Global environmental change

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Global environmental change

Kruse 500 µM

200 µM 200 µM

Balsam Al-Janabi, Inken Kruse and Martin Wahl

GEOMAR, Helmholtz Center for Ocean Research, Kiel, Germany

The interaction between intraspecific genetic diversity and global environmental change in early life-stage Fucus vesiculosus

©B. Al-Janabi

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Global change impact on Fucus vesiculosus

Main driver: Ocean acidification, warming

Other environmental changes: Eutrophication, hypoxic areas, upwelling events, pollution…

F. vesiculosus can buffer adverse environmental changes

Populations: evolutionary adaptation or range shifts= expansions and retractions The combined effect of multiple stressors will impact marine populations

Wahl et al. 2015 Perspectives in Phycology

Investigations have often been limited regarding: single stressors, ontogenic stages, constant conditions, one season…

Wahl et al. 2015 Marine and Freshwater Research

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Confers potential for adaptation through selection Allows for resilience and ecosystem services

Hypothesis: Populations of high genetic diversity perform better on environmental stress.

Diversity

Genetic diversity of Fucus vesiculosus

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© K. Maczassek

Diversity level 2

2x

Collection of fertile adult Fucus vesiculosus Induction of gamete release

Settling of germlings on limestones cubes: edge length 2 cm.

4x

1x

Genetic diversity of Fucus vesiculosus

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versus

1 2 3 4 5 6 7 8

offspring of 1 parental pair each

offspring of 2 parental pairs each

offspring of 4 parental pairs each

1, 2 3, 4 5, 6 7, 8

5, 6, 7 , 8 1, 2, 3, 4

versus

5

Diversity level

Low

Medium

High

Three levels of genetic diversity

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Investigation of species interactions and community structure under climate change Upscaling of: Multiple factors, Multi-species communities, Multi-seasonalapproach

Closing the gap between laboratory and field experiments Flow-through system allows a near natural scenario

Wahl et al. 2015 Limnology and Oceanography: Methods 6

Climate change scenario: Kiel Benthocosms

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Temperature: + 5 °C pCO

₂

: 1100 µatm

7

4 treatment levels

High Temperature + pCO

₂

High Temperature

High pCO

₂

Ambient (Fjord conditions) n = 3

Seasonal variation - 2013

Warming and acidification: natural conditions

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Seasonal differences between spring and summer (p-value < 0.05)

Season *

0 20 40 60 80 100

Spring13 Summer Autumn Winter Spring14

Survival % ^T+CO2+_{T+ CO2-}

T- CO2+

T- CO2-

Warming decreases survival in summer and also in winter (p-value < 0.05)

Means +SD n=3

Temp * Temp *

8

Warming and OA impacts depend on the season

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0 0,2 0,4 0,6 0,8 1

Area (mm2)

380 1120 2400

pCO₂effect on growth

High pCO₂ levels increase growth of Fucus germlings (p-value < 0.05) = fertilisation effect

Means +SD n=3

Acidification effects on growth: laboratory conditions

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-2 -1 0 1 2

1 2 3 4 5 6 7 8

Survival %

log effect ratio (SD) (relative to “ambient”)

T+/ T- CO₂ +/ CO₂ - Future/ Present Temp

CO₂ Temp

Temp CO₂

Siblings vary in their response to warming and acidification

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0 20 40 60 80 100

T+ CO2+ T+ CO2- T- CO2-

Survival%

Autumn

0 20 40 60 80 100

T+ CO2+ T+ CO2- T- CO2-

Survival%

Winter

DL 1 DL 2 DL 3

Means +SD n=3

Survival high diversity level

>

survival low diversity level at high temperatures (p-value < 0.05)

Increased survival for a group of high diversity level indicated facilitation processes among different genotypes

Diversity level low

medium high

Higher diversity level survive better under warming

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Temperature: + 5 °C

pCO

₂

: 1100 µatm

[Temperature + pCO

₂

] x ^Nutrients

[NO

₂

NO

₃

PO

₄

]

