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Macroalgae response to a mercury contamination gradient in a temperate coastal lagoon (Ria de Aveiro, Portugal)

Coelho, J. P.; Pereira, M. E.; Duarte, A.; Pardal, M. A.
Fonte: Universidade de Coimbra Publicador: Universidade de Coimbra
Tipo: Artigo de Revista Científica Formato: aplication/PDF
ENG
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37.44%
Primary producers represent an important pathway for mercury incorporation in aquatic food webs. With eutrophication processes occurring worldwide, macroalgae may represent a substantial pool of mercury, as a result of its high growth rate and capacity to bind trace metals. The main aim of this work was to evaluate the response of the macroalgae to a human-induced environmental mercury gradient in a temperate coastal lagoon, by assessing the total and organic mercury contamination levels of the dominant species (Enteromorpha, Fucus and Gracilaria). Total mercury in the plant tissues ranged from 0.02 to 2.1 [mu]g g-1 dwt. Fucus was the most contaminated algae, followed by Gracilaria and Enteromorpha. As a whole, organic mercury never exceeded 15% of total mercury content, but tended to increase with distance to metal source on all macroalgae indicating complex physiological responses from these primary producers in areas of high and low mercury concentrations. Sessile macroalgae may be important mercury immobilisation agents, while free-floating algae (Enteromorpha) play an important role in mercury transport from contaminated areas (±10 g ha-1) to other areas of the lagoon and even to coastal waters. Based on the present results the use of macroalgal biomass from contaminated areas for direct or indirect human use (e.g. agricultural...

The influence of sulfathiazole on the macroalgae Ulva lactuca

Leston, Sara; Nunes, Margarida; Viegas, Ivan; Nebot, Carolina; Cepeda, Alberto; Pardal, M. A.; Ramos, Fernando
Fonte: Elsevier Ltd. Publicador: Elsevier Ltd.
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
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Sulfonamides (SA) are a class of antibiotics routinely found in environmental matrices and therefore their role as contaminants should be investigated in non-target organisms. With this purpose the present experimental work has evaluated the exposure of the chlorophycean Ulva lactuca L. to sulfathiazole (STZ), a SA drug commonly used in aquaculture, at two concentrations representing prophylactic (25 lgmL 1) and therapeutic (50 lgmL 1) administrations. Results showed that STZ exhibits high stability in seawater with only 18% degradation over the 5 d assay at both dosages tested. Also, macroalgae demonstrated an efficient uptake capacity with constant internal concentrations after 24 h regardless of the external solutions and thus should be considered as a bioindicator species in risk assessment. Both STZ concentrations induced a slight inhibition of the macroalgae growth after 96 h.; This work was funded by FEDER through the Operational Program for Competitiveness Factors – COMPETE and by FCT – Portuguese Foundation for Science and Technology under the Grant attributed to Sara Leston (SFRH/BPD/91828/2012) and through the Project PTDC/AGR-ALI/122119/2010.

Macroalgas marinhas associadas a bancos de rodolitos do infralitoral do Espírito Santo, Brasil; Marine macroalgae associated to rodoliths beds from Espírito Santo state, Brazil

Pacheco, Mariana Rodrigues
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 18/02/2011 PT
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Macroalgas têm sido descritas no Brasil desde a região entremarés até cerca de 120 metros de profundidade na plataforma continental. O objetivo deste trabalho foi a caracterização da flora marinha bêntica em bancos de rodolitos entre 20-30 metros de profundidade, do infralitoral sul do estado do Espírito Santo. Os métodos utilizados neste projeto incluíram a coleta meticulosa de material através de mergulho autônomo, que preserva o material mais frágil em contraste com a utilização de dragagem. Estudos no infralitoral do estado do Espírito Santo são muito escassos. Esta flora é conhecida principalmente pela análise de material arribado nas praias e proveniente de algumas dragagens e mergulhos. Este trabalho procura contribuir para o inventário da flora de algas marinhas brasileiras, assim como contribuir para o conhecimento da biodiversidade de macroalgas enfocando especialmente a flora do infralitoral através de um estudo sistemático, descrevendo e ilustrando os aspectos mais importantes das espécies encontradas. Foram identificados 138 táxons de algas marinhas, sendo 77,5% (107 táxons) representantes do Filo Rhodophyta, 11,6% (16 táxons) representantes do Filo Chlorophyta e 10,9% (15 táxons) representantes da Classe Phaeophyceae. Observou-se também que a riqueza de espécies de macroalgas no inverno decresce acentuadamente em relação ao período de verão. Esta redução na riqueza de espécies pode ser explicada pela instabilidade gerada nos bancos de rodolitos no período de inverno...

