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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.
71

Modeling the growth dynamics of <em>Cladophora</em> in eastern Lake Erie

Higgins, Scott January 2005 (has links)
<em>Cladophora glomerata</em> is a filamentous green alga that currently forms extensive blooms in nearshore areas of Lake Ontario, eastern Lake Erie, Lake Michigan, and isolated locations in Lake Huron. The biomass, areal coverage, algal bed characteristics, and tissue phosphorus concentrations of <em>Cladophora glomerata</em> were measured at 24 nearshore rocky sites along the northern shoreline of Lake Erie?s eastern basin between 1995-2002. Midsummer areal coverage at shallow depths (&le;5m) ranged from 4-100 %, with a median value of 96%. Peak seasonal biomass ranged from <1 to 940 g m<sup>-2</sup> dry mass (DM), with a median value of 171 g m<sup>-2</sup> DM. Tissue phosphorus varied seasonally, with initial high values in early May (0. 15 to 0. 27 % DM; median 0. 23 % DM) to midsummer seasonal low values during peak biomass (0. 03 to 0. 23 % DM; median 0. 06 % DM). A numerical <em>Cladophora</em> growth model (CGM) was revised and field-tested at 5 sites in eastern Lake Erie during 2002. The CGM is useful for: 1) Predicting <em>Cladophora</em> growth, biomass, and tissue phosphorus concentrations under non-point source P loading with no depth restrictions; 2) providing estimates of the timing and magnitude of the midsummer sloughing phenomenon; 3) determining the contribution of <em>Dreissena</em> invasion to the resurgence of <em>Cladophora</em> in eastern Lake Erie; and 4) developing management strategies for <em>Cladophora</em> abatement. The CGM was applied to investigate how the spatial and temporal patterns of <em>Cladophora</em> growth were influenced by the natural variability in environmental parameters in eastern Lake Erie. Seasonal patterns in <em>Cladophora</em> growth were strongly influenced by temperature, and peak depth-integrated biomass was strongly influenced by both available light and phosphorus. The photosynthetic capacity of field collected <em>Cladophora</em> was a poor predictor of the mid-summer sloughing phenomenon. The CGM, however, predicted that self-shading within the dense <em>Cladophora</em> mats would have caused negative growth rates at the base of the dense mats for 14 days prior to the sloughing event. The metabolic imbalances at the base of the <em>Cladophora</em> mats were driven primarily by the availability of light and were exacerbated by intermediate water temperatures (~23°C). The excellent agreement between model simulations and field data illustrates the ability of the CGM to predict tissue P and growth over a range of sites and depths in eastern Lake Erie and suggests potential for the model to be successfully applied in other systems.
72

Ecological Factors Controlling Microcystin Concentrations in the Bay of Quinte, Maumee Bay, and Three Grand River Reservoirs

