Ocean acidification is occurring in response to rapidly increasing concentrations of atmospheric CO2. Shallow-water hydrothermal vent systems have been proposed as natural laboratories for studying the effects of elevated pCO2 on benthic communities. Hydrothermal vents occur at depths of approximately 10m in Tutum Bay, Ambitle Island, Papua New Guinea; these vents are surrounded by a typical-appearing fringing coral-reef community. Groups of live specimens of seven species of reef-dwelling, larger benthic foraminifers, along with segments of calcareous green algae broken from live thalli, were collected from a reef location, placed in small mesh bags, and deployed for five days at six different sites along a gradient of temperature (29.6oC-59.3oC) and pH (5.9-8.1) with distance from a large hydrothermal vent in Tutum Bay. Foraminiferal taxa used in the experiment included Amphisorus hemprichii, a species with Mg-calcite porcelaneous shells, three species of Amphistegina that produce hyaline calcite shells, and three species with hyaline Mg-calcite shells (Heterostegina depressa and two Calcarina spp.). Several specimens of four of the seven foraminiferal species examined survived exposure to elevated temperatures of 59.3oC and low pH of 6.2 for five days, while at least one specimen of each of the seven species survived exposure to 39.9oC and pH 5.9. Examination of shells at 600-1000x magnification using scanning electron microscopy revealed fine-scale dissolution in specimens up to 30m from the vent. Results of this experiment, as well as previously reported observations from the study site, indicate that the calcifying reef-dwelling organisms examined can survive pH extremes that result in dissolution of their shells following death.

A comparison of Elysia (=Tridachia) crispata (Mörch, 1863) from the Virgin Islands with elysiid slugs from the mangrove swamps and canals in the Florida Keys that have previously been identified as E. crispata reveals many differences in habitat, gross and microscopic anatomy, food preferences of juveniles, sources of symbiotic chloroplasts and their localization within the digestive tubules, radular morphology, and nucleic acid sequences of two genes. The differences between the two groups of slugs are such that the Florida Keys animals are considered to represent a new species, Elysia clarki. Elysia clarki feeds on siphonaceous algae, and intracellularly sequesters the chloroplasts, which actively photosynthesize for up to 4 months. We have determined the algal source of the chloroplasts in adult E. clarki from 2 populations in the Florida Keys, using molecular techniques, feeding experiments, and electron microscopy. Our results clearly demonstrate that adult E. clark i sequester chloroplasts from 7 different species of algae, representing two genera, of which 5 were identified; Penicillus lamourouxii, P. capitatus, Halimeda incrassata, H. monile, and Bryopsis pennata. In addition, chloroplasts from more than 1 species of algae are sequestered in the same digestive cell simultaneously. Phylogenetic analysis of rbcL sequences from the order Bryopsidales showed that E. clarki feeding was restricted to calcareous members of the family Udoteaceae and the family Bryopsidaceae. Feeding experiments were conducted, using individuals raised in the laboratory from egg masses laid by E. clarki adults which had been collected from Grassy Key, Florida, USA, and 29 species of macroalgae. For the first 14 d post-metamorphosis, juveniles ate only the thin filamentous coenocytes, Bryopsis plumosa or Derbesia tenuissima. Electron microscopy showed that the chloroplasts from both algae were sequestered intracellularly in juvenile slugs. Individuals offered any other macroalga, including the four calcareous species fed on by adults, did not feed on or incorporate any chloroplasts, and soon died. Juveniles switched from B. plumosa to P. capitatus at a length of ~ 1.0 cm, and fixed for microscopy 14 days later had intact intracellular chloroplasts from both algae.

