The environmental responses of harmful algae known to ...

The environmental responses of harmful algae known to impact aquaculture species along the

French Atlantic and English Channel coasts

Content

I. Climate change and HAB an aquaculture

II. Niche and subniche concept

III. The thesis results

IV.Application to the post-doc

Global change

Global warming

Human impact

Human directly effect on food web

Human impact

=

Agriculture Nitrogen (N) Phosphate (P)

Eutrophication

Human impact

Harmful algae

Problematic

What is/are the real cause(s) of Harmful Algae Bloom (HAB)?

“The response of harmful algal blooms to the multifaceted forcing of projected climate change is largely unknown and

highly speculative.” (Wells et al., 2015)

Problematic

“[…] the role of biotic interactions as factors that need to be understood thoroughly […]” (Soberón et al., 2009)

What is the role of biotic interactions?

Describe and measure the spatial-temporal responses of the phytoplankton community

with the occurrence of a harmful algae.

Aim

Global warming

Eutrophication

Community

Harmful species

Interaction Global Change

Aim

E1

E2

E

Niche concept

(Jackson and Overpeck, 2000)

E1

E2

E

Nf

Niche concept


E1

E2

E

Nf

Np

Niche concept


E1

E2

E NR

Nf

Np

Niche concept


E1

E2

E NR

Nf

Np

B

Niche concept


Subniche concept

Karasiewicz, S., Dolédec, S., Lefebvre, S., (2017). Within outlying mean indexes: Refining the OMI analysis for the realized niche decomposition. PeerJ.

E K

Subniche concept

E1

E2


E1

E2

E K

NR

Subniche concept


E1

E2

E

NR

K

Sp

Subniche concept


E1

E2

E K

SR

NR

Sp

Subniche concept


E1

E2

E K

SR

SB

NR

Sp

Subniche concept

Application

Phaeocystis spp.

+ Salinity (Borkman et al., 2016)

Appearance of Phaeocystis spp.

+N:P

- Si

+ Light

+ N:Si

References

(Riegman & Van Boekel,1996)

(Cadée and Hegeman, 1986)

(Peperzak 1993)

(Lancelot et al., 1987; Lancelot, 1990)

Phaeocystis spp.

Biomass

Winter Spring Summer Autunm Winter Spring Summer

Diatoms Phaeocystis

(Breton et al., 2006)

Phaeocystis spp.

Aim

Global warming

Eutrophication

Phaeocystis spp.

Global Change

Diatom Community

Interaction

Combination of REPHY (IFREMER) and SRN data (Lefebvre et al, 2011)

17 years (1998 to 2014)

26 diatoms species and Phaeocystis spp.

8 environmental variables

269 sampling dates

Data set

Calculates the overall species’ niche position and breadth of a community within an environmental space

G

OMI2

OMI1

OMI analysis (NR)

(Dolédec et al., 2000)

Calculates the sub- environmental space of HAB and non-HAB conditions

G

OMI2

OMI1

WitOMI index (SR)

(Karasiewicz et al., 2017)

G

OMI2

OMI1

G

OMI2

OMI1

WitOMI index (SR)


G

OMI2

OMI1

Calculates the sub- environmental space of HAB and non-HAB conditions

G

OMI2

OMI1


G

OMI2

OMI1

K1

WitOMI index (SR)

G

OMI2

OMI1


G

OMI2

OMI1

K1

Calculates the species’ subniche dynamics within the realized niche

NR

WitOMI index (SR)


G

OMI2

OMI1 NR

WitOMI index (SR)


G

OMI2

OMI1 NR

Sp

WitOMI index (SR)


G

OMI2

OMI1 NR

Sp

SR

WitOMI index (SR)


G

OMI2

OMI1 NR

Sp

SR SB

WitOMI index (SR)

G

OMI2

OMI1


G

OMI2

OMI1

K1

Can help determines a subcommunity

WitOMI index (SR)

ρ

Bray-Curtis

Bray-Curtis

Sp

eci

es

Samples

Correlation between a

species and the subcommunity

Species

Sam

ple

s

(Clarke et al., 2001)

Bv-Step analysis

Gives us the assemblage of species characterising the sub community

Environment trajectory

G

OMI2

OMI1

K1

Succession in realized subniche under each sub environmental condition

Summary 1. The abiotic effect on each species

(SP)

