Luis Ferrero-Vicente

Bioindicators are useful tools for brine discharge assessment.BOPA and echinoderms are strongly affected by salinity variability.BOPA and echinoderms reflected the impact caused by brine discharge.Bioindicators require multiple reference stations due to natural variation.Development of desalination projects requires simple methodologies and tools for cost-effective and environmentally-sensitive management. Sentinel taxa and biotic indices are easily interpreted in the perspective of environment management. Echinoderms are potential sentinel taxon to gauge the impact produced by brine discharge and the BOPA index is considered an effective tool for monitoring different types of impact. Salinity increase due to desalination brine discharge was evaluated in terms of these two indicators. They reflected the environmental impact and recovery after implementation of a mitigation measure. Echinoderms disappeared at the station closest to the discharge during the years with highest salinity and then recovered their abundance after installation of a diffuser reduced the salinity increase. In the same period, BOPA responded due to the decrease in sensitive amphipods and the increase in tolerant polychaete families when salinities rose. Although salinity changes explained most of the observed variability in both indicators, other abiotic parameters were also significant in explaining this variability.

ABSTRACT 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.

ABSTRACT The present study analyses the distribution and diversity of sipunculan species inhabiting soft substrata in the Gulf of Va-lencia and Cape Nao (western Mediterranean) in relation to the characteristics of the sediment. Eighty-seven stations in 14 localities were sampled annually from 2004 to 2008. Nine species were reported, with Aspidosiphon (Aspidosiphon) muelleri being the dominant species in the area and Thysanocardia procera the most widely distributed. Pearson correla-tion coefficient and multivariate analysis showed how sipunculan abundances of certain species were related to the sedi-ment characteristics, especially grain size. The shell-dwelling species A. (A.) muelleri and Phascolion (Phascolion) caupo were dominant in stations with high amount of coarse sand and gravel, while Sipunculus (Sipunculus) nudus appeared in stations dominated by fine sand with low organic content. Pn. (Pn.) caupo and T. procera were reported for the first time in the study area. Moreover, it was the second record of Pn. (Pn.) caupo for the Mediterranean Sea.

We analysed the distribution of soft bottom sipun-culans from San Pedro del Pinatar (Western Mediterranean). This study was carried out from December 2005 to June 2010, sampling with biannual periodicity (June and December). Physical and chemical parameters of the sediment were analysed (granulometry, organic matter content, pH, bottom salinity and shelter availability). Nine different species and subspecies were identified, belonging to five families. Aspidosiphon muelleri muelleri was the dominant species, accumulating 89.06% of the total abundance of sipunculans. Higher sipunculan abundances were correlated with stations of higher percentage of coarse sand, empty mollusc shells and empty tubes of the serpulid polychaete Ditrupa arietina, where some of the recorded species live. Sediment characteristics played the main role controlling the sipunculans distribution. Anthropogenic impacts could be indirectly affecting their distribution, changing the sediment characteristics. Resumen Sipuncúlidos de fondos blandos de San Pedro del Pinatar (Mediterráneo occidental): influencia de los impactos antropogénicos y las características del sedimento sobre su distribución.— Se analizó la distribución de los sipuncúlidos de fondos blandos de San Pedro del Pinatar (Mediterráneo occidental). Este estudio se llevó a cabo entre diciembre de 2005 y junio de 2010, muestreando con periodicidad semestral (junio y diciembre). Se analizaron parámetros físicos y químicos del sedimento (granulometría, contenido de materia orgánica, pH, salinidad de fondo y disponibilidad de refugio). Nueve especies y subespecies diferentes fueron identificadas, pertenecientes a cinco familias. Aspidosiphon muelleri muelleri fue la especie dominante, acumulando el 89,06% de la abundancia total de sipuncúlidos. Las mayores abundancias de sipuncúlidos se correlacionaron con las estaciones con mayores porcentajes de arena gruesa, conchas de moluscos vacías y tubos vacíos del poliqueto serpúlido Ditrupa arietina, donde viven algunas de las especies registradas. Las características del sedimento jugaron el papel principal en el control de la distribución de sipuncúlidos. Los impactos antropogénicos podrían estar afectando indirectamente su distribución, cambiando las características del sedimento.

ABSTRACT Se han analizado los posibles efectos de un vertido hipersalino procedente de la planta desalinizadora de San Pedro del Pinatar (Murcia, SE España) sobre los poblamientos de sipuncúlidos de sustrato blando. El estudio se ha realizado en el periodo comprendido entre diciembre de 2005 y diciembre de 2009, realizándose dos muestreos anuales, en junio y diciembre. Se ha comparado un transecto frente al punto de descarga con dos transectos control situados al norte y al sur. Se tomaron cuatro puntos de muestreo por cada transecto, manteniendo una profundidad constante entre transectos. Los sipuncúlidos fueron identificados a nivel especie y se analizaron los parámetros físico-químicos del sedimento. Se han utilizado técnicas analíticas univariantes y multivariantes. Se han identificado ocho especies, pertenecientes a cinco familias diferentes. Aspidoshipon muelleri es la especie dominante, representando un 89,11% de la abundancia total. Las abundancias más altas de sipuncúlidos se relacionan con las estaciones que presentan un sedimento con mayor fracción de arenas medias y conchas de moluscos vacías, donde habitan frecuentemente las especies Aspidosiphon muelleri, Phascolion caupo y Phascolion strombus. A pesar de que no se ha registrado ningún sipuncúlido en la estación situada en el punto de vertido, es difícil detectar un efecto directo del vertido de salmuera sobre estas comunidades, debido a la heterogeneidad que presentan los fondos de las diferentes estaciones. Las características físicas del sedimento son el factor determinante a la hora de explicar la distribución del poblamiento de sipuncúlidos.

A population of the sipunculan worm Aspidosiphon muelleri Diesing 1851, located in temperate waters of the western Mediterranean Sea, was monitored monthly for a year, and some aspects related to its ecology and reproductive biology are shown in the present work. Sex ratio for this population was close to 1:1 (54% females vs. 46% males), thus indicating a dioecious reproduction, although a lack of sexual dimorphism. Maturation size for the females was 4–5 mm; this size might be reached by A. muelleri in few months. The population density increased notably during the summer (June-August). Spawning event date was indirectly estimated from the data of percentage of mature females and average size of the eggs. Both variables (% mature females and average egg size) were significantly correlated to shallow water temperature (Pearson correlation; P=0.003 & P=0.001 respectively). Egg size was also significantly correlated to average irradiance level (Pearson correlation; P=0.044). Spawning ...