Observations on the ecology and reproductive biology of the sipunculan worm Aspidosiphon muelleri in temperate waters

A population of the sipunculan worm Aspidosiphon muelleri, located in temperate waters of the western Mediterranean Sea, was monitored monthly for a year. Some aspects related to its ecology and reproductive biology are shown in the present work. The sex-ratio for this population was close to 1:1 (54% females vs 46% males), thus indicating a dioecious reproduction, although showing a lack of sexual dimorphism. Oocytes were detected in females from 4–5 mm; this size might be reached by A. muelleri in a few months. The population density increased notably during the summer (June–August). The spawning event date was indirectly estimated from the average size of the oocytes and the percentage of females with free oocytes in the coelom. Both variables were significantly correlated to shallow water temperature (Pearson correlation; P = 0.003 and P = 0.001, respectively). Oocyte size was also significantly correlated to average irradiance level (Pearson correlation; P = 0.044). Spawning took place between August and September (when the water temperature is getting close to its annual maximum) and may last only a few weeks in these temperate waters. The abundance of A. muelleri decreased drastically in September, likely as a consequence of the spawning event effort. Bivalves of the species Epilepton clarkiae were collected together with specimens of A. muelleri living inside the polychaete tubes used as shelters by the sipunculans, with a prevalence of 11.64%. To a lesser extent some Foraminifera were also reported attached to the body of the sipunculans.This research was funded by ‘Mancomunidad Canales del Taibilla’

Seasonal effects of waterfowl grazing on submerged macrophytes: The role of flowers

Seasonal effects of waterfowl (Fulica atra and Anas platyrhynchos) grazing on submerged macrophytes (Ruppia cirrhosa and Potamogeton pectinatus) and the mediating role of flowers on plant consumption were evaluated by exclusion cages and tethering experiments deployed in a Mediterranean lagoon throughout the annual cycle. Despite the low waterfowl abundance recorded in summer, exclusion-cage experiments evidenced intense herbivory on the biomass, canopy height and flowers of R. cirrhosa (flowers abundance was ∼8 times higher inside exclusion cages; 1015.7 ± 269.8 flw m−2). For P. pectinatus, exclusion cage experiments did not evidence waterfowl consumption, in spite of the presence of flowers, which suggest preference for reproductive tissues of R. cirrhosa. In addition, the higher abundance of R. cirrhosa flowers compared to P. pectinatus (∼10 times higher inside the exclusion cages) was likely influenced by more intense herbivory on the former species. Although waterfowl abundance increased in autumn and winter, experiments did not evidence herbivory effects during that period, possibly because of enhanced availability of alternative resources and decreased plant biomass and canopy height reducing encounter rates. Hence, our results suggest that waterfowl effects on submerged macrophytes in Mediterranean aquatic ecosystems are strongly influenced by seasonal changes in the availability of food resources and its flowering events. The higher herbivory on R. cirrhosa and its flowers in summer suggest that waterfowl grazing may be driven by food preference for reproductive tissues, and could have a strong effect on the community structure and abundance of submerged macrophytes

Epiphytes and nutrient contents influence Sarpa salpa herbivory on Caulerpa spp vs. seagrass species in Mediterranean meadows

Mediterranean seagrass ecosystems are endangered by increased colonization of Caulerpa species, which may replace them, affecting key ecosystem processes. The fish Sarpa salpa (L.) is one of the main macroherbivores in the western Mediterranean seagrass meadows which is known to feed on a wide range of macroalgae such as Caulerpa species. In order to elucidate if this consumption could minimize the spread of invasive species, during summer-autumn 2012, we investigate the importance of S. salpa herbivory pressure on C. prolifera and C. cylindracea compared to Posidonia oceanica and Cymodocea nodosa in a mixed meadow. A combination of field experiments and dietary analyses were used to investigate consumption rates, dietary contributions, and feeding preferences for the different macrophytes, including the role of epiphytes and nutrient contents in mediating fish herbivory. In summer, C. nodosa was the most consumed macrophyte (12.75 ± 3.43 mg WW·d−1), probably influenced by higher fish densities, higher nutritional quality of leaves and epiphytes, and by differences in epiphyte composition. Feeding observations suggest that fish may have a variable diet, although with a consistent selection of mixed patches with C. nodosa and C. prolifera. Indeed, food choice experiments suggest that when seagrass leaves are not epiphytized, fish prefer feeding on C. prolifera. Gut content and stable isotopic analyses supported the dietary importance of epiphytes and C. prolifera but also suggested that C. cylindracea could occasionally be an important food item for S. salpa. Our results highlight the role of epiphytes in S. salpa feeding decisions but also suggest that C. nodosa and C. prolifera may have an important contribution to fish diet. The variability in S. salpa diet confirm the need to carry out multiple approach studies for a better understanding of its potential influence over different macrophytes species.This research was funded by the Department of Marine Science and Applied Biology (University of Alicante)

