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Accurate data on community structure is a priority issue in studying coastal habitats facing human pressures. The recent development of remote sensing tools has offered a ground-breaking way to collect ecological information at a very fine scale, especially using low-cost aerial photogrammetry. Although coastal mapping is carried out using Unmanned Aerial Vehicles (UAVs or drones), they can provide limited information regarding underwater benthic habitats. To achieve a precise characterisation of underwater habitat types and species assemblages, new imagery acquisition instruments become necessary to support accurate mapping programmes. Therefore, this study aims to evaluate an integrated approach based on Structure from Motion (SfM) photogrammetric acquisition using low-cost Unmanned Aerial (UAV) and Surface (USV) Vehicles to finely map shallow benthic communities, which determine the high complexity of coastal environments. The photogrammetric outputs, including both UAV-based high (sub-meter) and USV-based ultra-high (sub-centimetre) raster products such as orthophoto mosaics and Digital Surface Models (DSMs), were classified using Object-Based Image Analysis (OBIA) approach. The application of a supervised learning method based on Support Vector Machines (SVM) classification resulted in good overall classification accuracies > 70%, proving to be a practical and feasible tool for analysing both aerial and underwater ultra-high spatial resolution imagery. The detected seabed cover classes included above and below-water key coastal features of ecological interest such as seagrass beds, “banquettes” deposits and hard bottoms. Using USV-based imagery can considerably improve the identification of specific organisms with a critical role in benthic communities, such as photophilous macroalgal beds. We conclude that the integrated use of low-cost unmanned aerial and surface vehicles and GIS processing is an effective strategy for allowing fully remote detailed data on shallow water benthic communities.

Seagrass habitats are recognised as providing essential ecosystem services and being indicators of estuarine health, and are under increasing threat globally. This study examined the spatial and temporal variability of four dominant seagrass genera (Posidonia, Zostera, Halophila and Ruppia) among five geomorphic estuary types and four levels of estuarine maturity in New South Wales (NSW), Australia, over a 40-year period. While there was a decline in total seagrass area across NSW over the last 40 years, this was mostly attributed to Ruppia, the genus with the greatest temporal variability. The composition of seagrasses differed among estuary types and with the maturity of Barrier estuaries. Posidonia was found to be the least temporally variable genus over the last 40 years. The greatest overall annual rate of decline was 1.85% year−1 for Ruppia which is considerably less than the global estimated rate of 5% year−1 over the same time period. Average annual rates of decline were greater over the last 18 years than the last 40 years, but only for the most transient genera and only in some estuary types. Recent declines in Posidonia were greater than those over the last 40 years in two of the most heavily urbanised estuaries. The temporal variability of Zostera differed significantly among estuary types and decreased with increasing water depth across all estuaries. No relationships were found between catchment disturbances, measured as land use or population density, and seagrass change or temporal variability at the estuary scale. Our results highlight the importance of distinguishing among seagrass genera when interpreting changes over time and considering factors such as estuary type, which is effectively a surrogate for environmental conditions.

Isoprene is an important biogenic volatile organic compound (BVOC), with a contribution to annual greenhouse gas emissions similar to that of methane in terms of carbon equivalent. Isoprene is mostly produced by terrestrial vegetation, although marine ecosystems also play an important role in isoprene production. Here, we report isoprene fluxes from warm temperate seagrass communities dominated by specific seagrass species (Posidonia australis, Zostera muelleri and Halophila ovalis) in Wallis Lake, NSW, Australia, and from tropical seagrass communities (H. ovalis/Halodule uninervis mixed patches) on Lizard Island, QLD, Australia. P. australis and Z. muelleri were net isoprene sinks (-0.6 ± 0.1 and -3.4 ± 2.0 nmol m-2 h-1, respectively), whereas H. ovalis (2.4 ± 0.2 nmol m-2 h-1) and mixed patches of H. ovalis/H. uninervis (13.2 ± 3.2 nmol m-2 h-1) were a net source of isoprene, indicating that seagrass communities can be both a source of and a sink for isoprene on a local scale depending on species. Overall, isoprene effluxes were more than 5 times higher on Lizard Island than in Wallis Lake, likely due to higher temperatures and prolonged sunlight on Lizard Island during the time of measurement. Wallis Lake and Lizard Island seagrass communities emit isoprene to the water column at an average rate of -0.3 and 8 mg m-2 yr-1, respectively. Seagrass communities are a benthic source of isoprene in coastal waters, but only make a small contribution (2.3 Gg C yr-1) to the global marine isoprene flux (11.6 Tg C yr-1).

Herein, we investigated for the first time the microbiota from the hepatopancreas of the talitrid amphipod Orchestia montagui and the oniscidean isopod Tylos ponticus, two crustacean species associated with beached leaves of the seagrass Posidonia oceanica (Posidonia banquette). We carried out a metabarcoding analysis based on several hypervariable regions of the bacterial 16S rRNA gene. At the same time, three representative habitats of the supralittoral zone, namely leaf surface of Posidonia banquette, sandy shore and surface seawater were examined by means of bacterial metabarcoding analysis. Our data analyses indicated that the bacterial microbiota from the hepatopancreas and that from the marine habitats form distinct groups in terms of the taxonomic composition. Comparative analyses revealed that some bacteria were associated with the hepatopancreas of the syntopic O. montagui and T. ponticus but were not detected in the supralittoral habitats. This suggests that distinct components of the microbial community may be uniquely adapted within the hepatopancreas. The microbiota from the hepatopancreas of O. montagui was more complex than that of T. ponticus. However, the putative presence of polysaccharide-degrading bacteria in both species indicated symbiotic microbiomes that might be involved in the functionality of the hepatopancreas. A deeper understanding of halophilic hepatopancreatic symbionts in the supralittoral zone also has broad relevance to applied research, particularly to the biotechnological sector related to marine biomass conversion.

This work presents the development and field testing of a novel adaptive visual information gathering (AVIG) framework for autonomous exploration of benthic environments using AUVs. The objective is to adapt dynamically the robot exploration using the visual information gathered online. This framework is based on a novel decision-time adaptive replanning (DAR) behavior that works together with a sparse Gaussian process (SGP) for environmental modeling and a Convolutional Neural Network (CNN) for semantic image segmentation. The framework is executed in mission time. The SGP uses semantic data obtained from stereo images to probabilistically model the spatial distribution of certain species of seagrass that colonize the sea bottom forming widespread meadows. The uncertainty of the probabilistic model provides a measure of sampling informativeness to the DAR behavior. The DAR behavior has been designed to execute successive informative paths, without stopping, considering the newest information obtained from the SGP. We solve the information path planning (IPP) problem by means of a novel depth-first (DF) version of the Monte Carlo tree search (MCTS). The DF-MCTS method has been designed to explore the state-space in a depth-first fashion, provide solution paths of a given length in an anytime manner, and reward smooth paths for field realization with non-holonomic robots. The complete framework has been integrated in a ROS environment as a high level layer of the AUV software architecture. A set of simulations and field testing show the effectiveness of the framework to gather data in P. oceanica environments.

