18 research outputs found

    Status of Sea Urchin Resources in the East Coast of Borneo

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    Sea urchins are marine benthos that live in different habitats available at shallow and deep waters. In Malaysia, Sabah is the only state that exploits sea urchins without knowing the status of natural stocks. This study identified the sea urchin species diversity at shallow subtidal zones in east coast of Borneo which is part of the Coral Triangle. Belt transects were deployed to quantify the species composition and qualitative observations on the habitat types were also noted. Simultaneously, documentation of species available in several wet markets was gathered through impromptu conversation with the sellers. In this study, a total of 10 species of sea urchin were recorded from 18 sampling sites, namely, Phyllacanthus imperialis, Diadema setosum, D. savignyi, Echinothrix calamaris, Mespilia globulus, Salmacis sphaeroides, Echinometra mathaei, Pseudoboletia maculata, Toxopneustes pileolus, and Tripneustes gratilla. The most dominant one that showed a wide distribution was D. setosum. Three species are new records for Malaysia. Among the study sites, Semporna district showed the highest species number. Our findings illustrate that shallow waters on the eastern part of Borneo support high diversity of sea urchin resources. Future study should explore the sea urchin diversity at deeper waters and also on the west coast of Sabah

    Systematic comparison and reconstruction of sea urchin (Echinoidea) internal anatomy: a novel approach using magnetic resonance imaging

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    <p>Abstract</p> <p>Background</p> <p>Traditional comparative morphological analyses and subsequent three-dimensional reconstructions suffer from a number of drawbacks. This is particularly evident in the case of soft tissue studies that are technically demanding, time-consuming, and often prone to produce artefacts. These problems can partly be overcome by employing non-invasive, destruction-free imaging techniques, in particular micro-computed tomography or magnetic resonance imaging.</p> <p>Results</p> <p>Here, we employed high-field magnetic resonance imaging techniques to gather numerous data from members of a major marine invertebrate taxon, the sea urchins (Echinoidea). For this model study, 13 of the 14 currently recognized high-ranking subtaxa (orders) of this group of animals were analyzed. Based on the acquired datasets, interactive three-dimensional models were assembled. Our analyses reveal that selected soft tissue characters can even be used for phylogenetic inferences in sea urchins, as exemplified by differences in the size and shape of the gastric caecum found in the Irregularia.</p> <p>Conclusion</p> <p>The main focus of our investigation was to explore the possibility to systematically visualize the internal anatomy of echinoids obtained from various museum collections. We show that, in contrast to classical preparative procedures, magnetic resonance imaging can give rapid, destruction-free access to morphological data from numerous specimens, thus extending the range of techniques available for comparative studies of invertebrate morphology.</p

    A Comparison of Benthic Habitats and Faunas Between the Miami Terrace (Proposed Calypso Pipeline Site) and the Pourtales Terrace (Coral Habitat of Particular Concern)

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    Quantitative photographs of benthic communities at two northern Miami Terrace sites, originally investigated as part of an environmental impact survey in advance of the proposed Calypso pipeline, and two Pourtalès Terrace sites, investigated as part of an exploration of deep-sea coral and sponge ecosystems (DSCEs) within the Pourtalès Terrace Deep-water Coral Habitat Area of Particular Concern (CHAPC), were reanalyzed and compared for similarities and differences. Both terraces are part of an elongated lithified platform that parallels the southeastern Florida coast at depths averaging between 250 and 450 m. Although both sites have similar geological origins and lie under the Florida Current, previous work has suggested that the two terraces support different benthic faunas. Images from 28 phototransects from the two terraces were condensed into two depth bins of 250-300 m and 450-550 m. Distributions of taxa compared among individual sites were depth driven, whereas distributions of taxa between the northern Miami Terrace and Pourtalès Terrace appeared to be driven by geological features, as sites at similar depths had different communities and densities, with the only distinguishing variables being location and geologic features. Results indicate that location is the driving factor contributing to differences in deep-water benthic communities between the two terraces. Depth bin 450-550 m was dominated on the Miami Terrace by hard substrates supporting octocorals (Pseudodrifa nigra, Primnoidae, Keratoisis sp., and Anthomastus sp.), anemones, and sponges (mainly Phakellia sp.) and on the Pourtalès Terrace by hard substrates and coral rubble supporting Paramuricea unid sp. 3, Comatonia cristata, Plumarella sp. 2, and Astrophorina unid. sp. 4. Depth bin 250-300 m on the northern Miami Terrace was dominated by sediment substrates and supported anemones, soft corals and zoanthids, and on the Pourtalès by sediment-veneered hard bottom with Stylaster miniatus, Plumarella unid sp., Hydroida unid sp., and Isididae unid sp. 2. The relationships between depth, location and geomorphology may be useful in designing future benthic mapping projects. In addition, species densities and protection statuses can aid future community assessments between protected habitats and non-protected habitats to measure the effectiveness and management strategies of deep-water marine protected areas. The relationships revealed by this study can be used to support the management of the Miami Terrace, Pourtalès Terrace, and other sites to conserve deep-water coral environments