Halimeda (Chlorophyta, Bryopsidales) (Lamouroux 1812) is a genus of calcareous green algae that has become abundant on coral reefs of the tropics and subtropics. Though they serve biologically and geologically important roles in these ecosystems, their presence may be an indicator of declining environmental conditions. This study focused on a population of Halimeda in the shallow coastal waters of Tavernier, Florida. Three species were encountered: Halimeda discoidea, Halimeda opuntia, and Halimeda incrassata; Halimeda discoidea was the most abundant. The study was conducted in two parts. Part one involved the observation and quantification of the life history characteristics (e.g. fertility rate, growth rate, mortality rate) of the collected specimens in an artificial environment. Population numbers increased throughout the five week study as new individuals were added through vegetative reproduction. Sexual reproduction was not observed. In Part two the life history characteristics of H. discoidea were used in the construction of a size-classified transition matrix model. Sensitivity and elasticity analyses suggested that the population is most sensitive to changes in the survival rate of reproductive juveniles, and least sensitive to the survival of post-reproductive adults. A standard Chi-square test was used to examine the accuracy of the population distribution predicted by the model against the observed distribution during each week of the study. The test results confirmed the validity of the model; however further analysis of the matrix revealed that without the input of sexual recruits the population will go extinct. A random sexual component was then added to the matrix. Environmental stochasticity can have a direct affect on sexual recruitment in Halimeda. Recruitment interval and recruitment success influence the ability of the population to maintain itself. These factors were manipulated in the matrix. With a 25% recruitment interval of 50 recruits the simulated population was able to avoid extinction over a 25 year period. These results implicate that Halimeda populations require both sexual and asexual recruitment. Additionally, the patchy distribution of Halimeda on and near coral reefs of south Florida indicates that the population may actually be a metapopulation. Recommendations for further studies include an investigation of additional sub-populations within the metapopulation. A mortality analysis would also be useful for gaining a better understanding of the population dynamics and sediment contributions of Halimeda in south Florida.

The brine shrimp lethality assay was used as a preliminary tool to screen eighteen seaweeds collected from the South African coast. Of the seaweeds tested, the red algae Plocamium corallorhiza and Hypnea rosea, and the green alga Halimeda sp., showed the most potent activity. The chemical investigation of P. corallorhiza resulted in the isolation and structural elucidation of five previously undescribed secondary metabolites, along with three known compounds and four possible artifacts of the extraction process. Standard spectroscopic methods and comparison with known compounds were used to determine the structures of the new metabolites. The new compounds included the linear halogenated monoterpenes 4,8-dibromo-1, 1-dichloro-3,7-dimethyl-2,6-octadiene (99), 4,6-dibromo-l, 1-dichloro-3,7-dimethyl-2,7-octadiene (100), 4,8-dibromo-l, 1,7-trichloro-3,7-dimethyl-2,5-octadiene (101) and 3,4,6,7-tetrachloro-3,7-dimethyl-l-octene (102) and the cyclic monoterpene 5-bromo-5-bromomethyl-I-chlorovinyl-2,4-dichloro-methylcyclohexane (103) while the known compounds were identified as 4-bromo-5-bromomethyl-1chlorovinyl-2,5-dichloro-methylcyclohexane (35), 1,4,8-tribromo-3, 7 -dichloro-3,7-dimethyl-1,5-octadiene (94) and 8-bromo-1,3,4,7-tetrachloro-3,7-dimethyl-1,5-octadiene (96). The four methoxylated compounds (104-107) were presumably formed via a standard substitution reaction between the halogenated monoterpenes 96 and 101 and MeOH, which was used as a component in the extraction solvent. With over 100 000 natural products having been reported, it has become necessary to employ an efficient dereplication strategy to quickly identify known compounds. A simple Gas Chromatography-Mass Spectrometry (GC-MS) method for the efficient physicochemical screening, identification and dereplication of Plocamium metabolites was developed. In this study the crude extracts of P. corallorhiza, P. cornutum and P. maxillosum were screened by GC-MS and the retention times and mass spectral fragmentation patterns of compounds 94, 96, 99 - 107 were used to quickly identify known and new compounds in the crude extracts of P. cornutum and P. maxillosum. This data indicated that compounds 99, 100, 103 were present in both P. corallorhiza and P.cornutum, while compound 102 was found to be present in P. corallorhiza, P. cornutum and P. maxillosum. These studies also indicated that ecotypes and chemotypes are not a significant feature of P. corallorhiza and P. cornutum. Different species of Plocamium (namely: P. corallorhiza, P. cornutum, and P. maxillosum) have very different chemical profiles, and GC may therefore have appreciable taxonomic application in the identification of the different Plocamium spp. which are endemic to South Africa.