12

Warming, acidification and nutrient enrichment

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0 0,5 1 1,5 2 2,5 3 3,5

T-CO2-N- T-CO2-N+ T+CO2+ N- T+CO2+ N+

Growth % d-1

0 20 40 60 80 100

T-CO2-N- T-CO2-N+ T+CO2+ N- T+CO2+ N+

Survival %

TempCO₂- N- TempCO₂- N+ TempCO₂+ N- TempCO₂+ N+

***

Warming during a heat wave decreased survival and growth significantly (p < 0.0001)

Nutrient enrichment attenuates the high mortality and growth reduction (p < 0.0001)

Warming+Acidification interacts with the factor nutrients (p <

0.0001)

+N

+N +T

+T

Nutrient enrichment mitigates heat wave stress

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[Temperature + pCO

₂

] x ^Nutrients

[NO₂ NO₃ PO₄] + [Temperature + pCO₂] + Nutrients

+ [Temperature + pCO₂] - Nutrients - [Temperature + pCO₂] + Nutrients - [Temperature + pCO₂] - Nutrients

3 days Upwelling

14

Local Upwelling event

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Mortality of F. vesiculosus germlings is strongly increased under hypoxia in all groups of pre-treatments

Previous exposure to warming and acidification decreased the toleranceto

hypoxia stress (p < 0.001) ¹⁵

0 20 40 60 80 100

TCO2- N- TCO2- N+ TCO2+ N- TCO2+ N+

Mortality %

Pre-treatment TempCO₂- N- TempCO₂- N+ TempCO₂+ N- TempCO₂+ N+

3 days Hypoxia

Sensitivity to hypoxia is enhanced by previous warming

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Vinebrook et al. (2004) OIKOS

Populations resistance to multiple factors depend on trade correlation

Analysis of sibling groups sensitivity towards multiple stressors was performed

Sibling groups sensitivity to stressor A and stressor B may correlate genotypic correlations

Sibling groups were ranked according to the different sensitivities:

Warming Acidification

Warming + acidification

Hypoxia

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Genotypic correlations determine the direction of selection

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0 1 2 3 4 5 6 7 8

6 4

8

3 1

7 5

2

0 1 2 3 4 5 6 7

5

4

6

1

3

7

8

Survival

0 1 2 3 4 5 6 7 8

R= 0.929 P= 0.0022 6

4 8

1

3

7

5

Growth 2

Rank sensitivity to acidification

Rank sensitivity to warming

Spring

R= 0.952 P= 0.0011

SpringSummer

R= 0.821 P= 0.0341

Growth

Sensitivity to warming and acidification is positively correlated (p < 0.05)

Direction of selection goes towards the more tolerant genotypes to warming and acidification

Positive correlation will accelerate selection processes towards these genotypes

17

Siblings correlations of sensitivities to warming and OA

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0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

SensitivitytoTempCO 2

Sensitivity to Hypoxia

6 10

4

9

16 5

8

13 11

14 1

3 2

15 12

7

R = - 0.8088 P = 0.0002

Sensitivity towards warming+acidification and hypoxia is negatively correlated

(p < 0.001)

Genotypes adapted to warming and

acidification are most sensitive to hypoxia

Correlations of sensitivities to OAW and hypoxia

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• Warming enhances growth in summer, but reduces survival in late summer

= seasonal variation

• Sibling groups vary in their response to warming and acidification -> potential for adaptation

• Heat wave stress is mitigated under nutrient enrichment but enhances the sensitivity to hypoxia

• Positive correlation of sensitivities towards warming and acidification determines the direction of selection

• Populations adapted to warming and acidification are most sensitive to hypoxic upwelling

Conclusions

• An upscaling is required: number of stressors, natural fluctuations, ontogenic stages, no of seasons; to predict impacts on marine populations

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Acknowledgements

Martin Wahl Inken Kruse

Angelika Graiff Ulf Karsten Björn Buchholz

Federal Ministry of Education and Research

baljanabi@geomar.de

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Acknowledgements

Thank you for your attention!

500 µM

Global environmental change