The first two authors listed are primarily responsible for the conceptual and statistical framework for the paper. The contributing authors are listed in alphabetical order. The last two, also in alphabetical order, are the senior authors responsible for the ecological survey and physical modeling component of the effort, respectively. AbstractGlobal climate change has profound implications on species distributions and ecosystem functioning. In the coastal zone, ecological responses may be driven by various biogeochemical and physical environmental factors. Synergistic interactions can occur when the combined effects of stressors exceed their individual effects. The Red Sea, characterized by strong gradients in temperature, salinity, and nutrients along the latitudinal axis provides a unique opportunity to study ecological responses over a range of these environmental variables. Using multiple linear regression models integrating in situ, satellite and oceanographic data, we investigated the response of coral reef taxa to local stressors and recent climate variability. Taxa and functional groups responded to a combination of climate (temperature, salinity, air-sea heat fluxes, irradiance, wind speed), fishing pressure and biogeochemical (chlorophyll a and nutrients -phosphate, nitrate, nitrite) factors. The regression model for each species showed interactive effects of climate, fishing pressure and nutrient variables. The nature of the effects (antagonistic or synergistic) was dependent on the species and stressor pair. Variables consistently associated with the highest number of synergistic interactions included heat flux terms, temperature, and wind speed followed by fishing pressure. Hard corals and coralline algae abundance were sensitive to changing environmental conditions where synergistic interactions decreased their percentage cover. These synergistic interactions suggest that the negative effects of fishing pressure and eutrophication may exacerbate the impact of climate change on corals. A high number of interactions were also recorded for algae, however for this group, synergistic interactions increased algal abundance. This study is unique in applying regression analysis to multiple environmental variables simultaneously to understand stressor interactions in the field. The observed responses have important implications for understanding climate change impacts on marine ecosystems and whether managing local stressors, such as nutrient enrichment and fishing activities, may help mitigate global drivers of change. K E Y W O R D S coral reefs, fishing pressure, macroalgae, nutrients, synergistic interactions, temperature stress

An important aspect of population dynamics for coral reef fishes is the input of new individuals from the pelagic larval pool. However, the high biodiversity and the difficulty of identifying larvae of closely related species represent obstacles to more fully understanding these populations. In this study, we combined morphology and genetic barcoding (Cytochrome Oxidase I gene) to characterize the seasonal patterns of the larval fish community at two sites in close proximity to coral reefs in the central-north Red Sea: one shallower inshore location (50 m depth) and a nearby site located in deeper and more offshore waters (~ 500 m depth). Fish larvae were collected using oblique tows of a 60 cm-bongo net (500 μm mesh size) every month for one year (2013). During the warmer period of the year (June-November), the larval fish stock was comparable between sampling sites. However, during the colder months, abundances were higher in the inshore than in the offshore waters. Taxonomic composition and temporal variation of community structure differed notably between sites, potentially reflecting habitat differences, reproductive patterns of adults, and/or advective processes in the area. Eleven out of a total of 62 recorded families comprised 69–94% of the fish larval community, depending on sampling site and month. Richness of taxa was notably higher in the inshore station compared to the offshore, particularly during the colder period of the year and especially for the gobiids and apogonids. Two mesopelagic taxa (Vinciguerria sp. and Benthosema spp.) comprised an important component of the larval community at the deeper site with only a small and sporadic occurrence in the shallower inshore waters. Our data provide an important baseline reference for the larval fish communities of the central Red Sea, representing the first such study from Saudi Arabian waters.

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Macrofauna community structure within Nazaré Submarine Canyon is analysed and used to assess the potential effects of natural enrichment in this area subjected to accumulation of coastal sediments. A transect including three stations (2894, 3514 and 4141 m) was carried out in the Nazaré Submarine Canyon (NW Portugal) during a cruise of OMEX II programme (Ocean Margin Exchange), in the winter season of 1999. Although data was not collected in order to calculate sedimentation rates, sampling station at 2894 m is located in an area characterised by high levels of sedimentation, thus a high amount of organic matter is expected to be available for the local communities. Faunistic data are discussed in the context of the different features of the stations sampled. Multivariate analysis clearly separates the shallowest station from the other ones, which otherwise appear to be very similar. It also revealed a perceptible gradient along sediment depth at all stations, from shallow to deeper layers. Exceptionally depressed species richness and low evenness values were observed at the 2894 m station. The high number of individuals of a single species, Cossura sp. A, and the atypical diversity, dominance and evenness values obtained for this station support the hypothesis of community disturbance due to organic enrichment.Key words: Deep sea; submarine canyons; NE Atlantic; macrobenthos; community structure; natural organic enrichment RESUMEN: COMUNIDADES MACROBENTÓNICAS PROFUNDAS DEL CAÑÓN SUBMARINO DE NAZARÉ (NW PORTUGAL). -Se analiza la estructura de la comunidad de la macrofauna del cañón submarino de Nazaré y se utiliza para evaluar los efectos potenciales del enriquecimiento natural de esta área sometida a la acumulación de sedimentos costeros. Se realizó un transecto que incluía tres estaciones (2894, 3514 y 4141 m) en el cañón submarino de Nazaré (NW de Portugal), durante una campaña del programa OMEX II (Ocean Margin Exchange), en el invierno de 1999. Aunque no se han obtenido datos para calcular tasas de sedimentación, la estación de muestreo a 2894 m está situada en un área caracterizada por niveles elevados de sedimentación, de modo que es esperable que haya una gran cantidad de materia orgánica disponible para las comunidades locales. Los datos faunísticos se comentan en el contexto de las distintas características de las estaciones muestreadas. El análisis multivariante separa claramente la estación más somera de las otras, que parecen ser muy parecidas entre sí. También revela un gradiente perceptible a lo largo del grosor del sedimento en todas las estaciones, desde las capas someras a las más profundas. En la estación de 2894 m se observaron valores excepcionalmente bajos de riqueza específica y bajos de equitatividad. El elevado número de individuos obtenidos en esta estación refuerza la hipótesis de perturbación de la comunidad debido a enriquecimiento orgánico.Palabras clave: océano profundo, cañones submarinos, Atlántico NE, macrobentos, estructura de la comunidad, enriquecimiento orgánico nat...