Este artículo contiene 15 páginas, 6 figuras, 1 tabla., Seagrass meadows rank among the most significant organic carbon (Corg) sinks on earth. We examined the variability in seagrass soil Corg stocks and composition across Australia and identified the main drivers of variability, applying a spatially hierarchical approach that incorporates bioregions and geomorphic settings. Top 30 cm soil Corg stocks were similar across bioregions and geomorphic settings (min-max: 20–26 Mg Corg ha−1), but meadows formed by large species (i.e., Amphibolis spp. and Posidonia spp.) showed higher stocks (24–29 Mg Corg ha−1) than those formed by smaller species (e.g., Halodule, Halophila, Ruppia, Zostera, Cymodocea, and Syringodium; 12–21 Mg Corg ha−1). In temperate coastal meadows dominated by large species, soil Corg stocks mainly derived from seagrass Corg (72 ± 2%), while allochthonous Corg dominated soil Corg stocks in meadows formed by small species in temperate and tropical estuarine meadows (64 ± 5%). In temperate coastal meadows, soil Corg stocks were enhanced by low hydrodynamic exposure associated with high mud and seagrass Corg contents. In temperate estuarine meadows, soil Corg stocks were enhanced by high contributions of seagrass Corg, low to moderate solar radiation, and low human pressure. In tropical estuarine meadows formed by small species, large soil Corg stocks were mainly associated with low hydrodynamic energy, low rainfall, and high solar radiation. These results showcase that bioregion and geomorphic setting are not necessarily good predictors of soil Corg stocks and that site-specific estimates based on local environmental factors are needed for Blue Carbon projects and greenhouse gases accounting purposes., This study was delivered as part of the Pilot Projects program of the Land Restoration Fund, supported by the Queensland Government, Deakin University, The University of Queensland, James Cook University, CSIRO, HSBC, Qantas, Australian Government Department of Industry, Science, Energy and Resources, NQ Dry Tropics, Great Barrier Reef Foundation and Greencollar. We are thankful for the funding provided by Deakin University (to PIM and MDPC), Qantas (to PIM and MDPC) and HSBC (to PIM and MDPC). MR, PY, PIM were supported through ARC Linkage grant LP160100492, and PIM and CEL were supported through ARC Linkage grant LP160100242. NJW is funded through Australian Government National Environment Science Program (Tropical Water Quality Hub). MFA was funded through an Advance Queensland Industry Research Fellowship, Queensland Government. CS was funded by ECU Higher Degree by Research Scholarship

Marine caves are abundant throughout the Mediterranean Sea, but most studies have focused on those occurring in its western part so far. However, the few studies covering the Eastern Mediterranean showed that its caves are characterized by high diversity. We here describe the molluscan assemblage of the Kakoskali submarine cave in northwestern Cyprus, a shallow water cave characterized by the occurrence of large biostalactites. To avoid any destructive sampling in such a delicate environment, we used death assemblages from cave sediments (that can faithfully represent the composition of nearby living assemblages) sampled across a gradient from the inner chamber to nearby Posidonia patches outside the cave. Inside the cave, we found 217 species, 38% of the molluscan fauna currently known from Cyprus; sampling saturation was 0.99 and the estimated diversity at perfect coverage was 258 (+ 17%) species. One species has never been reported from Cyprus previously (Austronucula perminima) and another one is a first record for the entire Eastern Mediterranean (Hyalogyra zibrowii). We also report an unidentified Pyramidellidae which has eluded all identification efforts. In the cave, we found only five (2%) non-indigenous species represented by 50 individuals (1%). The Posidonia patches outside the cave hosted 143 species with a coverage of 0.98 and an estimated 180 (+ 26%) species at perfect coverage. The high diversity here recorded highlights the important role played by caves as biodiversity reservoirs. Additionally, this diversity is higher than the one described from Western Mediterranean caves inspected with comparable methods, contributing to questioning the magnitude of the west to east decreasing diversity gradient in the Mediterranean Sea.

Este artículo contiene 10 páginas, 4 figuras., The prevalence of local adaptation and phenotypic plasticity among populations is critical to accurately predicting when and where climate change impacts will occur. Currently, comparisons of thermal performance between populations are untested for most marine species or overlooked by models predicting the thermal sensitivity of species to extirpation. Here we compared the ecological response and recovery of seagrass populations (Posidonia oceanica) to thermal stress throughout a year-long translocation experiment across a 2800- km gradient in ocean climate. Transplants in central and warm-edge locations experienced temperatures > 29°C, representing thermal anomalies > 5°C above long-term maxima for cool-edge populations, 1.5°C for central and < 1°C for warm-edge populations. Cool-edge, central and warm-edge populations differed in thermal performance when grown under common conditions, but patterns contrasted with expectations based on thermal geography. Cool-edge populations did not differ from warm-edge populations under common conditions and performed significantly better than central populations in growth and survival. Our findings reveal that thermal performance does not necessarily reflect the thermal geography of a species. We demonstrate that warm-edge populations can be less sensitive to thermal stress than cooler, central populations suggesting that Mediterranean seagrasses have greater resilience to warming than current paradigms suggest., This study was funded by Fundacion BBVA (project Interbioclima). SB received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement no. 659246, Juan de la Cierva Formacion contract from the Spanish Ministry of Economy, Industry and Competitiveness and the Australian Research Council (DE200100900). NM and SB received funding from the Spanish Ministry of Economy, Industry and Competitiveness (MedShift, CGL2015-71809-P). JB received funding from the Spanish Ministry of Science and Innovation, Juan de la Cierva FJC18-035566-I. TA received funding from the Spanish Ministry of Science and Innovation (Project: UMBRAL, CTM2017-86695-C3-1-R).

The aim of this study was to test Posidonia oceanica (L.) Delile seagrass residues (leaves and fibers) as growing media component to improve the nutritional quality of two different brassica microgreens (Mizuna and Rapini). We hypothesized that addition of posidonia residues in the substrate would result in higher concentration of certain mineral nutrients in the edible parts of plants. Substrates were obtained by mixing leaves and fibers, each material at the rate of 25, 50 and 75% (v/v), with a peat based commercial substrate, that was also used at 100% rate as a control treatment. Two experiments were carried out (Experiment 1: Mizuna microgreens production in growth chamber conditions; Experiment 2: Mizuna and Rapini microgreens production in greenhouse conditions). Plant growth measurements and chemical analysis on edible parts (mineral tissue composition and main bioactive compounds - polyphenol, chlorophylls and carotenoids contents) were performed in order to evaluate the effects of the different substrates on growth and nutritional composition of brassica microgreens. In order to evaluate the consumer safety, daily intake, percentage of recommended daily allowance for I (RDA-I) and hazard quotient (HQ) for I intake through consumption of 50 and 100 g portions of Rapini microgreens were calculated. Posidonia in the growing media mixtures increased I and B content in edible parts of microgreens. The calculated HQ underlines the safety of these products. Results confirm the possibility to improve nutritional profile of brassica microgreens by using this natural material as a growing media component, resulting in a sustainable approach.

A significant example of circular economy application concept is the recycling of wastes through co-composting to obtain techno-soils and composts. The objective of this paper was to demonstrate that the co-composting of Posidonia oceanica residues with decontaminated sediments is an effective method to manage two kinds of waste and transform them in a suitable material for the preparation of growth substrates. To demonstrate the effectiveness of the co-composting process, a protocol, involving physical–chemical, biochemical, and toxicological parameters, has been followed. Moreover, to evaluate the quality of the different Posidonia-based composts, the characteristics have been compared with threshold values proposed in the Italian regulation for plant growth substrates and to specific parameters from the scientific literature. All the obtained composts responded to the main characteristics for composting and growing media preparation provided in national and international regulations, in terms of pH (6.7–7.6), electrical conductivity (0.13–0.30 dS/m), and total organic carbon content (6.62–27.9 C%). Moreover, results about humic carbon (16.6–21.9 C%), germination index (139–158%), enzymatic activities (B-glucosidase: 3538–5367 mmol MUB/kg ds H), bulk density (0.30–0.83 g/cm3), and cation exchange capacity (43.3–126 meq/100 g ds) proved the quality of the P. oceanica and sediment based composts. These results are an endorsement of Posidonia with sediment-based composts use as a constituent of techno-soils and, as a component for the preparation of nursery growth substrate. It is possible to claim that the co-composting process is an alternative management strategy for decontaminated sediments and P. oceanica residues to be recommended. Adequate policies are needed in order to recycle Posidonia oceanica residues and decontaminated sediments, namely two kinds of waste, into a secondary raw material, namely techno-soil, thus implementing the concept of the circular economy.