Diversidade de macroalgas da Baía do Almirantado, ilha Rei George, Península Antártica, baseada em 'DNA barcoding' e outros marcadores moleculares; Macroalgae diversity of admiralty bay, King George Island, Antarctic Peninsula based on DNA Barcoding and other molecular markers

Medeiros, Amanda da Silva
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 22/10/2013 PT
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Baseado em estudos morfológicos, as macroalgas marinhas da Baía do Almirantado (Ilha Rei George, Península Antártica) estão representadas por 55 táxons, sendo 30 Rhodophyta, 16 Phaeophyceae e 9 Chlorophyta. Recentemente foi proposta a utilização de 'DNA barcode' para uma rápida e acurada identificação de espécies de macroalgas. Sendo a região 5' do gene mitocondrial cox 1utilizado para identificação de algas vermelhas e pardas; o gene plastidial tufA utilizado na identificação de algas verdes; e o domínio V do gene 23S rRNA - UPA, universal plastid amplicon, utilizado na identificação de organismos fotossintetizantes. O objetivo desse trabalho foi obter sequências do tipo 'DNA barcodes' e de outros marcadores filogenéticos para a formação do primeiro banco de dados moleculares para as macroalgas da Baía do Almirantado, Antártica. Cerca de 100 espécimes de macroalgas foram coletados, em diversos pontos da baía, durante as OPERANTARes XXV e XXIX, que ocorreram durante dezembro de 2006 a junho de 2007 e dezembro de 2010 a janeiro de 2011, respectivamente. No presente trabalho, foi obtido um total de 209 sequências, cobrindo 29 espécies das 55 citadas para o local, sendo que 157 sequências são para marcadores moleculares do tipo 'DNA barcode'...

Efeito dos parâmetros ambientais sobre a macroalga Gracilaria domingensis: estratégias de aclimatação e fotoproteção na espécie; Effects of environmental parameters on macroalgae Gracilaria domingensis: acclimation and photoprotection strategy on specie

Pereira, Dinaelza Castelo
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 31/10/2014 PT
Relevância na Pesquisa
37.25%
Em seu habitat natural as algas estão sujeitas a ação simultânea de vários fatores, como radiação (fotossinteticamente ativa e ultravioleta), temperatura, salinidade e disponibilidade de nutrientes, entre outros. A variação desses fatores no ambiente natural ocorre de forma coletiva e uma rápida resposta do organismo é determinante pra sua sobrevivência. Neste trabalho foram conduzidos experimentos relacionados aos efeitos da variação nos parâmetros ambientais sobre a macroalga Gracilaria domingensis. Três linhagens cromáticas dessa espécie foram cultivadas no mar, em diferentes épocas do ano (estações chuvosa e seca). Os dados fotossintéticos e bioquímicos foram acessados em uma escala de tempo referente às variações observadas durante o período de luz do dia e em uma escala referente às variações observadas em semanas. Os resultados obtidos a partir de análises dos parâmetros fotossintéticos, conteúdo pigmentar, concentração de glutationa, concentração de aminoácidos tipo micosporina, conteúdo tecidual de carbono, nitrogênio e fósforo, teor de lipídeos e ácidos graxos e rendimento do ágar mostraram alterações no perfil bioquímico e fisiológico da macroalga. Essas alterações foram correlacionadas com os fatores abióticos e sugerem alterações no metabolismo como uma das estratégias de aclimatação da espécie.; In their natural habitat algae are exposed to simultaneous action of various factors...

