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Frédérique Viard - One of the best experts on this subject based on the ideXlab platform.

  • Genetic structure in native and non-native populations of the direct-developing gastropod Crepidula convexa
    Marine Biology, 2014
    Co-Authors: Abigail E. Cahill, Frédérique Viard
    Abstract:

    In many marine invertebrate species, larval development plays an important role in population connectivity and gene flow: species with direct benthic development generally show more genetic structure than those with planktonic development. We used nuclear markers (microsatellites) to determine population genetic structure of the direct-developing snail Crepidula convexa (Gastropoda: Calyptraeidae) in seven populations with 15-85 individuals each within its native range of the northwest Atlantic and compared it to Crepidula Fornicata, a congener with planktonic development. Our results are consistent with general expectations and previous work in these species with other markers: C. convexa had greater population structure and even at a regional scale shows significant isolation-by-distance, in contrast to C. Fornicata. We also genotyped a single population of C. convexa introduced to the northeastern Pacific to investigate the prediction of reduced genetic diversity following introduction (founder effect). We did not find a reduction in genetic diversity, suggesting that this non-native population may be characterized by multiple introductions. This pattern is consistent with many other introduced populations of marine invertebrates, including C. Fornicata.

  • In silico mining and characterization of 12 EST-SSRs for the invasive slipper limpet Crepidula Fornicata.
    Marine genomics, 2011
    Co-Authors: Florentine Riquet, Marion Ballenghien, Arnaud Tanguy, Frédérique Viard
    Abstract:

    Abstract In silico mining of an expressed sequence tags (ESTs) library was found to be efficient at isolating simple sequence repeats (SSRs) loci in the non-indigenous marine mollusc Crepidula Fornicata. Twelve SSR loci were developed for routine genotyping. Cross-species amplification to 8 other Crepidula species showed that the 12 loci are highly specific for C. Fornicata. Mendelian inheritance was shown for 11 of them (1 being monomorphic in the analyzed offspring array). The genetic diversity for 88 adults was found to be variable across the 12 loci (2–40 alleles, expected heterozygosity between 0.023 and 0.898) with a high overall exclusion probability of 0.99. The degree of genetic polymorphism found here is similar to that shown for 7 anonymous SSRs previously developed and here used on the same samples. This set of 12 specific loci is relevant to perform reliable population and relatedness analyses in Crepidula Fornicata.

  • Infestation of the invasive mollusc Crepidula Fornicata by the native shell borer Cliona celata: a case of high parasite load without detrimental effects
    Biological Invasions, 2011
    Co-Authors: Sabrina Le Cam, Frédérique Viard
    Abstract:

    The temporal prevalence of the widespread boring sponge Cliona celata and its effects were analysed in a population of the invasive mollusc Crepidula Fornicata. This mollusc produces extra shell material when infested with the endolithic sponge, suggesting that infestation may be detrimental for C. Fornicata growth and/or reproduction. For 37 months, size, sex, female reproductive status and sponge-infestation stage were recorded for 300 individuals sampled every month in the Bay of Morlaix (France). In the 12,049 individuals examined, the prevalence of C. celata was high with a monthly average of 43.1% of the individuals hosting the sponge. The relative proportion of heavily infested individuals generally increased over time. Nevertheless, a cyclic decrease occurred every 10 months, suggesting putative episodes of mortality of heavily infested individuals. The gregarious behaviour of the mollusc seemed to promote the high prevalence of the sponge, which may propagate through contact between neighbouring C. Fornicata individuals. Due to the sex-size relationship in protandrous C. Fornicata, females were far more infested than males. We did not find evidence for a cost of producing extra shell material on somatic growth or on female fertility, and the boring sponge is unlikely to substantially affect the sex-change patterns in C. Fornicata. The limited effects of the endolithic sponge on C. Fornicata contrasts with the documented damage to some local species, including commercially exploited shellfish, suggesting that C. Fornicata may alter the infestation dynamics in the surrounding native community. Dedicated studies are now needed to investigate the extent and mechanisms of these species interactions.

  • In silico mining and characterization of 12 EST-SSRs for the invasive slipper limpet Crepidula Fornicata
    Marine Genomics, 2011
    Co-Authors: Florentine Riquet, Marion Ballenghien, Arnaud Tanguy, Frédérique Viard
    Abstract:

    In silico mining of an expressed sequence tags (ESTs) library was found to be efficient at isolating simple sequence repeats (SSRs) loci in the non-indigenous marine mollusc Crepidula Fornicata. Twelve SSR loci were developed for routine genotyping. Cross-species amplification to 8 other Crepidula species showed that the 12 loci are highly specific for C Fornicata. Mendelian inheritance was shown for 11 of them (1 being monomorphic in the analyzed offspring array). The genetic diversity for 88 adults was found to be variable across the 12 loci (2-40 alleles, expected heterozygosity between 0.023 and 0.898) with a high overall exclusion probability of 0.99. The degree of genetic polymorphism found here is similar to that shown for 7 anonymous SSRs previously developed and here used on the same samples. This set of 12 specific loci is relevant to perform reliable population and relatedness analyses in Crepidula Fornicata. (C) 2011 Elsevier B.V. All rights reserved.

