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R. S. K. Barnes - One of the best experts on this subject based on the ideXlab platform.
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The circatidal rhythm of the estuarine gastropod Hydrobia ulvae (Gastropoda: Hydrobiidae)
Biological Journal of the Linnean Society, 2010Co-Authors: Sónia Vieira, R. S. K. Barnes, Helena Coelho, Rita Nolasco, João Serôdio, Henrique QueirogaAbstract:Intertidal animals display a suite of cyclic behaviours that evolved as adaptations to the predictable cycle of inundation and exposure. In estuarine habitats, mud snails from the genus Hydrobia are among the most abundant grazers, and have received considerable attention with respect to the behavioural mechanisms mediating locomotion, dispersal, and feeding, although the nature of the control of these processes has remained elusive. In particular, it is not clear whether endogenous activity patterns are related to periodic changes of microphytobenthos biomass at the sediment surface, or whether they are timed to the tidal cycle at all. In the present study, we address the crawling activity of Hydrobia ulvae under constant conditions, as well as the effects of individual size and previous short-term exposure to tides of different range, by recording immersed individual snails under constant dark conditions. We show that the species displays an overt circatidal pattern of crawling, with activity peaks around high water, and that the start of inundation may act as an entrainment agent of the rhythm. Moreover, the results obtained indicate that smaller snails display higher levels of activity, although neither the size nor previous in situ influence of tidal range has an effect on the period and on the amplitude of the rhythm. These findings suggest that fluctuations of microphytobenthos biomass are not a sufficiently strong selective pressure to have shaped locomotor activity in H. ulvae. Moreover, feeding of H. ulvae should take place mostly during high water and be independent of periodic fluctuations of microphytobenthos biomass at the surface of the sediment. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100, 439–450.
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Interspecific competition and rarity in mudsnails: feeding interactions between and within Hydrobia acuta neglecta and sympatric Hydrobia species
Aquatic Conservation: Marine and Freshwater Ecosystems, 2005Co-Authors: R. S. K. BarnesAbstract:1. Using production of faecal pellets as a proxy for feeding rate, possible reciprocal effects of the widespread and abundant mudsnails Hydrobia ulvae and Hydrobia ventrosa on the rare Hydrobia acuta neglecta were investigated under the sea-water salinity conditions in which all three species occur naturally in East Anglia, UK. 2. Over a density range equivalent to 1000–34 000 m−2, H. acuta and H. ventrosa (though not H. ulvae) at some point displayed an intraspecific reduction in egestion with increase in density. For H. acuta, every 5000 extra snails above a threshold of 16 000 m−2 reduced egestion by up to 8%; and for H. ventrosa, every 5000 extra snails above a threshold of 8000 m−2 reduced egestion by an average 7%. 3. Keeping the density of one test species constant at 4000 m−2 whilst varying that of a sympatric one from 0 up to 30 000 m−2 indicates that H. ulvae has a marked effect on H. acuta at all densities, decreasing its egestion by 10% for every 5000 m−2H. ulvae also present, but that H. acuta has no such reciprocal effect on H. ulvae. H. ventrosa had no effect on egestion in H. acuta, although H. acuta did have some minor effect on H. ventrosa, on average decreasing its egestion by 3% for every 5000 m−2H. acuta present. 4. The intensity of intraspecific competition within H. acuta, therefore, exceeds that exerted on H. acuta by H. ventrosa, and likewise intraspecific effects within H. ventrosa generally outweigh any interspecific effect from H. acuta. The effect of H. ulvae on H. acuta, however, exceeds that intraspecifically within H. acuta. 5. These results are discussed in relation to the rarity of H. acuta neglecta. Copyright © 2005 John Wiley & Sons, Ltd.
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Feeding rates of continually submerged Hydrobia ulvae vary during the daylight hours
Journal of the Marine Biological Association of the United Kingdom, 2003Co-Authors: R. S. K. BarnesAbstract:Feeding, as estimated by egestion rate, in coastal epibenthic mud snails Hydrobia ulvae living continually submerged in lagoon-like conditions varies significantly with time of day. Both in the field and in the laboratory, egestion rate is maximal around mid-day and minimal at twilight. This variation, here ranging in magnitude from mean lows of some nine faecal pellets h −1 to highs of 34 h −1 , is consonant with likely rhythms of availability and productivity of their microphytobenthic food.