    Davidson Seamount Taxonomic Guide

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    Davidson Seamount is one of the largest seamounts in U.S. waters and the first to be characterized as a “seamount.” In 2002 and 2006, the Monterey Bay National Marine Sanctuary (MBNMS) led two multi-institutional expeditions to characterize the geology and natural history of Davidson Seamount. Results from these expeditions to Davidson Seamount are adding to the scientific knowledge of seamounts, including the discovery of new species. In November 2008, the MBNMS boundary was expanded to include the Davidson Seamount. In addition, a management plan for Davidson Seamount was created to develop resource protection, education, and research strategies for the area. The purpose of this taxonomic guide is to create an inventory of benthic and mid-water organisms observed at the Davidson Seamount to provide a baseline taxonomic characterization. At least 237 taxa were observed and are presented in this guide; including 15 new or undescribed species (8 sponges, 3 corals, 1 ctenophore, 1 nudibranch, 1 polychaete, 1 tunicate) recently or currently being described by taxonomic experts. This is the first taxonomic guide to Davidson Seamount, and is intended to be revised in the future as we learn more about the seamount and the organisms that live there. (PDF has 145 pages.

    M.A.P.S. Digest, vol.10 no.5 (May 1987)

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    https://ir.uiowa.edu/midamericapaleo/1079/thumbnail.jp

    New Zealand Echinoderms

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    1. The Direct Development of a New Zealand Ophiuroid || 2. Echinoderms from the Subantarctic Islands of New Zealand: Asteroidea, Ophiuroidea, and Echinoidea || 3. The Constitution and Relations of the New Zealand Echinoderm Faun || 4. Echinoderms from Southern New Zealand || 5. A Revision of the Current Theory of Echinoderm Embryology || 6. Echinoderm Embryology and the Origin of Chordates || 7. New Zealand Fossil Asterozoa: 3. Odontaster priscus sp. nov. from the Jurassic || 8. An Echinoid from the Tertiary (janjukian) of South Australia Brochopleurus Australiae sp. nov. || 9. Probable Direct Development in Some New Zealand Ophiuroids || 10. The Origin and Migrations of Australasian Echinoderm Faunas Since the Mesozoic || 11. An Upper Cretaceous Asteroid from New Zealand || 12. A Giant Heart - Urchin || 13. A Triassic Echinoid from New Zealand || 14. Sonne Off' Shore and Deep-Sea Ophiuroids from New Zealand Waters || 15. The Occurrence of Australian Echinoids in New Zealand Waters || 16. Tertiary and Recent Echinoidea of New Zealand Cidarida

    Echinoderms of Lakshadweep and their zoogeography

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    Dr. Stanley Gardiner carried out an extensive survey in the Maldives'and Minicoy Islands, the Southernmost of the Lakshadweep group of Islands. Echinoderms other than the holothurians were dealt by Bell (1902) who reported four species of starfishes from Minicoy Island. Corrections for some of the species have been given by A. M. Clark and Davies (1966). Koehlerand Vaney (1908) reported three species of holothurians from the Lakshadweep. Holothurians of Gardiner's collection was dealt in a cursory manner by Pearson (1913 1914). James (1969) recorded forty species of echinoderms from various Islands of the Lakshadweep. Naghabushanam and Rao (1972) reported 49 species of echinoderms from the Minicoy Island, the identity of some need to be checked. Miirty et al. (1979) reported the notorious starfish the crown of thorns Acanthaster planci from Minicoy Atoll. Recently Mukhopadhyay and Samanta (2983)' reported twelve species of holothurians from the Islands of Androth, Kalpeni and Minicoy

