Algal epiphytes of Zostera marina: Variation in assemblage structure from individual leaves to regional scale

Data from a hierarchical study of four Zostera marina beds in Wales were used to identify the spatial scales of variation in epiphyte assemblages. There were significant within and among bed differences in assemblage structure. The differences in assemblage structure with spatial scale generally persisted when species identifications were aggregated into functional groups. There was also significant within and among bed variability in Zostera density and average length. Local variations in Zostera canopy variables at the quadrat scale (total leaf length, average leaf length and leaf density per quadrat) were not related to epiphyte species richness nor to the structure of the assemblage. In contrast, individual leaf length was significantly related to species richness in two of the beds and the structure of epiphyte assemblages was always related to individual leaf lengths. The absence of links between quadrat scale measurements of canopy variables and assemblage structure may reflect the high turnover of individual Zostera leaves. Experimental work is required to discriminate further between the potential causes of epiphyte assemblage variation within and between beds. No bed represented a refuge where a rare species was abundant. If a species was uncommon at the bed scale, it was also uncommon in beds where it occurred. The heterogeneous assemblages found in this study suggest that a precautionary approach to conservation is advisable.

Expression pattern of arenicins - the antimicrobial peptides of polychaete Arenicola marina

Immune responses of invertebrate animals are mediated through innate mechanisms, among which production of antimicrobial peptides play an important role. Although evolutionary Polychaetes represent an interesting group closely related to a putative common ancestor of other coelomates, their immune mechanisms still remain scarcely investigated. Previously our group has identified arenicins - new antimicrobial peptides of the lugworm Arenicola marina, since then these peptides were thoroughly characterized in terms of their structure and inhibitory potential. In the present study we addressed the question of the physiological functions of arenicins in the lugworm body. Using molecular and immunocytochemical methods we demonstrated that arencins are expressed in the wide range of the lugworm tissues - coelomocytes, body wall, extravasal tissue and the gut. The expression of arenicins is constitutive and does not depend on stimulation of various infectious stimuli. Most intensively arenicins are produced by mature coelomocytes where they function as killing agents inside the phagolysosome. In the gut and the body wall epithelia arenicins are released from producing cells via secretion as they are found both inside the epithelial cells and in the contents of the cuticle. Collectively our study showed that arenicins are found in different body compartments responsible for providing a first line of defence against infections, which implies their important role as key components of both epithelial and systemic branches of host defence.

A ictiofauna da ria de Aveiro: estrutura, dinâmica e populações

O objectivo global deste trabalho consistiu em estudar aspectos da estrutura e dinâmica da ictiofauna da Ria de Aveiro, sistema lagunar estuarino com 43 km2 de extensão, em baixa-mar, que sofre influências dulçaquícolas e marinhas e fica situado entre 40º 30’-40º52’N and 8º35’-8º47W no litoral da costa Portuguesa. A ictiofauna foi capturada mensalmente, de Dezembro de 1996 a Novembro de 1997, em nove estações de amostragem dispersas pela laguna, com uma rede de pesca tradicional “chincha”. Foram também registados os seguintes parâmetros abióticos hidrológicos: temperatura, salinidade, oxigénio dissolvido e transparência. A temperatura variou entre 6,5 e 27,6ºC, a salinidade entre 0 e 41‰, o oxigénio dissolvido entre 1,2 e 11,4 mg.l-1 e a transparência entre 7,3 e 100,0%. A variação da salinidade e a transparência da água entre as estações de amostragem, assim como a variação da temperatura, salinidade e oxigénio dissolvido, ao longo dos meses, foram significativas. Foram capturados 14.598 exemplares pertencentes a 43 espécies de 21 famílias de Teleósteos. O número de espécies e densidade da ictiofauna foram mais elevados no Verão e nas estações mais perto da entrada da laguna, em especial na Barra e na Torreira, enquanto que a biomassa sofreu oscilações consideráveis ao longo dos meses e mostrou-se mais elevada nas estações mais afastadas da embocadura. As espécies marinhas sazonais foram as mais numerosas e registaram a maior biomassa e as categorias “marinha juvenil” e “estuarina residente” registaram o maior número de espécies. Mugilidae, Atherinidae e Clupeidae foram as famílias mais abundantes. Seis espécies representaram cerca de 74% da densidade total e cerca de 63% da biomassa total e ocorreram em todas as estações e em todos os meses. Pode-se concluir que a Ria de Aveiro, com elevada variação espacial e sazonal nos parâmetros abióticos, apresenta uma comunidade de peixes rica e representativa, comparada com lagunas costeiras estuarinas Europeias.

Estudo do impacto do ecoturismo na ictiofauna do Rio Sucuri (Bonito, MS, Brasil), utilizando as espécies de peixes Crenicichia lepidota (Heckel, 1840) e Moenkhausia bonita (Benine et al., 2004) como indicadores

Dissertação mest., Biologia Marinha, Universidade do Algarve, 2007

Caracterização da ictiofauna de intertidal rochoso na costa sul de Portugal

Dissertação mest., Biologia Marinha, Universidade do Algarve, 2009

Genetic structure at range edge: Low diversity and high inbreeding in Southeast Asian mangrove (Avicennia marina) populations

Understanding the genetic composition and mating systems of edge populations provides important insights into the environmental and demographic factors shaping species’ distribution ranges. We analysed samples of the mangrove Avicennia marina from Vietnam, northern Philippines and Australia, with microsatellite markers. We compared genetic diversity and structure in edge (Southeast Asia, and Southern Australia) and core (North and Eastern Australia) populations, and also compared our results with previously published data from core and southern edge populations. Comparisons highlighted significantly reduced gene diversity and higher genetic structure in both margins compared to core populations, which can be attributed to very low effective population size, pollinator scarcity and high environmental pressure at distribution margins. The estimated level of inbreeding was significantly higher in northeastern populations compared to core and southern populations. This suggests that despite the high genetic load usually associated with inbreeding, inbreeding or even selfing may be advantageous in margin habitats due to the possible advantages of reproductive assurance, or local adaptation. The very high level of genetic structure and inbreeding show that populations of A. marina are functioning as independent evolutionary units more than as components of a metapopulation system connected by gene flow. The combinations of those characteristics make these peripheral populations likely to develop local adaptations and therefore to be of particular interest for conservation strategies as well as for adaptation to possible future environmental changes.

Análise energética de uma unidade hoteleira do Algarve - caso de estudo Real Marina Hotel

Dissertação de mestrado, Energias Renováveis e Gestão de Energia, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2015

Contaminación marina en el Perú

Inventario de las principales fuentes de contaminación marina, debido a los desechos domésticos e industriales, hidrocarburos de petróleo e hidrocarburos clorinados, afín de mostrar el estado actual de la contaminación y su problemática, así como su legislación.

Estadísticas de los desembarques de la pesquería marina peruana 1983 - 1992

Reporta los desembarques de las principales 113 especies comercialmente más frecuentes entre peces, crustáceos, moluscos, equinodermos, quelonios, toninos y algas, de la abundante fauna y flora marina peruana.

Estadísticas de los desembarques de la pesquería marina peruana 1992 - 1993 - 1994

Resultados de las estadísticas de los desembarques de la pesquería marina peruana correspondiente a 1992, 1993 y 1994.