First estimates of viral impact on bacterial communities in large French alpine lakes Personnic Sébastien 1 Domaizon Isabelle 2 & Jacquet Stéphan 1
(1) INRA - CARRTEL, Group of Aquatic Microbial Ecology (GAME), Thonon les Bains, France (2) Université de Savoie - CARRTEL, Group of Aquatic Microbial Ecology (GAME), Le Bourget du Lac, France
• About the sites Localization, Characteristics
EUROPE
France
Localization, Characteristics Aubonne Morges
Switzerland 100
Venoge Lausanne
300
Veveyse
250 300
Nyon
250 150
50
50
Evian Thonon Dranse
Rhône
Lac supérieure Rhône
Lac inférieure
Genève
0
5
France
Lake Geneva
Altitude Width Length Max. Depth Area Volume Catchments Area Trophic status
372 m 14 km 72 km
309 m 585 km2 86 x109 m3 7,395 km2 Mesotrophic
10 km
Localization, Characteristics
Lake Bourget Altitude Width Length Max. Depth Area Volume Trophic status
232 m 3.5 km 18 km 147 m 44.62 km2 3.6 x109 m3 Mesotrophic
Localization, Characteristics
Lake Annecy Altitude Width Length Max. Depth Area Volume Trophic status
447 m 3,2 km 14,6 km 65 m 28 km2 1.1 x109 m3 Oligotrophic
10 Depth (m)
• Dynamics of microbial communities
20
40
Lake Geneva
0 2e+4 4e+4 6e+4 8e+4 1e+5
30
PE rich synechococcus spp. (cells.ml-1)
50
• 8 depths between 0-50 meters
Depth (m)
10 20 30 40
• 2 samples per month
5000 10000 15000 20000 25000 30000 14000
-1
Small Eukaryotes (cells.ml )
50
• Physical, chemical, ciliates flagellates data not shown Depth (m)
1e+6
20
2e+6
3e+6 4e+6
30 40
5e+6 6e+6 7e+6 8e+6 9e+6
-1
Het. Bacteria (cells.ml )
50
10 Depth (m)
• Flow cytometry counts
10
20 30 40
5e+7 1e+8 2e+8 2e+8
-1
Viruses (part.ml )
50 Nov
May
Nov
2003
May
Nov
2004
May
Nov
2005
10 Depth (m)
• Dynamics of microbial communities
20 0 2e+4 4e+4 6e+4 8e+4 1e+5
30 40
PE rich synechococcus spp. (cells.ml-1)
50
Lake Bourget Depth (m)
10 20
40
• 7 depths between 0-50 meters
5000 10000 15000 20000 25000 30000
30 -1
Small Eukaryotes (cells.ml )
50
• 2 samples per month 1e+6
20
2e+6
3e+6 4e+6
30 40
5e+6 6e+6 7e+6 8e+6 9e+6
-1
Het. Bacteria (cells.ml )
50
10 Depth (m)
• Physical, chemical, ciliates flagellates data not shown
Depth (m)
10
20 30 40
5e+7 1e+8 2e+8 2e+8
-1
Viruses (part.ml )
50 Nov
May
Nov
2003
May
Nov
2004
May
Nov
2005
10 Depth (m)
• Dynamics of microbial communities
20 0 2e+4 4e+4 6e+4 8e+4 1e+5
30 40
-1
PE rich synechococcus spp. (cells.ml ) 50
Lake Annecy Depth (m)
10
• 7 depths between 0-50 meters
20 5000 10000 15000 20000 25000
30 40
-1
Small Eukaryotes (cells.ml )
50
• 2 samples per month • Physical, chemical, ciliates flagellates data not shown Depth (m)
10 20 1e+6 2e+6 3e+6 4e+6 5e+6
30 40
-1
Het. Bacteria (cells.ml )
50
Depth (m)
10 20 30 40
5e+7 1e+8 2e+8 2e+8
Viruses (part.ml-1)
50 Nov
May
Nov
2003
May
Nov
2004
May
Nov
2005
• relationships between microbial communities and environmental parameters ANNECY Lake
BOURGET Lake
1,0
1,0
PC *VLP1 *VLP2
0,5
T°c TOC
VLP1 NH4 VLP2
Factor 2 : 14,89%
Factor 2 : 23,18%
0,5
HB 0,0 Si NO3
T°c TOC Si
0,0
PO4
NO3
AEP Chla
-0,5
PCPO4
-0,5
Exploratory analysis using PCA
HB
AEP Chla
NH4
-1,0
-1,0 -1,0
-0,5
0,0
0,5
1,0
-1,0
-0,5
Factor 1 : 30,80% ANNECY Lake
0,0
0,5
1,0
Factor 1 : 48,95% BOURGET Lake 4
4
Epilimnion June
3
Epilimnion Oct -Nov
Hypolimnion all dates
2
Factor 2: 14,06%
1 Factor 2: 23,18%
Epilimnion end Oct- Nov
2
0
-2
Epilimnion Jul-Sept- early Oct
Hypolimnion all dates
0 -1 May -2
Epilmlinion May -4
-3
Epi - Meta- lmlinion March April May
Epilimnion April - May
-4
-6
-5 -5
-4
-3
-2
-1
0 Factor 1: 30,80%
1
2
3
4
5
-4
-2
0 Factor 1: 48,17%
2
4
6
• 4 groups of VLPs Flow cytometry analysis
Viruses VLP3
VLP4 VLP2 VLP1
Side Scatter
DNA Dye Complex Fluorescence
Heterotrophic BACTERIA
Depth (m)
• Co evolution between VLPs and possible hosts
10
Cells. ml-1
20
1e+6 2e+6 3e+6 4e+6 5e+6 6e+6 7e+6
30 40
Heterotrophic Bacteria 50
10
Part. ml-1
Depth (m)
20
2.0e+7 4.0e+7 6.0e+7 8.0e+7 1.0e+8 1.2e+8
r= 0.48
30
p= 0.03 40
VLP1
n= 21
50 Mar
May
Jul
Sep
Date
Nov
• Co evolution between VLPs and possible hosts
10
Cells. ml-1
20
0 2e+4 4e+4 6e+4 8e+4 1e+5
30 40
Pico nano Cyanobacteria
50
r= 0.49
10
P
