Spelling suggestions: "subject:"great makes"" "subject:"great takes""
71 |
Effects of Air Temperature and Lake Ice on Snowfall on the South Shore of Lake SuperiorMaki, Angela Pelkie 15 May 2009 (has links)
Lake Superior is a forcing factor for local weather systems, causing substantial amounts of lake effect snow in the winter (particularly on the south shore). This study assesses decreasing ice cover of Lake Superior and its effects upon synoptic weather factors. Data were collected from eleven National Weather Service (NWS) stations located on the south shore of the lake. Rainfall and snowfall amounts from December to May were regressed on percent ice coverage and average monthly temperatures from 1972-2002. Ice coverage and average monthly temperature had a negative relationship with snowfall and rainfall.
|
72 |
Long Term Trends in Lake Michigan Wave ClimateNicholas R Olsen (6592994) 10 June 2019 (has links)
Waves are a primary factor in beach health, sediment transport, safety, internal nutrient loading, and coastal erosion, the latter of which has increased along Lake Michigan's western coastline since 2014. While high water levels are undoubtedly the primary cause of this erosion, the recent losses may also be indicative of changes in the lake's wind-driven waves. This study seeks to examine long-term trends in the magnitude and direction of Lake Michigan waves, including extreme waves and storm events using buoy measurements (National Data Buoy Center Buoys 45002 and 45007) and the United States Army Corps of Engineers Wave Information Study (USACE WIS) wave hindcast.<br><br>Tests show significant long-term decreases in annual mean wave height in the lake's southern basin (up to -1.5mm/yr). When wave-approach direction was removed by testing directional bins for trends independently, an increase in the extent of the affected coast and rate of the shrinking waves was found (up to -4mm/yr). A previously unseen increasing trend in wave size in the northern basin (up to 2mm/yr) was also revealed.<br><br>Data from the WIS model indicated that storm duration and peak wave height in the southern basin has decreased at an averaged rate of -0.085hr/yr and -5mm/yr, respectively, from 1979 to 2017. An analysis of the extreme value distribution's shape in the southern basin found a similar pattern in the WIS hindcast model, with the probability of observing a wave larger than 5 meters decreasing by about -0.0125yr<sup>-1</sup>. In the northern basin, the probability of observing a wave of the same size increased at a rate of 0.0075yr<sup>-1</sup>.<br><br>The results for trends in the annual means revealed the importance of removing temporal- and spatial-within-series dependencies, in wave-height data. The strong dependence of lake waves on approach direction, as compared to ocean waves, may result from the relatively large differences in fetch length in the enclosed body of water. Without removal or isolation of these dependencies trends may be lost. Additionally, removal of the seasonal component in lake water level and mean wave-height series revealed that there was no significant correlation between these series.
|
73 |
Ecological Factors Controlling Microcystin Concentrations in the Bay of Quinte, Maumee Bay, and Three Grand River ReservoirsYakobowski, 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.
|
74 |
Modeling the growth dynamics of <em>Cladophora</em> in eastern Lake ErieHiggins, 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 (≤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.
|
75 |
Ecological Factors Controlling Microcystin Concentrations in the Bay of Quinte, Maumee Bay, and Three Grand River ReservoirsYakobowski, 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.
|
76 |
Distribution and Abundance of Larval Lake Whitefish (Coregonus clupeaformis) in Stokes Bay, Lake HuronRyan, 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)
|
77 |
A Call for Bioregional Governance in Cascadia: Shaping an Ecological Identity in the Land of Falling WatersFreed, 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.
|
78 |
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>
|
79 |
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).
|
80 |
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.
|
Page generated in 0.0554 seconds