The biogeographical pattern of the brown macroalgal genus Sargassum as well as the phylogeography of selected Sargassum spp. along NW Pacific coast were elucidated using analytical biogeographical and comparative phylogeographical tools. / To investigate the effect of freshwater outflow from Yangtze and Yellow Rivers in eastern China in shaping the genetic population structure of Sargassum spp., a comparative phylogeographic study was conducted on four closely related Sargassum species showing either continuous (Sargassum thunbergii and S. muticum ) or discontinuous (S. hemihyllum and S. fusiforme) distribution patterns along the Chinese coast. The results showed discontinuously distributed species to exhibit more haplotypes (e.g. four in TrnW_I spacer) among their populations than those with continuous distribution (two in TrnW_I spacer) pattern. Little or no population differentiation is revealed in species with a continuous distribution. Their occurrences in the brackish Bohai region may be attributed to the presence of inherited physiochemical traits that allow them to tolerate lower salinity waters in estuaries. The discontinuously distributed species, however, exhibited a deep genetic divergence among populations, as revealed by various genetic markers. There are two main lineages of S. fusiforme based on ITS2 and TrnW_I sequences, but the geographical region associated with this genetic break between the two lineages in eastern and southwestern Japan is different from that of S. hemiphyllum. Analysis of molecular variance (AMOVA) results indicate that the maintenance of the population structure of S. fusiforme appears not to be correlated with the outflow of the two rivers. For S. hemphyllum, reduced salinity as the suspected genetic barrier was investigated directly in the laboratory to elucidate its effect on the growth and survival of S. hemiphyllum var. chinense . Statistically significant difference was observed in the relative growth rate (calculated based on wet weight) of branches cultured under different salinities, with the optimal growth under salinity level of 33 ppt. The lethal limit of vegetative growth was between 0 and 10 ppt. Germlings cultured in 15 ppt attained the highest survivorship. The optimal growth of the germlings occurred at 25 ppt, while the lowest lethal limit was within the range of 0 ppt and 5 ppt. Germlings reared under low salinity were deficient in rhizoid development, making them highly unlikely to grow into large thallus in the natural environment with strong waves. Compared with the optimal and lethal salinity level of S. mutium, the lethal limits of both vegetative branches and germlings of the two species are comparable. The optimal growth of branches of S. muticum occurred under salinity level of 27 ppt, in contrast to the optimal salinity level of S. hemiphyllum at 33 ppt. This could have explained the absence of S. hemiphyllum in brackish water and support the suggestion that river discharge serves as a barrier for the exchange of genetic materials among its populations. (Abstract shortened by UMI.). / Two allopatrically distributed varieties of S. hemiphyllum, v. chinense and v. hemiphyllum, are genetically distinct in terms of their internal transcribed spacer 2 (ITS2) and Rubisco spacer. The genetic break between these two varieties, with v. chinense distributed in southern Chinese coast and v. hemiphyllum in Japan and Korea, is situated in a region that includes Bohai, Yellow Sea and East China Sea, all of which were heavily influenced by the Yangtze and Yellow Rivers in China. An introgression of the mitochondrial (Mt) genome from v. chinense to v. hemiphyllum, possibly mediated by the Kuroshio Current, is evident based on the Mt marker TrnW_I spacer. Hybridization between the two varieties may still be ongoing since the concerted evolution of ITS2 is not yet saturated in the Korean population located geographically in-between the distribution of the two varieties. In contrast, no variation in ITS2 and Rubisco spacer is revealed in S. muticum, including the native Asian populations and introduced populations in Europe and North America. There is a fixed one-nucleotide difference in the TrnW_I spacer, between the population in eastern Japan and all the other populations examined. This finding supports the earlier suggestion that the source of the introduced S. muticum populations is western and central Japan (Seto Inland Sea), where the germlings of S. muticum have been associated with the Pacific oysters previously introduced for farming in Canada, UK and France in earlier years. / Cheang, Chi Chiu. / Advisers: Put O. Ang; Ka-Hou Chu. / Source: Dissertation Abstracts International, Volume: 73-09(E), Section: B. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 221-247). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Thesis (M.S.)--University of North Carolina Wilmington, 2008. / Title from PDF title page (viewed May 27, 2009) Includes bibliographical references (p. 132-135)