Yakobowski, Sarah Jane 01 1900 (has links)
Certain types of cyanobacteria have the potential to produce toxins including microcystin, a hepatotoxin. Toxic cyanobacterial blooms are becoming increasingly common worldwide. They are a concern in the Great Lakes and surrounding waters. In this study, Lake Ontario’s Bay of Quinte, Lake Erie’s Maumee Bay, and three reservoirs along the Grand River were studied. Environmental variables, cyanobacterial biomass inferred from the Fluoroprobe, and microcystin concentrations were measured. In 2005 the three reservoirs, Belwood Lake, Conestogo Lake, and Guelph Lake were sampled every two weeks from July to September. Belwood Lake was also sampled in October when a cyanobacterial bloom occurred. In 2006 the Bay of Quinte was sampled twice, in July and September, and Maumee Bay was sampled twice, in June and August. Physical variables measured included water transparency and temperature. All species of nitrogen (N) and phosphorus (P) were measured, along with extracted chlorophyll a and particulate carbon (C), N, and P. The distribution of chlorophyll and major algal groups throughout the water column was profiled in situ using a spectral fluorometer (Fluoroprobe).Variable fluorescence of phytoplankton was assessed using Pulse Amplitude Modulated (PAM) fluorometry to measure photosynthetic parameters. Phytoplankton counts were performed on selected samples from the Bay of Quinte and Maumee Bay. Total and dissolved microcystin were measured using the protein phosphatase inhibition assay (PPIA). PPIA was chosen over alternative detection methods because it is a functional assay that measures the level of microcystin in a sample via the amount of protein phosphatase inhibition that it exerts. This yields ecologically relevant data as protein phosphatase inhibition is the main mode of microcystin toxicity. The PPIA formulation used in our lab was based on variations in the literature that use unconcentrated water samples directly in the assay. The assay was optimized to employ both a higher and lower standard curve through the use of two enzyme concentrations. The lower enzyme concentration allowed the method detection limit to be decreased to 0.05 µg/L to accommodate our low-microcystin samples. In the Bay of Quinte, microcystin levels were higher in July 2006 (total mean=2.25 μg/L ) than in September 2006 (total mean=0.58 μg/L). In July a cyanobacterial bloom consisting of 97% Microcystis spp. was present. In September 83% of the cyanobacterial biomass was composed of Anabaena spiroides and only 8% was Microcystis spp. In the Bay of Quinte elevated microcystin concentrations were associated with higher soluble reactive P levels, lower seston C:P molar ratios, and lower total N. In Maumee Bay microcystin levels were higher in August 2006 (total mean= 4.45 μg/L) than they were in June 2006 (<0.05 μg/L). In August a cyanobacterial bloom consisting of 22% Microcystis spp. and 48% Aphanizomenon flos-aquae was observed. Higher microcystin concentrations in Maumee Bay were associated with decreased total N: total P molar ratios, increased total P, and decreased water transparency as measured by Secchi depth. Belwood Lake had the highest microcystin levels of the three reservoirs but only once exceeded the recommended World Health Organization concentration of 1.0 μg/L. Belwood Lake’s largest cyanobacterial bloom in October 2005 was accompanied by relatively low microcystin levels (<0.2 μg/L). Conestogo and Guelph lakes always had microcystin levels below 0.2 μg/L and 0.6 μg/L, respectively. In the Grand River reservoirs, increased microcystin concentrations were associated with higher chlorophyll a, higher light attenuation coefficients, lower total N, lower total N: total P molar ratios, higher C:P molar ratios, lower nitrate, higher cyanobacterial biomass, and higher total P. When data from the Bay of Quinte, Maumee Bay, and Grand River reservoirs were pooled, total microcystin had the most significant positive correlation with total P. Total microcystin and water temperature also had a significant positive correlation.
73

Distribution and Abundance of Larval Lake Whitefish (Coregonus clupeaformis) in Stokes Bay, Lake Huron

Ryan, Kathleen 29 November 2012 (has links)
Lake whitefish (Coregonus clupeaformis) are an ecologically, culturally and economically important species throughout the Great Lakes. Studying the larval period of ontogeny is important to increasing knowledge of population dynamics and monitoring ecological changes in lake whitefish populations. Larval lake whitefish have been studied across the Great Lakes since the 1930’s; however, there are major gaps in our understanding of the factors that affect distribution and abundance of larval lake whitefish. The goal of this study was to investigate the distribution and abundance of larval lake whitefish in a Great Lakes embayment, using Stokes Bay, Lake Huron as a case study. Plankton samples and environmental data were collected from mid-spring to early summer during 2011 and 2012. Plankton tows in 2011 (n=71, 21 April-03 June) revealed relatively high densities of larval lake whitefish as compared to other Great Lakes studies. Overall there was little relationship between environmental variables (temperature, dissolved oxygen, conductivity, depth) and larval lake whitefish distribution and abundance. Plankton tows in 2012 (n=25, 25 April-23 May) revealed a virtual absence of larval lake whitefish in Stokes Bay. The apparent 2012 year-class failure was concurrent with unseasonably warm temperatures and reduced ice coverage. Temperature-related hypotheses are evaluated in context with other possible explanations of a general year-class failure of lake whitefish during early life history. / Saugeen Ojibway Nation (SON)
74