  • Experimental induction of larval metamorphosis by a naturally-produced halogenated compound (dibromomethane) in the invasive mollusc Crepidula Fornicata (L.)
    Journal of Experimental Marine Biology and Ecology, 2010
    Co-Authors: Nicolas Taris, Jan A. Pechenik, Thierry Comtet, Robin Stolba, Régis Lasbleiz, Frédérique Viard
    Abstract:

    Abstract In many marine benthic invertebrates, the larval stage is the main vector of dispersal. Selective metamorphosis of larvae into an appropriate habitat is then essential to the survival of the benthic adult, with profound implications for population dynamics. Within this context, the identification of causal external factors triggering larval metamorphosis is of primary interest. In the widely invasive marine species Crepidula Fornicata (L.), adult conditioned seawater is an effective inducer but the inducer has not yet been chemically characterized. In the present study, we experimentally tested the inductive ability of dibromomethane (DBM), a halogenated compound naturally-produced by red algae of the family Corallinaceae that co-occur with C. Fornicata in the field. Through a series of three experiments, we demonstrated that DBM effectively induces metamorphosis of C. Fornicata larvae, with a strong dose–response effect. Positive responses were observed for the four tested concentrations (5, 50, 500 and 5000 ppm), 5000 ppm being the most effective at inducing rapid metamorphosis. At this concentration, larvae became responsive at least five days before they became responsive to excess KCl, a chemical commonly used to test for competence in C. Fornicata. Whether DBM could be an effective natural inducer would require further studies to quantify DBM and other halogenated compounds in the vicinity of C. Fornicata beds, where they could influence larval behaviour even in the absence of other settlement cues.

Priscilla Decottignies - One of the best experts on this subject based on the ideXlab platform.

  • The dark side of soft tissues: Unexpected inorganic carbonate in the invasive slipper limpet Crepidula Fornicata and its implications for stable isotope interpretations.
    Rapid communications in mass spectrometry : RCM, 2018
    Co-Authors: Thibault Androuin, Priscilla Decottignies, Stanislas F. Dubois, Ewan Pelleter, Antoine Carlier
    Abstract:

    Rationale Stable isotopic analysis is extensively used in trophic ecology. Inorganic carbonates, usually originating from shell fragments, are routinely removed from samples using an acid treatment because they affect δ13 C values. However, acid treatment can also change δ15 N values. For some taxa such as molluscs, the general assumption is that acid pre-treatment is not necessary since their shell is easily dissected from soft tissues and represents the only source of inorganic carbonates. However, other sources of non-dietary carbon (e.g., intracellular inorganic carbon) enriched in13 C thus get overlooked. Methods Soft tissues (foot) of the invasive gastropod Crepidula Fornicata of different size classes were analysed for their δ13 C and δ15 N values with and without acid pre-treatment using isotope ratio mass spectrometry. In toto microscopic investigations coupled with acid treatment, scanning electron microscopy and energy-dispersive spectroscopy were used to highlight the presence of inorganic carbonate. A correction model was derived and applied to existing stable isotope data for C. Fornicata. We used both seasonal variations in δ13 C signatures and mixing model outputs to assess the error in δ13 C values. Results Acid pre-treatment had a significant effect on the stable isotope compositions of C. Fornicata foot tissue, especially on δ13 C values: isotopic differences increased with size, up to 3‰ for large females. No effect was detected for small (below ~20 mm) and motile males. In toto microscopic analysis revealed the presence of small spherules of inorganic carbonate, hence explaining the differences in δ13 C values. Mixing model outputs and seasonal variation of δ13 C values showed that untreated samples can lead to large misinterpretations about diet proportions and degree of trophic niche overlap, respectively. Conclusions Spherules of inorganic carbonate in C. Fornicata soft tissues are likely to be linked with the motility of this species and their mucus production. We recommend assessing the presence of inorganic carbonate in soft tissue of sessile gastropods.

  • Subtidal Microphytobenthos: A Secret Garden Stimulated by the Engineer Species Crepidula Fornicata
    Frontiers in Marine Science, 2018
    Co-Authors: Thibault Androuin, Priscilla Decottignies, Lubos Polerecky, Stanislas Dubois, Christine Dupuy, Cédric Hubas, Bruno Jesus, Erwan Le Gall, Martin Marzloff, Antoine Carlier
    Abstract:

    The slipper limpet Crepidula Fornicata is an emblematic invasive species along the northeast Atlantic coast. This gregarious gastropod lives in stacks of several individuals and forms extended beds in shallow subtidal areas. The effects of this engineer species on the colonized habitat can be physical (e.g., presence of hard-shell substrates with uneven topography) or biological (e.g., nutrient enrichment by direct excretion or via biodeposition). We hypothesized that through biological activity, nutrient fluxes at the sediment-water interface are enhanced, leading to stimulated primary productivity by microphytobenthos (MPB) associated with Crepidula beds. To test this fertilization hypothesis, we conducted a 10-day mesocosm experiment using C. Fornicata (live and dead) placed on top of sieved and homogenized sediment collected in situ. We used hyperspectral imaging to non-invasively map the development of MPB biomass, and to assess the potential influence of C. Fornicata and its spatial extent. Our results showed that live C. Fornicata significantly promote MPB growth through both physical and biological effects, with the biological effect dominating over the pure physical one. The highest stimulation was observed on the shells, suggesting that dissolved metabolic products excreted by C. Fornicata were likely the main factor stimulating MPB growth in our short-term experiment. Our findings provide first direct evidence that stimulation of MPB growth by the biological activity of larger benthic epifauna occurs not only in intertidal but also in shallow subtidal habitats. More research is needed to assess the contribution of this fertilization effect to the trophic functioning of subtidal benthic systems.