Aminoácidos tipo micosporina: novas metodologias e distribuição em macroalgas da costa brasileira; Mycosporine-like amino acids: new methodologies and distribution among macroalgae from the brazilian coast

Marques, Luiza Grecco e
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 29/04/2015 PT
Relevância na Pesquisa
37.5%
A radiação ultravioleta (RUV) causa efeitos deletérios em ecossistemas aquáticos e terrestres. Um dos mecanismos de defesa criados pelos organismos para evitar estes danos é o acúmulo de compostos que absorvem RUV, dentre os quais os aminoácidos tipo micosporina (MAAs, do inglês mycosporine-like amino acids) representam uma classe importante. As MAAs são substâncias solúveis em água caracterizadas pela presença de uma unidade ciclo-hexenona ou ciclo-hexenimina conjugada com nitrogênio substituído por um aminoácido, aminoálcool ou grupo amino, apresentando absorção máxima entre 308 e 362 nm e altos coeficientes de absortividade molar. Dado o importante papel desempenhado pelas MAAs na fisiologia e bioquímica celular de algas, seja atuando como protetoras de RUV ou como antioxidantes, o objetivo desta tese foi expandir o corpo de conhecimentos disponíveis sobre a ocorrência e distribuição destes compostos em macroalgas brasileiras. Para atingir tal meta, foi necessário desenvolver procedimentos analíticos de isolamento por cromatografia líquida de alta eficiência (high procedure liquid chromatography, HPLC), de modo a gerar padrões que pudessem ser utilizados para a qualificação e quantificação de MAAs em extratos de algas. Foi necessário também desenvolver dois novos métodos de análise por HPLC acoplada a espectrometria de massas (HPLC-MS) - sendo um utilizado como método diagnóstico...

Light-related photosynthetic characteristics of lotic macroalgae

Necchi, O.
Fonte: Kluwer Academic Publ Publicador: Kluwer Academic Publ
Tipo: Artigo de Revista Científica Formato: 139-155
ENG
Relevância na Pesquisa
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Photosynthetic characteristics in response to irradiance were analysed in 42 populations of 33 macroalgal species by two distinct techniques (chlorophyll fluorescence and oxygen evolution). Photosynthesis-irradiance (PI) curves based on the two techniques indicated adaptations to low irradiance reflected by low saturation values, high to moderate values of photosynthetic efficiency (alpha) and photoinhibition (beta), for Bacillariophyta and Rhodophyta, which suggests they are typically shade-adapted algae. In contrast, most species of Chlorophyta were reported as sun adapted algae, characterized by high values of I-k and low of alpha, and lack of or low photoinhibition. Cyanophyta and Xanthophyta were intermediate groups in terms of light adaptations. Photoinhibition was observed in variable degrees in all algal groups, under field and laboratory conditions, which confirms that it is not artificially induced by experimental conditions, but is rather a common and natural phenomenon of the lotic macroalgae. Low values of compensation irradiance (I-c) were found, which indicate that these algae can keep an autotrophic metabolism even under very low irradiances. High ratios (>2) of photosynthesis/respiration were found in most algae, which indicates a considerable net gain. These two physiological characteristics suggest that macroalgae may be important primary producers in lotic ecosystems. Saturation parameters (I-k and I-s) occurred in a relatively narrow range of irradiances (100-400 mumol photons m(-2) s(-1))...

Distribution of stream macroalgae in the eastern Atlantic Rainforest of São Paulo State, southeastern Brazil

Branco, Ciro Cesar Zanini; Necchi Jr., Orlando
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 139-150
ENG
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Fifty-two stream segments were sampled from 16 August to 13 September in 1993 in the eastern Atlantic Rainforest of São Paulo State, southeastern Brazil (22°55′-25°00′S, 44°48′-48°03′W). Forty-two macroalgal subgeneric taxa were found and the most widespread species were Audouinella pygmaea (21% of sites), Compsopogon leptoclados and Microcoleus subtorulosus (19%). Macroalgal species number per sampling site ranged from 0 to six (2.6 ± 1.7) and was positively correlated to species abundance, whereas species cover ranged from 0 to 70% of the stream bed (15.5 ± 20.8%). No significant correlation was found among macroalgal species number and abundance with any physical or chemical variable analyzed. Most sites were dominated by one or few macroalgal species, mainly, Audouinella macrospora, C. leptoclados and M. subtorulosus. No significant difference was found between the frequency distribution of variables measured for streams and for total macroalgae but the most widespread species (A. pygmaea) differed significantly for current velocity, specific conductance, turbidity and pH. Overall means for macroalgal occurrence include the following values: temperature (X̄ = 19.9°C), current velocity (X̄ = 45 cm s-1), oxygen saturation (X̄ = 66%)...