Made available in DSpace on 2015-05-14T12:59:30Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 4079723 bytes, checksum: 557a5e2177144da21ce60f2cab677ba0 (MD5) Previous issue date: 2012-02-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Sargassum is a genus of brown seaweeds from the family Sargassaceae and is represented by 150 species. The literature reports the presence of alginates, phlorotanins, coumarins, chromones, quinones, phaeophitins and terpenoids. The metabolites produced by algae of the genus Sargassum show biological activities such as anticoagulant, antioxidant, antipyretic and analgesic. The objective of this study was to present phycochemical study of the species Sargassum vulgare var. nanum E. de Paula. The material was collected on the beach in Coqueirinho, Conde- PB, then was washed and lyophilized. The dried powder (841.19 g) was extracted by maceration with ethanol 96 oG.L, obtaining the crude extract (56.96 g) was dissolved in a solution H2O-MeOH (7:3) and partitioned with ethyl ether, dichloromethane and ethyl acetate. The ether extract (17.04 g) was subjected to silica gel chromatography column eluting with hexane, dichloromethane and ethyl and MeOH pure or in binary mixtures. The combined fractions (75-93) were subjected to chromatography with Sephadex LH-20 eluted with CH2Cl2-MeOH (1:1). The purified fraction Sv-1 was identified as fucosterol, the first reported in this specie. Other fractions (119-121 and 135.1) were subjected preparative thin layer chromatography (PTLC) with AcOEt-Hexane (25:75) and (40:60) to afford mixture -(132)-(R) and (132)-(S)-132-hydroxy-phaeophytin-a encoded as Sv-2 and 151-hydroxy-(151-S)-porphyrin lactone encoded as Sv-3. The R isomer of 132-hydroxy-phaeophytin-a is first reported in the genus and S isomer for the first time in this specie, while the porphyrin lactone is first reported in the family Sargassaceae. Structural elucidations were carried out based on the analysis of their 1H NMR and 13C NMR spectra and and on the basis of literature data. / Sargassum é um gênero de algas pardas da família Sargassaceae representada por 150 espécies. A literatura relata a presença de alginatos, florotaninos, cumarinas, cromonas, quinonas, feofitinas e terpenóides. Os metabólitos produzidos por algas do gênero Sargassum mostram atividades biológicas, tais como: anticoagulantes, antioxidante, antipirético e analgésica. O objetivo deste estudo foi apresentar estudo ficoquímico da espécie Sargassum vulgare var. nanum E. de Paula. O material foi coletado na praia de Coqueirinho, Conde-PB, e depois lavado e liofilizado. O pó seco (841,19 g) foi extraído por maceração com etanol a 96 oG.L, obtendo o extrato etanólico bruto (56,96 g) que foi dissolvido em uma solução de H2O-MeOH (7:3) e particionado com éter etílico, diclorometano e acetato de etila. O extrato etéreo (17,04 g) foi submetido a uma cromatografia em coluna de sílica gel, eluído com hexano, diclorometano e acetato de etila e MeOH puros ou em misturas binárias. As frações reunidas (75-93) foram submetidos a cromatografia em Sephadex LH-20 eluída com CH2Cl2-MeOH (1:1). A fração purificada Sv-1 foi identificado como fucosterol relatada pela primeira vez na espécie. As frações 119-121 e 135.1 foram submetidas cromatografia em camada delgada preparativa (CCDP) em AcOEt-hexano (25:75) e AcOEt-Hex (40:60) das quais foram possivel isolar duas feofitinas Sv-2 e Sv-3 identificada como a mistura de (132)-(R) e (132)-(S)-132-hidroxi-feofitina-a e 151-hidroxi-(151-S)-porfirinolactona a respectivamente. O isômero R da 132-hidroxi-feofitina-a é relatado pela primeira vez no gênero e o isômero S pela primeira vez na espécie, enquanto a porfirinolactona é relatada pela primeira vez na família Sargassarceae. As elucidações estruturais foram realizadas com base na análise de seus espectros de IV, RMN de 1H e 13C uni e bidimensionais e bem como com base em dados da literatura.