  • Data_Sheet_1_Subtidal Microphytobenthos: A Secret Garden Stimulated by the Engineer Species Crepidula Fornicata.docx
    2018
    Co-Authors: Thibault Androuin, Priscilla Decottignies, Lubos Polerecky, Christine Dupuy, Cédric Hubas, Bruno Jesus, Martin Marzloff, Stanislas F. Dubois, Erwan Le Gall, Antoine Carlier
    Abstract:

    The slipper limpet Crepidula Fornicata is an emblematic invasive species along the northeast Atlantic coast. This gregarious gastropod lives in stacks of several individuals and forms extended beds in shallow subtidal areas. The effects of this engineer species on the colonized habitat can be physical (e.g., presence of hard-shell substrates with uneven topography) or biological (e.g., nutrient enrichment by direct excretion or via biodeposition). We hypothesized that through biological activity, nutrient fluxes at the sediment-water interface are enhanced, leading to stimulated primary productivity by microphytobenthos (MPB) associated with Crepidula beds. To test this fertilization hypothesis, we conducted a 10-day mesocosm experiment using C. Fornicata (live and dead) placed on top of sieved and homogenized sediment collected in situ. We used hyperspectral imaging to non-invasively map the development of MPB biomass, and to assess the potential influence of C. Fornicata and its spatial extent. Our results showed that live C. Fornicata significantly promote MPB growth through both physical and biological effects, with the biological effect dominating over the pure physical one. The highest stimulation was observed on the shells, suggesting that dissolved metabolic products excreted by C. Fornicata were likely the main factor stimulating MPB growth in our short-term experiment. Our findings provide first direct evidence that stimulation of MPB growth by the biological activity of larger benthic epifauna occurs not only in intertidal but also in shallow subtidal habitats. More research is needed to assess the contribution of this fertilization effect to the trophic functioning of subtidal benthic systems.

  • Evidence that rising coastal seawater temperatures increase reproductive output of the invasive gastropod Crepidula Fornicata
    Marine Ecology Progress Series, 2011
    Co-Authors: Alexandra Valdizan, Priscilla Decottignies, Peter G. Beninger, Marianne Chantrel, Bruno Cognie
    Abstract:

    Although water temperature is thought to be an important factor in the proliferation of the invasive slipper limpet Crepidula Fornicata along the northern European Atlantic coast, evidence for this proposition is scarce. We used quantitative histology to compare the reproductive dynamics over 2 temporally-separated sexual cycles (2000−2001 and 2006−2007) from the same C. Fornicata population in Bourneuf Bay, France. Water temperature and chlorophyll (chl) a data were also analyzed in relation to historical trends and to reproductive processes. Historical temperature data show a progressive warming trend, especially since 1995, when the slipper limpet problem began to be severe. Similarly, the incidence of high chl a peaks increased markedly from 1996 onwards. Significantly higher water temperatures and more chl a peaks were found for the 2006−2007 sampling period compared to 2000−2001, and corresponded to (1) an increase in duration of brood presence, most notably the appearance of broods earlier in the year, and (2) an increase in intensity of gametogenesis in 2006−2007. These results support the hypo thesis that increased Northern European water temperatures enhance the reproductive success of C. Fornicata, both through more favourable gametogenic/brooding temperatures and through enhanced phytoplankton availability.

  • Exploitation of natural food sources by two sympatric, invasive suspension-feeders: Crassostrea gigas and Crepidula Fornicata
    Marine Ecology Progress Series, 2007
    Co-Authors: Priscilla Decottignies, Peter G. Beninger, Yves Rincé, Richard J. Robins, Pascal Riera
    Abstract:

    The natural diets of the introduced suspension-feeders Crassostrea gigas (Thunberg) and Crepidula Fornicata (L.) were determined at a mid-latitudinal oyster-farming site within their European range (Bourgneuf Bay, France). Carbon and nitrogen stable isotope deviations of Pacific oysters and slipper limpets were compared with potential food sources on 3 sampling dates (March, July and November 2003). Four end-members were assimilated by the 2 species: C3 angiosperm detritus, macroalgae-C4 plant detritus, marine phytoplankton and benthic diatoms. Given the lack of source digestibility data for suspension-feeders, and these 2 species in particular, extreme feasible combinations of relative end-member contributions were calculated according to 2 assimilation sce- narios, using either IsoSource software or a concentration-dependent model. For both Crassostrea gigas and Crepidula Fornicata, benthic and planktonic microalgae dominated diets on the 3 sampling dates. Planktonic microalgae were ingested in greater proportions than benthic species in July and November; however, benthic diatoms also formed a constant and significant part of diets in these months, and were consumed in greater proportions than planktonic species in March. Plant (espe- cially macroalgal) detritus played a major role in the diets of the 2 suspension-feeders, notably in March 2003 when it became the principal ingested source. The substantial contribution of plant detri- tus to the natural diets of these species has not previously been reported. Although Crassostrea gigas and Crepidula Fornicata showed significantly different isotopic deviations in March and July 2003, trophic niches of Crassostrea gigas and Crepidula Fornicata overlapped on all 3 sampling dates, with a greater ingestion of identical sources in November. These 2 invasive species could therefore be trophic competitors in the context of end-member supply limitation. Contrary to previous analyses conducted on these 2 species in Europe, this study reports significant dietary overlap. Ecosystem- specific diet studies of invasive species are thus necessary in order to understand trophic overlap/ competition as a function of the diversity and availability of local food sources.

Antoine Carlier - One of the best experts on this subject based on the ideXlab platform.