2. Subniche position and breadth for each species (SR)

3. Biotic contraint on SR (SB)

4. A characteristic subcommunity

5. A sub-environmental trajectory

6. Succession of species

OMI2 13%

OMI1 74,2%

Salinity

PAR

Temperature

Silicate

Nitrite + Nitrate

Turbidity

Phosphate

Ammonia

OMI analysis

OMI2 13%

OMI1 74,2%

Salinity

PAR

Temperature

Silicate

Nitrite + Nitrate

Turbidity

Phosphate

Ammonia

Nutrient

Sal

init

y Te

mp

eratu

re +

P

AR

OMI analysis

OMI1 74,2%

OMI2 13%

1

2 Phae

Led

Gus

Ske Thn

Thg

Dit

Pss

OMI analysis

E

Niche position

Niche position

OMI1 74,2%

OMI2 13%

1

2 Phae

Led

Gus

Ske Thn

Thg

Dit

Pss

Leptocylindrus danicus

Thalassionema nitzschioides

OMI analysis

Skeletonema spp

Thalassiosira gravida Pseudo-nitzschia

seriata complex

OMI1 74,2%

OMI2 13%

E

NR

OMI analysis

niche position

niche breadth NR

Phae

OMI1 74,2%

OMI2 13%

Low Phaeocystis abundance

E

NR

K SR

WitOMI index

Subniche position

Subniche breadth SR

OMI1 74,2%

OMI2 13%


E

NR

K

Sp

WitOMI index

Subniche position

Subniche breadth SR

OMI1 74,2%

OMI2 13%


E

NR

K SR

Sp

WitOMI index

Subniche position

Subniche breadth SR

OMI1 74,2%

OMI2 13%

E

NR

K SR

Sp

81% SB Low Phaeocystis abundance

WitOMI index

Subniche position

Subniche breadth SR

OMI1 74,2%

OMI2 13%

High Phaeocystis abundance

E

NR

K

Sp

SR

WitOMI index

Subniche position

Subniche breadth SR

OMI1 74,2%

OMI2 13%


25%

E

NR

K SR

Sp

SB

WitOMI index

Subniche position

Subniche breadth SR

OMI1 74,2%

OMI2 13%

NR

SR

E

SR

WitOMI index

OMI1 74,2%

Overall niche

OMI2 13%

E

NR

K

Sp

Low Phaeocystis abundance Phae

Succession

OMI1 74,2%

Overall niche

OMI2 13%

E

NR

K

Sp

Low Phaeocystis abundance Phae

Succession

J F

M

A M

J

J A

S N

D

O

OMI1 74,2%

Overall niche

OMI2 13%

E

NR

K

Sp


Ske

Thn Thg

Pss Par

Gud Phae

Gus

Succession

J F

M

A M

J

J A

S N

D

O

Overall niche

OMI1 74,2%

OMI2 13%


E

NR

K

Sp

J

F M A

M

J N

D J O

S

A

Ske Thn

Dit

Phae

Succession

Chaetoceros danicus Cha Ditylum brightwellii Dit Guinardia delicatula Gud Guinardia striata Gus Leptocylindrus danicus Led Nitzschia longissima Nit Paralia sulcata Par Pseudo-nitzschia seriata complex Pss Skeletonema spp. Ske Thalassionema nitzschioides Thn Thalassiosira gravida Thg Phaeocystis spp. Phae

Sub-community


Bv-Step analysis

8 species ρ = 0.97


Bv-Step analysis

8 species ρ = 0.97

10 species ρ = 0.96


Bv-Step analysis

6 common species

8 species ρ = 0.97

10 species ρ = 0.96

Discussion

Jan Mar Sep May Nov Jul

300

500

400

200

100

0

Me

an P

ha

eocy

stis

ab

un

dan

ce (

cell

/L)



Discussion

Discussion


300

500

400

200

100

0

Me

an P

ha

eocy

stis

ab

un

dan

ce (

cell

/L)



Feb - Jun

Discussion


300

500

400

200

100

0

Me

an P

ha

eocy

stis

ab

un

dan

ce (

cell

/L)



Mar - Jul

Feb - Jun

Appearance of Phaeocystis

+ Salinity

+N:P

- Si

+ Light

+ N:Si

Discussion

DIN

:PO

4

DIN

:SiO

H


SiO

H (

µm

ol/

L)

50

150

100

0

5

15

10

0

40

120

80

0 P

AR

(10

3 .W

.m²)

Turb

idit

y (N

TU

)

Jan Mar Sep May Nov Jul S

alin

ity

DIN

:PO

4

DIN

:SiO

H


SiO

H (

µm

ol/

L)

50

150

100

0

5

15

10

0

40

120

80

0


+ Salinity

+N:P

- Si

+ Light

+ N:Si

Discussion

PA

R (

103 .

