Determining the relative roles of top-down vs. bottom-up forces in controlling the structure of ecological communities is of primary importance because anthropogenic nutrient loading, overharvesting of consumers, and potential interactions of these forces are pervasively changing ecosystems throughout the world. Here I use both field experimentation and meta-analyses to investigate the role of predators in controlling community composition, the relative roles of herbivores vs. nutrient enrichment in controlling the abundance of benthic primary producers, and the influence of herbivore diversity on the community structure of coral reefs. On a coral reef in the Florida Keys, I showed that release from predation by large fishes and invertebrates via exclusion cages allowed population increases in the gorgonian-eating gastropod Cyphoma gibbosum which increased predation rates on gorgonian corals. To directly address the relative roles of top-down and bottom-up forces in controlling primary producers in benthic marine habitats, I used factorial meta-analysis of 54 field experiments that orthogonally manipulated herbivore pressure and nutrient loading to quantify the effects of consumers and nutrient enrichment on community structure. The relative effects of herbivores vs. nutrient enrichment were context dependant, varying with latitude, the type of primary producer, and the nutrient status of the system. To address the influence of herbivore diversity on the community structure of Caribbean coral reefs, I used manipulative field experiments over two years to show that a Caribbean reef changes dramatically as a function of herbivorous fish diversity. The effects of herbivore diversity on community structure were strong in both years of the experiment due to different diet preferences among herbivores. Higher herbivore diversity suppressed macroalgal abundance, increased abundance of crustose coralline algae, reduced coral mortality, and increased coral growth when compared to treatments with lower herbivore diversity. Complementary feeding by different fishes drove these patterns because macroalgae were unable to effectively deter feeding by fishes with different attack strategies. Thus, herbivore diversity appears to play an important role in the healthy function of coral reef ecosystems via complementary feeding of different herbivore species.

The main purpose of this research was to analyze the distribution and accumulation of metals in sediment cores of Gao-ping Canyon nearby areas. Enrichment factor (EF) and Sediment Quality Guidelines (SQGs) were also used to assess the pollution history, sources and extent of heavy metal pollution. The results revealed that copper and cadmium metal concentrations have not been contaminated significantly; while zinc and lead concentrations reached moderate degree of pollution, which exceeded guidelines of Low-SLG in Ontario and ERL in NOAA. The concentration of lead was higher than most found in Taiwan. Although chromium was found mild polluted, but attention should still be paid as those concentrations exceeded the values of Low-SLG¡BSevere-SLG and ERL. Comparing results from cores in Southern and Northern shelves of Gao-ping Canyon, the trend of heavy metal concentrations in Northern shelf rose gradually but had an apparent downward trend in surface mixed layer; while distinct variation with time was observed in Southern shelf.

This study focuses on the relationship between hydrological and nutrient conditions in seawater surrounded by Dongsha Atoll. Dongsha Atoll is located in the northern South China Sea (NSCS), the water properties should be in coherence with the NSCS water masses. However, due to the semi-enclosed topography the water inside Dongsha Atoll is largely affected by local insolation and rainfall. Significant relationships between SiO2 or PO43- and salinity indicate that rainfall could be a major source of these nutrients. Insignificant relationship between N+N and salinity indicates that rainfall and nitrogen fixation both might affect the distribution of N+N. Temporal variations of temperature and chlorophyll a were alike, except for which occurred in July, 2011. It was probably caused by photo inhibition on phytoplankton growth. The inventory of chlorophyll a was positively correlated with both N+N and SiO2 but not with of PO43-, indicating that phytoplankton growth in Dongsha Atoll was mainly affected by N+N and SiO2. Phytoplankton growth maybe limited by N+N but not by SiO2, as the concentration of SiO2 was mostly beyond the limitation concentration for phytoplankton. According to close relationships between chlorophyll a and TSM, POC and PN, the particulate matter maybe mainly derived from biological origins. The inventory of chlorophyll a was positively correlated with both dissolved organic carbon (DOC) and dissolved organic nitrogen (DON), manifesting the importance of biological origins for DOC and DON concentration. The ratios of DOC/DON, DON/DOP and DOC/DOP within the atoll were in ranges of 7.34-303 (mean: 30.4), 3.00-142 (mean: 22.7) and 104-2546 (mean: 421), respectively. The ratios are higher than those values in NSCS and East China Sea, implying the excretion of carbon-enriched DOM by phytoplankton. The concentration of chlorophyll a, DOC and POC were higher in the Small Lagoon than in the Atoll Lagoon, implying a relatively high productivity in the Small Lagoon. The fluxes of carbonate in the atoll was more than 30 times of the flux in the NSCS, due to its unique characteristics in the coral reef habitat. The organic matter of settling particulates was mainly derived from biological sources. The metal of enrichment factor of settling particulates reveals that Fe and Al are mainly derived from crustal sources, while Cu, Zn and Pb are likely influenced by anthropogenic sources.

