Thesis (M. Sc.)--University of Canterbury, 2007. / Typescript (photocopy). "August 2007." Includes bibliographical references (p. 119-127). Also available via the World Wide Web.

Thesis. 1978. Ph.D.--Massachusetts Institute of Technology. Dept. of Earth and Planetary Science. / Microfiche copy available in Archives and Science. / Vita. / Includes bibliographies. / by Robert Sherman Detrick, Jr. / Ph.D.

The need for a broader geographical and functional perspective in managing natural resources of the Belize barrier reef system was examined. The small country of Belize in Central America is struggling to increase its economic development and growth. It has an excellent natural resource base, the most dramatic component being the extensive barrier reef system just offshore. The research identified key economic and environmental issues relative to Belize’s reef complex, and analyzed resource management policies and actions taken to date. Development and conservation needs suggest a multiple use strategy aimed at economic and environmental sustainability. Due to areal extent and ecological complexity, the present reactive, small-scale and piecemeal approach is not adequate to realize sustainable utilization of the area’s resources. This research shows the need for a broad spatial and interdisciplinary “coastal zone" perspective, leading to a comprehensive and integrated strategy upon which to base resource planning and management. A strategy for the reef system must be accomplished within the broader context of a national resource management strategy, integrating concerns of economic development and environmental protection. As a component of this national policy, the proposed strategy for the barrier reef system is based on principles of multiple use of resources, coastal zone scope, and sustainability. The research supports a reef system-wide protected area, using a biosphere reserve framework and a customized model planning process to implement the strategy. / Master of Science

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Thesis (MTech (Oceanography))--Cape Peninsula University of Technology, 2010 / Coral reefs are in a worldwide state of crisis due to overexploitation. One of the factors contributing to the over exploitation is the marine ornamental industry. This industry utilises a diversity of organisms, comprising approximately 1470 species of fish and more than 300 species of invertebrates. Between April and December 2007, five of the 18 companies who had import permits for South Africa, imported a total of 359 different ornamental species, 252 of these were fish species while the remaining 107 species were invertebrates. During these nine months a total of 32 005 individual organisms were imported into South Africa by the five companies. There were two groups of fish that represented the highest import volumes. These were Amphiprion spp. and Pomacentradae spp., as well as the Gobidae spp. These groups represented 38% and 19% respectively of the total number of fish imported" Aquaculture has the potential to substantially reduce the harvesting pressure on coral reef organisms globally. A small-scale multi-species mariculture system was designed and constructed for benthic egg-laying species of fish (brood stock), corals, and ornamental algae. The system was designed to be low cost and easy to operate. The total capital costs for the system was R15 680.70. In order to estimate the potential yield of an aquaculture facility it is important to know the growth rate of the proposed species under pilot conditions. The use of artificial lighting regimes in aquaculture comes at a financial cost. It is for this reason that it is important to know what lighting scenario yields the highest growth rate of corals. The effects of photoperiod were tested on Sinularia sp. of coral. Two photoperiods were tested, namely: Groups (8:16 h Iight:dark cycle) and Group12 (12:12 h light:dark cycle). No significant difference in weight was found between Group8 and Group12 (p = 0.975). There was however a significant increase (p = 0.002) in Surface-area Pixel Value (SPV) for Groups (1996.73 millipixels pixel-1 day -1) compared to Group12 (983.73 millipixels pixel-1 day -1). The use of a 8:16 h lightdark cycle can thus yield coral of a larger size but not necessarily a higher mass.

Mesophotic reefs represent biodiverse ecosystems that may act as a refuge for depth-generalist coral species threatened in shallow habitats. Despite the importance of coral-algal symbioses, few studies focus on mesophotic zooxanthellae assemblages and their influence on connectivity. This study compared zooxanthellae in Montastraea cavernosa at shallow and mesophotic depths at Flower Garden Banks National Marine Sanctuary and McGrail Bank. Mesophotic corals contained more zooxanthellae and more chlorophyll a and c2 per unit area coral. Increased zooxanthellae within mesophotic corals may represent an adaptive strategy to optimize light capture in low-light environments. Genetic profiles for zooxanthellae assemblages from shallow and mesophotic corals showed similar diversity across banks and between depths. The dominant sequence making up assemblages was identified as Symbiodinium type C1. Similar assemblage diversity suggests that zooxanthellae assemblages will not limit connectivity potential between shallow and mesophotic corals at these reefs. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection

