Estudio de la mesofauna en fondos arenosos y de "Halimeda incrassata" (Chlorophyta, Bryopsidales) del Cap Enderrocat, Mallorca

[Resumen:] Las especies invasoras pueden tener graves efectos negativos sobre los ecosistemas, siendo la segunda causa de pérdida de biodiversidad a nivel mundial. El mar Mediterráneo es uno de los mares más afectado por la invasión de especies foráneas debido a sus comunicaciones con el Atlántico mediante el estrecho de Gibraltar y con el mar Rojo mediante el canal de Suez y al intenso tráfico marítimo que en sus aguas ocurre. Una de las especies invasoras es el alga Halimeda incrassata que fue por primera vez localizada en el Mediterráneo (en aguas de Baleares) en 2011, es un alga de origen tropical que podría haber sido introducida mediante su uso en acuariofilia, turismo náutico o transporte marino. El área marina protegida de la Bahía de Palma en concreto el Cap Enderrocat ha sufrido una gran proliferación de esta alga en sus arenales desde su detección en 2011 y el objetivo de este trabajo es estudiar las comunidades de invertebrados que en esta localidad habitan, y testar un nuevo método de muestreo para epifauna. Para ello, se diseñó un experimento en el que se capturaron macroinvertebrados en 3 hábitats diferentes: banco de arena, pradera de Halimeda incrassata y pradera mixta de Cymodocea nodosa con Halimeda incrassata, mediante tres métodos diferentes. Los resultados muestran que la abundancia de los taxones estudiados es mayor tanto en la pradera mixta como en la de la Halimeda incrassata y por lo tanto se puede decir que la invasión tiene un efecto positivo para la abundancia de los siguientes grupos: Amphipoda, Isópoda, Cumacea, Mysidacea, Natantia, larvas Zoea y Ostracoda. Es decir, la invasión de H. incrassata en esta zona ha podido provocar un aumento de la biomasa de estos grupos de mesofauna, presas potenciales de peces que habitan en la zona como salmonetes pageles y raones, pudiendo provocar un efecto positivo para dichas especies. Al crear un nuevo hábitat antes inexistente (sobre fondo de arena), esta especie contribuye a escala local al aumento de la diversidad y biomasa de invertebrados. Sin embargo, al ser este un primer trabajo realizado debe complementarse en el futuro aumentando la escala espacial del estudio, incorporando el estudio de cambios temporales (tanto asociados a la estacionalidad de la planta como a su posible expansión e incremento de abundancia). Además, han de tenerse en cuenta las interacciones con otras especies en la zona y para ello se ha de seguir estudiando la evolución del macrófito y de las comunidades faunísticas asociadas así como sus interacciones con otros macrófitos o ingenieros ecosistémicos ya presentes en la zona como P. oceanica o C. nodosa.[Abstract:] Invasive species can have serious negative effects on ecosystems, being the second leading cause of biodiversity loss worldwide. The Mediterranean Sea is one of the most affected seas by the invasion of alien species due to the communications with the Atlantic by the Strait of Gibraltar, the Red Sea by the Suez cannel and the long history of boating. One of invasive species is Halimeda incrassata which was first reported in the Mediterranean (Balearic waters) in 2011. This is a tropical alga which was likely introduced via the aquarium trade or marine transport. The marine protected area of the bay of Palma, specifically Cap Enderrocat has suffered a great proliferation of this alga and the main objective of this work is to examine the invertebrates communities in this area and assess different sampling methodologies. A comparative sampling approached was designed to capture macroinvertebrates from 3 different habitats: sandy bottom, Halimeda incrassata beds and beds of Cymodocea nodosa mixed with Halimeda incrassata using three diferent methods. The results show that the abundance of the studied taxa is greater in the mixed habitat and in the one of the Halimeda incrassata and therefore it can be said that the invasion has a positive effect for the abundance of the following groups: Amphipoda, Isópoda, Cumacea, Mysidacea, Natantia, Zoea and Ostracoda larvae. That allows to say that the invasion of H. incrassata has been able to promote an increase of the biomass of these groups of mesofauna, potential prey of fish that inhabit the area as razor fish and another labrids, being able to provoke a positive effect for these species. By creating a new habitat previously non-existent (on sandy bottom), this invasive species contributes locally to increased diversity and biomass of invertebrates. However, since this is a first work done, it should be complemented in the future by increasing the spatial scale of the study, incorporating the study of temporal changes (both associated to plant and plant seasonality and the possible expansion and increase of H. incrassata). It is necessary to continue studying the evolution of this invasive macrophyte and associated faunal communities as well as its interactions with other macrophytes or ecosystemic engineers already present in the area such as P. oceanica or C. nodosa.Traballo fin de mestrado (UDC.CIE). Bioloxía mariña. Curso 2016/201

