simbólica e moderna de equações e de sistemas de equações, ele se constitui certamente em um precioso trampolim para iniciarmos o salto em direção a um estudo mais formalizado. Particularmente, o método da falsa posição revela-se uma utilíssima ferramenta pedagógica na Educação Matemática, principalmente quando vinculado às suas origens históricas, suas abordagens concretas iniciais e suas associações com a Geometria e a Geometria Analítica.This text is a historical perspective on the early algebraic approach that is usually applied to the elementary teaching of Arithmetic. By arguing that such an initial algebraic treatment contains several drawbacks for elementary education, the ‘false position method' is discussed and is presented as a viable alternative for such introductory teaching. By pointing out the historical roots of the method, the text tries to make clear several ways of visualising this iterative procedure. This is done by incorporating the use of manipulatives and geometrical applications as well as the use of numerical calculus as an iterative

Comparing Effects of Lake- and Watershed-Scale Influences on Communities of Aquatic Invertebrates in Shallow Lakes

Science.gov (United States)

Hanson, Mark A.; Herwig, Brian R.; Zimmer, Kyle D.; Fieberg, John; Vaughn, Sean R.; Wright, Robert G.; Younk, Jerry A.

2012-01-01

Constraints on lake communities are complex and are usually studied by using limited combinations of variables derived from measurements within or adjacent to study waters. While informative, results often provide limited insight about magnitude of simultaneous influences operating at multiple scales, such as lake- vs. watershed-scale. To formulate comparisons of such contrasting influences, we explored factors controlling the abundance of predominant aquatic invertebrates in 75 shallow lakes in western Minnesota, USA. Using robust regression techniques, we modeled relative abundance of Amphipoda, small and large cladocera, Corixidae, aquatic Diptera, and an aggregate taxon that combined Ephemeroptera-Trichoptera-Odonata (ETO) in response to lake- and watershed-scale characteristics. Predictor variables included fish and submerged plant abundance, linear distance to the nearest wetland or lake, watershed size, and proportion of the watershed in agricultural production. Among-lake variability in invertebrate abundance was more often explained by lake-scale predictors than by variables based on watershed characteristics. For example, we identified significant associations between fish presence and community type and abundance of small and large cladocera, Amphipoda, Diptera, and ETO. Abundance of Amphipoda, Diptera, and Corixidae were also positively correlated with submerged plant abundance. We observed no associations between lake-watershed variables and abundance of our invertebrate taxa. Broadly, our results seem to indicate preeminence of lake-level influences on aquatic invertebrates in shallow lakes, but historical land-use legacies may mask important relationships. PMID:22970275

Eutrophication potential of Payette Lake, Idaho

Science.gov (United States)

Woods, Paul F.

1997-01-01

Payette Lake was studied during water years 1995-96 to determine the 20.5-square-kilometer lake's assimilative capacity for nutrients and, thus, its eutrophication potential. The study included quantification of hydrologic and nutrient budgets, characterization of water quality in the limnetic and littoral zones, development of an empirical nutrient load/lake response model, and estimation of the limnological effects of a large-scale forest fire in the lake's 373-square-kilometer watershed during the autumn of 1994. Streamflow from the North Fork Payette River, the lake's primary tributary, delivered about 73 percent of the lake's inflow over the 2 years. Outflow from the lake, measured since 1908, was 128 and 148 percent of the long-term average in 1995 and 1996, respectively. The larger volumes of outflow reduced the long-term average water-

Microplastics in Taihu Lake, China.

Science.gov (United States)

Su, Lei; Xue, Yingang; Li, Lingyun; Yang, Dongqi; Kolandhasamy, Prabhu; Li, Daoji; Shi, Huahong

2016-09-01

In comparison with marine environments, the occurrence of microplastics in freshwater environments is less understood. In the present study, we investigated microplastic pollution levels during 2015 in Taihu Lake, the third largest Chinese lake located in one of the most developed areas of China. The abundance of microplastics reached 0.01 × 10(6)-6.8 × 10(6) items/km(2) in plankton net samples, 3.4-25.8 items/L in surface water, 11.0-234.6 items/kg dw in sediments and 0.2-12.5 items/g ww in Asian clams (Corbicula fluminea). The average abundance of microplastics was the highest in plankton net samples from the southeast area of the lake and in the sediments from the northwest area of the lake. The northwest area of the lake was the most heavily contaminated area of the lake, as indicated by chlorophyll-α and total phosphorus. The microplastics were dominated by fiber, 100-1000 μm in size and cellophane in composition. To our best knowledge, the microplastic levels measured in plankton net samples collected from Taihu Lake were the highest found in freshwater lakes worldwide. The ratio of the microplastics in clams to each sediment sample ranged from 38 to 3810 and was negatively correlated to the microplastic level in sediments. In brief, our results strongly suggest that high levels of microplastics occurred not only in water but also in organisms in Taihu Lake. Copyright © 2016 Elsevier Ltd. All rights reserved.

From top to bottom: Do Lake Trout diversify along a depth gradient in Great Bear Lake, NT, Canada?

Science.gov (United States)

Chavarie, Louise; Howland, Kimberly L; Harris, Les N; Hansen, Michael J; Harford, William J; Gallagher, Colin P; Baillie, Shauna M; Malley, Brendan; Tonn, William M; Muir, Andrew M; Krueger, Charles C

2018-01-01

Depth is usually considered the main driver of Lake Trout intraspecific diversity across lakes in North America. Given that Great Bear Lake is one of the largest and deepest freshwater systems in North America, we predicted that Lake Trout intraspecific diversity to be organized along a depth axis within this system. Thus, we investigated whether a deep-water morph of Lake Trout co-existed with four shallow-water morphs previously described in Great Bear Lake. Morphology, neutral genetic variation, isotopic niches, and life-history traits of Lake Trout across depths (0-150 m) were compared among morphs. Due to the propensity of Lake Trout with high levels of morphological diversity to occupy multiple habitat niches, a novel multivariate grouping method using a suite of composite variables was applied in addition to two other commonly used grouping methods to classify individuals. Depth alone did not explain Lake Trout diversity in Great Bear Lake; a distinct fifth deep-water morph was not found. Rather, Lake Trout diversity followed an ecological continuum, with some evidence for adaptation to local conditions in deep-water habitat. Overall, trout caught from deep-water showed low levels of genetic and phenotypic differentiation from shallow-water trout, and displayed higher lipid content (C:N ratio) and occupied a higher trophic level that suggested an potential increase of piscivory (including cannibalism) than the previously described four morphs. Why phenotypic divergence between shallow- and deep-water Lake Trout was low is unknown, especially when the potential for phenotypic variation should be high in deep and large Great Bear Lake. Given that variation in complexity of freshwater environments has dramatic consequences for divergence, variation in the complexity in Great Bear Lake (i.e., shallow being more complex than deep), may explain the observed dichotomy in the expression of intraspecific phenotypic diversity between shallow- vs. deep-water habitats

From top to bottom: Do Lake Trout diversify along a depth gradient in Great Bear Lake, NT, Canada?

Science.gov (United States)

Chavarie, Louise; Howland, Kimberly L.; Harris, Les N.; Hansen, Michael J.; Harford, William J.; Gallagher, Colin P.; Baillie, Shauna M.; Malley, Brendan; Tonn, William M.; Muir, Andrew M.; Krueger, Charles C.

2018-01-01

Depth is usually considered the main driver of Lake Trout intraspecific diversity across lakes in North America. Given that Great Bear Lake is one of the largest and deepest freshwater systems in North America, we predicted that Lake Trout intraspecific diversity to be organized along a depth axis within this system. Thus, we investigated whether a deep-water morph of Lake Trout co-existed with four shallow-water morphs previously described in Great Bear Lake. Morphology, neutral genetic variation, isotopic niches, and life-history traits of Lake Trout across depths (0–150 m) were compared among morphs. Due to the propensity of Lake Trout with high levels of morphological diversity to occupy multiple habitat niches, a novel multivariate grouping method using a suite of composite variables was applied in addition to two other commonly used grouping methods to classify individuals. Depth alone did not explain Lake Trout diversity in Great Bear Lake; a distinct fifth deep-water morph was not found. Rather, Lake Trout diversity followed an ecological continuum, with some evidence for adaptation to local conditions in deep-water habitat. Overall, trout caught from deep-water showed low levels of genetic and phenotypic differentiation from shallow-water trout, and displayed higher lipid content (C:N ratio) and occupied a higher trophic level that suggested an potential increase of piscivory (including cannibalism) than the previously described four morphs. Why phenotypic divergence between shallow- and deep-water Lake Trout was low is unknown, especially when the potential for phenotypic variation should be high in deep and large Great Bear Lake. Given that variation in complexity of freshwater environments has dramatic consequences for divergence, variation in the complexity in Great Bear Lake (i.e., shallow being more complex than deep), may explain the observed dichotomy in the expression of intraspecific phenotypic diversity between shallow- vs. deep-water habitats

Predicting Maximum Lake Depth from Surrounding Topography

Science.gov (United States)

Lake volume aids understanding of the physical and ecological dynamics of lakes, yet is often not readily available. The data needed to calculate lake volume (i.e. bathymetry) are usually only collected on a lake by lake basis and are difficult to obtain across broad regions. ...

Reconstructing Heat Fluxes Over Lake Erie During the Lake Effect Snow Event of November 2014

Science.gov (United States)

Fitzpatrick, L.; Fujisaki-Manome, A.; Gronewold, A.; Anderson, E. J.; Spence, C.; Chen, J.; Shao, C.; Posselt, D. J.; Wright, D. M.; Lofgren, B. M.; Schwab, D. J.

2017-12-01

The extreme North American winter storm of November 2014 triggered a record lake effect snowfall (LES) event in southwest New York. This study examined the evaporation from Lake Erie during the record lake effect snowfall event, November 17th-20th, 2014, by reconstructing heat fluxes and evaporation rates over Lake Erie using the unstructured grid, Finite-Volume Community Ocean Model (FVCOM). Nine different model runs were conducted using combinations of three different flux algorithms: the Met Flux Algorithm (COARE), a method routinely used at NOAA's Great Lakes Environmental Research Laboratory (SOLAR), and the Los Alamos Sea Ice Model (CICE); and three different meteorological forcings: the Climate Forecast System version 2 Operational Analysis (CFSv2), Interpolated observations (Interp), and the High Resolution Rapid Refresh (HRRR). A few non-FVCOM model outputs were also included in the evaporation analysis from an atmospheric reanalysis (CFSv2) and the large lake thermodynamic model (LLTM). Model-simulated water temperature and meteorological forcing data (wind direction and air temperature) were validated with buoy data at three locations in Lake Erie. The simulated sensible and latent heat fluxes were validated with the eddy covariance measurements at two offshore sites; Long Point Lighthouse in north central Lake Erie and Toledo water crib intake in western Lake Erie. The evaluation showed a significant increase in heat fluxes over three days, with the peak on the 18th of November. Snow water equivalent data from the National Snow Analyses at the National Operational Hydrologic Remote Sensing Center showed a spike in water content on the 20th of November, two days after the peak heat fluxes. The ensemble runs presented a variation in spatial pattern of evaporation, lake-wide average evaporation, and resulting cooling of the lake. Overall, the evaporation tended to be larger in deep water than shallow water near the shore. The lake-wide average evaporations

Hydrologic-energy balance constraints on the Holocene lake-level history of lake Titicaca, South America

Energy Technology Data Exchange (ETDEWEB)

Rowe, H.D.; Dunbar, R.B. [Stanford University, Geological and Environmental Sciences, Stanford, CA (United States)

2004-09-01

A basin-scale hydrologic-energy balance model that integrates modern climatological, hydrological, and hypsographic observations was developed for the modern Lake Titicaca watershed (northern Altiplano, South America) and operated under variable conditions to understand controls on post-glacial changes in lake level. The model simulates changes in five environmental variables (air temperature, cloud fraction, precipitation, relative humidity, and land surface albedo). Relatively small changes in three meteorological variables (mean annual precipitation, temperature, and/or cloud fraction) explain the large mid-Holocene lake-level decrease ({proportional_to}85 m) inferred from seismic reflection profiling and supported by sediment-based paleoproxies from lake sediments. Climatic controls that shape the present-day Altiplano and the sediment-based record of Holocene lake-level change are combined to interpret model-derived lake-level simulations in terms of changes in the mean state of ENSO and its impact on moisture transport to the Altiplano. (orig.)

Hydrologic-energy balance constraints on the Holocene lake-level history of lake Titicaca, South America

Science.gov (United States)

Rowe, H. D.; Dunbar, R. B.

2004-09-01

A basin-scale hydrologic-energy balance model that integrates modern climatological, hydrological, and hypsographic observations was developed for the modern Lake Titicaca watershed (northern Altiplano, South America) and operated under variable conditions to understand controls on post-glacial changes in lake level. The model simulates changes in five environmental variables (air temperature, cloud fraction, precipitation, relative humidity, and land surface albedo). Relatively small changes in three meteorological variables (mean annual precipitation, temperature, and/or cloud fraction) explain the large mid-Holocene lake-level decrease (˜85 m) inferred from seismic reflection profiling and supported by sediment-based paleoproxies from lake sediments. Climatic controls that shape the present-day Altiplano and the sediment-based record of Holocene lake-level change are combined to interpret model-derived lake-level simulations in terms of changes in the mean state of ENSO and its impact on moisture transport to the Altiplano.

In-Lake Processes Offset Increased Terrestrial Inputs of Dissolved Organic Carbon and Color to Lakes

Science.gov (United States)

Köhler, Stephan J.; Kothawala, Dolly; Futter, Martyn N.; Liungman, Olof; Tranvik, Lars

2013-01-01

Increased color in surface waters, or browning, can alter lake ecological function, lake thermal stratification and pose difficulties for drinking water treatment. Mechanisms suggested to cause browning include increased dissolved organic carbon (DOC) and iron concentrations, as well as a shift to more colored DOC. While browning of surface waters is widespread and well documented, little is known about why some lakes resist it. Here, we present a comprehensive study of Mälaren, the third largest lake in Sweden. In Mälaren, the vast majority of water and DOC enters a western lake basin, and after approximately 2.8 years, drains from an eastern basin. Despite 40 years of increased terrestrial inputs of colored substances to western lake basins, the eastern basin has resisted browning over this time period. Here we find the half-life of iron was far shorter (0.6 years) than colored organic matter (A420 ; 1.7 years) and DOC as a whole (6.1 years). We found changes in filtered iron concentrations relate strongly to the observed loss of color in the western basins. In addition, we observed a substantial shift from colored DOC of terrestrial origin, to less colored autochthonous sources, with a substantial decrease in aromaticity (-17%) across the lake. We suggest that rapid losses of iron and colored DOC caused the limited browning observed in eastern lake basins. Across a wider dataset of 69 Swedish lakes, we observed greatest browning in acidic lakes with shorter retention times (< 1.5 years). These findings suggest that water residence time, along with iron, pH and colored DOC may be of central importance when modeling and projecting changes in brownification on broader spatial scales. PMID:23976946

Visual observations of historical lake trout spawning grounds in western Lake Huron

Science.gov (United States)

Nester, Robert T.; Poe, Thomas P.

1987-01-01

Direct underwater video observations were made of the bottom substrates at 12 spawning grounds formerly used by lake trout Salvelinus namaycush in western Lake Huron to evaluate their present suitability for successful reproduction by lake trout. Nine locations examined north of Saginaw Bay in the northwestern end of the lake are thought to provide the best spawning habitat. The substrate at these sites consisted of angular rough cobble and rubble with relatively deep interstitial spaces (a?Y 0.5 m), small amounts of fine sediments, and little or no periphytic growth. Conditions at the three other sampling locations south of Saginaw Bay seemed much less suitable for successful reproduction based on the reduced area of high-quality substrate, shallow interstitial spaces, high infiltration of fine sediments, and greater periphytic growth.

Evaluation of ground-water flow and hydrologic budget for Lake Five-O, a seepage lake in northwestern Florida

Science.gov (United States)

Grubbs, J.W.

1995-01-01

Temporal and spatial distributions of ground-water inflow to, and leakage from Lake Five-O, a softwater, seepage lake in northwestern Florida, were evaluated using hydrologic data and simulation models of the shallow ground-water system adjacent to the lake. The simulation models indicate that ground-water inflow to the lake and leakage from the lake to the ground-water system are the dominant components in the total inflow (precipitation plus ground-water inflow) and total outflow (evaporation plus leakage) budgets of Lake Five-O. Simlulated ground-water inflow and leakage were approximately 4 and 5 times larger than precipitation inputs and evaporative losses, respectively, during calendar years 1989-90. Exchanges of water between Lake Five-O and the ground-water system were consistently larger than atmospheric-lake exchanges. A consistent pattern of shallow ground-water inflow and deep leakage was also evident throughout the study period. The mean time of travel from ground-water that discharges at Lake Five-O (time from recharge at the water table to discharge at the lake) was estimated to be within a range of 3 to 6 years. Flow-path evaluations indicated that the intermediate confining unit probably has a negligible influence on the geochemistry of ground-water inflow to Lake Five-O. The hydrologic budgets and flow-path evaluations provide critical information for developing geochemical budgets for Lake Five-O and for improving the understanding of the relative importance of various processes that regulate the acid-neutralizing capacity of softwater seepage lakes in Florida.

Great Lakes Science Center

Data.gov (United States)

Federal Laboratory Consortium — Since 1927, Great Lakes Science Center (GLSC) research has provided critical information for the sound management of Great Lakes fish populations and other important...

Changes in the dreissenid community in the lower Great Lakes with emphasis on southern Lake Ontario

Science.gov (United States)

Mills, Edward L.; Chrisman, Jana R.; Baldwin, Brad; Owens, Randall W.; O'Gorman, Robert; Howell, Todd; Roseman, Edward F.; Raths, Melinda K.

1999-01-01

A field study was conducted in the lower Great Lakes to assess changes in spatial distribution and population structure of dreissenid mussel populations. More specifically, the westward range expansion of quagga mussel into western Lake Erie and toward Lake Huron was investigated and the shell size, density, and biomass of zebra and quagga mussel with depth in southern Lake Ontario in 1992 and 1995 were compared. In Lake Erie, quagga mussel dominated the dreissenid community in the eastern basin and zebra mussel dominated in the western basin. In southern Lake Ontario, an east to west gradient was observed with the quagga mussel dominant at western sites and zebra mussel dominant at eastern locations. Mean shell size of quagga mussel was generally larger than that of zebra mussel except in western Lake Erie and one site in eastern Lake Erie. Although mean shell size and our index of numbers and biomass of both dreissenid species increased sharply in southern Lake Ontario between 1992 and 1995, the increase in density and biomass was much greater for quagga mussels over the 3-year period. In 1995, zebra mussels were most abundant at 15 to 25 m whereas the highest numbers and biomass of quagga mussel were at 35 to 45 m. The quagga mussel is now the most abundant dreissenid in areas of southern Lake Ontario where the zebra mussel was once the most abundant dreissenid; this trend parallels that observed for dreissenid populations in the Dneiper River basin in the Ukraine.

Egg fatty acid composition from lake trout fed two Lake Michigan prey fish species.

Science.gov (United States)

Honeyfield, D.C.; Fitzsimons, J.D.; Tillitt, D.E.; Brown, S.B.

2009-01-01

We previously demonstrated that there were significant differences in the egg thiamine content in lake trout Salvelinus namaycush fed two Lake Michigan prey fish (alewife Alosa pseudoharengus and bloater Coregonus hoyi). Lake trout fed alewives produced eggs low in thiamine, but it was unknown whether the consumption of alewives affected other nutritionally important components. In this study we investigated the fatty acid composition of lake trout eggs when females were fed diets that resulted in different egg thiamine concentrations. For 2 years, adult lake trout were fed diets consisting of four combinations of captured alewives and bloaters (100% alewives; 65% alewives, 35% bloaters; 35% alewives, 65% bloaters; and 100% bloaters). The alewife fatty acid profile had higher concentrations of arachidonic acid and total omega-6 fatty acids than the bloater profile. The concentrations of four fatty acids (cis-13, 16-docosadienoic, eicosapentaenoic, docosapentaenoic, and docosahexaenoic acids) were higher in bloaters than in alewives. Although six fatty acid components were higher in lake trout eggs in 2001 than in 2000 and eight fatty acids were lower, diet had no effect on any fatty acid concentration measured in lake trout eggs in this study. Based on these results, it appears that egg fatty acid concentrations differ between years but that the egg fatty acid profile does not reflect the alewife-bloater mix in the diet of adults. The essential fatty acid content of lake trout eggs from females fed alewives and bloaters appears to be physiologically regulated and adequate to meet the requirements of developing embryos.

Evaporation variability of Nam Co Lake in the Tibetan Plateau and its role in recent rapid lake expansion

Science.gov (United States)

Ma, Ning; Szilagyi, Jozsef; Niu, Guo-Yue; Zhang, Yinsheng; Zhang, Teng; Wang, Binbin; Wu, Yanhong

2016-06-01

Previous studies have shown that the majority of the lakes in the Tibetan Plateau (TP) started to expand rapidly since the late 1990s. However, the causes are still not well known. For Nam Co, being a closed lake with no outflow, evaporation (EL) over the lake surface is the only way water may leave the lake. Therefore, quantifying EL is key for investigating the mechanism of lake expansion in the TP. EL can be quantified by Penman- and/or bulk-transfer-type models, requiring only net radiation, temperature, humidity and wind speed for inputs. However, interpolation of wind speed data may be laden with great uncertainty due to extremely sparse ground meteorological observations, the highly heterogeneous landscape and lake-land breeze effects. Here, evaporation of Nam Co Lake was investigated within the 1979-2012 period at a monthly time-scale using the complementary relationship lake evaporation (CRLE) model which does not require wind speed data. Validations by in-situ observations of E601B pan evaporation rates at the shore of Nam Co Lake as well as measured EL over an adjacent small lake using eddy covariance technique suggest that CRLE is capable of simulating EL well since it implicitly considers wind effects on evaporation via its vapor transfer coefficient. The multi-year average of annual evaporation of Nam Co Lake is 635 mm. From 1979 to 2012, annual evaporation of Nam Co Lake expressed a very slight decreasing trend. However, a more significant decrease in EL occurred during 1998-2008 at a rate of -12 mm yr-1. Based on water-level readings, this significant decrease in lake evaporation was found to be responsible for approximately 4% of the reported rapid water level increase and areal expansion of Nam Co Lake during the same period.

The influence of carbon exchange of a large lake on regional tracer-transport inversions: results from Lake Superior

International Nuclear Information System (INIS)

Vasys, Victoria N; Desai, Ankur R; McKinley, Galen A; Bennington, Val; Michalak, Anna M; Andrews, Arlyn E

2011-01-01

Large lakes may constitute a significant component of regional surface-atmosphere fluxes, but few efforts have been made to quantify these fluxes. Tracer-transport inverse models that infer the CO 2 flux from the atmospheric concentration typically assume that the influence from large lakes is negligible. CO 2 observations from a tall tower in Wisconsin segregated by wind direction suggested a CO 2 signature from Lake Superior. To further investigate this difference, source-receptor influence functions derived using a mesoscale transport model were applied and results revealed that air masses sampled by the tower have a transit time over the lake, primarily in winter when the total lake influence on the tower can exceed 20% of the total influence of the regional domain. When the influence functions were convolved with air-lake fluxes estimated from a physical-biogeochemical lake model, the overall total contribution of lake fluxes to the tall tower CO 2 were mostly negligible, but potentially detectable in certain periods of fall and winter when lake carbon exchange can be strong and land carbon efflux weak. These findings suggest that large oligotrophic lakes would not significantly influence inverse models that incorporate tall tower CO 2 .

Submerged Grove in Lake Onogawa

OpenAIRE

Sato, Yasuhiro; Nakamura, Soken; Ochiai, Masahiro

1996-01-01

Abstract : The first record by ultrasonic echo sounding on the distribution of the submerged standing trees on the bottom of Lake Onogawa is presented. Lake Onogawa is a dammed lake formed at the time of the eruption of the volcano Mt.Bandai in 1888. Since then the original vegetation of the dammed valley has remained submerged. Many submerged standing trees are distributed on the bottom within about 600m from the northeast end of the lake. The density of the trees in this area is sufficient ...

L-Lake zooplankton: L-Lake/Steel Creek Biological Monitoring Program, November 1985--December 1991

Energy Technology Data Exchange (ETDEWEB)

Bowers, J.A. [Westinghouse Savannah River Co., Aiken, SC (United States); Bowen, M. [Normandeau Associates, Inc., New Ellenton, SC (United States)

1992-03-01

The L- Lake Biological Monitoring Program was designed to meet environmental regulatory requirements associated with the restart of L-Reactor and address portions of Section 316(a) of the Clean Water Act, which requires an applicant for a discharge permit to provide scientific evidence that the discharge causes no significant impact on the indigenous ecosystem. The Department of Energy (DOE) must demonstrate that the discharge of L-Reactor affluent into L Lake will not inhibit the eventual establishment of a ``Balanced Biological Community`` (BBC) in at least 50% of the lake. This report details results of monitoring zooplankton populations in L-Lake.