Red de evaluación del potencial en innovación docente del Personal Investigador (PI) en Ciencias Experimentales

El personal investigador (PI) universitario, cuyas tareas son fundamentalmente investigadoras, es un colectivo relativamente pequeño. Se compone del personal investigador en formación (contratados predoctorales), personal contratado con cargo a proyectos (pre o postdoctoral) y los contratados de acceso al sistema español de ciencia y tecnología. Aunque son figuras investigadoras, también se contempla la posibilidad de colaborar en tareas docentes. Nuestra red de innovación docente pretende, mediante la realización de encuestas, valorar el papel del PI en la docencia delas ciencias experimentales y determinar su capacidad para la innovación docente. El PI tiene una alta predisposición a realizar tareas docentes y realizar cursos de formación. Sin embargo su participación en la docencia se suele limitar a la colaboración en clases prácticas cuyo contenido está ya desarrollado, lo cual puede disminuir las posibilidades de que el PI realice innovación docente. En cualquier caso existe una clara predisposición tanto a la mejora mediante la realización de cursos de formación docente, así como a la preparación de material docente innovador. El PI apuesta por un fomento de su participación en tareas docentes, siempre y cuando no influya negativamente en sus tareas de investigación

Evidencia de la respuesta a un enterramiento a corto plazo de la fauna macrobentónica asociada a la fanerógama marina del Mediterráneo Cymodocea nodosa

Sedimentation and burial affect a variety of habitats worldwide, especially within coastal marine systems. In the Mediterranean, seagrasses like Cymodocea nodosa are commonly subjected to sedimentation and, although the response of C. nodosa has been documented, few studies have included macrofaunal responses. We used a manipulative field experiment to examine the effects of a single small-scale, pulse burial event on benthic invertebrate macrofauna. Burial did not affect the total abundance, richness, or diversity of higher taxa nor the live abundance or diversity after 5 days. However, live higher taxa richness decreased by day 3. After 5 days, such decrease reversed and partial recovery seemed to occur. Almost 2 months later, three of the buried plots remained with some additional sedimentation, but the other three had lost their sediment. We compared faunal metrics of buried plots between days 5 and 54 and found greater diversity on day 54, providing evidence that macrofaunal recovery apparent 5 days after burial seemed to persist. Although we likely underestimated the effects and can only be conservative with our conclusions, taken together our results suggest small-scale, pulse burial events can have some negative effects on the C. nodosa-associated benthic macrofaunal community, but the community can recover within a few weeks.La sedimentación y el enterramiento afectan a una gran variedad de hábitats en todo el mundo, especialmente en los sistemas costeros marinos. En el Mediterráneo, las fanerógamas marinas como Cymodocea nodosa suelen estar expuestas a la sedimentación y, a pesar de que la respuesta de C. nodosa ha sido documentada previamente, muy pocos estudios hacen referencia a cómo responde la macrofauna. Se ha usado un experimento manipulativo en el campo para examinar los efectos de un enterramiento súbito y puntual a pequeña escala sobre la fauna de invertebrados macrobentónicos. El enterramiento no afectó a la abundancia total, riqueza o diversidad de especies, ni tampoco a la abundancia o diversidad de individuos vivos 5 días después del enterramiento. Sin embargo, la riqueza de taxones vivos disminuyó a partir del día 3. Pasados 5 días, esa disminución revirtió y parece tener lugar una recuperación parcial. Casi 2 meses después, tres de las parcelas enterradas todavía presentaron algún tipo de sedimentación adicional, pero las otras tres habían perdido el sedimento. Se compararon las métricas de la fauna encontrada en los días 5 y 54 en las parcelas enterradas, y se encontró una alta diversidad para el día 54, evidenciando que la aparente recuperación que tuvo lugar 5 días después del enterramiento parece persistir. A pesar de que probablemente hemos subestimado los efectos y debemos ser conservadores con nuestras conclusiones, al examinar los resultados conjuntamente, sugieren que estos eventos repentinos y puntuales de enterramiento a pequeña escala pueden tener efectos negativos sobre la comunidad de fauna macrobentónica asociada a C. nodosa, la cual se recuperaría en unas pocas semanas

