Epifaunal Assemblages on Deep-water Corals in Roatan, Honduras

Deep-water corals provide complex habitat structure for diverse assemblages of invertebrates and fishes. Similar to shallow coral reefs, oyster reefs, and seagrass beds, these complex biogenic structures serve many ecosystem functions: (a) as prey items; (b) sites for reproduction; (c) feeding stations, elevating suspension feeders above the benthos; and (d) refuges from predation. Because deep-sea corals provide some of the only three-dimensional habitats in the deep-sea, they may host distinct assemblages of epifauna. Non-destructive video surveys of deep-water coral assemblages were made to depths of 700 m at eight sites off Roatan, Honduras in May and December, 2011. Abundance, species richness, and distribution of epifauna were measured for 305 corals. We observed sixteen morphospecies of coral and twenty-six morphospecies of epifauna. Coral and epifaunal abundances were highest in the 335-449 m depth zone. Some epifauna had high fidelity for a single coral species or for a few species of similar morphological complexity. Other coral species had overlapping assemblages of habitat generalists. This is the first research on the biodiversity of deep-sea coral communities in Roatan, Honduras, and provides information on the assemblages, their depth distributions and ecological interactions

Global Diversity and Phylogeny of the Asteroidea (Echinodermata)

Members of the Asteroidea (phylum Echinodermata), popularly known as starfish or sea stars, are ecologically important and diverse members of marine ecosystems in all of the world's oceans. We present a comprehensive overview of diversity and phylogeny as they have figured into the evolution of the Asteroidea from Paleozoic to the living fauna. Living post-Paleozoic asteroids, the Neoasteroidea, are morphologically separate from those in the Paleozoic. Early Paleozoic asteroid faunas were diverse and displayed morphology that foreshadowed later living taxa. Preservation presents significant difficulties, but fossil occurrence and current accounts suggests a diverse Paleozoic fauna, which underwent extinction around the Permian-Triassic interval was followed by re-diversification of at least one surviving lineage. Ongoing phylogenetic classification debates include the status of the Paxillosida and the Concentricycloidea. Fossil and molecular evidence has been and continues to be part of the ongoing evolution of asteroid phylogenetic research. The modern lineages of asteroids include the Valvatacea, the Forcipulatacea, the Spinlosida, and the Velatida. We present an overview of diversity in these taxa, as well as brief notes on broader significance, ecology, and functional morphology of each. Although much asteroid taxonomy is stable, many new taxa remain to be discovered with many new species currently awaiting description. The Goniasteridae is currently one of the most diverse families within the Asteroidea. New data from molecular phylogenetics and the advent of global biodiversity databases, such as the World Asteroidea Database (http://www.marinespecies.org/Asteroidea/) present important new springboards for understanding the global biodiversity and evolution of asteroids

Science on a Deep-Ocean Shipwreck

Author Institution: Departments of Geological Sciences and Zoology, Museum of Biological Diversity, The Ohio state University ; Columbus-America Discovery GroupA five-year scientific investigation of a site on the North Atlantic seafloor, 270 km off Cape Fear, NC, at a depth of 2,200 m, was undertaken in conjunction with recovery operations on a nineteenth-century steamship (SS Central America which sank in an 1857 hurricane while carrying passengers and cargo en route to New York from the California gold fields). Activities in the disciplines of oceanography, marine geology, marine biology, materials science, and undersea archaeology were undertaken with the tele-directed submersible robot, Nemo. The study included field observations at the site (recorded in over 3,000 hours of videotape and 25,000 still photographs), examination of hundreds of deep-ocean specimens and artifacts, and analysis of several experiments deployed on the seafloor. Resting on a gentle slope of the Blake Ridge, the shipwreck environment was cold, lightless, oxygen-rich, and flushed by moderate currents. The sediments were a foraminiferal-pteropod ooze, deposited at a slow rate (1.7 cm/1,000 years). A diverse community of errant and sessile benthic invertebrates and benthopelagic fishes colonized the shipwreck deriving from it food, cover, and a place of attachment. This deep-ocean oasis supported a greater variety and concentration of animal life than did the surrounding ooze habitat. The timbers of the shipwreck were degraded by woodboring bivalves. The iron machinery was extensively corroded and mobilized into flow structures (rusticles) by iron-oxidizing bacteria. Passenger luggage recovered from the shipwreck contained artifacts which provided insight about the life styles of the voyagers during the Gold Rush. This project demonstrated that a holistic approach to a deep-ocean site of historic importance can provide understandings of the interrelated processes which affect cultural deposits on the abyssal seafloor and the marine life that they foster

