Dominique Davoult
Sorbonne Université, Station Biologique de Roscoff, Faculty Member
- Sorbonnes Universités, UPMC (P6), Station Biologique de Roscoff, Faculty Memberadd
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New reports of benthic species from the french coasts of the eastern English Channel and the North Sea. Twenty six benthic species from several phyla have been found for the first time in the French part of the eastern English Channel and... more
New reports of benthic species from the french coasts of the eastern English Channel and the North Sea. Twenty six benthic species from several phyla have been found for the first time in the French part of the eastern English Channel and of the North sea : one Nematoda (Synonchus brevisetosus), one Nemertean (Tetrastemma helvolum), twelve polychaeta Annelida (Spio decoratus, Capitella giardi, Mediomastus fragilis, Phyllodoce longipes, Hesionura elongata, Glycera celtica, Glycera oxycephala, Nephtys assimilis, Myriochele oculata, Chone filicaudata, Fabricia sabella and Protodriloides chaetifer), one lamellibranchiata Mollusca (Ensis directus), five Bryozoans (Eurystrotos compacta, Scruparia ambigua, Amphiblestrum flemingii, Hippopodinella lata and Plesiothoa gigerium), one Phoronida (Phoronis muelleri), one Entoprocta (Pedicellina hispida) and four malacostracean Crustacea (Harpinia antennaria, Idotea metallica, Tanaopsis graciloides and Gastrosaccus sanctus). Their biotope and geog...
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Intertidal communities dominated by canopy-forming brown algae (Phaeophyceae) usually prove to be highly productive systems, based on short-term measurements. However, long-term metabolism (primary production and respiration) is sensitive... more
Intertidal communities dominated by canopy-forming brown algae (Phaeophyceae) usually prove to be highly productive systems, based on short-term measurements. However, long-term metabolism (primary production and respiration) is sensitive to several factors acting on different time scales (e.g. tidal cycle, seasonality), making its assessment challenging. Here, we used mathematical modelling to investigate the metabolism of aFucus serratus-dominated community on daily and annual time scales. This widespread community, which is usually characteristic of the low mid-intertidal level of temperate rocky shores, is submerged for approximately 83% of the time at our study site (Brittany, France). The model incorporated a large spectrum of physiological (e.g. estimates of primary production versus irradiance parameters) and environmental (e.g. temperature, incident irradiance, depth of the water column) parameters measuredin situ. The model simulation predicted that net community primary p...
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Long-term variations (1979–1990) of three benthic communities (Eastern Channel, France) were analysed by means of factor correspondence analysis (FCA), a multivariate method of ordination in reduced space, and rank-frequency diagrams... more
Long-term variations (1979–1990) of three benthic communities (Eastern Channel, France) were analysed by means of factor correspondence analysis (FCA), a multivariate method of ordination in reduced space, and rank-frequency diagrams (RFD). FCA distinguished periods of relative homogeneity and periods of strong variations in the structure of the communities. Two communities, the pebbles community and a rich and diverse mussel (Mytilus edulis) bed, showed great variations in the abundance of the main species (Ophiothrix fragilis in the first one, andM. edulis in the second one) which generated the enrichment of the community by their suspension-feeding behaviour. Beyond the multi-annual cycle induced by these variations, both communities seemed to be quite stable as no continuing trends could be seen. The third community, established on heterogeneous sand, also showed a multi-annual cycle linked to granulometric variations of the sediment. As passive supplies of detritus were not important and suspension feeders could hardly live in these conditions, the community stayed poor and was dominated by carnivores and deposit-feeders.
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As a result of urbanization, coastal environments are being disturbed by various anthropogenic pressures. These are concentrated in harbor areas where the addition of artificial structures and the presence of pollutants seems to favor the... more
As a result of urbanization, coastal environments are being disturbed by various anthropogenic pressures. These are concentrated in harbor areas where the addition of artificial structures and the presence of pollutants seems to favor the settlement of non-indigenous species. Most studies on these organisms are often carried out in a single time window without integrating temporal variability. Here, we analyzed multi-year photographic data of marina communities taken from 3 experiments conducted between 2016 and 2019 in the same marina. These photographs were of recruitment plates placed at the inner, middle and entrance locations of the marina, permitting us to discern the community differences and the distribution of non-indigenous taxa between these 3 locations. Over the entire study period, the communities that grew at the entrance and the inner locations of the marina were always different. Non-indigenous taxa also appeared to be more prevalent in the inner location of the mari...
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Made up of calcareous coralline algae, maerl beds play a major role as ecosystem engineers in coastal areas throughout the world. They undergo strong anthropogenic pressures, which may threaten their survival. The aim of this study was to... more
Made up of calcareous coralline algae, maerl beds play a major role as ecosystem engineers in coastal areas throughout the world. They undergo strong anthropogenic pressures, which may threaten their survival. The aim of this study was to gain insight into the future of maerl beds in the context of global and local changes. We examined the effects of rising temperatures (+3°C) and ocean acidification (−0.3 pH units) according to temperature and pH projections (i.e., the RCP 8.5 scenario), and nutrient (N and P) availability on three temperate maerl species (Lithothamnion corallioides, Phymatolithon calcareum, and Lithophyllum incrustans) in the laboratory in winter and summer conditions. Physiological rates of primary production, respiration, and calcification were measured on all three species in each treatment and season. The physiological response of maerl to global climate change was species‐specific and influenced by seawater nutrient concentrations. Future temperature–pH scena...