Metabarcoding the eukaryotic community of a threatened, iconic Mediterranean habitat: Posidonia oceanica seagrass meadows

Against the accelerating pace of worldwide species extinction, reliable biodiversity assessments are critical, both as baselines and to track potential declines. DNA metabarcoding techniques allow for fast and comprehensive assessment of biodiversity in both terrestrial and marine habitats. However, these methods need to be adapted and standardised for each ecosystem in order to be effective. Seagrass meadows are among the most diverse marine habitats and are irreplaceable in terms of the ecosystem services they provide, yet metabarcoding has never been implemented for these systems. In this study, we developed and tested a protocol for metabarcoding the eukaryotic community of meadows of the iconic species, Posidonia oceanica L. (Delile). This seagrass is the main habitat-forming species in Mediterranean coastal waters and is known for its high diversity due to the structural complexity of its canopy and rhizome structures. This habitat is experiencing a range-wide retreat, and there is an urgent need for fast and efficient methods for its biomonitoring and detection of early changes. Our proposed method involves direct sampling of the community, collecting and processing the leaves and rhizome strata separately. To test the utility of the method in distinguishing between different meadow conditions, we sampled two distinct meadows that differ in their prevailing wind and surge conditions, and a nearby rocky reef for comparison. We then adapted a method and pipeline for COI metabarcoding using generalist primers that target the eukaryote diversity present. We detected a high diversity in the two meadows analysed (3,350 molecular operational taxonomic units, dominated by Metazoa and Archaeplastida) and a clear differentiation of the seagrass samples from those of the nearby rocky reefs. The leaves and rhizomes harboured clearly distinct assemblages, and differences were also detected between the two meadows sampled. This new tool has the potential to deliver big biodiversity data for seagrass habitats in a fast and efficient way, which is crucial for the implementation of protection and management measures for this key coastal habitat

A temporal record of microplastic pollution in Mediterranean seagrass soils

© 2021 Elsevier Ltd Plastic pollution is emerging as a potential threat to the marine environment. In the current study, we selected seagrass meadows, known to efficiently trap organic and inorganic particles, to investigate the concentrations and dynamics of microplastics in their soil. We assessed microplastic contamination and accumulation in 210Pb dated soil cores collected in Posidonia oceanica meadows at three locations along the Spanish Mediterranean coast, with two sites located in the Almería region (Agua Amarga and Roquetas) and one at Cabrera Island (Santa Maria). Almería is known for its intense agricultural industry with 30 000 ha of plastic-covered greenhouses, while the Cabrera Island is situated far from urban areas. Microplastics were extracted using enzymatic digestion and density separation. The particles were characterized by visual identification and with Fourier-transformed infrared (FTIR) spectroscopy, and related to soil age-depth chronologies. Our findings showed that the microplastic contamination and accumulation was negligible until the mid-1970s, after which plastic particles increased dramatically, with the highest concentrations of microplastic particles (MPP) found in the recent (since 2012) surface soil of Agua Amarga (3819 MPP kg−1), followed by the top-most layers of the soil of the meadows in Roquetas (2173 kg−1) and Santa Maria (68–362 kg−1). The highest accumulation rate was seen in the Roquetas site (8832 MPP m−2 yr−1). The increase in microplastics in the seagrass soil was associated to land-use change following the intensification of the agricultural industry in the area, with a clear relationship between the development of the greenhouse industry in Almería and the concentration of microplastics in the historical soil record. This study shows a direct linkage between intense anthropogenic activity, an extensive use of plastics and high plastic contamination in coastal marine ecosystems such as seagrass meadows. We highlight the need of proper waste management to protect the coastal environment from continuous pollution

