Enumeration of Phytoplankton, Bacteria, and Viruses in Marine Samples

Marie, Dominique; Partensky, Frédéric; Vaulot, Daniel; Brussaard, Corina P. D.

doi:10.1002/0471142956.cy1111s10

Cited by 302 publications

(293 citation statements)

References 32 publications

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“…Samples (1-2 ml) for flow cytometry were collected each day 0.5-1.5 h after the start of the light period and preserved in 1% buffered paraformaldehyde and 0.05% glutaraldehyde, incubated 20-30 min, flash frozen in liquid nitrogen and stored at − 80°C (Marie et al, 1999). Samples (1-2 ml) for epifluorescence microscopy were taken from a single replicate of each sample and were preserved in 8-9 ml Aquil with 2% glutaraldehyde and stored in the dark at 4°C.…”

Section: Co-culture Experimentsmentioning

confidence: 99%

Ubiquitous marine bacterium inhibits diatom cell division

Tol

Amin²,

Armbrust

2016

The ISME Journal

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Intricate relationships between microorganisms structure the exchange of molecules between taxa, driving their physiology and evolution. On a global scale, this molecular trade is an integral component of biogeochemical cycling. As important microorganisms in the world's oceans, diatoms and bacteria have a large impact on marine biogeochemistry. Here, we describe antagonistic effects of the globally distributed flavobacterium Croceibacter atlanticus on a phylogenetically diverse group of diatoms. We used the model diatom Thalassiosira pseudonana to study the antagonistic impact in more detail. In co-culture, C. atlanticus attaches to T. pseudonana and inhibits cell division, inducing diatom cells to become larger and increase in chlorophyll a fluorescence. These changes could be explained by an absence of cytokinesis that causes individual T. pseudonana cells to elongate, accumulate more plastids and become polyploid. These morphological changes could benefit C. atlanticus by augmenting the colonizable surface area of the diatom, its photosynthetic capabilities and possibly its metabolic secretions.

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Section: Co-culture Experimentsmentioning

confidence: 99%

Ubiquitous marine bacterium inhibits diatom cell division

Tol

Amin²,

Armbrust

2016

The ISME Journal

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“…The photoautotrophic cells (<20 µm) were counted fresh and discriminated by their pigment autofluorescence (Marie et al, 1999). Only eukaryotic photosynthetic organisms were detected.…”

Section: Microbial Abundancesmentioning

confidence: 99%

“…Net growth and loss rates of phytoplankton were derived from exponential regression analysis of the cell abundances. The abundances of heterotrophic prokaryotes and viruses were determined from fixed, frozen samples according to Marie et al (1999) and Brussaard (2004), respectively. In short, thawed samples were diluted with Tris-EDTA buffer (10 mM Tris-HCl and 1 mM EDTA, pH 8) and stained with the green fluorescent nucleic acid-specific dye SYBR-Green I (Molecular Probes, Invitrogen Inc.), for a final concentration of 1 × 10 −4 (HP) or 0.5 × 10 −4 (viruses) of the commercial stock, in the dark at room temperature for 15 and 10 min, respectively.…”

Section: Microbial Abundancesmentioning

confidence: 99%

Arctic microbial community dynamics influenced by elevated CO2 levels

et al. 2013

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Abstract. The Arctic Ocean ecosystem is particularly vulnerable to ocean acidification (OA) related alterations due to the relatively high CO2 solubility and low carbonate saturation states of its cold surface waters. Thus far, however, there is only little known about the consequences of OA on the base of the food web. In a mesocosm CO2-enrichment experiment (overall CO2 levels ranged from ~ 180 to 1100 μatm) in Kongsfjorden off Svalbard, we studied the consequences of OA on a natural pelagic microbial community. OA distinctly affected the composition and growth of the Arctic phytoplankton community, i.e. the picoeukaryotic photoautotrophs and to a lesser extent the nanophytoplankton thrived. A shift towards the smallest phytoplankton as a result of OA will have direct consequences for the structure and functioning of the pelagic food web and thus for the biogeochemical cycles. Besides being grazed, the dominant pico- and nanophytoplankton groups were found prone to viral lysis, thereby shunting the carbon accumulation in living organisms into the dissolved pools of organic carbon and subsequently affecting the efficiency of the biological pump in these Arctic waters.