L-Lake zooplankton: L-Lake/Steel Creek Biological Monitoring Program, November 1985--December 1991

International Nuclear Information System (INIS)

Bowers, J.A.; Bowen, M.

1992-03-01

The L- Lake Biological Monitoring Program was designed to meet environmental regulatory requirements associated with the restart of L-Reactor and address portions of Section 316(a) of the Clean Water Act, which requires an applicant for a discharge permit to provide scientific evidence that the discharge causes no significant impact on the indigenous ecosystem. The Department of Energy (DOE) must demonstrate that the discharge of L-Reactor affluent into L Lake will not inhibit the eventual establishment of a ''Balanced Biological Community'' (BBC) in at least 50% of the lake. This report details results of monitoring zooplankton populations in L-Lake

LAKE-0: a model for the simulation of nuclides transfer in lake scenarios

Energy Technology Data Exchange (ETDEWEB)

Garcia-Olivares, A.; Aguero, A.; Pinedo, P.

1994-07-01

This report presents documentation and a user's manual for the program LAKE-0, a mathematical model of nuclides transfer in lake scenarios. Mathematical equations and physical principles used to develop the code are presented in section 2. The program use is presented in section 3 including input data sets and output data. Section 4 presents two example problems, and some results. The complete program listing including comments is presented in Appendix A. Nuclides are assumed to center the lake via atmospheric deposition and carried by the water runoff and the dragged sediments from the adjacent catchment. The dynamics of the nuclides inside the lake is based in the model proposed by Codell (11) as modified in (5). The removal of concentration from the lake water is due to out flow from the lake and to the transfer of activity to the button sediments. The model has been applied to the Esthwaite Water (54 degree celsius 2 l'N, 03 degree celsius 00'W at 65 m. asi.) in the frame of the VAMP Aquatic Working Group (8) and to Devoke Water (5 21.5'N, 03H8'W at 230 m. asi.). (Author). 13 refs.

Sistemas de identificación por radiofrecuencia, código de barras y su relación con la gestión de la cadena de suministro

Directory of Open Access Journals (Sweden)

Alexander Correa Espinal

2010-07-01

Full Text Available El articulo muestra, a través del análisis de libros, artículos científicos y algunos estudios existentes, el estado del arte y la relación entre los sistemas de identificación (código de barras y radiofrecuencia y la gestión de la cadena de suministro, en aplicaciones significativas a nivel mundial y de Colombia. Para ello, se compilan conceptos generales de los sistemas de identificación presentando sus definiciones, componentes de hardware/software, aplicaciones en la cadena de suministro y el uso que grandes, medianas y pequeñas empresas le otorgan. El estudio pone en evidencia la importancia que estas tecnologías tienen para mejorar el desempeño y la trazabilidad, simplificar operaciones, reducir costos y agilizar los flujos de información en la cadena de suministro.

Isotope techniques in lake water studies

International Nuclear Information System (INIS)

Gourcy, L.

1999-01-01

Freshwater lakes are among the most easily exploitable freshwater resources. Lakes are also recognized as major sedimentological features in which stored material can be used to study recent climate and pollution evolution. To adequately preserve these important landscape features, and to use them as climatic archives, an improved understanding of processes controlling their hydrologic and bio-geochemical environments if necessary. This article briefly describes the IAEA activities related to the study of lakes in such areas as lake budget, lake dynamics, water contamination, and paleolimnological investigations

Lake Erie and Lake Michigan zebra mussel settlement monitoring and implications for chlorination treatment

International Nuclear Information System (INIS)

Demoss, D.; Mendelsberg, J.I.

1992-01-01

This paper reports on the 1991 zebra mussel veliger settlement monitoring program undertaken to record and evaluate zebra mussel veliger settlement in Lake Erie and Lake Michigan. Studies by Dr. Gerald Mackie of Canada in 1990 indicated veliger settlement may be occurring primarily during short time periods every season corresponding with warmer water temperatures. Veliger settlement monitoring was performed using a plexiglass sampler apparatus. The samplers were simple in design and consisted of a 20-inch-square plexiglass base panel with thirty-six 1 inch x 3 inch clear plexiglass microscope slides attached. The results of the monitoring program indicate the existence of preferential settlement periods for veligers correlating with sustained lake water temperatures above 70 degrees F. Veliger settlement concentrations in the south basin of Lake Michigan appear to be similar to those in western Lake Erie

Lake or Pond WBID

Data.gov (United States)

Vermont Center for Geographic Information — The VT DEC (Vermont Department of Environmental Conservation) manages an inventory of lake and pond information. The "Lakes and Ponds Inventory" stores the Water...

The reproduction of lake trout in southern Lake Superior

Science.gov (United States)

Eschmeyer, Paul H.

1955-01-01

The principal spawning grounds of lake trout (Salvelinus namaycush namaycush) in United States waters of southern Lake Superior are on rocky shoals at depths of less than 20 fathoms. Most spawning occurs in October and early November. Of the mature fish collected on or near the spawning grounds, 60 to 69 percent were males. Among mature fish the average length of females was greater than that of males; few males less than 24 inches or females less than 26 inches in total length were caught. Recoveries of lake trout tagged on the spawning grounds showed that some males remained in the immediate area for a period of several weeks during the spawning season. Marked fish showed a tendency to return during later years to spawning grounds on which they had been tagged, even though many of them ranged long distances between spawning seasons.

DNR 24K Lakes

Data.gov (United States)

Minnesota Department of Natural Resources — Medium scale lake polygons derived from the National Wetlands Inventory (NWI) polygons and MnDOT Basemap lake delineations. Integrated with the DNR 24K Streams...

Crustacean plankton communities in forty-five lakes in the experimental lakes area, northwestern Ontario

Energy Technology Data Exchange (ETDEWEB)

Patalas, K

1971-01-01

Zooplankton communities were characterized on the basis of samples taken in summer as vertical net hauls in the central part of lakes. Twenty-eight species of crustaceans were found in the 45 lakes studied. The highest number of species as well as the highest numbers of individuals (per unit of area) usually occurred in the largest deepest lakes with most transparent water.

Cognição social em crianças: descobrindo a influência de crenças falsas e emoções no comportamento humano Social cognition on children: discovering the influence of false beliefs and emotions on human behavior

Directory of Open Access Journals (Sweden)

Suely de Melo Santana

2006-01-01

Full Text Available O estudo investigou a compreensão das crianças sobre a influência de crenças e emoções no comportamento. Participaram 100 crianças de 4-5 anos, diferentes níveis socioeconômicos, ambos sexos, distribuídas em 04 grupos conforme a idade. Apresentou-se uma transferência inesperada de objeto, seguida de duas questões em condições distintas. Observou-se a teoria da mente em 56% delas, a partir dos 4 anos. A análise loglinear mostrou que fatores como idade e nível socioeconômico são preditores significativos de melhor desempenho. Comparando-se os resultados nas questões de crença falsa e emoção, foi observada melhora crescente conforme a idade, tendo a questão de emoção apresentado padrão mais elevado. Discutiu-se: 1 a capacidade em predizer e justificar emoções desenvolve-se mais cedo que a habilidade para inferir ações baseadas em crença falsa; 2 o modo de apresentação da questão não favorece o desempenho; e 3 a interferência do nível socioeconômico ocorre entre os 54-65 meses de idade.The study had investigated the children's comprehension of the influence of beliefs and emotions on human behavior. Participated 100 children, from 4 and 5 years old, different socioeconomic levels, both genders, distributed in 4 groups according to the age in months. The results was an unexpected object transference, followed by two questions in different conditions. Observed the theory of mind occurs in 56% of the them, starting at 4 years old. The loglinear analysis showed that the factors age and socioeconomic level are meaningful predictors of a better performance. Comparing the results in the questions of false belief and emotion, it was observed an increasing improvement in the development according to age, but in the question of emotion it showed a higher standard. It is discussed: (1 the capacity in predicting and justifying emotions is developed earlier than the ability to infer actions based upon false belief, (2 the

Análisis de la resistencia a la corrosión de barras corrugadas de acero inoxidable en medios acuosos que simulan el hormigón

Directory of Open Access Journals (Sweden)

Belzunce, F. J.

2004-04-01

Full Text Available The corrosion behaviour of stainless steel reinforced bars used in civil engineering was studied. Different electrochemical tests were performed using several stainless steel bars (austenitic and duplex, hot and cold rolled, in the presence of a solution, which simulates the contact with salt contaminated concrete. The corrosion rates were determined and also their behaviour against localized corrosion (pitting.

Se ha realizado un estudio sobre la resistencia a la corrosión de barras corrugadas de acero inoxidable utilizadas en construcción civil para armar el hormigón. Con este objeto se han realizado diferentes ensayos electroquímicos en presencia de un medio acuoso básico, que simula el contacto con hormigón contaminado con sal, y se ha determinado la velocidad de corrosión y la resistencia a la formación de picaduras de diferentes calidades de aceros inoxidables (austeníticos y dúplex, tanto conformadas en caliente como en frío.

Lake on life support: Evaluating urban lake management measures by using a coupled 1D-modelling approach

Science.gov (United States)

Ladwig, Robert; Kirillin, Georgiy; Hinkelmann, Reinhard; Hupfer, Michael

2017-04-01

Urban surface water systems and especially lakes are heavily stressed and modified systems to comply with water management goals and expectations. In this study we focus on Lake Tegel in Berlin, Germany, as a representative of heavily modified urban lakes. In the 20th century, Lake Tegel received increased loadings of nutrients and leached heavy metals from an upstream sewage farm resulting in severe eutrophication problems. The construction of two upstream treatment plants caused a lowering of nutrient concentrations and a re-oligotrophication of the lake. Additionally, artificial aerators, to keep the hypolimnion oxic, and a lake pipeline, to bypass water for maintaining a minimum discharge, went into operation. Lake Tegel is still heavily used for drinking water extraction by bank filtration. These interacting management measures make the system vulnerable to changing climate conditions and pollutant loads. Past modelling studies have shown the complex hydrodynamics of the lake. Here, we are following a simplified approach by using a less computational time consuming vertical 1D-model to simulate the hydrodynamics and the ecological interactions of the system by coupling the General Lake Model to the Aquatic Ecodynamics Model Library 2. For calibration of the multidimensional parameter space we applied the Covariance Matrix Adaption-Evolution Strategy algorithm. The model is able to sufficiently replicate the vertical field temperature profiles of Lake Tegel as well as to simulate similar concentration ranges of phosphate, dissolved oxygen and nitrate. The calibrated model is used to run an uncertainty analysis by sampling the simulated data within the meaning of the Metropolis-Hastings algorithm. Finally, we are evaluating different scenarios: (1) changing air temperatures, precipitation and wind speed due to effects of climate change, (2) decreased discharges into the lake due to bypassing treated effluents into a near stream instead of Lake Tegel, and (3

Forest blowdown and lake acidification

International Nuclear Information System (INIS)

Dobson, J.E.; Rush, R.M.; Peplies, R.W.

1990-01-01

The authors examine the role of forest blowdown in lake acidification. The approach combines geographic information systems (GIS) and digital remote sensing with traditional field methods. The methods of analysis consist of direct observation, interpretation of satellite imagery and aerial photographs, and statistical comparison of two geographical distributions-one representing forest blow-down and another representing lake chemistry. Spatial and temporal associations between surface water pH and landscape disturbance are strong and consistent in the Adirondack Mountains of New York. In 43 Adirondack Mountain watersheds, lake pH is associated with the percentage of the watershed area blown down and with hydrogen ion deposition (Spearman rank correlation coefficients of -0.67 and -0.73, respectively). Evidence of a temporal association is found at Big Moose Lake and Jerseyfield Lake in New York and the Lygners Vider Plateau of Sweden. They conclude that forest blowdown facilities the acidification of some lakes by altering hydrologic pathways so that waters (previously acidified by acid deposition and/or other sources) do not experience the neutralization normally available through contact with subsurface soils and bedrock. Increased pipeflow is suggested as a mechanism that may link the biogeochemical impacts of forest blowdown to lake chemistry

Thermal Regime of A Deep Temperate Lake and Its Response to Climate Change: Lake Kuttara, Japan

Directory of Open Access Journals (Sweden)

Kazuhisa A. Chikita

2018-02-01

Full Text Available A deep temperate lake, Lake Kuttara, Hokkaido, Japan (148 m deep at maximum was completely ice-covered every winter in the 20th century. However, ice-free conditions of the lake over winter occurred three times in the 21st century, which is probably due to global warming. In order to understand how thermal regime of the lake responds to climate change, a change in lake mean water temperature from the heat storage change was calculated by integrating observed water temperature over water depths and by numerical calculation of heat budget components based on hydrometeorological data. As a result, a temporal variation of lake mean water temperature from the heat budget calculation was very reasonable to that from the observed water temperature (determination coefficient R2 = 0.969. The lowest lake mean temperature for non-freeze was then evaluated at −1.87 °C, referring to the zero level at 6.80 °C. The 1978–2017 data at a meteorological station near Kuttara indicated that there are significant (less than 5% level long-term trends for air temperature (+0.024 °C/year and wind speed (−0.010 m/s/year. In order to evaluate the effects of climate change on freeze-up patterns, a sensitivity analysis was carried out for the calculated lake mean water temperature. It is noted that, after two decades, the lake could be ice-free once per every two years.

Trophic diversity of Poznań Lakeland lakes

Directory of Open Access Journals (Sweden)

Dzieszko Piotr

2015-06-01

Full Text Available The main goal of the presented work is to determine the current trophic state of 31 lakes located in Poznań Lakeland. These lakes are included in the lake monitoring programme executed by the Voivodship Environmental Protection Inspectorate in Poznań. The place in the trophic classification for investigated lakes was determined as well as the relationships between their trophic state indices. The trophic state of investigated lakes in the research area is poor. More than a half of the investigated lakes are eutrophic. Depending on the factor that is taken into account the trophic state of investigated lakes differs radically.

Para una crítica de investigaciones académicas y periodísticas sobre la violencia en el fútbol, a partir de La doce, la verdadera historia de la barra brava de Boca : Grabia, Gustavo. Sudamericana, Buenos Aires, 2009

OpenAIRE

Sodo, Juan Manuel

2010-01-01

Prosa atrapante, reconstrucción de datos seria y rigurosidad informativa mediante, este sesudo trabajo de Grabia, a lo largo de cinco minuciosos capítulos y casi 250 páginas, nos ofrece una exhaustiva cartografía de la red de relaciones que La 12 ha ido tejiendo con dirigentes, punteros políticos, policía, jueces, futbolistas, empresarios, candidatos a elecciones, directores técnicos, hinchas famosos, otras barras... a lo largo de su convulsionada historia, desde que esta hinchada aparece y e...

National Lakes Assessment Data

Data.gov (United States)

U.S. Environmental Protection Agency — The National Lakes Assessment (NLA) is a first-ever statistically-valid survey of the biological condition of lakes and reservoirs throughout the U.S. The U.S....

Water pollution control technology and strategy for river-lake systems: a case study in Gehu Lake and Taige Canal.

Science.gov (United States)

Zhang, Yimin; Zhang, Yongchun; Gao, Yuexiang; Zhang, Houhu; Cao, Jianying; Cai, Jinbang; Kong, Xiangji

2011-07-01

The Taoge water system is located in the upstream of Taihu Lake basin and is characterized by its multi-connected rivers and lakes. In this paper, current analyses of hydrology, hydrodynamics and water pollution of Gehu Lake and Taige Canal are presented. Several technologies are proposed for pollution prevention and control, and water environmental protection in the Taihu Lake basin. These included water pollution control integration technology for the water systems of Gehu Lake, Taige Canal and Caoqiao River. Additionally, river-lake water quality and quantity regulation technology, ecological restoration technology for polluted and degraded water bodies, and water environmental integration management and optimization strategies were also examined. The main objectives of these strategies are to: (a) improve environmental quality of relative water bodies, prevent pollutants from entering Gehu Lake and Taige Canal, and ensure that the clean water after the pre-treatment through Gehu Lake is not polluted before entering the Taihu Lake through Taige Canal; (b) stably and efficiently intercept and decrease the pollution load entering the lake through enhancing the river outlet ecological system structure function and water self-purifying capacity, and (c) designate Gehu Lake as a regulation system for water quality and water quantity in the Taoge water system and thus guarantee the improvement of the water quality of the inflow into Taihu Lake.

Ecological regime shifts and changes of lake ecosystem service in a shallow Yangtze lake (Taibai Lake, China) over the past 150 years

Science.gov (United States)

Dong, X.; Xu, M.; Yang, X.

2017-12-01

Shallow lakes provide a range of ecosystem services such as water supply, biodiversity, aquaculture, tourism, shipping and flood regulation. Over recent decades, many lakes have become severely deteriorated due to a coupled natural and human disturbance. Given the limited monitoring records, however, we still have little knowledge on how, when and why those lake experienced ecological status shifts, and how the lake ecosystem service changed. Paleolimnological techniques were widely used in understanding the historical environmental and ecological changes. Here, we chose a typical eutrophic shallow lake, Taibai Lake, and acquired geochemistry proxies, grain size, diatom, cladocera and chironomid from a 210Pb and 137Cs dated sediment core. Document records and monitoring data are also included as important marks of social and environmental change. A T-test based algorithm of STARS reveal at least two ecological shifts, respectively in the 1960s and the 1990s. The sudden shift in the 1960s is supposed to be influenced by a dam and sluice construction in the 1950s and another shift in the 1990s should be a critical transition due to the alternation of ecosystem structure for higher fishery production. Correspondingly, lake ecosystem service (LES) also experienced significant changes. Prior to 1930s, different types of LES kept relatively stable with low values. With the dam construction in the 1960s, the changed hydrological condition led to gradual increases in both regulation and provision service. However, with much effort on fishery and reclamation, the regulation service of the lake decreased, exhibiting a tradeoff among LES. After 1990s, with intense aquaculture, most types of LSE suffered a further decrease. The long-term records exhibited that ecosystem services in primary productivity and biodiversity maintenance increased (synergies) whereas services in water-purification and climate regulating decreased significantly (tradeoffs) since 1950s, when local

Mid Holocene lake level and shoreline behavior during the Nipissing phase of the upper Great Lakes at Alpena, Michigan, USA

Science.gov (United States)

Thompson, T.A.; Lepper, K.; Endres, A.L.; Johnston, J.W.; Baedke, S.J.; Argyilan, E.P.; Booth, R.K.; Wilcox, D.A.

2011-01-01

The Nipissing phase was the last pre-modern high-water stage of the upper Great Lakes. Represented as either a one- or two-peak highstand, the Nipissing occurred following a long-term lake-level rise. This transgression was primarily an erosional event with only the final stage of the transgression preserved as barriers, spits, and strandplains of beach ridges. South of Alpena, Michigan, mid to late Holocene coastal deposits occur as a strandplain between Devils Lake and Lake Huron. The landward part of this strandplain is a higher elevation platform that formed during the final stage of lake-level rise to the Nipissing peak. The pre-Nipissing shoreline transgressed over Devils Lake lagoonal deposits from 6.4 to 6.1. ka. The first beach ridge formed ~ 6. ka, and then the shoreline advanced toward Lake Huron, producing beach ridges about every 70. years. This depositional regression produced a slightly thickening wedge of sediment during a lake-level rise that formed 20 beach ridges. The rise ended at 4.5. ka at the Nipissing peak. This peak was short-lived, as lake level fell > 4. m during the following 500. years. During this lake-level rise and subsequent fall, the shoreline underwent several forms of shoreline behavior, including erosional transgression, aggradation, depositional transgression, depositional regression, and forced regression. Other upper Great Lakes Nipissing platforms indicate that the lake-level change observed at Alpena of a rapid pre-Nipissing lake-level rise followed by a slower rise to the Nipissing peak, and a post-Nipissing rapid lake-level fall is representative of mid Holocene lake level in the upper Great Lakes. ?? 2011 Elsevier B.V.

Late Pleistocene to Holocene lake levels of Lake Warner, Oregon (USA) and their effect on archaeological site distribution patterns

Science.gov (United States)

Wriston, T.; Smith, G. M.

2017-12-01

Few chronological controls are available for the rise and fall of small pluvial lake systems in the Northwestern Great Basin. Within Warner Basin this control was necessary for interpretation of known archaeological sites and for predicting where evidence of its earliest inhabitants might be expected. We trenched along relic beach ridges of Lake Warner, surveyed a stratified sample of the area for archaeological sites, and excavated some sites and a nearby rockshelter. These efforts produced new ages that we used to construct a lake level curve for Lake Warner. We found that the lake filled the valley floor between ca. 30,000 cal yr BP and ca. 10,300 cal yr BP. In nearby basins, several oscillations are evident before ca. 21,100 cal yr BP, but a steep rise to the LGM maximum occurred between 21,000 and 20,000 cal yr BP. Lake Warner likely mirrored these changes, dropped to the valley floor ca. 18,340 cal yr BP, and then rose to its maximum highstand when its waters briefly reached 1454 m asl. After this highstand the lake receded to moderately high levels. Following ca. 14,385 cal yr BP, the lake oscillated between moderate to moderately-high levels through the Bolling-Allerod interstadials and into the Younger Dryas stadial. The basin's first occupants arrived along its shore around this time, while the lake still filled the valley floor. These earliest people carried either Western Stemmed or Clovis projectile points, both of which are found along the lake margin. The lake receded into the valley floor ca. 10,300 cal yr BP and dune development began, ringing wetlands and small lakes that persisted in the footprint of the once large lake. By the time Mazama tephra fell 7,600 cal yr BP it blanketed pre-existing dunes and marsh peats. Our Lake Warner lake level curve facilitates interdisciplinary testing and refinement of it and similar curves throughout the region while helping us understand the history of lake and the people who lived along its shores.

Development of a zoning-based environmental-ecological-coupled model for lakes to assess lake restoration effect

Science.gov (United States)

Xu, Mengjia; Zou, Changxin; Zhao, Yanwei

2017-04-01

Environmental/ecological models are widely used for lake management as they provide a means to understand physical, chemical and biological processes in highly complex ecosystems. Most research focused on the development of environmental (water quality) and ecological models, separately. Limited studies were developed to couple the two models, and in these limited coupled models, a lake was regarded as a whole for analysis (i.e., considering the lake to be one well-mixed box), which was appropriate for small-scale lakes and was not sufficient to capture spatial variations within middle-scale or large-scale lakes. This paper seeks to establish a zoning-based environmental-ecological-coupled model for a lake. The Baiyangdian Lake, the largest freshwater lake in Northern China, was adopted as the study case. The coupled lake models including a hydrodynamics and water quality model established by MIKE21 and a compartmental ecological model used STELLA software have been established for middle-sized Baiyangdian Lake to realize the simulation of spatial variations of ecological conditions. On the basis of the flow field distribution results generated by MIKE21 hydrodynamics model, four water area zones were used as an example for compartmental ecological model calibration and validation. The results revealed that the developed coupled lake models can reasonably reflected the changes of the key state variables although there remain some state variables that are not well represented by the model due to the low quality of field monitoring data. Monitoring sites in a compartment may not be representative of the water quality and ecological conditions in the entire compartment even though that is the intention of compartment-based model design. There was only one ecological observation from a single monitoring site for some periods. This single-measurement issue may cause large discrepancies particularly when sampled site is not representative of the whole compartment. The

lakemorpho: Calculating lake morphometry metrics in R.

Science.gov (United States)

Hollister, Jeffrey; Stachelek, Joseph

2017-01-01

Metrics describing the shape and size of lakes, known as lake morphometry metrics, are important for any limnological study. In cases where a lake has long been the subject of study these data are often already collected and are openly available. Many other lakes have these data collected, but access is challenging as it is often stored on individual computers (or worse, in filing cabinets) and is available only to the primary investigators. The vast majority of lakes fall into a third category in which the data are not available. This makes broad scale modelling of lake ecology a challenge as some of the key information about in-lake processes are unavailable. While this valuable in situ information may be difficult to obtain, several national datasets exist that may be used to model and estimate lake morphometry. In particular, digital elevation models and hydrography have been shown to be predictive of several lake morphometry metrics. The R package lakemorpho has been developed to utilize these data and estimate the following morphometry metrics: surface area, shoreline length, major axis length, minor axis length, major and minor axis length ratio, shoreline development, maximum depth, mean depth, volume, maximum lake length, mean lake width, maximum lake width, and fetch. In this software tool article we describe the motivation behind developing lakemorpho , discuss the implementation in R, and describe the use of lakemorpho with an example of a typical use case.