Mediterranean brachiopods are elusive organisms to find alive even if the bathymetric range of some species extends to very shallow waters. We here record an abundant population of Joania cordata (Risso, 1826) and Argyrotheca cuneata (Risso, 1826) in the rhizome layer of a Posidonia oceanica (Linne) Delile, 1813 meadow in Plakias, southwestern Crete from 5 to 20 m depth. Altogether, we collected 963 living individuals and 4309 shells by suction sampling; it is the largest collection of living brachiopods in Posidonia meadows ever reported. Although literature records on the occurrence of shallow-water brachiopods in this habitat are few, we claim that Posidonia rhizomes are a particularly suitable infralittoral habitat for these organisms due to their sciaphilous conditions. Suction sampling is an effective technique to collect them and can enable the discovery of many more populations in the Mediterranean Sea.

Hybridization is common among plants and has been crucial in the evolution of many aquatic plant groups. However, hybrid individuals are often difficult to identify, particularly in the marine environment. We aim to confirm a hybrid origin between two seagrass species for a morphologically-intermediate plant observed in shallow subtidal environments near Perth, Western Australia. Both morphological measures and DNA markers demonstrated a clear case for hybridization among two sympatric Posidonia species from different species complexes: Posidonia australis and P. coriacea. All five samples with the intermediate morphology had the same multilocus genotype (MLG), providing evidence that it resulted from a single hybridization event, followed by local clonal (rhizome) expansion. This result highlights weak reproductive barriers within the genus Posidonia, a trait common among other seagrass genera with sympatric ranges, apparently overlapping morphologies and low phylogenetic divergence.

Aegagropiles are round-shaped conglomerations of Posidonia oceanica debris commonly found along the coasts of the Mediterranean Sea. This study presents a detailed description of the composition of aegagropiles in terms of their internal organisation in different layers (and the orientation of the fibres in these layers), the proportion of constituent elements (fibres and minerals) and the histological (by way of microscopic observations) nature of all of these aegagropiles elements. The aim of this work is to take a detailed interest in the structure of the aegagropiles of Posidonia oceanica and to determine the process that forms them. Aegagropiles are an assemblage of two types of debris from the P. oceanica meadow: (1) plant-based: fibres more or less degraded from P. oceanica shoots (leaves and rhizomes) and (2) mineral particles such as silicates and biotic Ca-carbonate debris. On the basis of structural and compositional observations, we proposed an elucidation of the cycle in several phases: initiation of a “roll” by aggregation of litter fibres and sand in the ripple marks, growth, breakdown of the roll into small balls (microbial and mechanical degradation) and export of aegagropiles down (into the abyss) or on to the beaches. Calculations estimate that considering its density of 0.2 g/cm3, an aegagropile represents the accumulation of fibres from approximately 25 shoots of P. oceanica.

Las fanerógamas marinas constituyen un grupo de angiospermas que colonizaron de forma secundaria el medio marino. En la actualidad se conocen unas 60 especies de este grupo de plantas de las que 4 de ellas se desarrollan en el mar de Alborán, presentando con una distribución diferenciada. Sus adaptciones fisiológicas y morfológicas has permitido un exitoso desarrollo en estos ambientes constituyendo en muchos casos las comunidasdes climax sobre los sustratos blandos infralitorales. Las biocenosis que desarrollan son de gran importancia desde varios puntos de vista si bien en la actualidad sufren una serie de amenazas e impactos que empobrecen en gran medida los servicos ecosistémcios que nos aportan. Departamento de Botánica y Fisiología Vegetal, Universidad de Málaga

Trabajo de fin de doble grado en Ciencias Ambientales y Ciencias del Mar, realizado en la modalidad de prácticas de empresa., Durante la realización de estas prácticas de empresa, se trabajó en el ámbito del desarrollo rural y pesquero. Para el ámbito del desarrollo rural se creó una base de datos del banco de semillas de variedades locales cultivadas tradicionalmente en el territorio, facilitando la gestión de solicitudes y cesiones de semillas entre el banco y los agricultores. También se realizó la extracción y conservación de material vegetal, generando nuevas entradas al banco de semillas. Se realizaron inspecciones de los cultivos de trigo, cebada y avena de variedad local. Además, se continuó el ensayo agronómico de lechugas y se analizaron los resultados obtenidos. En el ámbito del desarrollo pesquero se realizaron campañas de buceo científico, participé en un total de 32 inmersiones de buceo científico en siete puntos distintos de las islas, donde se caracterizaron las praderas de posidonia (Posidonia oceánica) y el sedimento de estas localizaciones. Se trabajó con el sector pesquero para comprobar si las artes de pesca menores utilizadas en la pesca del gerret (Spicara smaris) son perjudiciales para este ecosistema. Además, se realizaron visitas a las cofradías de pescadores de Ibiza y San Antonio de Portmany, donde se estudió el proceso que se lleva a cabo desde el desembarco de las capturas hasta su venta. También se estudiaron las diferentes artes de pesca utilizadas en la Isla de Ibiza, para entender la evolución de este sector a lo largo del tiempo. Se realizaron muestreos biológicos de las capturas realizadas por los arrastreros en las Islas, donde aprendí a utilizar todas las herramientas necesarias para hacer un correcto muestreo biológico de las capturas de un arrastrero y a identificar diferentes especies de peces, moluscos y bivalvos entre otras.

Summary An extensive potential source rock sampling survey was conducted in Ionian Zone, Epirus region, western Greece. Several samples were collected from the known potential source rock intervals (Triassic formations, ‘Lower Posidonia Shales’, ‘Upper Posidonia Shales’, ‘Vigla Shales’) as well as from new intervals showing promisin g source rock characteristics (dark color, clay content etc.). The samples were examined by organic geochemical means using the Rock-Eval 6 instrument by Vinci Technologies, France. Concerning the known potential source rock intervals, the ‘Lower Posidonia Shales’ show generally good petroleum potential, ‘Upper Posidonia Shales’ show no hydrocarbon potential, ‘Vigla Shales’ show fair to good petroleum potential but only in one locality. Several Triassic black carbonate samples are considered as ‘spent’ source rocks except from one sample showing fair petroleum potential and immature organic matter. A new potential source rock was discovered at the base of the Jurassic sequence showing very high amounts of TOC wt.% Type I/II immature organic matter with a ver y high remaining hydrocarbon potential. Oligocene-Miocene clastics show generally low TOC values with low gas potential, whereas contain very sparce, cm-thick organic-rich and oil-prone seams.

Mediterranean seagrass Posidonia oceanica is used as a common biological indicator in the monitoring programmes of the Water Framework Directive (WFD) due to its structural and functional features providing information about the status of coastal ecosystems. In this respect synthetic seascape ecological indices using P. oceanica: the Conservation Index (CI), the Substitution Index (SI), the Phase Shift Index (PSI) and the Patchiness Index (PI) provide supplementary data on the meadow status and on the pressures affecting the meadows besides evaluating the water quality. However, these indices have not been adopted by the European Union Water Framework Directive (WFD). This survey is, therefore focused on the qualification of the status of coastal ecosystems in the North Aegean Sea with an integrated approach based on the synthetic (the CI, the SI, the PSI and the PI) and biotic indices (Biotic Index of Posidonia and Ecosystem Based Quality Index) of P. oceanica. Measurements of several parameters are conducted in four sites (2 natural, 2 anthropized) in Gokceada (North Aegean). The preliminary results confirm the efficiency of synthetic and biotic indices to evaluate the ecosystem status in relation with anthropogenic pressures at a local extent. The mean value of the CI corresponds to a "good" status, while the value of the BiPo Index corresponds to a "moderate" and the value of the EBQI corresponds to a "poor" status for Gokceada. Maximum values of the synthetic and biotic indices are recorded in natural sites. On the contrary, minimum values are recorded in anthropized sites close to marine-based activities. In addition, an early stage of a phase shift (PSI < 0.25) is recorded due to a low substitution with Caulerpa cylindracea spread around fragmented meadows and dead matte areas. Also, relations (p < 0.05) between the scores of the Land Uses Simplified Index (LUSI) and combined synthetic and biotic indices of P. oceanica, verified the negative impacts of anthropogenic pressures on the benthic ecosystems of the North Aegean Sea where the data is deficient.

