41 research outputs found

    Estuarine Mapping and Eco-Geomorphological Characterization for Potential Application in Conservation and Management: Three Study Cases along the Iberian Coast

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    Geomorphological changes in recent decades in three estuaries along the Iberian coast were analysed using aerial orthophotographs. A hierarchical classification scheme, based on a literature review representing 26 estuarine eco-geomorphological features relevant to estuarine dynamics and functioning, is described. The estuaries selected were San Vicente de la Barquera (N Spain), Guadiana River (SW border between Spain and Portugal) and the Ebro River Delta mouth (NE Spain). For these systems, a 60-year time series of high-resolution maps was developed, analysing the changes in feature surfaces. The main subsystems analysed were beach, dunes, saltmarshes and the drainage network. The results of the cartographies showed general behaviour common to all transitional systems, relationships among main subsystems and processes inherent to each one. This work illustrates how beaches and dunes serve as a protective barrier for the tidal flats, acting as a sediment buffer for the entire system. The subsystems are connected by the drainage network responsible for the exchange of matter and energy between them. Furthermore, an accuracy assessment was performed in one of the study zones to identify the limitations of mapping with aerial photographs. The results explain the changes with time but also the processes and relationships between the estuarine features at a long-term scale. This work adds an important perspective towards a general understanding of their dependence on intrinsic and boundary conditions

    Evaluating the Performance of High Spatial Resolution UAV-Photogrammetry and UAV-LiDAR for Salt Marshes: The Cadiz Bay Study Case

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    Salt marshes are very valuable and threatened ecosystems, and are challenging to study due to their difficulty of access and the alterable nature of their soft soil. Remote sensing methods in unmanned aerial vehicles (UAVs) offer a great opportunity to improve our knowledge in this type of complex habitat. However, further analysis of UAV technology performance is still required to standardize the application of these methods in salt marshes. This work evaluates and tunes UAV-photogrammetry and UAV-LiDAR techniques for high-resolution applications in salt marsh habitats, and also analyzes the best sensor configuration to collect reliable data and generate the best results. The performance is evaluated through the accuracy assessment of the corresponding generated products. UAV-photogrammetry yields the highest spatial resolution (1.25 cm/pixel) orthomosaics and digital models, but at the cost of large files that require long processing times, making it applicable only for small areas. On the other hand, UAV-LiDAR has proven to be a promising tool for coastal research, providing high-resolution orthomosaics (2.7 cm/pixel) and high-accuracy digital elevation models from lighter datasets, with less time required to process them. One issue with UAV-LiDAR application in salt marshes is the limited effectiveness of the autoclassification of bare ground and vegetated surfaces, since the scattering of the LiDAR point clouds for both salt marsh surfaces is similar. Fortunately, when LiDAR and multispectral data are combined, the efficiency of this step improves significantly. The correlation between LiDAR measurements and field values improves from R2 values of 0.79 to 0.94 when stable reference points (i.e., a few additional GCPs in rigid infrastructures) are also included as control points. According to our results, the most reliable LiDAR sensor configuration for salt marsh applications is the nadir non-repetitive combination. This configuration has the best balance between dataset size, spatial resolution, and processing time. Nevertheless, further research is still needed to develop accurate canopy height models. The present work demonstrates that UAV-LiDAR technology offers a suitable solution for coastal research applications where high spatial and temporal resolutions are required

    Coastal macrophytes contribute to the long term geomorphological stability of Cadiz Bay

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    Charla presentada en el 2015 Aquatic Sciences Meeting. Aquatic Sciences: Global And Regional Perspectives — North Meets South (http://sgmeet.com/aslo/granada2015)In the Eastern Gulf of Cadiz, terrestrial sediments are mainly supplied by the large Guadalquivir and smaller Guadalete rivers, both of which are subject to substantial man-made interventions. These rivers are the main sediment source to Cadiz Bay; a shallow, meso-tidal bay with high subtidal macrophyte coverage and extensive salt marshes that appears to act as an effective filter, retaining fine material and ensuring accretion rates that match sea-level rise. Field observations suggest that the relative importance of the different mechanisms by which macrophyte canopies promote accretion is related to their species-specific biometric properties and zonation. Overall, we argue that the key mechanism which enhances long-term accretion in the bay is related to the reduction of erosive forces on the sediment bed cause by the interaction of plant canopies with local hydrodynamics, particularly during high wind events. Considering the importance of coastal macrophytes for long-term accretion, we briefly discuss how different local and regional management strategies in relation to IPCC climate change predictions may influence terrestrial derived-sediment dynamics.EU FP7-SPACE-2013: FAST - GA n.607131, Junta Andalucia: P07-RNM-2516, P09-RNM-4853, PR11-RNM-7722,MECD: CTM2008-00012/MAR, Schure-Beijerinck-Popping Fund: SBP/JK/2007-32), E.U. MarinERA Project MedEX: CTM2008-04036-E/MAR) y PERSEUS (FP7-287600)Charla en formato pd