Fórmulas de cuadratura invariantes de grados 6 y 7 para el simplex 4-dimensional

Para un simplex 4-dimensional T4 se conocen fórmulas de cuadratura invariantes de grado de precisión hasta d = 5 como se muestra en1. En este trabajo presentamos dos nuevas fórmulas de cuadratura invariantes de grado de precisión d = 6 con 41 y 45 nodos respectivamente y una nueva fórmula de cuadratura invariante de grado d = 7 con 56 nodos. Estas fórmulas han sido obtenidas usando la teoría de consistencia desarrollada en3 y las estructuras consistentes dadas en2.Invariant quadrature rules for the Cdimensional simplex T4 are known for degrees of precission up to d = 5 as shown inl. In this paper we present two new invariant quadrature rules of degree of precission d = 6 with 41 and 45 nodes respectively and a new invariant quadrature rule of degree d = 7 with 56 nodes. These rules have been obtained using the consistency theory developed in3 and the consistent structures given in2Peer Reviewe

Sediment-effects on seagrass Zostera muelleri in New Zealand

Seagrasses are ecosystem engineers that provide important ecological functions and societal economic values. Examples of the services that seagrasses provide are: sediment and coastal stability; maintenance of water quality; primary productivity for coastal ecosystems; fisheries nursery habitat; food for large herbivores; food-webs for complex marine communities; fisheries habitats; and carbon sink. They help minimise the costs of foreshore protection and maintain and support both tourism and fisheries economies. Different factors are implicated in causing the decline of seagrass ecosystems, but human activities are clearly identified as one of the major causes of seagrass decline in the world. Humans affect this ecosystem via physical damage (e.g., harbour developments, trawling, aquaculture), introduced species, global change, and pollution (e.g., sediments, nutrients, wastewaters, herbicides, heavy metals, petrochemicals). In New Zealand, sediment is the most pervasive seagrass stressor and the most prominent cause of seagrass decline. The goal of this PhD was to determine sediment effects on the seagrass Zostera muelleri in terms of light attenuation and substrate physico-chemical alteration. Within this research framework, provision of assistance for successful seagrass restoration was also considered. The principal research question for this project was to evaluate how sediment affects seagrasses and the project hypothesis was that sedimentation affects seagrass by altering the light climate, physically smothering the plants and modifying substrate physico-chemical composition. An extensive global literature review was undertaken to improve understanding of the international body of knowledge on the effects of sediment upon seagrass. Field surveys, field experiments and mesocosm experiments were used to evaluate the research objective. Field experiments were undertaken in Pāuatahanui Inlet, New Zealand. This inlet provides a wide range of seagrass cover, historical seagrass sites and substrate conditions, which makes it an excellent field laboratory to test hypotheses. Mesocosm experiments were undertaken at the University of Waikato Marine Field Station in Tauranga. A series of observations and experiments investigated the relationship between Z. muelleri growth, light climate and substrate properties. Initially, correlations between receiving irradiance, substrate physicochemical variables and Z. muelleri traits in Pāuatahanui Inlet, were explored using an observational seasonal survey. A series of experiments followed, that used field and mesocosm-based methods that allowed deeper analysis of how sediment affects light climate and substrate properties at seagrass habitats. These results provided new insights into conditions under which seagrass declines or is unable to re-establish. The observational-based field study was undertaken in three habitat types: historical seagrass habitat, existing seagrass habitat and potential seagrass habitat and involved two field campaigns in winter and summer. A variety of substrate physicochemical variables including substrate grain size, bulk density, redox profiles, porewater nutrients, dissolved metals, receiving irradiance and temperature were measured as well as Z. muelleri traits such as percent plant cover, rhizome length, shoot density leaf width and length. Significant differences of substrate properties were observed between deteriorated historical habitat substrate and existing seagrass habitats and potential seagrass habitats. Increased substrate muddiness and consequent unfavorable rhizosphere conditions were implicated as causes of seagrass decline or failure to recolonize historical habitat. The results suggested for the multi-stressor effects of sediment on seagrasses, with both substrate suitability and submerged light climate for seagrass being detrimentally affected. However, despite considering a wide range of substrate properties and irradiance, the exact mechanisms of seagrass decline could not be extracted from the data collected in the observational field survey. Further manipulative mesocosm experimentation was expected to allow more conclusive inferences to be drawn on the influence of substrate physicochemical factors and irradiance on seagrass growth and persistence. A factorial mesocosm experiment was conducted to elucidate the links between these. Two irradiance treatments; low (6.3 mol m⁻² d⁻¹) and very low (2.3 mol m⁻² d⁻¹), were crossed with two substrate treatments; historical substrate (42 % mud) and existing substrate (20 % mud). Seagrass growth was monitored for six weeks. Belowground biomass and rhizome growth were significantly reduced by substrate muddiness but were unaffected by irradiance. However, shoot growth was significantly affected by reduced irradiance and increased substrate muddiness as well as the synergistic interaction between both these parameters. Results suggest that Z. muelleri