Lightweight, hydrophobic, adsorbent pads based on aerogels from different cellulosic and nanocellulosic fractions extracted from Posidonia oceanica waste biomass were developed by a simple freeze-drying and PLA dipping method. The pure (nano)cellulosic aerogels presented highly porous structures, capable of adsorbing large amounts of oil (up to ∼34 g oil/g aerogel); however, they lost their integrity when soaked in water. The incorporation of PLA hydrophobized the aerogels and improved significantly their mechanical performance (up to 10-fold increase in the compression stress). The most porous aerogel structures, obtained with the lowest (nano)cellulosic concentrations and with the less purified fractions, incorporated greater amounts of PLA upon dipping, which was mostly distributed filling in the pores. All the PLA-coated (nano)cellulosic aerogels presented a hydrophobic behavior, with contact angles of 95-130° and selectively adsorbing greater amounts of oil (5.9-9.2 g oil/g aerogel) than water (2.8-6.7 g H2O/g aerogel). These materials present a great potential as adsorbent pads for oil spill cleaning and food packaging applications., This work was financially supported by the project RTI2018-094408-J-I00 from the Spanish Ministry of Science, Innovation and Universities, the “Agencia Estatal de Investigación” and co-funded by the European Union’s Horizon 2020 research and innovation programme (ERA-Net SUSFOOD2). Isaac Benito-Gonzalez was recipient of an Erasmus Plus grant (European programme) from the Polytechnic University of Valencia (UPV) in order to carry out part of the experimental work at Teagasc (Fermoy, Ireland).

La adición de 100 μM NO3- incrementa en 0.4 ± 0.2 mM la concentración citosólica de Na+ (17 ± 2 mM Na+). En oscuridad, el transporte de NO3- es menor y aumenta la concentración citosólica de NO3- (5.7 ± 0.2 mM). El aumento del HCO3- en el medio provoca la disminución del NO3- citosólico, y el aumento del transporte de NO3-, lo que sugiere un flujo de salida de NO3- inducido por alto HCO3-. Las tasas netas de incorporación de NO3- o Pi disminuyen más del 70% en ausencia de Na+. Esta dependencia de Na+ también se observa en el transporte de alta afinidad de los aminoácidos L-Ala y L-Cys (KM = 37 ± 11 μM y KM = 10 ± 1 μM, respectivamente). Así, P. oceanica usa los H+ para impulsar la incorporación directa de HCO3-, cuya deshidratación interna provocaría la disminución de NO3- en el citosol, mientras que la incorporación de NO3-, Pi y aminoácidos está mediada por transportadores de alta afinidad dependientes de Na+, mecanismo que parece ser clave en el proceso de adaptación de las fanerógamas marinas al medio ambiente marino. Fecha de lectura de Tesis Doctoral: 30 septiembre 2019 s fanerógamas marinas constituyen el único grupo de angiospermas que ha colonizado el medio marino, desarrollando mecanismos de adaptación a un ambiente caracterizado por una elevada salinidad, un pH alcalino y una baja disponibilidad de nutrientes. En este trabajo se ha determinado el sistema que energiza la membrana plasmática y su permeabilidad relativa a Na+/K+, los mecanismos de transporte de HCO3-, NO3-, Pi y aminoácidos, y la homeostasis citosólica de NO3- en células del mesófilo foliar de la fanerógama marina Posidonia oceanica L. (Delile). La principal metodología empleada ha sido la electrofisiología, usando microelectrodos ión-selectivo de aplicación interna (citosol) y externa. Además, se ha analizado la respuesta fotosintética al incremento de Ci disuelto (CO2 o HCO3-) mediante la medida polarográfica de oxígeno. Los resultados indican que la bomba primaria de la membrana plasmática es una H+‐ATPasa de tipo P, sensible a fusicocina y que la permeabilidad al Na+ es muy baja (PNa+/PK+ = 0.0046 ± 0.0012). La adición de HCO3- despolariza la membrana y provoca la acidificación transitoria del citosol, indicando que el HCO3- es incorporado en simporte con H+. A dicha acidificación le sigue una alcalinización que se inhibe por EZ, lo que sugiere la deshidratación interna del HCO3-. La constante de semisaturación (S0.5 = 0.35 ± 0.07 mM HCO3-) similar a la afinidad del transporte (KM = 0.36 ± 0.04 mM HCO3-) sugiere un mecanismo eficiente de incorporación este ión. Por otra parte, la adición de concentraciones micromolares de NO3- o Pi provoca despolarizaciones de la membrana plasmática, que se saturan respecto a la concentración añadida (KM = 8.7 ± 1 μM NO3- y KM = 5.8 ± 0.8 μM Pi) y son dependientes de la presencia de Na+ en el medio, mostrando también una cinética de saturación para este ión (KM = 7.2 ± 2 mM Na+ para el NO3- y KM = 4.3 ± 0.5 mM Na+ para el Pi).

Posidonia oceanica is a marine phanerogam that buries a significant part of its belowground production forming an organic bioconstruction known as mat. Despite Posidonia seagrass mats have proven to be reliable archives of long-term environmental change, palaeoecological studies using seagrass archives are still scarce. Here we reconstruct four millennia of environmental dynamics in the NE coast of Spain by analysing the carbon and nitrogen stable isotopic composition of P. oceanica sheaths, the proportion of different seagrass organs throughout the seagrass mat and other sedimentological proxies. The palaeoenvironmental reconstruction informs on long-term ecosystem productivity and nutrient loading, which have been linked to global (e.g., solar radiation) and local (e.g., land-use changes) factors. The long-term environmental records obtained are compared with previous palaeoecological records obtained for the area, showing a common environmental history. First, a relative seagrass ecosystem stability at ~4000 and 2000 cal. yr BP. Then, after a productivity peak at ~1400-800 cal. yr BP, productivity shows an abrupt decline to unprecedented low values. The fluctuations in ecosystem productivity are likely explained by increases in nutrient inputs related to human activities – mostly in the bay watershed – concomitantly with changes in total solar radiation. Cumulative anthropogenic stressors after Roman times may have started to affect ecosystem resilience, dynamics and productivity, with more abrupt regime shifts during the last millennium. These results add into recent research showing the potential of seagrass archives in reconstructing environmental change and seagrass post-disturbance dynamics, hence providing unvaluable information for improving the efficiency in managing these key coastal ecosystems.

Seeds of Australian species of the seagrass genus Posidonia are covered by a membranous wing that we hypothesize plays a fundamental role in seed establishment in sandy, wave swept marine environments. Dimensions of the seed and membrane were quantified under electron microscopy and micro-CT scans, and used to model rotational, drag and lift forces. Seeds maintain contact with the seabed in the presence of strong turbulence: the larger the wing, the more stable the seed. Wing surface area increases from P. sinuosa P. australis P.coriacea correlating with their ability to establish in increasingly energetic environments. This unique seed trait in a marine angiosperm corresponds to adaptive pressures imposed on seagrass species along 7,500 km of Australia’s coastline, from open, high energy coasts to calmer environments in bays and estuaries.

Seagrass meadows are one of the most important coastal habitats across the globe. These are mainly constituted by the marine plants of the genus Posidonia and Thalassia. In the Mediterranean Sea, P...