Comparison of the hydrogeology and water quality of a ground-water augmented lake with two non-augmented lakes in northwest Hillsborough County, Florida

Science.gov (United States)

Metz, Patricia A.; Sacks, Laura A.

2002-01-01

The hydrologic effects associated with augmenting a lake with ground water from the Upper Floridan aquifer were examined in northwest Hillsborough County, Florida, from June 1996 through May 1999. The hydrogeology, ground-water flow patterns, water budgets, and water-quality characteristics were compared between a lake that has been augmented for more than 30 years (Round Lake) and two nearby nonaugmented lakes (Dosson Lake and Halfmoon Lake). Compared to the other study lakes, Round Lake is in a more leakage-dominated hydrogeologic setting. The intermediate confining unit is thin or highly breached, which increases the potential for vertical ground-water flow. Round Lake has the least amount of soft, organic lake-bottom sediments and the lake bottom has been dredged deeper and more extensively than the other study lakes, which could allow more leakage from the lake bottom. The area around Round Lake has experienced more sinkhole activity than the other study lakes. During this study, three sinkholes developed around the perimeter of the lake, which may have further disrupted the intermediate confining unit.Ground-water flow patterns around Round Lake were considerably different than the nonaugmented lakes. For most of the study, groundwater augmentation artificially raised the level of Round Lake to about 2 to 3 feet higher than the adjacent water table. As a result, lake water recharged the surficial aquifer around the entire lake perimeter, except during very wet periods when ground-water inflow occurred around part of the lake perimeter. The non-augmented lakes typically had areas of ground-water inflow and areas of lake leakage around their perimeter, and during wet periods, ground-water inflow occurred around the entire lake perimeter. Therefore, the area potentially contributing ground water to the non-augmented lakes is much larger than for augmented Round Lake. Vertical head loss within the surficial aquifer was greater at Round Lake than the other study

[Species and size composition of fishes in Barra de Navidad lagoon, Mexican central Pacific].

Science.gov (United States)

González-Sansón, Gaspar; Aguilar-Betancourt, Consuelo; Kosonoy-Aceves, Daniel; Lucano-Ramírez, Gabriela; Ruiz-Ramírez, Salvador; Flores-Ortega, Juan Ramón; Hinojosa-Larios, Angel; de Asís Silva-Bátiz, Francisco

2014-03-01

Coastal lagoons are considered important nursery areas for many coastal fishes. Barra de Navidad coastal lagoon (3.76km2) is important for local economy as it supports tourism development and artisanal fisheries. However, the role of this lagoon in the dynamics of coastal fish populations is scarcely known. Thus, the objectives of this research were: to characterize the water of the lagoon and related weather conditions, to develop a systematic list of the ichthyofauna, and to estimate the proportion of juveniles in the total number of individuals captured of most abundant species. Water and fish samples were collected between March 2011 and February 2012. Physical and chemical variables were measured in rainy and dry seasons. Several fishing gears were used including a cast net, beach purse seine and gillnets of four different mesh sizes. Our results showed that the lagoon is most of the time euhaline (salinity 30-40ups), although it can be mixopolyhaline (salinity 18-30ups) during short periods. Chlorophyll and nutrients concentrations suggested eutrophication in the lagoon. Mean water temperature changed seasonally from 24.9 degrees C (April, high tide) to 31.4 degrees C (October, low tide). Considering ichthyofauna species, a total of 36 448 individuals of 92 species were collected, 31 of them adding up to 95% of the total of individuals caught. Dominant species were Anchoa spp. (44.6%), Diapterus peruvianus (10.5%), Eucinostomus currani (8.1%), Cetengraulis mysticetus (7.8%), Mugil curema (5.2%) and Opisthonema libertate (4.5%). The lagoon is an important juvenile habitat for 22 of the 31 most abundant species. These included several species of commercial importance such as snappers (Lutjanus argentiventris, L. colorado and L. novemfasciatus), snook (Centropomus nigrescens) and white mullet (Mugil curema). Other four species seem to use the lagoon mainly as adults. This paper is the first contribution on the composition of estuarine ichthyofauna in Jalisco

Hydro biological investigations of lake Drukshiai

International Nuclear Information System (INIS)

Mazheikaite, S.; Sinkevichiene, Z.; Marchiulioniene, D.; Astrauskas, A.; Barshiene, J.

1998-01-01

Purposes of this research were to investigate changes in the physical, chemical and tropic conditions of Lake Drukshiai caused by the combined effect of Ignalina NPP and how it effects on structures and function of biocenoses; to estimate the influence of phytocenoses, zoocenoses and bacteriocenoses on the quality of water in Lake Drukshiai; to estimate the eco toxicological state of Lake Drukshiai. According to the complex hydro biological investigations on Lake Drukshiai - Ignalina NPP cooler great changes in planktonic organism community, tendencies of those changes in different ecological zones were evaluated in 1993 - 1997. The amount of species of most dominant planktonic organisms in 1993 - 1997 decreased 2-3 times in comparison with that before Ignalina NPP operation: phytoplankton from 116 to 40 - 50, zooplankton - from 233 to 139. The organic matter increasing tendency was determined in bottom sediments of the lake. The highest amount of it was evaluated in the south - eastern part of the lake. 69 water macrophyte species were found in bottom sediments during the investigation period. 16 species were not found in this lake earlier. Abundance of filamentous green algae was registered.The rates of fish communities successional transformation were ten times in excess of those of the given processes in natural lakes. Moreover the comparison of results on Lake Drukshiai bioindication analysis with changes of comparable bio markers which were obtained from other water systems of Lithuania, Switzerland, Sweden and Poland, including those with active nuclear power plants in their environment was carried out. It was determined that the functional and structural changes in Lake Drukshiai biota are mostly caused by chemical pollution. It was found out that the frequency of cytogenetic damage emerged as a specific radionuclide - caused effect in aquatic organisms inhabiting Lake Drukshiai, is slightly above the background level and is 5 times lower than the same

Anaerobic Oxidation of Methane in a French meromictic lake (Lake Pavin): Who is responsible?

Science.gov (United States)

Grossi, V.; Attard, E.; Birgel, D.; Schaeffer, P.; Jézéquel, D.; Lehours, A.

2012-12-01

Methane is an important greenhouse gas and its biogeochemical cycle is of primary significance to the global carbon cycle. The Anaerobic Oxidation of Methane (AOM) has been estimated to be responsible for >90% of methane consumption. This biogeochemical process has been increasingly documented during the last two decades but the underlying microbial processes and their key agents remain incompletely understood. Freshwater lakes account for 2-10% of the total emissions of methane and are therefore an important part of the global methane cycle. Lake Pavin is a French meromictic crater lake with unusual hydrological characteristics: its morphology (depth >92m, mean diameter 750m) induce that waters below 60m are never mixed with overlying waters and remain permanently anoxic. The deep anoxic waters of Lake Pavin contain high concentrations (i.e. 4 mM) of methane but, contrary to other aquatic systems, almost no methane escapes from the lake. Previous biogeochemical and modeling studies suggest that methane is preferentially consumed within the oxic-anoxic transition zone (ca. 55-60 m depth) but that ca. 30% of methane oxidation occurs in the anoxic part of the lake. Phylogenetic (16S rRNA) analyses showed that ANME generally involved in AOM (ANME-1, -2 and -3) are not present in Lake Pavin. Other archaeal groups that do not have any cultured representatives so far appear well represented in the anoxic parts of the lake but their implication in AOM is not demonstrated. The analysis of lipid biomarkers using GC-MS and LC-MS revealed the presence of a low diversity of archaeal-specific biomarkers in the superficial sediments and in the anoxic waters of the lake. Archaeol and caldarcheaol (GDGT-0) are the two main archaeal core lipids detected; other biomarkers generally present in ANME such as pentamethylicosane or hydroxyarchaeol are not present. However, the stable carbon isotopic composition of archaeol (δ13C = -18‰) and of the biphytane chain of GDGT-0 (δ13C

[Similarities and differences in absorption characteristics and composition of CDOM between Taihu Lake and Chaohu Lake].

Science.gov (United States)

Shi, Kun; Li, Yun-mei; Wang, Qiao; Yang, Yu; Jin, Xin; Wang, Yan-fei; Zhang, Hong; Yin, Bin

2010-05-01

Field experiments are conducted separately in Taihu Lake and Chaohu Lake on Apr. and Jun. 2009. The changes in absorption spectra of chromophoric dissolved organic matter (CDOM) characteristics are analyzed using spectral differential analysis technology. According the spectral differential characteristic of absorption coefficient; absorption coefficient from 240 to 450 nm is divided into different stages, and the value of spectral slope S is calculated in each stage. In Stage A, S value of CDOM in Taihu Lake and Chaohu Lake are 0.0166-0.0102 nm(-1) [average (0.0132 +/- 0.0017) nm(-1)], 0.029-0.017 nm(-1) [average (0.0214 +/- 0.0024) nm(-1)]. In Stage B, S values are 0.0187-0.0148 nm(-1) [average (0.0169 +/- 0.001) nm(-1)], 0.0179-0.0055 nm(-1) [average (0.0148 +/- 0.002) nm(-1)]. In Stage C, S values are 0.0208-0.0164 nm(-1) [average (0.0186 +/- 0.0009) nm(-1)], 0.0253-0.0161 nm(-1) [average (0.0197 +/- 0.002) nm(-1)]. The results can be concluded as: (1) Absorption coefficient of water in Taihu Lake, and its contribution to absorption of each component is less than that of water in Chaohu Lake, however the standardized absorption coefficient is larger than that in Chaohu Lake. (2) Both in Taihu Lake and Chaohu Lake, derivative spectra of CDOM absorption coefficient reached valley at 260nm, then rise to top at 290 nm, CDOM absorption coefficient can be delivered into three stages. (3) Generally speaking, content of CDOM in Taihu Lake is less than in Chaohu Lake. (4) pectrum slope (S value) of CDOM is related to composition of CDOM, when content of humic acid in CDOM gets higher, S value of Stage B is the most sensitive value, then is the S value of Stage C. Oppositely, S value of Stage B gets the most sensitive value, then is the S value of Stage A; the least sensitive value is in Stage B.

[Analysis of tartrazine aluminum lake and sunset yellow aluminum lake in foods by capillary zone electrophoresis].

Science.gov (United States)

Zhang, Yiding; Chang, Cuilan; Guo, Qilei; Cao, Hong; Bai, Yu; Liu, Huwei

2014-04-01

A novel analytical method for tartrazine aluminum lake and sunset yellow aluminum lake using capillary zone electrophoresis (CZE) was studied. The pigments contained in the color lakes were successfully separated from the aluminum matrix in the pre-treatment process, which included the following steps: dissolve the color lakes in 0.1 mol/L H2SO4, adjust the pH of the solution to 5.0, then mix it with the solution of EDTA x 2Na and heat it in a water bath, then use polyamide powder as the stationary phase of solid phase extraction to separate the pigments from the solution, and finally elute the pigments with 0.1 mol/L NaOH. The CZE conditions systematically optimized for tartrazine aluminum lake were: 48.50 cm of a fused silica capillary with 40.00 cm effective length and 50 microm i. d., the temperature controlled at 20.0 degrees C, 29.0 kV applied, HPO4(2-)-PO4(3-) (0.015 mol/L, pH 11.45) solution as running buffer, detection at 263 nm. The conditions for sunset yellow aluminum lake were: the same capillary and temperature, 25.0 kV applied, HPO4(2-)-PO4(3-) (0.025 mol/L, pH 11.45) solution as running buffer, detection at 240 nm. The limits of detection were 0.26 mg/L and 0.27 mg/L, and the linear ranges were 0.53-1.3 x 10(2) mg/L and 0.54-1.4 x 10(2) mg/L for tartrazine aluminum lake and sunset yellow aluminum lake, respectively. The RSDs were 4.3% and 5.7% (run to run, n = 6), 5.6% and 6.0% (day to day, n = 6) for tartrazine aluminum lake and sunset yellow aluminum lake, respectively. Further developments for this method could make it a routinely used method analyzing color lakes in foods.

Trophic development in a volcanic lake with closed hydric balance. Lake Martignano

International Nuclear Information System (INIS)

Falleni, F.; Bruno, M.; Marchiori, E.; Congestri, R.; Gasperi, E.; Brambullo, M.; Amadeio, R.

2000-01-01

Martignano lake is a particular charming volcanic lake in the countryside of Rome. Recently it was included in a project of Regional Wildlife Park. The lack of immissaries and emissaries, the quite long renewal time and the very short homeothermic period of two-months in a year, make the lake susceptible of trophic evolution. The comparison between the present data and those from previous studies seems to confirm such a slow development towards this way, with a nutrient level (nitrate 0.97 mg/L; total phosphorus 11.14 μg/L) and chlorophyll a concentrations (10.68 μg/L), typical of mesotrophic waters. The analysis of nutrient data expressed as annual mean value in percentage from the coastal stations, suggests an under lied farming influence, and points out the need to adopt fast reduction measures, to lower the phosphorus load in acceptable levels for the lake ecosystem [it

Contaminant Monitoring Strategy for Henrys Lake, Idaho

Energy Technology Data Exchange (ETDEWEB)

John S. Irving; R. P. Breckenridge

1992-12-01

Henrys Lake, located in southeastern Idaho, is a large, shallow lake (6,600 acres, {approx} 17.1 feet maximum depth) located at 6,472 feet elevation in Fremont Co., Idaho at the headwaters of the Henrys Fork of the Snake River. The upper watershed is comprised of high mountains of the Targhee National Forest and the lakeshore is surrounded by extensive flats and wetlands, which are mostly privately owned. The lake has been dammed since 1922, and the upper 12 feet of the lake waters are allocated for downriver use. Henrys Lake is a naturally productive lake supporting a nationally recognized ''Blue Ribbon'' trout fishery. There is concern that increasing housing development and cattle grazing may accelerate eutrophication and result in winter and early spring fish kills. There has not been a recent thorough assessment of lake water quality. However, the Department of Environmental Quality (DEQ) is currently conducting a study of water quality on Henrys Lake and tributary streams. Septic systems and lawn runoff from housing developments on the north, west, and southwest shores could potentially contribute to the nutrient enrichment of the lake. Many houses are on steep hillsides where runoff from lawns, driveways, etc. drain into wetland flats along the lake or directly into the lake. In addition, seepage from septic systems (drainfields) drain directly into the wetlands enter groundwater areas that seep into the lake. Cattle grazing along the lake margin, riparian areas, and uplands is likely accelerating erosion and nutrient enrichment. Also, cattle grazing along riparian areas likely adds to nutrient enrichment of the lake through subsurface flow and direct runoff. Stream bank and lakeshore erosion may also accelerate eutrophication by increasing the sedimentation of the lake. Approximately nine streams feed the lake (see map), but flows are often severely reduced or completely eliminated due to irrigation diversion. In addition, subsurface

Eruptive behavior of the Marum/Mbwelesu lava lake, Vanuatu and comparisons with lava lakes on Earth and Io

Science.gov (United States)

Radebaugh, Jani; Lopes, Rosaly M.; Howell, Robert R.; Lorenz, Ralph D.; Turtle, Elizabeth P.

2016-08-01

Observations from field remote sensing of the morphology, kinematics and temperature of the Marum/Mbwelesu lava lake in the Vanuatu archipelago in 2014 reveal a highly active, vigorously erupting lava lake. Active degassing and fountaining observed at the 50 m lava lake led to large areas of fully exposed lavas and rapid ( 5 m/s) movement of lava from the centers of upwelling outwards to the lake margins. These rapid lava speeds precluded the formation of thick crust; there was never more than 30% non-translucent crust. The lava lake was observed with several portable, handheld, low-cost, near-infrared imagers, all of which measured temperatures near 1000 °C and one as high as 1022 °C, consistent with basaltic temperatures. Fine-scale structure in the lava fountains and cooled crust was visible in the near infrared at 5 cm/pixel from 300 m above the lake surface. The temperature distribution across the lake surface is much broader than at more quiescent lava lakes, peaking 850 °C, and is attributed to the highly exposed nature of the rapidly circulating lake. This lava lake has many characteristics in common with other active lava lakes, such as Erta Ale in Ethiopia, being confined, persistent and high-temperature; however it was much more active than is typical for Erta Ale, which often has > 90% crust. Furthermore, it is a good analogue for the persistent, high-temperature lava lakes contained within volcanic depressions on Jupiter's moon Io, such as Pele, also believed from spacecraft and ground-based observations to exhibit similar behavior of gas emission, rapid overturn and fountaining.

Polycyclic aromatic hydrocarbons (PAHs) in surface sediments of two lakes of the Dongting Lake district in Hunan, China

Science.gov (United States)

He, Jiang; Yang, Yajing; Zhang, Lugang; Luo, Yushuang; Liu, Fei; Yang, Pinhong

2018-04-01

In this paper, 18 and 12 surface sediment samples were collected from Datong Lake and Shanpo Lake, respectively, and the 16 USEPA priority Polycyclic aromatic hydrocarbons (PAHs) in these samples were detected. The result indicated that the Σ16PAHs ranged from 206.56 to 1058.98 ng.g-1 with an average concentration of 667.22 ng.g-1 in sediments from Datong Lake, whereas it ranged from 90.62 to 900.70 ng.g-1 with an average concentration of 364.97 ng.g-1 in sediments from Shanpo Lake. The concentrations of individual PAHs in sediments ranged from 5.50 to 85.23 and from 4.39 to 52.74 ng.g-1 in Datong Lake and Shanpo Lake, respectively. According to the indexes such as HMW/LMW, Ant/(Ant+Phe), Flua/(Flua+Pyr), IcdP/(IcdP+BghiP), and BaA/(BaA+Chr), the PAHs in sediments from both lakes are mainly of pyrogenic origin. The total BaP equivalent in the surface sediment samples from Datong Lake and Shanpo Lake is 42.77 and 33.35 ng.g-1, respectively.

Effectiveness of a refuge for Lake Trout in Western Lake Superior II: Simulation of future performance

Science.gov (United States)

Akins, Andrea L; Hansen, Michael J.; Seider, Michael J.

2015-01-01

Historically, Lake Superior supported one of the largest and most diverse Lake Trout Salvelinus namaycush fisheries in the Laurentian Great Lakes, but Lake Trout stocks collapsed due to excessive fishery exploitation and predation by Sea Lampreys Petromyzon marinus. Lake Trout stocking, Sea Lamprey control, and fishery regulations, including a refuge encompassing Gull Island Shoal (Apostle Islands region), were used to enable recovery of Lake Trout stocks that used this historically important spawning shoal. Our objective was to determine whether future sustainability of Lake Trout stocks will depend on the presence of the Gull Island Shoal Refuge. We constructed a stochastic age-structured simulation model to assess the effect of maintaining the refuge as a harvest management tool versus removing the refuge. In general, median abundances of age-4, age-4 and older (age-4+), and age-8+ fish collapsed at lower instantaneous fishing mortality rates (F) when the refuge was removed than when the refuge was maintained. With the refuge in place, the F that resulted in collapse depended on the rate of movement into and out of the refuge. Too many fish stayed in the refuge when movement was low (0–2%), and too many fish became vulnerable to fishing when movement was high (≥22%); thus, the refuge was more effective at intermediate rates of movement (10–11%). With the refuge in place, extinction did not occur at any simulated level of F, whereas refuge removal led to extinction at all combinations of commercial F and recreational F. Our results indicate that the Lake Trout population would be sustained by the refuge at all simulated F-values, whereas removal of the refuge would risk population collapse at much lower F (0.700–0.744). Therefore, the Gull Island Shoal Refuge is needed to sustain the Lake Trout population in eastern Wisconsin waters of Lake Superior.

Algae Bloom in a Lake

Directory of Open Access Journals (Sweden)

David Sanabria

2008-01-01

Full Text Available The objective of this paper is to determine the likelihood of an algae bloom in a particular lake located in upstate New York. The growth of algae in this lake is caused by a high concentration of phosphorous that diffuses to the surface of the lake. Our calculations, based on Fick's Law, are used to create a mathematical model of the driving force of diffusion for phosphorous. Empirical observations are also used to predict whether the concentration of phosphorous will diffuse to the surface of this lake within a specified time and under specified conditions.

Sediment deposition and sources into a Mississippi River floodplain lake; Catahoula Lake, Louisiana

Science.gov (United States)

Latuso, Karen D.; Keim, Richard F.; King, Sammy L.; Weindorf, David C.; DeLaune, Ronald D.

2017-01-01

Floodplain lakes are important wetlands on many lowland floodplains of the world but depressional floodplain lakes are rare in the Mississippi River Alluvial Valley. One of the largest is Catahoula Lake, which has existed with seasonally fluctuating water levels for several thousand years but is now in an increasingly hydrologically altered floodplain. Woody vegetation has been encroaching into the lake bed and the rate of this expansion has increased since major human hydrologic modifications, such as channelization, levee construction, and dredging for improvement of navigation, but it remains unknown what role those modifications may have played in altering lake sedimentation processes. Profiles of thirteen 137Cs sediment cores indicate sedimentation has been about 0.26 cm y− 1 over the past 60 years and has been near this rate since land use changes began about 200 years ago (210Pb, and 14C in Tedford, 2009). Carbon sequestration was low (10.4 g m− 2 y− 1), likely because annual drying promotes mineralization and export. Elemental composition (high Zr and Ti and low Ca and K) and low pH of recent (sediments suggest Gulf Coastal Plain origin, but below the recent sediment deposits, 51% of sediment profiles showed influence of Mississippi River alluvium, rich in base cations such as K+, Ca2 +, and Mg2 +. The recent shift to dominance of Coastal Plain sediments on the lake-bed surface suggests hydrologic modification has disconnected the lake from sediment-bearing flows from the Mississippi River. Compared to its condition prior to hydrologic alterations that intensified in the 1930s, Catahoula Lake is about 15 cm shallower and surficial sediments are more acidic. Although these results are not sufficient to attribute ecological changes directly to sedimentological changes, it is likely the altered sedimentary and hydrologic environment is contributing to the increased dominance of woody vegetation.

BATHYMETRIC STUDY OF WADI EL-RAYAN LAKES, EGYPT

Directory of Open Access Journals (Sweden)

Radwan Gad Elrab ABD ELLAH

2016-12-01

Full Text Available Bathymetry is a technique of measuring depths to determine the morphometry of water bodies. The derivation of bathymetry from the surveys is one of the basic researches of the aquatic environment, which has several practical implications to on the lake environment and it's monitoring. Wadi El-Rayan, as Ramsar site, is a very important wetland, in Egypt, as a reservoir for agricultural drainage water, fisheries and tourism. The Lakes are man-made basins in the Fayoum depression. Wadi El-Rayan Lakes are two reservoirs (upper Lake and Lower Lake, at different elevations. The Upper Lake is classified as open basin, while the Lower Lake is a closed basin, with no significant obvious water outflow. During recent decades, human impact on Wadi El-Rayan Lakes has increased due to intensification of agriculture and fish farming. Analyses of bathyemtric plans from 1996, 2010 and 2016 showed, the differences between morphometric parameters of the Upper Lake were generally small, while the Lower Lake changes are obvious at the three periods. The small fluctuate, in the features of Upper Lake is due to the water balance between the water inflow and water. The Lower Lake has faced extreme water loss through last twenty years is due to the agricultural lands and fish farms extended in the depression. The Upper Lake is rich in Lakeshores macrophyets, while decline the water plants in the Lower Lake. With low water levels, in the Lower Lake, the future continuity of the Lake system is in jeopardy

Análise da taxa de impermeabilização e tempo de concentração nas sub-bacias da área urbana de Barra do Garças – MT, Pontal do Araguaia – MT e Aragarças – GO

Directory of Open Access Journals (Sweden)

G. B. M. Rezende

2015-12-01

Full Text Available A presente pesquisa objetivou verificar as taxas de impermeabilização e tempo de concentração das sub-bacias presentes na área urbana de Barra do Garças – MT, Pontal do Araguaia – MT e Aragarças – GO. Tais variáveis podem auxiliar no ordenamento territorial da expansão urbana, bem como no planejamento urbano dessas cidades. Os resultados demonstraram que nas áreas já urbanizadas, o grau de impermeabilização e tempo de concentração das sub-bacias apresentaram  níveis considerados “médios e altos”, o que é preocupante, devido a relação dessas variáreis ao crescimento das vazões e volume escoado, e, consequentemente, aumento da frequência de inundações. Medidas não-estruturais, como legislação de uso do solo, com regras e incentivo para aumento de áreas permeáveis em lotes, bem como implantação de soluções alternativas de drenagem urbana que promovam o retardamento das águas pluviais, são soluções que podem ser implementadas na área em estudo.Analysis of the waterproofing rate and time of concentration in urban sub-basins of Barra do Garças – MT, Pontal do Araguaia – MT e Aragarças – GOAbstract: This study aimed to verify the waterproofing rates and time of concentration of these sub-basins present in the urban area of Barra do Garças – MT, Pontal do Araguaia – MT e Aragarças – GO. Such variables can assist in land use of urban expansion and the urban planning of these cities. The results demonstrated that in urban areas already, the degree of waterproofing and time of concentration of the sub-basins presented levels considered "medium and high", which is worrying, because the relationship of these variables to the growth of flows and runoff, and, consequently, increased frequency of floods. Non-structural measures such as land use legislation, with rules and incentive to increase permeable areas on lots, and implementation of alternative solutions to urban drainage that promote the

Eutrophication in the Yunnan Plateau lakes: the influence of lake morphology, watershed land use, and socioeconomic factors.

