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Onset of the spring bloom in the northwestern Mediterranean Sea: influence of environmental pulse events on the in situ hourly-scale dynamics of the phytoplankton community structure.

Thyssen M, Grégori GJ, Grisoni JM, Pedrotti ML, Mousseau L, Artigas LF, Marro S, Garcia N, Passafiume O, Denis MJ - Front Microbiol (2014)

Bottom Line: The third abundance pulse could be considered as the spring bloom commonly observed in the area.The high frequency data-set made it possible to study the phytoplankton cell cycle based on daily cycles of forward scatter and abundance.The combination of daily cell cycle, abundance trends and environmental pulses will open the way to the study of phytoplankton short-term reactivity to environmental conditions.

View Article: PubMed Central - PubMed

Affiliation: CNRS/INSU, IRD, Mediterranean Institute of Oceanography, Aix Marseille Université Marseille, France.

ABSTRACT
Most of phytoplankton influence is barely understood at the sub meso scale and daily scale because of the lack of means to simultaneously assess phytoplankton functionality, dynamics and community structure. For a few years now, it has been possible to address this objective with an automated in situ high frequency sampling strategy. In order to study the influence of environmental short-term events (nutrients, wind speed, precipitation, solar radiation, temperature, and salinity) on the onset of the phytoplankton bloom in the oligotrophic Bay of Villefranche-sur-Mer (NW Mediterranean Sea), a fully remotely controlled automated flow cytometer (CytoSense) was deployed on a solar-powered platform (EOL buoy, CNRS-Mobilis). The CytoSense carried out single-cell analyses on particles (1-800 μm in width, up to several mm in length), recording optical pulse shapes when analyzing several cm(3). Samples were taken every 2 h in the surface waters during 2 months. Up to 6 phytoplankton clusters were resolved based on their optical properties (PicoFLO, Picoeukaryotes, Nanophytoplankton, Microphytoplankton, HighSWS, HighFLO). Three main abundance pulses involving the 6 phytoplankton groups monitored indicated that the spring bloom not only depends on light and water column stability, but also on short-term events such as wind events and precipitation followed by nutrient pulses. Wind and precipitation were also determinant in the collapse of the clusters' abundances. These events occurred within a couple of days, and phytoplankton abundance reacted within days. The third abundance pulse could be considered as the spring bloom commonly observed in the area. The high frequency data-set made it possible to study the phytoplankton cell cycle based on daily cycles of forward scatter and abundance. The combination of daily cell cycle, abundance trends and environmental pulses will open the way to the study of phytoplankton short-term reactivity to environmental conditions.

No MeSH data available.


Related in: MedlinePlus

Cytogram from the FACSCalibur flow cytometer with red fluorescence [FLR3 (a.u.)] vs. sideward scatter (SSC-H) showing the Prochlorococcus (not discussed in this paper), Synechococcus, picoeukaryotes and nanophytoplankton clusters.
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Figure 4: Cytogram from the FACSCalibur flow cytometer with red fluorescence [FLR3 (a.u.)] vs. sideward scatter (SSC-H) showing the Prochlorococcus (not discussed in this paper), Synechococcus, picoeukaryotes and nanophytoplankton clusters.

Mentions: As regards conventional flow cytometry, four ultraphytoplankton groups were distinguished with the FACSCalibur flow cytometer over the study period on the basis of their optical signals (Li, 1994). Synechococcus (<1.5 μm) cells were resolved by their signature in a cytogram of red fluorescence (FL3, >620 nm) vs. orange fluorescence represented by phycoerythrin-containing pigment (FL2, 565–592 nm wavelength range). The Prochlorococcus (<1 μm) cluster exhibits smaller scatter intensities than Synechococcus, a lower red fluorescence signal and no orange fluorescence signal. Data from this latter group are not included in this paper. Picoeukaryotes (<2 μm) and nanophytoplankton (2–10 μm) cells were resolved in red fluorescence vs. side scatter plots (Figure 4).