The use of seaweed biomass for energy production is under consideration in several countries of the world. This paper, after a review of other scientific papers on the subject, aims at evaluating the pros and cons of the use of Posidonia oceanica as biomass source for anaerobic digestion (AD) in territorial contexts where the presence of large quantities of beached seagrass is also a problem for the tourism economy. The case chosen is the Sardinian town of Alghero. The presence of large Posidonia leaves deposits on the beaches is responsible for some inconveniences, such as the foul odour derived from the natural decomposition process. Other problems are the reduced usability and the untidy appearance of the beach, which lays within the town’s urban context. This condition reduces the competitiveness of the hotels, bars and restaurants that are located on the seaside promenade and the quality of life of nearby residents and tourists. The methodology used to define and analyse the problem is based on the following steps: territorial analysis, evaluation of the available quantities, regulatory issues, economic and social impacts evaluation. Although the overall quantity of fresh Posidonia evaluated by the municipal authorities is of approximately 200 tonnes per year, other calculation methods show that the potential quantity of raw biomass is far superior (up to 3.500 tons). It is possible then to determine the potential CH 4 yield and the consequent thermal/electric output after an AD process. Based on the quantitative data of our analysis we are able to determine a cost structure and to evaluate, from the economic point of view, the adequacy of the choice of installing an AD plant fuelled with Posidonia oceanica in the town’s industrial area. The study has a preliminary approach, as the data used for the biogas production estimation are derived from laboratory tests. Furthermore, the effects of the removal of the seagrass from the beaches, provided that the operations are carried out in a sustainable and non-destructive way, could improve the quality of life of residents and tourists in the nearby areas. Based on our findings we can suggest that the usage of Posidonia oceanica in the studied case is potentially interesting as a resource for biogas production although further research is needed to validate this solution. The future research efforts will have to concentrate on several issues: definition of the available biomass quantities, evaluation of the biogas yield of Posidonia on an industrial scale, available co-digestion solutions, treatment and possible use of the digestate sludge.

Seagrasses are marine angiosperms that have evolved from terrestrial ancestors. Photosynthetic activity on seed has been studied before in Posidonia genus. T. testudinum and P. oceanica share some evolutionary aspects as they live in more stable environments. As in P. oceanica , T. testudinim seed is also green-coloured suggesting the presence of photosynthetic pigments. Here, the photosynthetic activity in the T. testudinum seed was examined. Measurements of photosynthetic production, pigment content and maximum PSII photochemical efficiency (Fv: Fm) were determined. Epifluorescence microscopy analysis was used to obtain evidence of photosynthetic structures within the seed. This study revealed photosynthetic activity in seed epidermis which increased linearly with increasing irradiance. T. testudinum seed displayed a higher Photosynthetic efficiency (α), and lower light saturated photosynthesis (P. max), saturation irradiance (Ek), and compensation irradiance (Ec) compared to adult leaves. Epifluorescence microscopy images of the seeds showed an epidermis composed of relatively small, regular cells, tending towards a rectangular shape, containing abundant chloroplasts. The photobiological behaviour results in the T. testudinum seed being strongly adapted to colonize environments with reduced light availability. Photosynthetic activity in T. testudinum seed shed some light on seagrass dispersal and expansion mechanisms.

Talitrid amphipods (sandhoppers and beach fleas) are typical of the supralittoral zone. They are known to thrive on stranded materials, including detrital marine angiosperms and macroalgae, as well as occasional dead animals. In this work, the gut microbiota of five species of talitrid amphipods (Talitrus saltator, Talorchestia ugolinii, Sardorchestia pelecaniformis, Orchestia montagui and Orchestia stephenseni) collected in Sardinia (Italy) has been investigated through: i) metabarcoding analysis of the amplified 16S rRNA V4 region; and ii) quantification of family 48 glycosyl hydrolase genes (GHF48), involved in cellulose degradation. Results indicate that, though talitrid gut biodiversity is not directly related to taxon or sampling locality, the animals' digestive tracts may host species-specific bacterial communities. In particular, gut microbiota of O. montagui, an inhabitant of Posidonia banquettes and macro-algae mat, showed the greatest differences in taxonomic composition and the highest proportion of GHF48 genes with respect to 16S rRNA genes. These results suggest that the different talitrid species may host species-specific bacterial communities whose function could partially reflect the different microhabitats and food preferences of their host.

Posidonia oceanica (Linnaeus) Delile 1813 is an endemic and the most widespread seagrass species of the Mediterranean Sea. Seagrass meadows are one of the most productive ecosystems on Earth, providing habitat to numerous organisms. Therefore, mapping of seagrass meadows is of crucial importance for conservation and coastal management purposes. Here we present an integrated geographic information system approach with SCUBA diving, providing a cost effective method to monitor seagrass beds at shallow coastal habitats. In this case study P. oceanica meadows were mapped in Ufakdere region of Kaş (Antalya) coastal area between April – September 2015. A total of 25000 m2 are were screened to create seagrass coverage maps. Results indicate that P. oceanica meadows cover 21200 m2 and we estimated that 520 m2 of this area is highly damaged. This integrated approach provided one of the most detailed small-scale Posidonia mapping in Turkey and this time and cost effective methodology can be applied to any seagrass meadow with great ease to increase our knowledge on this important habitat.

The continental shelf of Spain is the underwater surface beyond the coast to a depth of 200 m. It is an area of great fishing and ecological importance. In the peninsula, it is relatively narrow and is minimal in the Canary Islands. Its narrowness has led to the search for distant fishing grounds, such as those of Newfoundland, exploited by Basque fishermen since centuries ago. The European interest in exploiting the Saharan bank and in reaching fishing agreements with Morocco and Mauritania is due to the need to provide an outlet for a large fishing fleet that is increasingly efficient in its catches.

Among the fauna inhabiting the Posidonia oceanica seagrass meadow, holothurians are particularly abundant and provide essential ecological roles, including organic matter recycling within seagrass sediments. This study aimed to investigate the trophic niche of four holothurians of the order Holothuriida [ Holothuria poli (Delle Chiaje, 1824), Holothuria tubulosa (Gmelin, 1791), Holothuria sanctori (Delle Chiaje, 1823) and Holothuria forskali (Delle Chiaje, 1823)] inhabiting P. oceanica meadows, through the measurement of nitrogen and carbon stable isotope ratios. Two shallow and contrasting sites of the littoral region of Mostaganem (North West Algeria) were chosen. The first site, located in Stidia, is weakly impacted by human activities. The second site, located in Salamandre, is highly impacted by human activities (industries, harbor facilities). High values of δ15N in holothurians and their food sources were observed at both sites. The δ13C values showed a lower contribution from detritic Posidonia than in other areas. This could be a consequence of P. oceanica bed degradation in the studied area. The stable isotope approach did not reveal dietary differences between species, and the four holothurians species exhibited significant isotopic niche overlap. However, niche sizes differed between species showing more variable individual trophic diversity in some species ( H. tubulosa and H. sanctori in Salamandre; H. forskali in Stidia). If niche segregation does occur, it is not in terms of general resource use. More likely, it would be the abundance of food sources, the different life habits and their micro-habitats that may explain their co-existence in the P. oceanica seagrass meadow.

Global changes affect the entire planet at all scales, terrestrial and marine. The impact of anthropogenic pressures on marine ecosystems has been relatively little studied because of the lack of data and the difficulty to acquire it. Fine resolution cartographic data (1:10 000) of marine habitats on French Mediterranean coasts have recently become available (Andromede Oceanologie, 2014). This allows using landscape ecology approaches to study the spatial configurations of these habitats, their evolution through time and confront that to anthropogenic and environmental pressures. Here we take advantage of this new data to study Posidonia oceania meadows, a marine habitat of great ecological and economic importance. Posidonia oceanica is an endemic species to the Mediterranean Sea. Posidonia oceanica is also an indicator of the ecological quality of coastal waters since changes in its spatial distribution reflect changes in environmental conditions. The spatial cover of Posidonia oceanica meadows has declined sharply in the last 50 years, in particular because of increased human activities along the coast. In this study, we tested the relative influence (and possible interactions) of anthropogenic coastal pressures and environmental variables (Previmer data) on the decline of Posidonia oceanica meadows in the French Mediterranean sea. Different composition and configuration landscape descriptors were calculated for different grid cells (400m x 400m; 200m x 200m, 100m x 100m), between 0 and 40 m depth over 1800 km of French Mediterranean coastline (Mainland + Corsica). An approach using Random Forest was applied to explain these indices with the anthropogenic and environmental factors and to identify the factors that contribute the most to the decline of Posidonia oceanica meadows. With a model that explains 87% of overall variance, our results show a very important effect of environmental factors on the decline and the patchs cohesion of Posidonia oceanica meadows. Anthropogenic pressures also have a destructive effect on the posidonia, because if the intensity of the pressures is high, the decline is strong and the cohesion between the patches is weak.The identification of tipping points for all environmental variables shows that some seagrasses are in areas of good environmental conditions and others in weak environmental conditions. The human impact on the seagrass surface regression and their spatial organization is clearly shown and it is important to define priority areas for conservation actions.

