994 resultados para Cystoseira abies-marina
Resumo:
Article sobre la tolerància a la sequera i les necessitats de llum d'espècies de l'alt i baix sublitoral de macroalgues de la Mediterrània del gènere Cystoseira C. Agardh (Fucales, Phaeophyceae)
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Para la elección del contenido del trabajo he seguido el mismo esquema utilizado para la presentación de las memorias de las prácticas académicas realizadas para la obtención de la diplomatura en navegación marítima y de la licenciatura en náutica y transporte marítimo. El modelo se basa en realizar un análisis de todos los equipamientos e instrumentación que podemos encontrar a bordo. Si nos fijamos en lo que establece la Orden del Ministerio de Transporte, Turismo y Comunicaciones de 18 de octubre de 1989 podríamos afirmar que la temática del presente trabajo se enmarcará dentro de los epígrafes “Seguridad a bordo, contra incendios, emergencias, supervivencia y salvamento” y “Equipamiento e instrumentación de a bordo”.El trabajo que les presento a continuación analiza el equipamiento del buque Nura Nova. El último de los tres buques en los que he estado embarcado como alumno de puente. El trabajo está dividido en varios apartados principales: Equipos de navegación, protección, comunicación, salvamento, contra incendios, carga y descarga y lucha contra la contaminación. Además de los apartados anteriores que forman el cuerpo central del trabajo, hay otros capítulos secundarios que ayudan a completarlo, como el capítulo que abre el trabajo y que narra brevemente la historia del Nura Nova.
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Se ha estudiado, basándose en una exhaustiva recopilación bibliográfica, la distribución mundial del género Cystoseira, que incluye una cincuentena de especies. Para cada especie se ha delimitado su área de distribución, lo que nos permite calcular el número de especies de este género existentes en las distintas áreas geográficas. El 80% de las especies de este género se encuentra en el Mediterráneo y Atlántico europeo y africano (desde Escocia a Cabo Verde), mientras que el 20% restante está distribuido en el mar Caribe, mar Rojo, océano índico y océano Pacífico.
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Sobre els aqüifers costers, la intrusió marina i la retirada del Plà Hidrològic Nacional
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We performed a study on the specific composition, structure, and dynamics of two Cystoseira mediterranea communities from the north-western Mediterranean submitted to different degrees of pollution. The structural complexity (species richness, specific distribution, and species and pattern diversity) and biomass production were lower in the polluted site. In this station, opportunistic algae (mainly Ulva rigida) loomed, and Mesophyllum lichenoides and some encrusting brown algae increased their cover. Other species (Jania rubens, and some Ceramiales) decreased their abundance when compared with the polluted site
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Kirja-arvio
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Merten aluesuunnittelu on keskeinen osa komission sinisen kasvun strategiaa ja EU:n yhdennettyä meripolitiikkaa. Euroopan parla-mentti on hiljattain hyväksynyt merten aluesuunnittelua koskevan direktiivin, jonka tarkoituksena on auttaa EU-maita koordinoimaan paremmin merellä toteutettavia toimia ja varmistaa, että toimet ovat tehokkaita ja ekologisesti kestäviä. Rannikko- ja merialueilla samasta tilasta ja resursseista kilpailevat monenlaiset toimet: kalastusalueet, vesiviljelylaitokset ja merten suojelualueet, meri-infrastruktuurit kuten kaapelit, putket ja laivaväylät sekä öljy- ja kaasulaitokset ja tuulivoimalat. Uusi direktiivi auttaa välttämään näinkin erilaisten käyttötarkoitusten välisiä potentiaalisia ristiriitoja ja luomaan vakaan toimintaympäristön, joka houkuttelee sijoittajia ja edistää näin kestävää kasvua. Suunnittelulla myös vähennetään nykyistä ylisääntelyä ja hallinnollisia kiemuroita. Moni toimet edellyttävät lupaa tai lisenssiä jotta ne saisivat toimia merialueilla ja viranomaiset vaativat usein että hakija suorittaa ympä-ristövahinkoarvioinnin (YVA), joka viranomaiset arvioivat ennen lupaa myönnetään. Oppaan tarkoitus on helpottaa hakijan YVA läpivienti tai hankinta tarjoamalla yleiskatsausta menetelmistä meriympäristön tutkimiseen ja niiden sopivuutta eri tarkoituksiin.
Resumo:
Shallow coastal areas are dynamic habitats that are affected by a variety of abiotic and biotic factors. In addition to the natural environmental stress, estuarine and coastal seagrass ecosystems are exposed to effects of climate change and other anthropogenic impacts. In this thesis the effect of different abiotic (shading stress, salinity and temperature) and biotic stressors (presence of co-occurring species) and different levels and combinations of stressors on the performance and survival of eelgrass (Zostera marina) was assessed. To investigate the importance of scale for stress responses, varying levels of biological organization (genotype, life stage, population and plant community) were studied in field and aquarium experiments. Light limitation, decreased salinity and increased temperature affected eelgrass performance negatively in papers I, II and III, respectively. While co-occurring plant species had no notable effect on eelgrass in paper IV, the presence of eelgrass increased the biomass of Potamogeton perfoliatus. The findings in papers II and III confirmed that more extreme levels of salinity and temperature had stronger impacts on plant performance compared to intermediate levels, but intermediate levels also had more severe effects on plants when they were exposed to several stressors, as illustrated in paper II. Thus, multiple stressors had negative synergetic effects. The results in papers I, II and III indicate that future changes in light climate, salinity and temperature can have serious impacts on eelgrass performance and survival. Stress responses were found to vary among genotypes, life stages and populations in papers I, II and III, respectively, emphasizing the importance of study scale. The results demonstrate that while stress in general affects seagrass productivity negatively, the severity of effects can vary substantially depending on the studied scale or level of biological organization. Eelgrass genotypes can differ in their stress and recovery processes, as observed in paper I. In paper II, eelgrass seedlings were less prone to abiotic stress compared to adult plants, but stress also decreased their survival considerably. This indicates that recruitment and re-colonization through seeds might be threatened in the future. Variation among population responses observed in paper III indicates that long-term local adaptation under differing selection pressures has caused divergence in salinity tolerance between Baltic eelgrass populations. This variability in stress tolerance observed in papers I and III suggests that some eelgrass genotypes and populations have a better capacity to adapt to changes and survive in a changing environment. Multiple stressors and biological level-specific responses demonstrate the uncertainty in predicting eelgrass responses in a changing environment. As eelgrass populations may differ in their stress tolerance both within and across regions, conservation strategies at both local and regional scales are urgently needed in order to ensure the survival of these important ecosystems.