Short-term variability and trophic interactions within planktonic community in subtropical waters of he Canary Islands (Northeast atlantic)

ES]Los giros subtropicales abarcan grandes áreas del océano donde la productividad del ecosistema se sostiene a través del reciclado de materia y energía. En estas aguas, la interacción entre la disponibilidad de recursos y la presión de los niveles tróficos superiores determina la dinámica de la comunidad planctónica. Sin embargo, en aguas subtropicales, el conocimiento de la variabilidad temporal o el papel de los diferentes componentes de la comunidad dentro de la red trófica es bastante limitado. En esta tesis se evalúa la variabilidad a corto plazo de los diferentes componentes de la comunidad planctónica. El picoplancton dominó la comunidad salvo durante la época productiva, en la que los organismos autótrofos de mayor tamaño desempeñaron un papel destacado. Nuestros resultados muestran como la variabilidad estacional está relacionada con fuerzas “bottom-up”, mientras que los procesos “top-down” dominan a una escala de tiempo más corta. Encontramos que el microzooplancton ejerce un gran impacto sobre la comunidad microbiana, en organismos tanto autótrofos como heterótrofos. Además, observamos un acoplamiento muy estrecho entre estos consumidores y sus presas. Otro mecanismo que regula la estructura planctónica es la depredación de los migradores verticales sobre el zooplancton. Así, la variabilidad del mesozooplancton epipelágico está controlada por un ciclo de depredación vinculado a la iluminación de la luna. En este trabajo realizamos una simulación de esta variabilidad con la que se obtuvieron valores de mortalidad comunitaria de los que derivamos el flujo de carbono activo hacia la zona mesopelágica. Estos valores calculados de transporte activo de carbono son del mismo orden de magnitud que el flujo gravitacional en aguas subtropicales. En el Atlántico noreste la comunidad marina también podría estar influenciada por las tormentas de polvo sahariano que ocurren con gran frecuencia en la zona. En este sentido, se estudió la respuesta de la comunidad planctónica en un período de deposición de polvo atmosférico de gran intensidad, en el año 2010, sin observar una clara respuesta en términos de producción primaria. Por el contrario, la biomasa de diatomeas y mesozooplancton sí se vio aumentada en gran medida tras el paso de una fuerte tormenta de polvo del Sáhara, mientras que los organismos autótrofos de menor tamaño se vieron afectados negativamente. Los resultados de esta tesis suponen una contribución importante para entender la dinámica planctónica tan compleja en los ecosistemas subtropicales, y además, pone de manifiesto la necesidad de llevar a cabo muestreos oceanográficos a escalas de tiempo más cortas.

Spatial and temporal variation in settlement, growth and condition of the rockfish species Sebastes caurinus and Sebastes carnatus in the Channel Islands region, Santa Barbara, CA

Survival during the early life stages of marine species, including nearshore temperate reef fishes, is typically very low, and small changes in mortality rates, due to physiological and environmental conditions, can have marked effects on survival of a cohort and, on a larger scale, on the success of a recruitment season. Moreover, trade offs between larval growth and accumulation of energetic resources prior to settlement are likely to influence growth and survival until this critical period and afterwards. Rockfish recruitment rates are notoriously variable between years and across geographic locations. Monitoring of rates of onshore delivery of pelagic juveniles (defined here as settlement) of two species of nearshore rockfishes, Sebastes caurinus and Sebastes carnatus, was done between 2003-2009 years using artificial collectors placed at San Miguel and Santa Cruz Island, off Southern California coast. I investigated spatiotemporal variation in settlement rate, lipid content, pelagic larval duration and larval growth of the newly settled fishes; I assessed relationships between birth date, larval growth, early life-history characteristics and lipid content at settlement, considering also interspecific differences; finally, I attempt to relate interannual patterns of settlement and of early life history traits to easily accessible, local and regional indices of ocean conditions including in situ ocean temperature and regional upwelling, sea surface temperature (SST) and Chlorophyll-a (Chl-a) concentration. Spatial variations appeared to be of low relevance, while significant interannual differences were detected in settlement rate, pelagic larval duration and larval growth. The amount of lipid content of the newly settled fishes was highly variable in space and time, but did not differ between the two species and did not show any relationships with early life history traits, indicating that no trade off involved these physiological processes or they were masked by high individual variability in different periods of larval life. Significant interspecific differences were found in the timing of parturition and settlement and in larval growth rates, with S. carnatus growing faster and breeding and settling later than S. caurinus. The two species exhibited also different patterns of correlations between larval growth rates and larval duration. S. carnatus larval duration was longer when the growth in the first two weeks post-hatch was faster, while S. caurinus had a shorter larval duration when grew fast in the middle and in the end of larval life, suggesting different larval strategies. Fishes with longer larval durations were longer in size at settlement and exhibited longer planktonic phase in periods of favourable environmental conditions. Ocean conditions had a low explanatory power for interannual variation in early life history traits, but a very high explanatory power for settlement fluctuations, with regional upwelling strength being the principal indicator. Nonetheless, interannual variability in larval duration and growth were related to great phenological changes in upwelling happened during the period of this study and that caused negative consequences at all trophic levels along the California coast. Despite the low explanatory power of the environmental variables used in this study on the variation of larval biological traits, environmental processes were differently related with early life history characteristics analyzed to species, indicating possible species-specific susceptibility to ocean conditions and local environmental adaptation, which should be further investigated. These results have implications for understanding the processes influencing larval and juvenile survival, and consequently recruitment variability, which may be dependent on biological characteristics and environmental conditions.

