Limits...
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

Dynamics of cell abundances as determined with CytoBuoy's instrument for each resolved cluster. The gray vertical dashed lines materialize the two main precipitation events (Figure 2E) and the black vertical lines the two main NO−3 + NO−2 pulses (Figure 2A). Continuous red lines represent the applied loess to the time series, with its standard error (gray continuous lines). (A) Abundance of PicoFLO cells (103 cells.cm−3). (B) Abundance of picoeukaryote cells (103 cells.cm−3). (C) Abundance of HighSWS cells (103 cells.cm−3). (D) Abundance of HighFLO cells (103 cells.cm−3). (E) Abundance of nanophytoplankton cells (103 cells.cm−3). (F) Abundance of microphytoplankton cells (103 cells.cm−3).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4129916&req=5

Figure 5: Dynamics of cell abundances as determined with CytoBuoy's instrument for each resolved cluster. The gray vertical dashed lines materialize the two main precipitation events (Figure 2E) and the black vertical lines the two main NO−3 + NO−2 pulses (Figure 2A). Continuous red lines represent the applied loess to the time series, with its standard error (gray continuous lines). (A) Abundance of PicoFLO cells (103 cells.cm−3). (B) Abundance of picoeukaryote cells (103 cells.cm−3). (C) Abundance of HighSWS cells (103 cells.cm−3). (D) Abundance of HighFLO cells (103 cells.cm−3). (E) Abundance of nanophytoplankton cells (103 cells.cm−3). (F) Abundance of microphytoplankton cells (103 cells.cm−3).

Mentions: PicoFLO abundance analyzed with the CytoSense flow cytometer varied between 2320 and 39,400 cell.cm−3 (mean: 9583 ± 7401 cells.cm−3; Figure 5A). Synechococcus abundance analyzed with the FACSCalibur flow cytometer ranged from 3223 to 52,810 cell.cm−3 (mean: 28,183 ± 27,688 cells.cm−3; Figure 6A). CytoSense counts were much lower than counts from the FACSCalibur flow cytometer due to the specific CytoSense configuration used during this experiment, in which the photomultiplier tubes were not sensitive enough to detect these dimly fluorescent cells. The correlation between the two instruments regarding these abundance measurements was significant (r = 0.98, n = 6, Pearson, samples from the Cytosense collected within 2 h from the FACSCalibur sampling). Picoeukaryotes abundance varied between 1401 and 40,280 cells.cm−3 (mean: 7875 ± 6508 cells.cm−3, Figure 5B) with the CytoSense instrument, while they varied between 426 and 17,000 cells.cm−3 (mean: 6876 ± 5743 cells.cm−3, Figure 6B) with the FACSCalibur flow cytometer. In this case, abundances were significantly correlated (r = 0.94, n = 6, Pearson). HighSWS abundance was only assessed with the CytoSense instrument, based on their high SWS signature (Figure 3C). Their abundance varied between 15.11 and 256 cells.cm−3 (mean: 65 ± 37 cells.cm−3, Figure 5C). HighFLO cells were detected with the CytoSense instrument only. Their abundance varied between 6 and 1676 cells.cm−3 (mean: 226 ± 275 cells.cm−3, Figure 5D). Nanophytoplankton abundance as recorded by the CytoSense instrument ranged from 495 to 9888 cells.cm−3 (mean: 2260 ± 1631 cells.cm−3, Figure 5E), whereas with the FACSCalibur flow cytometer it varied between 190 and 1728 cells.cm−3 (mean: 703 ± 443 cells.cm−3, Figure 6C). Correlation between the CytoSense and the FACSCalibur flow cytometer regarding nanophytoplankton counts was not significant although values followed similar trends (Figures 5E, 6C). The microphytoplankton cluster was only observed with the CytoSense instrument, with cell abundances between 0 and 103 cells.cm−3 (mean: 17 ± 16 cells.cm−3, Figure 5F).