Orientador: Meuris Gurgel Carlos da Silva / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-23T11:03:55Z (GMT). No. of bitstreams: 1 Bertagnolli_Caroline_D.pdf: 3477463 bytes, checksum: df8d9fab006a696fa5d027c25e848099 (MD5) Previous issue date: 2013 / Resumo: O cromo é um dos metais pesados que causa mais danos à saúde e ao meio ambiente. É utilizado em uma grande variedade de processos industriais podendo provocar contaminação dos recursos hídricos devido ao descarte de resíduos industriais. Neste trabalho a bioadsorção de cromo total e trivalente pela alga marinha Sargassum filipendula, pelo alginato extraído dessa alga e pelo resíduo da extração, assim como a bioadsorção das espécies de cromo por uma amostra de alginato comercial, foram estudados por meio de ensaios em sistema de batelada e em coluna. Os experimentos envolveram preparo e caracterização dos bioadsorventes, o estudo cinético e de equilíbrio, além de testes em sistema contínuo. Os bioadsorventes foram caracterizados antes e após a bioadsorção por microscopia eletrônica de varredura e o cromo presente no bioadsorvente foi mapeado. As técnicas de espectroscopia na região do infravermelho e espectroscopia de fotoelétrons excitados por raios-X foram utilizadas para compreensão dos mecanismos de ligação cromo+adsorvente e para avaliar o estado de oxidação do cromo adsorvido. O processo de extração do alginato a partir da alga brasileira foi estudado e os produtos da extração caracterizados. Os resultados mostraram capacidades máximas de adsorção obtidas pelo ajuste de Langmuir entre 0,411 e 2,493 mmol/g, com destaque para o resíduo da extração do alginato que se mostrou como uma boa alternativa de bioadsorvente, pois apresentou capacidade de adsorção máxima próxima à da alga e superior à dos alginatos para ambas as espécies de cromo, possibilitando o reaproveitamento de um rejeito do processo e comercialização do alginato extraído. Observou-se a ocorrência de diferentes mecanismos de adsorção simultaneamente, com formação de complexos de ambas as espécies de cromo com grupos sulfônico, amino e carboxila do adsorvente e a contribuição de mecanismos de troca iônica. No estudo da adsorção do cromo hexavalente foi verificada sua redução a cromo trivalente na superfície do adsorvente / Abstract: Chromium is one of the heavy metals that pose the greatest damages to health and to the environment. It is used in a great range of industrial processes, and it might even generate the contamination of water resources due to the disposal of industrial residues. In this study, hexavalent and trivalent chromium biosorption by Sargassum filipendula, alginate extracted from this seaweed, extraction residue and a commercial alginate were studied by means of batch and fixed-bed column. The experiments involved preparation and characterization of biosorbents, kinetic and equilibrium studies. The biosorbents were characterized before and after the biosorption process by scanning electron microscopy and the chromium present in the biosorbent has been mapped. The X-ray photoelectron spectroscopy and infrared spectroscopy have been used to evaluate the chromium oxidation state and the biosorbent group to which the metal is bound after the biosorption process. The process of alginate extraction from Brazilian seaweed has been studied and the extraction products characterized. The results showed the maximum adsorption capacities by Langmuir adjustment between 0.411 and 2.493 mmol/g and the alginate extraction residue as an alternative bioadsorbent. The residue has adsorption capacity near to seaweed and better than the alginates for both chromium species. Different mechanisms were observed for the adsorption of different chromium species as complexation of chromium with sulfonic, amino and carboxyl groups of the adsorbent and ion exchange mechanisms. In the adsorption of hexavalent chromium was verified reduction to trivalent chromium at the surface of the adsorbent / Doutorado / Engenharia de Processos / Doutora em Engenharia Quimica