    Interaction between hydrodynamics and seagrass canopy structure: Spatially explicit effects on ammonium uptake rates

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    The hypotheses that (1) different seagrass morphologies may facilitate different nutrient uptake rates under similar hydrodynamic forcing and (2) this effect on nutrient uptake rates is spatially explicit, with the highest uptake rates at edges of patches, where currents and turbulence are highest, were examined under unidirectional flow conditions.We thank Jos van Soelen, Bas Koutstaal, and Louie Haazen for invaluable technical assistance. In addition, we are grateful to Britta Gribsholt, Bart Veuger, Miguel Bernal, Juan Jose Vergara, and Alfredo Izquirdo for helpful discussion. In addition, we thank Josef D. Ackerman and the anonymous reviewers for comments that greatly improved the manuscript. This work and the first author were supported by an EU Marie Curie host fellowship for transfer of knowledge, MTKD-CT-2004-509254, and the Spanish national project EVAMARIA, CTM2005-00395/MAR. F.G.B. holds an EU Marie Curie individual fellowship, MEIF-CT-2005-515071. This is publication 4251 of the Netherlands Institute of Ecology (NIOO-KNAW)

    Potential uptake of dissolved organic matter by seagrasses and macroalgae

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    Dissolved organic nitrogen (DON) acts as a large reservoir of fixed nitrogen. Whereas DON utilization is common in the microbial community, little is known about utilization by macrophytes. We investigated the ability of the coexisting temperate marine macrophytes Zostera noltii, Cymodocea nodosa, and Caulerpa prolifera to take up nitrogen and carbon from small organic substrates of different molecular complexities (urea, glycine, L-leucine, and L-phenylalanine) and from dissolved organic matter (DOM) derived from algal and bacterial cultures (substrates with a complex composition). In addition to inorganic nitrogen, nitrogen from small organic substrates could be taken up in significant amounts by all macrophytes. Substrate uptake by the aboveground tissue differed from that of the belowground tissue. No relationships between carbon and nitrogen uptake of small organics were found. The preference for individual organic substrates was related to their structural complexity and C:N ratio. Uptake of algae-derived organic nitrogen was of similar magnitude as inorganic nitrogen, and was preferred over bacteria-derived nitrogen. These results add to the growing evidence that direct or quick indirect DON utilization may be more widespread among aquatic macrophytes than traditionally thought.This research was supported by the regional government of Andalusia project FUNDIV (P07-RNM-2516), the Spanish Project CTM2008-00012/MAR, a European Reintegration Grant (MERG-CT-2007-205675), a travel grant from Schure-Beijerinck-Popping Fund (SBP/JK/2007-32) and the Netherlands Organization for Scientific Research. Thanks to Fidel Echevarrìa Navas (Director of CACYTMAR) for granting us access to facilities, and to Bas Koutstaal for helping with sample processing. We also thank the anonymous reviewers for their valuable comments which significantly improved this manuscript