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Breeding, recruitment and survival in a mixed intertidal population of the mudsnails Hydrobia ulvae and H. neglecta
Journal of the Marine Biological Association of the United Kingdom, 1996Co-Authors: R. S. K. BarnesAbstract:Breeding and population statistics were assessed from February 1993 to September 1995 in a mixed population of the mudsnails Hydrobia neglecta and H. ulvae in the intertidal zone of a macrotidal bay on the Atlantic coast of Brittany, France. The biology of H. neglecta in the mixed population was identical to that found earlier for the same species when living allopatrically elsewhere in the bay, and was also that generally characterizing directly-developing species of Hydrobia that occur in coastal lagoons. The population of the larviparous H. ulvae also showed various features otherwise typifying lagoonal populations of this species: very high juvenile mortality, repeated failure of whole cohorts to recruit, and an age structure dominated by large and relatively old individuals. The number of eggs per capsule was normal for an intertidal H. ulvae population but the number of capsules laid was remarkably low. Why both species should behave in this intertidal marine habitat as if it were lagoonal is unknown. The failure of the cohorts of H. ulvae deriving from spring eggs in the bay may help explain why the majority of lagoonal populations of this species are dominated by old mudsnails and show negligible recruitment. There was no evidence of competitive displacement of H. neglecta by H. ulvae in spite of received wisdom that H. ulvae is the competitive dominant under fully marine conditions; mortality of H. ulvae was more than three times that experienced by H. neglecta regardless of age of the snails.
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Investment in eggs in lagoonal Hydrobia ventrosa and life-history strategies in north-west european Hydrobia species
Journal of the Marine Biological Association of the United Kingdom, 1994Co-Authors: R. S. K. BarnesAbstract:Expected lifetime investment in eggs and related parameters are described for a lagoonal population of Hydrobia ventrosa (Mollusca: Gastropoda) in East Anglia, UK, and these are compared with those of East Anglian lagoonal populations of H. neglecta and both lagoonal and intertidal-marine populations of H. ulvae . In contrast to an earlier study on Danish populations, which suggested that H. neglecta and H. ventrosa are at opposite ends of the hydrobiid spectrum of investment in reproduction, the order of increasing relative allocation of resources to egg production runs H. neglecta = H. ventrosa → lagoonal H. ulvae → intertidal-marine H. ulvae . That is, from the two small, short-lived, specialist lagoonal species producing few, large, directly-developing eggs, to the larger, potentially longer-lived H. ulvae that produces many small eggs which develop into veliger larvae. The lagoonal populations of all three Hydrobia species, however, are very similar to each other in terms of reproductive investment. When like cohorts are compared, in each, the annual egg weight is equal to the annual adult growth increment, and the weight of eggs produced per expected lifetime is half the adult growth increment at the time of death. These lagoonal populations are markedly dissimilar to intertidal-marine populations of H. ulvae , which produce an annual weight of eggs some 15 times the annual adult growth increment, and an expected lifetime egg weight some two-and-a-half times the adult growth increment at the time of death.
Gérard F. Blanchard - One of the best experts on this subject based on the ideXlab platform.
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differences in spatial structures between juveniles and adults of the gastropod Hydrobia ulvae on an intertidal mudflat marennes oleron bay france potentially affect estimates of local demographic processes
Journal of Sea Research, 2004Co-Authors: Pierre Richard, Jean-marc Guarini, A.-g. Haubois, A. Hemon, E. Arotcharen, Gérard F. BlanchardAbstract:Abstract Spatial structures of juvenile and adult cohorts of the gastropod Hydrobia ulvae were investigated over a surface area of several km 2 in an intertidal mudflat at the end of the recruitment period. Three cohorts (average shell lengths of 3.9±0.89 mm, 1.8±0.43 mm and 1.1±0.18 mm for cohorts I, II and III, respectively) were identified by a statistical analysis and their spatial distributions were characterised. Cohorts of juveniles (cohorts II and III) showed a patchy distribution pattern, whereas the cohort of adults (cohort I) was homogeneously distributed over the study area. These marked differences in spatial distribution of cohorts are likely to have a strong effect on estimates of local demographic processes, and hence of population dynamics.