Onset of the spring bloom in the northwestern Mediterranean Sea: influence of environmental pulse events on the in situ hourly-scale dynamics of the phytoplankton community structure.

Thyssen M, Grégori GJ, Grisoni JM, Pedrotti ML, Mousseau L, Artigas LF, Marro S, Garcia N, Passafiume O, Denis MJ - Front Microbiol (2014)

Cytogram from the FACSCalibur flow cytometer with red fluorescence [FLR3 (a.u.)] vs. sideward scatter (SSC-H) showing the Prochlorococcus (not discussed in this paper), Synechococcus, picoeukaryotes and nanophytoplankton clusters.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4129916&req=5

Figure 4: Cytogram from the FACSCalibur flow cytometer with red fluorescence [FLR3 (a.u.)] vs. sideward scatter (SSC-H) showing the Prochlorococcus (not discussed in this paper), Synechococcus, picoeukaryotes and nanophytoplankton clusters.
Mentions: As regards conventional flow cytometry, four ultraphytoplankton groups were distinguished with the FACSCalibur flow cytometer over the study period on the basis of their optical signals (Li, 1994). Synechococcus (<1.5 μm) cells were resolved by their signature in a cytogram of red fluorescence (FL3, >620 nm) vs. orange fluorescence represented by phycoerythrin-containing pigment (FL2, 565–592 nm wavelength range). The Prochlorococcus (<1 μm) cluster exhibits smaller scatter intensities than Synechococcus, a lower red fluorescence signal and no orange fluorescence signal. Data from this latter group are not included in this paper. Picoeukaryotes (<2 μm) and nanophytoplankton (2–10 μm) cells were resolved in red fluorescence vs. side scatter plots (Figure 4).

Bottom Line: The third abundance pulse could be considered as the spring bloom commonly observed in the area.The high frequency data-set made it possible to study the phytoplankton cell cycle based on daily cycles of forward scatter and abundance.The combination of daily cell cycle, abundance trends and environmental pulses will open the way to the study of phytoplankton short-term reactivity to environmental conditions.

View Article: PubMed Central - PubMed

Affiliation: CNRS/INSU, IRD, Mediterranean Institute of Oceanography, Aix Marseille Université Marseille, France.

ABSTRACT
Most of phytoplankton influence is barely understood at the sub meso scale and daily scale because of the lack of means to simultaneously assess phytoplankton functionality, dynamics and community structure. For a few years now, it has been possible to address this objective with an automated in situ high frequency sampling strategy. In order to study the influence of environmental short-term events (nutrients, wind speed, precipitation, solar radiation, temperature, and salinity) on the onset of the phytoplankton bloom in the oligotrophic Bay of Villefranche-sur-Mer (NW Mediterranean Sea), a fully remotely controlled automated flow cytometer (CytoSense) was deployed on a solar-powered platform (EOL buoy, CNRS-Mobilis). The CytoSense carried out single-cell analyses on particles (1-800 μm in width, up to several mm in length), recording optical pulse shapes when analyzing several cm(3). Samples were taken every 2 h in the surface waters during 2 months. Up to 6 phytoplankton clusters were resolved based on their optical properties (PicoFLO, Picoeukaryotes, Nanophytoplankton, Microphytoplankton, HighSWS, HighFLO). Three main abundance pulses involving the 6 phytoplankton groups monitored indicated that the spring bloom not only depends on light and water column stability, but also on short-term events such as wind events and precipitation followed by nutrient pulses. Wind and precipitation were also determinant in the collapse of the clusters' abundances. These events occurred within a couple of days, and phytoplankton abundance reacted within days. The third abundance pulse could be considered as the spring bloom commonly observed in the area. The high frequency data-set made it possible to study the phytoplankton cell cycle based on daily cycles of forward scatter and abundance. The combination of daily cell cycle, abundance trends and environmental pulses will open the way to the study of phytoplankton short-term reactivity to environmental conditions.

No MeSH data available.


Related in: MedlinePlus