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<p> During the summer of 1970 a study was initiated to define factors controlling the biosphere in the lentic environment of the Precambrian Shield. Data were collected from nine lakes of varying size and depth located in a number of geological formations. Chemical, physical and biological conditions in these lakes were investigated at two sampling periods and the lakes were classified on the basis of morphology (surface area to volume area) and lithology (surficial and bedrock geology). Attempts were made to determine the influence of morphology and lithology on the chemical and biological conditions observed. Emphasis was placed on the relationships of these factors to aspects of the primary and secondary trophic levels in the lentic ecosystem including primary productivity and the standing crop and diversity of phytoplankton and zooplankton.</p> <p> The atmosphere, a third potential factor influencing lakes was investigated by means of a network of air monitoring stations (collecting both precipitation and 'dry fallout') located throughout the greater Sudbury area.</p> <p> The results of the study indicated that: 1. the lentic ecosystem in the Precambrian Shield area studied can be defined by simple chemical and physical variables. 2. the morphology of the lake basins (surface area to volume ratio) modified by lithology (primarily the presence or absence of limestone) is the major factor influencing biological activity. Lakes with a low surface area to volume ratio showed low productivity while lakes with a high surface area to volume ratio showed nigh productivity. Silica and calcium concentrations (influenced by the lithosphere) were important since relatively small changes in the concentration of these chemical species stimulated a response in the biosphere. 3. some of the lakes were affected by concentrations of sulphates conveyed to the water by the atmosphere. Observed effects included increases in the hydrogen ion concentration in lakes with low calcium concentrations (poorly buffered) and a depression of the diversity of both primary and secondary trophic levels.</p> / Thesis / Master of Science (MSc)

The inherent complexity of the natural world has long been a central theme in ecological research, as the patterns and processes that govern ecosystems can operate at multiple spatial and temporal scales. It is clear that to develop general ecological frameworks, we must consider many different factors at different scales, and incorporate ideas from other disciplines. This thesis touches on several of these ideas, first through an analysis of literature, and then with field research examining the role of broad-scale abiotic factors on lotic systems. To determine how integrated aquatic science is currently understood among different researchers, I provide an analysis on communication and exchange of ideas among various subfields in aquatic science. I show that there are clear divisions within the aquatic science literature, suggesting that there is progress to be made on the integration of methods and ideas. Next, I examine the impact of a large-scale geological feature, the Canadian Precambrian Shield, on abiotic conditions in lotic systems, and how these conditions in turn influence the species assemblages of aquatic organisms. This is addressed with both historical survey data, as well as contemporary data, and as a whole, incorporates ideas concerning the relative influence of regional versus local factors, the importance of historical factors on species distributions, and the relationship between the abiotic environment and biological communities. These analyses show that there are distinct fish and macroinvertebrate communities in Shield lotic systems compared to those found in nearby off-Shield sites, indicating that the Shield is an important broad-scale factor influencing local biological communities. This finding, in conjunction with previous knowledge on the influence of historical factors, provides further insight on the structuring of lotic fish and macroinvertebrate communities in Ontario.

The inherent complexity of the natural world has long been a central theme in ecological research, as the patterns and processes that govern ecosystems can operate at multiple spatial and temporal scales. It is clear that to develop general ecological frameworks, we must consider many different factors at different scales, and incorporate ideas from other disciplines. This thesis touches on several of these ideas, first through an analysis of literature, and then with field research examining the role of broad-scale abiotic factors on lotic systems. To determine how integrated aquatic science is currently understood among different researchers, I provide an analysis on communication and exchange of ideas among various subfields in aquatic science. I show that there are clear divisions within the aquatic science literature, suggesting that there is progress to be made on the integration of methods and ideas. Next, I examine the impact of a large-scale geological feature, the Canadian Precambrian Shield, on abiotic conditions in lotic systems, and how these conditions in turn influence the species assemblages of aquatic organisms. This is addressed with both historical survey data, as well as contemporary data, and as a whole, incorporates ideas concerning the relative influence of regional versus local factors, the importance of historical factors on species distributions, and the relationship between the abiotic environment and biological communities. These analyses show that there are distinct fish and macroinvertebrate communities in Shield lotic systems compared to those found in nearby off-Shield sites, indicating that the Shield is an important broad-scale factor influencing local biological communities. This finding, in conjunction with previous knowledge on the influence of historical factors, provides further insight on the structuring of lotic fish and macroinvertebrate communities in Ontario.