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Differences in spatial structures between juveniles and adults of the gastropod Hydrobia ulvae on an intertidal mudflat (Marennes–Oléron Bay, France) potentially affect estimates of local demographic processes
Journal of Sea Research, 2004Co-Authors: A.-g. Haubois, Pierre Richard, Jean-marc Guarini, A. Hemon, E. Arotcharen, Gérard F. BlanchardAbstract:Abstract Spatial structures of juvenile and adult cohorts of the gastropod Hydrobia ulvae were investigated over a surface area of several km 2 in an intertidal mudflat at the end of the recruitment period. Three cohorts (average shell lengths of 3.9±0.89 mm, 1.8±0.43 mm and 1.1±0.18 mm for cohorts I, II and III, respectively) were identified by a statistical analysis and their spatial distributions were characterised. Cohorts of juveniles (cohorts II and III) showed a patchy distribution pattern, whereas the cohort of adults (cohort I) was homogeneously distributed over the study area. These marked differences in spatial distribution of cohorts are likely to have a strong effect on estimates of local demographic processes, and hence of population dynamics.
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Spatio–temporal differentiation in the population structure of Hydrobia ulvae on an intertidal mudflat (Marennes-Oléron Bay, France)
Journal of the Marine Biological Association of the UK, 2002Co-Authors: Anne-gaelle Haubois, Pierre Richard, Jean-marc Guarini, Gérard F. Blanchard, Pierre-guy SauriauAbstract:Spatio–temporal changes in density, breeding cycle, growth and population structure of Hydrobia ulvae (Gastropoda: Prosobranchia) were studied by monthly sampling of a wide bare mudflat in Marennes-Oléron Bay. Four stations, located along a cross-shore transect and characterized by different geomorphological structures, were investigated from March 2000 to February 2001. Hydrobia ulvae was mainly distributed in the upper half part of the mudflat and no individuals were found in the lower part. The breeding cycle extended from March to December and showed two annual peaks, in spring and in autumn. Three cohorts were recruited during the year and showed high growth rates during summer; the parameters of the von Bertalanffy model describing the growth curves were equal to kmax=0·47±0·5 mm month−1 and L∞=5·4±0·2 mm. The snail population had similar size–frequency structure along the transect at the beginning of the survey but summer recruitment initiated spatial differentiation. Reproduction occurred in the middle part of the mudflat but recruits mainly settled down at the upper level of the mudflat; new cohorts appeared with increasing individual densities. The middle part of the mudflat was rather dominated by adult individuals which showed large density fluctuations.
Pierre Richard - One of the best experts on this subject based on the ideXlab platform.
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Influence of environment factors on bacterial ingestion rate of the deposit-feeder Hydrobia ulvae and comparison with meiofauna
Journal of Sea Research, 2008Co-Authors: Pierre-yves Pascal, Christine Dupuy, Pierre Richard, Anne-gaelle Haubois, Nathalie NiquilAbstract:Deposit feeders are able to process a considerable volume of sediment, containing large 9 quantities of associated bacteria. However, conclusions concerning the trophic role played by 10 benthic bacteria in marine sediments are still not fully elucidated. This study deals with 11 bacterivory by the gastropod Hydrobia ulvae, one of the most abundant deposit-feeding 12 species in intertidal mudflats in Western Europe. Ingestion rates of bacteria were determined 13 during grazing experiments using 15 N pre-enriched bacteria. Grazing experiments were 14 performed in order to measure effects of abiotic (temperature, salinity and luminosity) and 15 biotic (bacterial and algal abundances) factors on ingestion rates of bacteria by H. ulvae of an 16 intertidal mudflat (Brouage, Marennes-Oléron, France). The mean ingestion rate of bacteria 17 by H. ulvae was 1149 ngC ind-1 h-1. The general trend showed a temperature effect with an 18 optimum around 30°C, and the assimilation rate was significantly lower at 5°C. Bacterial 19 assimilation did not significantly differ between salinity 18 and salinity 31. Ingestion was the 20 same in light and in dark conditions. Results were compared with those of other grazing 21 experiments conducted simultaneously in similar conditions with two other grazers with 22 different size and feeding modes: the foraminifera Ammonia tepida and a nematode 23 community from the superficial sediment of the Brouage mudflat. Hydrobia ulvae and 24 nematodes presented a feeding behavior less influenced by environmental changes than A. tepida. Hydrobia ulvae ingested bacteria at a higher rate than smaller meiofaunal grazers and seemed to have a lower ability to selectively ingest diatoms than meiofaunal grazers.