Science.gov (United States)

Liu, Wenzhi; Li, Siyue; Bu, Hongmei; Zhang, Quanfa; Liu, Guihua

2012-03-01

Lakes play an important role in socioeconomic development and ecological balance in China, but their water quality has deteriorated considerably in recent decades. In this study, we investigated the spatial-temporal variations of eutrophication parameters (secchi depth, total nitrogen, total phosphorus, chemical oxygen demand, chlorophyll-a, trophic level index, and trophic state index) and their relationships with lake morphology, watershed land use, and socioeconomic factors in the Yunnan Plateau lakes. Results indicated that about 77.8% of lakes were eutrophic according to trophic state index. The plateau lakes showed spatial variations in water quality and could be classified into high-nutrient and low-nutrient groups. However, because watersheds were dominated by vegetation, all eutrophication parameters except chlorophyll-a showed no significant differences between the wet and dry seasons. Lake depth, water residence time, volume, and percentage of built-up land were significantly related to several eutrophication parameters. Agricultural land use and social-economic factors had no significant correlation with all eutrophication parameters. Stepwise regression analyses demonstrated that lake depth and water residence time accounted for 73.8% to 87.6% of the spatial variation of single water quality variables, respectively. Redundancy analyses indicated that lake morphology, watershed land use, and socioeconomic factors together explained 74.3% of the spatial variation in overall water quality. The results imply that water quality degradation in the plateau lakes may be mainly due to the domestic and industrial wastewaters. This study will improve our understanding of the determinants of lake water quality and help to design efficient strategies for controlling eutrophication in the plateau region.

75 FR 6354 - NOAA Great Lakes Habitat Restoration Program Project Grants under the Great Lakes Restoration...

Science.gov (United States)

2010-02-09

...-04] RIN 0648-ZC10 NOAA Great Lakes Habitat Restoration Program Project Grants under the Great Lakes... Atmospheric Administration (NOAA), Department of Commerce. ACTION: Notice of funding availability; Date... on January 19, 2010. That notice announced the NOAA Great Lakes Habitat Restoration Program Project...

Clearing lakes : an ecosystem approach to the restoration and management of shallow lakes in the Netherlands

NARCIS (Netherlands)

Hosper, H.

1997-01-01

In the 1950 s and 1960 s, most shallow lakes in the Netherlands shifted from macrophyte-dominated clear water lakes, towards algae-dominated turbid water lakes. Eutrophication, i.e. increased nutrient loading, is the main cause of the deterioration

Microplastics in surface waters of Dongting Lake and Hong Lake, China.

Science.gov (United States)

Wang, Wenfeng; Yuan, Wenke; Chen, Yuling; Wang, Jun

2018-08-15

Microplastics pollution is an environmental issue of increasing concern. Much work has been done on the microplastics pollution in the marine environments. Although freshwaters are potential sources and transport pathways of plastic debris to the oceans, there is a lack of knowledge regarding the presence of microplastics in freshwater systems, especially in China, the world's largest producer of plastics. This study investigated the occurrence and properties of microplastics in surface waters of two important lakes in the middle reaches of the Yangtze River. The concentration ranges of microplastics in Dongting Lake and Hong Lake were 900-2800 and 1250-4650n/m 3 , respectively. Fiber was the dominant shape. Colored items occupied the majority. Particles with a size of 20% of total microplastics collected in both lakes. Most of the selected particles were identified as plastics, with polyethylene (PE) and polypropylene (PP) being the major components. This study can provide valuable reference for better understanding the microplastics pollution in inland freshwater ecosystems. Copyright © 2018 Elsevier B.V. All rights reserved.

Evaluation of Water Quality in Shallow Lakes, Case Study of Lake Uluabat

Directory of Open Access Journals (Sweden)

Saadet İLERİ

2014-04-01

Full Text Available Lake Uluabat, located 20 km south of the Marmara Sea, between 42° 12' North latitude, 28° 40'East longitude and is located in the province of Bursa. The Lake is one of the richest lakes in terms of aquatic plants besides fish and bird populations in Turkey. In this study, water quality of the Lake was monitored from June 2008 to May 2009 during the 12 month period with the samples taken from 8 points in the lake and spatial and temporal variations of the parameters were examined. pH, temperature (T, electrical conductivity (EC, dissolved oxygen (DO, suspended solids (SS, secchi depth (SD, water level (WL, nitrate nitrogen (NO3-N, total nitrogen (TN, phosphate-phosphorus (PO4-P, total phosphorus (TP, alkalinity, chemical oxygen demand (COD and chlorophyll-a (Chl-a were the monitoring parameters. As a result, concentrations of the parameters were found at high levels especially the 1st, 4th, 5th, and 8th stations and temporally were found at high levels often in the summer. According to the results of analysis of variance, regional and temporal variations of all parameters were found important except SS and NO3-N

Does lake size matter? Combining morphology and process modeling to examine the contribution of lake classes to population-scale processes

Science.gov (United States)

Winslow, Luke A.; Read, Jordan S.; Hanson, Paul C.; Stanley, Emily H.

2014-01-01

With lake abundances in the thousands to millions, creating an intuitive understanding of the distribution of morphology and processes in lakes is challenging. To improve researchers’ understanding of large-scale lake processes, we developed a parsimonious mathematical model based on the Pareto distribution to describe the distribution of lake morphology (area, perimeter and volume). While debate continues over which mathematical representation best fits any one distribution of lake morphometric characteristics, we recognize the need for a simple, flexible model to advance understanding of how the interaction between morphometry and function dictates scaling across large populations of lakes. These models make clear the relative contribution of lakes to the total amount of lake surface area, volume, and perimeter. They also highlight the critical thresholds at which total perimeter, area and volume would be evenly distributed across lake size-classes have Pareto slopes of 0.63, 1 and 1.12, respectively. These models of morphology can be used in combination with models of process to create overarching “lake population” level models of process. To illustrate this potential, we combine the model of surface area distribution with a model of carbon mass accumulation rate. We found that even if smaller lakes contribute relatively less to total surface area than larger lakes, the increasing carbon accumulation rate with decreasing lake size is strong enough to bias the distribution of carbon mass accumulation towards smaller lakes. This analytical framework provides a relatively simple approach to upscaling morphology and process that is easily generalizable to other ecosystem processes.

International Planning for Subglacial Lake Exploration

Science.gov (United States)

Kennicutt, M.; Priscu, J.

2003-04-01

As one of the last unexplored frontiers on our planet, subglacial lakes offer a unique and exciting venue for exploration and research. Over the past several years, subglacial lakes have captured the imagination of the scientific community and public, evoking images of potential exotic life forms surviving under some of the most extreme conditions on earth. Various planning activities have recognized that due to the remote and harsh conditions, that a successful subglacial lake exploration program will entail a concerted effort for a number of years. It will also require an international commitment of major financial and human resources. To begin a detailed planning process, the Scientific Committee on Antarctic Research (SCAR) convened the Subglacial Antarctic Lake Exploration Group of Specialists (SALEGOS) in Tokyo in 2000. The group was asked to build on previous workshops and meetings to develop a plan to explore subglacial lake environments. Its mandate adopted the guiding principles as agreed in Cambridge in 1999 that the program would be interdisciplinary in scope, be designed for minimum contamination and disturbance of the subglacial lake environment, have as a goal lake entry and sample retrieval, and that the ultimate target of the program should be Lake Vostok exploration. Since its formation SALEGOS has met three times and addressed some of the more intractable issues related to subglacial lake exploration. Topics under discussion include current state-of-the-knowledge of subglacial environments, technological needs, international management and organizational strategies, a portfolio of scientific projects, "clean" requirements, and logistical considerations. In this presentation the actvities of SALEGOS will be summarized and recommendations for an international subglacial lake exploration program discussed.

Genetic diversity of wild and hatchery lake trout populations: Relevance for management and restoration in the Great Lakes

Science.gov (United States)

Page, K.S.; Scribner, K.T.; Burnham-Curtis, M.

2004-01-01

The biological diversity of lake trout Salvelinus namaycush in the upper Great Lakes was historically high, consisting of many recognizable morphological types and discrete spawning populations. During the 1950s and 1960s, lake trout populations were extirpated from much of the Great Lakes primarily as a result of overfishing and predation by the parasitic sea lamprey Petromyzon marinus. Investigations of how genetic diversity is partitioned among remnant wild lake trout populations and hatchery broodstocks have been advocated to guide lake trout management and conservation planning. Using microsatellite genetic markers, we estimated measures of genetic diversity and the apportionment of genetic variance among 6 hatchery broodstocks and 10 wild populations representing three morphotypes (lean, humper, and siscowet). Analyses revealed that different hatchery broodstocks and wild populations contributed disproportionally to the total levels of genetic diversity. The genetic affinities of hatchery lake trout reflected the lake basins of origin of the wild source populations. The variance in allele frequency over all sampled extant wild populations was apportioned primarily on the basis of morphotype (??MT = 0.029) and secondarily among geographically dispersed populations within each morphotype (??ST = 0.024). The findings suggest that the genetic divergence reflected in recognized morphotypes and the associated ecological and physiological specialization occurred prior to the partitioning of large proglacial lakes into the Great Lakes or as a consequence of higher contemporary levels of gene flow within than among morphotypes. Information on the relative contributions of different broodstocks to total gene diversity within the regional hatchery program can be used to prioritize the broodstocks to be retained and to guide future stocking strategies. The findings highlight the importance of ecological and phenotypic diversity in Great Lakes fish communities and

The Impact of Nutrient State and Lake Depth on Top-down Control in the Pelagic Zone of Lakes: A Study of 466 Lakes from the Temperate Zone to the Arctic

DEFF Research Database (Denmark)

Jeppesen, E.; Jensen, J. P.; Jensen, C.

2003-01-01

is unimodally related to TP and is highest in the most nutrient-rich and nutrient-poor lakes and generally higher in shallow than deep lakes, (b) the cascading effect of changes in predator control on phytoplankton decreases with increasing TP, and (c) these general patterns occur with significant variations......%, respectively, at all TP levels. Moreover, deep lakes (more than 6 m) had a higher percentage of Daphnia than shallow (less than 6 m) lakes. The median percentage of Daphnia peaked at 0.15 mg L-1 in shallow lakes and 0.09 mg L-1 in deep lakes. The assumption that fish are responsible for the unimodality...

Hydrograph Predictions of Glacial Lake Outburst Floods From an Ice-Dammed Lake

Science.gov (United States)

McCoy, S. W.; Jacquet, J.; McGrath, D.; Koschitzki, R.; Okuinghttons, J.

2017-12-01

Understanding the time evolution of glacial lake outburst floods (GLOFs), and ultimately predicting peak discharge, is crucial to mitigating the impacts of GLOFs on downstream communities and understanding concomitant surface change. The dearth of in situ measurements taken during GLOFs has left many GLOF models currently in use untested. Here we present a dataset of 13 GLOFs from Lago Cachet Dos, Aysen Region, Chile in which we detail measurements of key environmental variables (total volume drained, lake temperature, and lake inflow rate) and high temporal resolution discharge measurements at the source lake, in addition to well-constrained ice thickness and bedrock topography. Using this dataset we test two common empirical equations as well as the physically-based model of Spring-Hutter-Clarke. We find that the commonly used empirical relationships based solely on a dataset of lake volume drained fail to predict the large variability in observed peak discharges from Lago Cachet Dos. This disagreement is likely because these equations do not consider additional environmental variables that we show also control peak discharge, primarily, lake water temperature and the rate of meltwater inflow to the source lake. We find that the Spring-Hutter-Clarke model can accurately simulate the exponentially rising hydrographs that are characteristic of ice-dammed GLOFs, as well as the order of magnitude variation in peak discharge between events if the hydraulic roughness parameter is allowed to be a free fitting parameter. However, the Spring-Hutter-Clarke model over predicts peak discharge in all cases by 10 to 35%. The systematic over prediction of peak discharge by the model is related to its abrupt flood termination that misses the observed steep falling limb of the flood hydrograph. Although satisfactory model fits are produced, the range in hydraulic roughness required to obtain these fits across all events was large, which suggests that current models do not

Western Alaska ESI: LAKES (Lake Polygons)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains vector polygons representing lakes and land masses used in the creation of the Environmental Sensitivity Index (ESI) for Western Alaska. The...

Lake Roosevelt Fisheries Evaluation Program; Meadow Creek vs. Lake Whatcom Stock Kokanee Salmon Investigations in Lake Roosevelt, Annual Report 2002.

Energy Technology Data Exchange (ETDEWEB)

McLellan, Holly

2003-03-01

Lake Whatcom, Washington kokanee have been stocked in Lake Roosevelt since 1987 with the primary objective of creating a self-sustaining fishery. Success has been limited by low recruitment to the fishery, low adult returns to hatcheries, and a skewed sex ratio. It was hypothesized that a stock native to the upper Columbia River might perform better than the coastal Lake Whatcom stock. Kokanee from Meadow Creek, a tributary of Kootenay Lake, British Columbia were selected as an alternative stock. Post smolts from each stock were released from Sherman Creek Hatchery in late June 2000 and repeated in 2001. Stock performance was evaluated using three measures; (1) number of returns to Sherman Creek, the primary egg collection facility, (2) the number of returns to 86 tributaries sampled and, (3) the number of returns to the creel. In two repeated experiments, neither Meadow Creek or Lake Whatcom kokanee appeared to be capable of providing a run of three-year old spawners to sustain stocking efforts. Less than 10 three-years olds from either stock were collected during the study period. Chi-square analysis indicated age two Meadow Creek kokanee returned to Sherman Creek and to other tributaries in significantly higher numbers when compared to the Lake Whatcom stock in both 2000 and 2001. However, preliminary data from the Spokane Tribe of Indians indicated that a large number of both stocks were precocial before they were stocked. The small number of hatchery three-year olds collected indicated that the current hatchery rearing and stocking methods will continue to produce a limited jacking run largely composed of precocious males and a small number of three-year olds. No kokanee from the study were collected during standard lake wide creel surveys. Supplemental creel data, including fishing derbies, test fisheries, and angler diaries, indicated anglers harvested two-year-old hatchery kokanee a month after release. The majority of the two-year old kokanee harvested

Dioctophyme renale: prevalence and risk factors of parasitism in dogs of São Cristóvão district, Três Barras county, Santa Catarina State, Brazil

Directory of Open Access Journals (Sweden)

Daniela Pedrassani

Full Text Available Abstract Dioctophyme renale is a nematode that can be found parasitizing the kidney, peritoneal cavity and, rarely, other organs of canids and mustelids. This disease has high occurrence in the municipality of Três Barras, state of Santa Catarina, thus making this an interesting area to study the epidemiological aspects of infection by D. renale in dogs. Among 197 dogs, 14.2% showed the parasite eggs in urine and 16.4% showed IgG antibodies anti-D. renale in serum samples according to the indirect ELISA method; among seropositive dogs, 15 (37.5% animals did not show any parasite eggs in their urine. Parasitism was more frequent in females, and there was no finding of interference from age on parasitism. Factors such as water potential and presence of paratenic hosts in the studied region were reported by the owners of dogs and may have contributed to the occurrence of parasitism.

The Brine Shrimp Artemia Survives in Diluted Water of Lake Bunyampaka, an Inland Saline Lake in Uganda

Directory of Open Access Journals (Sweden)

Martin Sserwadda

2018-02-01

Full Text Available Ugandan aquaculture is in the process of development; however, it requires access to an affordable live food source, such as brine shrimp Artemia. This study fits within a broader feasibility study of domestic Artemia production in salt lakes. Since Uganda is a landlocked country, the only opportunity for live water food sources lies in the salt lakes in the west of the country. This study used saline water from one of these lakes, Lake Bunyampaka (salinity 72 mg L−1. Two Artemia strains, i.e., the Great Salt Lake strain, which is the dominant strain on the market, and the Vinh Chau strain, which is by far the most inoculated strain in the world, were assayed for their survival, growth, and reproduction in diluted Lake Bunyampaka water, using natural seawater as control. The organisms were fed live freshly cultured microalgae Tetraselmis suecica ad libitum. Our study revealed that the Vinh Chau strain performed especially well in Lake Bunyampaka water diluted to 50 g L−1. The data presented in this study generate the first useful information for the future inoculation of Artemia in Lake Bunyampaka in Uganda, and hence domestic Artemia production in the country; however, further larger-scale laboratory work, followed by field trials, is still needed.

A radical shift from soft-water to hard-water lake: palaeolimnological evidence from Lake Kooraste Kõverjärv, southern Estonia

Directory of Open Access Journals (Sweden)

Tiiu Alliksaar

2012-11-01

Full Text Available The Water Framework Directive (WFD of the European Union requires the quality of all European water bodies to be examined, and aims to achieve good status by 2015. This study was initiated to assess whether a potential reference lake for identifying lake-type specific reference conditions meets the WFD requirements, of being minimally impacted by human activity during the last centuries. The sediments of Lake Kooraste Kõverjärv were analysed for diatom assemblages and sediment composition; past changes in the lake-water pH and total phosphorus were reconstructed, using quantitative models on sedimentary diatoms. The chronology of sediments was established, using spheroidal fly-ash particles stratigraphy. Palaeolimnological investigations, supported by information from historical maps, revealed that man-made changes around the lake have severely influenced its ecological conditions. The lake, which had been oligotrophic with soft and clear water before the mid-17th century, has been trans­formed into a hard-water lake by modifications to the inflow and outflow. The lake water quality has also been altered by the infiltration of nutrients from a nearby hypertrophic lake that was used for flax retting since the 19th century. Although the ecological status of the lake has remained good despite all these changes, it is still questionable whether to nominate it as a reference lake for stratified hard-water lake types.

Changes in ice cover thickness and lake level of Lake Hoare, Antarctica - Implications for local climatic change

Science.gov (United States)

Wharton, Robert A., Jr.; Mckay, Christopher P.; Clow, Gary D.; Andersen, Dale T.; Simmons, George M., Jr.; Love, F. G.

1992-01-01

Results are reported from 10 years of ice-thickness measurements at perennially ice-covered Lake Hoare in southern Victoria Land, Antarctica. The ice cover of this lake had been thinning steadily at a rate exceeding 20 cm/yr during the last decade but seems to have recently stabilized at a thickness of 3.3 m. Data concerning lake level and degree-days above freezing are presented to show the relationship between peak summer temperatures and the volume of glacier-derived meltwater entering Lake Hoare each summer. From these latter data it is inferred that peak summer temperatures have been above 0 C for a progressively longer period of time each year since 1972. Possible explanations for the thinning of the lake ice are considered. The thickness of the ice cover is determined by the balance between freezing during the winter and ablation that occurs all year but maximizes in summer. It is suggested that the term most likely responsible for the change in the ice cover thickness at Lake Hoare is the extent of summer melting, consistent with the rising lake levels.

Restoring life to acidified lakes

Energy Technology Data Exchange (ETDEWEB)

Shepard, M

1986-05-01

In 1983 EPRI initiated the lake acidification mitigation project (LAMP) in order to examine the long-term ecosystem effects of liming lakes, and to develop a model for calculating optimal liming doses. Investigations were carried out at lakes under 3 sets of conditions: reacidification, maintenance liming and preventive maintenance liming. The research so far has indicated that liming is a safe and effective technique.

Assessing Lake Level Variability and Water Availability in Lake Tana, Ethiopia using a Groundwater Flow Model and GRACE Satellite Data

Science.gov (United States)

Hasan, E.; Dokou, Z.; Kirstetter, P. E.; Tarhule, A.; Anagnostou, E. N.; Bagtzoglou, A. C.; Hong, Y.

2017-12-01

Lake Tana is the source of the Blue Nile and Ethiopia's largest natural buffer against seasonal variations of rainfall. Assessing the interactions between the lake level fluctuation, hydroclimatic variabilities and anthropogenic factors is essential to detect drought conditions and identify the role of human management in controlling the Lake water balance. Via an extended record of Total Water Storage (TWS) anomalies for the period 1960-2016, a water budget model for the lake water inflow/outflow was developed. Estimates of Lake Level Altimetry (LLA) based on in-situ and satellite altimetry were composited from 1960-2016 and compared to the extended TWS anomalies, the self-calibrated Palmer Drought Severity Index (scPDSI), the El Niño Southern Oscillation (ENSO) and the historical lake water levels and releases. In addition, the simulated lake levels and water budget from a coupled groundwater and lake model of the Lake Tana basin were compared to the above results. Combining the different approaches, the water budget of the lake can be monitored, the drought conditions can be identified and the role of human management in the lake can be determined. For instance, three major drought periods are identified, 1970 to 1977, 1979 to 1987 and 1990 to 1998, each succeeded with an interposed flooding related recovery year, i.e. 1978, 1988 and 1999. The drought/flooding events were attributed mainly to the ENSO interactions that resulted in lake level fluctuations. The period from 2002-2006 was associated with a remarkable decline of the lake level that was attributed partly in drought conditions and the full flow regulation of the Chara Chara weir at the lake outlet, initiated in 2001.

Paleoenvironments, Evolution, and Geomicrobiology in a Tropical Pacific Lake: The Lake Towuti Drilling Project (TOWUTI)

Science.gov (United States)

Vogel, Hendrik; Russell, James M.; Bijaksana, Satria; Crowe, Sean; Fowle, David; Haffner, Douglas; King, John; Marwoto, Ristiyanti; Melles, Martin; von Rintelen, Thomas; Stevenson, Janelle; Watkinson, Ian; Wattrus, Nigel

2014-05-01

Lake Towuti (2.5°S, 121°E) is a, 560 km2, 200-m deep tectonic lake at the downstream end of the Malili lake system, a set of five, ancient (1-2 MYr) tectonic lakes in central Sulawesi, Indonesia. Lake Towuti's location in central Indonesia provides a unique opportunity to reconstruct long-term paleoclimate change in a crucially important yet understudied region- the Indo-Pacific warm pool (IPWP), heart of the El Niño-Southern Oscillation. The Malili Lakes have extraordinarily high rates of floral and faunal endemism, and the lakes are surrounded by one of the most diverse tropical forests on Earth. Drilling in Lake Towuti will identify the age and origin of the lake and the environmental and climatic context that shaped the evolution of this unique lacustrine and terrestrial ecosystem. The ultramafic (ophiolitic) rocks and lateritic soils surrounding Lake Towuti provide metal substrates that feed a diverse, exotic microbial community, analogous to the microbial ecosystems that operated in the Archean Oceans. Drill core will provide unique insight into long-term changes in this ecosystem, as well as microbial processes operating at depth in the sediment column. High-resolution seismic reflection data (CHIRP and airgun) combined with numerous long sediment piston cores collected from 2007-2013 demonstrate the enormous promise of Lake Towuti for an ICDP drilling campaign. Well-stratified sequences of up to 150 m thickness, uninterrupted by unconformities or erosional truncation, are present in multiple sub-basins within Towuti, providing ideal sites for long-term environmental, climatic, and limnological reconstructions. Multiproxy analyses of our piston cores document a continuous and detailed record of moisture balance variations in Lake Towuti during the past 60 kyr BP. In detail our datasets show that wet conditions and rainforest ecosystems in central Indonesia persisted during Marine Isotope Stage 3 (MIS3) and the Holocene, and were interrupted by severe

Review Article: Lake and breach hazard assessment for moraine-dammed lakes: an example from the Cordillera Blanca (Peru

Directory of Open Access Journals (Sweden)

A. Emmer

2013-06-01

Full Text Available Glacial lake outburst floods (GLOFs and related debris flows represent a significant threat in high mountainous areas across the globe. It is necessary to quantify this threat so as to mitigate their catastrophic effects. Complete GLOF hazard assessment incorporates two phases: the probability of water release from a given glacial lake is estimated through lake and breach hazard assessment while the endangered areas are identified during downstream hazard assessment. This paper outlines a number of methods of lake and breach hazard assessment, which can be grouped into three categories: qualitative, of which we outline eight; semi-quantitative, of which we outline two; and quantitative, of which we outline three. It is considered that five groups of critical parameters are essential for an accurate regionally focused hazard assessment method for moraine-dammed lakes in the Cordillera Blanca. These comprise the possibility of dynamic slope movements into the lake, the possibility of a flood wave from a lake situated upstream, the possibility of dam rupture following a large earthquake, the size of the dam freeboard (or ratio of dam freeboard, and a distinction between natural dams and those with remedial work. It is shown that none of the summarised methods uses all these criteria with, at most, three of the five considered by the outlined methods. A number of these methods were used on six selected moraine-dammed lakes in the Cordillera Blanca: lakes Quitacocha, Checquiacocha, Palcacocha, Llaca, Rajucolta, and Tararhua. The results have been compared and show that each method has certain advantages and disadvantages when used in this region. These methods demonstrate that the most hazardous lake is Lake Palcacocha.