    Percepção do bem-estar espiritual nos estudantes de enfermagem

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    Introducción: Conocer las percepciones del Bienestar Espiritual en los estudiantes de Enfermería responde a la necesidad hacer visible los valores del cuidado humano desde el proceso de formación universitaria. Objetivo: Determinar el bienestar espiritual percibido por los estudiantes de la Facultad de Enfermería de la Universidad Nacional de San Agustín en Perú (Arequipa). Método: Estudio descriptivo de abordaje cuantitativo, en el que participaron 198 estudiantes de enfermería que cursaban prácticas de pregrado. Se utilizó el instrumento SHALOM, a partir de la propuesta de Fisher, y una ficha de caracterización. El análisis se realizó mediante estadística descriptiva con medidas de tendencia central y de dispersión e inferencial mediante comparación con pruebas no paramétricas. Resultados: los estudiantes en su mayoría del género femenino, estado civil soltero, con promedio de edad de 20,4 años, y predominio de formación por competencias presentan moderados niveles de bienestar espiritual en la categoría ideal para la salud espiritual, seguido por la de ayuda espiritual y la de cómo usted se siente. Se identifica además, diferencias significativas en la percepción que tiene el estudiante frente a las tres categorías y en los dominios personal, ambiental, comunal y trascendental. Conclusiones: Es determinante incluir el componente de espiritualidad y cuidado espiritual como elementos integradores a lo largo de la formación de enfermería. Se requiere fomentar una práctica de bienestar espiritual como elemento central del cuidado de enfermeríaBackground: To know nursing students’ perception of spiritual well-being respond to the need of make human care values visible, during the process of university training. Objective: To determine the participants’ perceptions about spiritual well-being in a sample of students from the Faculty of nursing from Universidad Nacional de San Agustín (Arequipa, Perú) Methods: Descriptive quantitative study with a sample of 198 nursing students, who were doing clinical practice as part of their undergraduate training. The SHALOM instrument was used, accordingly with John Fisher’s propositions, as well as characterization slip. The analysis was conducted by using descriptive, central tendency and dispersion statistics, as well as non-parametric tests for inferential analysis. Results: the majority of students were female, single marital status, with an average age of 20.4 years. Competency-based training predominated and moderate levels of spiritual well-being were observed on each of the following categories: spiritual health ideal, spiritual help and “how do you feel”. Furthermore, statistically significant differences were observed between student’s perception of each of the abovementioned categories in the personal, environmental, communal and transcendental domains. Conclusions: It is determinant to include spiritual component and spiritual caring as integrative elements throughout nursery school training. It highlights the need of promoting a spiritual well-being practice as the central element in nursing care.Introdução: Conhecer as percepções do bem-estar espiritual nos estudantes de Enfermagem responde à necessidade de tornar visíveis os valores dos cuidados humanos a partir do processo de formação universitária. Objectivo: Determinar o bem-estar espiritual percebido pelos estudantes da Faculdade de Enfermagem da Universidade Nacional de San Agustin no Peru (Arequipa). Método: Estudo descritivo da abordagem quantitativa, no qual participaram 198 estudantes de enfermagem que eram estudantes de graduação. O instrumento SHALOM, baseado na proposta de Fisher, e uma forma de caracterização foram utilizados. A análise foi realizada através da estatística descritiva com medidas de tendência central e de dispersão e inferencial através da comparação com testes não paramétricos. Resultados: os estudantes, na sua maioria do sexo feminino, solteiros, com uma idade média de 20,4 anos, e predominância da formação por competências apresentam níveis moderados de bem-estar espiritual na categoria ideal para a saúde espiritual, seguidos de ajuda espiritual e como se sente. São também identificadas, diferenças significativas na percepção que o estudante tem perante as três categorias e nos domínios pessoal, ambiental, comunitário e transcendental. Conclusões: É determinante incluir a componente de espiritualidade e cuidados espirituais como elementos integradores ao longo da educação de enfermagem. É necessário promover uma prática de bem-estar espiritual como elemento central dos cuidados de enfermagem

    Sedimentary Organic Carbon and Nitrogen Sequestration Across a Vertical Gradient on a Temperate Wetland Seascape Including Salt Marshes, Seagrass Meadows and Rhizophytic Macroalgae Beds