Orientador: Fosca Pedini Pereira Leite / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-27T14:46:32Z (GMT). No. of bitstreams: 1 Pires_LaryssaFannyGalantini_M.pdf: 1898650 bytes, checksum: e078e521c78de161e961e5f5b734a6e9 (MD5) Previous issue date: 2015 / Resumo: As faces oceânica e continental da Ilha de São Sebastião são distintas em diversos aspectos, mas ambas apresentam a alga parda Sargassum em seus costões. A falta de conhecimento sobre as assembleias de isópodes nestas duas regiões levou ao desenvolvimento do estudo no qual se procurou avaliar a composição, riqueza e diversidade dos isópodes associados ao Sargassum bem como variações espaço-temporais entre e dentro das faces da ilha em dois períodos de amostragem (inverno e verão) entre 2011 e 2013. Para tanto, dez frondes foram amostradas aleatoriamente em cada costão e após a realização de processos laboratoriais, a fauna foi triada e contabilizada. Foram encontrados 9.648 indivíduos, pertencentes a 9 espécies. A riqueza e diversidade foram maiores na face oceânica. Os resultados indicam que a composição de espécies é distinta entre os costões, independente das faces. As diferenças espaço-temporais na composição dos isópodes parecem estar relacionadas aos aspectos biológicos e morfológicos de cada espécie, fatores intrínsecos ás algas, como a epibiose e principalmente a perturbações antrópicas na face continental. A riqueza e diversidade dos isópodes são altas na Ilha de São Sebastião comparada a outras regiões tropicais. Janaira gracilis em geral, dominou em todos os costões e períodos de amostragem. Carpias minutus foi a segunda espécie mais abundante, ocorrendo em altas densidades somente na face oceânica. As demais espécies ocorreram em baixas densidades sendo que Astacilla sawayae e Mesanthura callicera ocorreram somente nos bancos de Sargassum da face oceânica, onde há pouca interferência antrópica. A sensibilidade dos isópodes às alterações ambientais faz deles modelos para a realização de estudos que visem compreender os aspectos ecológicos e biológicos destas espécies, visto que as atividades antrópicas se intensificam a cada dia / Abstract: The oceanic and continental sides of the Island of São Sebastião are being distinct in many ways, but both have the brown alga Sargassum on their shores. The lack of knowledge about the assemblies of isopods in these two regions led to the development of this study that sought to assess the composition and diversity of isopods associated with Sargassum and the spatio-temporal variations between and within both sides of the island in two sampling periods (two winter and summer) between 2011 and 2013. Ten fronds were randomly sampled from each shore and the fauna screened and counted. A total of 9,648 individuals belonging to nine species were found. Richness and diversity values were higher in the oceanic side. Results indicate that the species composition is different between rocky shores independent of the sides. The spatio-temporal differences in the composition of the isopods appear to be related to morphological and biological aspects of each species, intrinsic factors such as epibiosis and anthropogenic disturbances in continental side. Janaira gracilis was generally predominant in all rocky shores