Zugl.: Port-au-Prince, Internat. Faith Theol. Seminary Univ. College, Diss., 2008

The aim of this study was to investigate spatial changes in the trophic and energy pathways of the benthic community in the shallow shelf waters of the sub-Antarctic Prince Edward Islands (PEI). A combination of stable isotope and fatty acid analyses were used to provide a time-integrated view of the assimilated feeding history of selected components of the PEI benthic community. This study forms part of the larger project entitled “Variability in the Southern Ocean ecosystems” and is a contribution to the South African National Antarctic Programme (SANAP). During austral autumn 2009, benthic specimens were collected from 10 stations (from depths of 70 to 295 m) in different regions around the PEI: inter-island shelf (upstream, between and downstream of the islands) and nearshore. Historical data were combined with new data collected during 2009 to assess the long-term trends in the feeding ecology of the benthos in the region of the islands. The stable isotope and fatty acid signatures of the benthic suspension- and deposit-feeding organisms generated during this study suggested that these two communities incorporated both phytoplankton and kelp in their diets. Stable isotope, and to a lesser extent fatty acid signatures, indicated that kelp contributed more to the diets of those organisms in close proximity to the kelp beds (nearshore stations) than those from the inter-island region. Overall, however, pelagic phytoplankton was the dominant food source in the diets of all organisms, even for those living near the kelp beds. Notable exceptions were the sponges and bryozoans, in which kelp and phytoplankton contributed similar proportions to their diets, most likely resulting from a size restricted feeding mode. There were, therefore, no distinct spatial differences in the importance of the various food sources. However, fatty acid compositional data indicated increased food quality between and within the lee of the islands compared to upstream. The organisms collected upstream of the PEI had substantially lower quantities of total fatty acids (TFAs) than organisms of the same species collected from nearshore, open shelf or downstream stations. The increased food quality between and within the lee of the islands was likely a result of the “island mass effect”, which reflects increased phytoplankton concentrations at the PEI. The fatty acid profiles of hyperbenthic shrimp Nauticaris marionis, a key species in the PEI ecosystem, revealed no distinct ontogenetic or spatial patterns. This result is in contrast to the stable isotope analyses, which detected both spatial and ontogenetic differences in the diet of the shrimp. Nearshore shrimp were more ₁₃C-enriched than those from the inter-island region, suggesting increased kelp entering the food web within these regions. In addition, the shrimps demonstrated enrichment in δ₁₃C and δ₁₅N signatures with an increase in size, resulting in a relatively distinct separation of size classes, thus reflecting niche separation through their diets. The fatty acid profiles revealed that the shrimp all contained large proportions of polyunsaturated fatty acids (PUFAs) and essential fatty acids (EFAs), indicating that the quality of food consumed was similar among size class and region despite the niche separation and variation in carbon sources utilised. In addition, diatom and dinoflagellate fatty acids (20:5ω3 and 22:6ω3, respectively) occurred in the highest proportions in N. marionis, highlighting the importance of phytoplankton (indirectly) in their diet. These results represent strong evidence that phytoplankton is an importance food source in the PEI ecosystem. The temporal investigation of isotope signatures in the benthos at the PEI indicated that N. marionis demonstrated an overall depletion in δ₁₃C signatures over the period of 1984 to 2009 (nearshore: -2.55 ‰, inter-island: -2.32 ‰). Overall, the benthic community showed similar depletions in δ13C signatures (from -1.96 to -4.70 ‰), suggesting that shifts have occurred in the carbon signatures at the base of the food web. The depletion in δ₁₃C signatures of the benthos at the PEI most likely reflects increased contributions of smaller slow growing phytoplankton cells (more depleted signatures than large fast growing cells) in the diets of these organisms over time. These diet shifts, in turn, suggest a decrease in productivity has occurred at the islands, likely due to a decreased frequency and intensity of the “island mass effect”. Decreased phytoplankton productivity at the PEI likely results from the southward shift in the average position of the sub-Antarctic Front (SAF), most likely in response to climate change, which in turn promotes flow-through conditions rather than retention at the PEI.

No description available.

