Consulta: creatorFacets:"Rassoulzadegan, F"
Registros recuperados: 4
Data/hora: 01/06/2024 01:24:24

Vertical distribution of pico- and nano-sized Dapi yellow particles at Dyfamed time-series station, NW Mediterranean
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Tanaka, T; Rassoulzadegan, F.
We measured. abundance and surface area of pico- and nano-sized organic particles that are stained by 4'6-diamidino-2-phenylindole (Dapi), namely Dapi yellow particles. This study was done monthly from April 1999 to March 2000 from surface down to 2000 m at the French-JGOFS time-series station Dyfamed in the NW Mediterranean. Dapi yellow particles were always observed throughout the water column and the total surface area of Dapi yellow particles 0.2-10 mum ranged from 0.5 to 51.5 mm(2) l(-1). Dapi yellow particles were generally less abundant in the surface layer, greater between 70 and 500 m and decreased toward 2000 m. During the mixing period, Dapi yellow particles were homogeneous throughout the upper 200 m, suggesting that distribution of Dapi yellow...
Tipo: Text
Palavras-chave: Dapi yellow particles; Matériel organique; Détritus; Méditerranée occidentale; Dapi yellow particles; Organic materials; Detritus; Mediterranean Sea.
Ano: 2003
URL: http://archimer.ifremer.fr/doc/00322/43278/43010.pdf

Elemental composition of individual pico- and nano-sized marine detrital particles in the northwestern Mediterranean Sea
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Mostajir, B; Fagerbakke, Km; Heldal, M; Thingstad, Tf; Rassoulzadegan, F.
The elemental composition of individual &lt; 10 mu m detrital particles from Mediterranean surface waters was analysed using a Transmission Electron Microscope (TEM) equipped with an energy dispersive X-Ray microanalyser. Results show that carbon and phosphorus content per detritus volume are much higher in pico-detrital particles &lt; 2 mu m (42 kg C m(-3) and 1 kg P m(-3)) than in 5-10 mu m detrital particles (20 kg C m-3 and 0.1 kg P m(-3)). The C:N:P atomic ratios for different sized fractions of the detrital particles were found to be 82:10:1 for &lt; 2 mu m particles, 120:29:1 for 2-5 mu m particles and 308:37:1 for 5-10 mu m particles. The average ratio for all size classes of detrital particles (&lt; 10 mu m) was 132:23:1. The differences in...
Tipo: Text
Palavras-chave: Détritus; Composition élémentaire; Microscope électronique à transmission; Rayons X; Méditerranée; Detritus; Elemental composition; TEM; X-ray; Mediterranean.
Ano: 1998
URL: http://archimer.ifremer.fr/doc/00325/43661/43208.pdf

Pigment dynamics associated with the grazing of a ciliate and a flagellate feeding on a cyanobacterium
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Mostajir, B; Bustillos-guzman, J; Claustre, H; Rassoulzadegan, F.
The egestion of particulate material as well as pigment degradation during microzooplankton grazing on phytoplankton are poorly known processes. In an attempt to evaluate these processes, changes in pigment concentrations within various size fractions were monitored in batch cultures of an assemblage of a pelagic ciliate (Strombidium sulcatum) and a heterotrophic flagellate (Paraphysomonas sp.) feeding on a cyanobacterium (Synechococcus sp.) over a 10-day period. Chlorophyll a, carotenoids and phaeopigments were not found in the 0.1-0.7 mu m fraction while the pigments originally in the 0.7-3.0 mu m fraction (prey) were transferred into the &gt; 3.0 mu m size fraction (predator). During this transfer, the carotenoids (zeaxanthin and B-carotene) were not...
Tipo: Text
Palavras-chave: Pigment; Phéopigment; Broutage; Protozoaire; HPLC; Pigment; Phaeopigment; Grazing; Protozoa; HPLC.
Ano: 1998
URL: http://archimer.ifremer.fr/doc/00325/43660/43209.pdf

Release of dissolved amino acids by flagellates and ciliates grazing on bacteria
Provedor de dados: Institutional Archive of Ifreme (ArchiMer)
Autores: Ferrier-pages, C; Karner, M; Rassoulzadegan, F.
Release of amino acids was examined in the laboratory in the form of dissolved primary amine (DPA) by two marine planktonic protozoa (the oligotrichous ciliate, Strombidium sulcatum and the aplastidic flagellate Pseudobodo sp.) grazing on bacteria. DPA release rates were high (19-25 x 10(-6) and 1.8-2.3 x 10(-6) mu mol DPA cell(-1) h(-1) for flagellates and ciliates, respectively) during the exponential phase, when the ingestion rates were maximum. Release rates were lower during the other growth phases. The release of DPA accounted for 10 % (flagellates) and 16 % (ciliates) of the total nitrogen ingested. Our data suggest that the release of DPA by protozoa could play an important role in supporting bacterial and consequently autotrophic pico- and...
Tipo: Text
Palavras-chave: Acides aminés; Protozoaires; Taux d'excrétion; Matière organique dissoute; Amino acids; Protozoa; Excretion rates; Dissolved organic matter.
Ano: 1998
URL: http://archimer.ifremer.fr/doc/00326/43670/43200.pdf