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differences in spatial structures between juveniles and adults of the gastropod Hydrobia ulvae on an intertidal mudflat marennes oleron bay france potentially affect estimates of local demographic processes
Journal of Sea Research, 2004Co-Authors: Pierre Richard, Jean-marc Guarini, A.-g. Haubois, A. Hemon, E. Arotcharen, Gérard F. BlanchardAbstract:Abstract Spatial structures of juvenile and adult cohorts of the gastropod Hydrobia ulvae were investigated over a surface area of several km 2 in an intertidal mudflat at the end of the recruitment period. Three cohorts (average shell lengths of 3.9±0.89 mm, 1.8±0.43 mm and 1.1±0.18 mm for cohorts I, II and III, respectively) were identified by a statistical analysis and their spatial distributions were characterised. Cohorts of juveniles (cohorts II and III) showed a patchy distribution pattern, whereas the cohort of adults (cohort I) was homogeneously distributed over the study area. These marked differences in spatial distribution of cohorts are likely to have a strong effect on estimates of local demographic processes, and hence of population dynamics.
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Differences in spatial structures between juveniles and adults of the gastropod Hydrobia ulvae on an intertidal mudflat (Marennes–Oléron Bay, France) potentially affect estimates of local demographic processes
Journal of Sea Research, 2004Co-Authors: A.-g. Haubois, Pierre Richard, Jean-marc Guarini, A. Hemon, E. Arotcharen, Gérard F. BlanchardAbstract:Abstract Spatial structures of juvenile and adult cohorts of the gastropod Hydrobia ulvae were investigated over a surface area of several km 2 in an intertidal mudflat at the end of the recruitment period. Three cohorts (average shell lengths of 3.9±0.89 mm, 1.8±0.43 mm and 1.1±0.18 mm for cohorts I, II and III, respectively) were identified by a statistical analysis and their spatial distributions were characterised. Cohorts of juveniles (cohorts II and III) showed a patchy distribution pattern, whereas the cohort of adults (cohort I) was homogeneously distributed over the study area. These marked differences in spatial distribution of cohorts are likely to have a strong effect on estimates of local demographic processes, and hence of population dynamics.
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Spatio–temporal differentiation in the population structure of Hydrobia ulvae on an intertidal mudflat (Marennes-Oléron Bay, France)
Journal of the Marine Biological Association of the UK, 2002Co-Authors: Anne-gaelle Haubois, Pierre Richard, Jean-marc Guarini, Gérard F. Blanchard, Pierre-guy SauriauAbstract:Spatio–temporal changes in density, breeding cycle, growth and population structure of Hydrobia ulvae (Gastropoda: Prosobranchia) were studied by monthly sampling of a wide bare mudflat in Marennes-Oléron Bay. Four stations, located along a cross-shore transect and characterized by different geomorphological structures, were investigated from March 2000 to February 2001. Hydrobia ulvae was mainly distributed in the upper half part of the mudflat and no individuals were found in the lower part. The breeding cycle extended from March to December and showed two annual peaks, in spring and in autumn. Three cohorts were recruited during the year and showed high growth rates during summer; the parameters of the von Bertalanffy model describing the growth curves were equal to kmax=0·47±0·5 mm month−1 and L∞=5·4±0·2 mm. The snail population had similar size–frequency structure along the transect at the beginning of the survey but summer recruitment initiated spatial differentiation. Reproduction occurred in the middle part of the mudflat but recruits mainly settled down at the upper level of the mudflat; new cohorts appeared with increasing individual densities. The middle part of the mudflat was rather dominated by adult individuals which showed large density fluctuations.