The effects of habitat complexity and hydraulic conditions on the establishment of benthic stream macroalgae

Tonetto, Aurelio Fajar; Cardoso-Leite, Ricardo; Peres, Cleto K.; Bispo, Pitagoras da Conceição; Branco, Ciro Cesar Zanini
Fonte: Wiley-Blackwell Publicador: Wiley-Blackwell
Tipo: Artigo de Revista Científica Formato: 1687-1694
ENG
Relevância na Pesquisa
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Processo FAPESP: 07/52608-1; Processo FAPESP: 12/21196-8; Processo FAPESP: 10/17563-0; 1. Habitat complexity is thought to play an important role in various ecological communities, but its role under variable natural conditions is not well understood, particularly in lotic habitats where the complexity of the substratum influences the diversity and abundance of the benthic community.2. We investigated the effects of the habitat complexity of the substratum, as represented by fractal structure, on the establishment of stream macroalgae. We also analysed the influence of hydraulic conditions associated with variations in the fractal dimension of the substratum. We hypothesised that habitats with higher surface complexity would have higher macroalgal abundance and that hydraulic conditions would affect macroalgal establishment differently on surfaces of differing complexity.3. We designed a field experiment to elucidate the role of habitat complexity (represented by the fractal dimension and density of roughness elements) and consequent hydraulic conditions (assessed by the Reynolds number and drag forces) on algal growth. Sterile artificial substrata with five levels of complexity were placed in four unshaded streams. After 60 days of complete submergence...

Effects of crevice size on the establishment of macroalgae in subtropical streams

Tonetto, A. F.; Peres, C. K.; Khnayfes, M. A.; Branco, C. C. Z.
Fonte: Instituto Internacional de Ecologia Publicador: Instituto Internacional de Ecologia
Tipo: Artigo de Revista Científica Formato: 803-809
ENG
Relevância na Pesquisa
37.36%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Processo FAPESP: 2007/52608-1; Processo FAPESP: 2010/17563-0; Considering that in previous studies, the surface roughness (micrometric dimension) showed a weak effect on the colonization of stream macroalgae, we investigated the effects of different crevice sizes (milimetric dimension, a scale slightly higher than previous investigations) on the macroalgal abundance in three streams exposed to full sunlight in southern Brazil. We used smooth sterile glass plates with different shapes: P – plane surface without crevices; S – sinuous surface (depth of crevices with 0.159 mm ± 0.03); N – non-unifom surface (0.498 mm ± 0.09); C – surfaces with convex structures (1.190 mm ± 0.12); and three additional surface types with different patterns of heterogeneity with combinations of glass pieces: P + S (H1); P + S + N (H2) and P + S + N + C (H3). The plates were placed into the streams and after 105 days the percent cover of macroalgal community was measured. No significant differences among treatments were recorded. However...

Faunal differences between the invasive brown macroalga Sargassum muticum and competing native macroalgae

Engelen, Aschwin; Primo, Ana; Cruz, Teresa; Santos, Rui
Fonte: Universidade de Évora Publicador: Universidade de Évora
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
37.55%
Interactions between macroalgae and their associated fauna are of great interest for marine invasions, because fauna may increase the biotic resis- tance of a system and macroalgal invasions may cause shifts in faunal composition. We tested for differences in faunal community structure between a macroalgal invader, Sargassum muticum, and several native mac- roalgae in intertidal pools on both the west and south coast of Portugal. On each coast, we compared the faunal diversity and composition associated with the invader with that of the competing native macroalga(e). On the west coast, the diversity of the fauna associated withS. muticum was equal to or lower than with the native competitor, Cystoseira humilis. Fauna composition differed between S. muticum and C. humilis at both locations, but within each species, no differences between locations were detected. In contrast, the fauna diversity on S. muticum of the south coast varied among locations. S. muticum fauna differed from the fauna of all native macroalgae at one location, but only from three out of seven native macroalgae at the other location. Discriminating fauna species did not show a consistent pattern towards higher or lower abundances in S. muti- cum compared to most native macroalgae...