Post-larval development in deep-sea echinoderms

The post-larval phase is an essential period in the life history of marine invertebrates; vulnerable to high mortality, it ultimately influences the distribution and abundance of adult populations. The post metamorphic ontogenesis of thirty species of deep-sea echinoderms, belonging to three classes (Ophiuroidea, Asteroidea and Echinoidea), is described using scanning electron microscopy. The life history of Ophiocten gracilis is also examined as a case study for future research on post-larval organisms. The analysis of development in ophiuroids reveals that species can be identified from a very early post metamorphic stage, even in congeneric species, contrary to the findings of other authors. The ontogeny of homologous structures is similar within related groups, but may give rise to different adult structures indifferent taxa. The mouth papillae within the ophiurids are serially homologous, originating from the jaw, but the fourth mouth papilla may have a different origin. In the families Ophiactidae, Ophiacanthidae and Amphilepididae examined, the mouth papillae have different origins, as, for instance, the adoral shieldspine or tentacle scale. Data on the post-larval development of Ophiura affinis suggest that this species is more closely related to the genus Ophiocten and a change in the generic status is proposed. Ophiocten gracilis is a bathyal brittle star occurring on both sides of the North Atlantic and its life history is studied in the eastern side of the North Atlantic. In this area, O. gracilis spawns in February/March of each year producing a large number of eggs. Fecundity is estimated to be around 40,000 eggs/ind, with the population of the Hebridean Slope being able to produce probably up to 16 million eggs/m2. Post-larvae start settling in May and numbers settling reached over 3,200 post-larvae/m2. The settling speed of post-larvae in the water column is estimated to be around 500 m/day, settling faster in warmer than colder water. Settling speeds appear to be similar for post-larvae ranging from 0.6 to 0.9 mm in disk diameter. Size at settlement is around 0.6 mm in disk diameter and 5-6 arm segments. The settlement of post-larval O. gracilis on the bottom of the Hebridean Slope also represented a considerable fraction of the particulate organic carbon (POC) flux in the area, reaching over 7% of the total daily flux. This is likely to have a considerable impact in the benthic community as competition and predation and as an additional food source for demersal and benthic organisms. The occurrence of post-larvae of O. gracilis in sediment traps also represented a large problem for POC flux measurements, with ophiuroids consuming part of the flux. In future works with sediment traps, such errors must be taken into account and ophiuroids must be included in the total POC flux. The deep-sea juvenile asteroids of the NE Atlantic could be distinguished to species level from a very early stage of development. The ontogenesis of Porcellanaster ceruleus shows that this species is likely to undergo a shift in habitat and diet during the juvenile phase. This is evidenced by the appearance of the epiproctal cone, the changing of the furrow and apical spines, the early development of the cribriform organ adjacent to the madreporite and the appearance of sediment in the stomach. P. ceruleus is probably a predator on meiofauna and small macrofaunal organisms during the early stages of life, changing to a burrowed life style ingesting sediment particles. Most juvenile sea stars analysed during the present study showed wider bathymetric distribution than their adult counterparts, suggesting that events occurring during the early stages of life are important for the maintenance of the local population structure and diversity in the deep NE Atlantic.The post-metamorphic development of three deep-sea spatangoid echinoids is very similar, but the morphology and formation of fascioles facilitate the distinction of the species examined. Whereas in Hemiaster expergitus and Spatangus raschi the fascioles present in the post-larvae develop to form the adult fascioles, in Brissopsis lyrifera post-larvae there is a juvenile fasciole, which disappears during ontogenesis giving way to the adult fascioles. The function of the juvenile fasciole is unknown in B.lyrifera. The development of the periproct in all spatangoids examined is similar to that described by other authors, with the periproct being initially endocyclic and migrating towards the rear of the animal as development progresses. Post-larvae of the genus Echinus could not be separated into different species, which may be linked to the recent diversification of the genus in the North Atlantic. The widespread settlement of echinoderm post-larvae reported in the present thesis and in other works is thought to have been very important for the colonization of the deep-sea through the supply of stages to deeper areas and selection of pressure adapted animals and subsequent speciation