  • Trophic niche of the invasive gregarious species Crepidula Fornicata, in relation to ontogenic changes
    2020
    Co-Authors: Thibault Androuin, Cédric Hubas, Stanislas F. Dubois, Gwendoline Lefebvre, Fabienne Le Grand, Gauthier Schaal, Antoine Carlier
    Abstract:

    Crepidula Fornicata is a common and widespread invasive gregarious species along the European coast. Among its life-history traits, well documented ontogenic changes in behavior (i.e., motile male to sessile female) suggest a potential shift in feeding strategy across its life stages. Considering the ecological significance of this species in colonized areas, understanding how conspecifics share the trophic resource is crucial. Using fatty acids (FA) and stable isotopes (SI) as complementary trophic markers, we conducted a field survey between late winter and spring to investigate the trophic niche of three ontogenic stages of C. Fornicata that bear different sexual (male/female) and motility (motile/sessile) traits. Potential trophic sources were characterized by their pigment, FA and SI compositions and showed well discriminated compositions over the studied period. We showed that the biofilm covering C. Fornicata shells harbored a higher biomass of primary producers (i.e., chlorophytes and diatoms) than the surrounding sediment. Over the studied period, we observed a covariation between the three ontogenic stages for both FA and SI compositions which suggest that the trophic niche of C. Fornicata does not change significantly across its benthic life. During periods of low food availability, slipper limpets displayed an opportunistic suspension-feeding behaviour, relying on both fresh and detrital organic matter, likely coming from superficial sedimentary organic matter. However, during high food availability (i.e., spring phytoplankton bloom), all ontogenic stages largely benefited from this fresh supply of organic matter (pelagic diatoms in this case). The three ontogenic stages showed consistent differences in FA composition, and to a lesser extent in SI composition. These differences persist over time, as they originate from ontogenic physiological changes (differential growth rates, metabolic rate or gametogenesis) rather than diet discrepancies. This study revealed that multiple trophic markers allow high complementary to characterize organic matter as well as food partitioning between conspecific organisms.

  • The dark side of soft tissues: Unexpected inorganic carbonate in the invasive slipper limpet Crepidula Fornicata and its implications for stable isotope interpretations.
    Rapid communications in mass spectrometry : RCM, 2018
    Co-Authors: Thibault Androuin, Priscilla Decottignies, Stanislas F. Dubois, Ewan Pelleter, Antoine Carlier
    Abstract:

    Rationale Stable isotopic analysis is extensively used in trophic ecology. Inorganic carbonates, usually originating from shell fragments, are routinely removed from samples using an acid treatment because they affect δ13 C values. However, acid treatment can also change δ15 N values. For some taxa such as molluscs, the general assumption is that acid pre-treatment is not necessary since their shell is easily dissected from soft tissues and represents the only source of inorganic carbonates. However, other sources of non-dietary carbon (e.g., intracellular inorganic carbon) enriched in13 C thus get overlooked. Methods Soft tissues (foot) of the invasive gastropod Crepidula Fornicata of different size classes were analysed for their δ13 C and δ15 N values with and without acid pre-treatment using isotope ratio mass spectrometry. In toto microscopic investigations coupled with acid treatment, scanning electron microscopy and energy-dispersive spectroscopy were used to highlight the presence of inorganic carbonate. A correction model was derived and applied to existing stable isotope data for C. Fornicata. We used both seasonal variations in δ13 C signatures and mixing model outputs to assess the error in δ13 C values. Results Acid pre-treatment had a significant effect on the stable isotope compositions of C. Fornicata foot tissue, especially on δ13 C values: isotopic differences increased with size, up to 3‰ for large females. No effect was detected for small (below ~20 mm) and motile males. In toto microscopic analysis revealed the presence of small spherules of inorganic carbonate, hence explaining the differences in δ13 C values. Mixing model outputs and seasonal variation of δ13 C values showed that untreated samples can lead to large misinterpretations about diet proportions and degree of trophic niche overlap, respectively. Conclusions Spherules of inorganic carbonate in C. Fornicata soft tissues are likely to be linked with the motility of this species and their mucus production. We recommend assessing the presence of inorganic carbonate in soft tissue of sessile gastropods.

  • Subtidal Microphytobenthos: A Secret Garden Stimulated by the Engineer Species Crepidula Fornicata
    Frontiers in Marine Science, 2018
    Co-Authors: Thibault Androuin, Priscilla Decottignies, Lubos Polerecky, Stanislas Dubois, Christine Dupuy, Cédric Hubas, Bruno Jesus, Erwan Le Gall, Martin Marzloff, Antoine Carlier
    Abstract:

    The slipper limpet Crepidula Fornicata is an emblematic invasive species along the northeast Atlantic coast. This gregarious gastropod lives in stacks of several individuals and forms extended beds in shallow subtidal areas. The effects of this engineer species on the colonized habitat can be physical (e.g., presence of hard-shell substrates with uneven topography) or biological (e.g., nutrient enrichment by direct excretion or via biodeposition). We hypothesized that through biological activity, nutrient fluxes at the sediment-water interface are enhanced, leading to stimulated primary productivity by microphytobenthos (MPB) associated with Crepidula beds. To test this fertilization hypothesis, we conducted a 10-day mesocosm experiment using C. Fornicata (live and dead) placed on top of sieved and homogenized sediment collected in situ. We used hyperspectral imaging to non-invasively map the development of MPB biomass, and to assess the potential influence of C. Fornicata and its spatial extent. Our results showed that live C. Fornicata significantly promote MPB growth through both physical and biological effects, with the biological effect dominating over the pure physical one. The highest stimulation was observed on the shells, suggesting that dissolved metabolic products excreted by C. Fornicata were likely the main factor stimulating MPB growth in our short-term experiment. Our findings provide first direct evidence that stimulation of MPB growth by the biological activity of larger benthic epifauna occurs not only in intertidal but also in shallow subtidal habitats. More research is needed to assess the contribution of this fertilization effect to the trophic functioning of subtidal benthic systems.