Biotic and abiotic factors influence the accumulation of organic carbon (Corg) in seagrass ecosystems. We surveyed Posidonia sinuosa meadows growing in different water depths to assess the variability in the sources, stocks and accumulation rates of Corg. We show that over the last 500 years, P. sinuosa meadows closer to the upper limit of distribution (at 2–4 m depth) accumulated 3- to 4-fold higher Corg stocks (averaging 6.3 kg Corg m−2) at 3- to 4-fold higher rates (12.8 g Corg m−2 yr−1) compared to meadows closer to the deep limits of distribution (at 6–8 m depth; 1.8 kg Corg m−2 and 3.6 g Corg m−2 yr−1). In shallower meadows, Corg stocks were mostly derived from seagrass detritus (88 % in average) compared to meadows closer to the deep limit of distribution (45 % on average). In addition, soil accumulation rates and fine-grained sediment content (

12 páginas, 5 figuras, 4 tablas, 4 apéndices., The study of a Posidonia australis sedimentary archive has provided a record of changes in element concentrations (Al, Fe, Mn, Pb, Zn, Cr, Cd, Co, As, Cu, Ni and S) over the last 3000 years in the Australian marine environment. Human-derived contamination in Oyster Harbor (SWAustralia) started ~100 years ago (AD ~1900) and exponentially increased until present. This appears to be related to European colonization of Australia and the subsequent impact of human activities, namely mining, coal and metal production, and extensive agriculture. Two contamination periods of different magnitude have been identified: Expansion period (EXP, AD ~1900–1970) and Establishment period (EST, AD ~1970 to present). Enrichments of chemical elementswith respect to baseline concentrations (in samples older than ~115 cal years BP) were found for all elements studied in both periods, except for Ni, As and S. The highest enrichment factors were obtained for the EST period (ranging from 1.3-fold increase in Cu to 7.2-fold in Zn concentrations) compared to the EXP period (1.1-fold increase for Cu and Cr to 2.4-fold increase for Pb). Zinc, Pb, Mn and Co concentrations during both periods were 2- to 7-fold higher than baseline levels. This study demonstrates the value of Posidonia mats as long-termarchives of element concentrations and trends in coastal ecosystems. We also provide preliminary evidence on the potential for Posidonia meadows to act as significant long-term biogeochemical sinks of chemical elements., Thisworkwas supported by the ECU Faculty Research Grant Scheme, the ECU Early Career Research Grant Scheme, and the CSIRO Flagship Marine & Coastal Carbon Biogeochemical Cluster with funding from the CSIRO Flagship Collaboration Fund. PMwas supported by a Gledden Visiting Fellowship and AAO by Obra Social “la Caixa”.

The aim of this study is to investigate the effect of chemical treatment method on the properties of Posidonia fibers. The chemical treatment which is carried out is a combined hydrogen peroxide and sodium hydroxide treatment. First, an investigation of the treatment processes was undertaken. Secondly, the physical properties (linear density, diameter and ratio length per diameter), the mechanical properties (tenacity, elongation) and chemical properties (FT-IR spectra and X ray diffraction) of posidonia fibers were investigated. The optimum operating conditions were identified using a factorial design.

The main objective of this research is to study the effect of fiber weight ratio and chemical fiber modification on flexural properties of composites reinforced with Posidonia fiber. An unsaturated polyester matrix reinforced with untreated and treated Posidonia fibers was fabricated under various fiber weight ratios. Results showed that the combined chemical treatment provided better mechanical properties of composites in comparison with untreated fiber. The fiber weight ratio influenced the flexural properties of composites. Indeed, a maximum value of flexural modulus was observed for 10% fiber weight ratio for composites reinforced with treated fibers. SEM photographs revealed a different fracture surface between Posidonia fibers reinforced polyester composites.

The accumulation of Posidonia oceanica dead leaves on the beaches of the Mediterranean shores is a natural phenomenon. They are either temporary or permanent structures (banquettes) and represent a valuable resource, with important ecosystem functions including coastal protection against erosion. Nevertheless, the perception of these plant accumulations by the different stakeholders (beach managers, local administrations and tourists) is often negative, they consider these deposits a malevolent waste to be removed, rather than a natural and valuable component of the coastline. We propose an integrated/beneficial management model for posidonia deposits, called ECOLOGICAL BEACH, firstly proposed in France, and recently implemented and applied in Italy. The model promotes the preservation of posidonia beach casts on site, with a balanced coexistence of natural and anthropic elements. The model fosters the several important ecosystem services of the beach casts and contributes to coastal preservation. To successfully spread the model, several activities must be implemented: a regulatory framework, the collection of data about the occurrence of beach casts, management protocols and educational programs. The most important activity is the educational one, based on the dissemination of the ecological and economic value of the beach casts, aimed at switching the perception of this phenomenon towards positive appraisal.

Este artículo contiene 8 páginas, 1 tabla, 3 figuras., Seagrass restoration has been suggested as a Blue Carbon (BC) strategy for climate change mitigation. For Nationally Determined Contributions (NDC) and carbon crediting schemes, BC projects need to demonstrate ‘additionality’, that is enhanced CO2 sequestration and/or avoided greenhouse gas emissions following management actions. This typically requires determining soil carbon accumulation rates (CAR), which is often done using radionuclides or surface elevation tables to estimate sedimentation rates. Here we undertook a case study, using 210Pb and 14C dating, to detect possible changes in Corg stocks and CAR following the loss and partial recovery of Posidonia seagrass meadows in South Australia since 1980–90s. The 210Pb data revealed a lack of accumulation of excess 210Pb in most sites, suggesting negligible accumulation of sediments, intense mixing of the upper layers, or accumulation of reworked sediments, precluding the estimation of reliable CAR at decadal time scales. This limitation was also encountered with 14C. The inability to compare sites over analogous periods of time prevented quantifying differences in soil Corg sequestration, thereby to demonstrate additionality. The lack of significant differences in soil Corg stocks among sites which never suffered seagrass loss, those showing recovery and those with no recovery (5.7 ± 1.2, 4.5 ± 0.7 and 3.3 ± 0.3 kg Corg m-2 within the top meter, respectively) also precluded estimates of soil Corg gains or losses. Our findings demonstrate that, while 210Pb and 14C provide important information on sediment deposition dynamics, it is not straightforward to demonstrate additionality using radionuclides in low depositional seagrass habitats exposed to hydrodynamic energy, features which may be encountered in seagrass sites. We provide insights for the selection of suitable habitats for seagrass BC projects, suggest possible alternative methods for estimating additionality, and discuss the implications of the findings for the implementation of seagrass BC strategies to mitigate greenhouse gas emissions., This research was funded by Edith Cowan University, the Environmental Protection Authority of South Australia and SA Water, through ECU-Industry grant (G1001729). OS, PM and PL were supported by ARC (DE170101524, LE170100219). Funding was provided to PM through an Australian Research Council LIEF Project (LE170100219) and by the Generalitat de Catalunya (Grant 2017 SGR-1588). This work is contributing to the ICTA ‘‘Unit of Excellence’’ (MinECo, MDM2015- 0552).