Technologies for lake restoration

Directory of Open Access Journals (Sweden)

Helmut KLAPPER

2003-09-01

Full Text Available Lakes are suffering from different stress factors and need to be restored using different approaches. The eutrophication remains as the main water quality management problem for inland waters: both lakes and reservoirs. The way to curb the degradation is to stop the nutrient sources and to accelerate the restoration with help of in-lake technologies. Especially lakes with a long retention time need (eco- technological help to decrease the nutrient content in the free water. The microbial and other organic matter from sewage and other autochthonous biomasses, causes oxygen depletion, which has many adverse effects. In less developed countries big reservoirs function as sewage treatment plants. Natural aeration solves problems only partly and many pollutants tend to accumulate in the sediments. The acidification by acid rain and by pyrite oxidation has to be controlled by acid neutralizing technologies. Addition of alkaline chemicals is useful only for soft waters, and technologies for (microbial alkalinization of very acidic hardwater mining lakes are in development. The corrective measures differ from those in use for eutrophication control. The salinization and water shortage mostly occurs if more water is used than available. L. Aral, L. Tschad, the Dead Sea or L. Nasser belong to waters with most severe environmental problems on a global scale. Their hydrologic regime needs to be evaluated. The inflow of salt water at the bottom of some mining lakes adds to stability of stratification, and thus accumulation of hydrogen sulphide in the monimolimnion of the meromictic lakes. Destratification, which is the most used technology, is only restricted applicable because of the dangerous concentrations of the byproducts of biological degradation. The contamination of lakes with hazardous substances from industry and agriculture require different restoration technologies, including subhydric isolation and storage, addition of nutrients for better self

Limnology of Eifel maar lakes

National Research Council Canada - National Science Library

Scharf, Burkhard W; Björk, Sven

1992-01-01

... : Species composition & seasonal periodicity - Qualitative & quantitative investigations on cladoceran zooplankton of oligotrophic maar lakes - Population dynamics of pelagic copepods in maar lakes - Population dynamics...

Comparative limnology of strip-mine lakes

Energy Technology Data Exchange (ETDEWEB)

Parsons, J D

1964-01-01

Lakes were classified according to chemical properties. The concentration of the ferric iron oxides was responsible for a reddish-black turbidity which, in turn, played a major role in the thermal stratification of red strip-mine lakes. Owing to the lack of measurable turbidity and as a result of selective absorption of visible solar radiation, other strip-mine lakes appeared blue in color. The annual heat budget and the summer heat budget are essentially equivalent under saline conditions. Regardless of the physical and chemical conditions of the strip-mine lakes, heat income was a function of the circulating water mass. The progressive oxidation and precipitation of the iron oxides is the key to the classification of strip-mine lakes.

Predicting the effects of climate change on trophic status of three morphologically varying lakes: Implications for lake restoration and management

DEFF Research Database (Denmark)

Trolle, Dennis; Hamilton, David P.; Pilditch, Conrad A.

2011-01-01

To quantify the effects of a future climate on three morphologically different lakes that varied in trophic status from oligo-mesotrophic to highly eutrophic, we applied the one-dimensional lake ecosystem model DYRESM-CAEDYM to oligo-mesotrophic Lake Okareka, eutrophic Lake Rotoehu, both in the t....... Therefore, future climate effects should be taken into account in the long-term planning and implementation of lake management as strategies may need to be refined and adapted to preserve or improve the present-day lake water quality....

Ecology of Meromictic Lakes

NARCIS (Netherlands)

Gulati, R.D.; Zadereev, E.S.; Degermendzhy, A.G.

2017-01-01

This volume presents recent advances in the research on meromictic lakes and a state-of-the art overview of this area. After an introduction to the terminology and geographic distribution of meromictic lakes, three concise chapters describe their physical, chemical and biological features. The

Lake water quality: Chapter 4 in A synthesis of aquatic science for management of Lakes Mead and Mohave

Science.gov (United States)

Tietjen, Todd; Holdren, G. Chris; Rosen, Michael R.; Veley, Ronald J.; Moran, Michael J.; Vanderford, Brett; Wong, Wai Hing; Drury, Douglas D.

2012-01-01

Given the importance of the availability and quality of water in Lake Mead, it has become one of the most intensely sampled and studied bodies of water in the United States. As a result, data are available from sampling stations across the lake (fig. 4-1 and see U.S. Geological Survey Automated Water-Quality Platforms) to provide information on past and current (2012) water-quality conditions and on invasive species that influence—and are affected by—water quality. Water quality in Lakes Mead and Mohave generally exceeds standards set by the State of Nevada to protect water supplies for public uses: drinking water, aquatic ecosystem health, recreation, or agricultural irrigation. In comparison to other reservoirs studied by the U.S. Environmental Protection Agency (USEPA) for a national lake assessment (U.S. Environmental Protection Agency, 2010), Lake Mead is well within the highest or ‘good’ category for recreation and aquatic health (see U.S. Environmental Protection Agency National Lakes Assessment and Lake Mead for more details). While a small part of the lake, particularly Las Vegas Bay, is locally influenced by runoff from urbanized tributaries such as Las Vegas Wash, contaminant loading in the lake as a whole is low compared to other reservoirs in the nation, which are influenced by runoff from more heavily urbanized watersheds (Rosen and Van Metre, 2010).

Changes in lake levels, salinity and the biological community of Great Salt Lake (Utah, USA), 1847-1987

Science.gov (United States)

Stephens, D.W.

1990-01-01

Great Salt Lake is the fourth largest terminal lake in the world, with an area of about 6000 square kilometers at its historic high elevation. Since its historic low elevation of 1277.52 meters in 1963, the lake has risen to a new historic high elevation of 1283.77 meters in 1986-1987, a net increase of about 6.25 meters. About 60 percent of this increase, 3.72 meters, has occurred since 1982 in response to greater than average precipitation and less than average evaporation. Variations in salinity have resulted in changes in the composition of the aquatic biological community which consists of bacteria, protozoa, brine shrimp and brine flies. These changes were particularly evident following the completion of a causeway in 1959 which divided the lake. Subsequent salinities in the north part of the lake have ranged from 16 to 29 percent and in the south part from 6 to 28 percent. Accompanying the rise in lake elevation from 1982 to 1987 have been large decreases in salinity of both parts of the lake. This has resulted in changes in the biota from obligate halophiles, such as Dunaliella salina and D. viridis, to opportunistic forms such as a blue-green alga (Nodularia spumigena). The distribution and abundance of brine shrimp (Artemia salina) in the lake also have followed closely the salinity. In 1986, when the salinity of the south part of the lake was about 6 percent, a population of brackish-water killifish (Lucania parva) was observed along the shore near inflow from a spring. ?? 1990 Kluwer Academic Publishers.

Lake Chapala change detection using time series

Science.gov (United States)

López-Caloca, Alejandra; Tapia-Silva, Felipe-Omar; Escalante-Ramírez, Boris

2008-10-01

The Lake Chapala is the largest natural lake in Mexico. It presents a hydrological imbalance problem caused by diminishing intakes from the Lerma River, pollution from said volumes, native vegetation and solid waste. This article presents a study that allows us to determine with high precision the extent of the affectation in both extension and volume reduction of the Lake Chapala in the period going from 1990 to 2007. Through satellite images this above-mentioned period was monitored. Image segmentation was achieved through a Markov Random Field model, extending the application towards edge detection. This allows adequately defining the lake's limits as well as determining new zones within the lake, both changes pertaining the Lake Chapala. Detected changes are related to a hydrological balance study based on measuring variables such as storage volumes, evapotranspiration and water balance. Results show that the changes in the Lake Chapala establish frail conditions which pose a future risk situation. Rehabilitation of the lake requires a hydrologic balance in its banks and aquifers.

The food of the lake trout (Cristivomer namaycush namaycush) and of the lawyer (Lota maculosa) of Lake Michigan

Science.gov (United States)

Van Oosten, John; Deason, Hilary J.

1938-01-01

This paper reports on a qualitative and quantitative analysis of the contents of 4,979 lake trout stomachs (593 examined in 1930 and 1,253 collected in 1931 from southern Lake Michigan, 1,446 from northern Lake Michigan and 1,687 from Green Bay in 1932), and of a total of 1,528 lawyer stomachs (172 examined in 1930 and 734 collected in 1931 from southern Lake Michigan, 612 from northern Lake Michigan and 10 from Green Bay in 1932). The food of the trout consisted of 98 per cent by volume of fish of which Cottidae and Coregonidae were the principal constituents. Cottidae were dominant in southern Lake Michigan (72 per cent by volume), Coregonidae in northern Lake Michigan (51 per cent) but the lake shiner, Notropis atherinides, was most important in Green Bay in the spring of the year (64 per cent). The lawyer food consisted of 74 per cent by volume of fish and 26 per cent invertebrates. Dominant items were Cottidae (76 per cent by volume) in southern Lake Michigan, Coregonidae (51 per cent) and Pontoporeia (37 per cent) in northern Lake Michigan, and Percopsis (34 per cent) and Mysis (26 per cent) in Green Bay. Data are also presented on the frequency of occurrence (number of stomachs) of the food items and its variation with the sizes of the trout and lawyers, depths of water, seasons, and localities; on the number of individual fish of each species destroyed by the trout and lawyers; and on the calculated volume of the food fishes preceding digestion. The lake trout and lawyer are competitors for the same food, are both predators of the commercially important Coregonidae, and the lawyer through its consumption of invertebrates is a food competitor of the Coregonidae.

Mirror Lake: Past, present and future: Chapter 6

Science.gov (United States)

Likens, Gene E.; LaBaugh, James W.; Winter, Thomas C.; Likens, Gene E.

2009-01-01

This chapter discusses the hydrological and biogeochemical characteristics of Mirror Lake and the changes that resulted from air-land-water interactions and human activities. Since the formation of Mirror Lake, both the watershed and the lake have undergone many changes, such as vegetation development and basin filling. These changes are ongoing, and Mirror Lake is continuing along an aging pathway and ultimately, it will fill with sediment and no longer be a lake. The chapter also identifies major factors that affected the hydrology and biogeochemistry of Mirror Lake: acid rain, atmospheric deposition of lead and other heavy metals, increased human settlement around the lake, the construction of an interstate highway through the watershed of the Northeast Tributary, the construction of an access road through the West and Northeast watersheds to the lake, and climate change. The chapter also offers future recommendations for management and protection of Mirror Lake.

Hydrogeologic setting, water budget, and preliminary analysis of ground-water exchange at Lake Starr, a seepage lake in Polk County, Florida

Science.gov (United States)

Swancar, Amy; Lee, T.M.; O'Hare, T. M.

2000-01-01

Lake Starr, a 134-acre seepage lake of multiple-sinkhole origin on the Lake Wales Ridge of central Florida, was the subject of a detailed water-budget study from August 1996 through July 1998. The study monitored the effects of hydrogeologic setting, climate, and ground-water pumping on the water budget and lake stage. The hydrogeologic setting of the Lake Starr basin differs markedly on the two sides of the lake. Ground water from the surficial aquifer system flows into the lake from the northwest side of the basin, and lake water leaks out to the surficial aquifer system on the southeast side of the basin. Lake Starr and the surrounding surficial aquifer system recharge the underlying Upper Floridan aquifer. The rate of recharge to the Upper Floridan aquifer is determined by the integrity of the intermediate confining unit and by the downward head gradient between the two aquifers. On the inflow side of the lake, the intermediate confining unit is more continuous, allowing ground water from the surficial aquifer system to flow laterally into the lake. Beneath the lake and on the southeast side of the basin, breaches in the intermediate confining unit enhance downward flow to the Upper Floridan aquifer, so that water flows both downward and laterally away from the lake through the ground-water flow system in these areas. An accurate water budget, including evaporation measured by the energy-budget method, was used to calculate net ground-water flow to the lake, and to do a preliminary analysis of the relation of net ground-water fluxes to other variables. Water budgets constructed over different timeframes provided insight on processes that affect ground-water interactions with Lake Starr. Weekly estimates of net ground-water flow provided evidence for the occurrence of transient inflows from the nearshore basin, as well as the short-term effects of head in the Upper Floridan aquifer on ground-water exchange with the lake. Monthly water budgets showed the effects

Evidence of sound production by spawning lake trout (Salvelinus namaycush) in lakes Huron and Champlain

Science.gov (United States)

Johnson, Nicholas S.; Higgs, Dennis; Binder, Thomas R.; Marsden, J. Ellen; Buchinger, Tyler John; Brege, Linnea; Bruning, Tyler; Farha, Steve A.; Krueger, Charles C.

2018-01-01

Two sounds associated with spawning lake trout (Salvelinus namaycush) in lakes Huron and Champlain were characterized by comparing sound recordings to behavioral data collected using acoustic telemetry and video. These sounds were named growls and snaps, and were heard on lake trout spawning reefs, but not on a non-spawning reef, and were more common at night than during the day. Growls also occurred more often during the spawning period than the pre-spawning period, while the trend for snaps was reversed. In a laboratory flume, sounds occurred when male lake trout were displaying spawning behaviors; growls when males were quivering and parallel swimming, and snaps when males moved their jaw. Combining our results with the observation of possible sound production by spawning splake (Salvelinus fontinalis × Salvelinus namaycush hybrid), provides rare evidence for spawning-related sound production by a salmonid, or any other fish in the superorder Protacanthopterygii. Further characterization of these sounds could be useful for lake trout assessment, restoration, and control.

Climate Change Adaptation Decision Making for Glacial Lake Outburst Floods From Palcacocha Lake in Peru

Science.gov (United States)

Cuellar, A. D.; McKinney, D. C.

2014-12-01

Climate change has accelerated glacial retreat in high altitude glaciated regions of Peru leading to the growth and formation of glacier lakes. Glacial lake outburst floods (GLOF) are sudden events triggered by an earthquake, avalanche into the lake or other shock that causes a sudden outflow of water. These floods are catastrophic because of their sudden onset, the difficulty predicting them, and enormous quantity of water and debris rapidly flooding downstream areas. Palcacocha Lake in the Peruvian Andes has experienced accelerated growth since it burst in 1941 and threatens the major city of Huaraz and surrounding communities. Since the 1941 flood stakeholders have advocated for projects to adapt to the increasing threat posed by Palcacocha Lake. Nonetheless, discussions surrounding projects for Palcacocha have not included a rigorous analysis of the potential consequences of a flood, probability of an event, or costs of mitigation projects. This work presents the first step to rationally analyze the risks posed by Palcacocha Lake and the various adaptation projects proposed. In this work the authors use decision analysis to asses proposed adaptation measures that would mitigate damage in downstream communities from a GLOF. We use an existing hydrodynamic model of the at-risk area to determine how adaptation projects will affect downstream flooding. Flood characteristics are used in the HEC-FIA software to estimate fatalities and injuries from an outburst flood, which we convert to monetary units using the value of a statistical life. We combine the monetary consequences of a GLOF with the cost of the proposed projects and a diffuse probability distribution for the likelihood of an event to estimate the expected cost of the adaptation plans. From this analysis we found that lowering the lake level by 15 meters has the least expected cost of any proposal despite uncertainty in the effect of lake lowering on flooding downstream.

Identifying Watershed Regions Sensitive to Soil Erosion and Contributing to Lake Eutrophication—A Case Study in the Taihu Lake Basin (China)

Science.gov (United States)

Lin, Chen; Ma, Ronghua; He, Bin

2015-01-01

Taihu Lake in China is suffering from severe eutrophication partly due to non-point pollution from the watershed. There is an increasing need to identify the regions within the watershed that most contribute to lake water degradation. The selection of appropriate temporal scales and lake indicators is important to identify sensitive watershed regions. This study selected three eutrophic lake areas, including Meiliang Bay (ML), Zhushan Bay (ZS), and the Western Coastal region (WC), as well as multiple buffer zones next to the lake boundary as the study sites. Soil erosion intensity was designated as a watershed indicator, and the lake algae area was designated as a lake quality indicator. The sensitive watershed region was identified based on the relationship between these two indicators among different lake divisions for a temporal sequence from 2000 to 2012. The results show that the relationship between soil erosion modulus and lake quality varied among different lake areas. Soil erosion from the two bay areas was more closely correlated with water quality than soil erosion from the WC region. This was most apparent at distances of 5 km to 10 km from the lake, where the r2 was as high as 0.764. Results indicate that soil erosion could be used as an indicator for identifying key watershed protection areas. Different lake areas need to be considered separately due to differences in geographical features, land use, and the corresponding effects on lake water quality. PMID:26712772

Identifying Watershed Regions Sensitive to Soil Erosion and Contributing to Lake Eutrophication--A Case Study in the Taihu Lake Basin (China).

Science.gov (United States)

Lin, Chen; Ma, Ronghua; He, Bin

2015-12-24

Taihu Lake in China is suffering from severe eutrophication partly due to non-point pollution from the watershed. There is an increasing need to identify the regions within the watershed that most contribute to lake water degradation. The selection of appropriate temporal scales and lake indicators is important to identify sensitive watershed regions. This study selected three eutrophic lake areas, including Meiliang Bay (ML), Zhushan Bay (ZS), and the Western Coastal region (WC), as well as multiple buffer zones next to the lake boundary as the study sites. Soil erosion intensity was designated as a watershed indicator, and the lake algae area was designated as a lake quality indicator. The sensitive watershed region was identified based on the relationship between these two indicators among different lake divisions for a temporal sequence from 2000 to 2012. The results show that the relationship between soil erosion modulus and lake quality varied among different lake areas. Soil erosion from the two bay areas was more closely correlated with water quality than soil erosion from the WC region. This was most apparent at distances of 5 km to 10 km from the lake, where the r² was as high as 0.764. Results indicate that soil erosion could be used as an indicator for identifying key watershed protection areas. Different lake areas need to be considered separately due to differences in geographical features, land use, and the corresponding effects on lake water quality.

Small-scale distribution and diel vertical migration of zooplankton in a shallow lake (Lake Naardermeer, the Netherlands)

NARCIS (Netherlands)

Cerbin, S.; Balayla, D.; Van de Bund, W.J.

2003-01-01

Small scale distribution and diurnal migration of zooplankton were investigated in lake Naardermeer, a shallow lake largely covered by uniform Chara beds. For sampling, pattern samplers with a number of inverted funnels facing towards the lake bottom and held in a frame were used. Samplers were

Ice formation in subglacial Lake Vostok, Central Antarctica

Science.gov (United States)

Souchez, R.; Petit, J. R.; Tison, J.-L.; Jouzel, J.; Verbeke, V.

2000-09-01

The investigation of chemical and isotopic properties in the lake ice from the Vostok ice core gives clues to the mechanisms involved in ice formation within the lake. A small lake water salinity can be reasonably deduced from the chemical data. Possible implications for the water circulation of Lake Vostok are developed. The characteristics of the isotopic composition of the lake ice indicate that ice formation in Lake Vostok occurred by frazil ice crystal generation due to supercooling as a consequence of rising waters and a possible contrast in water salinity. Subsequent consolidation of the developed loose ice crystals results in the accretion of ice to the ceiling of the lake.

Lake ecosystem response to climate change 8200 years ago. A multi-proxy study at Lake Højby Sø, Denmark

DEFF Research Database (Denmark)

Rasmussen, Peter; Hede, Mikkel Ulfeldt; Noe-Nygaard, Nanna

2009-01-01

of climate and the effects of human activities. These problems also complicate the prediction of possible future climate influence on lake ecology. A way of circumventing these problems is the use of lake sediment records which contain a wealth of information about past lake history over long time scales...... productivity as reflected by high algal pigment accumulation rates in the period c. 8400–7950 cal yr BP. After c. 7950 cal yr BP algal productivity declined somewhat but the lake did not return to its pre-8400 cal yr BP conditions remaining a more productive and nutrient rich lake than before the climate...... was of more importance for lake ecosystem process than the change in air temperature....

A Systematic Study of Zerbar Lake Restoration

Science.gov (United States)

Hosseini, Reza; Oveis Torabi, Seyed; Forman Asgharzadeh, Deonna

2017-04-01

The beautiful lake of Zerbar, located near Marivan City at the west of Iran, is a freshwater lake with an area of 20 km2 and average depth of 5 meters. The lake is created by regional tectonic activities and is mainly fed with natural spring water from bottom. During the past three decades, regional development has caused much disturbance to the natural environment of the lake and its watershed. Rescuing the lake is crucial to the sustainability of the whole region. The study of Zerbar Restoration was performed with the aim to restore its health indicators. Variety of human activities in the watershed, as well as the multidisciplinary nature of lake restoration studies, made it necessary to develop a systematic approach to conduct the study. In Step I of restoration studies, satellite images were investigated to identify the historical changes of watershed during the past 30 years. Meanwhile, documents since 50 years ago were studied. Results indicate that farmland and graze land areas have been relatively constant during the past 50 years. Also, the area of lake, its riparian canes and floating plants have not changed much. In fact, the only significant land use change observed was the significant spread of Marivan City that has stretched toward the lake. The main physical variation to the lake has been elevating the southern edge of the lake by a constructing a landfill dam which was done to control the lake's overflow discharge for irrigation of downstream farmland development. Step II consists of studies performed by disciplines of water resources, hydrogeology, water quality, wetland and watershed ecology, agriculture, animal farming and fishery. Study results indicate that eutrophication (TSL>100), mainly caused by sewage from Marivan City and the surrounding rural areas has been the main reason for lake ecosystem degradation. DPSIR framework, as a novel approach in lake restoration, was applied to synthesize the study results of different disciplines in a

A model for landscape development in terms of shoreline displacement, sediment dynamics, lake formation, and lake choke-up processes

International Nuclear Information System (INIS)

Brydsten, Lars

2006-12-01

This project expands on the study 'A mathematical model for lake ontogeny in terms of filling with sediments and macrophyte vegetation' published in SKB TR-04-09. As the title suggests, this older model focuses on lakes (existing and future lakes). This newer study extends the model to examine progress of terrestrial objects such as mires or arable land. Furthermore, this newer model could simulate progress of the areas close to the objects. These areas are divided according to their watershed boundaries. If two or more objects are situated along the same brook, the lower situated area is defined as its catchments minus the catchments of the closest higher situated object. The model encourages the study of an object situated in the sea from the time of deglaciation (c. 10,000 BP) to the time for the object due to positive shore displacement is situated on land or that a lake object has progressed to a wetland, however not longer than 18,000 AP. The model focuses on the object and its location in 100-year steps. The model is written in VisualBasic and is divided into two modules, a marine module and a lake module. The marine module deals with shoreline displacement, erosion and accumulation of postglacial fine-grained sediments and erosion of glacial clay. Inputs to the marine module are a digital elevation model (DEM), a digital map showing the extension of the objects and a marine quaternary map. The two maps are in raster formats with exactly the same formats (extension and cell sizes) as the DEM. For each time step the water depths at each pixel are calculated using a shore displacement equation. Next, the water depth changes due to sediment dynamics are calculated using the following rules; accumulation of fine-grained sediments are allowed if the pixel is situated within a future lake object; erosion of fine-grained sediment is allowed if the pixel is not within a future lake object and the marine quaternary map shows occurrence of postglacial sediments and

A model for landscape development in terms of shoreline displacement, sediment dynamics, lake formation, and lake choke-up processes

Energy Technology Data Exchange (ETDEWEB)

Brydsten, Lars [Umeaa University, Dept. of Ecology and Environmental Science (Sweden)

2006-12-15

This project expands on the study 'A mathematical model for lake ontogeny in terms of filling with sediments and macrophyte vegetation' published in SKB TR-04-09. As the title suggests, this older model focuses on lakes (existing and future lakes). This newer study extends the model to examine progress of terrestrial objects such as mires or arable land. Furthermore, this newer model could simulate progress of the areas close to the objects. These areas are divided according to their watershed boundaries. If two or more objects are situated along the same brook, the lower situated area is defined as its catchments minus the catchments of the closest higher situated object. The model encourages the study of an object situated in the sea from the time of deglaciation (c. 10,000 BP) to the time for the object due to positive shore displacement is situated on land or that a lake object has progressed to a wetland, however not longer than 18,000 AP. The model focuses on the object and its location in 100-year steps. The model is written in VisualBasic and is divided into two modules, a marine module and a lake module. The marine module deals with shoreline displacement, erosion and accumulation of postglacial fine-grained sediments and erosion of glacial clay. Inputs to the marine module are a digital elevation model (DEM), a digital map showing the extension of the objects and a marine quaternary map. The two maps are in raster formats with exactly the same formats (extension and cell sizes) as the DEM. For each time step the water depths at each pixel are calculated using a shore displacement equation. Next, the water depth changes due to sediment dynamics are calculated using the following rules; accumulation of fine-grained sediments are allowed if the pixel is situated within a future lake object; erosion of fine-grained sediment is allowed if the pixel is not within a future lake object and the marine quaternary map shows occurrence of postglacial

Morphometry and Lens of Eyes Bilih Fish (mystacoleucus padangensis, Bleeker) from Lake Toba, North Sumatra and Lake Singkarak, West Sumatra

Science.gov (United States)

Razak, A.