Benthic community recovery from brine impact after the implementation of mitigation measures

In many regions, seawater desalination is a growing industry that has its impact on benthic communities. This study analyses the effect on benthic communities of a mitigation measure applied to a brine discharge, using polychaete assemblages as indicator. An eight-year study was conducted at San Pedro del Pinatar (SE Spain) establishing a grid of 12 sites at a depth range of 29–38 m during autumn. Brine discharge started in 2006 and produced a significant decrease in abundance, richness and diversity of polychaete families at the location closest to the discharge, where salinity reached 49. In 2010, a diffuser was deployed at the end of the pipeline in order to increase the mixing, to reduce the impact on benthic communities. After implementation of this mitigation measure, the salinity measured close to discharge was less than 38.5 and a significant recovery in polychaete richness and diversity was detected, to levels similar to those before the discharge. A less evident recovery in abundance was also observed, probably due to different recovery rates of polychaete families. Some families like Paraonidae and Magelonidae were more tolerant to this impact. Others like Syllidae and Capitellidae recovered quickly, although still affected by the discharge, while some families such as Sabellidae and Cirratulidae appeared to recover more slowly.These surveys were funded by the Mancomunidad de Canales del Taibilla

Desarrollo de prácticas de Ciencias del Mar con alumnos de secundaria

La docencia en ciencias en la enseñanza secundaria requiere de experiencias prácticas en el laboratorio o en el campo que permitan desarrollar los contenidos de las materias. El fomento de la vocación científica es el objetivo del programa “Ven a hacer prácticas a la universidad” promovido por la Facultad de Ciencias de la Universidad de Alicante. Esta actividad está dirigida a alumnado de niveles comprendidos entre 4º de ESO y 2º de Bachiller y consiste en la realización de prácticas de laboratorio en los Departamentos de la Facultad de Ciencias. En este trabajo se analiza la participación del Departamento de Ciencias del Mar y Biología Aplicada en dicho programa durante el desarrollo de dos prácticas de laboratorio. El análisis de las encuestas realizadas tanto para el alumnado como para el profesorado participante, permite evaluar las prácticas en los contenidos, el nivel docente, y el grado de satisfacción de ambos colectivos. El desarrollo de este tipo de experiencias permite completar la formación científica en la enseñanza secundaria, y servir de vínculo con la universidad, promoviendo la vocación de futuros científicos y facilitando una posible futura incorporación de los estudiantes a los estudios superiores

Drivers of variation in seagrass-associated amphipods across biogeographical areas

Amphipods are one of the dominant epifaunal groups in seagrass meadows. However, our understanding of the biogeographical patterns in the distribution of these small crustaceans is limited. In this study, we investigated such patterns and the potential drivers in twelve Cymodocea nodosa meadows within four distinctive biogeographical areas across 2000 Km and 13° of latitude in two ocean basins (Mediterranean Sea and Atlantic Ocean). We found that species abundances in the assemblage of seagrass-associated amphipods differed among areas following a pattern largely explained by seagrass leaf area and epiphyte biomass, while the variation pattern in species presence/absence was determined by seagrass density and epiphyte biomass. Seagrass leaf area was also the most important determinant of greater amphipod total density and species richness, while amphipod density also increased with algal cover. Overall, our results evidenced that biogeographical patterns of variation in amphipod assemblages are mainly influenced by components of the habitat structure, which covary with environmental conditions, finding that structurally more complex meadows harboring higher abundance and richness of amphipods associated.info:eu-repo/semantics/publishedVersio