A.-g. Haubois - One of the best experts on this subject based on the ideXlab platform.
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differences in spatial structures between juveniles and adults of the gastropod Hydrobia ulvae on an intertidal mudflat marennes oleron bay france potentially affect estimates of local demographic processes
Journal of Sea Research, 2004Co-Authors: Pierre Richard, Jean-marc Guarini, A.-g. Haubois, A. Hemon, E. Arotcharen, Gérard F. BlanchardAbstract:Abstract Spatial structures of juvenile and adult cohorts of the gastropod Hydrobia ulvae were investigated over a surface area of several km 2 in an intertidal mudflat at the end of the recruitment period. Three cohorts (average shell lengths of 3.9±0.89 mm, 1.8±0.43 mm and 1.1±0.18 mm for cohorts I, II and III, respectively) were identified by a statistical analysis and their spatial distributions were characterised. Cohorts of juveniles (cohorts II and III) showed a patchy distribution pattern, whereas the cohort of adults (cohort I) was homogeneously distributed over the study area. These marked differences in spatial distribution of cohorts are likely to have a strong effect on estimates of local demographic processes, and hence of population dynamics.
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Differences in spatial structures between juveniles and adults of the gastropod Hydrobia ulvae on an intertidal mudflat (Marennes–Oléron Bay, France) potentially affect estimates of local demographic processes
Journal of Sea Research, 2004Co-Authors: A.-g. Haubois, Pierre Richard, Jean-marc Guarini, A. Hemon, E. Arotcharen, Gérard F. BlanchardAbstract:Abstract Spatial structures of juvenile and adult cohorts of the gastropod Hydrobia ulvae were investigated over a surface area of several km 2 in an intertidal mudflat at the end of the recruitment period. Three cohorts (average shell lengths of 3.9±0.89 mm, 1.8±0.43 mm and 1.1±0.18 mm for cohorts I, II and III, respectively) were identified by a statistical analysis and their spatial distributions were characterised. Cohorts of juveniles (cohorts II and III) showed a patchy distribution pattern, whereas the cohort of adults (cohort I) was homogeneously distributed over the study area. These marked differences in spatial distribution of cohorts are likely to have a strong effect on estimates of local demographic processes, and hence of population dynamics.
B. Bauer - One of the best experts on this subject based on the ideXlab platform.
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Toxico-kinetic and -dynamic aspects of TBT-induced imposex in Hydrobia ulvae compared with intersex in Littorina littorea (Gastropoda, Prosobranchia)
Aspects of Littorinid Biology, 1998Co-Authors: Ulrike Schulte-oehlmann, P Fioroni, B. Bauer, Jörg Oehlmann, U.-s. LefflerAbstract:A short description of the imposex condition in Hydrobia ulvae is presented. In this species four different imposex stages with two types of development were identified. In laboratory experiments the mud snail accumulates TBT in a time and concentration-dependent manner. Increasing biological indices e.g. VDSI (vas deferens sequence index), female penis length (FPL) and the imposex incidence are significantly correlated with increasing TBT body burden. The percentage of sterile females depends on the TBT contamination of sediments. An interspecific comparison of the mud snail H. ulvae and the periwinkle Littorina littorea elucidates that the mud snail is the more sensitive species at lower environmental TBT concentrations.
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Imposex and reproductive failure in Hydrobia ulvae (Gastropoda: Prosobranchia)
Marine Biology, 1997Co-Authors: Ulrike Schulte-oehlmann, P Fioroni, Jörg Oehlmann, B. BauerAbstract:Hydrobia ulvae specimens collected from 16 stations along the German North Sea and Baltic coasts exhibited imposex (occurrence of male parts in addition to the female genital system). For the purposes of comparison, a description of both the male and unaffected female genital systems is presented. Four different imposex stages with two types of development were identified and documented with scanning electron micrographs for the first time. The percentage of imposex-affected females (an average over all the localities sampled) was about 44.3%, and 12.9% were definitively sterilized. The phenomenon of sex change was not observed. The vas deferens sequence index, imposex incidence, percentage of sterilized females and the average female penis length are recommended as biological effect monitoring parameters in response to tributyltin pollution.