2018-04-01

This research has been carried out 2015. Bilih fish today need conservation and attention for sustainability. Habitat this fish is treated by human activities in Lake Singkarak, West Sumatera and Lake Toba in North Sumatera. The objectives of the research are describes morphometry of the body and relation with lens of eyes. The methods of the reasearch for measure all parts of surface body fish according www.fishbase.org. For measure and chemical composition of lens of eyes Bilih Fish (M. padangensis) are according Razak (2005). T he result of the research are indicated the size of morphology body Bilih Fish from Lake Toba and from Lake Singkarak is diffrent. Furthermore, diameter of lens is trend linier follow the growth of the body Bilih Fish from Lake Singkarak and Lake Toba. The chemical composition of lens of eyes Bilih Fish from Lake Singkarak contains Sulfur until 73.77% per 100 ppm, another substances like Calcium, Silicone, Magnesium, Phosporus 4.09%-4.83% per 100 ppm. The chemical composition of lens of eyes Bilih Fish from Lake Toba contains Sulfur only 50.08% per 100 ppm, another substances like Kalium, Calcium, Silicone, Magnesium, Phosporus 1.09%-10.43% per 100 ppm. Kalium substance only found in lens of eyes Bilih Fish from Lake Toba. As conclusion, morphometry body Bilih Fish from Lake Toba is bigger better than Bilih Fish from Lake Singkarak and chemical composition lens of eyes Bilih Fish from Lake Toba is influenced by environmental waters factors.

Feeding ecology of lake whitefish larvae in eastern Lake Ontario

Science.gov (United States)

Johnson, James H.; McKenna, James E.; Chalupnicki, Marc A.; Wallbridge, Tim; Chiavelli, Rich

2009-01-01

We examined the feeding ecology of larval lake whitefish (Coregonus clupeaformis) in Chaumont Bay, Lake Ontario, during April and May 2004-2006. Larvae were collected with towed ichthyoplankton nets offshore and with larval seines along the shoreline. Larval feeding periodicity was examined from collections made at 4-h intervals over one 24-h period in 2005. Inter-annual variation in diet composition (% dry weight) was low, as was spatial variation among collection sites within the bay. Copepods (81.4%), primarily cyclopoids (59.1%), were the primary prey of larvae over the 3-year period. Cladocerans (8.1%; mainly daphnids, 6.7%) and chironomids (7.3%) were the other major prey consumed. Larvae did not exhibit a preference for any specific prey taxa. Food consumption of lake whitefish larvae was significantly lower at night (i.e., 2400 and 0400 h). Substantial variation in diet composition occurred over the 24-h diel study. For the 24-h period, copepods were the major prey consumed (50.4%) and their contribution in the diet ranged from 29.3% (0400 h) to 85.9% (1200 h). Chironomids made up 33.4% of the diel diet, ranging from 8.0% (0800 h) to 69.9% (0400 h). Diel variation in the diet composition of lake whitefish larvae may require samples taken at several intervals over a 24-h period to gain adequate representation of their feeding ecology.

Variations of alkaline phosphatase activity and P fractions in sediments of a shallow Chinese eutrophic lake (Lake Taihu)

International Nuclear Information System (INIS)

Zhang Tingxi; Wang Xiaorong; Jin Xiangcan

2007-01-01

The distribution of alkaline phosphatase activity (APA) and P fractions in sediment cores and the relationship between them were studied in a shallow Chinese freshwater lake (Lake Taihu). Sediment cores were collected from four sites, characterized by different degrees of eutrophication in June 2004. Sediment P was fractionated into Fe/Al-P, Ca-P, organic P (OP), inorganic P (IP) and total P (TP). The former two species made the largest contribution to the sediment P pool. Results show that trophic status and hydrological conditions have great impact on the APA of the sediments. The order of the APA in sediments was conjectured to be: macrophyte dominated lake > transitional lake > algal dominated lake. APA profiles follow a similar downcore decreasing trend. There was a positive relationship between the APA and the TP, IP. The multiple linear regression equation of the APA and P fractions is: APA = -97 + 0.768TP - 0.985Fe/Al-P. - Characteristics of the alkaline phosphatase activity and P fractions in sediments of different trophic status lake were studied in Lake Taihu

Environmental Monitoring, Water Quality - Lakes Assessments - Attaining

Data.gov (United States)

NSGIC Education | GIS Inventory — This layer shows only attaining lakes of the Integrated List. The Lakes Integrated List represents lake assessments in an integrated format for the Clean Water Act...

Tides and lake-level variations in the great Patagonian lakes: Observations, modelling and geophysical implications.

Science.gov (United States)

Marderwald, Eric; Richter, Andreas; Horwath, Martin; Hormaechea, Jose Luis; Groh, Andreas

2016-04-01

In Patagonia, the glacial-isostatic adjustment (GIA) to past ice-mass changes (Ivins & James 2004; Klemann et al. 2007) is of particular interest in the context of the determination of the complex regional rheology related to plate subduction in a triple-junction constellation. To further complicate the situation, GIA is overlaid with load deformation not only due to present ice mass changes but also due to water-level changes in the lakes surrounding the icefields and the ocean surrounding Patagonia. These elastic deformations affect the determination of glacial-isostatic uplift rates from GPS observations (Dietrich et al. 2010; Lange et al. 2014). Observations of lake tides and their comparison with the theoretical tidal signal have been used previously to validate predictions of ocean tidal loading and have revealed regional deviations from conventional global elastic earth models (Richter et al. 2009). In this work we investigate the tides and lake-level variations in Lago Argentino, Lago Viedma, Lago San Martín/O'Higgins and Lago Buenos Aires/General Carrera. This allows us to test, among other things, the validity of tidal loading models. We present pressure tide-gauge records from two sites in Lago Argentino extending over 2.5 years (Richter et al. 2015). These observations are complemented by lake-level records provided by the Argentine National Hydrometeorological Network. Based on these lake-level time series the principal processes affecting the lake level are identified and quantified. Lake-level changes reflecting variations in lake volume are dominated by a seasonal cycle exceeding 1 m in amplitude. Lake-volume changes occur in addition with a daily period in response to melt water influx from surrounding glaciers. In Lago Argentino sporadic lake-volume jumps are caused by bursting of the ice dam of Perito Moreno glacier. Water movements in these lakes are dominated by surface seiches reaching 20 cm in amplitude. A harmonic tidal analysis of the lake

Pleistocene lake level changes in Western Mongolia

Science.gov (United States)

Borodavko, P. S.

2009-04-01

Global cooling in the Early Pleistocene caused extensive continental glaciation in the northern hemisphere including the arid areas of Central Asia. The reduction of temperatures (particularly summer temperatures) reduced evaporation and strengthened the importance of precipitation. The simultaneity of "lakes periods" (pluvials) and stages of glaciation is established experience confirmed by investigations in the west of North America and Russia. In the Mongolian Great Lakes Depression new evidence for similar conditions is found. The Great Lakes Depression is one of the largest in Central Asia, and is divided into 2 main Lakes basins: Hyargas Lake Basin and Uvs Lake Basin. The basin is 600-650 km in length with a width of 200-250 km in the north and 60-100 km in the south. Total catchment area is about 186600 km2. The elevation of the basin floor is from 1700 m a.s.l. to 760 m a.s.l., decreasing to the north and south-east. The depression extends south-north and is bounded by mountains: Tannu-Ola to the north, Hangai to the east; Gobi Altai to the south and Mongolian Altay to the west. The maximum elevation of the mountains is 4000 m a.s.l. There are some mountains with an elevation between 2000 and 3000 m a.s.l in the lake catchment. These mountains are not glaciated today. The geological record [1] suggests the Great Lakes Depression already existed in the Mesozoic, but assumed its modern form only during the Pliocene-Quaternary when tectonic movements caused the uplift of the surrounding mountains. A phase of tectonic stability occurred during the Late Quaternary. The depression is filled by Quaternary fluvial, aeolian and lacustrine deposits (e.g. sand, pebbles). The Neogene deposits are represented by coloured clay, marl, sand and sandstone [1]. Hyargas Lake is the end base level of erosion of the lake group consisting of the Hara-Us Nur, Dorgon, Hara Nur and Airag lakes. Hyargas is one of the largest lakes in Mongolia, with a water surface of 1,407 km2. The

The lakes of the Jordan Rift Valley

International Nuclear Information System (INIS)

Gat, J.R.

2001-01-01

This paper presents a summary of the proceedings of a workshop on the Lakes of the Jordan Rift Valley that was held in conjunction with the CRP on The Use of Isotope Techniques in Lake Dynamics Investigations. The paper presents a review of the geological, hydrogeological and physical limnological setting of the lakes in the Jordan Rift Valley, Lake Hula, Lake Kinneret and the Dead Sea. This is complemented by a description of the isotope hydrology of the system that includes the use of a wide range of isotopes: oxygen-18, deuterium, tritium, carbon-14, carbon-13, chlorine isotopes, boron-11 and helium-3/4. Environmental isotope aspects of the salt balances of the lakes, their palaeolimnology and biogeochemical tracers are also presented. The scope of application of isotopic tracers is very broad and provides a clear insight into many aspects of the physical, chemical and biological limnology of the Rift Valley Lakes. (author)

Successional change in the Lake Superior fish community: population trends in ciscoes, rainbow smelt, and lake trout, 1958-2008

Science.gov (United States)

Gorman, Owen T.

2012-01-01

The Lake Superior fish community underwent massive changes in the second half of the 20th century. Those changes are largely reflected in changes in abundance of the adults of principal prey species, the ciscoes (Coregonus spp.), the invasive rainbow smelt (Osmerus mordax), and the principal predator, lake trout (Salvelinus namaycush). To better understand changes in species abundances, a comprehensive series of gillnet and bottom trawl data collected from 1958 to 2008 were examined. In the late 1950s/early 1960s, smelt abundance was at its maximum, wild lake trout was at its minimum, and an abundance of hatchery lake trout was increasing rapidly. The bloater (Coregonus hoyi) was the prevalent cisco in the lake; abundance was more than 300% greater than the next most abundant cisco, shortjaw cisco (C. zenithicus), followed by kiyi (C. kiyi) and lake cisco (C. artedi). By the mid-1960s, abundance of hatchery lake trout was nearing maximum, smelt abundance was beginning to decline, and abundances of all ciscoes declined, but especially that of shortjaw cisco and kiyi. By the late 1970s, recovery of wild lake trout stocks was well underway and abundances of hatchery lake trout and smelt were declining and the ciscoes were reaching their nadir. During 1980–1990, the fish community underwent a dramatic shift in organization and structure. The rapid increase in abundance of wild lake trout, concurrent with a rapid decline in hatchery lake trout, signaled the impending recovery. Rainbow smelt abundance dropped precipitously and within four years, lake cisco and bloater populations rebounded on the heels of a series of strong recruitment events. Kiyi populations showed signs of recovery by 1989, and shortjaw by 2000, though well below historic maximum abundances. High abundance of adult smelt prior to 1980 appears to be the only factor linked to recruitment failure in the ciscoes. Life history traits of the cisco species were examined to better understand their different

Are all temperate lakes eutrophying in a warmer world?

Science.gov (United States)

Paltsev, A.; Creed, I. F.

2017-12-01

Freshwater lakes are at risk of eutrophication due to climate change and intensification of human activities on the planet. In relatively undisturbed areas of the temperate forest biome, lakes are "sentinels" of the effects of rising temperatures. We hypothesise that rising temperatures are driving a shift from nutrient-poor oligotrophic states to nutrient-rich eutrophic states. To test this hypothesis, we examined a time series of satellite based chlorophyll-a (a proxy of algal biomass) of 12,000+ lakes over 30 years in the Canadian portion of the Laurentian Great Lakes basin. From the time series, non-stationary trends (detected by Mann-Kendall analysis) and stationary cycles (revealed through Morlet wavelet analysis) were removed, and the standard deviation (SD) of the remaining residuals was used as an indicator of lake stability. Four classes of lake stability were identified: (1) stable (SD is consistently low); (2) destabilizing (SD increases over time); (3) unstable (SD is consistently high); and (4) stabilizing lakes (SD decreases over time). Stable lakes were either oligotrophic or eutrophic indicating the presence of two stable states in the region. Destabilizing lakes were shifting from oligotrophic to lakes with a higher trophic status (indicating eutrophication), unstable lakes were mostly mesotrophic, and stabilizing lakes were shifting from eutrophic to the lakes with lower trophic status (indicating oligotrophication). In contrast to common expectations, while many lakes (2142) were shifting from oligotrophic to eutrophic states, more lakes (3199) were showing the opposite trend and shifting from eutrophic to oligotrophic states. This finding reveals a complexity of lake responses to rising temperatures and the need to improve understanding of why some lakes shift while others do not. Future work is focused on exploring the interactive effects of global, regional, and local drivers of lake trophic states.

Basic limnology of fifty-one lakes in Costa Rica.

Science.gov (United States)

Haberyan, Kurt A; Horn, Sally P; Umaña, Gerardo

2003-03-01

We visited 51 lakes in Costa Rica as part of a broad-based survey to document their physical and chemical characteristics and how these relate to the mode of formation and geographical distribution of the lakes. The four oxbow lakes were low in elevation and tended to be turbid, high in conductivity and CO2, but low in dissolved O2; one of these, L. Gandoca, had a hypolimnion essentially composed of sea water. These were similar to the four wetland lakes, but the latter instead had low conductivities and pH, and turbidity was often due to tannins rather than suspended sediments. The thirteen artificial lakes formed a very heterogenous group, whose features varied depending on local factors. The thirteen lakes dammed by landslides, lava flows, or lahars occurred in areas with steep slopes, and were more likely to be stratified than most other types of lakes. The eight lakes that occupy volcanic craters tended to be deep, stratified, clear, and cool; two of these, L. Hule and L. Río Cuarto, appeared to be oligomictic (tending toward meromictic). The nine glacial lakes, all located above 3440 m elevation near Cerro Chirripó, were clear, cold, dilute, and are probably polymictic. Cluster analysis resulted in three significant groups of lakes. Cluster 1 included four calcium-rich lakes (average 48 mg l-1), Cluster 2 included fourteen lakes with more Si than Ca+2 and higher Cl- than the other clusters, and Cluster 3 included the remaining thirty-three lakes that were generally less concentrated. Each cluster included lakes of various origins located in different geographical regions; these data indicate that, apart from the high-altitude glacial lakes and lakes in the Miravalles area, similarity in lake chemistry is independent of lake distribution.

A imagem do destino turístico como ferramenta de diferenciação e promoção do turismo: Caso de Barra Grande/PI – Brasil

Directory of Open Access Journals (Sweden)

Marcelo Lima da Silva

2016-01-01

Full Text Available This paper analyzes the importance of the image of tourist destination at the beach of Barra Grande, located in Cajueiro da Praia/PI-Brazil. According to what was analyzed through the perception of tourists, it was possible to observe how this image formed by tourists is understood, along with the results and the corresponding factors that contributed to this image formation. This theme, which serves as a tool for differentiating and promoting tourism, in addition to intervene in the selection process, is essential to the instigation of the consumer to visit the destination. Thus, as the tourist product is intangible, it is proved through descriptions and pictures how important the imaginary image creation is, and what to do through the use of marketing strategies to reach a target audience. In such a way, the results were significant, which gave importance and value to the image of the destination studied.

Hydrological network and classification of lakes on the Third Pole

Science.gov (United States)

Gao, Yang; Wang, Weicai; Yao, Tandong; Lu, Ning; Lu, Anxin

2018-05-01

The intensity and form of changes in closed lakes, upstream lakes and outflow lakes on the Third Pole (TP) differ based on their drainage mode. Researchers' insufficient understanding of the hydrological networks associated with lakes hampers studies of the relationship between lakes and climate. In this study, we establish a comprehensive hydrological network for each lake (>1 km2) on the TP using 106 Landsat images, 236 Chinese topographic maps, and SRTM DEM. Three-hundred-ninety-seven closed lakes, 488 upstream lakes and 317 outflow lakes totaling 3,5498.49 km2, 7,378.82 km2, and 3,382.29 km2, respectively, were identified on the TP using 2010 data. Two-hundred-thirty-four closed lakes were found to not be linked to upstream lakes. The remaining 163 closed lakes were connected to and fed by the 488 upstream lakes. The object-oriented analyses within this study indicated that more rapid changes occurred in the surface extent of closed lakes than in upstream lakes or outflow lakes on the TP from 1970 s to 2010. Furthermore, the water volume of the examined closed lakes was almost nine times greater than that of the upstream lakes from 2003 to 2009. All the examined closed lakes exhibited an obvious water volume change compared to the corresponding upstream lakes in the same basin. Furthermore, two case studies illustrate that the annual and seasonal dynamics associated with the changes in closed lakes may reflect climate change patterns, while the upstream lake dynamics may be more controlled by the lakeshore terrain and drainage characteristics. The lake inventory and hydrological network catalogued in this study provide a basis for developing a better understanding of lake response to climate change on the TP.

Radioecological characteristics of Lake Zarnowieckie

International Nuclear Information System (INIS)

Soszka, G.J.; Grzybowska, D.; Rostek, J.; Pietruszewski, A.; Wardaszko, T.; Kalinowska, A.; Tomczak, J.

1986-01-01

Results are presented of the radioecological studies carried out in Lake Zarnowieckie as a part of pre-operational investigations related to the construction of a nuclear power station at this lake. Concentrations of essential radionuclides were determined in water, bottom sediments and selected plants and animals. Analyses were made of the distribution and spreading of 90 Sr and 137 Cs in the lake ecosystem and in the near-by meadows. 28 refs., 6 figs., 6 tabs. (author)

A mass balance mercury budget for a mine-dominated lake: Clear Lake, California

Science.gov (United States)

Suchanek, T.H.; Cooke, J.; Keller, K.; Jorgensen, S.; Richerson, P.J.; Eagles-Smith, Collin A.; Harner, E.J.; Adam, D.P.

2009-01-01

The Sulphur Bank Mercury Mine (SBMM), active intermittently from 1873–1957 and now a USEPA Superfund site, was previously estimated to have contributed at least 100 metric tons (105 kg) of mercury (Hg) into the Clear Lake aquatic ecosystem. We have confirmed this minimum estimate. To better quantify the contribution of the mine in relation to other sources of Hg loading into Clear Lake and provide data that might help reduce that loading, we analyzed Inputs and Outputs of Hg to Clear Lake and Storage of Hg in lakebed sediments using a mass balance approach. We evaluated Inputs from (1) wet and dry atmospheric deposition from both global/regional and local sources, (2) watershed tributaries, (3) groundwater inflows, (4) lakebed springs and (5) the mine. Outputs were quantified from (1) efflux (volatilization) of Hg from the lake surface to the atmosphere, (2) municipal and agricultural water diversions, (3) losses from out-flowing drainage of Cache Creek that feeds into the California Central Valley and (4) biotic Hg removal by humans and wildlife. Storage estimates include (1) sediment burial from historic and prehistoric periods (over the past 150–3,000 years) from sediment cores to ca. 2.5m depth dated using dichloro diphenyl dichloroethane (DDD), 210Pb and 14C and (2) recent Hg deposition in surficial sediments. Surficial sediments collected in October 2003 (11 years after mine site remediation) indicate no reduction (but a possible increase) in sediment Hg concentrations over that time and suggest that remediation has not significantly reduced overall Hg loading to the lake. Currently, the mine is believed to contribute ca. 322–331 kg of Hg annually to Clear Lake, which represents ca. 86–99% of the total Hg loading to the lake. We estimate that natural sedimentation would cover the existing contaminated sediments within ca. 150–300 years.

Uniformidade de deposição da calda de pulverização de herbicidas em barra lateral protegida com diferentes combinações de pontas de pulverização Herbicide spray deposition uniformity from a protected lateral spray boom with different spray tip combinations

Directory of Open Access Journals (Sweden)

A.C. Furlanetti

2001-12-01

Full Text Available O presente trabalho objetivou estudar a uniformidade de distribuição da calda de pulverização contendo herbicidas, em culturas perenes arbustivas, utilizando combinações de pontas de pulverização em barra lateral protegida, conduzida a pequena distância do alvo, na linha de culturas perenes arbustivas. Para isso, foi desenvolvido um programa computacional que permite simular a sobreposição do leque de pulverização, da porção protegida da barra e do leque formado pela ponta de pulverização do bico mais extremo da barra, de modo diferente dos demais programas. Após a seleção das melhores combinações de pontas de pulverização por meio de simulação dos padrões de deposição da pulverização das pontas individuais e dos coeficientes de variação menores que 10%, algumas dessas combinações foram testadas em campo, aplicando-se um herbicida sistêmico (glyphosate e outro com ação de contato (paraquat. Os resultados indicaram que o programa computacional desenvolvido pode constituir-se em um auxiliar valioso para a seleção das melhores combinações de pontas de pulverização. Em aplicações tanto do herbicida glyphosate quanto do paraquat, com volumes de calda mais reduzidos,abaixo de 100 L ha-1, destacaram-se como arranjos mais eficientes: a pontas TT110015 distanciadas de 52,5 cm entre si, combinadas com a ponta TK-0,5 na extremidade da barra a 50 cm do último bico, operando na velocidade de 5 km h-1 e pressão de 103 kPa (15 lbf pol-2, com distância de caminhamento do tronco da árvore de 20 cm ; b pontas SMCE2 distanciadas de 15 cm entre si, combinadas com a ponta TK-0,5 na extremidade da barra de 20 cm do último bico, operando na velocidade de 4 km h-1 e pressão de 414 kPa (60 lbf pol-2, com distância de caminhamento do tronco da árvore de 30 cm ; e c pontas TLX-2 distanciadas de 15 cm entre si, combinadas com a ponta TK-0,5 na extremidade da barra de 20 cm do último bico, operando à velocidade de 5 km

78 FR 71493 - Special Local Regulation; Lake Havasu City Christmas Boat Parade of Lights; Colorado River; Lake...

Science.gov (United States)

2013-11-29

...-AA00 Special Local Regulation; Lake Havasu City Christmas Boat Parade of Lights; Colorado River; Lake... temporarily modifying the dates for the special local regulation in support of the Lake Havasu City Christmas Boat Parade of Lights on the Colorado River. This modification is necessary to reflect the actual dates...

Mixed stock analysis of Lake Michigan's Lake Whitefish Coregonus clupeaformis commercial fishery

Science.gov (United States)

Andvik, Ryan; Sloss, Brian L.; VanDeHey, Justin A.; Claramunt, Randall M.; Hansen, Scott P.; Isermann, Daniel A.

2016-01-01

Lake whitefish (Coregonus clupeaformis) support the primary commercial fishery in Lake Michigan. Discrete genetic stocks of lake whitefish have been identified and tagging data suggest stocks are mixed throughout much of the year. Our objectives were to determine if (1) differential stock harvest occurs in the commercial catch, (2) spatial differences in genetic composition of harvested fish were present, and (3) seasonal differences were present in the harvest by commercial fisheries that operate in management zones WI-2 and WFM-01 (Green Bay, Lake Michigan). Mixed stock analysis was conducted on 17 commercial harvest samples (n = 78–145/sample) collected from various ports lake-wide during 2009–2010. Results showed significant mixing with variability in stock composition across most samples. Samples consisted of two to four genetic stocks each accounting for ≥ 10% the catch. In 10 of 17 samples, the stock contributing the largest proportion made up differences existed in the proportional stock contribution at a single capture location. Samples from Wisconsin's primary commercial fishing management zone (WI-2) were composed predominately of fish from the Big Bay de Noc (Michigan) stock as opposed to the geographically proximate, North–Moonlight Bay (Wisconsin) stock. These findings have implications for management and allocation of fish to various quotas. Specifically, geographic location of harvest, the current means of allocating harvest quotas, is not the best predictor of genetic stock harvest.