Submitted by Pedro Barros (pedro.silvabarros@ufpe.br) on 2018-09-20T22:26:49Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) DISSERTAÇÃO Vanessa Gabriela Barbosa de Mendonça.pdf: 2616124 bytes, checksum: f417338ffbaebe9fab008a107dd2a092 (MD5) / Approved for entry into archive by Alice Araujo (alice.caraujo@ufpe.br) on 2018-09-21T17:08:15Z (GMT) No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) DISSERTAÇÃO Vanessa Gabriela Barbosa de Mendonça.pdf: 2616124 bytes, checksum: f417338ffbaebe9fab008a107dd2a092 (MD5) / Made available in DSpace on 2018-09-21T17:08:15Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) DISSERTAÇÃO Vanessa Gabriela Barbosa de Mendonça.pdf: 2616124 bytes, checksum: f417338ffbaebe9fab008a107dd2a092 (MD5) Previous issue date: 2017-03-14 / CNPq / Os problemas ambientais associados a crise de falta de água tem se tornado cada vez mais frequentes, e suas consequências são alarmantes. A indústria têxtil é responsável pela geração de grandes volumes de águas residuais, os quais são muitas vezes lançados nos corpos hídricos sem tratamento adequado. Além do efeito visual, a presença de corantes têxteis nos efluentes é tóxica aos seres vivos e aos organismos marinhos, dificultando a penetração da luz solar e interferindo na atividade fotossintética. Processos de tratamento por adsorção são aplicados na remoção de corantes nos efluentes provenientes das industrias do setor têxtil. Pesquisas por novos adsorventes buscam materiais eficientes. O objetivo desse trabalho consiste em avaliar a remoção do corante têxtil Indosol Escarlate por adsorção com macroalgas verdes Halimeda opuntia pertencente à ordem Bryopsidales (Chlorophyta). Inicialmente foi realizado tratamento ácido na alga in natura. Após permanecer imersa na solução ácida (H₂SO₄ concentração 0,5 mol.L⁻¹) por 5 minutos, a biomassa foi lavada e seca em estufa à 60 ºC por 24 horas. As micrografias comprovaram eficácia do tratamento com ácido, sendo observado maior agrupamento entre as partículas. A análise de superfície específica e porosidade (BET) evidenciou aumento percentual de 103,92% na área superficial do material adsorvente após este ser calcinado à temperatura de 1000ºC por 10 horas. O material adsorvente tratado revelou possuir área superficial grande (127 m².g⁻¹) se comparado com outros organismos. A espécie é amplamente encontrada no litoral de Pernambuco. Estudos preliminares alcançaram capacidade adsortiva de aproximadamente 22 mg.g⁻¹ ainda nos primeiros 7 minutos de adsorção (Cᴀ₀ = 50 mg.L⁻¹; Volume = 25mL; Massa = 0,05g; 400 rpm, T = 27,8 ºC). Apesar disso, o estudo do equilíbrio foi realizado em 120 minutos para garantir total aproveitamento. Os experimentos foram realizados em batelada e os resultados dos planejamentos fatoriais foram: Todos os efeitos analisados demonstram-se estatisticamente significativos em relação à capacidade adsortiva. As variáveis analisadas foram a velocidade de agitação (rpm), a granulometria, a temperatura e o tempo de calcinação. As isotermas de adsorção seguiram o modelo de Langmuir-Freundlich (30ºC, 45ºC e 65ºC), com capacidade adsortiva máxima (qₘₐₓ) à 65ºC igual a 145,67 mg.g⁻¹. O estudo termodinâmico mostrou que a reação de adsorção é espontânea, visto que a variação da energia livre de Gibbs foi negativa. O valor positivo da variação da entalpia sugeriu que a reação é endotérmica. No estudo da cinética, os resultados apresentaram melhor ajuste ao modelo de pseudo-segunda ordem, e as simulações dinâmicas demonstraram o decaimento da concentração do corante e o aumento da capacidade de adsorção ao longo do tempo. Concluiu-se que as algas Halimeda opuntia podem ser consideradas como bons candidatos para serem adsorventes do corante Indosol Escarlate. / The environmental problems associated with the lack of water has become increasingly common, and its consequences are alarming. The textile industry produces large amounts of waste, which are often not adequately treatments. In addition to the visual effect, the presence of dye in the effluent is toxic to marine organisms, interfering with the penetration of sunlight thereby impairing the photosynthetic activity. Searches are conducted to find new, more efficient materials. In this paper, the technique of adsorption were used for removal of Indosol Escarlate textile dye with green macroalgae Halimeda opuntia belonging to Bryopsidales order (Chlorophyta). Initially, acid treatment was carried out in the algae in natura. After remaining immersed in the acid solution (H₂SO₄ concentration 1N) for 5 minutes, the biomass was washed and oven dried at 60 °C for 24 hours. The micrographs confirmed the efficacy of the treatment with acid, so that larger grouping was observed among the particles. The analysis of specific surface and porosity (BET) evidenced a percentage increase of 103.92% in the surface area of the adsorbent material after it was calcined at 1000ºC for 3 hours. The treated adsorbent material revealed to have a large surface area (127 m².g⁻¹) when compared to other organisms. The species is widely found on the coast of Pernambuco. Preliminary studies reached adsorption capacity of approximately 22 mg.g⁻¹ in the first 7 minutes of adsorption (Cᴀ₀ = 50 mg.L⁻¹; V= 25mL; M = 0,05g; 400 rpm, T = 27,8 ºC). Nevertheless, the balance study was conducted in 120 minutes to ensure complete recovery. The experiments were conducted in batches and the best conditions found by technique of factorial design were: The effects of the agitation speed (rpm), the calcination temperature (ºC) and the size (μm) of the adsorbent material were statistically significant in relation to the adsorptive capacity. The effect of the calcination time (h) was not significant within the studied range. The adsorption isotherms followed the model of Langmuir-Freundlich (30°C, 45°C and 65°C), and maximum adsorption capacity (65°C) was 145.67 mg.g⁻¹. The thermodynamic study showed that the process was spontaneous (ΔG < 0). The positive value of enthalpy (ΔH > 0) suggests that the reaction is endothermic. In kinetic studies, the results showed better adjustment to the model of pseudo-second order, and dynamic simulations have shown the decrease of the dye concentration and the increase in adsorption capacity over time. It was concluded that Halimeda opuntia algae can be considered as good candidates to be adsorbent of the Indosol Scarlet dye.