The Trealla Limestone, which forms a veneer of foraminiferal-rich limestone and covers over 4000 km2 of the tectonically stable Southern Carnarvon Platform, contains the oldest evidence for seagrass meadows known in Western Australia. It belongs to Lower Tf1 Letter Stage (based on larger benthic foraminifers) of the Burdigalian, within interval 19–16 Ma, and is the only Miocene unit on the platform. The Trealla Limestone here is coeval to the deeper water lower part of the much thicker Trealla Limestone in the Exmouth Sub-basin to the northwest. A seagrass-meadow depositional environment is indicated by most of the studied microfacies based on comparisons with modern sediment composition and foraminiferal assemblages found in innermost shelf seagrass banks between 23°S and 32°S on the present Western Australian coast. Some levels in the Trealla Limestone on the platform (e.g. with abundant miliolid foraminifers, and absence of coral debris) probably were deposited in and around dense seagrass meadows similar to those present today in the metahaline (40–55 ppt salinity) reaches of Shark Bay; whereas other levels (e.g. coral floatstone) were deposited under normal-marine conditions. Based on comparisons with modern carbonate sediment and biota in the region, the biogenic composition of the Trealla Limestone on the platform suggests winter minimum sea-surface temperatures within the range of 17–22 °C. The Nullabor Limestone in the Eucla Basin, at 10° further south on the southern Australian margin, is similar, at least in part, in composition and age to the Trealla Limestone on the Southern Carnarvon Platform. Both may have been deposited during a Burdigalian sea-level rise, and during part of the Miocene climate optimum recognized elsewhere. Sediment composition and foraminiferal assemblages (including epiphytic types) found in the Trealla and Nullabor limestones are similar to those in the modern seagrass banks of the region. This suggests that seagrasses similar to the extensive Posidonia and Amphibolus stands, which are dominant today between 25°S and 35°S along the Western Australian coast, were widespread during the Burdigalian.

The study of a Posidonia sinuosa sedimentary archive has delivered a millenary record of environmental change in Cockburn Sound (Western Australia). Ecosystem change is a major environmental problem challenging sustainable coastal development worldwide, and this study shows baseline trends and shifts in ecological processes in coastal ecosystems under environmental stress. The concentrations and fluxes of biogeochemical elements over the last 3,500 years indicate that important changes in ecosystem dynamics occurred over the last 1,000 years, in particular after ~1900's, probably related to establishment of seagrass meadows in the area and to local and regional human activities (industry and coastal development), respectively. The establishment of seagrasses ~1,000 years ago in the area of study is supported by the appearance of Posidonia fibres from ~40 cm soil depth until the core top, higher δ13C values indicating a larger contribution of seagrass-matter to the soil organic carbon pool, and increased concentration of fine sediments driven by the effect of seagrass canopy in enhancing sedimentation. The comparison of organic carbon, nutrients and metal concentrations and fluxes between pre- and post-establishment of seagrasses shows that seagrass establishment resulted in up to 9-fold increase in the soil biogeochemical sink. In ~1900's, shifts in the concentrations of metals, carbonates, organic carbon, sediment grain size, and δ13C and δ15N values of the organic matter were detected, demonstrating an alteration in seagrass ecosystem functioning following the onset of European settlement. Anthropogenic activities, and in particular the construction of a causeway in 1970's, enhanced seagrass soil organic carbon and metal accumulation rates by 36- and 39-fold, respectively, showing that human-made structures can enhance the biogeochemical sink capacity of seagrasses. Here we reconstruct the impact of human activities on seagrass ecosystem dynamics and blue carbon, which can inform local management of Cockburn Sound and seagrass conservation for climate change mitigation and adaptation.

The high organic carbon (OC) stores in seagrass meadows have led to their recognition as significant Blue Carbon sinks, though the diagenetic conditions that enable OC retention in seagrass soils remain poorly understood. In this study, seagrass soils were sampled from a Posidonia australis meadow in Oyster Harbour (Albany; south-western Australia) to investigate the preservation of sedimentary OC. We analysed soil characteristics (colour, grain size and redox potential), radiocarbon age, and characterised the soil organic matter (OM) using solid state CP/MAS 13C NMR spectroscopy to examine the preservation of OM down the soil profile. There was minimal change in organic composition over 1,700 years of accumulation, indicating long-term OM preservation. Primarily, this preservation appears to be driven by the recalcitrance of seagrass detritus buried in anoxic soils. The majority (70–83%) of total sedimentary OM comprised components directly attributable to seagrass origins (lignin, carbohydrate and black carbon-like matter), while the remainder consisted mostly of protein, some of which may have been present in seagrass biomass, along with likely contributions from algae and microbes. Although black carbon originates from organic matter combustion, here we provide evidence that the 13C NMR signal identified as black carbon-like matter in our soils is possibly associated with seagrass-derived organic matter consisting of degraded lignin products or other non-pyrogenic aromatics. The increase in the relative abundance of this black carbon-like matter with aging suggests its selective preservation. The relative abundances of carbohydrates significantly decreased with age down core (i.e. they appeared to be selectively decomposed), while lignin and protein did not show any quantitative changes in relative abundance (non-selective preservation). These findings demonstrate the exceptional preservation of P. australis derived OC, which contributes to our understanding of the higher OC storage capacity of Posidonia compared to other seagrass species.

The Great Australian Bight is a large carbonate cold water environment located on the central and western portions of the southern Australia. Seagrasses (Posidonia sp.) and macroalgae benthic habitats are widely distributed in the shallow water environment of southern Australia, contributing to the carbonate factory. This study investigated the distribution of modern benthic foraminiferal assemblages in the microtidal wave-dominated inner-shelf of Esperance Bay (southwestern Australia), that lies on the western margin of the Great Australian Bight. Benthic foraminifera were taxonomically identified and biotic parameters (species richness, density, Fisher-α index, Shannon–Weaver index, dominance) were calculated. Multivariate analyses (Hierarchical Cluster Analysis, Principal Component Analysis) were performed to understand foraminiferal distribution in the context of environmental conditions. Four main Foraminiferal assemblages have been recognized: (I) a nearshore assemblage of dense seagrass meadow, dominated by Lamellodiscorbis dimidiatus, Elphidium craticulatum, Elphidium crispum, Cibicidoides lobatulus, II) a second assemblage associated with unvegetated seabed (approximately 30 m depth) with Lamellodiscorbis dimidiatus, Elphidium crispum, Quinqueloculina disparilis, III) a third assemblage in the central sector of the bay, characterized by a discontinuous and mixed seagrass-algae coverage with Lamellodiscorbis dimidiatus, Elphidium crispum, Elphidium macellum, Cibicides refulgens, and Quinqueloculina poeyana, and IV) an epiphytic assemblage of transitional zone from the coastline to the upper limit of a mixed seagrass-algae meadow, dominated by Elphidium crispum, Chrysalidinella dimorpha, Planulinoides biconcava, Planoglabratella opercularis, Rugobolivinella elegans. The spatial distribution of the four assemblages appears closely related to sediment texture, seagrass cover and depth, but it is also influenced by the shoreface morphology and the hydrodynamic energy. The understanding of the ecological parameters that influence benthic foraminiferal distribution, composition and assemblage structure within seagrass meadows is useful for paleoecological and paleoenvironmental interpretations.

This paper focuses on the detection of Posidonia oceanica in underwater images. The input image is split into a set of patches that are classified as depicting Posidonia or not. Two different Neural Networks are proposed to perform the classification. A region growing algorithm able to accurately detect the contours of the Posidonia oceanica from the output of the classifier is also described. The experimental results, performed using images gathered in coastal areas of Mallorca (Spain), show that our proposal reaches the 95.5% of accuracy, the 95.8% of precision and the 95.4% of recall with only a 4.6% of fallout. When compared to previous studies, these results surpass those of methods based on Machine Learning and are comparable, even superior in some cases, to recent Deep Learning approaches. The advantages in terms of computational requirements, which are crucial in underwater robotics, are also highlighted. In particular, our proposal works up to 8.6 times faster than other Deep Learning methods.