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    Correction to: Ecosystems https://doi.org/10.1007/s10021-022-00801-5 Correction Published: 10 March 2023Coastal wetlands are key in regulating coastal carbon and nitrogen dynamics and contribute significantly to climate change mitigation and anthropogenic nutrient reduction. We investigated organic carbon (OC) and total nitrogen (TN) stocks and burial rates at four adjacent vegetated coastal habitats across the seascape elevation gradient of Cádiz Bay (South Spain), including one species of salt marsh, two of seagrasses, and a macroalgae. OC and TN stocks in the upper 1 m sediment layer were higher at the subtidal seagrass Cymodocea nodosa (72.3 Mg OC ha−1, 8.6 Mg TN ha−1) followed by the upper intertidal salt marsh Sporobolus maritimus (66.5 Mg OC ha−1, 5.9 Mg TN ha−1), the subtidal rhizophytic macroalgae Caulerpa prolifera (62.2 Mg OC ha−1, 7.2 Mg TN ha−1), and the lower intertidal seagrass Zostera noltei (52.8 Mg OC ha−1, 5.2 Mg TN ha−1). The sedimentation rates increased from lower to higher elevation, from the intertidal salt marsh (0.24 g cm−2 y−1) to the subtidal macroalgae (0.12 g cm−2 y−1). The organic carbon burial rate was highest at the intertidal salt marsh (91 ± 31 g OC m−2 y−1), followed by the intertidal seagrass, (44 ± 15 g OC m−2 y−1), the subtidal seagrass (39 ± 6 g OC m−2 y−1), and the subtidal macroalgae (28 ± 4 g OC m−2 y−1). Total nitrogen burial rates were similar among the three lower vegetation types, ranging from 5 ± 2 to 3 ± 1 g TN m−2 y−1, and peaked at S. maritimus salt marsh with 7 ± 1 g TN m−2 y−1. The contribution of allochthonous sources to the sedimentary organic matter decreased with elevation, from 72% in C. prolifera to 33% at S. maritimus. Our results highlight the need of using habitat-specific OC and TN stocks and burial rates to improve our ability to predict OC and TN sequestration capacity of vegetated coastal habitats at the seascape level. We also demonstrated that the stocks and burial rates in C. prolifera habitats were within the range of well-accepted blue carbon ecosystems such as seagrass meadows and salt marshes.17 página

    Foreshore Assessment using Space Technology

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    Poster presented in SENTINEL-2 for Science Workshop (ESA-ESRIN, Frascati, Italy) on the 20th, 21st and 22nd May 2014. See more information about this workshop in http://seom.esa.int/S2forScience2014FORESHORE ASSESSMENT USING SPACE TECHNOLOGY. Vegetated foreshores and floodplains provide important ecosystem services. These include benefits for coastal defence: the foreshores attenuate waves, enhance sedimentation and reduce erosion, mitigating flood risk. At present, this function of wetland ecosystems is hardly incorporated in coastal defence schemes. Yet considering foreshores and floodplains in water safety assessments and in levee design can result in considerable cost reductions for flood risk management. In the EU-funded project FAST (Foreshore Assessment using Space Technology, 2014-2018), we aim to develop a GMES/Copernicus downstream service, combining Sentinel satellite data and in situ data to integrate the functioning of wetlands in flood risk management strategies. Sentinel data will be used to retrieve relevant biophysical parameters to characterise the foreshore, such as the morphology/topography of the foreshores, the density/biomass and type of vegetation, and the sediment type. Because of their location at the dynamic interface of land and water, foreshores and floodplains pose particular challenges for satellite observation and analysis, both regarding spatial and spectral resolution (due to the large environmental gradients and heterogeneity) and regarding temporal resolution (due to the large temporal variation as a result of, for example, tidal inundation). Information on some key variables is not readily available, and applicability of some relevant biophysical parameters and indicators developed for the terrestrial realm (such as Leaf Area Index, NDVI) remain to be tested for the characterisation of foreshores. The advent of the superspectral Sentinel-2 MSI opens up the potential to detect such characteristics from a spaceborne platform in a consistent way, based on an appropriate spectral, spatial and temporal resolution, with substantial (regional) coverage. However, a thorough assessment is required to optimize and validate retrieval schemes for the spatial characterisation of foreshores. At eight case-study sites across Europe (Spain, Romania, United Kingdom and the Netherlands), ground referencing will be executed to aid the retrieval of information from Sentinel imagery. Validation includes measurements of sediment type and vegetation density/biomass and hyperspectral reflectance of vegetation types. The in situ and remote sensing data will be combined with measurements on wave attenuation and erosion/deposition regimes. The results will provide insight in forshore stability and in the buffering function of foreshores and floodplains. From the collected data general relationships between foreshore and floodplain characteristics and flood risk mitigation properties will be derived. These will be implemented in a GIS based tool for integrating wetlands into cost efficient and safe flood risk management strategies.This project has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration.POSTE