and sampling periods, being tolerant to environmental disturbances and anthropogenic interferences. Carpias minutus was the second most abundant species, occurring in high densities only in the ocean side. Other species occurred in low densities, while Astacilla sawayae and Mesanthura callicera, occurred only in Sargassum beds from the oceanic side, where there is still little anthropogenic influence. The sensitivity of isopods to environmental changes make them adequate models for conducting studies aimed at the understanding of ecological and biological aspects of species, whereas anthropogenic activities are intensifying every day / Mestrado / Mestra em Biologia Animal

Yeung, Fai Fai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 212-243). / Abstracts in English and Chinese. / Acknowledgements --- p.i / Abstract (English) --- p.iv / Abstract (Chinese) --- p.x / Contents --- p.xiv / List of Tables --- p.xxii / List of Figures --- p.xxiv / Chapter Chapter 1 --- General Introduction --- p.1 / Chapter I.1 --- General Ideal and Background on Seasonality and Phenology --- p.1 / Chapter I.I.1 --- Seasonality Study of Terrestrial Plant --- p.2 / Chapter I.I.2 --- Study on Seasonality of Marine Algae --- p.3 / Chapter I.2 --- Life History and Seasonality of Sargassum spp --- p.4 / Chapter I.2.1 --- Why Study Sargassum seasonality --- p.5 / Chapter I.2.2 --- Spatial and Temporal Variations in Seasonality of Sargassum spp --- p.6 / Chapter I.2.2.1 --- Differences in seasonality based on locality --- p.7 / Chapter I.2.2.2 --- Interspecific differences in seasonality --- p.7 / Chapter I.2.2.3 --- Intra-specific differences in seasonality --- p.8 / Chapter I.2.3 --- Studies on Seasonality of Sargassum spp. in Hong Kong --- p.9 / Chapter I.3 --- Photosynthesis of Seaweeds --- p.11 / Chapter I.3.1 --- Photosynthesis - Ecophysiological Indicator for Seasonality --- p.11 / Chapter I.3.2 --- Photosynthesis in Different Parts of Seaweeds --- p.13 / Chapter I.3.3 --- New Methodology to Study Photosynthesis --- p.15 / Chapter I.4. --- Scope and Significance of this Thesis Research --- p.16 / Chapter I.4.1 --- General Objectives --- p.17 / Chapter I.4.2 --- Study Organisms --- p.17 / Chapter I.4.2.1 --- Sargassum hemiphyllum (Turner) C Agardh --- p.18 / Chapter I.4.2.1 --- Sargassum siliquastrum (Turner) C Agardh --- p.18 / Chapter I.4.3 --- Study Site --- p.19 / Chapter I.4.3.1 --- Lung Lok Shui (LLS) --- p.19 / Chapter I.4.3.2 --- Lung Yue Tsui (LYT) --- p.19 / Chapter I.4.3.3 --- Lo Fu Ngan (LFN； --- p.20 / Chapter I.4.3.4 --- Lung Ha Wan (LHW) --- p.21 / Chapter I.4.3.5 --- Clear Water Bay (CWB) --- p.21 / Chapter I.4.3.6 --- Tai Tam Wan --- p.21 / Chapter I.4.3.6.1 --- Tai Tam Wan (rock shore) (TTW(rs)) --- p.21 / Chapter I.4.3.6.2 --- Tai Tam Wan (sea school) (TTW (ss)) --- p.21 / Chapter I.5 --- Organization Chart --- p.22 / Chapter Chapter 2 --- Comparative Seasonality of Sargassum siliquastrum and S hemiphyllum in Hong Kong S.A.R --- p.35 / Chapter II.1 --- Introduction --- p.35 / Chapter II.2 --- Materials and Methods --- p.39 / Chapter II.2.1 --- Study Sites --- p.39 / Chapter II.2.2 --- Seasonal Variation in Size and Reproductive Status of Sargassum Plants --- p.39 / Chapter II.2.3 --- "Seasonal Variation in Growth Rates, Population Structures and Densities" --- p.42 / Chapter II.2.4 --- Comparisons between Populations of Sargassum spp --- p.43 / Chapter II.2.5 --- Seasonal Changes in Environmental Parameters --- p.44 / Chapter II.2.6 --- Statistical Analysis --- p.45 / Chapter II.3 --- Results --- p.46 / Chapter II.3.1 --- Seasonality of S. siliquastrum along the Latitudinal Gradient from North