Mediterranean seagrass Posidonia oceanica is used as a 'biological quality element' in the long-term monitoring programmes of the Water Framework Directive (WFD 2000/60/EC) for the evaluation of ecological status of coastal waters. Due to its low resilience to anthropogenic pressures, P. oceanica meadows have disappeared irreversibly along some of the Mediterranean coasts. The main objective of this survey, is therefore to compare the ecological status of coastal waters and P. oceanica meadows in two islands from Eastern (Gokceada, Turkey) and Western (Corsica, France) Mediterranean Sea based on the Posidonia Biotic Index (BiPo) and the Vitality Index besides concentrating on: (i) their consistency in different environmental conditions present in the Mediterranean Sea, (ii) their effectiveness to discriminate the ecological status of coastal waters in relation to different anthropogenic pressures and (iii) their application capacity to initiate long-term data series for monitoring the evolution of the meadows in less evaluated regions (i.e. from the Eastern Mediterranean). The measurements of several descriptors of P. oceanica are interpreted based on the BiPo and the Vitality indices for 2 regions; 9 sites from Gokceada and 15 sites from Corsica exposed to different human pressures. The mean BiPo and Vitality indices are higher in Corsica than in Gokceada, where the values correspond to a "good" status for Corsica and a "moderate" status in Gokceada. The application of these biotic indices showed their feasibility and comparability to assess the ecological status in different environmental conditions. Significant relationships between the scores of Anthropization index and the EQR values of the BiPo index (r = - 0.745, p < 0.01) and the Vitality index (r = - 0.702, p < 0.01) highlighted their efficiency to determine the seagrass degradation in the sites subjected to higher pressure levels. It can be assumed that this study initiates the development of long-term data series and also meets the essential data deficiency in less evaluated regions.

The suitability of Posidonia oceanica as feedstock for anaerobic digestion process was evaluated carrying out several biochemical methane potential tests. No clear evidence of process inhibition were observed during tests. Nevertheless, the very high lignin content of Posidonia did not allow the organic matter solubilization by microbial lithic enzymes, thus limiting the effectiveness of the anaerobic digestion process. Therefore, Posidonia was subjected to thermal (132 °C) and thermo-chemical pre-treatment in order to increase its anaerobic digestibility. The opportunity of reducing biomass stress due to the high salinity of Posidonia suspension (performing a washing operation before anaerobic digestion) was also evaluated. Thermal treatment and salt removal allowed only a limited increase in anaerobic digestion process efficiency. Whilst thermo-chemical pre-treatment at 132 °C in presence of HCl 0.40% resulted in a relevant increase of Posidonia biodegradability leading to a specific methane production higher than 90 mL/gVS and a VS removal efficiency of about 50%.

Posidonia oceanica (L.) Delile is a seagrass, the only group of vascular plants to colonize the marine environment. Seawater is an extreme yet stable environment characterized by high salinity, alkaline pH and low availability of essential nutrients, such as nitrate and phosphate. Classical depletion experiments, membrane potential and cytosolic sodium measurements were used to characterize the high-affinity NO3−, Pi and amino acids uptake mechanisms in this species. Net uptake rates of both NO3− and Pi were reduced by more than 70% in the absence of Na+. Micromolar concentrations of NO3− depolarized mesophyll leaf cells plasma membrane. Depolarizations showed saturation kinetics (Km = 8.7 ± 1 μM NO3−), which were not observed in the absence of Na+. NO3− induced depolarizations at increasing Na+ also showed saturation kinetics (Km = 7.2 ± 2 mM Na+). Cytosolic Na+ measured in P. oceanica leaf cells (17 ± 2 mM Na+) increased by 0.4 ± 0.2 mM Na+ upon the addition of 100 μM NO3−. Na+-dependence was also observed for high-affinity l-ala and l-cys uptake and high-affinity Pi transport. All together, these results strongly suggest that NO3−, amino acids and Pi uptake in P. oceanica leaf cells are mediated by high-affinity Na+-dependent transport systems. This mechanism seems to be a key step in the process of adaptation of seagrasses to the marine environment.

The coastal waters of southern and south-western Australia are home to almost 30,000 km2 of seagrass, dominated by temperate endemic species of the genera Posidonia and Amphibolis. In this region, seagrasses are common in estuaries and sheltered coastal areas including bays, lees of islands, headlands, and fringing coastal reefs. Additionally, extensive meadows exist in the inverse estuaries of the Gulfs in South Australia, and in Shark Bay in Western Australia. This chapter explores (i) how geological time has shaped the coastline and influenced seagrasses, (ii) present day habitats and drivers, (iii) how biogeography patterns previously reported have been altered due to anthropogenic and climate impacts, and (iv) emerging threats and management issues for this region. Species diversity in this region rivals those of tropical environments, and many species have been found more than 30 km offshore and at depths greater than 40 m. Seagrasses in this region face a future of risk from multiple stressors at the ecosystem scale with coastal development, eutrophication, extreme climate events and global warming. However, our recent improved understanding of seagrass recruitment, restoration and resilience provides hope for the future management of these extraordinary underwater habitats.

© Springer International Publishing AG, part of Springer Nature 2018. Seagrasses are an organismal biological group united by their ability to grow in marine environments. As marine flowering plants they have evolved a combined suite of adaptations multiple times enabling the four known lineages containing species of seagrass to survive, and thrive, in the sea. Unlike many other biological groups of plants however, seagrasses are all derived from a single order of flowering plants, the Alismatales. This order, being derived early in the evolution of the monocotyledons, is comprised predominantly of aquatic plants, of all forms- emergent, submerged, freshwater, estuarine and marine. A review of seagrass fossils suggests that new discoveries of seagrass fossils along with confirmation of some earlier finds lead to a clear signal that some seagrass species had a wider distribution in the past compared with today. The discovery of new fossil sites should be encouraged as this will likely produce important valuable information on the evolution of this group. In general the biogeography of seagrasses suggests that these organisms evolved successfully in the Tethys Sea of the Late Cretaceous. However, the modern division into two groups, temperate and tropical tends to suggest that at some point an ecological separation occurred in both the Northern and Southern Hemispheres. There are a disproportionately large number of temperate seagrass species in southern Australia and there is significant endemism shown in Posidonia, Amphibolis and a unique species of Halophila (H. australis). The use of genetic and genomic techniques has begun to explain these distributions but we can expect a much bigger picture to emerge in the near future.

The flammability behavior of an epoxy resin, modified by the addition of Posidonia Oceanica at three concentration levels (8%, 10%,12%), has been investigated by performing cone calorimeter tests. The plant has been preliminary dried and milled to obtain a powder with average size of 0.08 micron, then has been dispersed within the resin prior the cure. Scanning electron microscopy both on the Posidonia and the hybrid composites has been carried out to verify the dispersion and the action mechanism of plant within the resin. Results from cone calorimeter tests showed that the incorporation of Posidonia Oceanica significantly affect the flammability of the epoxy resin by a strong reduction of PHHR up to 52%.The flammability behavior of an epoxy resin, modified by the addition of Posidonia Oceanica at three concentration levels (8%, 10%,12%), has been investigated by performing cone calorimeter tests. The plant has been preliminary dried and milled to obtain a powder with average size of 0.08 micron, then has been dispersed within the resin prior the cure. Scanning electron microscopy both on the Posidonia and the hybrid composites has been carried out to verify the dispersion and the action mechanism of plant within the resin. Results from cone calorimeter tests showed that the incorporation of Posidonia Oceanica significantly affect the flammability of the epoxy resin by a strong reduction of PHHR up to 52%.

Collections of Middle Jurassic ammonites made at the Mwachi River locality, near Mombasa in the late 1980′s and early 1990′s are described. They support previous research concluding a Late Bajocian age for the major or the upper part of the ‘Posidonia shales’, immediately below and above the dividing Massive (Coral) Limestone. The ammonite species are figured and briefly described. Two Upper Bajocian ammonite zones are evidenced: a lower assemblage indicates the Strenoceras niortense Zone and a higher one belonging to the Garantiana garantiana Zone. Most of the ammonites are Tethyan forms with abundant phylloceratids and lytoceratids, some indicating connections with coeval Arabian and Sinai faunas. Palaeobiogeographically the assemblages suggest a deep-water position on the East-African Gondwana margin, with strong faunistic influence from the open Tethys and very restricted connections with the Arabian shallow water regions.