Dissertation (PhD)--University of Stellenbosch, 2006. / ENGLISH ABSTRACT: The spatial distribution of animals and plants at different scales is a central theme in ecology. Knowledge of biodiversity distribution is essential, especially with the current threat of climate change and invasion by alien species. Since the impact of climate change and alien species will be, and has already been pronounced in polar regions, information on the current spatial distributions of biota in these regions is critical to predict the consequences of climate change and alien species on the future survival, distribution and abundance of indigenous biota. This study was conducted on the sub- Antarctic Prince Edward Islands (consisting of Marion Island and Prince Edward Island), which have experienced rapid climate changes over the past 50 years. Additionally, a number of alien plant, vertebrate and invertebrate (also microarthropod) species have been introduced to these islands. Since microarthropods (mites and springtails) play an essential role in decomposition and mineralization of plant material on the islands, the loss of microarthropods from decomposer communities might have disastrous results for ecosystem processes. Therefore it is essential to know the current distributions of microarthropods in order to predict future distributions patterns in reaction to climate change and invasive species. In this study, the spatial distribution of mites and springtails inhabiting the cushion plant Azorella selago Hook, were examined at different scales of observation. Firstly, the microarthropod community was examined at a fine scale. The relationship between microarthropod species richness and abundance and plant size, isolation, within-plant variability, grass cover and microclimate variables were investigated. Thereafter, the spatial variability of microarthropod abundances was examined within stands of plants, with statistical methods using varying degrees of locational information to determine if microarthropod abundance is random, regular or aggregated at this scale. Further, the spatial variability of microarthropod communities in A. selago at different altitudes and on different sides of Marion Island, i.e. island-wide scale, was examined. The last scale of observation was the island-wide scale, in which microarthropod assemblages were compared between Marion Island and Prince Edward Island, as well as in different plant species. Microarthropods showed spatial heterogeneity within A. selago plants (higher abundances in eastern and southern sides of plants), island-wide (lower springtail abundance on the eastern side of the island and at high altitudes) and between islands (more alien species on Marion Island). In contrast, microarthropod abundance was not spatially heterogeneous within a stand of plants, i.e. mostly randomly distributed. The possible mechanisms responsible for these patterns differ between scales, and range from temperature and nutrient availability at the within plant and island wide scale to alien species between islands. Climate change is likely to alter these distribution patterns of microarthropods, either directly (unfavourable climate for indigenous species growth, development and dispersal) or indirectly (favouring alien microarthropod species; increase in grass cover on A. selago plants may alter community structure). The information presented here, is essential for predicting the possible impacts of climate change on microarthropods in fellfield ecosystems on sub-Antarctic islands. / AFRIKAANSE OPSOMMING: Die ruimtelike verspreiding van diere en plante op verskillende skale is ‘n sentrale tema in ekologie. Kennis van die verspreiding van biodiversiteit is belangrik, veral met die huidige bedreiging van klimaatsverandering en indringerspesies. Omdat die impak van klimaatsverandering en indringerspesies in die poolstreke alreeds duidelik is en nog meer so sal word, is inligting oor die huidige ruimtelike verspreiding van biota in hierdie streke noodsaaklik. Hierdie studie is op die sub-Antarktiese Prins Edward-eilande (bestaande uit Marion Eiland en Prins Edward Eiland) uitgevoer, waar die klimaat vinnig verander het oor die afeglope 50 jaar. Bykomend is ‘n aantal indringer plant, vertebraat en invertebraat (ook mikroartropood) spesies op die eilande ingebring. Omdat mikroartropoda (myte en springsterte) ‘n baie belangrike rol in ontbinding en mineralisering van plantmateriaal op hierdie eilande speel, sal die verlies van mikroartropoda uit die ontbindingsgemeenskap rampspoedige gevolge vir die prosesse in die ekosisteem hê. Kennis van die huidige verpreiding van mikroartropoda is dus noodsaaklik om die toekomstige verspreidingspatrone, asook oorlewing en volopheid van inheemse spesies in reaksie op klimaatsveranding en indringerspesies, te voorspel. In hierdie studie is die ruimtelike verspreiding van myte en springsterte wat in die kussingplant Azorella selago Hook voorkom, op verskillende ruimtelike skale ondersoek. Eerstens is die mikroartropood gemeenskap op ‘n klein skaal ondersoek. Die verwantskap tussen mikroartropood spesies rykheid en volopheid en plantgrootte, isolasie, binne-plant variasie, gras bedekking en mikroklimaat faktore is ondersoek. Daarna is die ruimtelike variasie van mikroartropood volopheid binne in ‘n plantstand ondersoek deur gebruik te maak van metodes wat verskillende grade van ligging data gebruik. Dit is gedoen om uit te vind of mikroartropood volopheid lukraak, reëlmatig of versameld verspreid is. Verder is die ruimtelike verspreiding van mikroartropood gemeenskappe in A. selago op verskillende hoogtes bo seespieël en op verskillende kante van Marion Eiland ondersoek. Laastens is die mikroartropood gemeenskap op Marion Eiland en Prins Edward Eiland, asook die gemeenskap in verskillende plant spesies vergelyk. Mikroartropoda is ruimtelik heterogeen verspreid binne-in A. selago (meer individue in die oostelike en suidelike kante van plante), asook regoor Marion Eiland (minder springstert individue aan die ooste kant van die eiland asook minder op hoë hoogtes bo seespieël) en tussen eilande (meer indringerspesies op Marion Eiland). In teenstelling hiermee is mikroartropood volopheid ruimtelik homogeen oor ‘n plantstand, dus meestal lukraak verspreid. Die meganismes wat moontlik vir hierdie patrone verantwoordelik is wissel van temperatuur en voedselbeskikbaarheid op die binne-plant en oor die eiland skaal tot indringerspesies op die tussen-eiland skaal. Klimaatsverandering mag waarskynlik mikroartropood verspreidingspatrone direk (ongunstige klimaat vir inheemse spesies se groei, ontwikkeling en verspreiding), of indirek verander (indringer spesies word begunstig; toename in grasbedekking bo-op A. selago mag die gemeenskapstruktuur van mikroartropoda verander). Hierdie inligting is belangrik vir die voorspelling van die moontlike impak van klimaatsverandering op mikroartropoda in klipveld ekosisteme op sub-Antarktiese eilande.