to South of Hong Kong --- p.46 / Chapter II.3.1.1 --- Seasonal variation of mean thallus length --- p.46 / Chapter II.3.1.2 --- Seasonality in reproduction --- p.47 / Chapter II. 3.1.3 --- Growth rates --- p.49 / Chapter II.3.1.4 --- Seasonal variations in mean density --- p.50 / Chapter II. 3.1.5 --- Population structure --- p.51 / Chapter II.3.2 --- Seasonality of S. siliquastrum along the Vertical Gradient of Different Depths --- p.56 / Chapter II.3.2.1 --- Seasonal variation of mean thallus length --- p.56 / Chapter II. 3.2.2 --- Seasonality of reproduction --- p.56 / Chapter II.3.2.3 --- Growth rates --- p.57 / Chapter II.3.2.4 --- Seasonal variations in mean density --- p.58 / Chapter II.3.2.5 --- Population Structure --- p.59 / Chapter II.3.3 --- Seasonality of S. hemiphyllum along the Latitudinal Gradient from North to South of Hong Kong --- p.63 / Chapter II. 3.3.1 --- Seasonal variation of mean thallus length --- p.63 / Chapter II. 3.3.2 --- Percentage of reproductive plants --- p.63 / Chapter II.3.3.3 --- Growth rates --- p.64 / Chapter II.3.4 --- Comparison of Seasonality between S siliquastrum and S. hemiphyllum --- p.64 / Chapter II.3.5 --- Comparison of Environmental Parameters among Sites --- p.66 / Chapter II.4 --- Discussion --- p.69 / Chapter II.4.1 --- Inter-specific Comparison on Sargassum phenology --- p.69 / Chapter II.4.2 --- Intra-specific Comparison on Sargassum phenology --- p.73 / Chapter II.4.2.1 --- Comparison along regional scale (> 100kms) geographical range --- p.73 / Chapter II. 4.2.2 --- Comparison along meso-scale (< 100kms) geographical range --- p.77 / Chapter II. 4.2.2.1 --- Comparison along meso-scale latitudinal gradient 一 S. siliquastrum --- p.78 / Chapter II.4.2.2.2 --- Comparison along meso-scale latitudinal gradient - S. hemiphyllum --- p.82 / Chapter II. 4.2.2.3 --- Comparison along vertical depth gradient - S. siliquastrum --- p.87 / Chapter II.5 --- Summary --- p.91 / Chapter Chapter 3 --- Photosynthetic activities of Sargassum siliquastrum and S hemiphyllum in Hong Kong S.A.R --- p.125 / Chapter III.l. --- Introduction --- p.125 / Chapter III.2. --- Materials and Methods --- p.128 / Chapter III.2.1 --- Seasonal Variation in Photosynthetic Activities of Sargassum spp. (Field Monitoring) --- p.128 / Chapter III.2.2 --- Seasonal Variation in Photosynthetic Activities of Sargassum spp. (Laboratory Measurement) --- p.130 / Chapter III.3 --- Results --- p.131 / Chapter III.3.1 --- Initial Preliminary Testing on Sampling Size for PAM Measurement --- p.131 / Chapter III.3.2 --- Seasonal Variations of Effective Quantum Yield (Field Monitoring) --- p.131 / Chapter III. 3.2.1 --- Intra-specific comparison along latitudinal gradient from north to south of Hong Kong 一 S siliquastrum --- p.131 / Chapter III. 3.2.2 --- Intra-specific comparison along latitudinal gradient from north to south of Hong Kong 一 S hemiphyllum --- p.134 / Chapter III.3.2.3 --- Intra-specific comparison along vertical depth gradient - S. siliquastrum --- p.136 / Chapter III.3.3 --- Seasonal Variations of Maximum Quantum Yield (Laboratory Measurement) and Comparative Photosynthesis of Different Parts of Sargassum spp --- p.137 / Chapter III.4 --- Discussion --- p.139 / Chapter III.4.1 --- Seasonal Photosynthetic Performances of S siliquastrum and S. hemiphyllum --- p.139 / Chapter III.4.2 --- Different level of Photosynthesis in Various Parts of Sargassum spp --- p.146 / Chapter III.4.3 --- Comparative Photosynthesis from Different Depths --- p.153 / Chapter III.5. --- Summary --- p.155 / Chapter Chapter 4 --- Transplantation Experiment --- p.172 / Chapter IV.l. --- Introduction --- p.172 / Chapter VI.2. --- Materials and Methods --- p.174 / Chapter IV.2.1 --- Reciprocal Transplantation for S. siliquastrum --- p.174 / Chapter IV.2.2 --- Reciprocal Transplantation for S. hemiphyllum --- p.176 / Chapter VI.3. --- Results --- p.178 / Chapter IV.3.1 --- Reciprocal Transplantation for S. siliquastrum --- p.178 / Chapter IV.3.1.1 --- Mean thallus length --- p.178 / Chapter IV.3.1.2 --- Percentage of reproductive plants --- p.181 / Chapter IV.3.1.3 --- Photosynthetic effective quantum yield --- p.182 / Chapter IV.3.1.4 --- Survivorship --- p.183 / Chapter IV.3.2 --- Reciprocal Transplantation for S. hemiphyllum --- p.184 / Chapter IV.3.2. 1 --- Mean thallus length --- p.184 / Chapter IV.3.2.2 --- Percentage of reproductive plants --- p.185 / Chapter IV.3.2.3 --- Photosynthetic effective quantum yield --- p.186 / Chapter IV.3.2.4 --- Survivorship --- p.187 / Chapter IV.4 --- Discussion --- p.187 / Chapter IV.4.1 --- Transplantation Experiment for S. siliquastrum --- p.188 / Chapter IV.4.2 --- Transplantation Experiment for S. hemiphyllum --- p.192 / Chapter IV.5 --- Summary --- p.196 / Chapter Chapter 5 --- Summary and Conclusion --- p.204 / References --- p.212

Large aggregations of Sargassum, when at sea, provide important habitat for numerous marine species of vertebrates and invertebrates. It is especially important for the young of several species of sea turtles. However, when large aggregations of Sargassum come ashore on beaches frequented by tourist it is often viewed as a nuisance or even a health hazard. It then becomes a burden to beach management and has to be physically removed as quickly as possible. Many Gulf coast beaches suffer from Sargassum accumulation on a regular basis. Timely information on the size and location of the Sargassum habitat is important to developing coastal management plans. Yet, little is known about the spatial and temporal distribution of Sargassum in the Gulf of Mexico. There is no systematic program to assess the distribution of the macroalgae, therefore practical management plans are difficult to execute. In 2008, Gower and King of the Canadian Institute of Ocean Sciences along with Hu of the University of South Florida, using satellite imagery, identified extensive areas of Sargassum in the western Gulf of Mexico. These were not confirmed with ground truthing data. To date ground truthing observations have not been directly compared with the corresponding satellite images to confirm that it was in fact Sargassum, as the satellite images suggested. y building on the information and research methods of Gower and King, current ground truthing data taken from Texas Parks and Wildlife Gulf trawl sampling surveys was analyzed. In addition, shoreline information and imagery was used to substantiate the data derived from current Moderate-resolution Imaging Spectroradiometer (MODIS) Enhanced Floating Algae Index (EFAI) images. As part of the NASA sponsored research project Mapping and Forecasting of Pelagic Sargassum Drift Habitat in the Gulf of Mexico and South Atlantic Bight for Decision Support, NASA satellite MODIS EFAI images provided by Dr. Hu were used to identify and substantiate corresponding floating Sargassum patches in the Gulf of Mexico. Using the most recent advances in technology and NASA satellite remote sensing, knowledge can be obtained that will aid future decision making for addressing Sargassum in the Gulf of Mexico by substantiating the data provided by satellite imagery. Findings from this research may be useful in developing an early warning system that will allow beach managers to respond in a timely manner to Sargassum events.