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ABSTRACT The relative contribution of kelps and other food sources to the diet of consumers in shallow coastal communities has been hotly debated in recent years. It has been suggested that considering proxies instead of phytoplankton... more
ABSTRACT The relative contribution of kelps and other food sources to the diet of consumers in shallow coastal communities has been hotly debated in recent years. It has been suggested that considering proxies instead of phytoplankton isotopic signatures can lead to an overestimation of kelp contribution through isotopic mixing models. We analysed spatial patterns in carbon isotopic ratios of the dominant primary sources and consumers at two subtidal sites in Brittany (France) prior to the anticipated 2011 phytoplankton bloom to determine which of kelp and phytoplankton is the dominant food source in Laminaria hyperborea forests. We found simultaneous spatial variations for consumers, kelps and deposited particulate organic matter, suggesting that kelp-derived organic matter is a key component of associated food webs for at least part of the year.
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Research Interests: Botany, Zoology, Oceanography, Photosynthesis, Biology, and 5 moreEcology, Xanthophyll Cycle, Kelp, Photoinhibition, and laminaria
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The ability of Laminaria digitata (Hudson) J.V. Lamouroux to cope with rapid and drastic changes in light was studied in the field by measuring photosystem II fluorescence, net oxygen roduction and pigment content. Experiments were... more
The ability of Laminaria digitata (Hudson) J.V. Lamouroux to cope with rapid and drastic changes in light was studied in the field by measuring photosystem II fluorescence, net oxygen roduction and pigment content. Experiments were conducted during two spring tides of late spring in Northern Brittany where low spring tides occur around noon. Daily patterns of the photosynthetic performance of Laminaria digitata were observed in relation to changes in incident under- water light. Photoinhibitory light exposure induced a sharp decrease of the optimal quantum yield (Fv/Fm), a decline of the net oxygen production in the first of the two spring tides investigated and a concomitant increase in the de-epoxidation ratio of the Violaxanthin pool. Photoinhibition persisted at a lower extent at the end of the day and complete recovery was achieved during the night. The implications of the photoinhibition of photosynthesis of Laminaria digitata are discussed in relation to the natural ambient conditions experienced in the field.
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Over the last decade, the commercially harvested quantities of the kelp Laminaria digitata have decreased along the coast of Brittany, falling from an annual production of around 60,000 t to the current production of 50,000 t... more
Over the last decade, the commercially harvested quantities of the kelp Laminaria digitata have decreased along the coast of Brittany, falling from an annual production of around 60,000 t to the current production of 50,000 t Environmental parameters and the intensity of harvesting are the main potential sources of this decline. To analyse the impact of the environment, several environmental factors such as temperature, light intensity and storm intensity were included in multivariate analyses to explore their potential effects on standing stock variables (density and biomass of L. digitata populations in north Finistere). Results show relatively limited temporal fluctuations in biomass and density, although density has generally increased since 2000. Biomass appeared to follow a periodic cycle of 12 years, but could not be linked to any environmental factor. Temperature seemed to have the largest effect (negative when it increases), although this effect was masked during the last years of the study period. Analyses on harvest data revealed that the lower landings of L. digitata were not correlated to a decrease in the available algal stock but to insufficient harvesting effort. This may be due to a decrease in the number of days spent harvesting kelp and in the number of kelp-harvesting vessels. While the production per vessel has increased since 2000, this increase was insufficient to increase or even maintain total production.
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... occur regularly on these low levels. However, since 1997 a reduction of L. digitata has been observed on the Brittany coast and for 56 years in the eastern English Channel. Like terrestrial system, Laminariales could be subject ...
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The two brittle-stars Acrocnida brachiata (Montagu 1804) and A. spatulispina (Stöhr and Muths in J Mar Biol Assoc, 2009) exhibit strong spatial segregation along the coast of Brittany (France), the first being subtidally distributed... more
The two brittle-stars Acrocnida brachiata (Montagu 1804) and A. spatulispina (Stöhr and Muths in J Mar Biol Assoc, 2009) exhibit strong spatial segregation along the coast of Brittany (France), the first being subtidally distributed relative to the other intertidal species. Despite a very high degree of mitochondrial DNA divergence, previous preliminary results hinted at the potential for hybridization to occur. Therefore, we specifically aim to determine local levels of hybridization between these two species and to investigate the relative roles of pre- and post- zygotic isolation processes acting to decrease local hybridization patterns. Mitochondrial DNA, allozymes and the Internal Transcribed Spacer 2 region of the ribosomal DNA were all used on 529 brittle-stars sampled locally in June and September 2005, among six stations in Douarnenez Bay, a site situated at the tip of Brittany. Only 2.6% of all samples analyzed were identified as potential hybrids. However, these were twice more frequent in June, just after the reproductive period, than in September after selective mortality acted to reduce the proportions of hybrids. In addition to the abrupt bathymetric segregation between the two species, spawning asynchrony also clearly restricts hybridization to low levels, which shows the importance of pre-zygotic mechanisms in maintaining reproductive isolation. Moreover, both limited hybridization events and adult mortalities following reproduction tend to generate local genetic differentiation at the intra-species level. On the contrary, the genetic structure is homogenized by migration of juveniles or adults and hybrids mortalities over the summer period.
