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| Fouilland, Eric; Le Floc'H, Emilie; Brennan, Debra; Bell, Elanor M.; Lordsmith, Sian L.; Mcneill, Sharon; Mitchell, Elaine; Brand, Tim D.; Garcia-martin, E. Elena; Leakey, Raymond J. G.. |
| Recent observations in polar marine waters have shown that a large fraction of primary production may be lost to respiration by planktonic bacteria due to very low bacterial growth efficiencies in cold waters. Here we report that sea temperature may be a key factor influencing the interaction between bacteria and primary production in North Atlantic and Arctic waters, suggesting that low primary production rates could not sustain bacterial carbon demand in the coldest Arctic waters. The use of freshly produced phytoplankton exudate by bacteria in early- and mid-summer was assessed, together with the bacterial uptake of dissolved inorganic nitrogen (DIN = nitrate and ammonium), in surface waters along a latitudinal gradient from the North Sea to the Arctic... |
| Tipo: Text |
Palavras-chave: Carbon coupling; Arctic waters; Phytoplankton and bacteria interactions; Nitrogen fluxes. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00453/56417/58087.pdf |
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| Gales, Amandine; Triplet, Sebastien; Geoffroy, Thibault; Roques, Cécile; Carre, Claire; Le Floc'H, Emilie; Lanfranchi, Mélissa; Simier, Monique; Roque D'Orbcastel, Emmanuelle; Przybyla, Cyrille; Fouilland, Eric. |
| Recently, CO2 recycling for the production of valuable microalgae has acquired substantial interest. Most studies investigating CO2 conversion efficiency in algal cultures were based on single species, although a stabilising effect of algal diversity on biomass production was recently highlighted. However, addition of CO2 into polyalgal cultures requires a careful control of pH; performance of CO2 conversion, growth and carbon biomass production are affected by pH differently, depending on the species of microalgae. This study investigates the efficiency of CO2 conversion by natural marine algal assemblage cultivated in open, land-based raceways (4.5 m3, 10 m2), working as high rate algal ponds (HRAP). Ponds were enriched with nitrogen and phosphate, pure... |
| Tipo: Text |
Palavras-chave: Carbon yield; Microalgal diversity; PH; Predators. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00612/72403/71392.pdf |
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| Krichen, Emna; Rapaport, Alain; Le Floc'H, Emilie; Fouilland, Eric. |
| Positive interactions such as facilitation play an important role during the biological colonization and species succession in harsh or changing environments. However, the direct evidence of such ecological interaction in microbial communities remains rare. Using common freshwater microalgae isolated from a High Rate Algal Pond HRAP treating wastewaters, we investigated with both experimental and modeling approaches the direct facilitation between two algal strains during the colonization phase. Our results demonstrate that the first colonization by microalgae under a severe chemical condition arose from the rapid growth of pioneer species such as Chlorella sorokiniana, which facilitated the subsequent colonization of low growth specialists such as... |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00592/70434/68528.pdf |
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| Sarazin, Gérard; Jezequel, Didier; Leboulanger, Christophe; Fouilland, Eric; Le Floc'H, Emilie; Bouvy, Marc; Gerard, Emmanuelle; Agogué, Hélène; Bernard, Cédric; Hugoni, Mylène; Grossi, Vincent; Trousselier, Marc; Ader, Magali. |
| Dziani Dzaha is a maar the age of which is close to 4000 years. While its water is thought to have originated from seawater it is now considered as an extreme environment due to its hypersaline and alkaline characteristics. Those extreme features have led to the simplification of the trophic network. Cyanobacteria account for up to 95% of the photosynthetic biomass. The main biogeochemical processes, i.e. photosynthesis, bacterial sulfate reduction and methanogenesis could explain the current water composition. As far as we know, this ecosystem could be unique on Earth, extending the nature and chemical limits of aquatic inland ecosystems |
| Tipo: Text |
Palavras-chave: Thalassohaline lake; Endorheic ecosystem; Cyanobacteria; Methane emission; Biogeochemistry; Mayotte. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00667/77948/80128.pdf |
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| Galès, Amandine; Bonnafous, Anaïs; Carré, Claire; Jauzein, Vincent; Lanouguère, Elodie; Le Floc'H, Emilie; Pinoit, Joanna; Poullain, Clothilde; Roques, Cécile; Sialve, Bruno; Simier, Monique; Steyer, Jean-philippe; Fouilland, Eric. |