inhabiting muddy substrates has an increased irradiance demand to deal with adverse rhizosphere conditions and specifically to oxygenate the rhizosphere. Therefore, interactions between substrate and light climate, which are both affected by fine sediment pollution, should be considered when determining light thresholds for seagrass survival. In order to further investigate the effects of site and irradiance on seagrass, a field transplanting experiment was undertaken across the previously characterised habitats in the Pāuatahanui Inlet. The aim of this experiment was to disentangle substrate effects from other effects such as light climate and smothering. As the experiment progressed, some challenges to its successful completion emerged. Firstly, it proved impossible to reliably relocate some of the transplanted sprigs, which impeded the planned comparisons. Secondly, an incursion of the filamentous green algae Chaetomorpha ligustica smothered approximately half of the quadrats of one of the treatments. This is the first time, negative impacts of this species upon meadows of the New Zealand seagrass Zostera muelleri has been reported. Chaetomorpha ligustica can easily be misidentified in the field and genetic tests are required to identify this species. Hence, the need for careful identification of this green macroalga blooms in future as well as further research on growth requirements and origins of strains is desirable as it may play an important role on seagrass loss. Outcomes from this transplanting experiment allowed the conclusion to be drawn that the cumulative effect of rhizosphere deterioration, lower irradiance and close location to a source of natural sediment input during events such as storms may be the cause of the inability of seagrass to re-establish at Pāuatahanui Inlet in historical seagrass habitat. The last experiment of the project aimed to compare the ability of the seagrass to carry out photosynthesis both in air and in water as this is potentially important for determining its vulnerability to enhanced water turbidity. To compare photosynthetic rates, oxygen (O₂) flux in water, CO₂ flux in air, and pulse amplitude modulated (PAM) fluorometry in both air and water were utilized. In water, “gross” photosynthetic O₂ evolution (GPS) as oxygen exchange averaged 2.24 μmol O₂ m⁻²s⁻¹, leaf respiration rates averaged 0.44 μmol O₂ m⁻²s⁻¹ and saturation irradiance 115 μmol photons m⁻²s⁻¹. In air, CO₂ showed light saturated gross photosynthesis of 2.26 μmol CO₂ m⁻²s⁻¹, respiration rates of 0.7 μmol CO₂ m⁻²s⁻¹ and saturating irradiance 286 μmol photon m⁻²s⁻¹. Compensation irradiance (Ec) is 22 μmol photons m⁻²s⁻¹ and 140 μmol photons m⁻²s⁻¹ when submerge and emerge showing higher photorespiration when emerged. Potential production of intertidal seagrass under submerged and emerged conditions was modeled across tidal cycles using experimental gas exchange results and field measured irradiance, using two scenarios; a high tide scenario 1 when high tide coincided with midday and low tide scenario 2 when low tide did. Respiration rate differed little between scenarios, and approximately similar amounts of net photosynthesis were predicted for emerged and submerged periods. In contrast emerged net photosynthesis was 25 times greater than submerged in the low tide scenario. These results support previous studies that have reported emerged photosynthesis as a mechanism to mitigate degraded submerged light climate, and to contribute to seagrass production estimates. Lastly, a synthesis of new knowledge gained through this thesis, together with recently published literature is presented, which develops a new paradigm for understanding the interactive and cumulative effects of sediment on seagrass. Of particular importance are the complex interactions between irradiance and substrate muddification. This research suggests that a nuanced interpretation of fine sediment effects on seagrass, growth and persistence needs to be developed that is sensitive to the specific estuary exposure to the pollutant. Future directions for research are also suggested, which aim to build upon the research presented in this thesis and further advance understanding of the physicochemical drivers of seagrass Zostera muelleri loss. The information gathered from the research is available to help new methods of seagrass restoration development. This research provided evidence that enriches our knowledge of seagrass, especially estuarine seagrass ecosystems in New Zealand and this will provide an opportunity to create tools for better management of water quality and quantity targets within New Zealand to help maintain and hopefully restore this important ecosystem

Desarrollo sostenible y responsabilidad social corporativa: su tratamiento en los grados de economía y administración y dirección de empresas

Due to the social and environmental problems associated to the economic growth concepts such as Corporate Social Responsibility and Sustainable Development are now part of the discourse of the business community. Many leading Companies are now seeing CSR and SD practices, not as a necessary cost, but as a strategy that allows them to increase their profits. However, this is not the case of the most of the firms. Therefore, it seems that it is necessary to make future managers aware of how they can carry out the virtuous circles between being responsible and profitable and the universities have an important role to play in this endeavor. Accordingly, the objective of this work is to find out to what extent a particular university educates in social and environmental values. After the analysis of the Universidad Pública de Navarra and the degree in Business Administration and Management we can conclude that this University is not meeting that important roleGraduado o Graduada en Administración y Dirección de Empresas por la Universidad Pública de NavarraEnpresen Administrazio eta Zuzendaritzan Graduatua Nafarroako Unibertsitate Publikoa