Generating High-Resolution Lake Bathymetry over Lake Mead using the ICESat-2 Airborne Simulator

Science.gov (United States)

Li, Y.; Gao, H.; Jasinski, M. F.; Zhang, S.; Stoll, J.

2017-12-01

Precise lake bathymetry (i.e., elevation/contour) mapping is essential for optimal decision making in water resources management. Although the advancement of remote sensing has made it possible to monitor global reservoirs from space, most of the existing studies focus on estimating the elevation, area, and storage of reservoirs—and not on estimating the bathymetry. This limitation is attributed to the low spatial resolution of satellite altimeters. With the significant enhancement of ICESat-2—the Ice, Cloud & Land Elevation Satellite #2, which is scheduled to launch in 2018—producing satellite-based bathymetry becomes feasible. Here we present a pilot study for deriving the bathymetry of Lake Mead by combining Landsat area estimations with airborne elevation data using the prototype of ICESat-2—the Multiple Altimeter Beam Experimental Lidar (MABEL). First, an ISODATA classifier was adopted to extract the lake area from Landsat images during the period from 1982 to 2017. Then the lake area classifications were paired with MABEL elevations to establish an Area-Elevation (AE) relationship, which in turn was applied to the classification contour map to obtain the bathymetry. Finally, the Lake Mead bathymetry image was embedded onto the Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM), to replace the existing constant values. Validation against sediment survey data indicates that the bathymetry derived from this study is reliable. This algorithm has the potential for generating global lake bathymetry when ICESat-2 data become available after next year's launch.

The limnology of L Lake: Results of the L-Lake monitoring program, 1986--1989

Energy Technology Data Exchange (ETDEWEB)

Bowers, J.A.

1991-12-15

L Lake was constructed in 1985 on the upper regions of Steel Creek, SRS to mitigate the heated effluents from L Reactor. In addition to the NPDES permit specifications (Outfall L-007) for the L-Reactor outfall, DOE-SR executed an agreement with the South Carolina Department of Health and Environmental Control (SCDHEC), that thermal effluents from L-Reactor will not substantially alter ecosystem components in the approximate lower half of L Lake. This region should be inhabited by Balanced (Indigenous) Biological Communities (BBCs) in accordance with Section 316(a) of the Pollution Control (Clean Water) Act (Public Law 92-500). In response to this requirement the Environmental Sciences Section/Ecology Group initiated a comprehensive biomonitoring program which documented the development of BBCs in L Lake from January 1986 through December 1989. This report summarizes the principal results of the program with regards to BBC compliance issues and community succession in L Lake. The results are divided into six sections: water quality, macronutrients, and phytoplankton, aquatic macrophytes, zooplankton, benthic macroinvertebrates, fish, and community succession. One of the prime goals of the program was to detect potential reactor impacts on L Lake.

Great Lakes Environmental Database (GLENDA)

Data.gov (United States)

U.S. Environmental Protection Agency — The Great Lakes Environmental Database (GLENDA) houses environmental data on a wide variety of constituents in water, biota, sediment, and air in the Great Lakes area.

Study of pollution in Rawal lake

International Nuclear Information System (INIS)

Ahmad, M.; Khan, M.I.A.; Nisar, M.; Kaleem, M.Y.

1999-01-01

It was intended to establish effects of pollution on quality of water of Rawal Lake, Islamabad. Six stations were located for collection of water. The data collected and analyzed so far indicated increasing pollution in the lake Increase in growth of hydrophytes in quite evident, leading towards process of eutrophication of the lake. (author)

Lake Morphometry for NHD Lakes in the Upper Portion of the Missouri Region 10 HUC

Data.gov (United States)

U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

Lake Morphometry for NHD Lakes in the Lower Portion of the Missouri Region 10 HUC

Data.gov (United States)

U.S. Environmental Protection Agency — Lake morphometry metrics are known to influence productivity in lakes and are important for building various types of ecological and environmental models of lentic...

Holocene evolution of the Tonle Sap Lake: valley network infill and rates of sedimentation in Cambodia's Great Lake

Science.gov (United States)

Best, J.; Darby, S. E.; Langdon, P. G.; Hackney, C. R.; Leyland, J.; Parsons, D. R.; Aalto, R. E.; Marti, M.

2017-12-01

Tonle Sap Lake, the largest freshwater lake in SE Asia (c. 120km long and 35 km wide), is a vital ecosystem that provides 40-60% of the protein for the population of Cambodia. The lake is fed by flow from the Mekong River that causes the lake rise in level by c. 8m during monsoonal and cyclone-related floods, with drainage of the lake following the monsoon. Hydropower dam construction on the Mekong River has raised concerns as to the fragility of the Tonle Sap habitat due to any changing water levels and sedimentation rates within the lake. This paper details results of sub-bottom profiling surveys of Tonle Sap Lake in October 2014 that detailed the stratigraphy of the lake and assessed rates of infill. An Innomar Parametric Echo Sounder (PES) was used to obtain c. 250 km of sub-bottom profiles, with penetration up to 15m below the lake bed at a vertical resolution of c. 0.20m. These PES profiles were linked to cores from the north of the lake and previous literature. The PES profiles reveal a network of valleys, likely LGM, with relief up to c. 15-20m, that have been infilled by a suite of Holocene sediments. The valley surface is picked out as a strong reflector throughout the lake, and displays a series of valleys that are up to c. 15m deep and commonly 50-200m wide, although some of the largest valleys are 1.2km in width. Modelling of channel network incision during LGM conditions generates landscapes consistent with our field observations. The Tonle Sap valley network is infilled by sediments that show firstly fluvial and/or subaerial slope sedimentation, and then by extensive, parallel-bedded, lacustrine sedimentation. Lastly, the top c. 1m of sedimentation is marked by a distinct basal erosional surface that can be traced over much of the Tonle Sap Lake, and that is overlain by a series of parallel PES reflections. This upper sediment layer is interpreted to represent sedimentation in the Tonle Sap lake due to sediment suspension settling but after a period

Isotopic fingerprints of anthropogenic molybdenum in lake sediments.

Science.gov (United States)

Chappaz, Anthony; Lyons, Timothy W; Gordon, Gwyneth W; Anbar, Ariel D

2012-10-16

We measured the molybdenum isotope compositions (δ(98)Mo) of well-dated sediment cores from two lakes in eastern Canada in an effort to distinguish between natural and anthropogenic contributions to these freshwater aquatic systems. Previously, Chappaz et al. (1) ascribed pronounced 20th-century Mo concentration enrichments in these lakes to anthropogenic inputs. δ(98)Mo values in the deeper sediments (reflecting predominantly natural Mo sources) differ dramatically between the two lakes: -0.32 ± 0.17‰ for oxic Lake Tantare and +0.64 ± 0.09‰ for anoxic Lake Vose. Sediment layers previously identified as enriched in anthropogenic Mo, however, reveal significant δ(98)Mo shifts of ± 0.3‰, resulting in isotopically heavier values of +0.05 ± 0.18‰ in Lake Tantare and lighter values of +0.31 ± 0.03‰ in Lake Vose. We argue that anthropogenic Mo modifies the isotopic composition of the recent sediments, and we determine δ(98)Mo(anthropogenic) values of 0.1 ± 0.1‰ (Lake Vose) and 0.2 ± 0.2‰ (Lake Tantare). These calculated inputs are consistent with the δ(98)Mo of molybdenite (MoS(2)) likely delivered to the lakes via smelting of porphyry copper deposits (Lake Vose) or through combustion of coal and oil also containing Mo (Lake Tantare). Our results confirm the utility of Mo isotopes as a promising fingerprint of human impacts and perhaps the specific sources of contamination. Importantly, the magnitudes of the anthropogenic inputs are large enough, relative to the natural Mo cycles in each lake, to have an impact on the microbiological communities.

Pacific salmonines in the Great Lakes Basin

Science.gov (United States)

Claramunt, Randall M.; Madenjian, Charles P.; Clapp, David; Taylor, William W.; Lynch, Abigail J.; Léonard, Nancy J.

2012-01-01

Pacific salmon (genus Oncorhynchus) are a valuable resource, both within their native range in the North Pacific rim and in the Great Lakes basin. Understanding their value from a biological and economic perspective in the Great Lakes, however, requires an understanding of changes in the ecosystem and of management actions that have been taken to promote system stability, integrity, and sustainable fisheries. Pacific salmonine introductions to the Great Lakes are comprised mainly of Chinook salmon, coho salmon, and steelhead and have accounted for 421, 177, and 247 million fish, respectively, stocked during 1966-2007. Stocking of Pacific salmonines has been effective in substantially reducing exotic prey fish abundances in several of the Great Lakes (e.g., lakes Michigan, Huron, and Ontario). The goal of our evaluation was to highlight differences in management strategies and perspectives across the basin, and to evaluate policies for Pacific salmonine management in the Great Lakes. Currently, a potential conflict exists between Pacific salmonine management and native fish rehabilitation goals because of the desire to sustain recreational fisheries and to develop self-sustaining populations of stocked Pacific salmonines in the Great Lakes. We provide evidence that suggests Pacific salmonines have not only become naturalized to the food webs of the Great Lakes, but that their populations (specifically Chinook salmon) may be fluctuating in concert with specific prey (i.e., alewives) whose populations are changing relative to environmental conditions and ecosystem disturbances. Remaining questions, however, are whether or not “natural” fluctuations in predator and prey provide enough “stability” in the Great Lakes food webs, and even more importantly, would a choice by managers to attempt to reduce the severity of predator-prey oscillations be antagonistic to native fish restoration efforts. We argue that, on each of the Great Lakes, managers are pursuing

L-Lake fish: L-Lake/Steel Creek Biological Monitoring Program, January 1986--December 1991

International Nuclear Information System (INIS)

Sayers, R.E. Jr.; Mealing, H.G. III

1992-04-01

The L Lake Biological Monitoring Program was designed to meet environmental regulatory requirements associated with the re-start of L-Reactor and address portions of Section 316(a) of the Clean Water Act, which requires an applicant for a discharge permit to provide scientific evidence that the discharge causes no significant impact on the indigenous ecosystem. The Department of Energy (DOE) must demonstrate that the discharge of L-Reactor effluent into L Lake will not inhibit the eventual establishment of a ''Balanced Biological Community'' (BBC) in at least 50% of the lake

Review of Reports on Lake Erie - Lake Ontario Waterway, New York. Appendix D. Economics.

Science.gov (United States)

1973-10-01

Venezuela (29 percent). Canada produced 48.3 million tons of iron ore in 1970 ,of which 23.9 million tons were exported to the United States (14.4 million...grain traffic, 1971 D-14 D-6 U.S. - Great Lakes grain exports 1960 - 1971 and projected D-15 D-7 U.S. doal traffic, Lake Erie - Lake Ontario, 1958-1970...Soybeans Wheat Barley Oats Rice Sorghum Grains Flaxseed Oilseeds, n.e.c. Tobacco, leaf Hay and Fodder Field crops, n.e.c. Fresh fruits Co ffee Cocoa beans

L-Lake fish: L-Lake/Steel Creek Biological Monitoring Program, January 1986--December 1991

Energy Technology Data Exchange (ETDEWEB)

Sayers, R.E. Jr.; Mealing, H.G. III [Normandeau Associates, Inc., New Ellenton, SC (United States)

1992-04-01

The L Lake Biological Monitoring Program was designed to meet environmental regulatory requirements associated with the re-start of L-Reactor and address portions of Section 316(a) of the Clean Water Act, which requires an applicant for a discharge permit to provide scientific evidence that the discharge causes no significant impact on the indigenous ecosystem. The Department of Energy (DOE) must demonstrate that the discharge of L-Reactor effluent into L Lake will not inhibit the eventual establishment of a ``Balanced Biological Community`` (BBC) in at least 50% of the lake.

The predominance of young carbon in Arctic whole-lake CH4 and CO2 emissions and implications for Boreal yedoma lakes.

Science.gov (United States)

Elder, C.; Xu, X.; Walker, J. C.; Walter Anthony, K. M.; Pohlman, J.; Arp, C. D.; Townsend-Small, A.; Hinkel, K. M.; Czimczik, C. I.

2017-12-01

Lakes in Arctic and Boreal regions are hotspots for atmospheric exchange of the greenhouse gases CO2 and CH4. Thermokarst lakes are a subset of these Northern lakes that may further accelerate climate warming by mobilizing ancient permafrost C (> 11,500 years old) that has been disconnected from the active C cycle for millennia. Northern lakes are thus potentially powerful agents of the permafrost C-climate feedback. While they are critical for projecting the magnitude and timing these feedbacks from the rapidly warming circumpolar region, we lack datasets capturing the diversity of northern lakes, especially regarding their CH4contributions to whole-lake C emissions and their ability to access and mobilize ancient C. We measured the radiocarbon (14C) ages of CH4 and CO2 emitted from 60 understudied lakes and ponds in Arctic and Boreal Alaska during winter and summer to estimate the ages of the C sources yielding these gases. Integrated mean ages for whole-lake emissions were inferred from the 14C-age of dissolved gases sampled beneath seasonal ice. Additionally, we measured concentrations and 14C values of gases emitted by ebullition and diffusion in summer to apportion C emission pathways. Using a multi-sourced mass balance approach, we found that whole-lake CH4 and CO2 emissions were predominantly sourced from relatively young C in most lakes. In Arctic lakes, CH4 originated from 850 14C-year old C on average, whereas dissolved CO2 was sourced from 400 14C-year old C, and represented 99% of total dissolved C flux. Although ancient C had a minimal influence (11% of total emissions), we discovered that lakes in finer-textured aeolian deposits (Yedoma) emitted twice as much ancient C as lakes in sandy regions. In Boreal, yedoma-type lakes, CH4 and CO2 were fueled by significantly older sources, and mass balance results estimated CH4-ebullition to comprise 50-60% of whole-lake CH4 emissions. The mean 14C-age of Boreal emissions was 6,000 14C-years for CH4-C, and 2

Inputting history of heavy metals into the inland lake recorded in sediment profiles: Poyang Lake in China

International Nuclear Information System (INIS)

Yuan Guoli; Liu Chen; Chen Long; Yang Zhongfang

2011-01-01

The temporal and spatial distribution of heavy metals (Cd, Hg, Pb, As and Cr) in Poyang Lake, the largest freshwater lake (3050 km 2 ) in China, were studied based on the sedimentary profiles. For this purpose, eight sedimentary cores were selected which located at lake area, outfall of lake and the main branch rivers, respectively. High-resolution profiles with interval 2 cm were used for analyzing the concentration of metals, and the ages of them were determined by 210 Pb and 137 Cs isotopic dating. While studying the change of metals concentration with the age in profile, it is found that the concentration of them in sediments was influenced not only by the sources in history but also by the sediment types. Based on this detailed work, the inventory and burden of heavy metals per decade were estimated in lake area during the past 50 years. Significantly, rivers-contribution ratio per decade was estimated to distinguish each river's contribution of heavy metals into lake while river-flux in history and metals concentration in profiles were considered as calculating factors. So, our research provides a proof to well understand the sedimentary history and the inputting history of heavy metals from main rivers into an inland lake.

Contrasting PCB bioaccumulation patterns among Lake Huron lake trout reflect basin-specific ecology.

Science.gov (United States)

Paterson, Gordon; Ryder, Mark; Drouillard, Ken G; Haffner, G Douglas

2016-01-01

This study collected multiple age classes of lake trout from Lake Huron's Main Basin, Georgian Bay, and North Channel regions to compare and contrast top predator polychlorinated biphenyl (PCB) bioaccumulation patterns in separate compartments of the same ecosystem. Sum PCB concentrations were highest for Main Basin (260 ± 24.9 ng g(-1) wet wt) fish, followed by Georgian Bay (74.6 ± 16.2 ng g(-1) ) and North Channel (42.0 ± 3.3 ng g(-1)) fish. Discriminant functions analysis of lake trout PCB profiles and stable carbon (δ(13)C) and nitrogen (δ(15)N) isotope values clearly distinguished fish by location, indicating high degrees of basin fidelity throughout their lifetimes in addition to highly contrasting PCB bioaccumulation profiles. These unique profiles were not attributable to significant differences in lake trout lipid contents (p = 0.856) or trophic position (δ(15)N; p = 0.334), with rainbow smelt representing the primary prey across the basins. Furthermore, significant differences were observed among the basins for the relationships between PCB biomagnification factors and hydrophobicity. An empirical model for predicting PCB biomagnification in Lake Huron lake trout indicated that basin-specific population growth rates and prey abundances were significant for explaining these contrasting patterns of PCB bioaccumulation. The results of the present study are fundamental for understanding the role of ecology in legacy persistent organic pollutant (POP) bioaccumulation. Specifically, ecosystem characteristics such as prey abundances, foraging ecology, and ultimately consumer growth can regulate the variability of legacy POP bioaccumulation as observed within and among a wide range of freshwater ecosystems. © 2015 SETAC.

Regionalisation for lake level simulation – the case of Lake Tana in the Upper Blue Nile, Ethiopia

Directory of Open Access Journals (Sweden)

T. H. M. Rientjes

2011-04-01

Full Text Available In this study lake levels of Lake Tana are simulated at daily time step by solving the water balance for all inflow and outflow processes. Since nearly 62% of the Lake Tana basin area is ungauged a regionalisation procedure is applied to estimate lake inflows from ungauged catchments. The procedure combines automated multi-objective calibration of a simple conceptual model and multiple regression analyses to establish relations between model parameters and catchment characteristics.

A relatively small number of studies are presented on Lake Tana's water balance. In most studies the water balance is solved at monthly time step and the water balance is simply closed by runoff contributions from ungauged catchments. Studies partly relied on simple ad-hoc procedures of area comparison to estimate runoff from ungauged catchments. In this study a regional model is developed that relies on principles of similarity of catchments characteristics. For runoff modelling the HBV-96 model is selected while multi-objective model calibration is by a Monte Carlo procedure. We aim to assess the closure term of Lake Tana's water balance, to assess model parameter uncertainty and to evaluate effectiveness of a multi-objective model calibration approach to make hydrological modeling results more plausible.

For the gauged catchments, model performance is assessed by the Nash-Sutcliffe coefficient and Relative Volumetric Error and resulted in satisfactory to good performance for six, large catchments. The regional model is validated and indicated satisfactory to good performance in most cases. Results show that runoff from ungauged catchments is as large as 527 mm per year for the simulation period and amounts to approximately 30% of Lake Tana stream inflow. Results of daily lake level simulation over the simulation period 1994–2003 show a water balance closure term of 85 mm per year that accounts to 2.7% of the total lake inflow. Lake level

Quantifying the impact of bathymetric changes on the hydrological regimes in a large floodplain lake: Poyang Lake

Science.gov (United States)

Yao, Jing; Zhang, Qi; Ye, Xuchun; Zhang, Dan; Bai, Peng

2018-06-01

The hydrological regime of a lake is largely dependent on its bathymetry. A dramatic water level reduction has occurred in Poyang Lake in recent years, coinciding with significant bed erosion. Few studies have focused on the influence of bathymetric changes on the hydrological regime in such a complex river-lake floodplain system. This study combined hydrological data and a physically based hydrodynamic model to quantify the influence of the bathymetric changes (1998-2010) on the water level spatiotemporal distribution in Poyang Lake, based on a dry year (2006), a wet year (2010) and an average year (2000-2010). The following conclusions can be drawn from the results of this study: (1) The bed erosion of the northern outlet channel averaged 3 m, resulting in a decrease in the water level by 1.2-2 m in the northern channels (the most significantly influenced areas) and approximately 0.3 m in the central lake areas during low-level periods. The water levels below 16 m and 14 m were significantly affected during the rising period and recession period, respectively. The water level reduction was enhanced due to lower water levels. (2) The water surface profiles adjusted, and the rising and recession rates of the water level increased by 0.5-3.1 cm/d at the lake outlet. The bathymetric influence extended across the entire lake due to the emptying effect, resulting in a change in the water level distribution. The average annual outflow increased by 6.8%. (3) The bathymetric changes contributed approximately 14.4% to the extreme low water level in autumn 2006 and enhanced the drought in the dry season. This study quantified the impact of the bathymetric changes on the lake water levels, thereby providing a better understanding of the potential effects of continued sand mining operations and providing scientific explanations for the considerable variations in the hydrological regimes of Poyang Lake. Moreover, this study attempts to provide a reference for the assessment of

Predicting the locations of naturally fishless lakes

Science.gov (United States)

Schilling, Emily Gaenzle; Loftin, C.S.; Degoosh, K.E.; Huryn, Alexander D.; Webster, K.E.

2008-01-01

1. Fish have been introduced into many previously fishless lakes throughout North America over the past 100+ years. It is difficult to determine the historical distribution of fishless lakes, however, because these introductions have not always been well-documented. 2. Due to its glacial history and low human population density, the state of Maine (U.S.A.) may host the greatest number of naturally fishless lakes in the northeastern United States. However, less than one-quarter of Maine's 6000+ lakes have been surveyed for fish presence, and no accurate assessments of either the historical or current abundance and distribution of fishless lakes exist. 3. We developed methods to assess the abundance and distribution of Maine's naturally fishless lakes (0.6-10.1 ha). We hypothesized that the historical distribution of fishless lakes across a landscape is controlled by geomorphic and geographic conditions. 4. We used ArcGIS to identify landscape-scale geomorphic and geographic factors (e.g. connectivity, surrounding slope) correlated with fish absence in two geomorphic regions of Maine - the western and interior mountains and the eastern lowlands and foothills. By using readily available geographic information systems data our method was not limited to field-visited sites. We estimated the likelihood that a particular lake is fishless with a stepwise logistic regression model developed for each region. 5. The absence of fish from western lakes is related to altitude (+), minimum percent slope in the 500 m buffer (+), maximum percent slope in the 500 m buffer (+) and percent cover of herbaceous-emergent wetland in 1000 m buffer (-). The absence of fish from eastern lakes is related to the lack of a stream within 50 m of the lake. 6. The models predict that a total of 4% (131) of study lakes in the two regions were historically fishless, with the eastern region hosting a greater proportion than the western region. 7. We verified the model predictions with two

Decline of the world's saline lakes

Science.gov (United States)

Wayne A. Wurtsbaugh; Craig Miller; Sarah E. Null; R. Justin DeRose; Peter Wilcock; Maura Hahnenberger; Frank Howe; Johnnie Moore

2017-01-01

Many of the world’s saline lakes are shrinking at alarming rates, reducing waterbird habitat and economic benefits while threatening human health. Saline lakes are long-term basin-wide integrators of climatic conditions that shrink and grow with natural climatic variation. In contrast, water withdrawals for human use exert a sustained reduction in lake inflows and...

Status and future of Lake Huron fish communities

Science.gov (United States)

Ebener, M.P.; Johnson, J.E.; Reid, D.M.; Payne, N.P.; Argyle, R.L.; Wright, G.M.; Krueger, K.; Baker, J.P.; Morse, T.; Weise, J.; Munawar, M.; Edsall, T.; Leach, J.

1995-01-01

In 1993, fishery management agencies with jurisdiction over Lake Huron fish populations developed draft fish community objectives in response to the Joint Strategic Plan for Management of Great Lakes Fisheries. The Joint Strategic Plan charged the Great Lakes Fishery Commission sponsored Lake Huron Committee to define objectives for what the fish community of Lake Huron should look like in the future, and to develop means for measuring progress toward the objectives. The overall management objective for Lake Huron is to 'over the next two decades restore an ecologically balanced fish community dominated by top predators and consisting largely of self-sustaining, indigenous and naturalized species and capable of sustaining annual harvests of 8.9 million kg'. This paper represents the first attempt at consolidating current biological information from different management agencies on a lake-wide basis for the purpose of assessing the current status and dynamics of Lake Huron fishes.