  • Data_Sheet_1_Subtidal Microphytobenthos: A Secret Garden Stimulated by the Engineer Species Crepidula Fornicata.docx
    2018
    Co-Authors: Thibault Androuin, Priscilla Decottignies, Lubos Polerecky, Christine Dupuy, Cédric Hubas, Bruno Jesus, Martin Marzloff, Stanislas F. Dubois, Erwan Le Gall, Antoine Carlier
    Abstract:

    The slipper limpet Crepidula Fornicata is an emblematic invasive species along the northeast Atlantic coast. This gregarious gastropod lives in stacks of several individuals and forms extended beds in shallow subtidal areas. The effects of this engineer species on the colonized habitat can be physical (e.g., presence of hard-shell substrates with uneven topography) or biological (e.g., nutrient enrichment by direct excretion or via biodeposition). We hypothesized that through biological activity, nutrient fluxes at the sediment-water interface are enhanced, leading to stimulated primary productivity by microphytobenthos (MPB) associated with Crepidula beds. To test this fertilization hypothesis, we conducted a 10-day mesocosm experiment using C. Fornicata (live and dead) placed on top of sieved and homogenized sediment collected in situ. We used hyperspectral imaging to non-invasively map the development of MPB biomass, and to assess the potential influence of C. Fornicata and its spatial extent. Our results showed that live C. Fornicata significantly promote MPB growth through both physical and biological effects, with the biological effect dominating over the pure physical one. The highest stimulation was observed on the shells, suggesting that dissolved metabolic products excreted by C. Fornicata were likely the main factor stimulating MPB growth in our short-term experiment. Our findings provide first direct evidence that stimulation of MPB growth by the biological activity of larger benthic epifauna occurs not only in intertidal but also in shallow subtidal habitats. More research is needed to assess the contribution of this fertilization effect to the trophic functioning of subtidal benthic systems.

Pascal Riera - One of the best experts on this subject based on the ideXlab platform.

  • Seasonal Variations in Maternal Provisioning of Crepidula Fornicata (Gastropoda): Fatty Acid Composition of Females, Embryos and Larvae
    PLoS ONE, 2013
    Co-Authors: Fanny Leroy, Pascal Riera, Tarik Méziane, Thierry Comtet
    Abstract:

    Recruitment success of marine invertebrate populations not only depends on the number of recruits but also on their quality which affects their survival. In species characterized by a mixed development (encapsulated embryonic development and release of planktotrophic larvae), the offspring quality depends on both maternal provisioning and larval feeding. Here, we investigated potential changes of maternal provisioning over the whole reproductive period in a gastropod with a mixed development: Crepidula Fornicata. In its introduction area, C. Fornicata reproduces from February to October, which implies that both adults and larvae are exposed to different food availabilities. Maternal provisioning was assessed by measuring the fatty acid (FA) composition of females, encapsulated embryos and larvae, in February, May, July and September 2009. FA are essential resources for the development of embryos and larvae, and are key biomarkers of offspring quality. Our results showed differences in FA composition between muscles, visceral masses, and encapsulated embryos. In particular, FA composition of embryos was similar to that of the visceral mass. Seasonal variations in FA composition were observed: in the middle of the reproductive season (May and July), female tissues and embryos showed a higher proportion of polyunsaturated fatty acids and especially.3, as compared to the beginning and end of the reproductive season (February and September). This showed that through maternal provisioning the quality of C. Fornicata offspring was higher in the middle of the reproductive season. Whether this would result in an increase of recruitment success and juvenile performance would require further investigations.

  • importance of bacterivory and preferential selection toward diatoms in larvae of crepidula Fornicata l assessed by a dual stable isotope 13c 15n labeling approach
    Journal of Sea Research, 2012
    Co-Authors: Pascal Riera, Fanny Leroy, Christian Jeanthon, Frederique Edmond, Cedric Leroux, Thierry Comtet
    Abstract:

    Abstract In Europe, the gastropod Crepidula Fornicata is an invasive species characterized by a long reproductive period (from February to November). Thus, its larvae are exposed to variations in available food sources (in terms of quantity and quality). We aimed to investigate if bacteria could contribute to larval food both in presence or absence of phytoplankton, and to compare these results to seasonal variations of bacteria and phytoplankton abundances at a coastal site in the English Channel. First, ingestion of fluorescent beads of 0.5 to 2 μm diameter, showed that larvae were able to ingest particles of typical bacterial size. Then we used a dual stable isotope labeling approach which consisted in labeling a bacterial pelagic community with 15N and a diatom (Chaetoceros gracilis) culture with 13C, and supplying larvae with 15N-labeled bacteria, 13C-labeled diatoms, and both labeled sources. This technique has, to our knowledge, never been applied to invertebrate larvae. After 24 h of experiment, larvae were significantly enriched in all treatments: + 21.5‰ (∆δ13C) when supplied with diatoms, + 1364‰ (∆δ15N) when supplied with bacteria, and + 24‰ (∆δ13C) and + 135‰ (∆δ15N) when supplied with the two mixed sources. These results indicated that bacteria can contribute to the larval nutrition in C. Fornicata, even in the presence of phytoplankton. Our results however suggested that larvae of C. Fornicata preferentially used diatoms and showed that the supply of free bacteria did not alter the uptake of diatoms. Considering the seasonal variations of bacteria and phytoplankton abundances at the study site, these results suggested that bacteria may constitute a complementary resource for the larvae of C. Fornicata when phytoplankton is abundant and may become a substitute resource when phytoplankton is less available. This approach offers promising perspectives to trace food sources and assess nitrogen and carbon fluxes between planktotrophic larvae and their preys.

