@article {Lema2019731, title = {Inter- and Intra-Specific Transcriptional and Phenotypic Responses of Pseudo-nitzschia under Different Nutrient Conditions}, journal = {Genome Biology and Evolution}, volume = {11}, number = {3}, year = {2019}, note = {cited By 1}, pages = {731-747}, publisher = {Oxford University Press}, abstract = {Untangling thefunctionalbasis of divergencebetweenclosely relatedspecies is a steptowardunderstanding speciesdynamicswithin communities at both the evolutionary and ecological scales. We investigated cellular (i.e., growth, domoic acid production, and nutrient consumption) and molecular (transcriptomic analyses) responses to varying nutrient concentrations across several strains belonging to three species of the toxic diatomgenus Pseudo-nitzschia. Threemain resultswere obtained. First, strains fromthe same species displayed similar transcriptomic, but not necessarily cellular, responses to the experimental conditions. It showed the importance of considering intraspecific diversity to investigate functional divergence between species. Second, a major exception to the first findingwas a strain recently isolated fromthe natural environment and displaying contrasting gene expression patterns related to cell motility and domoic acid production. This result illustrated the profound modifications thatmay occurwhen transferring a cell fromthe natural to the in vitro environment and asks for future studies to better understand the influence of culture duration and life cycleon expression patterns. Third, transcriptomic responsesweremore similarbetween the two speciesdisplaying similar ecology in situ, irrespective of the genetic distance. This was especially true formolecular responses related to TCA cycle, photosynthesis, and nitrogen metabolism. However, transcripts related to phosphate uptake were variable between species. It highlighted the importance of considering both overall genetic distance and ecological divergence to explain functional divergence between species. {\textcopyright} The Author(s) 2019. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.}, keywords = {analogs and derivatives, Biological Evolution, comparative study, Diatom, Diatoms, Domoic acid, evolution, kainic acid, Metabolism, Multigene Family, Nutrients, Phenotype, Physiology}, issn = {17596653}, doi = {10.1093/gbe/evz030}, url = {https://academic.oup.com/gbe/article/11/3/731/5332980}, author = {Lema, Kimberley A. and Metegnier, G. and Qu{\'e}r{\'e}, J. and Latimier, Marie and Agn{\`e}s Youenou and Lambert, Christophe and Juliette Fauchot and Le Gac, Mickael and Costantini, M.} } @article {6668, title = {Modelling the functioning of a coupled microphytobenthic-EPS-bacterial system in intertidal mudflats}, journal = {Marine Environmental Research}, volume = {150}, year = {2019}, abstract = {A mechanistic and biogeochemical model was developed to analyze the interactions between microphytobenthos (MPB), bacteria and nutrients in a tidal system. Behavioral vertical migration was hypothesized as being controlled by exogenous factors (tide and light) but also by endogenous factors (carbon and nitrogen requirements). The secretion of Extracellular Polymeric Substances (EPS) during photosynthesis (overflow metabolism) and migration of diatoms was also formulated. Similarities in MPB dynamics between observations and simulations support the assumption that carbon and nitrogen ratios are additional key processes behind the vertical migration of diatoms in the sediment. The model satisfactorily reproduced the three growth phases of the MPB development observed in a mesocosm (the lag phase, the logarithmic growth, and the plateau). Besides, nutrient availability, which could be induced by faunal bioturbation, significantly determined the extent of MPB biomass and development. The plateau phase observed in the last days of simulations appeared to be attributed to a nutrient depletion in the system, emphasizing the importance of nutrient availability. The model, although improvable especially on the formulation of the EPS excretion and bacteria development, already updated understanding of several aspects of benthic-system functioning during experimental conditions. {\textcopyright} 2019 Elsevier Ltd}, keywords = {Bacillariophyta, bacteria, Bacteria (microorganisms), bacterial growth, bacterium, Biogeochemical modeling, biogeochemistry, Biomass, Carbon, Carbon and nitrogen, Carbon and nitrogen ratios, Diatom, diel vertical migration, exopolymer, Experimental conditions, Extracellular polymeric substances, intertidal environment, intertidal zone, light, mesocosm, microbial community, Microphytobenthos, Migration, modeling, mudflat, Nitrogen, nonhuman, Nutrient availability, Nutrients, nutritional requirement, organic carbon, organismal interaction, Photosynthesis, Phytobenthos, Phytoplankton, polymer, Review, simulation, tide, vertical migration}, issn = {01411136}, doi = {10.1016/j.marenvres.2019.104754}, url = {https://www.sciencedirect.com/science/article/abs/pii/S0141113619300704}, author = {Rakotomalala, C and Katell Guizien and Karine Granger{\'e} and S{\'e}bastien Lefebvre and Christine Dupuy and Francis Orvain} } @article {vanderHeijden201950, title = {Trophic importance of microphytobenthos and bacteria to meiofauna in soft-bottom intertidal habitats: A combined trophic marker approach}, journal = {Marine Environmental Research}, volume = {149}, year = {2019}, note = {cited By 2}, pages = {50-66}, publisher = {Elsevier Ltd}, abstract = {Meiofauna can play an important role in the carbon fluxes of soft-bottom coastal habitats. Investigation of their feeding behavior and trophic position remains challenging due to their small size. In this study, we determine and compare the food sources used by nematodes and benthic copepods by using stable isotope compositions, fatty acid profiles and compound specific isotope analyses of fatty acids in the mudflats, seagrass beds and a sandflat of the Marennes-Ol{\'e}ron Bay, France, and the Sylt-R{\o}m{\o} Bight, Germany. Suspended particulate organic matter was much more 13C-depleted than other food sources and meiofauna, highlighting its poor role in the different studied habitats. The very low proportions of vascular plant fatty acid markers in meiofauna demonstrated that these consumers did not rely on this food source, either fresh or detrital, even in seagrass beds. The combined use of stable isotopes and fatty acids emphasized microphytobenthos and benthic bacteria as the major food sources of nematodes and benthic copepods. Compound specific analyses of a bacteria marker confirmed that bacteria mostly used microphytobenthos as a substrate. {\textcopyright} 2019 Elsevier Ltd}, keywords = {Article, Bacillariophyta, bacteria, bacterium, Benthic copepods, Benthic diatoms, Biological materials, biomarker, Biomass, carbon 13, coastal zone, controlled study, Copepoda, delta carbon 13, delta nitrogen 15, Diatom, Ecosystems, fatty acids, Feeding Behavior, food supply, France, Free livings, Freeze Drying, Frisian Islands, Germany, high performance liquid chromatography, intertidal environment, isotope analysis, Isotopes, lipid composition, Marennes-Oleron Bay, Meiofauna, microbial activity, Microphytobenthos, mudflat, Mudflats, Nematoda, nitrogen 15, nonhuman, North Frisian Islands, Nouvelle-Aquitaine, Organic matter, Phytobenthos, Plants (botany), Sandflats, seagrass, Seagrass beds, Sediment, soft-bottom environment, species habitat, substrate, suspended particulate organic matter, Sylt-Romo Bight, trophic environment, Trophic markers, Trophic structure, unclassified drug}, issn = {01411136}, doi = {10.1016/j.marenvres.2019.05.014}, url = {https://www.sciencedirect.com/science/article/abs/pii/S0141113618304744}, author = {van der Heijden, L.H. and Graeve, M. and R. Asmus and Rzeznik-Orignac, J. and Nathalie Niquil and Bernier, Q. and Guillou, G. and H Asmus and Lebreton, B.} } @article {Thorel2017192, title = {Nutrient ratios influence variability in Pseudo-nitzschia species diversity and particulate domoic acid production in the Bay of Seine (France)}, journal = {Harmful Algae}, volume = {68}, year = {2017}, note = {cited By 15}, pages = {192-205}, publisher = {Elsevier B.V.}, abstract = {The population dynamics of different Pseudo-nitzschia species, along with particulate domoic acid (pDA) concentrations, were studied from May 2012 to December 2013 in the Bay of Seine (English Channel, Normandy). While Pseudo-nitzschia spp. blooms occurred during the two years of study, Pseudo-nitzschia species diversity and particulate domoic acid concentrations varied greatly. In 2012, three different species were identified during the spring bloom (P. australis, P. pungens and P. fraudulenta) with high pDA concentrations (\~{}1400 ng l-1) resulting in shellfish harvesting closures. In contrast, the 2013 spring was characterised by a P. delicatissima bloom without any toxic event. Above all, the results show that high pDA concentrations coincided with the presence of P. australis and with potential silicate limitation (Si:N \< 1), while nitrate concentrations were still replete. The contrasting environmental conditions between 2012 and 2013 highlight different environmental controls that might favour the development of either P. delicatissima or P. australis. This study points to the key role of Pseudo-nitzschia diversity and cellular toxicity in the control of particulate domoic acid variations and highlights the fact that diversity and toxicity are influenced by nutrients, especially nutrient ratios. {\textcopyright} 2017 Elsevier B.V.}, keywords = {analogs and derivatives, analysis, Bay, Bays, Biodiversity, chemistry, Diatom, Diatoms, Domoic acid, France, Geography, kainic acid, Nitrates, nitric acid derivative, particulate matter, phosphate, Phosphates, Physiology, Phytoplankton, Principal Component Analysis, season, Seasons, species difference, Species Specificity, time factor, Time Factors}, issn = {15689883}, doi = {10.1016/j.hal.2017.07.005}, url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85028543709\&doi=10.1016\%2fj.hal.2017.07.005\&partnerID=40\&md5=def23b37b0d16a1ae7ab65a7ef2b940b}, author = {Thorel, Maxine and Pascal Claquin and Mathilde Schapira and Romain Le Gendre and Riou, Philippe and Didier Goux and Bertrand Le Roy and Raimbault, V and Deton-Cabanillas, A.-F. and Bazin, Pauline and Kientz-Bouchart, Val{\'e}rie and Juliette Fauchot} }