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“…Chla was extracted in 100% acetone and then determined by a reverse-phase high-performance liquid chromatography (HPLC) (Barlow, et al, 1997). Samples for enumeration of bacteria were fixed with glutaraldehyde (0.5% final concentration), stained with SYBR Green I (Molecular Probes Inc., Eugene, OR), and counted by a flow cytometer (FACSCalibur, Becton Dickinson, Franklin Lakes, NJ) equipped with an air-cooled laser providing 15 mW at 488 nm and with standard filter set-up (Marie, et al, 1999). Bacterial abundance and Chl-a were converted to Cbiomass under the assumption that bacterial carbon content is 20 fg C cell −1 (Lee and Fuhrman, 1987) and C: Chl-a is 30 (w:w), respectively.…”

Section: Dissolved and Particulate Nutrientsmentioning

confidence: 99%

Availability of phosphate for phytoplankton and bacteria and of glucose for bacteria at different pCO2 levels in a mesocosm study

et al. 2008

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Abstract. Availability of phosphate for phytoplankton and bacteria and of glucose for bacteria at different pCO 2 levels were studied in a mesocosm experiment (PeECE III). Using nutrient-depleted SW Norwegian fjord waters, three different levels of pCO 2 (350 µatm: 1×CO 2 ; 700 µatm: 2×CO 2 ; 1050 µatm: 3×CO 2 ) were set up, and nitrate and phosphate were added at the start of the experiment in order to induce a phytoplankton bloom. Despite similar responses of total particulate P concentration and phosphate turnover time at the three different pCO 2 levels, the size distribution of particulate P and 33 PO 4 uptake suggested that phosphate transferred to the >10 µm fraction was greater in the 3×CO 2 mesocosm during the first 6-10 days when phosphate concentration was high. During the period of phosphate depletion (after Day 12), specific phosphate affinity and specific alkaline phosphatase activity (APA) suggested a P-deficiency (i.e. suboptimal phosphate supply) rather than a P-limitation for the phytoplankton and bacterial community at the three different pCO 2 levels. Specific phosphate affinity and specific APA tended to be higher in the 3×CO 2 than in the 2×CO 2 and 1×CO 2 mesocosms during the phosphate depletion period, although no statistical differences were found. Glucose turnover time was correlated significantly and negatively with bacterial abundance and production but not with the bulk DOC concentration. This suggests that even though constituting a small fraction of the bulk DOC, glucose was an important component of labile DOC for bacteria. SpecificCorrespondence to: T. Tanaka (tsuneo.tanaka@univmed.fr) glucose affinity of bacteria behaved similarly at the three different pCO 2 levels with measured specific glucose affinities being consistently much lower than the theoretical maximum predicted from the diffusion-limited model. This suggests that bacterial growth was not severely limited by the glucose availability. Hence, it seems that the lower availability of inorganic nutrients after the phytoplankton bloom reduced the bacterial capacity to consume labile DOC in the upper mixed layer of the stratified mesocosms.

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Enumeration of Phytoplankton, Bacteria, and Viruses in Marine Samples

Cited by 302 publications

References 32 publications

Ubiquitous marine bacterium inhibits diatom cell division

Ubiquitous marine bacterium inhibits diatom cell division

Arctic microbial community dynamics influenced by elevated CO<sub>2</sub> levels

Availability of phosphate for phytoplankton and bacteria and of glucose for bacteria at different <i>p</i>CO<sub>2</sub> levels in a mesocosm study

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Enumeration of Phytoplankton, Bacteria, and Viruses in Marine Samples

Cited by 302 publications

References 32 publications

Ubiquitous marine bacterium inhibits diatom cell division

Ubiquitous marine bacterium inhibits diatom cell division

Arctic microbial community dynamics influenced by elevated CO&lt;sub&gt;2&lt;/sub&gt; levels

Availability of phosphate for phytoplankton and bacteria and of glucose for bacteria at different &lt;i&gt;p&lt;/i&gt;CO&lt;sub&gt;2&lt;/sub&gt; levels in a mesocosm study

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Arctic microbial community dynamics influenced by elevated CO<sub>2</sub> levels

Availability of phosphate for phytoplankton and bacteria and of glucose for bacteria at different <i>p</i>CO<sub>2</sub> levels in a mesocosm study