Coastal flood vulnerability assessment with geomatic methods: Test sites of western Thailand, Sydney (Australia) and aeolian islands (south tyrrhenian sea, Italy)

The work undertaken in this PhD thesis is aimed at the development and testing of an innovative methodology for the assessment of the vulnerability of coastal areas to marine catastrophic inundation (tsunami). Different approaches are used at different spatial scales and are applied to three different study areas: 1. The entire western coast of Thailand 2. Two selected coastal suburbs of Sydney – Australia 3. The Aeolian Islands, in the South Tyrrhenian Sea – Italy I have discussed each of these cases study in at least one scientific paper: one paper about the Thailand case study (Dall’Osso et al., in review-b), three papers about the Sydney applications (Dall’Osso et al., 2009a; Dall’Osso et al., 2009b; Dall’Osso and Dominey-Howes, in review) and one last paper about the work at the Aeolian Islands (Dall’Osso et al., in review-a). These publications represent the core of the present PhD thesis. The main topics dealt with are outlined and discussed in a general introduction while the overall conclusions are outlined in the last section.

Geological and Structural evolution of the Eurasia Africa plate boundary in the Gulf of Cadiz Central Eastern Atlantic Sea.

Iberia Africa plate boundary, cross, roughly W-E, connecting the eastern Atlantic Ocean from Azores triple junction to the Continental margin of Morocco. Relative movement between the two plate change along the boundary, from transtensive near the Azores archipelago, through trascurrent movement in the middle at the Gloria Fracture Zone, to transpressive in the Gulf of Cadiz area. This study presents the results of geophysical and geological analysis on the plate boundary area offshore Gibraltar. The main topic is to clarify the geodynamic evolution of this area from Oligocene to Quaternary. Recent studies have shown that the new plate boundary is represented by a 600 km long set of aligned, dextral trascurrent faults (the SWIM lineaments) connecting the Gloria fault to the Riff orogene. The western termination of these lineaments crosscuts the Gibraltar accretionary prism and seems to reach the Moroccan continental shelf. In the past two years newly acquired bathymetric data collected in the Moroccan offshore permit to enlighten the present position of the eastern portion of the plate boundary, previously thought to be a diffuse plate boundary. The plate boundary evolution, from the onset of compression in the Oligocene to the Late Pliocene activation of trascurrent structures, is not yet well constrained. The review of available seismics lines, gravity and bathymetric data, together with the analysis of new acquired bathymetric and high resolution seismic data offshore Morocco, allows to understand how the deformation acted at lithospheric scale under the compressive regime. Lithospheric folding in the area is suggested, and a new conceptual model is proposed for the propagation of the deformation acting in the brittle crust during this process. Our results show that lithospheric folding, both in oceanic and thinned continental crust, produced large wavelength synclines bounded by short wavelength, top thrust, anticlines. Two of these anticlines are located in the Gulf of Cadiz, and are represented by the Gorringe Ridge and Coral Patch seamounts. Lithospheric folding probably interacted with the Monchique – Madeira hotspot during the 72 Ma to Recent, NNE – SSW transit. Plume related volcanism is for the first time described on top of the Coral Patch seamount, where nine volcanoes are found by means of bathymetric data. 40Ar-39Ar age of 31.4±1.98 Ma are measured from one rock sample of one of these volcanoes. Analysis on biogenic samples show how the Coral Patch act as a starved offshore seamount since the Chattian. We proposed that compression stress formed lithospheric scale structures playing as a reserved lane for the upwelling of mantle material during the hotspot transit. The interaction between lithospheric folding and the hotspot emplacement can be also responsible for the irregularly spacing, and anomalous alignments, of individual islands and seamounts belonging to the Monchique - Madeira hotspot.

