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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.
1

Molecular analysis of methanotroph ecology in Lake Washington sediment /

Auman, Ann Jennifer. January 2001 (has links)
Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves 110-132).
2

The distribution and PAH-degradative potential of Cycloclasticus spp. in the marine environment /

Geiselbrecht, Allison D. January 1998 (has links)
Thesis (Ph. D.)--University of Washington, 1998. / Vita. Includes bibliographical references (leaves [106]-120).
3

Study of dinoflagellate cysts from recent marine sediments of British Columbia

Dobell, Patricia Elda Rose January 1978 (has links)
Viable cysts collected from natural sediments were induced to excyst. Ten cyst-theca relationships, first established elsewhere, were confirmed for British Columbia (B.C.). These were: Gonyaulax tamarensis, Protoperidinium aspidotum, P. claudicans, P. conicoides, P. conicum, P. cf. denticulatum, P. leonis, P. oblongum, and P. punctulatum. Five cyst-theca relationships were established for the first time: Peridiniopsis cf. hainanensis, Protoperidinium sp. nov., P. thorianum, and two apparently new species of Gonyaulax. P. pentagonum was found to have a cyst different from the cyst of this species in the Atlantic. Forty-five samples from Recent sediments were collected along the coast of B.C. Twenty-three of the samples had very few cysts. Hidden Basin was the chief source of viable cysts for the excystment experiments. Ten cyst-based taxa were described from the sediment samples. These were: Operculodinium centrocarpum, the cyst of Scrippsiella faeroense (= Micrhystridium bifurcatum), Spiniferites belerius, S. bentori, S. bulloideus, S. elongatus, S. membranaceus, S. nodosum, and S. ramosus. Tanyosphaeridium sp. has been recorded previously as the cyst of Polykrikos schwarzi. Two new cyst-based taxa are described for the first time. These are a cyst of Protoperidinium sp., and Spiniferites "sp. A". Cyst assemblages in the Recent sediments of B.C. were similar to many temperate estuarine and neritic areas. Some cysts which are characteristic of these areas in other regions, have not yet been found in B.C. The relative importance of some cysts also varies from that found in similar sediments elsewhere. The dominance of Operculodinium centrocarpum in many of the cyst assemblages, including B.C., is a pattern typical of temperate estuarine conditions. Some cysts appear to be characteristically associated with fjord environments. Scrippsiella faeroense, for example, has been found in Norwegian fjords and Scottish sea lochs as well as some B.C. fjords and inlets. / Science, Faculty of / Botany, Department of / Zoology, Department of / Graduate
4

Sedimentary DNA from a submerged site reveals wheat in the British Isles 8000 years ago

Smith, O., Momber, G., Bates, R., Garwood, P., Fitch, Simon, Pallen, M., Gaffney, Vincent, Allaby, R.G. 27 February 2015 (has links)
Yes / The Mesolithic-to-Neolithic transition marked the time when a hunter-gatherer economy gave way to agriculture, coinciding with rising sea levels. Bouldnor Cliff, is a submarine archaeological site off the Isle of Wight in the United Kingdom that has a well-preserved Mesolithic paleosol dated to 8000 years before the present. We analyzed a core obtained from sealed sediments, combining evidence from microgeomorphology and microfossils with sedimentary ancient DNA (sedaDNA) analyses to reconstruct floral and faunal changes during the occupation of this site, before it was submerged. In agreement with palynological analyses, the sedaDNA sequences suggest a mixed habitat of oak forest and herbaceous plants. However, they also provide evidence of wheat 2000 years earlier than mainland Britain and 400 years earlier than proximate European sites. These results suggest that sophisticated social networks linked the Neolithic front in southern Europe to the Mesolithic peoples of northern Europe.
5

The distribution of diatoms in the surface sediments of British Columbia inlets

Roelofs, Adrienne Kehde January 1983 (has links)
The purpose of the study was to examine the distributional patterns of diatoms in the surface sediments of ten southern British Columbia inlets with respect to oceanographic and hydrographic setting, and phytoplankton distribution and productivity. The study area was divided on the basis of inlet type (high, medium, and low runoff), within-inlet gradients, and zones (northern, central, and southern). A small group of species dominated the 95 sediment assemblages. There was a fairly good correlation between the biocoenoses and the thanatocoenoses in the sense that most of those species reported as dominants in the phytoplankton were also dominants in the sediment assemblages. However, there were discrepancies and these could not be explained on the basis of the relative silicification of the diatom valves. Skeletonema costatum, usually considered a weakly-silicified, dissolution-sensitive species, was abundant in British Columbia sediments. Both the pacifica and the aestivalis forms of Thalassiosira aestivalis were abundant in the phytoplankton, but only the pacifica form was preserved well in the sediments. Thalassiosira nordenskioeldii, which is found in other sediment assemblages, was rare in most British Columbia sediments. The distributional patterns of freshwater and marine littoral species appeared to be indicative of river sources entering the estuarine system. The absolute abundance of diatoms in the sediment assemblages increased from the northern to the southern zone. Within the inlets, both absolute abundance and primary productivity increased toward the mouth. Estuarine circulation did not appear to alter substantially the spatial relationship between the biocoenoses and the thanatocoenoses. In general, individual species and species-groups often exhibited distinct distributional patterns which could be related to inlet type, zonal, and within-inlet patterns. In particular, the principal coordinate analysis showed a zonal correlation between the dominant species in the sediment assemblages, and primary productivity, salinity, and temperature in the surface waters. / Science, Faculty of / Botany, Department of / Graduate

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