Thesis (Ph. D.)--University of Wisconsin--Madison, 1971. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

The production and removal of anaerobiotic compounds, principally ethanol from flooded tree roots was examined in lodgepole pine (Pinus contorta) from known provenances. Contrary to earlier suggestions, the gaseous pathway, with ethanol exiting from the tree through the lenticels, removes only a very small proportion (less than 0.2%) of the ethanol generated in the flooded roots. The transpiration stream provides the major route for ethanol transport from the roots. Although the lenticels do not contribute significantly to the removal of ethanol from tree roots, analysis of the gas exiting from them provides a sensitive indicator of the existence of oxygen within roots. Within the xylem sap and root tissue, changes in ethanol, amino acid (alanine, alpha amino butyrate and glutamine) and organic acid (malate and shikimate) composition under flooded conditions were analysed and discussed. For example during flooding glutamine (the major constituent amino acid) was shown to decrease, and alanine and alpha amino butyrate to increase. From the data obtained it was concluded that the health and the metabolism of the root tissue during flooding can be diagnosed by examination of the xylem sap.

The in situ productivity of both the phytoplankton and the macro- phytes in Marion Lake, B.C., was determined from April 1966 through September 1966, by using ¹⁴C techniques. The uptake of NaH¹⁴CO₃ was measured in selected macrophytes by enclosing them in plexiglass chambers. These plants were then combusted in oxygen, and the ¹⁴CO₂ was absorbed in toluene-POPOP-ethanolamine. Radioassay was accomplished by liquid scintillation. In addition to the ¹⁴C method, an organic weight method was used to measure macrophytic productivity. The productivity of the macrophytes was always higher than that of the phytoplankton. There was a considerable difference in the estimates of the macrophyte productivity arrived at by the two different methods, and reasons for this are discussed. The total productivity of the lake is very low when compared with lakes of similar latitudes because of low phytoplankton productivity. It is concluded that in Marion Lake the macrophytes are more important primary producers than the phytoplankton. The difficulty of comparing data between this and other studies is discussed, and the need for standardization of methods is emphasized. / Science, Faculty of / Zoology, Department of / Graduate

No description available.

Thesis (M.S)--University of Wisconsin--Stevens Point, 2002. / Includes bibliographical references (leaves 102-110).

The general goal of this thesis was to examine and quantify the role of rooted submerged aquatic macrophytes in the cycling of metals in the littoral zone. An empirical study using data from an extensive literature survey showed that aquatic plants do not differ markedly in element composition from the sediments in which they grow, and that during uptake the plant's roots do not discriminate between elements essential and not essential for growth. The organic content, pH and redox potential of the sediments were shown to affect the bioavailability of metals to the plants. Biomass density was used to categorize species to assess broad patterns in plant-sediment metal relationships. It was found that the presence/absence of an understory contributed variation to the plant-sediment metal relationships. The role of rooted macrophytes as vectors for various elements between the sediments and attached epiphyte was quantified by growing Myriophyllum spicatum in radio-labelled sediments. This species was found to be a link between the sediments and attached epiphytes for the 4 elements studied (Co, Cs, Eu and Mn). Finally, the export of dissolved metals from weedbeds during plant senescence was quantified using a mass balance approach. It was found that approximately 15% to 30% (depending on the metal) of the metal inventory of the plants at maximum seasonal biomass was lost as dissolved compounds during senescence. During the growing season the macrophyte beds were net sources of metals to the lake, but were net sinks annually.

Thesis (M.S.)--University of Wisconsin--Stevens Point., 2007 / Includes bibliographical references (leaves 102-112).

Thesis (Honors)--Liberty University Honors Program, 2007. / Includes bibliographical references. Also available through Liberty University's Digital Commons.

Thesis (M.S.) -- Central Connecticut State University, 2007. / Thesis advisor: Peter A. Kyem. "... in partial fulfillment of the requirements for the Master of Science degree in Geography." Includes bibliographical references (leaves 112-117). Also available via the World Wide Web.

The species composition, primary productivity and relative abundance of the plankton organisms in Marion Lake, British Columbia were recorded at biweekly intervals for two months following artificial enrichment with nitrate or phosphate or both, of six large wooden enclosures within the lake in four seasons during the year. Enrichment resulted initially in a decrease in diversity and an increase in the productivity of the phytoplankton and standing crop of the entire plankton community. These events were collectively termed a "regressive succession" because their "direction" of change was the reverse of that normally encountered in primary and secondary successions. The regressive succession terminated following algal bloom formation, and diversity began to increase slowly while the primary productivity and standing crop of the plankton dropped. This was indicative of the beginning of a secondary succession in which one group of dominant species was replaced by another and then others in turn replaced these. This successional pattern occurred regardless of season, prevailing physical, chemical, or climatological factors. Thus, such a pattern appeared to be a very general one and was disrupted only by the physical removal of the majority of the planktonic species from the lake resulting from persistent and heavy rains which "flushed" the lake. A statistical analysis of each of the 167 euplankton species observed in the lake was performed using the data from each of the four enrichment series to determine which species responded significantly to artificial enrichment. The individual response patterns were nearly as diverse as the species themselves, however, one of the most common responses was made by very rare species which "bloomed" two to three weeks after nutrient addition. Few primary producers responded to more than one type of nutrient enrichment in any one season which emphasized the importance of Liebig’s Law of the Minimum. The higher trophic levels, on the other hand, responded more to the increase in standing crop in the different enclosures than to any one particular type of nutrient enrichment. The Shannon-Weaver formula, H =nP, log P, was modified by changing the definition of Pi, that is, the individuals in the ith species divided by the total number in the sample. This index was insensitive to changes in the relative abundance of the planktonic species from the higher trophic levels. Pi was redefined so that it was less sensitive to number and more sensitive to both relative biomass and relative productivity. This new index of diversity (Hp ) did not act selectively on the different trophic levels represented in the plankton samples. An understanding of the principles governing community organization and biotic succession should be based on the life history of the individual species comprising the community and not on assumptions about supposed trophic changes. This study indicated that pertinent information about the changes in the structure of a planktonic community could be gained from an analysis of the changes in the relative abundance of each of the species without artificially isolating and culturing these species and without lumping all the organisms into vague trophic categories. / Science, Faculty of / Zoology, Department of / Graduate