Functional and Genetic characterization of new genomic islands from an E. coli strain associated with neonatal meningitis.

Enterobacteriaceae genomes evolve through mutations, rearrangements and horizontal gene transfer (HGT). The latter evolutionary pathway works through the acquisition DNA (GEI) modules of foreign origin that enhances fitness of the host to a given environment. The genome of E. coli IHE3034, a strain isolated from a case of neonatal meningitis, has recently been sequenced and its subsequent sequence analysis has predicted 18 possible GEIs, of which: 8 have not been previously described, 5 fully meet the pathogenic island definition and at least 10 that seem to be of prophagic origin. In order to study the GEI distribution of our reference strain, we screened for the presence 18 GEIs a panel of 132 strains, representative of E. coli diversity. Also, using an inverse nested PCR approach we identified 9 GEI that can form an extrachromosomal circular intermediate (CI) and their respective attachment sites (att). Further, we set up a qPCR approach that allowed us to determine the excision rates of 5 genomic islands in different growth conditions. Four islands, specific for strains appertaining to the sequence type complex 95 (STC95), have been deleted in order to assess their function in a Dictyostelium discoideum grazing assays. Overall, the distribution data presented here indicate that 16 IHE3034 GEIs are more associated to the STC95 strains. Also the functional and genetic characterization has uncovered that GEI 13, 17 and 19 are involved in the resistance to phagocitation by Dictyostelium d thus suggesting a possible role in the adaptation of the pathogen during certain stages of infection.

Effect of Paramuricea clavata (Risso, 1826) "forest" on the benthic populations of Tremiti Islands Effetto "foresta" di Paramuricea clavata (Risso, 1826) sui popolamenti bentonici delle Isole Tremiti

Mediterranean coralligenous habitats are biogenic reefs characterised by high species diversity and built mainly by encrusting calcareous red algae, growing in dim light conditions. The global climate change and several human activities may threaten species living in these habitats, especially some of those that are considered particularly relevant in structuring and in maintaining the complexity and diversity of the benthic assemblages. Among them, the red gorgonian, Paramuricea clavata (Risso, 1826), which can form dense populations, in the last decades showed worrying mass mortality events. Understand the role of this “animal forests” in the coralligenous assemblages is of fundamental importance in order to design appropriate monitoring programs and conservation policies, especially in the marine protected areas. For this purpose, benthic assemblages were studied in presence and absence of red gorgonians at two sites at the Tremiti islands. Overall, the benthic assemblages significantly differed among sites, nevertheless in both places, clear differences between assemblages associated and not associated to the gorgonian forests were found. In particular, encrusting corallinered algae were significantly more abundant in the gorgonian understories at both sites. This result indicates that the gorgonians may promote the development of calcareous algae, which are the main builders of the coralligenous habitats. Moreover species diversity resulted higher in the assemblages associated to the gorgonians. The present study highlights the role of Paramuricea clavata as a relevant ecosystem engineer in the coralligenous habitats.

Transform Tectonics and Non-Volcanic Oceanic Islands

Oceanic islands can be divided, according to their origin, in volcanic and tectonic. Volcanic islands are due to excess volcanism. Tectonic islands are mainly formed due to vertical tectonic motions of blocks of oceanic lithosphere along transverse ridges flanking transform faults at slow and ultraslow mid-ocean ridges. Vertical tectonic motions are due to a reorganization of the geometry of the transform plate boundary, with the transition from a transcurrent tectonics to a transtensive and/or transpressive tectonics, with the formation of the transverse ridges. Tectonic islands can be located also at the ridge–transform intersection: in this case the uplift is due by the movement of the long-lived detachment faults located along the flanks of the mid-ocean ridges. The "Vema" paleoisland (equatorial Atlantic) is at the summit of the southern transverse ridge of the Vema transform. It is now 450 m bsl and it is capped by a carbonate platform 500 m-thick, dated by 87Sr/86Sr at 10 Ma. Three tectonic paleoislands are on the summit of the transverse ridge flanking the Romanche megatrasform (equatorial Atlantic). They are now about 1,000 m bsl and they are formed by 300 m-thick carbonate platforms dated by 87Sr/86Sr, between 11 and 6 Ma. The tectonic paleoisland “Atlantis Bank" is located in the South-Western Indian Ridge, along the Atlantis II transform, and it is today 700 m bsl. The only modern example of oceanic tectonics island is the St. Paul Rocks (equatorial Atlantic), located along the St. Paul transform. This archipelago is the top of a peridotitic massif that it is now a left overstep undergoing transpression. Oceanic volcanic islands are characterized by rapid growth and subsequent thermal subsidence and drowning; in contrast, oceanic tectonic islands may have one or more stages of emersion related to vertical tectonic events along the large oceanic fracture zones.