L'aquaculture de bivalves peut influencer les écosystèmes marins côtiers en augmentant le dépôt de matériel organique, qui, alternativement, peut avoir des effets directs et indirects multiples sur la communauté benthique environnante. Cette recherche évalue l'influence de l'aquaculture de moules sur la macrofaune épibenthique à l'île du Prince-Edouard, Canada. L'abondance des macroinvertébrés et des poissons benthiques (> 2 centimètres) a été évalué par des comptes visuels à l'aide du scaphandre autonome à 4 fermes d'aquaculture de moules ainsi qu'à des sites témoins à différentes distances des fermes (50, 100, 500 et 2000 m) au cours des mois de juin, août et novembre 2005. Les assemblages benthiques ont été dominés par des étoiles de mer (Asterias sp. ; 79%), suivis de crabes {Cancer irroratus ; 8% et Neopanope sayi ; 6%), de lunacies (Lunatia héros ; 2%), de plies rouges (Pleuronectes americanus ; 2%), de homards (Homarus americanus ; 1%) et de bernard-l'hermite (Pagarus ;1%). Le nombre d'espèces et l'indice d'équitabilité ont différé selon les fermes et les distances témoins mais aucune tendance ne pouvait suggérer une influence négative résultant de l'aquaculture de moules. Bien qu'il y ait eu de grandes variabilités parmi les emplacements et les dates d'échantillonnage, l'aquaculture de moules a eu un effet positif significatif sur l'abondance totale d'organismes. En effet, l'abondance était généralement plus grande dans les fermes comparativement aux distances témoins. Ces accroissements de l'abondance ont été principalement associés au plus grand nombre d'étoiles de mer et de crabes de roche (C. irroratus). Les augmentations de macrofaune épibenthique ont semblé être en grande partie limitées à la proximité immédiate de la ferme de moules, c'est à dire moins de 50m. Cette tendance reflète probablement la plus grande abondance de ressources alimentaires ainsi que la création d'habitats plus hétérogènes favorables à une plus grande biomasse d'invertébrés et de poissons. Ces constatations indiquent une influence positive de l'aquaculture de moules et les méthodes d'échantillonnage devraient être employées lors d'une évaluation plus complète de l'influence des sites d'aquaculture.