Optimization methods have been developed and refined throughout many scientific fields of study. This work utilizes one such developed technique of optimization called simulated annealing to produce optimal operation parameters for a 15x15 fuel assembly to be used in an operating nuclear power reactor. The two main cases of optimization are: one that finds the optimal 235U enrichment layout of the fuel pins in the assembly and another that finds both the optimal 235U enrichments where gadolinium burnable absorber pins are also inserted. Both of these optimizations can be performed by coupling Adaptive Simulated Annealing to TransLAT which successfully searches the optimization space for a fuel assembly layout that produces the minimized pin power peaking factor. Within given time constraints this package produces optimal layouts within a given set of assumptions and constraints. Each layout is forced to maintain the fuel assembly average 235U enrichment as a constraint. Reductions in peaking factors that are produced through this method are on the order of 2% to 3% when compared to the baseline results. As with any simulated annealing approach, families of optimal layouts are produced that can be used at the engineer’s discretion.

The research, first, is to investigate the characteristics and heavy metal content of sediments and bottom water in Kaohsiung harbor by sampling. Second, it is to analyze the correlation of the sediments data by statistics analysis method. According to the correlation ratio, we can try to explain the distribution of heavy metals in the sediments and the water. Finally, it is to analyze the sediments data in Kaohsiung harbor from the year of 2001 to 2004 by principle compounds analysis of multivariate statistical analysis; the purpose is to find out the main reason that causes the variation of the sediments in the harbor area. The result of the sediments analysis shows that, the pollutants in Jen-Gen River, Love River and Canon River deposit in the outlet area and lead to significant difference in spatial distribution of sediments characteristics and heavy metals content in Kaohsiung harbor. The enrichment factors of heavy metals in sediments indicate that, there are enrichments for Hg (EF = 7.9 - 115), Pb (EF = 2.1 ¡V 11.7), Cd (EF = 2.4 ¡V 29.8), and Zn (EF = 1.9 ¡V 19.8) in the harbor area. And there are differences of height in the spatial distribution. The Cr enrichment (EF = 1.1 - 10.9) in the harbor exists only in the nearby area of the river outlet, especially in station KH-10 (EF = 10.9) nearby Jen-Gen River area. There is Cu enrichment in the harbor area (EF = 1.2 - 9.0) except the First and Second Harbor Entrance stations. The correlate tests of the sediments characteristics to the heavy metal concentration show that, volatile solid materials, grease and heavy metals reach significant correlated level (P<0.05); but it is irrelevant between clay and heavy metals (P>0.05). Therefore, the main controlling factor that influences the distribution of heavy metals is not the sedimentary particulates distribution but the organic characteristics. Ni distribution of bottom water in Kaohsiung harbor area, it has higher concentration from station KH-01 to KH-10 (0.4 -1.0£gg/L); and, among them, it has the highest concentration and high variation at station KH-06 (1.0 ¡Ó 1.0£gg/L). The distribution of Cu average concentration is between 1.2 - 2.9£gg/L. There is no absolutely tendency, neither is significant difference. The result of the research on Ni, SiO2 and PO4 correlated analysis is different from the result of Yeats and Campbell (1983), Chung (1995) and Huang (2002). I conjecture that the course could be the different geographic environment (Yeats and Campbell in Atlantic, Chung and Huang in the southwestern waters of Taiwan, the research in Kaohsiung harbor area). The result of sediments principle compounds analysis shows that, the sediment constituents in 2001 and 2002 are high water content, organic and fine-grain organic polluted sediments. The polluted sediments are reduced in 2003 and 2004, and that accords with the time of the harbor area dredges procedures. Therefore, there is causation between them. From PC1 and PC2, we know that Love River (KH-04), Canon River (KH-06) and Jen-Gen River (KH-10) outlet are seriously polluted in the harbor area. The river water that contains the industrial wastewater and municipal wastewater in the upper stream is the most important reason that influences the harbor sediments. The result of the research shows that, the main controlling factor that influences the distribution of heavy metals is the harbor sediment organic characteristics and that could cause the metal ions and organic matter forming into stable organic metals compounds. Its impact to ocean ecosystem is enormous, especially to benthic system. Therefore, I suggest that we should do monitoring analysis on sediment toxicity or toxic organic compounds in order to realize their influences to the ocean ecosystem. And furthermore, we should realize the standing crop and the distribution of the toxic organic compounds so that we can avoid health harming from the accumulation of the ecological food chain returning to human body.