Isolated Islands? Memory of the Holocaust in Formal and Non-Formal Education. The Case Study of Post-Communist Poland

Existing studies revealed several conflicts around the memory of the Holocaust in Poland: between understanding the need to teach about the Holocaust and indifference toward anti-Jewish graffiti; a conflict around the perception of Polish help to Jews; and the competing images of Polish and Jewish suffering during World War II. Those conflicts will be addressed in the paper as reflecting educational gaps in the Polish education system (lack of bad memory). This paper will look at the consciousness of young Poles, in terms of attitudes toward Jews, the Holocaust and memory of the Holocaust. The data presented are the preliminary results of the author’s longitudinal study „Attitudes of Young Poles toward the Jews and the Holocaust”. Quantitative and qualitative studies include field studies and participant observation of educational projects in Tykocin, Treblinka, Warsaw, Lublin, Bodzentyn and Kielce. The paper will present some components of the development of education about the Holocaust in Poland. There is a need to evaluate the attempt to bring back the memory of Jewish neighbours in some of the states of Central and Eastern Europe, a process with an ongoing effort to renovate monuments, destroyed cemeteries and synagogues. The number and scope of such initiatives in Poland indicate that civic institutions and individuals are intensifying their efforts to teach their fellow citizens about the Holocaust, however their impact should be assessed in detail.

Cryptic invertebrates on subtidal rocky reefs vary with microhabitat structure and protection from fishing

The deployment of flat concrete blocks on subtidal rocky reefs can replicate natural reef microhabitats and provides a means for standardized sampling of cryptic invertebrates. The shape of the cavity beneath the block is related to reef topography and may influence the invertebrate community by affecting the amount of space for cryptic fauna to colonise and influencing the effectiveness of their predator-defence mechanisms. To determine the effect of sub-block reef structure and different levels of external predators on cryptic molluscs and echinoderms, I deployed concrete blocks at locations inside and outside the Maria Island marine reserve in eastern Tasmania, Australia. Relationships between sub-block reef structure and the cryptic invertebrate assemblage were evident between locations, whereas only a small but significant proportion of variation of assemblages between blocks within location was explained by reef surface area. No clear association with external predation pressure was evident in multivariate analyses of variation in assemblage structure. Juvenile abalone Haliotis rubra were not influenced by micro-habitat structure but were significantly less abundant at protected locations, the only species to exhibit such a response. This result follows a decline of emergent adult abalone in the marine reserve and raises the possibility of recruitment failure of abalone at some fully protected locations in the longer term.

Terrestrial and submarine evidence for the extent and timing of the Last Glacial Maximum and the onset of deglaciation on the maritime-Antarctic and sub-Antarctic islands

This paper is the maritime and sub–Antarctic contribution to the Scientific Committee for Antarctic Research (SCAR) Past Antarctic Ice Sheet Dynamics (PAIS) community Antarctic Ice Sheet reconstruction. The overarching aim for all sectors of Antarctica was to reconstruct the Last Glacial Maximum (LGM) ice sheet extent and thickness, and map the subsequent deglaciation in a series of 5000 year time slices. However, our review of the literature found surprisingly few high quality chronological constraints on changing glacier extents on these timescales in the maritime and sub–Antarctic sector. Therefore, in this paper we focus on an assessment of the terrestrial and offshore evidence for the LGM ice extent, establishing minimum ages for the onset of deglaciation, and separating evidence of deglaciation from LGM limits from those associated with later Holocene glacier fluctuations. Evidence included geomorphological descriptions of glacial landscapes, radiocarbon dated basal peat and lake sediment deposits, cosmogenic isotope ages of glacial features and molecular biological data. We propose a classification of the glacial history of the maritime and sub–Antarctic islands based on this assembled evidence. These include: (Type I) islands which accumulated little or no LGM ice; (Type II) islands with a limited LGM ice extent but evidence of extensive earlier continental shelf glaciations; (Type III) seamounts and volcanoes unlikely to have accumulated significant LGM ice cover; (Type IV) islands on shallow shelves with both terrestrial and submarine evidence of LGM (and/or earlier) ice expansion; (Type V) Islands north of the Antarctic Polar Front with terrestrial evidence of LGM ice expansion; and (Type VI) islands with no data. Finally, we review the climatological and geomorphological settings that separate the glaciological history of the islands within this classification scheme.