Distinct fatty acid profile of ten brown macroalgae

Silva,Graça; Pereira,Renato B.; Valentão,Patrícia; Andrade,Paula B.; Sousa,Carla
Fonte: Sociedade Brasileira de Farmacognosia Publicador: Sociedade Brasileira de Farmacognosia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2013 EN
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It is widely accepted that the consumption of ω-3 polyunsaturated fatty acids has beneficial effects on human health. In this work, ten brown macroalgae species collected along the Portuguese west coast were studied for their fatty acids composition by GC-MS after alkaline hydrolysis and derivatization. The results of this survey showed that different macroalgae from the same region display distinct fatty acids profile. Concerning ω-3 polyunsaturated fatty acids, eicosapentaenoic acid was found in all but one species. Additionally, some species contained docosahexaenoic acid. Linoleic acid, an essential fatty acid of the ω-6 series, was present in all studied macroalgae. Fucus spiralis L. exhibited the highest amounts of monounsaturated fatty acids and of polyunsaturated fatty acids of the ω-3 and ω-6 series. The ω-6/ω-3 ratio in half of the studied species was lower than 1. This information reinforces the potential application of some brown macroalgae as dietary sources of polyunsaturated fatty acids.

Effects of crevice size on the establishment of macroalgae in subtropical streams

Tonetto,AF; Peres,CK; Khnayfes,MA; Branco,CCZ
Fonte: Instituto Internacional de Ecologia Publicador: Instituto Internacional de Ecologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/11/2014 EN
Relevância na Pesquisa
37.36%
Considering that in previous studies, the surface roughness (micrometric dimension) showed a weak effect on the colonization of stream macroalgae, we investigated the effects of different crevice sizes (milimetric dimension, a scale slightly higher than previous investigations) on the macroalgal abundance in three streams exposed to full sunlight in southern Brazil. We used smooth sterile glass plates with different shapes: P – plane surface without crevices; S – sinuous surface (depth of crevices with 0.159 mm ± 0.03); N – non-unifom surface (0.498 mm ± 0.09); C – surfaces with convex structures (1.190 mm ± 0.12); and three additional surface types with different patterns of heterogeneity with combinations of glass pieces: P + S (H1); P + S + N (H2) and P + S + N + C (H3). The plates were placed into the streams and after 105 days the percent cover of macroalgal community was measured. No significant differences among treatments were recorded. However, we observed a trend of macroalgae occurs within the crevices in all treatments and this suggests that, for stream macroalgae, the crevice sizes used in this study was still not enough to provide an expressive algal growth, even in the treatment with bigger crevices.

Tropical seagrass-associated macroalgae distributions and trends relative to water quality

Collado-Vides, Ligia; Caccia, Valentina G.; Boyer, Joseph N.; Fourqurean, James W.
Fonte: FIU Digital Commons Publicador: FIU Digital Commons
Tipo: Artigo de Revista Científica Formato: application/pdf
Relevância na Pesquisa
37.64%
Tropical coastal marine ecosystems including mangroves, seagrass beds and coral reef communities are undergoing intense degradation in response to natural and human disturbances, therefore, understanding the causes and mechanisms present challenges for scientist and managers. In order to protect our marine resources, determining the effects of nutrient loads on these coastal systems has become a key management goal. Data from monitoring programs were used to detect trends of macroalgae abundances and develop correlations with nutrient availability, as well as forecast potential responses of the communities monitored. Using eight years of data (1996–2003) from complementary but independent monitoring programs in seagrass beds and water quality of the Florida Keys National Marine Sanctuary (FKNMS), we: (1) described the distribution and abundance of macroalgae groups; (2) analyzed the status and spatiotemporal trends of macroalgae groups; and (3) explored the connection between water quality and the macroalgae distribution in the FKNMS. In the seagrass beds of the FKNMS calcareous green algae were the dominant macroalgae group followed by the red group; brown and calcareous red algae were present but in lower abundance. Spatiotemporal patterns of the macroalgae groups were analyzed with a non-linear regression model of the abundance data. For the period of record...