    Recovery at Morvin: SERPENT final report

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    Recovery from disturbance is poorly understood in deep water, but the extent of anthropogenic impacts is becoming increasingly well documented. We used Remotely Operated Vehicles (ROV) to visually assess the change in benthic habitat after exploratory hydrocarbon drilling disturbance around the Morvin well located at 380m depth in the Norwegian Sea.An ROV, launched directly from the rig drilling the well in 2006 was used to carry out video transects around the well before drilling and immediately after. On a return to the site three years after disturbance a larger survey was conducted with a ship-launched ROV in 2009. Transects were repeated at the disturbed area and random background transects were taken. Visible drill cuttings were mapped for each survey, and positions and counts of epibenthic invertebrate megafauna were determined, revealing a fauna dominated by Cnidaria (45% of total observations) and Porifera (33%).Immediately after disturbance a visible cuttings pile extended to over 100m from the well and megafaunal density was significantly reduced (0.07 individuals m-2) in comparison to pre-drill data (0.23 ind. m-2). Three years later the visible extent of the cuttings pile had reduced in size, reaching 60m from the well and considerably less in some headings. In comparison to background transects (0.21 ind. m-2), megafaunal density was significantly reduced on the remaining cuttings (0.04m-2), but beyond the visible disturbance there was no significant difference (0.15m-2). The investigation at this site shows a return to background densities of megafaunal organisms over a large extent of the area previously disturbed. However a central area, where the initial cuttings pile was deepest, demonstrated reduced sessile megafaunal density which persisted three years after disturbance. Elevated Barium concentration and reduced sediment grain size suggests persistence of disturbance beyond the remaining visibly impacted area which may result in changes to the infaunal communities undetectable by ROV video survey

    Structure-Property Relationships in Sea Urchin Spines and Implications for Technical Materials

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    Sea urchin spines have been studied for numerous reasons including their crystallographic and chemical composition, their aesthetic appearance and their enigmatic growth at ambient conditions. Depending on the species, sea urchins use their spines for protection against predators, for burial in the substrate, for locomotion and for withstanding wave energy by wedging into reef cervices. Hence, sea urchin spines are in most cases optimized for bearing load. This study deals with the mechanical properties of the unique spines of Heterocentrotus mamillatus, a large Indo-Pacific Echinoid. They consist as all skeletal elements of Echinoids of Mg-calcite arranged in a porous meshwork (stereom) with very little organic material incorporated (<0.5 wt%). By the overall porosity of 0.6-0.7 their density is similar to sea water and the large and thick spines are not a burden to carry. These properties make the spines of H. mamillatus a promising biomimetic role model for high performance, intelligently structured, lightweight ceramics. Since biological role models are usually a lot smaller than the technical application they inspire, the question of how properties change with an increase in size, is intimately linked to biomimetic research. In contrast to man-made materials, biological materials gain much of their mechanical performance from the elaborate structuring on many hierarchical levels. Therefore, the relation between structure and property was analysed in depth before addressing the question of scaling. Mechanical properties were tested with uniaxial compression, 3-point bending and resonance frequency damping analysis. The structure was visualized by optical microscopy, secondary scanning microscopy and computer tomography. X-ray diffraction, infrared spectroscopy, thermogravimetry and dilatometry gave insight into the crystallography and chemical composition. For scaling analyses theories of Weibull and Bažant were applied. The spines generally derive their high strength, high stiffness and exceptional damage tolerance from their construction out of >107 struts/cm3. The µm sized struts can be bent elastically, demonstrating that they are practically free of surface flaws. The struts are separated by pores which restrict crack growth and keep damage localised. The porous meshwork is covered irregularly by dense layers, the “growth layers” marking earlier growth stages. They provide the spines with additional stiffness and strength. Spines with many growth layers have a significantly higher strength and stiffness. The strength of the spines seems not to decrease significantly with increasing size, contradicting scaling theories. To test this unexpected finding, compression tests on samples with and without growth layers were conducted. A novel micro-compression test, the pin indentation was also applied. Despite the uncertainties induced by natural heterogeneities, it seems that spines of H. mamillatus counteract the size effect by adding more and denser growth layers to larger (older) spines. By this they work against the decrease in strength with increasing size. This hypothesis was confirmed by segments lacking growth layers that show a size effect
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