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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Surface and small-scale processes of biogeochemical cycling of organic matter in tidal sediments /

Shaughnessy, Gwendolyn A. January 2007 (has links) (PDF)
Thesis (M.S.)--University of North Carolina Wilmington, 2007. / Includes bibliographical references (Leaves: 62-68)
32

Nitrogen and phosphorus availability, ecosystem processes and plant community dynamics in boreal wetland meadows /

Erickson, Heather E. January 1994 (has links)
Thesis (Ph. D.)--University of Washington, 1994. / Vita. Includes bibliographical references (leaves [110]-119).
33

Enrichment of ¹⁵N and ¹⁸O in stratospheric nitrous oxide : observations, experimental results, and implications /

Rahn, Thomas A., January 1998 (has links)
Thesis (Ph. D.)--University of California, San Diego, 1998. / Vita. Includes bibliographical references.
34

Temporal variability of iron speciation in rainwater and its impact on the biogeochemical cycling of iron in seawater

Yavari, Josephine R. January 2009 (has links) (PDF)
Thesis (M.S.)--University of North Carolina Wilmington, 2009. / Title from PDF title page (January 15, 2010) Includes bibliographical references (81-83)
35

The role of vegetation and soil in the biogeochemical cycling of mercury

Stamenkovic, Jelena. January 2008 (has links)
Thesis (Ph. D.)--University of Nevada, Reno, 2008. / "December 2008." Includes bibliographical references. Online version available on the World Wide Web.
36

On redox reactions and transport processes of solutes in coastal marine sediments /

Karle, Ida-Maja. January 2006 (has links)
Thesis (Ph. D.)--Göteborg University, 2006. / Includes bibliographical references.
37

The effect of tidal forcing on iron cycling in intertidal salt marsh sediments

Bristow, Gwendolyn. January 2006 (has links)
Thesis (M. S.)--Earth and Atmospheric Sciences, Georgia Institute of Technology, 2007. / Dr. Emanuele Di Lorenzo, Committee Member ; Dr. Ellery Ingall, Committee Member ; Dr. Martial Taillefert, Committee Chair.
38

Nitrogen, phosphorus and particulate matter budgets of five coniferous forest ecosystems in the western Cascades Range, Oregon /

Fredriksen, R. L. January 1975 (has links)
Thesis--Oregon State University. / Bibliography: p. 117-122. Also available on the World Wide Web.
39

Metal(loid) cycling in mine-impacted sediments of the northern Idaho Coeur d'Alene River basin /

Toevs, Gordon R. January 1900 (has links)
Thesis (Ph. D.)--University of Idaho, 2006. / Abstract. "August 2006." Includes bibliographical references. Also available online in PDF format.
40

Estudo da diversidade e atividade bacteriana em solos de floresta e sob cultivo de cana-de-açúcar

Moreira, Wellington Marcelo Queixas [UNESP] 10 May 2013 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:32:53Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-05-10Bitstream added on 2014-06-13T20:24:16Z : No. of bitstreams: 1 000737544.pdf: 4940477 bytes, checksum: 0101681bb21fe135e941ea5c67aaaadf (MD5) / A composição e a diversidade de comunidades microbianas podem ser usadas como indicadores da qualidade do solo, pois respondem rapidamente às mudanças ambientais. A intensificação da agricultura causa significante perda de diversidade, reduzindo a habilidade do ecossistema resistir a períodos de estresse e efeitos ambientais indesejáveis. Esta redução é mais evidente quando se trata de sistemas de monocultura, impactando os microrganismos e diversos invertebrados, e também reduz a capacidade de auto-regulação do solo. Assim, este trabalho tem como objetivo analisar a diversidade bacteriana em solos de floresta e em solos cultivados com canade- açúcar (Saccharum spp.) em diferentes períodos do ano que possa estar relacionada com a dinâmica dos ciclos biogeoquímicos, bem como um estudo comparativo entre diferentes áreas de cultivo e técnicas de sequenciamento. As amostras de solo foram coletadas no município de Santa Rita do Passa Quatro, SP. Amostras de DNA metagenômico de cada solo foram extraídas e construídas quatro bibliotecas com amplicons do gene 16S rRNA e quatro bibliotecas com amplicons da região V1 e V2 (Vi) do gene 16S rRNA. Um estudo comparativo com sequencias obtidas nas mesmas condições em outra área situada no município de Mococa, SP também foi analisado. Através dos dados obtidos, foi verificado que em solos de Floresta, independente do período do ano e área analisada, os filos bacterianos e a atividade dos organismos em relação aos ciclos biogeoquímicos, permaneceram praticamente inalterados. Este fato pode ser atribuído à estabilidade desde tipo de ecossistema, no qual existe ciclagem constante de nutrientes. Nas amostras de cana-de-açúcar, observou-se variação na frequência dos organismos encontrados em relação a diferentes coletas... / Microbial communities diversity and composition can be used as soil quality indicators, because respond quickly to environmental changes. Agriculture intensification causes significant loss of diversity, reducing the ability of the ecosystem to resist to periods of stress and undesirable environmental effects. This reduction is more evident when dealing with monoculture systems, impacting the microorganisms and several invertebrates, and also reduce the capacity of the soil self regulation. So, this study aims to analyze the bacterial diversity in forest soils and in soils cultivated with sugar cane (Saccharum spp.) in different periods of the year that can be related to biogeochemical cycles dynamic, as well as a comparative study between farming areas and sequencing techniques. Metagenomic DNA samples of each soil were extracted and built four libraries with gene 16S rRNA amplicons and four libraries with amplicons from gene 16S rRNA region Vi. A comparative study with obtained sequences in same conditions in another area situated in the municipality of Mococa, SP was also analyzed. Through the obtained data, it was found that in forest soils, regardless of the period of year and the area analyzed, bacterial phyla and organisms’ activity in relation to biogeochemical cycles, remained practically unchanged. This fact can be assigned to this type of ecosystem stability, in which there is a constant nutrients cycling. In soil samples cultivated with sugar cane, was observed variation in organisms frequency found in relation to different collections...

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