A Call for Bioregional Governance in Cascadia: Shaping an Ecological Identity in the Land of Falling Waters

Freed, Molly D 01 January 2015 (has links)
In recent years, as globalization has taken a toll on North Americans’ “sense of place,” there has been a swelling interest in the identification of bioregions: spaces delineated by their natural borders and shaped by the cultures that arise within them. Bioregionalism, the movement that arose from this scalar shift, emphasizes the “reinhabitation” of bioregions through a deep understanding and attachment between residents and their watershed and habitat. This thesis argues for a shift to bioregional-scale environmental governance in the Cascadian bioregion (the Pacific Northwest) via an interstate compact. Using the Great Lakes bioregion as a comparable case study, this thesis goes on to examine the effects of neoliberalization on two resulting cross-border institutions, the Great Lakes Commission and the Council of the Great Lakes Region. It ultimately concludes that a shared ecological identity is imperative for preserving the ethos of bioregionalism in future policymaking, rather than just the scale. In an effort to create a tangible path towards the shaping of this identity, a communications framework is presented. Based on lessons from the Great Lakes case studies, this framework utilizes “condensation symbols” and the “triple appeals principle” as possible tools for Cascadian activists to leverage moving forward.
75

Improving compliance with international human law by non-State armed groups in the Great Lakes region of Africa.

Kaneza, Carine January 2006 (has links)
<p>Currently, one of the most dramatic threats to human security is constituted by internal armed conflicts. In 1998, violent conflicts took place in at least 25 countries. Of these armed conflicts, 23 were internal, engaging one or more non-State armed groups. A crucial feature of internal conflicts is the widespread violation of humanitarian law and human rights by armed groups, from rebel groups to private militias. This thesis aimed at identifying various ways of promoting a better implementation of the Geneva Conventions and its Protocols by NSAGs in the Great Lakes Region.</p>
76

The benefit of the gift exchange and social interaction in the Late Archaic western Great Lakes /

Hill, Mark A. January 2009 (has links) (PDF)
Thesis (Ph. D.)--Washington State University, May 2009. / Title from PDF title page (viewed on June 10, 2009). "Department of Anthropology." Includes bibliographical references (p. 290-311).
77

The Great Lakes and human health : an interpretive environmental policy analysis /

Iannantuono, Adele. January 1900 (has links)
Thesis (Ph. D.)--McMaster University, 2001. / Includes bibliographical references (leaves 234-244). Also available via World Wide Web.
78

Soil testing and nutrient application practices of agricultural retailers in the Great Lakes Region

Sisung, Theresa January 1900 (has links)
Master of Agribusiness / Agricultural Economics / Terry Griffin / Agricultural runoff containing phosphorus is believed to be a major contributor of algae blooms in the Western Lake Erie Basin. However, the implementation of best management practices (BMPs) can be used to help reduce the runoff of phosphorus. This research involved conducting surveys to analyze the current implementation of BMPs in Michigan and Indiana. The hypothesis is that the survey results are similar between the two states. An additional hypothesis is that the Michigan and Indiana results are similar to results from two other studies that were previously conducted. The results from this research generally support the hypothesis that a similar number of farmers in Michigan and Indiana are already implementing best management practices on their farms. In addition to the results being similar across Michigan and Indiana, there is also some evidence that shows that the results are similar to studies from the Ohio State University (LaBarge and Prochaska 2014), CropLife magazine (Erickson and Widmar 2015) and NRCS (U.S. Department of Agriculture, Natural Resources Conservation Service 2016); however upon further investigation there are distinct differences before and after media mentions of ramifications from the Lake Erie algal blooms. While it is difficult to force farmers to implement BMPs, the results of this study may help to educate them, which may cause them to add these practices to their operations.
79