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Research Interests: Engineering, Chemistry, Diversity, Carbon Dioxide, Biomass, and 15 moreBiology, Ecology, Biodiversity, Medicine, Canopy, Atlantic Ocean, Field Experiment, Abundance, Ecosystem, Intertidal Zone, Analysis of Variance, Interaction effect, Mechanical Processes, Community Respiration, and community property
ABSTRACT Two populations of Laminaria digitata (Hudson) Lamouroux (Ann Mus Hist Nat Paris 20:21–47, 1813) were examined for their seasonal photosynthetic acclimation to clear and turbid-light environments along the French coast of the... more
ABSTRACT Two populations of Laminaria digitata (Hudson) Lamouroux (Ann Mus Hist Nat Paris 20:21–47, 1813) were examined for their seasonal photosynthetic acclimation to clear and turbid-light environments along the French coast of the English Channel. Photosynthesis–irradiance curves, pigment concentrations and the daily in situ integrated oxygen production rates were measured in both populations. Despite the great differences in light attenuation between the sites, the two populations achieved similar oxygen production rates in the field, in relation to high maximal photosynthetic rates, total pigment concentrations and antenna (fucoxanthin + chlorophyll c)/chl a pigment ratios in sporophytes from the turbid environment. Environmental conditions (i.e. light, temperature and nitrogen availability) changed throughout the year in both sites. While the seasonal acclimation trends were evident in the clear-light environment, the strategy in the turbid-light environment differed, tending to maximize light capture throughout the year. This study highlights the diversity of the response of a single species to contrasted light environments.
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ABSTRACT Demographic functioning of the brittle-star Ophiothrix fragilis (Abildgaard) has been surveyed in parallel at three subtidal localities of the English Channel, from South-West to North-East. Population dynamics survey of dense... more
ABSTRACT Demographic functioning of the brittle-star Ophiothrix fragilis (Abildgaard) has been surveyed in parallel at three subtidal localities of the English Channel, from South-West to North-East. Population dynamics survey of dense beds of O. fragilis shows important demographic discrepancies between localities across the English Channel with a great heterogeneity in recruitment, both in space and time. At least, two major types of populations seem to exist, those having an important annual recruitment with post-settlement density regulation and, those with slower population replenishment due to a limiting amount of settlers. Whatever the dynamics is, stability of populations is ensured over time
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Research Interests: Geography, Earth Sciences, Oceanography, Microphytobenthos, Biological Sciences, and 12 moreEnvironmental Sciences, Primary Production, Tidal Current Measurement, Intertidal Zone, Saint, In Situ Measurements, PAM fluorometry, Benthic Boundary Layer, Temporal Variability, Bay, Community Respiration, and Electron Transport Rate
Biometrics refers to methods for uniquely recognising humans based upon one or more intrinsic physical or behavioural traits. In information technology in particular, biometrics is used as a form of identity access management and access... more
Biometrics refers to methods for uniquely recognising humans based upon one or more intrinsic physical or behavioural traits. In information technology in particular, biometrics is used as a form of identity access management and access control. It is also used to identify individuals in groups that are under surveillance. Biometric characteristics can be divided in two main classes: physiological and behavioural. Physiological examples include fingerprints, face recognition, DNA, hand and palm geometry, iris recognition, which has largely replaced retina, and odour/scent. Behavioural examples include typing rhythm, gait, and voice. This book gathers the latest research in the field of biometrics and focuses on topics such as on-line signature verification, improving the performance of colour spaces in face recognition, block coding schemes designed for biometrical authentication, large scale palm print identification and distributional properties of count outcomes and limitations o...
Research Interests: Biometrics and Ecology
Cycling of organic carbon in the ocean has the potential to mitigate or exacerbate global climate change, but major questions remain about the environmental controls on organic carbon flux in the coastal zone. Here, we used a field... more
Cycling of organic carbon in the ocean has the potential to mitigate or exacerbate global climate change, but major questions remain about the environmental controls on organic carbon flux in the coastal zone. Here, we used a field experiment distributed across 28° of latitude, and the entire range of 2 dominant kelp species in the northern hemisphere, to measure decomposition rates of kelp detritus on the seafloor in relation to local environmental factors. Detritus decomposition in both species were strongly related to ocean temperature and initial carbon content, with higher rates of biomass loss at lower latitudes with warmer temperatures. Our experiment showed slow overall decomposition and turnover of kelp detritus and modeling of coastal residence times at our study sites revealed that a significant portion of this production can remain intact long enough to reach deep marine sinks. The results suggest that decomposition of these kelp species could accelerate with ocean warmi...