The structure of planktonic communities under variable coastal upwelling conditions off Cape Ghir (31ºN), in the Canary Current System (NW Africa)

Universidad de Las Palmas de Gran Canaria. Facultad de Ciencias del Mar. Programa de doctorado en Oceanografía. Diploma de Estudios Avanzados

Assessment of the presence of pharmaceutical compounds in seawater samples from coastal area of Gran Canaria Island (Spain)

[EN]This study presents the evaluation of seven pharmaceutical compounds belonging to different commonly used therapeutic classes in seawater samples from coastal areas of Gran Canaria Island. The target compounds include atenolol (antihypertensive), acetaminophen (analgesic), norfloxacin and ciprofloxacin (antibiotics), carbamazepine (antiepileptic) and ketoprofen and diclofenac (anti-inflammatory). Solid phase extraction (SPE) was used for the extraction and preconcentration of the samples, and liquid chromatography tandem mass spectrometry (LC-MS/MS) was used for the determination of the compounds. Under optimal conditions, the recoveries obtained were in the range of 78.3% to 98.2%, and the relative standard deviations were less than 11.8%. The detection and quantification limits of the method were in the ranges of 0.1–2.8 and 0.3–9.3 ng·L−1, respectively. The developed method was applied to evaluate the presence of these pharmaceutical compounds in seawater from four outfalls in Gran Canaria Island (Spain) during one year. Ciprofloxacin and norfloxacin were found in a large number of samples in a concentration range of 9.0–3551.7 ng·L−1. Low levels of diclofenac, acetaminophen and ketoprofen were found sporadically.

Multi-parameter observations from coastal waters to the deepest trenche: challenges studying the carbón system with optode technology

[EN]This presentation will give examples on how multi-parameter platforms have been used in a variety of applications ranging from shallow coastal on-line observatories down to measuring in the deepest Ocean trenches. Focus will be on projects in which optode technology (primarily for CO2 and O2) has served to study different aspects of the carbon system including primary production/consumption, air-sea exchange, leakage detection from underwater storage of CO2 and measurements from moving platforms like gliders and ferries. The performance of recently developed pH optodes will als

Statistical assessment of annual patterns in coastal extreme wave conditions

[EN]The annual cycle in extreme values of significant wave height is examined by transforming the timing ofthe storm peaks in a circular variable, with the aim of taking advantage of the many tests devised to explore uniformity on the circle. The use of four different but complementary uniformity tests makes possible a robust assessment of the annual cycle statistical significance. Seasonality of storms in a long time series of significant wave heights, measured in a coastal zone, is examined. The presence of a seasonal pattem is statistically beyond doubt.

Two fluid numerical model for coastal applications

Wave breaking is an important coastal process, influencing hydro-morphodynamic processes such as turbulence generation and wave energy dissipation, run-up on the beach and overtopping of coastal defence structures. During breaking, waves are complex mixtures of air and water (“white water”) whose properties affect velocity and pressure fields in the vicinity of the free surface and, depending on the breaker characteristics, different mechanisms for air entrainment are usually observed. Several laboratory experiments have been performed to investigate the role of air bubbles in the wave breaking process (Chanson & Cummings, 1994, among others) and in wave loading on vertical wall (Oumeraci et al., 2001; Peregrine et al., 2006, among others), showing that the air phase is not negligible since the turbulent energy dissipation involves air-water mixture. The recent advancement of numerical models has given valuable insights in the knowledge of wave transformation and interaction with coastal structures. Among these models, some solve the RANS equations coupled with a free-surface tracking algorithm and describe velocity, pressure, turbulence and vorticity fields (Lara et al. 2006 a-b, Clementi et al., 2007). The single-phase numerical model, in which the constitutive equations are solved only for the liquid phase, neglects effects induced by air movement and trapped air bubbles in water. Numerical approximations at the free surface may induce errors in predicting breaking point and wave height and moreover, entrapped air bubbles and water splash in air are not properly represented. The aim of the present thesis is to develop a new two-phase model called COBRAS2 (stands for Cornell Breaking waves And Structures 2 phases), that is the enhancement of the single-phase code COBRAS0, originally developed at Cornell University (Lin & Liu, 1998). In the first part of the work, both fluids are considered as incompressible, while the second part will treat air compressibility modelling. The mathematical formulation and the numerical resolution of the governing equations of COBRAS2 are derived and some model-experiment comparisons are shown. In particular, validation tests are performed in order to prove model stability and accuracy. The simulation of the rising of a large air bubble in an otherwise quiescent water pool reveals the model capability to reproduce the process physics in a realistic way. Analytical solutions for stationary and internal waves are compared with corresponding numerical results, in order to test processes involving wide range of density difference. Waves induced by dam-break in different scenarios (on dry and wet beds, as well as on a ramp) are studied, focusing on the role of air as the medium in which the water wave propagates and on the numerical representation of bubble dynamics. Simulations of solitary and regular waves, characterized by both spilling and plunging breakers, are analyzed with comparisons with experimental data and other numerical model in order to investigate air influence on wave breaking mechanisms and underline model capability and accuracy. Finally, modelling of air compressibility is included in the new developed model and is validated, revealing an accurate reproduction of processes. Some preliminary tests on wave impact on vertical walls are performed: since air flow modelling allows to have a more realistic reproduction of breaking wave propagation, the dependence of wave breaker shapes and aeration characteristics on impact pressure values is studied and, on the basis of a qualitative comparison with experimental observations, the numerical simulations achieve good results.