| Several studies focused on wastewater treatment in High Rate Algal Ponds (HRAP) suggest that highly variable climatic conditions cause large variations of microalgal biomass productivity. In the present study, we show that similar carbon, nitrogen and phosphorus removal efficiencies were reached in different HRAPs treating urban wastewaters located in two different temperate (Mediterranean and oceanic) climates. Furthermore, similar ecological successions were observed in these HRAPs. During the start-up phase, the consumption of organic matter by detritivores, already present in the wastewater, appears to be necessary for the microalgae to grow within two weeks in spring. The growth of the rapid-growing species, Chlorella sp., followed by the... |
| Tipo: Text |
Palavras-chave: Microalgae; Predators; Bacteria; Urban effluents; Ammonia and phosphate removal. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00490/60210/63713.pdf |
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| Leboulanger, Christophe; Agogue, Helene; Bernard, Cecile; Bouvy, Marc; Carre, Claire; Cellamare, Maria; Duval, Charlotte; Fouilland, Eric; Got, Patrice; Intertaglia, Laurent; Lavergne, Celine; Le Floc'H, Emilie; Roques, Cecile; Sarazin, Gerard. |
| This study describes, for the first time, the water chemistry and microbial diversity in Dziani Dzaha, a tropical crater lake located on Mayotte Island (Comoros archipelago, Western Indian Ocean). The lake water had a high level of dissolved matter and high alkalinity (10.614.5 g L-1 eq. CO32-, i.e. 160220 mM compare to around 22.5 in seawater), with salinity up to 52 psu, 1.5 higher than seawater. Hierarchical clustering discriminated Dziani Dzaha water from other alkaline, saline lakes, highlighting its thalassohaline nature. The phytoplankton biomass was very high, with a total chlorophyll a concentration of 524 to 875 mu g chl a L-1 depending on the survey, homogeneously distributed from surface to bottom (4 m). Throughout the whole water column the... |
| Tipo: Text |
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| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00625/73731/74808.pdf |
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| Mostajir, Behzad; Roques, Cecile; Bouvier, Corinne; Bouvier, Thierry; Fouilland, Eric; Got, Patrice; Le Floc'H, Emilie; Nouguier, Jean; Mas, Sebastien; Sempere, Richard; Sime-ngando, Telesphore; Troussellier, Marc; Vidussi, Francesca. |
| The impact of fish and oysters on components of the pelagic microbial food web (MFW) was studied in a 10 d mesocosm experiment using Mediterranean coastal waters. Two mesocosms contained natural water only ('Controls'), 2 contained natural water with Crassostrea gigas ('Oyster'), and 2 contained natural water with Atherina spp. ('Fish'). Abundances and biomasses of microorganisms (viruses, bacteria, phytoplankton, heterotrophic flagellates, and ciliates) were measured to estimate their contribution to the total microbial carbon biomass. Two MFW indices, the microbial autotroph: heterotroph C biomass ratio (A:H) structural index and the gross primary production: respiration ratio (GPP:R) functional index, were defined. In the Fish mesocosms, selective... |
| Tipo: Text |
Palavras-chave: Microbial food web; Virioplankton; Bacterioplankton; Phytoplankton; Protozooplankton; Crassostrea; Atherina; Autotrophy; Heterotrophy. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00284/39489/73675.pdf |
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| Alves-de-souza, Catharina; Pecqueur, David; Le Floc'H, Emilie; Mas, Sebastien; Roques, Cecile; Mostajir, Behzad; Vidussi, Franscesca; Velo-suarez, Lourdes; Sourisseau, Marc; Fouilland, Eric; Guillou, Laure. |
| Dinoflagellate blooms are frequently observed under temporary eutrophication of coastal waters after heavy rains. Growth of these opportunistic microalgae is believed to be promoted by sudden input of nutrients and the absence or inefficiency of their natural enemies, such as grazers and parasites. Here, numerical simulations indicate that increasing nutrient availability not only promotes the formation of dinoflagellate blooms but can also stimulate their control by protozoan parasites. Moreover, high abundance of phytoplankton other than dinoflagellate hosts might have a significant dilution effect on the control of dinoflagellate blooms by parasites, either by resource competition with dinoflagellates (thus limiting the number of hosts available for... |
| Tipo: Text |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00274/38478/36938.pdf |
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