  • Importance of bacterivory and preferential selection toward diatoms in larvae of Crepidula Fornicata (L.) assessed by a dual stable isotope (C-13, N-15) labeling approach
    Journal of Sea Research, 2012
    Co-Authors: Fanny Leroy, Pascal Riera, Christian Jeanthon, Frederique Edmond, Cedric Leroux, Thierry Comtet
    Abstract:

    In Europe, the gastropod Crepidula Fornicata is an invasive species characterized by a long reproductive period (from February to November). Thus, its larvae are exposed to variations in available food sources (in terms of quantity and quality). We aimed to investigate if bacteria could contribute to larval food both in presence or absence of phytoplankton, and to compare these results to seasonal variations of bacteria and phytoplankton abundances at a coastal site in the English Channel. First, ingestion of fluorescent beads of 0.5 to 2 um diameter, showed that larvae were able to ingest particles of typical bacterial size. Then we used a dual stable isotope labeling approach which consisted in labeling a bacterial pelagic community with N-15 and a diatom (Chaetoceros gracilis) culture with C-13, and supplying larvae with N-15-labeled bacteria, C-13-labeled diatoms, and both labeled sources. This technique has, to our knowledge, never been applied to invertebrate larvae. After 24 h of experiment, larvae were significantly enriched in all treatments: +21.5 parts per thousand (Delta delta C-13) when supplied with diatoms, +1364 parts per thousand (Delta delta N-15) when supplied with bacteria, and +24 parts per thousand (Delta delta C-13) and +135 parts per thousand (Delta delta N-15) when supplied with the two mixed sources. These results indicated that bacteria can contribute to the larval nutrition in C. Fornicata, even in the presence of phytoplankton. Our results however suggested that larvae of C. Fornicata preferentially used diatoms and showed that the supply of free bacteria did not alter the uptake of diatoms. Considering the seasonal variations of bacteria and phytoplankton abundances at the study site, these results suggested that bacteria may constitute a complementary resource for the larvae of C. Fornicata when phytoplankton is abundant and may become a substitute resource when phytoplankton is less available. This approach offers promising perspectives to trace food sources and assess nitrogen and carbon fluxes between planktotrophic larvae and their preys. (C) 2012 Elsevier B.V. All rights reserved.

  • Exploitation of natural food sources by two sympatric, invasive suspension-feeders: Crassostrea gigas and Crepidula Fornicata
    Marine Ecology Progress Series, 2007
    Co-Authors: Priscilla Decottignies, Peter G. Beninger, Yves Rincé, Richard J. Robins, Pascal Riera
    Abstract:

    The natural diets of the introduced suspension-feeders Crassostrea gigas (Thunberg) and Crepidula Fornicata (L.) were determined at a mid-latitudinal oyster-farming site within their European range (Bourgneuf Bay, France). Carbon and nitrogen stable isotope deviations of Pacific oysters and slipper limpets were compared with potential food sources on 3 sampling dates (March, July and November 2003). Four end-members were assimilated by the 2 species: C3 angiosperm detritus, macroalgae-C4 plant detritus, marine phytoplankton and benthic diatoms. Given the lack of source digestibility data for suspension-feeders, and these 2 species in particular, extreme feasible combinations of relative end-member contributions were calculated according to 2 assimilation sce- narios, using either IsoSource software or a concentration-dependent model. For both Crassostrea gigas and Crepidula Fornicata, benthic and planktonic microalgae dominated diets on the 3 sampling dates. Planktonic microalgae were ingested in greater proportions than benthic species in July and November; however, benthic diatoms also formed a constant and significant part of diets in these months, and were consumed in greater proportions than planktonic species in March. Plant (espe- cially macroalgal) detritus played a major role in the diets of the 2 suspension-feeders, notably in March 2003 when it became the principal ingested source. The substantial contribution of plant detri- tus to the natural diets of these species has not previously been reported. Although Crassostrea gigas and Crepidula Fornicata showed significantly different isotopic deviations in March and July 2003, trophic niches of Crassostrea gigas and Crepidula Fornicata overlapped on all 3 sampling dates, with a greater ingestion of identical sources in November. These 2 invasive species could therefore be trophic competitors in the context of end-member supply limitation. Contrary to previous analyses conducted on these 2 species in Europe, this study reports significant dietary overlap. Ecosystem- specific diet studies of invasive species are thus necessary in order to understand trophic overlap/ competition as a function of the diversity and availability of local food sources.

  • δ13C versus δ15N of co-occurring molluscs within a community dominated by Crassostrea gigas and Crepidula Fornicata (Oosterschelde, The Netherlands)
    Marine Ecology Progress Series, 2002
    Co-Authors: Pascal Riera, Lucas J. Stal, J. Nieuwenhuize
    Abstract:

    The aim of this study was to investigate, by use of d13C and d15N, the diet of co-occurring intertidal molluscs species within a community dominated by the oyster Crassostrea gigas and its epibiont, the common Atlantic slipper limpet Crepidula Fornicata. The results showed that the d13C versus d15N values of C. gigas differed from those of the deposit feeders considered but also from the other suspension-feeding molluscs (i.e. Mytilus edulis, Cerastoderma edule and C. Fornicata), being more depleted in 13C and in 15N. The results suggest more similarities in the assimilated food sources of C. Fornicata, C. edule and M. edulis. In particular, the d13C and d15N differences between C. gigas and C. Fornicata suggest that these associated suspension feeders in many shellfish culture areas may not necessarily be competitors for food sources when food is not limited. [KEYWORDS: Benthic food web · d13C · d15N · Molluscs · Crassostrea gigas · Crepidula Fornicata · Oosterschelde]

Jan A. Pechenik - One of the best experts on this subject based on the ideXlab platform.

