Key players of the phytoplankton communities
50 µm
50 µm
5 µm
5 µm
50 µm
0.5 µm
Key players of the phytoplankton communities
Key players of the phytoplankton communities
A11
KERFIX
D2
D3
D4
D5
D6
C11
A5
D1
M2
B11
A1
B1
C1
Key players of the phytoplankton communities
Kopczynska E.E., Fiala M., and Jeandel C., Annual and interannual
variability in phytoplankton at a permanent station off Kerguelen
Islands, Southern Ocean, Polar Biology, 20 (5), 342-351, 1998.
Total cell Carbon, µg L-1
M2
8
6
4
2
0
N D J F M A M J Jt A S O N D J F M A M J Jt A S O N D J F
1992
1994
1993
1995
Algal groups
as % of total cell C
Key players of the phytoplankton communities
100
80
60
40
20
Total cell Carbon, µg L-1
0
Kopczynska et al., 1998
8
6
4
2
0
N D J F M A M J Jt A S O N D J F M A M J Jt A S O N D J F
1992
1994
1993
1995
Algal groups
as % of total cell C
Key players of the phytoplankton communities
100
80
60
40
20
0
N D J F M A M J Jt A S O N D J F M A M J Jt A S O N D J F
1992
1994
1993
1995
Kopczynska et al., 1998
Diatoms
total Dinoflagellates
naked flagellates
picoplankton
Coccolithophorids
Algal groups
as % of total cell C
Key players of the phytoplankton communities
100
80
60
40
20
0
N D J F M A M J Jt A S O N D J F M A M J Jt A S O N D J F
1992
1994
1993
1995
Kopczynska et al., 1998
Diatoms
• low contribution
• dominant species : Fragilariopsis kerguelensis,
Thalassionema nitzschioides
Algal groups
as % of total cell C
Key players of the phytoplankton communities
100
80
60
40
20
0
N D J F M A M J Jt A S O N D J F M A M J Jt A S O N D J F
1992
1994
1993
1995
Kopczynska et al., 1998
total Dinoflagellates
• highest contribution
• dominant species : Prorocentrum spp., Gymnodinium
spp., heterotrophic species of Protoperidium spp. and
Gyrodinium spp. during summer.
Algal groups
as % of total cell C
Key players of the phytoplankton communities
100
80
60
40
20
0
N D J F M A M J Jt A S O N D J F M A M J Jt A S O N D J F
1992
1994
1993
1995
Kopczynska et al., 1998
naked flagellates
• low contribution during biomass peaks
• dominant groups : Prymnesiophyceae (Chrysochromulina
spp.), Prasinophyceae (Pyramimonas spp.), and
Cryptophyceae (Hillea fusiformis)
Algal groups
as % of total cell C
Key players of the phytoplankton communities
100
80
60
40
20
0
N D J F M A M J Jt A S O N D J F M A M J Jt A S O N D J F
1992
1994
1993
1995
Kopczynska et al., 1998
Coccolithophorids
• occasionally abundant
• dominant species :
Emiliania huxleyi
Key players of the phytoplankton communities
Surface temperatures (> 2°C) are compatible with
Emiliania huxleyi and Fragilariopsis kerguelensis
Key players of the phytoplankton communities
Blain S., Tréguer P., Belviso S., Bucciarellia E., Denis M., Desabre S.,
Fiala M., Martin Jézéquel V., Le Fèvre J., Mayzaud P., Marty J.-C.,
and Razouls S., A biogeochemical study of the island mass effect in
the context of the iron hypothesis: Kerguelen Islands, Southern
Ocean, Deep-Sea Research, 48 (1), 163-187, 2001.
M2
Key players of the phytoplankton communities
Blain et al., 2001 – 4-10 October 1995
Key players of the phytoplankton communities
Objective 3 : Knowledge and quantification of biogeochemical
processes and their responses to changes in the forcing
parameters.
3.1) Structure of phytoplankton communities. KEOPS will address the question "what
physical and chemical factors regulate phytoplankton growth and species composition?"
3.2) Shifts in the structure of the phytoplankton communities in response to changes in the
forcing parameters. (KEOPS will focus on the following forcing parameters: iron, light
(visible and UV), stratification.
3.3) Do biological activity compete with photochemical processes for the production of
biogenic gases and iron speciation?
Key players of the phytoplankton communities
Objective 3 : Knowledge and quantification of biogeochemical
processes and their responses to changes in the forcing
parameters.
3.1) Structure of phytoplankton communities. KEOPS will address the question "what
physical and chemical factors regulate phytoplankton growth and species composition?"
Detailed topics include:
3.1.1) Characterization of phytoplankton communities in contrasted environments.
Special attention will be paid to the major biogeochemical players: diatoms,
Phaeocystis, coccolithophorids, cryptophyceans and picoplankton.
3.1.2) Identification, hierarchisation, and parameterization of the processes that control
the structure of the phytoplankton communities.
3.1.3) Impact of the structure of the phytoplankton community on the fluxes of chemical
compounds that are relevant for climate.
3.1.4) Impact of the structure of the phytoplankton community on the flux of carbon
exported below the depth of the mixed layer
Key players of the phytoplankton communities
Objective 3 : Knowledge and quantification of biogeochemical
processes and their responses to changes in the forcing
parameters.
3.2) Shifts in the structure of the phytoplankton communities in response to changes in the
forcing parameters. (KEOPS will focus on the following forcing parameters: iron, light
(visible and UV), stratification. The processes will be investigated mainly in the surface
layer.
3.2.1) How will the forcing parameters impact the processes controlling the production
of chemical compounds that are relevant for climate?
3.2.2) How will the forcing parameters impact the processes controlling the export of
carbon below the depth of the mixed layer?
3.2.3) What is the feedback of biological activity on iron speciation?