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| Graneli, Edna; Anderson, Donald M; Carlsson, Per; Maestrini, Serge Y. |
| The marine dinoflagellate genus Dinophysis includes species that are the causative agents of diarrhetic shellfish poisoning (DSP). Recent findings indicate that some Dinophysis species are mixotrophic, i.e. capable of both autotrophic and heterotrophic nutrition. We investigated inorganic (and organic) carbon uptake by several species of Dinophysis in the Light and dark using the 'single-cell C-14 method', and compared uptake rates with those of photosynthetic Ceratium species and heterotrophic dinoflagellates in the genus Protoperidinium. Experiments were conducted with water from the Gullmar Fjord and from the Koster Strait (Swedish west coast). Nutrient-enriched phytoplankton from surface water samples were concentrated (20 to 70 mu m) and incubated at... |
| Tipo: Text |
Palavras-chave: Dinophysis; Growth rate; Mixotrophy; Carbon uptake; Ceratium; Protoperidinium. |
| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00336/44679/45050.pdf |
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| Berland, Brigitte R; Maestrini, Serge Y; Grzebyk, Daniel. |
| Some aspects of the life-cycle have been investigated in Dinophysis cf, acuminata, the dominant species of the genus along the French Atlantic coast, as well as in D, acuta; a few observations have also been made on the Mediterranean species D. pavillardi. Dinophysis cells occur in 2 clearly distinguished sizes. Small cells typically had a theca thinner than large cells, and cingular and sulcal lists were less developed. Both small and large cells were seen dividing, producing 1 to 4 round intracellular bodies. Some of these round bodies in turn contained many small flagellated cells which escaped through a pore and swam rapidly. Their behaviour after release, and how they might give rise to vegetative cells, has not been observed thus far; we do not... |
| Tipo: Text |
Palavras-chave: Dinophysis sp.; Life cycle; Cyst. |
| Ano: 1995 |
URL: http://archimer.ifremer.fr/doc/00258/36957/35626.pdf |
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| Berland, Brigitte R; Maestrini, Serge Y; Grzebyk, Daniel; Thomas, Pierre. |
| No species of Dinophysis has yet been cultured in the full sense. To determine the photosynthetic capability in D. cf. acuminata, the dominant morphotype of the genus along the French Atlantic coast, we took material from natural populations, in some trials by pipetting out single cells, and in others using plankton assemblages enriched in D. cf, acuminata by size fractionation and reverse sedimentation. Inorganic carbon uptake was measured at temperatures from 11 to 23 degrees C and at a light intensity of 400 mu mol photons m(-2) s(-1). Total uptake was proportional to the number of cells and increased linearly with incubation time, the uptake rate showing a distinct maximum at 18 degrees C, while at 23 degrees C being only half this maximum.... |
| Tipo: Text |
Palavras-chave: Dinophysis cf. acuminata; Nutrition; Ultrastructure. |
| Ano: 1995 |
URL: http://archimer.ifremer.fr/doc/00258/36958/35624.pdf |
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| Purvina, S; Béchemin, Christian; Balode, M; Verite, Celine; Arnaud, Christophe; Maestrini, Serge Y. |
| The use of riverine dissolved organic matter by the heterotrophic bacteria associated with a culture of the cyanobacterium Microcystis aeruginosa and release of simple nitrogen compounds were studied in an experimental series. Bacteria reduced the bulk of dissolved organic nitrogen (DON) by half, but when associated with M. aeruginosa, DON was excreted and its concentration rose by 13%. During the stationary growth phase bacteria released ammonium, doubling the concentration of ammonia as well as of nitrates. Bacteria associated with M. aeruginosa consumed riverine DON and joined the ammonification and nitrification process, supplying cyanobacteria with simple nitrogen compounds. |
| Tipo: Text |
Palavras-chave: Microcystis aeruginosa; Heterotrophic bacteria; DOM; DON; Nitrates; Ammonia. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00353/46408/46122.pdf |
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