    Sentinel-2 remote sensing of Zostera noltei-dominated intertidal seagrass meadows

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    Accurate habitat mapping methods are urgently required for the monitoring, conservation, and management of blue carbon ecosystems and their associated services. This study focuses on exposed intertidal seagrass meadows, which play a major role in the functioning of nearshore ecosystems. Using Sentinel-2 (S2) data, we demonstrate that satellite remote sensing can be used to map seagrass percent cover (SPC) and leaf biomass (SB), and to characterize its seasonal dynamics. In situ radiometric and biological data were acquired from three intertidal meadows of Zostera noltei along the European Atlantic coast in the summers of 2018 and 2019. This information allowed algorithms to estimate SPC and SB from a vegetation index to be developed and assessed. Importantly, a single SPC algorithm could consistently be used to study Z. noltei-dominated meadows at several sites along the European Atlantic coast. To analyze the seagrass seasonal cycle and to select images corresponding to its maximal development, a two-year S2 dataset was acquired for a French study site in Bourgneuf Bay. The po-tential of S2 to characterize the Z. noltei seasonal cycle was demonstrated for exposed intertidal meadows. The SPC map that best represented seagrass growth annual maximum was validated using in situ measurements, resulting in a root mean square difference of 14%. The SPC and SB maps displayed a patchy distribution, influenced by emersion time, mudflat topology, and seagrass growth pattern. The ability of S2 to measure the surface area of different classes of seagrass cover was investigated, and surface metrics based on seagrass areas with SPC >= 50% and SPC >= 80% were computed to estimate the interannual variation in the areal extent of the meadow. Due to the high spatial resolution (pixel size of 10 m), frequent revisit time (<= 5 days), and long-term objective of the S2 mission, S2-derived seagrass time-series are expected to contribute to current coastal ecosystem management, such as the European Water Framework Directive, but to also guide future adaptation plans to face global change in coastal areas. Finally, recommendations for future intertidal seagrass studies are proposed

    Praderas de fanerógamas marinas en la bahía de Cádiz: conservación y gestión

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    Comunicación técnicaLa bahía de Cádiz es un humedal costero protegido por figuras de protección nacionales (Parque Natural) e internacionales (LIC, Convención Ramsar) dada su importancia ecológica. La biodiversidad biológica incluye numerosas especies de macroalgas, invertebrados, peces y aves. Un hecho de singular importancia, y poco conocido por las administraciones públicas, es que en este humedal conviven 3 de las 4 especies de fanerógamas marinas, o más estrictamente angiospermas marinas, de Europa. Las praderas de Cymodocea nodosa y Zostera noltii junto con escasos rodales de Zostera marina, proporcionan numerosos servicios ecológicos que están siendo estudiados por el grupo de Estructura y Dinámica de Ecosistemas Acuáticos de la Universidad de Cádiz. Desde hace 15 años hemos desarrollado proyectos tanto nacionales como internacionales en la bahía con el fin de poner en práctica bases ecológicas para la gestión de estas praderas como parte integrante del ecosistema. Estas herramientas abarcan desde un nivel ecofisiológico muy reduccionista (tasas fotosintéticas, incorporación de nutrientes), hasta un nivel más holista (mapas de cobertura, efecto a gran escala de variables ambientales, utilización de información para la estimación de la calidad ecológica de la masa de agua). Las actuaciones desarrolladas incluyen la consolidación de una red de voluntariado (FAMAR) para la recogida y análisis de la información. El trabajo que se presenta resume la información disponible, con series de datos recogidos y analizados durante la última década, para la gestión de las praderas y el estado de conservación de las mismas. Se incluyen además algunas perspectivas para la gestión.Proyecto ECOLAGUNES del programa europeo Interreg del espacio SUDOE (SOE1/P2/F153), proyecto IMACHYDRO, del Ministerio de Ciencia e Innovación (CTM2008-00012/MAR), proyectos de excelencia de la Junta de Andalucía FUNDIV (P07-RNM-02516), PAMBIO (P08-RNM-03783) y BAHÍA (P06-RNM0163713 página
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