As part of the collaborative Dorset Research Project investigating mercury and energy fluxes in fresh-water lakes, I measured mercury in the seston (Chapter 1) and studied the biomanipulation impacts on the phytoplankton (Chapter 2) of two Precambrian Shield lakes. Sestonic-mercury (HgT) was measured in the metalimnion and hypolimnion of each lake throughout the summer of 1995 to determine seasonal fluctuations and the relationship with algal productivity. In each lake, sestonic-HgT (pg Hg/L) did not significantly change in the metalimnion but significantly increased in the hypolimnion by season's end. Combined influences of external HgT inputs, seston sedimentation and increased methylmercury production in the hypolimnia over the season may have contributed to these trends. In comparison to other variables measured, algal productivity was highly correlated with sestonic mercury concentrations in both lakes at each limnetic depth. Although there were no significant differences between lakes with respect to average weight-specific HgT (pg HgT/mg D.W.), chlorophyll a exhibited the best correlations with HgT in MouseL. whereas algal biomass was more highly correlated with HgT in Ranger L. This disparity between lakes may be the result of apparent inter-lake differences in light availability and algal community structure. It was also apparent that changes in the proportions of large and small cells over the season affected the magnitude of sestonic mercury measured. With respect to the potential for trophic transfer of mercury, I suggest that small edible algal cells may bioconcentrate more mercury per unit weight than larger, inedible ones. The data also indicate that seston samples should be collected throughout the season at discrete depths if sestonic-mercury measurements are to be used in trophic transfer models. I also examined the effects of fish biomanipulation on the phytoplankton community of these study lakes. Prior to the biomanipulation, Ranger L. had a top-piscivore community whereas Mouse L. had a top-planktivore community. The biomanipulation involved the removal of top-piscivores from Ranger L. and adding top-piscivores to Mouse L. Trophic Cascade theory predicts that algal biomass in these lakes, with their similar morphometries and resource characteristics, should be ultimately controlled by top-consumer abundance. In addition, model predictions expect "edible" algal size-classes and groups in the community to experience the greatest changes in abundance. Therefore in Ranger L., it was expected that the removal of piscivores would result in higher algal biomass (particularly edible algae), whereas the addition of piscivores in Mouse L. would result in lower algal biomass (particularly edible algae). However, for those years following the biomanipulation, algal biomass significant increased in both lakes compared to pre-manipulation years. This suggests that variables other than direct trophic forces were controlling algal biomass from year to year, regardless of changes in the fish communities. When algal size-classes were tested, only edible cells varying from 10-30 μm increased in Mouse L., contrary to what was predicted. In Ranger L., large cells and colonies > 30 μm unexpectedly increased when all other size-classes did not significantly change. With respect to algal group composition, both Greens and Cryptomonads significantly increased in Mouse L. whereas only Greens significantly increased in Ranger L.. Both of these groups were considered to be edible and thus these results were not consistent with the model predictions. As such, I suggested that "bottom-up" influences were important in controlling both size-class and taxonomic abundances. However, when individual size-classes of representative algal genera were compared between pre-and post-manipulation years, there were some effects which may be attributed to the biomanipulation. In particular, large Green colonies became prevalent in Mouse L. during post-manipulation years as a probable response to increased grazing pressure. Conversely, "edible" Greens became prevalent in Ranger L. after the biomanipulation, supporting the prediction of reduced zooplankton grazing pressure. These results have revealed the necessity to test specific algal genera of varying size-classes in order to detect the effects of biomanipulation. They also showed that the majority of algal genera, regardless of size, were not affected by the biomanipulation. Limitations to my interpretation of the data are discussed and vary from time-scale issues to consumer and resource availability unknowns. Along with recommendations for further studies in this area, I hypothesized that the trophic transfer of sestonic-mercury to zooplankton could be intensified if small, edible algal genera (shown to be impacted by Top-Down forces), have relatively higher weight-specific mercury concentrations. However, considering that the phytoplankton community as a whole has shown resilience to herbivory, I also suggest that the majority of mercury measured in the seston is not available for trophic transfer to zooplankton consumers. / Thesis / Master of Science (MSc)