W.m

²)

Tu

rbid

ity

(NT

U)


Sal

init

y

High

Low

+ Salinity


+N:P

- Si

+ Light

+ N:Si

Discussion

DIN

:SiO

H


SiO

H (

µm

ol/

L)

50

150

100

0

5

15

10

0

40

120

80

0 Tu

rbid

ity

(NT

U)


Sal

init

y

DIN

:PO

4

PA

R (

103 .

W.m

²)

High

Low


+ Salinity

+N:P

- Si

+ Light

+ N:Si

Discussion

DIN

:SiO

H


SiO

H (

µm

ol/

L)

50

150

100

0

5

15

10

0

40

120

80

0 Tu

rbid

ity

(NT

U)


Sal

init

y

DIN

:PO

4

PA

R (

103 .

W.m

²)

High

Low

Discussion

WitOMI able to investigate all hypothesis at once

Discussion

OMI1 74,2%

OMI2 13%

E

NR

K SR

Sp

81% SB Low Phaeocystis spp. abundance

Discussion

Subniche position

Subniche breadth SR

OMI1 74,2%

OMI2 13%

E

K

Sp

Phae

Discussion

K

Subniche position


Skeletonema spp.

Thalassiosira gravida

Pseudo-nitzschia seriata complex

OMI1 74,2%

OMI2 13%

E Sp

Discussion

K

Phae


Subniche position

Skeletonema spp.



OMI1 74,2%

OMI2 13%

E

K

Sp

Discussion

K

Phae

Subniche position


Skeletonema spp.





+N:P

- Si

+ Light

+ N:Si

References



(Peperzak 1993)


Discussion




+N:P

- Si

+ Light

+ N:Si

References



(Peperzak 1993)

Discussion

DIATOM COMPETITION (Karasiewicz et al., 2018)

Phaeocystis spp. realized niches will mostly depend on the nutrient concentration and ratios (Winter nutrient stock)

The preceding diatoms can over compete Phaeocystis spp and contract its realized subniche under nutrient rich conditions

Conclusion

For the post-doc Only one site Temporal study

For the post-doc Spatial-temporal study 1998-2016 All sites of occurence

For the post-doc

Check the data for exceptional value and/or jumps

For the post-doc

Check the data for exceptional value and/or jumps

(Rapport Aquaref, Soudant et al. 2015)

For the post-doc

Check the data for exceptional value and/or jumps Use smooth data or not?

(Rapport Aquaref, Soudant et al. 2015)

For the post-doc

Local Harmful species in a regional context

Alexandrium minutum Rade de Brest

Lepidodinum chlorophorum Baie de Vilaine, Baie de Bourgneuf

For the post-doc

Hypothesis on Alexandrium minutum occurrence: • >15°C • Strong tides • …

Hypothesis on Lepidodinum chlorophorum occurrence: • Strong river outflow • Low mixing • …

Test the crurent knowledge for each species

OMI1 74,2%

OMI2 13%

E

NR

K SR

Sp

For the post-doc

Reduce spectulation on species competition by calculating overlap (Schoener ,1970)

OMI1 74,2%

OMI2 13%

E

NR

K SR

Sp

81%

SB

For the post-doc

Reduce spectulation on species competition by calculating overlap (Schoener ,1970) Only on SB

For the post-doc

Correlation of HAB with oysters recrutment, growth, reproduction…?

Use the RESCO-REMORA and Velyger data Stéphane Pouvreau

Problematic

“In summer 2012 […] a major PSP contamination event led to the prohibition of shellfish harvesting.” (Chapelle et al., 2015)

What is the impact of HAB on aquaculture?

For the post-doc

Use data created from North-Atlantic POLCOMS-ERSEM model (until 2099) Martin Huret

Butenschon et al. 2016

For the post-doc

Use data created from North-Atlantic POLCOMS-ERSEM model (until 2099) Martin Huret

To create an a posteriori environmental trajectory to visualize how future condition will proceed through the species niches

2030 2040

2050

2060

2070

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