• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 212
  • 36
  • 29
  • 20
  • 9
  • 8
  • 8
  • 8
  • 8
  • 8
  • 8
  • 7
  • 4
  • 2
  • 2
  • Tagged with
  • 389
  • 51
  • 42
  • 39
  • 37
  • 34
  • 33
  • 32
  • 30
  • 28
  • 28
  • 28
  • 27
  • 27
  • 25
  • 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.
41

Die Diatomeenflora von Neukaledonien Systematik, Geobotanik, Ökologie ein Fazit /

Moser, Gerd. January 1900 (has links)
Presented as the author's Thesis (doctoral)--Johann Wolfgang Geothe-Universitat) under the title: Systematik, geobotanische Sonderstellung und Ökologie der Diatomeen (Bacillariophyceae) von Neukaledonien. / Includes bibliographical references (p. 193-199) and index.
42

Spatial and temporal structure within an epiphytic diatom community on Myriophyllum spicatum L.

Prunty, James Allen. January 1982 (has links)
Thesis (M.S.)--University of Wisconsin--Madison, 1982. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 143-152).
43

Snail grazing effects on the composition and metabolism of benthic diatom communities and subsequent effects on fish growth /

Connor, Michael Stewart. January 1980 (has links)
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Biology, 1980. / Supervised by John M. Teal. Vita. Includes bibliographical references.
44

Diatoms in the Eocene and Oligocene sediments off NW-Africa : their stratigraphic and paleogeographic occurrences /

Fenner, Juliane, January 1981 (has links)
Thesis (doctoral)--Christian-Albrechts-Universität zu Kiel, 1981. / Vita. Includes bibliographical references (p. 137-154).
45

The influence of nutrients on surf-zone phytoplankton

Wolmarans, Karien January 2012 (has links)
The variability in surf-zone phytoplankton community composition together with variability in nutrient concentrations was studied at seven beaches along the coast near Port Elizabeth, South Africa over a one-year sampling period. The nutrient requirements of selected diatoms and dinoflagellates that co-occur at these beaches were studied. The highest nutrient concentrations were recorded at Brighton beach, with phosphate concentration being substantially higher than standards set out for both South African and European waters. Nitrate, ammonium and silicate concentrations were consistent (low variability) at all beaches. The species composition of beaches without surf diatoms was also not variable (except for King’s Beach – an artificial beach). Maitland beach was the only beach that could be identified as a surf diatom beach due to the presence of Anaulus australis. The surf diatom Anaulus australis was found to be a superior competitor compared to all other species tested: the other surf diatom Asterionellopsis glacialis, and the dinoflagellates Gonyaulax spinifera, Prorocentrum micans, and Scrippsiella trochoidea. Gonyaulax spinifera could possibly outcompete Anaulus australis in systems should nitrate become limiting.
46

The use of species diversity and evenness indices for investigating the effects of water quality on diatom communities /

Law, Chi-yuen. January 1982 (has links)
Thesis (M. Phil.)--University of Hong Kong, 1983.
47

Silicon biogeochemistry in the open-ocean surface waters : insights from the Sargasso Sea and equatorial Pacific /

Krause, Jeffrey W. January 1900 (has links)
Thesis (Ph. D.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 173-191). Also available on the World Wide Web.
48

Diatom-inferred records of paleolimnological change and Holocene paleoclimate variability from the Altai Mountains (Siberia) and Columbia Mountains (British Columbia)

Westover, Karlyn Sara. January 1900 (has links)
Thesis (Ph.D.)--University of Nebraska-Lincoln, 2006. / Title from title screen (site viewed on September 12, 2006). PDF text of dissertation: viii, 148, [323] p. : ill. ; 21.65Mb. UMI publication number: AAT 3208120. Includes bibliographical references. Also available in microfilm and microfiche format.
49

Studies on the ecology and systematics of the diatoms (Bacillariophyta) from some South Africa rivers

Archibald, Robert Eldred Mostert January 1969 (has links)
This report contains the results of some ecological and systematic studies on the diatoms from the Vaal Dam catchment area in the Transvaal, and the Bloukrans River in the Eastern Cape Province. In Part 1 the effects of high concentrations of nitrogen were studied in relation to the composition of the diatom associations. Water samples from four stations on the Bloukrans River were analysed chemically at certain intervals during the months of April and August 1967. Diatom samples collected from these stations at the beginning and end of each of these sampling periods were subjected to a "Thomasson Analysis" to determine the relative densities of the various species in the diatom associations. A statistical analysis of the results reflected a poor but positive correlation between the two variables, i.e. high numbers of nitrogen heterotrophic Nitzschiae were correlated with high concentrations of nitrogen, while low numbers were correlated with low concentrations. Part 2 presents the results of the ecological studies on the diatom associations of the Vaal Dam Catchment Area. In this section the diatom associations from each sampling point or station were subjected to a "Thomasson Analysis" to determine the relative densities of the different species in the associations. Employing already known correlations between environment and association, the results of this analysis were discussed and the ecological conditions for each sampling station were assessed. The associations were similar in composition over the entire catchment area, and indicated on the whole water of good quality. Points of pollution were detected, but were generally localised and the effects of the pollution were soon removed. Only the Waterval River showed evidence of more constant pollution. The associations provided evidence for some seasonal variation in their composition. Finally in Part 3 the systematics and taxonomy of the diatoms in the Vaal Dam catchment area are discussed. References are made to the original and more recent descriptions of each species found in this study, and a list of synonyms is given wherever 'possible. Comments on the systematics, taxonomy and autecology of each species are given, and the distribution of the species in South Africa and the Vaal Dam catchment area is discussed. A number of species, varieties and forms have been recorded for the first time in South Africa. During the course of this study 20 species have been described as new to science; the descriptions of some have been published, while the descriptions of the others will be published formally in the future. All species described as new or having interesting features are illustrated in the plates.
50

The diatom flora of the Provo River, Utah

Lawson, Laurie Linwood 01 April 1974 (has links)
The present study was undertaken to investigate the diatom flora of a major river in northern Utah, to determine the diatom species present, and to illustrate them in a manner useful for future diatom researchers in the intermountain region. It is hoped that this work will aid in algal productivity, ecological, and taxonomic studies of Rocky Mountain streams and rivers.

Page generated in 0.0222 seconds