Supporting figures S1, S2 and S3 to:

Interspecific protection against oxidative stress:

green algae protect harmful cyanobacteria against hydrogen peroxide

Erik F.J. Weenink1, Hans C.P. Matthijs1†, J. Merijn Schuurmans1, Tim Piel1, Maria J. van Herk1,

Corrien A.M. Sigon1, Petra M. Visser1 and Jef Huisman1

1Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics,

University of Amsterdam, P.O. Box 94240, 1090 GE Amsterdam, The Netherlands.

Minimum fluorescence (F0) Maximum fluorescence (Fm)

Microcystis

0

200

400

600

800 Microcystis

Anabaena

0

100

200

300

400 Anabaena

Flu

ores

cenc

e (A

U)

0 mg L-1 1 mg L-1 2 mg L-1 3.5 mg L-1 5 mg L-1 8 mg L-1 12 mg L-1

0 5 10 15 20 25

Planktothrix

0

300

600

900

1200

1500

0 5 10 15 20 25

Planktothrix

Time after H2O2 addition (hour)

Fig. S1. Minimum fluorescence (F0) and maximum fluorescence (Fm) in monocultures

of three species of freshwater cyanobacteria: Microcystis aeruginosa strain PCC

7806, Anabaena PCC 7938 and Planktothrix PCC 7811, after addition of different

H2O2 concentrations.

Chlorella

0

500

1000

1500

2000 Chlorella

Desmodesmus

0

200

400

600

800

1000 Desmodesmus

0 5 10 15 20 25

Kirchneriella

0

250

500

750

1000

1250

0 5 10 15 20 25

Kirchneriella

0 mg L-1 12 mg L-1 20 mg L-1 35 mg L-1 50 mg L-1 75 mg L-1 100 mg L-1

Time after H2O2 addition (hour)

Flu

ores

cenc

e (A

U)

Minimum fluorescence (F0) Maximum fluorescence (Fm)

Fig. S2. Minimum Fluorescence (F0) and maximum fluorescence (Fm) in monocultures of

six species of fresh-water green algae: Chlorella sorokiniana SAG 211-8k, Desmodesmus

armatus SAG 276-4e, Kirchneriella contorta SAG 11.81, Ankistrodesmus falcatus SAG

202-9, Monoraphidium graffithii SAG 202-13 and Chlamydomonas reinhardtii SAG 77.81,

after addition of different H2O2 concentrations.

0 mg L-1 12 mg L-1 20 mg L-1 35 mg L-1 50 mg L-1 75 mg L-1 100 mg L-1

Ankistrodesmus

0

300

600

900

1200

1500 Ankistrodesmus

Monoraphidium

0

300

600

900

1200

1500 Monoraphidium

0 5 10 15 20 25

Chlamydomonas

0

400

800

1200

1600

0 5 10 15 20 25

Chlamydomonas

Time after H2O2 addition (hour)

Flu

ores

cenc

e (A

U)

Minimum Fluorescence (F0) Maximum Fluorescence (Fm)

Fig. S2. (continued)

spent medium Chlorella b

0 1 2 3

spent medium Microcystis d

0

5

10

15

20 a lysate Chlorella

0

5

10

15

20

0 1 2 3

c lysate Microcystis

H2O

2 con

cent

ratio

n (m

g L-

1 )

Time after H2O2 addition (hours)

2.5 (mg/l) 5 (mg/l) 10 (mg/l) 15 (mg/l) 20 (mg/l) 2.5 mg L-1 20 mg L-15 mg L-1 10 mg L-1 15 mg L-1

Fig. S3. H2O2 degradation by the lysate and spent medium is slow in the absence of intact

cells of Chlorella and Microcystis. Graphs show H2O2 degradation by the lysate and spent

medium of both Chlorella and Microcystis, during the first 3 hours after addition of different

H2O2 concentrations.