The rupture process of recent tsunamigenic earthquakes by geophysical data inversion

Subduction zones are the favorite places to generate tsunamigenic earthquakes, where friction between oceanic and continental plates causes the occurrence of a strong seismicity. The topics and the methodologies discussed in this thesis are focussed to the understanding of the rupture process of the seismic sources of great earthquakes that generate tsunamis. The tsunamigenesis is controlled by several kinematical characteristic of the parent earthquake, as the focal mechanism, the depth of the rupture, the slip distribution along the fault area and by the mechanical properties of the source zone. Each of these factors plays a fundamental role in the tsunami generation. Therefore, inferring the source parameters of tsunamigenic earthquakes is crucial to understand the generation of the consequent tsunami and so to mitigate the risk along the coasts. The typical way to proceed when we want to gather information regarding the source process is to have recourse to the inversion of geophysical data that are available. Tsunami data, moreover, are useful to constrain the portion of the fault area that extends offshore, generally close to the trench that, on the contrary, other kinds of data are not able to constrain. In this thesis I have discussed the rupture process of some recent tsunamigenic events, as inferred by means of an inverse method. I have presented the 2003 Tokachi-Oki (Japan) earthquake (Mw 8.1). In this study the slip distribution on the fault has been inferred by inverting tsunami waveform, GPS, and bottom-pressure data. The joint inversion of tsunami and geodetic data has revealed a much better constrain for the slip distribution on the fault rather than the separate inversions of single datasets. Then we have studied the earthquake occurred on 2007 in southern Sumatra (Mw 8.4). By inverting several tsunami waveforms, both in the near and in the far field, we have determined the slip distribution and the mean rupture velocity along the causative fault. Since the largest patch of slip was concentrated on the deepest part of the fault, this is the likely reason for the small tsunami waves that followed the earthquake, pointing out how much the depth of the rupture plays a crucial role in controlling the tsunamigenesis. Finally, we have presented a new rupture model for the great 2004 Sumatra earthquake (Mw 9.2). We have performed the joint inversion of tsunami waveform, GPS and satellite altimetry data, to infer the slip distribution, the slip direction, and the rupture velocity on the fault. Furthermore, in this work we have presented a novel method to estimate, in a self-consistent way, the average rigidity of the source zone. The estimation of the source zone rigidity is important since it may play a significant role in the tsunami generation and, particularly for slow earthquakes, a low rigidity value is sometimes necessary to explain how a relatively low seismic moment earthquake may generate significant tsunamis; this latter point may be relevant for explaining the mechanics of the tsunami earthquakes, one of the open issues in present day seismology. The investigation of these tsunamigenic earthquakes has underlined the importance to use a joint inversion of different geophysical data to determine the rupture characteristics. The results shown here have important implications for the implementation of new tsunami warning systems – particularly in the near-field – the improvement of the current ones, and furthermore for the planning of the inundation maps for tsunami-hazard assessment along the coastal area.

