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| Bird, Clare; Lekieffre, Charlotte; Jauffrais, Thierry; Meibom, Anders; Geslin, Emmanuelle; Filipsson, Helena L.; Maire, Olivier; Russell, Ann D.; Fehrenbacher, Jennifer S.. |
| Nitrogen availability often limits biological productivity in marine systems, where inorganic nitrogen, such as ammonium is assimilated into the food web by bacteria and photoautotrophic eukaryotes. Recently, ammonium assimilation was observed in kleptoplast-containing protists of the phylum foraminifera, possibly via the glutamine synthetase/glutamate synthase (GS/GOGAT) assimilation pathway imported with the kleptoplasts. However, it is not known if the ubiquitous and diverse heterotrophic protists have an innate ability for ammonium assimilation. Using stable isotope incubations (15N-ammonium and 13C-bicarbonate) and combining transmission electron microscopy (TEM) with quantitative nanoscale secondary ion mass spectrometry (NanoSIMS) imaging, we... |
| Tipo: Text |
Palavras-chave: Nitrogen cycle; Heterotrophic protists; Foraminifera; Ammonium assimilation; Heterotrophy; Marine. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00662/77421/79087.pdf |
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| Bernard, Guillaume; Duchene, Jean-claude; Romero-ramirez, Alicia; Lecroart, Pascal; Maire, Olivier; Ciutat, Aurelie; Deflandre, Bruno; Gremare, Antoine. |
| The effects of temperature and food addition on particle mixing in the deposit-feeding bivalve Abra alba were assessed using an experimental approach allowing for the tracking of individual fluorescent particle (luminophore) displacements. This allowed for the computations of vertical profiles of a set of parameters describing particle mixing. The frequency of luminophore displacements (jumps) was assessed through the measurement of both waiting times (i.e., the time lapses between two consecutive jumps of the same luminophore) and normalized numbers of jumps (i.e., the numbers of jumps detected in a given area divided by the number of luminophores in this area). Jump characteristics included the direction, duration and length of each jump. Particle... |
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| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00375/48615/49432.pdf |
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| Jauffrais, Thierry; Lekieffre, Charlotte; Schweizer, Magali; Geslin, Emmanuelle; Metzger, Edouard; Bernhard, Joan M.; Jesus, Bruno; Filipsson, Helena L.; Maire, Olivier; Meibom, Anders. |
| The assimilation of inorganic compounds in foraminiferal metabolism compared to predation or organic matter assimilation is unknown. Here we investigate possible inorganic‐compound assimilation in Nonionellina labradorica, a common kleptoplastidic benthic foraminifer from Arctic and North Atlantic sublittoral regions. The objectives were to identify the source of the foraminiferal kleptoplasts, assess their photosynthetic functionality in light and darkness, and investigate inorganic nitrogen and sulfate assimilation. We used DNA barcoding of a ~830 bp fragment from the SSU rDNA to identify the kleptoplasts, and correlated transmission electron microscopy and nanometer‐scale secondary ion mass spectrometry (TEM‐NanoSIMS) isotopic imaging to study... |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00460/57188/59151.pdf |
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