Made available in DSpace on 2014-06-12T23:02:56Z (GMT). No. of bitstreams: 2 arquivo8273_1.pdf: 1653962 bytes, checksum: 66905f84023590103962c2fdd9b67296 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2007 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / O termo fital foi introduzido por Remane para designar uma outra divisão do ambiente marinho além das categorias tradicionais pelagial e a bentônica, sendo o ambiente fital dominado por macrófitas que têm capacidade de se auto-manter. O presente trabalho pretende contribuir com o conhecimento da malacofauna associada a Sargassum spp e os fatores que estruturam esse ecossistema. Para tanto foram realizadas coletas mensais no Pontal do Cupe, Ipojuca PE (08º 27 31,9 S e 034º 09 00,1 W) sobre um banco multiespecífico de Sargassum C. Agardh. O material foi fixado em formol salino 4% neutralizado com borax, posteriormente se processaram a triagem, identificação dos taxa da malacofauna e medição dos volumes das amostras. Foram calculadas densidade, abundância e freqüências relativas, riqueza de espécies, diversidade específica, equitabilidade e se processaram análises de componentes principais e dendrograma de associação. A malacofauna foi composta por representantes de três diferentes classes de moluscos Gastropoda, Bivalvia e Polyplacophora. Gastropoda foi a classe mais representativa, dominado sobre as demais classes. A densidade total variou ao longo do ano sendo maior entre os meses do período seco. A variação foi resultado da oscilação dos fatores abióticos como temperatura, salinidade que apresentaram maior correlação com alguns taxa. No mesmo período foram encontrados muitos indivíduos em estágio juvenil, podendo o fital de Sargassum spp no Pontal do Cupe servir como berçário ou área de recrutamento para algumas espécies. Foram encontrados novas ocorrências de alguns taxa Cerithiopsis flava, Petalifera sp., Colpodaspis sp. e Doto spp, podendo estar ligado à lacunas de coleta na região ou a bioinvasão por água de lastro sendo necessário acompanhamento da área

Hatchling loggerhead turtles emerge from subsurface nests on the beach at night, crawl down the beach and enter the sea. Recently, increases in a floating algae (Sargassum) has been reported in the mid-Atlantic and the Caribbean, resulting in large algal wrack on Florida beaches. The purpose of my study was to determine if these accumulations acted as a barrier, preventing hatchlings from completing their crawl to the sea. To address this issue I recorded seasonal changes in Sargassum density and directly observed when, and under what circumstances, hatchlings could cross the wrack. There was a significant overlap between when Sargassum accumulation peaked and when the turtles emerged, with the result that hatchling recruitment was significantly reduced (by~22%) during the 2020 nesting season. I conclude that algal accumulations represent a significant threat that may impede the recovery of loggerhead populations, that are currently threatened or endangered worldwide. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2021. / FAU Electronic Theses and Dissertations Collection

A mutualistic symbiosis exists between the alga Sargassum spp. and two shrimp species, L. tenuicornis and L. fucorum. But little is known about how the shrimp locate their host alga. Both visual and chemical cues are potentially available. Visual cues would be presumably restricted at night but chemical cues are potentially available continuously. Additionally, a previous study has looked at both cue variables with results that are mixed. This current research elaborates on the previous study in an attempt to fully understand Sargassum shrimp chemoreception. A y-maze and four-chambered apparatus were used to test if the shrimp were able to detect Sargassum cues, conspecific cues, and Dimethylsulfoniopropionate (DMSP) cues. Neither shrimp species showed a strong directional response to any of the chemical cues, but the Sargassum and DMSP cues did cause more shrimp to exhibit searching behavior. Additionally, several differences in response between male and female shrimp were found for each cue. A weaker dilution of DMSP was tested in an attempt to determine sensitivity of L. fucorum shrimp to the chemical cue. This weaker dilution also caused L. fucorum to exhibit searching behavior, but the sensitivity to the cue was not found and further research is needed to fully answer this question. These results show the shrimp are able to detect chemical cues in their environment and help determine more accurately the role of chemoreception in initiating and maintaining this shrimp/algal association. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2019. / FAU Electronic Theses and Dissertations Collection