  • The marine gastropod Crepidula Fornicata remains resilient to ocean acidification across two life history stages
    2020
    Co-Authors: Christopher L Reyes, Jan A. Pechenik, Brooke E Benson, Morgan Levy, Xuqing Chen, Anthony Pires, Sarah W. Davies
    Abstract:

    Abstract Rising atmospheric CO2 reduces seawater pH causing ocean acidification (OA). Understanding how resilient marine organisms respond to OA may help predict how community dynamics will shift as CO2 continues rising. The common slipper shell snail Crepidula Fornicata is a resilient marine gastropod native to eastern North America, which has been a successful invader along the western European coastline and elsewhere. To examine its potential resilience to OA, we conducted two controlled laboratory experiments. First, we examined several phenotypes and genome-wide gene expression of C. Fornicata in response to pH treatments (7.5, 7.6, 8.0) throughout the larval stage and then tested how conditions experienced as larvae influenced juvenile stages (i.e. carryover effects). Second, we examined genome-wide gene expression patterns of C. Fornicata larvae in response to acute (4, 10, 24 and 48 hours) pH treatment (7.5, 8.0). Both C. Fornicata larvae and juveniles exhibited resilience to OA and gene expression responses highlight the role of transcriptome plasticity in OA resilience. Larvae did not exhibit reduced growth under OA until they were at least 4 days old. These phenotypic effects were preceded by broad transcriptomic changes, which likely serve as an acclimation mechanism for combating reduced pH conditions frequently experienced in littoral zones. Delayed metamorphosis was observed for larvae reared at reduced pH. Although juvenile size reflected larval rearing pH conditions, no carryover effects in juvenile growth rates were observed. Transcriptomic analyses suggest increased metabolism under OA, which may indicate compensation in reduced pH environments. Time course transcriptomic analyses suggest energetic burdens experienced under OA eventually dissipate, allowing C. Fornicata to reduce metabolic demands and acclimate to reduced pH. This study highlights the importance of assessing the effects of OA across life history stages and demonstrates how transcriptomic plasticity can allow highly resilient organisms, like C. Fornicata, acclimate to reduced pH environments.

  • Resilience of Atlantic Slippersnail Crepidula Fornicata Larvae in the Face of Severe Coastal Acidification
    Frontiers in Marine Science, 2018
    Co-Authors: Nicola G. Kriefall, Jan A. Pechenik, Anthony Pires, Sarah W. Davies
    Abstract:

    Globally, average oceanic pH is dropping, and it will continue to decline into the foreseeable future. This ocean acidification (OA) will exacerbate the natural fluctuations in pH that nearshore ecosystems currently experience daily, potentially pushing marine organisms to their physiological limits. Adults of Crepidula Fornicata (the Atlantic slippersnail) have proven remarkably resilient to many environmental changes, which is perhaps not surprising considering that they are common intertidally, have a geographically large native range, and have been extremely successful at invading coastal water in many other parts of the world. However, the larvae of C. Fornicata have been shown to be somewhat more vulnerable than adults to the effects of reduced pH. Research to date has focused on the physiological impacts of OA on C. Fornicata larvae; few studies have explored shifts in gene expression resulting from changes in pH. In the present study, we examined the response of young (4-day old) C. Fornicata larvae to two extreme OA treatments (pH 7.5 and 7.6) relative to pH 8.0, documenting both phenotypic and genome-wide gene expression responses. We found that rearing larvae at reduced pH had subtle influences on gene expression, predominantly involving downregulation of genes related to growth and metabolism, accompanied by significantly reduced shell growth rates only for larvae reared at pH 7.5. Additionally, 10-day old larvae that had been reared at the two lower pH levels were far less likely to metamorphose within six hours when exposed to inducer. However, all larvae eventually reached similarly high levels of metamorphosis 24 hours after settlement induction. Finally, there were no observed impacts of OA on larval mortality. Taken together, our results indicate that far future OA levels have observable, but not severe, impacts on C. Fornicata larvae, which is consistent with the resilience of this invasive snail across rapidly changing nearshore ecosystems. We propose that future work should delve further into the physiological and transcriptomic responses of all life history stages to gain a more comprehensive understanding of how OA impacts the littoral gastropod C. Fornicata.