No description available.

No description available.

Thesis (M.A.)--Saint Mary's University, 1997. / Includes bibliographical references.

This thesis examines the consequences and implications of the premature deaths of royal heirs in seventeenth-century Britain. In just four generations between 1603 and 1700 the Stuart dynasty suffered the loss of over twenty-five legitimate offspring before their twenty-first year. Several of these deaths had significant political repercussions, threatening both the continuity of the royal line and consequently the security of the nation. The cultural memory of these lost heirs continued decades and even centuries later. My work seeks to establish the historical significance of their long-lasting appeal by assessing their princely representation in life and analysing its development after death. This study is firmly located within visual culture. However, definitions and classifications of the “visual” are necessarily broad. The emphasis is upon the consideration of seventeenth-century British art as part of a wider cultural process. The opening chapter addresses an apparently obvious, though somewhat neglected, issue - the critical importance of royal heirs. Through examination of the imagery and ceremonial attached to Stuart childbearing and christenings, it asserts the real symbolic significance of princely progeny. Chapter Two develops the study of youthful princely representation. It assesses the portrayal of Stuart heirs as they matured and seeks to identify the principal characteristics. Specifically, it is argued that, from a young age, the projection of Protestantism and martial aptitude was crucial to the formation of their personae. Chapter Three analyses how deceased Stuart heirs were commemorated in the months and years immediately after their deaths. It is contended that the enduring memory of these princes was the result, not of official commemoration, but of the large-scale public response to their deaths. The loss of an heir not only threatened the future of the dynasty but also the stability of the realm. The fourth chapter explores how, through visual and cultural propaganda, the surviving Stuarts attempted to re-group and to assuage social and political anxieties. Chapters Five and Six assess the long-term legacy of these princes in the decades and centuries after their deaths, as well as the political circumstances which gave rise to their enduring memory. These concluding chapters reveal the extent to which memories of deceased Stuart princes lingered, asserting that their representations were often employed for negotiation of the issues and anxieties of later ages. Throughout, my work seeks to establish the importance of these lost heirs and protectors of the Stuart Protestant line. I have endeavoured to retrieve the reputations of princes who came to represent potent symbols of both promise and loss.

"Race" has been used to identify difference among people of different origins. In early twentieth century Canada, a British ideal for civilization dominated and it was into this archetype that new immigrants were thrust. The remarkable progress of this society, heralded by western expansion, can be seen in the Grand Trunk Pacific Railway. Prince Rupert was created as the western terminus of the GTPR and was designed to fulfil the needs of a rapidly expanding Canadian frontier. Prince Rupert was a wholly planned community and firmly embedded in the dominant mores and norms of a British Canada. Prince Rupert, however, was not settled solely by people of British descent. Many continental Europeans, "Asians", and Native persons contributed to the emergence of this new city. "Race" was a common tool to differentiate peoples and define their experience of one another. The dominant British discourse excluded many of the new settlers. Interestingly, what was meant by "White" should not be conflated with British, because the boundary of "white" shifted to encompass continental Europeans if threatened by and obviously non-"white" other. Similarly, other groups s hould not be considered homogenous and treated as having had a shared common experience in Canada. Exploring how these diverse peoples co-existed in Prince Rupert means shifting the focus away from individual experiences and instead putting the emphasis on the process of racialization. Simply put, racialisation is the act of racialising people -- determining who they are based on race as a system of classifying human difference. It is a process because it involves the transmission of ideas over time and in a specific place; engaging people on many different fronts. This thesis will utilise the idea of "sites", ephemeral moments, and places -- real or perceived -- where exchanges took place regarding ideas concerning race. These sites are physical, spatial, economic, cultural, social and ideological. How the process of racialisation developed over time will be demonstrated by the use of sites in Prince Rupert British Columbia. / Graduate