Perceptual maps analysis for organic food consumers in China: a study on Shanghai consumers

Although in Europe and in the USA many studies focus on organic, little is known on the topic in China. This research provides an insight on Shanghai consumers’ perception of organic, aiming at understanding and representing in graphic form the network of mental associations that stems from the organic concept. To acquire, process and aggregate the individual networks it was used the “Brand concept mapping” methodology (Roedder et al., 2006), while the data analysis was carried out also using analytic procedures. The results achieved suggest that organic food is perceived as healthy, safe and costly. Although these attributes are pretty much consistent with the European perception, some relevant differences emerged. First, organic is not necessarily synonymous with natural product in China, also due to a poor translation of the term in the Chinese language that conveys the idea of a manufactured product. Secondly, the organic label has to deal with the competition with the green food label in terms of image and positioning on the market, since they are easily associated and often confused. “Environmental protection” also emerged as relevant association, while the ethical and social values were not mentioned. In conclusion, health care and security concerns are the factors that influence most the food consumption in China (many people are so concerned about food safety that they found it difficult to shop), and the associations “Safe”, “Pure and natural”, “without chemicals” and “healthy” have been identified as the best candidates for leveraging a sound image of organic food .

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.

Towards Rapid Environmental Assessment and Coastal Forecasting in the Northern Adriatic Sea

A new Coastal Rapid Environmental Assessment (CREA) strategy has been developed and successfully applied to the Northern Adriatic Sea. CREA strategy exploits the recent advent of operational oceanography to establish a CREA system based on an operational regional forecasting system and coastal monitoring networks of opportunity. The methodology wishes to initialize a coastal high resolution model, nested within the regional forecasting system, blending the large scale parent model fields with the available coastal observations to generate the requisite field estimates. CREA modeling system consists of a high resolution, O(800m), Adriatic SHELF model (ASHELF) implemented into the Northern Adriatic basin and nested within the Adriatic Forecasting System (AFS) (Oddo et al. 2006). The observational system is composed by the coastal networks established in the framework of ADRICOSM (ADRiatic sea integrated COastal areaS and river basin Managment system) Pilot Project. An assimilation technique exerts a correction of the initial field provided by AFS on the basis of the available observations. The blending of the two data sets has been carried out through a multi-scale optimal interpolation technique developed by Mariano and Brown (1992). Two CREA weekly exercises have been conducted: the first, at the beginning of May (spring experiment); the second in middle August (summer experiment). The weeks have been chosen looking at the availability of all coastal observations in the initialization day and one week later to validate model results, verifying our predictive skills. ASHELF spin up time has been investigated too, through a dedicated experiment, in order to obtain the maximum forecast accuracy within a minimum time. Energetic evaluations show that for the Northern Adriatic Sea and for the forcing applied, a spin-up period of one week allows ASHELF to generate new circulation features enabled by the increased resolution and its total kinetic energy to establish a new dynamical balance. CREA results, evaluated by mean of standard statistics between ASHELF and coastal CTDs, show improvement deriving from the initialization technique and a good model performance in the coastal areas of the Northern Adriatic basin, characterized by a shallow and wide continental shelf subject to substantial freshwater influence from rivers. Results demonstrate the feasibility of our CREA strategy to support coastal zone management and wish an additional establishment of operational coastal monitoring activities to advance it.

El Niño southern oscillation and its effect on fog oases along the Peruvian and Chilean coastal deserts