Thesis (M.S.)--University of North Carolina at Wilmington, 2004. / Includes bibliographical references (leaves : [35]-41).

While ocean acidification (OA) is predicted to inhibit calcification in marine macroalgae, species whose photosynthesis is limited by current dissolved inorganic carbon (DIC) levels may benefit. Furthermore, variations in macroalgal morphology will likely give rise to a range of OA tolerance in calcifying macroalgae. One genus of calcifying macroalgae that has shown varying species’ tolerance to OA is Halimeda, a major carbonate sediment producer on tropical reefs. Species within this genus occupy a range of habitats within tropical environments (reefs and lagoons), illustrating their ability to adapt to diverse environmental conditions (e.g. carbonate chemistry, irradiance). To date it is not clear if morphological and photophysiological diversity in Halimeda will translate to different tolerances to OA conditions (elevated pCO2 and lower pH). / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection

Phylloid-algal mounds form heterogeneous hydrocarbon reservoirs in the southeastern portion (Blanding sub-basin) of the Paradox Basin. Well-studied Lower Ismay mounds exposed along walls of the San Juan River gorge in the vicinity of Eight Foot Rapids, the west limb of the Raplee Anticline, and at the classic Honaker Trail locality (southwestern Paradox Basin) have often been cited as outcrop analogs of productive subsurface mounds. Until now, however, there has not been a complete description of the distribution, size, and spacing of outcropping algal mounds at the classic Eight Foot Rapids locality. The Lower Ismay sequence was analyzed in the context of a build-and-fill model of deposition. There are three facies associations within the sequence: 1) a basal lowstand to middle highstand pre-mound facies association, 2) a late highstand to middle falling stage phylloid algal-dominated relief-building facies association, and 3) a late falling stage, post-mound relief-filling facies association. Above the basal maximum flooding surface (Gothic Shale), the facies succession displays a distinct shallowing upward trend through the Lower Ismay sequence. Mound dimensions and facies stacking patterns permit evaluation of two depositional models. The first is a traditional, moderate- to low-energy model of vertical and radial mound accumulation of phylloid algal plates. The second is a high-energy, tidally influenced model of accumulation wherein mounds become hydrodynamically elongate. Outcrop data indicate that algal-dominated buildups are domal in shape with no preferred axis of elongation. These patterns do not support a hydrodynamic accumulation of loose algal plate fragments. The absence of in-situ algal thalli in all but the upper few tens of centimeters of the mounds, however, argues against a purely biological/ecological origin of mounds. A down-stepping ramp model is proposed wherein a muddy algal facies was deposited at the base of the mounds in the low energy of the outer ramp, followed by a grain-rich algal core in the mid-ramp environment. Mounds tops accumulated in an algal bafflestone facies in the inner ramp setting. Restriction of energy due to basinward algal buildup may have also contributed to deposition of algal bafflestone. Mounds accumulated radially at differential rates and were influenced by these variations in energy. This differential deposition of microfacies and subsequent diagenetic alteration have produced heterogeneities in algal reservoir rock, producing algal mound reservoirs that have a high potential for compartmentalization.