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)

Dynamics of cell abundances as determined with CytoBuoy's instrument for each resolved cluster. The gray vertical dashed lines materialize the two main precipitation events (Figure 2E) and the black vertical lines the two main NO−3 + NO−2 pulses (Figure 2A). Continuous red lines represent the applied loess to the time series, with its standard error (gray continuous lines). (A) Abundance of PicoFLO cells (103 cells.cm−3). (B) Abundance of picoeukaryote cells (103 cells.cm−3). (C) Abundance of HighSWS cells (103 cells.cm−3). (D) Abundance of HighFLO cells (103 cells.cm−3). (E) Abundance of nanophytoplankton cells (103 cells.cm−3). (F) Abundance of microphytoplankton cells (103 cells.cm−3).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 5: Dynamics of cell abundances as determined with CytoBuoy's instrument for each resolved cluster. The gray vertical dashed lines materialize the two main precipitation events (Figure 2E) and the black vertical lines the two main NO−3 + NO−2 pulses (Figure 2A). Continuous red lines represent the applied loess to the time series, with its standard error (gray continuous lines). (A) Abundance of PicoFLO cells (103 cells.cm−3). (B) Abundance of picoeukaryote cells (103 cells.cm−3). (C) Abundance of HighSWS cells (103 cells.cm−3). (D) Abundance of HighFLO cells (103 cells.cm−3). (E) Abundance of nanophytoplankton cells (103 cells.cm−3). (F) Abundance of microphytoplankton cells (103 cells.cm−3).
Mentions: PicoFLO abundance analyzed with the CytoSense flow cytometer varied between 2320 and 39,400 cell.cm−3 (mean: 9583 ± 7401 cells.cm−3; Figure 5A). Synechococcus abundance analyzed with the FACSCalibur flow cytometer ranged from 3223 to 52,810 cell.cm−3 (mean: 28,183 ± 27,688 cells.cm−3; Figure 6A). CytoSense counts were much lower than counts from the FACSCalibur flow cytometer due to the specific CytoSense configuration used during this experiment, in which the photomultiplier tubes were not sensitive enough to detect these dimly fluorescent cells. The correlation between the two instruments regarding these abundance measurements was significant (r = 0.98, n = 6, Pearson, samples from the Cytosense collected within 2 h from the FACSCalibur sampling). Picoeukaryotes abundance varied between 1401 and 40,280 cells.cm−3 (mean: 7875 ± 6508 cells.cm−3, Figure 5B) with the CytoSense instrument, while they varied between 426 and 17,000 cells.cm−3 (mean: 6876 ± 5743 cells.cm−3, Figure 6B) with the FACSCalibur flow cytometer. In this case, abundances were significantly correlated (r = 0.94, n = 6, Pearson). HighSWS abundance was only assessed with the CytoSense instrument, based on their high SWS signature (Figure 3C). Their abundance varied between 15.11 and 256 cells.cm−3 (mean: 65 ± 37 cells.cm−3, Figure 5C). HighFLO cells were detected with the CytoSense instrument only. Their abundance varied between 6 and 1676 cells.cm−3 (mean: 226 ± 275 cells.cm−3, Figure 5D). Nanophytoplankton abundance as recorded by the CytoSense instrument ranged from 495 to 9888 cells.cm−3 (mean: 2260 ± 1631 cells.cm−3, Figure 5E), whereas with the FACSCalibur flow cytometer it varied between 190 and 1728 cells.cm−3 (mean: 703 ± 443 cells.cm−3, Figure 6C). Correlation between the CytoSense and the FACSCalibur flow cytometer regarding nanophytoplankton counts was not significant although values followed similar trends (Figures 5E, 6C). The microphytoplankton cluster was only observed with the CytoSense instrument, with cell abundances between 0 and 103 cells.cm−3 (mean: 17 ± 16 cells.cm−3, Figure 5F).

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