Fog oases, locally named Lomas, are distributed in a fragmented way along the western coast of Chile and Peru (South America) between ~6°S and 30°S following an altitudinal gradient determined by a fog layer. This fragmentation has been attributed to the hyper aridity of the desert. However, periodically climatic events influence the ‘normal seasonality’ of this ecosystem through a higher than average water input that triggers plant responses (e.g. primary productivity and phenology). The impact of the climatic oscillation may vary according to the season (wet/dry). This thesis evaluates the potential effect of climate oscillations, such as El Niño Southern Oscillation (ENSO), through the analysis of vegetation of this ecosystem following different approaches: Chapters two and three show the analysis of fog oasis along the Peruvian and Chilean deserts. The objectives are: 1) to explain the floristic connection of fog oases analysing their taxa composition differences and the phylogenetic affinities among them, 2) to explore the climate variables related to ENSO which likely affect fog production, and the responses of Lomas vegetation (composition, productivity, distribution) to climate patterns during ENSO events. Chapters four and five describe a fog-oasis in southern Peru during the 2008-2010 period. The objectives are: 3) to describe and create a new vegetation map of the Lomas vegetation using remote sensing analysis supported by field survey data, and 4) to identify the vegetation change during the dry season. The first part of our results show that: 1) there are three significantly different groups of Lomas (Northern Peru, Southern Peru, and Chile) with a significant phylogenetic divergence among them. The species composition reveals a latitudinal gradient of plant assemblages. The species origin, growth-forms typologies, and geographic position also reinforce the differences among groups. 2) Contradictory results have emerged from studies of low-cloud anomalies and the fog-collection during El Niño (EN). EN increases water availability in fog oases when fog should be less frequent due to the reduction of low-clouds amount and stratocumulus. Because a minor role of fog during EN is expected, it is likely that measurements of fog-water collection during EN are considering drizzle and fog at the same time. Although recent studies on fog oases have shown some relationship with the ENSO, responses of vegetation have been largely based on descriptive data, the absence of large temporal records limit the establishment of a direct relationship with climatic oscillations. The second part of the results show that: 3) five different classes of different spectral values correspond to the main land cover of Lomas using a Vegetation Index (VI). The study case is characterised by shrubs and trees with variable cover (dense, semi-dense and open). A secondary area is covered by small shrubs where the dominant tree species is not present. The cacti area and the old terraces with open vegetation were not identified with the VI. Agriculture is present in the area. Finally, 4) contrary to the dry season of 2008 and 2009 years, a higher VI was obtained during the dry season of 2010. The VI increased up to three times their average value, showing a clear spectral signal change, which coincided with the ENSO event of that period.

Climate impact studies of sediment transport on the Adriatic coastal zone

The study of the impact of climate change on the environment has been based, until very recently, on an global approach, whose interest from a local point of view is very limited. This thesis, on the contrary, has treated the study of the impact of climate change in the Adriatic Sea basin following a twofold strategy of regionalization and integration of numerical models in order to reproduce the present and future scenarios of the system through a more and more realistic and solid approach. In particular the focus of the study was on the impact on the physical environment and on the sediment transport in the basin. This latter is a very new and original issue, to our knowledge still uninvestigated. The study case of the coastal area of Montenegro was particularly studied, since it is characterized by an important supply of sediment through the Buna/Bojana river, second most important in the Adriatic basin in terms of flow. To do this, a methodology to introduce the tidal processes in a baroclinic primitive equations Ocean General Circulation Model was applied and tidal processes were successfully reproduced in the Adriatic Sea, analyzing also the impacts they have on the mean general circulation, on salt and heat transport and on mixing and stratification of the water column in the different seasons of the year. The new hydrodynamical model has been further coupled with a wave model and with a river and sea sediment transport model, showing good results in the reproduction of sediment transport processes. Finally this complex coupled platform was integrated in the period 2001-2030 under the A1B scenario of IPCC, and the impact of climate change on the physical system and on sediment transport was preliminarily evaluated.

Molecular phylogeography of the European coastal plants Crithmum maritimum L., Halimione portulacoides (L.) Aellen, Salsola kali L. and Calystegia soldanella (L.) R. Br.

The intraspecific phylogeography of four European coastal plants, Crithmum maritimum, Halimione portulacoides, Salsola kali and Calystegia soldanella, was inferred from AFLP and ITS data. Only in C. maritimum, H. portulacoides and S. kali, a spatial genetic structure was revealed. The phylogeographic similarities and dissimilarities of these species include: (1) All three have distinct Black/Aegean and Adriatic Sea clusters. (2) Salsola kali and H. portulacoides show a distinct Atlantic/North Sea/Baltic Sea cluster, while Atlantic and eastern Spanish material of C. maritimum clustered together. (3) In the west Mediterranean, only S. kali forms a single cluster, while both H. portulacoides and C. maritimum display a phylogeographic break in the vicinity of the southern French coast. For S. kali, AFLP and ITS data concur in identifying separate Atlantic, east and west Mediterranean clades. All these patterns are postulated to result from both temperature changes during the last glacial and contemporary sea currents. No geographic AFLP structure was revealed in C. soldanella, both at the range-wide and population level. This was attributed to the remarkable seed dispersal ability of this species and possibly its longevity and clonal growth, preserving a random pattern of genetic variation generated by long-distance seed dispersal over long time periods.