Macroalgae Decrease Growth and Alter Microbial Community Structure of the Reef-Building Coral, Porites astreoides

Thurber, Rebecca Vega; Burkepile, Deron E.; Correa, Adrienne M.S.; Thurber, Andrew R.; Schantz, Andrew A.; Welsh, Rory; Pritchard, Catharin
Fonte: FIU Digital Commons Publicador: FIU Digital Commons
Tipo: Artigo de Revista Científica Formato: application/pdf
Relevância na Pesquisa
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With the continued and unprecedented decline of coral reefs worldwide, evaluating the factors that contribute to coral demise is of critical importance. As coral cover declines, macroalgae are becoming more common on tropical reefs. Interactions between these macroalgae and corals may alter the coral microbiome, which is thought to play an important role in colony health and survival. Together, such changes in benthic macroalgae and in the coral microbiome may result in a feedback mechanism that contributes to additional coral cover loss. To determine if macroalgae alter the coral microbiome, we conducted a field-based experiment in which the coral Porites astreoides was placed in competition with five species of macroalgae. Macroalgal contact increased variance in the coral-associated microbial community, and two algal species significantly altered microbial community composition. All macroalgae caused the disappearance of a γ-proteobacterium previously hypothesized to be an important mutualist of P. astreoides. Macroalgal contact also triggered: 1) increases or 2) decreases in microbial taxa already present in corals, 3) establishment of new taxa to the coral microbiome, and 4) vectoring and growth of microbial taxa from the macroalgae to the coral. Furthermore...

The surplus value of Azorean macroalgae as health-promoting food. Protein, fiber, carbohydrates, lipids and vitamins determination

Lima, Elisabete; Furtado, Miguel; Garcia, Ismael G.; Paiva, Lisete S.; Baptista, José; Patarra, Rita F.; Neto, Ana I.
Fonte: Universidade dos Açores Publicador: Universidade dos Açores
Tipo: Conferência ou Objeto de Conferência
Publicado em //2012 ENG
Relevância na Pesquisa
37.36%
AICMA 2012 (BIT's 1st Annual International Congress of Marine Algae), World Expo Center, Dalian, China, 20-23 de Setembro.; Seaweeds are traditionally used in animal nutrition supplement and have also been an important human dietary component. In addition to their value as a human food supplement, seaweeds may also contribute as a functional o r health-promoting food to prevent some of the most degenerative diseases ofthe industrial countries. Over the past few decades, the consumption of seaweed products’ has increased in European countries. Currently, approxirnately 15-20 edible algae strains are being commonly marketed for consumption in Europe. In the archipelago of the Azores (Portugal), the consumption o f seaweeds is widespread and accepted as a common practice in some of the islands. Being isolated in the middle of the Atlantic Ocean and taking into account the low pollution levels of seawater in the region, the Azores Islands have become a very promising location as a natural resource for marine macroalgae with potential for providing new ingredients of so-called functional or health-promoting foods. In the present investigation we evaluate the crude protein and crude fiber content offive selected macroalgae (Chaetomorpha linum and Codium adhaerens...

Spatial variations at different observational scales and the seasonal distributions of stream macroalgae in a Brazilian subtropical region

Krupek,Rogério Antonio; Branco,Ciro Cesar Zanini; Peres,Cleto Kaveski
Fonte: Sociedade Botânica de São Paulo Publicador: Sociedade Botânica de São Paulo
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2012 EN
Relevância na Pesquisa
37.36%
We examined the relationships between environmental variations in lotic ecosystems with the seasonal dynamics of macroalgae communities at different spatial scales: drainage basin of two rivers (Rio das Pedras and Rio Marrecas), shading (open and shaded stream segments), mesohabitat (riffles and pools), and microhabitats. Data collections were made on a monthly basis between January and December/2007. A total of 16 taxa were encountered (13 species and 3 vegetative groups). All of the biotic parameters (richness, abundance, diversity, equitability, and dominance) were found to be highly variable at all of the spatial scales evaluated. On the other hand, abiotic variables demonstrated differences only at mesohabitat (in terms of current velocity) and shaded habitat (in terms of irradiance) scales. The seasonality of the macroalgae community structure was strongly influenced by microhabitat variables (current velocity, substrate H', and irradiance), demonstrating their importance over time and at different scales. Regional variables (temperature, oxygen saturation, specific conductance, pH, and turbidity) were found to have little influence on the temporal dynamics of the macroalgae communities evaluated.