  • Resilience of Atlantic Slippersnail Crepidula Fornicata Larvae in the Face of Severe Coastal Acidification
    2018
    Co-Authors: Nicola G. Kriefall, Jan A. Pechenik, Anthony Pires, Sarah W. Davies
    Abstract:

    Globally, average oceanic pH is dropping, and it will continue to decline into the foreseeable future. This ocean acidification (OA) will exacerbate the natural fluctuations in pH that nearshore ecosystems currently experience daily, potentially pushing marine organisms to their physiological limits. Adults of Crepidula Fornicata (the Atlantic slippersnail) have proven remarkably resilient to many environmental changes, which is perhaps not surprising considering that they are common intertidally, have a geographically large native range, and have been extremely successful at invading coastal water in many other parts of the world. However, the larvae of C. Fornicata have been shown to be somewhat more vulnerable than adults to the effects of reduced pH. Research to date has focused on the physiological impacts of OA on C. Fornicata larvae; few studies have explored shifts in gene expression resulting from changes in pH. In the present study, we examined the response of young (4-day old) C. Fornicata larvae to two extreme OA treatments (pH 7.5 and 7.6) relative to pH 8.0, documenting both phenotypic and genome-wide gene expression responses. We found that rearing larvae at reduced pH had subtle influences on gene expression, predominantly involving downregulation of genes related to growth and metabolism, accompanied by significantly reduced shell growth rates only for larvae reared at pH 7.5. Additionally, 10-day old larvae that had been reared at the two lower pH levels were far less likely to metamorphose within six hours when exposed to inducer. However, all larvae eventually reached similarly high levels of metamorphosis 24 hours after settlement induction. Finally, there were no observed impacts of OA on larval mortality. Taken together, our results indicate that far future OA levels have observable, but not severe, impacts on C. Fornicata larvae, which is consistent with the resilience of this invasive snail across rapidly changing nearshore ecosystems. We propose that future work should delve further into the physiological and transcriptomic responses of all life history stages to gain a more comprehensive understanding of how OA impacts the intertidal gastropod C. Fornicata.

  • Data_Sheet_2_Resilience of Atlantic Slippersnail Crepidula Fornicata Larvae in the Face of Severe Coastal Acidification.CSV
    2018
    Co-Authors: Nicola G. Kriefall, Jan A. Pechenik, Anthony Pires, Sarah W. Davies
    Abstract:

    Globally, average oceanic pH is dropping, and it will continue to decline into the foreseeable future. This ocean acidification (OA) will exacerbate the natural fluctuations in pH that nearshore ecosystems currently experience daily, potentially pushing marine organisms to their physiological limits. Adults of Crepidula Fornicata (the Atlantic slippersnail) have proven remarkably resilient to many environmental changes, which is perhaps not surprising considering that they are common intertidally, have a geographically large native range, and have been extremely successful at invading coastal waters in many other parts of the world. However, the larvae of C. Fornicata have been shown to be somewhat more vulnerable than adults to the effects of reduced pH. Research to date has focused on the physiological impacts of OA on C. Fornicata larvae; few studies have explored shifts in gene expression resulting from changes in pH. In the present study, we examined the response of young (4-day old) C. Fornicata larvae to two extreme OA treatments (pH 7.5 and 7.6) relative to pH 8.0, documenting both phenotypic and genome-wide gene expression responses. We found that rearing larvae at reduced pH had subtle influences on gene expression, predominantly involving downregulation of genes related to growth and metabolism, accompanied by significantly reduced shell growth rates only for larvae reared at pH 7.5. Additionally, 10-day old larvae that had been reared at the two lower pH levels were far less likely to metamorphose within 6 h when exposed to inducer. However, all larvae eventually reached similarly high levels of metamorphosis 24 h after settlement induction. Finally, there were no observed impacts of OA on larval mortality. Taken together, our results indicate that far future OA levels have observable, but not severe, impacts on C. Fornicata larvae, which is consistent with the resilience of this invasive snail across rapidly changing nearshore ecosystems. We propose that future work should delve further into the physiological and transcriptomic responses of all life history stages to gain a more comprehensive understanding of how OA impacts the littoral gastropod C. Fornicata.

  • Data_Sheet_11_Resilience of Atlantic Slippersnail Crepidula Fornicata Larvae in the Face of Severe Coastal Acidification.CSV
    2018
    Co-Authors: Nicola G. Kriefall, Jan A. Pechenik, Anthony Pires, Sarah W. Davies
    Abstract:

    Globally, average oceanic pH is dropping, and it will continue to decline into the foreseeable future. This ocean acidification (OA) will exacerbate the natural fluctuations in pH that nearshore ecosystems currently experience daily, potentially pushing marine organisms to their physiological limits. Adults of Crepidula Fornicata (the Atlantic slippersnail) have proven remarkably resilient to many environmental changes, which is perhaps not surprising considering that they are common intertidally, have a geographically large native range, and have been extremely successful at invading coastal waters in many other parts of the world. However, the larvae of C. Fornicata have been shown to be somewhat more vulnerable than adults to the effects of reduced pH. Research to date has focused on the physiological impacts of OA on C. Fornicata larvae; few studies have explored shifts in gene expression resulting from changes in pH. In the present study, we examined the response of young (4-day old) C. Fornicata larvae to two extreme OA treatments (pH 7.5 and 7.6) relative to pH 8.0, documenting both phenotypic and genome-wide gene expression responses. We found that rearing larvae at reduced pH had subtle influences on gene expression, predominantly involving downregulation of genes related to growth and metabolism, accompanied by significantly reduced shell growth rates only for larvae reared at pH 7.5. Additionally, 10-day old larvae that had been reared at the two lower pH levels were far less likely to metamorphose within 6 h when exposed to inducer. However, all larvae eventually reached similarly high levels of metamorphosis 24 h after settlement induction. Finally, there were no observed impacts of OA on larval mortality. Taken together, our results indicate that far future OA levels have observable, but not severe, impacts on C. Fornicata larvae, which is consistent with the resilience of this invasive snail across rapidly changing nearshore ecosystems. We propose that future work should delve further into the physiological and transcriptomic responses of all life history stages to gain a more comprehensive understanding of how OA impacts the littoral gastropod C. Fornicata.