Prymnesium parvum Carter, a haptophyte species capable of forming harmful algal blooms (HABs), has been identified in fresh and brackish water habitats worldwide. In Texas, P. parvum blooms have diminished local community revenues from losses to tourism, fishing, and hatchery production. In this thesis, P. parvum dynamics were studied using in-situ microcosm experiments at Lake Possum Kingdom, Texas during three seasons (fall, winter, spring) in 2004-2005. Specifically, nutrient additions were used to test the hypothesis that increased nutrient levels would not enhance P. parvum's ability to invade phytoplankton communities. In addition to full nutrient additions to levels of f/2 media, other treatments included nutrient additions deficient in either nitrogen (N) or phosphorus (P). Additionally, barley straw extract was tested as a growth inhibitor to prevent P. parvum blooms. Furthermore, P. parvum initial population density was examined to test the hypothesis that increased initial populations could promote an increase in P. parvum population densities. Findings indicated that P. parvum populations in Lake Possum Kingdom would not likely gain a selective advantage over other species when inorganic nutrients (nitrogen and phosphorus) were not limiting. P. parvum did, however, gain an advantage during both N- and P-limited conditions as indicated by toxicity, cell concentrations, and bulk phytoplankton community shifts. Furthermore, P. parvum blooms in Lake Possum Kingdom would likely not be inhibited by barley straw extract application. Initial population densities affected the final population density, but only when initial populations were low. A method to quickly and accurately detect the presence of P. parvum is needed due to P. parvum's potential to cause toxic and lethal blooms. This thesis tested whether P. parvum photopigments are conservative regardless of growth conditions and could be used to quantify the relative abundance of P. parvum in mixed community samples. If biomarker pigments are conservative, then an optimized version of CHEMTAX could be employed as an alternative diagnostic tool to microscopy for enumeration of P. parvum. However, P. parvum pigments in the Texas strain were not conservative throughout the growth cycle and therefore may not be a reliable indicator of cell abundance.

<p>Microarray technology allows measurement of the expression levels of thousand of genes simultaneously. Several gene set analysis (GSA) methods are widely used for extracting useful information from microarrays, for example identifying differentially expressed pathways associated with a particular biological process or disease phenotype. Though GSA methods like Gene Set Enrichment Analysis (GSEA) are widely used for pathway analysis, these methods are solely based on statistics. Such methods can be awkward to use if knowledge of specific pathways involved in particular biological processes are the aim of the study. Here we present a novel method <strong><em>(Knowledge Based Gene Set Analysis: KB-GSA</em></strong>) which integrates knowledge about user-selected pathways that are known to be involved in specific biological processes. The method generates an easy to understand graphical visualization of the changes in expression of the genes, complemented with some common statistics about the pathway of particular interest.</p>

<p>Environmental enrichment (EE) is used to improve the wellbeing of animals in human care. One way of testing what resources an animal prefers to have access to, is to make it pay a price. The price is in the form of time or energy spent to get access to the resource. When measuring the motivation of animals it is useful to compare the resource which is to be evaluated to a resource with a known value. Food is often the comparator. The maximum price paid approach measures the highest price an animal is willing to pay for access to a</p><p>resource. In this study the motivation of a grey seal (Halichoerus grypus) for getting access to artificial kelp and live fish was measured. Food was used as the comparator. A large net cage with a weighted entrance and a nonweighted exit gate was used as the test arena. The seal had to enter it by opening the entrance gate which had increasing weights every day, in 10 steps up to 65 kg. The seal was not willing to pay any price for the live fish. The maximum price paid for the food was 60kg, and for the artificial kelp 10kg, i.e. 17% of the maximum price paid for food. The results suggest that neither</p><p>live fish nor artificial kelp was an attractive EE for this seal. However, the study also shows that spring (reproductive period) is not a good time to test motivation in grey seals.</p>

Thesis (M. Sc.)--University of Hong Kong, 1978. / Carbon copy of typescript.

Coastal communities will be most affected by global climate change and are important to study to understand current and future ecological processes. The current model for global climate change predicts a change in rainfall, which will alter the salinity of coastal systems. Given the presence of eutrophication in many coastal waters, it is important to understand the effects that this increase in nutrients, coupled with changes in salinity, will have on these communities. This study was conducted to understand the effect of salinity increase on the growth and herbivory of the black mangrove, Avicennia germinans, in the presence of increased nutrients. Explicitly, the effects of changing salinity (high, medium, and low) were coupled with fertilizer additions of nitrogen, phosphorus, both, or no fertilizer. Nutrient enrichment differentially affected the growth and herbivory of the plants between salinity zones. The medium salinity zone consistently produced the greatest increases in growth and herbivory. Added nutrients did not have an effect on growth in the low salinity zone. However, added nitrogen increased some growth variables in the medium salinity zone and added phosphorus increased some growth variables in the high salinity zone. Phosphorus also increased herbivory. The results point to diverse processes acting along the salinity gradient. There appears to be differential N- and P-limitation along the gradient. Additionally, the growth differences indicate abiotic and biotic limitations across the salinity gradient, with debilitating salinity acting in the high salinity zone and competition acting in the low salinity zone.