Estudio de los Equinodermos Antárticos del Mar de Bellingshausen

El Mar de Bellingshausen (MB) es el tercer mar en importancia en el Océano Antártico pero debido a las condiciones extremas de hielo es una de las zonas de la Antártida menos estudiada. Las campañas antárticas Bentart 2003 y Bentart 2006, cuyo objetivo es el estudio del bentos en la Antártida del Oeste, vienen a suplir estas carencias de conocimientos en esta zona. Y con este estudio se viene a completar el conocimiento sobre los equinodermos que habitan este mar. Los objetivos de la presente memoria son completar los registros de especies de equinodermos en el Mar de Bellingshausen, caracterizar y describir la taxocenosis de equinodermos en este mar El material estudiado procede de las campañas Bentart 2003 y 2006, en las que se emplearon diferentes artes de muestreo bentónico. Se tomaron muestras de sedimento y se hicieron muestreos con roseta oceanográfica y CTD para obtener datos de variables ambientales. Las muestras de bentos obtenidas se procesaron para su posterior estudio en el Laboratorio de Estudio de Equinodermos del Departamento de Biología Animal de la Universidad de Málaga. Los equinodermos fueron determinados mediante el uso de claves, utilizando lupa binocular, microscopio óptico y electrónico. Algunas estructuras necesarias para la determinación taxonómica necesitaron un procesado previo. Con los datos de número de ejemplares se realizaron análisis que incluyeron el cálculo de índices de abundancia, de riqueza específica y de ocurrencia. Se realizaron análisis de clasificación y de ordenación. Se han determinado 5510 ejemplares de equinodermos, pertenecientes a 126 especies que sumadas a las que se conocían en esta zona, dan un total de 167 especies de este filo para el Mar de Bellingshausen. Se describe una especie nueva para la ciencia además de otras 7 que están en proceso de estudio como probables especies nuevas para la ciencia, se aportan 24 citas nuevas de equinodermos para el MB y se amplía el rango batimétrico de 22 especies. La riqueza específica de equinodermos de este mar, lo convierten en el segundo mar antártico más rico detrás del Mar de Weddell. La comunidad de equinodermos del MB está compuesta por una riqueza específica del 33% de la Clase Asteroidea, 26% de la Clase Ophiuroidea, 24% de la Clase Holothuroidea, 14% de la Clase Echinoidea y 3% de la Clase Crinoidea. El análisis de clasificación nos muestra que los equinodermos se estructuran en tres comunidades diferenciadas: la de la parte interna del Mar de Belllingshausen, la de Isla de Pedro I y la de la zona de Bahía Margarita. El análisis de ordenación por su parte nos lleva a concluir que esta estructuración de la comunidad viene influida por la profundidad, y por el tipo de sedimento. Siendo el tipo de sedimento (su granulometría) un factor muy importante, que además viene determinado por los procesos de crecimiento y decrecimiento de la plataforma de hielo y el arrastre de éste sobre los fondos. Siendo a su vez éste, un proceso que se da desde las épocas glaciales e interglaciales y que se repite a menor escala año tras año debido a la estacionalidad que existe en el Continente Antártico

Estudio de los Equinodermos Antárticos del Mar de Bellingshausen

El Mar de Bellingshausen (MB) es el tercer mar en importancia en el Océano Antártico pero debido a las condiciones extremas de hielo es una de las zonas de la Antártida menos estudiada. Las campañas antárticas Bentart 2003 y Bentart 2006, cuyo objetivo es el estudio del bentos en la Antártida del Oeste, vienen a suplir estas carencias de conocimientos en esta zona. Y con este estudio se viene a completar el conocimiento sobre los equinodermos que habitan este mar. Los objetivos de la presente memoria son completar los registros de especies de equinodermos en el Mar de Bellingshausen, caracterizar y describir la taxocenosis de equinodermos en este mar El material estudiado procede de las campañas Bentart 2003 y 2006, en las que se emplearon diferentes artes de muestreo bentónico. Se tomaron muestras de sedimento y se hicieron muestreos con roseta oceanográfica y CTD para obtener datos de variables ambientales. Las muestras de bentos obtenidas se procesaron para su posterior estudio en el Laboratorio de Estudio de Equinodermos del Departamento de Biología Animal de la Universidad de Málaga. Los equinodermos fueron determinados mediante el uso de claves, utilizando lupa binocular, microscopio óptico y electrónico. Algunas estructuras necesarias para la determinación taxonómica necesitaron un procesado previo. Con los datos de número de ejemplares se realizaron análisis que incluyeron el cálculo de índices de abundancia, de riqueza específica y de ocurrencia. Se realizaron análisis de clasificación y de ordenación. Se han determinado 5510 ejemplares de equinodermos, pertenecientes a 126 especies que sumadas a las que se conocían en esta zona, dan un total de 167 especies de este filo para el Mar de Bellingshausen. Se describe una especie nueva para la ciencia además de otras 7 que están en proceso de estudio como probables especies nuevas para la ciencia, se aportan 24 citas nuevas de equinodermos para el MB y se amplía el rango batimétrico de 22 especies. La riqueza específica de equinodermos de este mar, lo convierten en el segundo mar antártico más rico detrás del Mar de Weddell. La comunidad de equinodermos del MB está compuesta por una riqueza específica del 33% de la Clase Asteroidea, 26% de la Clase Ophiuroidea, 24% de la Clase Holothuroidea, 14% de la Clase Echinoidea y 3% de la Clase Crinoidea. El análisis de clasificación nos muestra que los equinodermos se estructuran en tres comunidades diferenciadas: la de la parte interna del Mar de Belllingshausen, la de Isla de Pedro I y la de la zona de Bahía Margarita. El análisis de ordenación por su parte nos lleva a concluir que esta estructuración de la comunidad viene influida por la profundidad, y por el tipo de sedimento. Siendo el tipo de sedimento (su granulometría) un factor muy importante, que además viene determinado por los procesos de crecimiento y decrecimiento de la plataforma de hielo y el arrastre de éste sobre los fondos. Siendo a su vez éste, un proceso que se da desde las épocas glaciales e interglaciales y que se repite a menor escala año tras año debido a la estacionalidad que existe en el Continente Antártico