Exploration of microbial diversity and community structure of Lonar Lake: the only hypersaline meteorite crater lake within basalt rock

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Dhiraj ePaul

2016-01-01

Full Text Available Lonar Lake is a hypersaline and hyperalkaline soda lake and the only meteorite impact crater in the world created in the basalt rocks. Although culture-dependent studies have been reported, the comprehensive understanding of microbial community composition and structure of Lonar Lake remain obscure. In the present study, microbial community structure associated with Lonar Lake sediment and water samples was investigated using high throughput sequencing. Microbial diversity analysis revealed the existence of diverse, yet near consistent community composition. The predominance of bacterial phyla Proteobacteria (30% followed by Actinobacteria (24%, Firmicutes (11% and Cyanobacteria (5% was observed. Bacterial phylum Bacteroidetes (1.12%, BD1-5 (0.5%, Nitrospirae (0.41% and Verrucomicrobia (0.28% were detected as relatively minor populations in Lonar Lake ecosystem. Within Proteobacteria, Gammaproteobacteria represented the most abundant population (21-47% among all the sediments and as a minor population in water samples. Bacterial members Proteobacteria and Firmicutes were present significantly higher (p≥0.05 in sediment samples, whereas members of Actinobacteria, Candidate_division_TM7 and Cyanobacteria (p≥0.05 were significantly abundant in water samples. It was noted that compared to other hypersaline soda lakes, Lonar Lake samples formed one distinct cluster, suggesting a different microbial community composition and structure. The present study reports for the first time the different composition of indigenous microbial communities between the sediment and water samples of Lonar Lake. Having better insight of community structure of this Lake ecosystem could be useful in understanding the microbial role in the geochemical cycle for future functional exploration of the unique hypersaline Lonar Lake.

Depth gradients in food-web processes linking habitats in large lakes: Lake Superior as an exemplar ecosystem

Science.gov (United States)

Sierszen, Michael E.; Hrabik, Thomas R.; Stockwell, Jason D.; Cotter, Anne M; Hoffman, Joel C.; Yule, Daniel L.

2014-01-01

In large lakes around the world, depth-based changes in the abundance and distribution of invertebrate and fish species suggest that there may be concomitant changes in patterns of resource allocation. Using Lake Superior of the Laurentian Great Lakes as an example, we explored this idea through stable isotope analyses of 13 major fish taxa.

Olvido dirigido de falsas memorias: ¿Podemos olvidar intencionalmente una falsa memoria?

OpenAIRE

Pitarque, Alfonso; Algarabel González, Salvador; Dasí Vivó, Carmen; Ruiz, Juan Carlos

2003-01-01

Directed forgetting of false memories: Can we forget a false memory? In two directed forgetting experiments subjects were required to forget some false memories. In experiment 1 the 13 words from list 1 were related to a non presented critical word whereas the 13 words from list 2 were unrelated. In experiment 2 both list 1 and 2 had 18 words: 6 words related to a first critical word, 6 related to a second critical word, and the last 6 words to a third critical word. None of both experiments ...

Diatoms in Liyu Lake, Eastern Taiwan

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Liang-Chi Wang

2010-09-01

Full Text Available This study described the diatoms appeared in the sediments of Liyu Lake, a lowland natural lake situated at Hualen, eastern Taiwan. A total of 50 species was found in the sediments of this eutrophic lake. In them, 8 species were reported for the first time in Taiwan. They are: Cymbella thienemannii, Navicula absoluta, Navicula bacillum, Frustulia rhomboides var. crassinervia, Gyrosigma procerum, Nitzschia paleacea Epithemia smithii and Eunotia subarcuatioides. The ultrastructures of each species were described on the basis of observations under a scanning electron microscope. The ecological implications of the occurrence of these diatom species in this lake were inferred.

Lake Titicaca: History and current studies

International Nuclear Information System (INIS)

Paredes Riveros, M.A.; Gonfiantini, R.

1999-01-01

This article summarizes results of Titicaca lake water balance studies including the findings of the IAEA Technical Cooperation Project RLA/08/022. Direct precipitation over the lake accounts for about 55% of the water inflow and rivers and streams provide about 45% of the water inflow. Diffuse groundwater leakage into the lake from coastal aquifers is believed to represent a negligible term of water balance. Evaporation from the lake is strong and accounts for more than 95% of the water losses. The isotopic and chemical composition data obtained within the frameworks of the IAEA Technical Cooperation Project RLA/08/022 are discussed

Lake Titicaca: History and current studies

Energy Technology Data Exchange (ETDEWEB)

Paredes Riveros, M A [PELT, Puno (Peru); Gonfiantini, R [Istituto di Geocronologia e Geochimica Isotopica del CNR, Pisa (Italy)

1999-12-01

This article summarizes results of Titicaca lake water balance studies including the findings of the IAEA Technical Cooperation Project RLA/08/022. Direct precipitation over the lake accounts for about 55% of the water inflow and rivers and streams provide about 45% of the water inflow. Diffuse groundwater leakage into the lake from coastal aquifers is believed to represent a negligible term of water balance. Evaporation from the lake is strong and accounts for more than 95% of the water losses. The isotopic and chemical composition data obtained within the frameworks of the IAEA Technical Cooperation Project RLA/08/022 are discussed.

The origin of shallow lakes in the Khorezm Province, Uzbekistan, and the history of pesticide use around these lakes

Science.gov (United States)

Rosen, Michael R.; Crootof, Arica; Reidy, Liam; Saito, Laurel; Nishonov, Bakhriddin; Scott, Julian A.

2018-01-01

The economy of the Khorezm Province in Uzbekistan relies on the large-scale agricultural production of cotton. To sustain their staple crop, water from the Amu Darya is diverted for irrigation through canal systems constructed during the early to mid-twentieth century when this region was part of the Soviet Union. These diversions severely reduce river flow to the Aral Sea. The Province has >400 small shallow (data indicate that the majority of the lakes investigated are less than 150 years old, which supports a recent origin of the lakes. The thickness of lacustrine sediments in the cores analyzed ranged from 20 to 60 cm in all but two of the lakes, indicating a relatively slow sedimentation rate and a relatively short-term history for the lakes. Hydrologic changes in the lakes are evident from loss on ignition and pollen analyses of a subset of the lake cores. The data indicate that the lakes have transitioned from a dry, saline, arid landscape during pre-lake conditions (low organic carbon content) and low pollen concentrations (in the basal sediments) to the current freshwater lakes (high organic content), with abundant freshwater pollen taxa over the last 50–70 years. Sediments at the base of the cores contain pollen taxa dominated by Chenopodiaceae and Tamarix, indicating that the vegetation growing nearby was tolerant to arid saline conditions. The near surface sediments of the cores are dominated by Typha/Sparganium, which indicate freshwater conditions. Increases in pollen of weeds and crop plants indicate an intensification of agricultural activities since the 1950s in the watersheds of the lakes analyzed. Pesticide profiles of DDT (dichlorodiphenyltrichloroethane) and its degradates and γ-HCH (gamma-hexachlorocyclohexane), which were used during the Soviet era, show peak concentrations in the top 10 cm of some of the cores, where estimated ages of the sediments (1950–1990) are associated with peak pesticide use during the Soviet era. These data

Methods of evaluating ore processing and effluent treatment for Cigar Lake ore at the Rabbit Lake Mill

International Nuclear Information System (INIS)

Edwards, C.R.

2002-01-01

Cigar Lake is the second-largest, high grade uranium orebody in the world. Mineable reserves for Cigar Lake Phase 1 are estimated at 191 million pounds U 3 O 8 with a grade of 25.6% U 3 O 8 . Subject to regulatory approval, Cameco intends to process the majority of ore from Cigar Lake in the Rabbit Lake mill. Cameco initiated a programme to study the processing of Cigar Lake ore and the treatment of the resulting waste streams. Laboratory and follow-up pilot scale ore leaching tests with Cigar Lake ore samples were performed. Tailings and effluents were generated from the products of the pilot scale leach tests. Mill process tailings were blended with ground waste rock. Using these materials, geotechnical and geochemical properties, including long term tailings pore water characteristics, will be evaluated. In addition, proposed changes to the mill waste treatment operations were developed to deal with increased levels of arsenic and radium in the waste streams. This paper describes the methods and techniques Cameco used in this programme. (author)

Restoration of Eutrophic Lakes with Fluctuating Water Levels: A 20-Year Monitoring Study of Two Inter-Connected Lakes

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Meryem Beklioğlu

2017-02-01

Full Text Available Eutrophication continues to be the most important problem preventing a favorable environmental state and detrimentally impacting the ecosystem services of lakes. The current study describes the results of analyses of 20 year monitoring data from two interconnected Anatolian lakes, Lakes Mogan and Eymir, receiving sewage effluents and undergoing restoration. The first step of restoration in both lakes was sewage effluent diversion. Additionally, in hypertrophic Lake Eymir, biomanipulation was conducted, involving removal of benthi-planktivorous fish and prohibition of pike fishing. The monitoring period included high (H and low (L water levels (WL enabling elucidation of the effects of hydrological changes on lake restoration. In shallower Lake Mogan, macrophyte abundance increased after the sewage effluent diversion in periods with low water levels even at turbid water. In comparatively deeper Lake Eymir, the first biomanipulation led to a clear water state with abundant macrophyte coverage. However, shortly after biomanipulation, the water clarity declined, coinciding with low water level (LWL periods during which nutrient concentrations increased. A second biomanipulation was conducted, mostly during high water level (HWL period, resulting in a major decrease in nutrient concentrations and clearer water, but without an expansion of macrophytes. We conclude that repetitive fish removal may induce recovery but its success may be confounded by high availability of nutrients and adverse hydrological conditions.

Simulation of hydrodynamics, water quality, and lake sturgeon habitat volumes in Lake St. Croix, Wisconsin and Minnesota, 2013

Science.gov (United States)

Smith, Erik A.; Kiesling, Richard L.; Ziegeweid, Jeffrey R.; Elliott, Sarah M.; Magdalene, Suzanne

2018-01-05

Lake St. Croix is a naturally impounded, riverine lake that makes up the last 40 kilometers of the St. Croix River. Substantial land-use changes during the past 150 years, including increased agriculture and urban development, have reduced Lake St. Croix water-quality and increased nutrient loads delivered to Lake St. Croix. A recent (2012–13) total maximum daily load phosphorus-reduction plan set the goal to reduce total phosphorus loads to Lake St. Croix by 20 percent by 2020 and reduce Lake St. Croix algal bloom frequencies. The U.S. Geological Survey, in cooperation with the National Park Service, developed a two-dimensional, carbon-based, laterally averaged, hydrodynamic and water-quality model, CE–QUAL–W2, that addresses the interaction between nutrient cycling, primary production, and trophic dynamics to predict responses in the distribution of water temperature, oxygen, and chlorophyll a. Distribution is evaluated in the context of habitat for lake sturgeon, including a combination of temperature and dissolved oxygen conditions termed oxy-thermal habitat.The Lake St. Croix CE–QUAL–W2 model successfully reproduced temperature and dissolved oxygen in the lake longitudinally (from upstream to downstream), vertically, and temporally over the seasons. The simulated water temperature profiles closely matched the measured water temperature profiles throughout the year, including the prediction of thermocline transition depths (often within 1 meter), the absolute temperature of the thermocline transitions (often within 1.0 degree Celsius), and profiles without a strong thermocline transition. Simulated dissolved oxygen profiles matched the trajectories of the measured dissolved oxygen concentrations at multiple depths over time, and the simulated concentrations matched the depth and slope of the measured concentrations.Additionally, trends in the measured water-quality data were captured by the model simulation, gaining some potential insights into the

What caused the decline of China's largest freshwater lake? Attribution analysis on Poyang Lake water level variations in recent years

Science.gov (United States)

Ye, Xuchun; Xu, Chong-Yu; Zhang, Qi

2017-04-01

In recent years, dramatic decline of water level of the Poyang Lake, China's largest freshwater lake, has raised wide concerns about the water security and wetland ecosystem. This remarkable hydrological change coincided with several factors like the initial operation of the Three Gorges Dam (TGD) in 2003, the big change of lake bottom topography due to extensive sand mining in the lake since 2000, and also climate change and other human activities in the Yangtze River basin may add to this complexity. Questions raised to what extent that the lake hydrological changes is caused by climate change and/or human activities. In this study, quantitative assessment was conducted to clarify the magnitude and mechanism of specific influencing factors on recent lake decline (2003-2014), with reference to the period of 1980-1999. The attempts were achieved through the reconstruction of lake water level scenarios by the framework of neural network. Major result indicates that the effect of lake bottom topography change due to sand mining activities has became the dominant factor for the recent lake decline, especially in winter season with low water level. However, the effect of TGD regulation shows strong seasonal features, its effect can accounts for 33%-42% of the average water level decline across the lake during the impoundment period of September-October. In addition, the effect of climate change and other human activities over the Yangtze River basin needs to be highly addressed, which is particularly prominent on reducing lake water level during the summer flood season and autumn recession period. The result also revealed that due to different mechanism, the responses of the lake water level to the three influencing factors are not consistent and show great spatial and temporal differences.

Fluctuations of Lake Orta water levels: preliminary analyses

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Helmi Saidi

2016-04-01

Full Text Available While the effects of past industrial pollution on the chemistry and biology of Lake Orta have been well documented, annual and seasonal fluctuations of lake levels have not yet been studied. Considering their potential impacts on both the ecosystem and on human safety, fluctuations in lake levels are an important aspect of limnological research. In the enormous catchment of Lake Maggiore, there are many rivers and lakes, and the amount of annual precipitation is both high and concentrated in spring and autumn. This has produced major flood events, most recently in November 2014. Flood events are also frequent on Lake Orta, occurring roughly triennially since 1917. The 1926, 1951, 1976 and 2014 floods were severe, with lake levels raised from 2.30 m to 3.46 m above the hydrometric zero. The most important event occurred in 1976, with a maximum level equal to 292.31 m asl and a return period of 147 years. In 2014 the lake level reached 291.89 m asl and its return period was 54 years. In this study, we defined trends and temporal fluctuations in Lake Orta water levels from 1917 to 2014, focusing on extremes. We report both annual maximum and seasonal variations of the lake water levels over this period. Both Mann-Kendall trend tests and simple linear regression were utilized to detect monotonic trends in annual and seasonal extremes, and logistic regression was used to detect trends in the number of flood events. Lake level decreased during winter and summer seasons, and a small but statistically non-significant positive trend was found in the number of flood events over the period. We provide estimations of return period for lake levels, a metric which could be used in planning lake flood protection measures.

Microbial ecology of soda lakes: investigating sulfur and nitrogen cycling at Mono Lake, CA, USA

Science.gov (United States)

Fairbanks, D.; Phillips, A. A.; Wells, M.; Bao, R.; Fullerton, K. M.; Stamps, B. W.; Speth, D. R.; Johnson, H.; Sessions, A. L.

2017-12-01

Soda lakes represent unique ecosystems characterized by extremes of pH, salinity and distinct geochemical cycling. Despite these extreme conditions, soda lakes are important repositories of biological adaptation and have a highly functional microbial system. We investigated the biogeochemical cycling of sulfur and nitrogen compounds in Mono Lake, California, located east of the Sierra Nevada mountains. Mono lake is characterized by hyperalkaline, hypersaline and high sulfate concentrations and can enter prolonged periods of meromixis due to freshwater inflow. Typically, the microbial sulfur cycle is highly active in soda lakes with both oxidation and reduction of sulfur compounds. However, the biological sulfur cycle is connected to many other main elemental cycles such as carbon, nitrogen and metals. Here we investigated the interaction between sulfur and nitrogen cycling in Mono lake using a combination of molecular, isotopic, and geochemical observations to explore the links between microbial phylogenetic composition and functionality. Metagenomic and 16S rRNA gene amplicon sequencing were determined at two locations and five depths in May 2017. 16S rRNA gene amplicon sequencing analysis revealed organisms capable of both sulfur and nitrogen cycling. The relative abundance and distribution of functional genes (dsrA, soxAB, nifH, etc) were also determined. These genetic markers indicate the potential in situ relevance of specific carbon, nitrogen, and sulfur pathways in the water column prior to the transition to meromictic stratification. However, genes for sulfide oxidation, denitrification, and ammonification were present. Genome binning guided by the most abundant dsrA sequences, GC content, and abundance with depth identified a Thioalkalivibrio paradoxus bin containing genes capable of sulfur oxidation, denitrification, and nitrate reduction. The presence of a large number of sulfur and nitrogen cycling genes associated with Thioalkalivibrio paradoxus

Influence of precipitation, landscape and hydrogeomorphic lake features on pelagic allochthonous indicators in two connected ultraoligotrophic lakes of North Patagonia

International Nuclear Information System (INIS)

Queimaliños, Claudia; Reissig, Mariana; Diéguez, María del Carmen; Arcagni, Marina; Ribeiro Guevara, Sergio; Campbell, Linda; Soto Cárdenas, Carolina; Rapacioli, Raúl

2012-01-01

We investigated the terrestrial influence on two chained deep ultraoligotrophic lakes of North Patagonia (Argentina) through the seasonal analysis of two pelagic allochthonous indicators: i) water color, as a proxy of allochthonous dissolved organic matter in lakes; and ii) the color to chlorophyll a ratio (Color:Chla), as an indicator of the relationship between allochthonous and autochthonous carbon pools. We also evaluated the potential transfer pathways of the allochthonous dissolved organic matter into the pelagic food webs of these deep lakes, including the natural zooplankton δ 13 C in the analysis. The dynamics of the allochthonous indicators were related to the precipitation regime, water level fluctuations, and hydrogeomorphic and catchment features of lakes Moreno East and Moreno West. The water color (absorbance at 440 nm) was extremely low ( −1 ) in both lakes regardless of the season. However, precipitation and snowmelt regimes drove the increase and decrease of water color, respectively. A significant positive relationship between the zooplankton bulk δ 13 C with the water color would suggest an input of allochthonous organic carbon into the pelagic consumers. The incorporation of the dissolved allochthonous material into higher trophic levels is likely favored by the bacterivorous behavior of planktonic organisms, mixotrophic flagellates and ciliates, which dominate the pelagic food webs of these Patagonian lakes. Morphometric aspects, mainly the higher water residence time, led to lower values of allochthony in Moreno East compared to Moreno West, probably accentuated by its upper position in the lake chain. Overall, our results suggest that these allochthonous signals can bring insight into the magnitude of the interaction between terrestrial environments and lake ecosystems, even in extremely clear and ultraoligotrophic systems, such as the Andean Patagonian lakes. - Highlights: ► Pelagic allochthonous indicators were detected in two

Exposure-related effects of Zequanox on juvenile lake sturgeon (Acipenser fulvescens) and lake trout (Salvelinus namaycush)

Science.gov (United States)

Luoma, James A.; Severson, Todd J.; Wise, Jeremy K.; Barbour, Matthew

2018-01-01

The environmental fate, persistence, and non-target animal impacts of traditional molluscicides for zebra, Dreissena polymorpha, and quagga, D. bugensis, mussel control led to the development of the biomolluscicide Zequanox. Although previous research has demonstrated the specificity of Zequanox, one study indicated sensitivity of salmonids and lake sturgeon, Acipenser fulvescens, following non-label compliant exposures to Zequanox. This study was conducted to evaluate sublethal and lethal impacts of Zequanox exposure on juvenile lake sturgeon and lake trout, Salvelinus namaycush, following applications that were conducted in a manner consistent with the Zequanox product label. Fish were exposed to 50 or 100 mg/L of Zequanox as active ingredient for 8 h and then held for 33 d to evaluate latent impacts. No acute mortality was observed in either species; however, significant latent mortality (P < 0.01, df = 9; 46.2%) was observed in lake trout that were exposed to the highest dose of Zequanox. Statistically significant (P < 0.03, df = 9), but biologically minimal differences were observed in the weight (range 20.17 to 21.49 g) of surviving lake sturgeon at the termination of the 33 d post-exposure observation period. Statistically significant (P < 0.05, df = 9) and biologically considerable differences were observed in the weight (range 6.19 to 9.55 g) of surviving lake trout at the termination of the 33 d post-exposure observation period. Histologic evaluation of lake trout gastrointestinal tracts suggests that the mode of action in lake trout is different from the mode of action that induces zebra and quagga mussel mortality. Further research could determine the sensitivity of other salmonid species to Zequanox and determine if native fish will avoid Zequanox treated water.

Thin, Conductive Permafrost Surrounding Lake Fryxell Indicates Salts From Past Lakes, McMurdo Dry Valleys, Antarctica

Science.gov (United States)

Foley, N.; Tulaczyk, S. M.; Gooseff, M. N.; Myers, K. F.; Doran, P. T.; Auken, E.; Dugan, H. A.; Mikucki, J.; Virginia, R. A.

2017-12-01

In the McMurdo Dry Valleys (MDV), permafrost should be thick and liquid water rare. However, despite the well below zero mean annual temperature in this cryospheric desert, liquid water can be found in lakes, summer melt streams, subglacial outflow, and - recent work has shown - underneath anomalously thin permafrost. In part, this niche hydrosphere is maintained by the presence of salts, which depress the freezing point of water to perhaps as cold as -10° Celsius. We detected widespread salty water across the MDV in lakes and at depth using a helicopter-borne Time Domain Electromagnetic (TDEM) sensor. By using the presence of brines to mark the transition from frozen permafrost (near the surface) to unfrozen ground (at depth), we have created a map of permafrost thickness in Lower Taylor Valley (LTV), a large MDV with a complex history of glaciation and occupation by lakes. Our results show that permafrost is thinner ( 200m) than would be expected based on geothermal gradient measurements (up to 1000m), a result of the freezing point depression caused by salt and potentially enhanced by an unfinished transient freezing process. Near Lake Fryxell, a large, brackish lake in the center of LTV, permafrost is very thin (about 30-40m) and notably more electrically conductive than more distal permafrost. This thin ring of conductive permafrost surrounding the lake basin most likely reflects the high presence of salts in the subsurface, preventing complete freezing. These salts may be a remnant of the salty bottom waters of a historic larger lake (LGM glacially dammed Lake Washburn) or the remnant of salty basal water from a past advance of Taylor Glacier, which now sits many km up-valley but is known to contain brines which currently flow onto the surface and directly into the subsurface aquifer.

Life history of lake herring of Green Bay, Lake Michigan

Science.gov (United States)

Smith, Stanford H.

1956-01-01

Although the lake herring has been an important contributor to the commercial fish production of Green Bay, little has been known about it. This study is based on field observations and data from about 6,500 lake herring collected over the period 1948 to 1952. Relatively nonselective commercial pound nets were a primary source of material for the study of age and growth. Commercial and experimental gill nets were used to obtain data on gear selectivity and vertical distribution. Scales were employed to investigate age and growth. Age group IV normally dominated commercial catches during the first half of the calendar year and age group III the last half. At these ages the fish averaged about 10.5 inches in length. The season's growth started in May, was most rapid in July, and terminated near the end of October. The sexes grew at the same rate. Selectivity of fishing gear was found to influence the estimation of growth. Geographical and annual differences in growth are shown. Factors that might contribute to discrepancies in calculated growth are evaluated. Possible real and apparent causes of growth compensation are given. The relation between length and weight is shown to vary with sex, season, year, and method of capture. Females were relatively more plentiful in commercial catches in February than in May through December. The percentage of females decreased with increase in age in pound-net catches but increased with age in gill-net samples. Within a year class the percentage of females decreased with increase in age. Most Green Bay lake herring mature during their second or third year of life. They are pelagic spawners with most intensive spawning over shallow areas. Spawning takes place between mid-November and mid-December, and eggs hatch in April and May. Lake herring ovaries contained from 3,500 to 11,200 eggs (averaged 6,375). Progress of spawning by age, sex, and length is given. Lake herring were distributed at all depths in Green Bay in early May, were

A post-Calumet shoreline along southern Lake Michigan

Science.gov (United States)

Capps, D.K.; Thompson, T.A.; Booth, R.K.

2007-01-01

The southern shore of Lake Michigan is the type area for many of ancestral Lake Michigan's late Pleistocene lake phases, but coastal deposits and features of the Algonquin phase of northern Lake Michigan, Lake Huron, and Lake Superior are not recognized in the area. Isostatic rebound models suggest that Algonquin phase deposits should be 100 m or more below modern lake level. A relict shoreline, however, exists along the lakeward margin of the Calumet Beach that was erosional west of Deep River and depositional east of the river. For this post-Calumet shoreline, the elevation of basal foreshore deposits east of Deep River and the base of the scarp west of Deep River indicate a slightly westward dipping water plane that is centered at ???184 m above mean sea level. Basal foreshore elevations also indicate that lake level fell ???2 m during the development of the shoreline. The pooled mean of radiocarbon dates from the surface of the peat below post-Calumet shoreline foreshore deposits indicate that the lake transgressed over the peat at 10,560 ?? 70 years B.P. Pollen assemblages from the peat are consistent with this age. The elevation and age of the post-Calumet shoreline are similar to the Main Algonquin phase of Lake Huron. Recent isostatic rebound models do not adequately address a high-elevation Algonquin-age shoreline along the southern shore of Lake Michigan, but the Goldthwait (1908) hinge-line model does. ?? 2006 Springer Science+Business Media B.V.