The rock art that is found in the region of Reindeer Lake, Saskatchewan is part of a larger category of rock art known as the Shield Rock Art Tradition. At present, there are more than 400 known and recorded rock art sites throughout the Canadian Shield region. These sites are found over an extensive geographical area and can be found from south-western Quebec across the Shield westward, up to north-western Saskatchewan. The majority of these rock art sites are comprised of imagery that has been painted on rock surfaces. The rock art sites at Reindeer Lake, or panels as they are called, depict a variety of symbols and characters that portray humans, animals, anthropomorphs, ceremonies and motifs of a spiritual nature. A variety of explanations have been proposed as to the function and meaning of rock art in general. Among the more accepted explanations are that rock art paintings were created by shamans; that they depict dreams or visions of an individual seeking medicine or participating in a vision quest/puberty rites; that they are a form of hunting magic whereby the author in capturing the animal in a painting assures capture of the animal in life; or that they serve as markers for travellers. Regardless of function and meaning, all of the rock art sites on Reindeer Lake are of immense heritage value and should be regarded as sacred locations. Very little is known about the rock art in the Reindeer Lake regions. Before any significant analyses of their meaning can be conducted, they must first be relocated and properly documented. At present there are only a very small number of publications that document or mention the Reindeer Lake rock art. This thesis surveys the rock art of Reindeer Lake, Saskatchewan. It discusses the general nature of pictographs from the Shield Rock Art Tradition and how the panels at Reindeer Lake fit into the overall scheme, and applies a systematic method to the recording and analysis of pictographs using a contextual approach. Although the primary focus is on recording the painted imagery, the specific context of each panel as well as the surrounding landscape is also considered. Recording these ancient rock art sites using a proper systematic method has ensured that this significant element of Aboriginal culture will endure not only for future research, but also for the benefit of future generations of the local Cree people.

The rock art that is found in the region of Reindeer Lake, Saskatchewan is part of a larger category of rock art known as the Shield Rock Art Tradition. At present, there are more than 400 known and recorded rock art sites throughout the Canadian Shield region. These sites are found over an extensive geographical area and can be found from south-western Quebec across the Shield westward, up to north-western Saskatchewan. The majority of these rock art sites are comprised of imagery that has been painted on rock surfaces. The rock art sites at Reindeer Lake, or panels as they are called, depict a variety of symbols and characters that portray humans, animals, anthropomorphs, ceremonies and motifs of a spiritual nature. A variety of explanations have been proposed as to the function and meaning of rock art in general. Among the more accepted explanations are that rock art paintings were created by shamans; that they depict dreams or visions of an individual seeking medicine or participating in a vision quest/puberty rites; that they are a form of hunting magic whereby the author in capturing the animal in a painting assures capture of the animal in life; or that they serve as markers for travellers. Regardless of function and meaning, all of the rock art sites on Reindeer Lake are of immense heritage value and should be regarded as sacred locations. Very little is known about the rock art in the Reindeer Lake regions. Before any significant analyses of their meaning can be conducted, they must first be relocated and properly documented. At present there are only a very small number of publications that document or mention the Reindeer Lake rock art. This thesis surveys the rock art of Reindeer Lake, Saskatchewan. It discusses the general nature of pictographs from the Shield Rock Art Tradition and how the panels at Reindeer Lake fit into the overall scheme, and applies a systematic method to the recording and analysis of pictographs using a contextual approach. Although the primary focus is on recording the painted imagery, the specific context of each panel as well as the surrounding landscape is also considered. Recording these ancient rock art sites using a proper systematic method has ensured that this significant element of Aboriginal culture will endure not only for future research, but also for the benefit of future generations of the local Cree people.