Évolutions des tactiques rebelles et de leurs conséquences humanitaires dans les Grands lacs d'Afrique entre 1981 et 2013

Plauchut, Agathe 02 December 2016 (has links)
Ce travail cherche à comprendre en quoi les causes de l’instabilité sécuritaire de la région des Grands Lacs sont rationnelles et interdépendantes, en dépit d’explications simplistes largement répandues (déterminisme ethnique, violence endogène, cupidité, etc.). Il s’agit donc d’identifier ces causes, pour saisir les mécanismes des conflits récurrents qui secouent la région dans notre période d’étude. Nous entendons ainsi étudier la modernité du phénomène insurrectionnel en Afrique, en nous attachant à l’analyse de ses différentes expressions dans la région des Grands Lacs, qui a hébergé de 1981 à 2013 des exemples empruntant à toutes ses évolutions contemporaines / This work seeks to understand how the causes of chronic insecurity in the Great Lakes region are both rational and interdependent, despite widespread simplistic explanations (ethnic determinism, endogenous violence, greed, etc.). We intend to identify these causes to better understand the mechanisms behind the recurring conflicts that shook the region in the period under study. In doing this, we gain greater understanding of contemporary insurrectionary practices and the evolutions of guerrilla tactics in Africa through their expression in rebel movements in the Great Lakes between 1981 and 2013
80

The International Joint Commission, with special emphasis on the Great Lakes water quality agreement : a view from the Canadian side

Boettcher, Jens January 1977 (has links)
The International Joint Commission was instituted under the Boundary Waters Treaty of 1909; it held its constitutive meeting in 1912. The prime purpose of this organization is to prevent or settle Canadian -U.S. boundary waters - and certain other - disputes. The functions and powers the Commission was given under the 1909 Treaty are divided into four categories: administrative, quasi-judicial, arbitral, and investigative and advisory. The administrative functions were restricted to a then controversial group of boundary waters in the prairies. In its quasi-judicial capacity, which accounted for the majority of its work in the first half of its existence, the Commission is empowered to grant or withhold permission for certain planned endeavours - public or private - that would affect boundary waters. Thus far, the services of the Commission in its arbitral capacity have not been called upon. In recent years most of the Commission's work has resulted from matters referred to it by the two federal Governments for investigation and advisory opinion. In its most comprehensive endeavour yet the Commission, at the request of the two Governments in 1964, investigated and reported upon pollution in the lower Great Lakes and the international section of the St. Lawrence River. The Commission's final findings and recommendations, published in December, 1970, provided the basis for the Great Lakes Water Quality Agreement, entered into by Canada and the United States sixteen months later. The Agreement is a comprehensive and detailed pollution abatement programme, based upon laid down water quality objectives. It gives the Commission certain, primarily surveillance powers wiith regard to Great Lakes pollution without, however, changing the fundamental structure of its functions and powers. Though the clean-up of the Great Lakes is taking considerably longer than expected the two signatory countries can, according to the wording of the Agreement, hardly be held liable for breach of treaty. A comparison with several international commissions concerned with water resources reveals that the performance record of the International Joint Commission is decidedly superior to that of the others. This can be attributed to certain extrinsic advantages which it has over its counterparts, such as the number of countries involved, their political, cultural and economic proximity, and the geographically balanced location of the boundary waters, as well as to the way in which it has conducted its business, thus building up a respectable reputation over the years. Nevertheless, the Commission can ill afford to rest on its laurels. There remains considerable room for improvement in its operations. Moreover, major decisions concerning its future structure as well as a reassessment of its future role will have to be made in the near future. The final part of this thesis examines 1. whether the size of the Commission itself should be increased or whether the present six Commissioners should, instead, all serve on a full-time basis; the!latter is preferred; 2. whether the Commission should, or should not move towards becoming an international Great Lakes environmental administrative authority; basically, it should not; 3. the extent to which the public can participate in the work of the Commission. / Law, Peter A. Allard School of / Graduate

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