Global ETD Search
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Showing 1 to 20 of 45 for “"Polychaetes"”.
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Distribution and abundance of soft-sediment intertidal Polychaetes
Polychaetes are important components of the intertidal sandflat community in Lawson’s Flat, Dillon Beach, California. Little is known about the factors that control the relative abundance of these species. In view of the extensive evidence of the importance of interactions between component species …
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Observations on the reproductive morphology of some California spionid polychaetes
This study considers the morphology of the sperm, nephridia, seminal receptacles, and gonads among a number of California spionid species. The data collected provide support for the general observation of other workers.
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Ocean acidification and its effects upon fitness in nereidid polychaetes
… skeletons (Orr et al., 2005).Using semelparous polychaetes, Platynereis dumerilii and Alitta succinea, it is shown that when exposed to pH levels forecasted to occur by 2100 (pH 7.8) survival, development, reproductive output and essential behaviours e.g. feeding and predator avoidance, are …
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Biodiversity and Biogeography of Polychaetes (Annelida): Globally and in Indonesia
… and identified 11 major biogeographic regions of polychaetes. They were: (1) North Atlantic & eastern and western parts of the Mediterranean, (2) Australia, (3) Indonesia, (4) New Zealand, (5) the Atlantic coasts of Spain and France, (6) Antarctica and the southern coast of Argentina, (7) Central …
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Convergent Evolution of Biochemical Innovations in Polychaetes: Characterizing the Molecular Basis of Bioluminescence and Venom Production
… evolved independently in different lineages of polychaetes worms (Annelida). We use an integrative approach, combining next-generation sequencing, phylogenetics and computational tools to evaluate whether these two convergent traits are the result of similar genetic and molecular mechanisms in …
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A response surface investigation of the larval tolerances of three spionid polychaetes to temperature, salinity and food concentration
… of the planktonic larvae of three spionid polychaetes to a variety of temperature and salinity combinations. Two of the spionids were morphologically very similar members of the genus Boccar.dia., B. proboscidea and B. columbiana which occupy nearly identical geographic ranges. The other …
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Taxonomy and biology of deep-sea polychaetes: temporal variability in polychaete assemblages of the abyssal NE Atlantic Ocean
… the growth and development of deposit feeding polychaetes. However, not all elements of the polychaete community showed a response (e.g. the Paraonidae). At the species level, the most abundant cirratulid and spionid species not always appear to respond in the same way as the family. Only …
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The relationship between sediment composition and infaunal polychaete communities along the southern coast of Namibia
… examined whether a selected group of organisms (polychaetes) could provide the same level of information regarding community structure, as the entire fauna, at a number of taxonomic resolutions. A total of 44 samples were collected by De Beers Marine (Pty) Ltd in 1999 off the southern coast of …
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Red Sea Polychaetes from the Gulf of Elat (Aqaba) : a contribution to the knowledge of the Polychaeta fauna and the environmental conditions which affects its distribution
A study of 50 samples of Polychaeta mainly from a northern profile (0.5 - 550 m) and down to 800 m, reveals that the fauna is characterised by extremely small specimens and a great taxonomic divergence. Techniques of handling minute specimens are described, together with 21 new species, including …
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Sediment-associated cues for larval settlement of Polydora cornuta and Streblospio benedicti (Polychaeta, Spionidae)
Patchy distribution of infaunal polychaetes may result from active site selection of larvae guided by sediment associated bacterial cues. This hypothesis was tested in still water laboratory settlement assays with and without choice option for larvae of two spionid polychaetes with indirect …
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The ecological role of feeding disturbances of the Atlantic horseshoe crab, Limulus polyphemus
… resulted in significant increase in predatory polychaetes in both years, although there were no significant trends observed in abundance of total infauna or deposit feeding polychaetes and oligochaetes. On the other hand, bivalve, Macoma balthica, abundance and biomass were significantly higher …
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The functional morphology of Axiothella rubrocinta (Johnson)
<p>The family Maldanidae is a group of sedentary polychaetes having a cylindrical body with elongate, but relatively few segments. The prostomium has a dorsal pair of nuchal organs and may have eye-spots ventrally; true appendages are absent. The mouth opens ventrally on the peristomium and has an …
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Nutritional limitation in populations of the Norway lobster, Nephrops norvegicus (L.) in the Firth of Clyde, Scotland
… of crustaceans, molluscs, and to a lesser extent polychaetes and echinoderms. The proportion of bivalves was higher in the diet of N. norvegicus from south of Little Cumbrae than in the diet of N. norvegicus from south of Ailsa Craig which contained larger proportions of crustaceans and …
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Ecology of Manayunkia speciosa
… flow forces (shear stress) required to dislodge polychaetes from substrates on which they are found in the Klamath River, and 3) to compare experimentally determined shear stresses with those found in typical macrohabitats containing <italic>M. speciosa</italic>. Results from the invertebrate …
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Conservation of polychaete biodiversity within the Port Stephens-Great Lakes Marine Park
… of biodiversity assessment and conservation. Polychaetes were used as they can comprise over one-third of species of benthic infaunal assemblages, they are the most frequent and abundant marine metazoans in benthic environments, and they are a reliable surrogate for other macrobenthic taxa. …
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Variação temporal da macrofauna bentônica sublitoral da praia da Urca (RJ) após a ocorrência de ressacas, com ênfase na fauna de anelídeos poliquetas
… most representative taxonomic groups found were polychaetes and crustaceans. Evaluating the response of the role community after the storms, it did not show a strong variation, probably due to the different responses of each group separately. Lower densities of polychaetes were registered after …
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The larval development of Pinnixa Longpipes (Lockington, 1877) (Brachyura: Pinnotheridae), reared in the laboratory
… species has occasionally been found with other polychaetes, including Pectinaria and Pista. According to Schmitt et al (1973) Pinnixa longpies range from Tomales Bay to Laguna Beach in California. There are no published accounts regarding the biology of this commensal crab.</p><p>The present …
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Do microbial or biochemical settlement cues on the sediment surface mediate larval settlement of Polydora cornuta and Streblospio benedicti (Polychaeta, Spionidae)?
Distinctive, patchy abundance patterns of spionid polychaetes i.e. Polydora cornuta and Streblospio benedicti with indirect larval development were found in sediments of tidal flats in the German Wadden Sea. These patterns were not explicable through grain size or other sediment parameters. This …
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Ecological impacts of shrimp trawling on juveniles of selected benthic fish species in the southwestern Gulf of Maine
… of trawling on its trophic ecology. Ampharetid polychaetes, other polychaetes, amphipods, bivalves and cyclopoid copepods were the dominant prey taxa. These taxa were also abundant in the environment.</p><p>A number of recommendations were proposed from these results on how such studies could …
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Mitochondrial genomics and northwestern Atlantic population genetics of marine annelids
… whole mitochondrial genome sequencing of two polychaetes (the deep-sea tubeworm Riftia pachyptila and the intertidal bamboo worm Clymenella torquata) supports the placement of leeches and oligochaetes within the polychaete radiation, in keeping with molecular evidence and morphological …
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