Macroalgas bentónicas como sustrato y refugio de invertebrados marinos; Benthic macroalgae as substrate and refuge for marine invertebrates

Liuzzi, María Gabriela
Fonte: Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires Publicador: Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires
Tipo: info:eu-repo/semantics/doctoralThesis; tesis doctoral; info:eu-repo/semantics/publishedVersion Formato: application/pdf
Publicado em //2010 SPA
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Las macroalgas constituyen un sustrato favorable para el asentamiento de epibiontes y forman matrices tridimensionales que facilitan la supervivencia de macroinvertebrados en ambientes de elevao estrés. En esta tesis se abordaron cuatro líneas de trabajo tendientes a dilucidar las interacciones producidas entre las macroalgas bentónicas y los invertebrados marinos. Se estudió la composición y biogeografía de briozoos epibionts de macroalgas a lo largo de 29 grados de latitud a partir de muestras depositadas en el herbario del Museo Argentino de Ciencias Naturales. Aunque los patrones hallados están influenciados por la distribución desigual del esfuerzo de muestreo, puede concluirse que la biodiversidad de los briozoos y macroalgas es mayor en la Patagonia austral que en el litoral bonaerense y rionegrino. Se describe una nueva especie de briozoo antártico (Osthimosia chaotica) y se identifican otras dos nuevas especies, aún no descriptas. También se amplía la distribución geográfica para cuatro taxones. Se analizó el recambio taxonómico y las variaciones en la estructura del ensamble de macroinvertebrados asociado a coralináceas intermareales o diferentes escalas espaciales. Los resultados muestran que los cambios observados entre provincias son los más marcados...

Profiling of the molecular weight and structural isomer abundance of macroalgae-derived phlorotannins

Heffernan, Natalie; Brunton, Nigel P; Fitzgerald, Richard J.; Smyth, Thomas J
Fonte: MDPI Publicador: MDPI
Tipo: info:eu-repo/semantics/article; all_ul_research; ul_published_reviewed
ENG
Relevância na Pesquisa
37.36%
peer-reviewed; Phlorotannins are a group of complex polymers of phloroglucinol (1,3,5-trihydroxybenzene) unique to macroalgae. These phenolic compounds are integral structural components of the cell wall in brown algae, but also play many secondary ecological roles such as protection from UV radiation and defense against grazing. This study employed Ultra Performance Liquid Chromatography (UPLC) with tandem mass spectrometry to investigate isomeric complexity and observed differences in phlorotannins derived from macroalgae harvested off the Irish coast (Fucus serratus, Fucus vesiculosus, Himanthalia elongata and Cystoseira nodicaulis). Antioxidant activity and total phenolic content assays were used as an index for producing phlorotannin fractions, enriched using molecular weight cut-off dialysis with subsequent flash chromatography to profile phlorotannin isomers in these macroalgae. These fractions were profiled using UPLC-MS with multiple reaction monitoring (MRM) and the level of isomerization for specific molecular weight phlorotannins between 3 and 16 monomers were determined. The majority of the low molecular weight (LMW) phlorotannins were found to have a molecular weight range equivalent to 4-12 monomers of phloroglucinol. The level of isomerization within the individual macroalgal species differed...

Macroalgae as feedstock for cultivation of marine bacteria; Macroalgas como matéria-prima para a cultura de bactérias marinhas

França, Lucas Vagueiro de
Fonte: Universidade de Aveiro Publicador: Universidade de Aveiro
Tipo: Dissertação de Mestrado
ENG
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Alginate, laminarin and mannitol amount up to 60% of dry weight in brown macroalgae. The presence of alginate and laminarin-degrading enzymes and mannitol metabolic machinery have been confirmed by Matís, a partner in European BlueGenics project. Thus, in a biorefinery perspective, R. marinus can potentially perform the saccharification and fermentation of brown macroalgae carbohydrates to yield commercial valuable biocompounds, as thermostable enzymes and glycosidic carotenoids. Rhodothermus marinus is a moderate thermophilic (65ºC) and slight halophilic (1.0% NaCl) marine bacterium. Therefore, one of the objectives of this project was to decrease the NaCl concentration in the fermentation medium, since chloride leads to a lower equipment lifetime due to stainless steel corrosion of bioreactors. The main objective of this work was the study of the bacterium R. marinus pattern of growth when cultivated in the main brown macroalgal carbohydrates. This work was performed with five R. marinus strains, two of which were successfully acclimatized to cultivation in Medium 166, cryopreserved in glycerol and recultivated in liquid media, being subject of study in the assays with different carbon and sodium sources in shake flask. The growth studies with different carbon sources suggested that (i) strain 5 presented higher glucose consumption and growth...