Thomas Schelling proposed a simple spatial model to illustrate how, even with relatively mild assumptions on each individual's nearest neighbor preferences, an integrated city would likely unravel to a segregated city, even if all individuals prefer integration. Many authors assumed that the segregation which Schelling observed in simulations on very small cities persists for larger, realistic size cities. We describe how different measures can be used to quantify the segregation and unlock its dependence on city size, disparate neighbor comfortability threshold, and population density. We develop highly efficient simulation algorithms and quantify aggregation in large cities based on thousands of trials. In particular, we show that for the values of disparate neighbor comfortability threshold used by Schelling, the striking global aggregation Schelling observed is strictly a small city phenomenon. Along the way we prove that in the Schelling model, in the process of evolution, the total perimeter of the interface between the different agents always decreases, which provides a useful analytical tool to study the evolution. At the isolated reef Kingman, it was recently discovered that apex predators constitute 85% of the total fish biomass. This is in sharp contrast to most reefs, where the prey biomass substantially dominates the total fish biomass. The recent study at the two pristine reefs, Kingman and Palmyra also indicates that the predator:prey fish biomass ratio is an increasing function of reef cover. Based on these field observations, we model the fish biomass structure at a pristine coral reef. We introduce a new refuge based mechanism for predator-prey interaction with an explicit dependence on refuge size. Our refuge based model does not assume mass action interaction between predators and prey and may provide a new mechanism in ecology to produce inverted biomass pyramids. Our model yields both the inverted biomass pyramid and the increasing dependence of the predator:prey biomass ratio on reef cover. We add various forms of fishing to our model, and show that sufficiently high fishing pressure with quite general types of fishing transforms the inverted biomass pyramid to be bottom heavy.

Doctorat en Sciences / info:eu-repo/semantics/nonPublished

Thesis: Ph. D., Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Department of Civil and Environmental Engineering; and the Woods Hole Oceanographic Institution), 2015. / Cataloged from PDF version of thesis. / Includes bibliographical references. / To understand how waves and sea level shape sandy shoreline profiles, I use existing energetics-based equations of cross-shore sediment flux to describe shoreface evolution and equilibrium profiles, utilizing linear Airy wave theory instead of shallow-water wave assumptions. By calculating a depth-dependent characteristic diffusivity timescale, I develop a morphodynamic depth of shoreface closure for a given time envelope, with depth increasing as temporal scale increases. To assess which wave events are most important in shaping the shoreface in terms of occurrence and severity, I calculate the characteristic effective wave conditions for both cross-shore and alongshore shoreline evolution. Extreme events are formative in the cross-shore shoreface evolution, while alongshore shoreline evolution scales linearly with the mean wave climate. Bimodal distributions of weighted wave heights are indicative of a site impacted more frequently by tropical storms rather than extra-tropical storms. To understand how offshore wave climate and underlying geometry of a carbonate reef platform shapes evolution of atolls, I simulate the hydrodynamics of a simplified reef flat, using XBeach, a two-dimensional model of infragravity wave propagation. The reef flat self-organizes to a specific width and water depth depending on the offshore wave climate and characteristics of the available sediment. Formation of a sub-aerial landmass, like a motu, can be initiated by a change in offshore wave climate (like a storm), which can create a nucleation site from mobilization and deposition of coarse sediment on the reef flat. Once a motu is present, the shoreline should prograde until reaching a critical reef-flat width. Our conceptual model of reef-flat evolution and motu formation is governed by understanding the hydrodynamics of the system and subsequent response of sediment transport. / by Alejandra C. Ortiz. / Ph. D.

Dimethylsulphoniopropionate (DMSP) and dimethylsulphoxide (DMSO) (collectively DMSP/O) are produced by marine algae, including symbiotic algae within corals. These sulphur compounds are important not only in sulphur cycle dynamics but also in potentially mediating atmospheric conditions, alleviating the effects of climate change and contributing to reef health. Most research has focused on the production of DMSP and its major degradation product, the climatically active gas, dimethylsulphide (DMS) by Acropora corals in the Great Barrier Reef. However, mechanisms for the production and release of DMSP/O by different reef taxa is poorly understood. Recently the importance of mesophotic reefs as refugia for shallow water corals has been postulated, however their role in the marine sulphur cycle is unknown. This research aimed to improve our understanding of the contemporary and climate change induced seawater and tissue production of DMSP/O in a range of reef environments and taxa. This was achieved through a combination of laboratory and field - based studies, using modern and established techniques. An effect of both elevated temperature and OA on increased tissue and seawater concentrations of DMSP/O production is reported in field and laboratory studies. Contrasting effects of benthic cover on tissue DMSP/O distributions and seawater DMSP are also noted. The importance of the physical and hydrodynamic environment on biogeochemical connectivity both within a reef and between neighbouring reefs is also focussed on. Crucially, however, the novel tissue and seawater data from mesophotic sites suggests that deeper reefs could affect the biogeochemistry of their shallow water counterparts. The key finding from this work is that climate change will result in increased seawater DMSP concentrations via two mechanisms; through the increase of cellular production of DMSP/O in all reef taxa, and by increasing the biomass of prolific DMSP producers as reefs transition to a fleshy/macroalgal assemblage. Whilst this could potentially mediate the effects of climate change, it will probably also worsen overall reef health, lead to a restructuring of reef communities from the microbial level upwards and will have possibly permanent and deleterious effects on overall ecosystem function.