toxic blooms phenology and abiotic controls in a changing ......toxic blooms phenology and abiotic...
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Toxic blooms phenology and abiotic controls in a changing world. The case of Alexandrium minutum in Britany (French coast).
Annie Chapelle, Carles Guallar-Morillo, Cédric Bacher, Martin Plus, Marc Sourisseau, Guillaume Le Gland, Valérie le Guennec, Laure Guillou
• A. minutum blooms and toxicities, a 27 years survey on the French coast
• Environmental niche of A. minutum populations • Phenology of A. minutum blooms and its controls • Using 2 approachs, statistical and trait-based
modelling • In a changing world ?
A. minutum blooms and toxicities, a 27 years survey on the French coast
• First detection of A. minutum in 1988 (source Rephy) • Present on the English Channel, Atlantic and Mediterranean French coast
A. minutum blooms and toxicities, a 27 years survey on the French coast
High blooms leading to toxicity only in Breton Estuaries. Maximum 44 M cell L-1
(source Rephy and Final, Paralex, Daoulex projects).
• Penzé, Morlaix, Abers (since 88) • Rance (since 96) • Rade de Brest (since 2010)
A. minutum blooms and toxicities, a 27 years survey on the French coast
• Niche analysis Statistical studies : 1988 – 2014 •Phenology analysis 17 regions, 67 stations •Trait-based modelling Brest bay, 2012 - 2014
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Chlorophyll In situ, Satellite Temperature In situ, Satellite, Models
Salinity In situ, Models Turbidity In situ Oxygen In situ
Suspended Particulate Matter Satellite Nutrients (N, P, Si) In situ, Models
Irradiance Satellite Tide (coefficient and hight) In situ, Models
River flow In situ Atmospheric pressure In situ, Models
Wind (Direction, Speed) In situ, Models AMO, NAO Climate index
Environmental parameters Studied sites
Environmental niche of A. minutum populations
• ‘The ecological niche is the volume in the environmental space that permits a positive growth of the species’ (Hutchinson 1957)
• Potential niche versus realised niche
Principal Component Analysis (Trait-base modelling)
• Define environmental space
Principal Component Analysis
Environmental var. 1
Environmental var. 4
Environmental var. 2
Environmental var. 3
(Broennimann et al. 2012) Kernel density function
Environmental niche of A. minutum populations
• ‘The ecological niche is the volume in the environmental space that permits a positive growth of the species’ (Hutchinson 1957)
• Potential niche versus realised niche
(Dutkiewicz & Follows, 2009)
Traits Types of distributions Diatom or Dinoflagellate Random law (Binary reponse)
Size (1µm – 100µm) Random and uniform law
Optimal temperature (10°C – 20°C)
Random and uniform law
Maximum growth rate Eppley function ( dependence in Topt)
Minimum Quota in Nitrogen, Phosphate and Silicium
Allometric law (Trade off with size)
Maximum Quota in Nitrogen, Phosphate and Silicium
Allometric law (Trade off with size)
Maximum Uptake rate in Nitrogen, Phosphate and Silicium
Allometric law (Trade off with size and optimal temperature)
Saturation coefficient in Nitrogen, Phosphate and Silicium
Allometric law (Trade off with size)
Optimal irradiance Constant : 20 W.m-2
(Principal Component Analysis) Trait-base modelling • 50 species + A.minutum
1 25 50 75
Contour probability mass
Environmental niche of A. minutum populations
• Principal Component Analysis
Realised niche : Warm temperatures, high irradiance, low river flow Lower turbidity and higher salinities favourable
NAO and tides apparently no influence
Environmental variables Minimum Maximum
Salinity 3.20 38.10 psu
Temperature 4.40 25.90 °C
Turbidity 0.08 120.00 NTU
Sea Surface Irradiance 8.9 416.5 W · m-2
Tidal coefficient 38.6 103.9
North Atlantic Oscillation index -1.654 1.658
-0.06 -0.02 0.02 0.06
-0.0
6-0
.02
0.02
0.06
PC1 (31.3%)
PC
2 (1
7.7%
)
River flow
Salinity
Turbidity SSI
Temp.
Tidal coeff.
PC1 (34.5%)
PC2
(15.
6%)
PC3 = 14.1%
•NAO
n = 6798
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Environmental niche of A. minutum populations Trait-based numerical modelling
• A. minutum alone → Potential niche
Abun
danc
e (c
ell L
-1)
Abun
danc
e (c
ell L
-1)
A. minutum alone
A. minutum in competition
Potential niche : From May to October Realised niche : From May to August
• A. minutum in competition → Realised niche Model Data
A. minutum _____
Picoplancton _____
Nanoplancton _____
Microplancton _____
Environmental niche of A. minutum populations • Trait-based numerical modelling
Temperature control N, P control
Potential niche : Dilution, Temperature. Temperature treshold : 15°C Realised niche : Dilution, Temperature, Nutrients. Importance of competition for nutrients
T control
Bloom possible when : µ > d µ (T, I, Nut) d (tide, flow)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
dilution - growth
15°C
temperature
‘Phenology’ characterise the life cycle phases or activities of plants and animals in their temporal occurrence throughout the year, especially in relation to climate and weather’ (Lieth 1957, Vliet & de Groot 2004)
Define Phytoplankton bloom events
1 Max. abundance day 2 Max. abundance 3 Bloom start day 4 Bloom end day 5 Bloom length
Phenology of A. minutum and its controls
0 100 200 300
0e+0
02e
+06
Al
exan
driu
m m
inut
um
0 100 200 300
0e+0
02e
+06
1. Raw data
0 100 200 300
01
23
45
6
Lo
g 10 A
lexa
ndriu
m m
inut
um
Day of the year
2. Log10 transformation
6 Increase length 7 Decrease length 8 Steepness increase 9 Steepness decrease
Day of the year
Abun
danc
e
1,2
3 4
5 6 7
8 9 Day of the year
3. Fit Weibull function
(Rolinski et al. 2007)
0 1 2 3 4 5 6 7
1length_bloom
0 100 200 300
4yday_start6yday_end
0 100 200 300
1steepness_
-2 -1 0 1 2
Log10(Alexandrium minutum)
Days
Day of the year
Day-1
Maximum abundance
Steepness increase
Decrease duration
Increase duration
Maximum abundance day
Bloom duration
Bloom end day
Bloom start day
Steepness decrease
Phenology of A. minutum and its controls
Weibull application to data (52 year-station time series)
Phenology of A. minutum and its controls
Temperature at the start of the bloom control growth rate (+), bloom length (-), bloom increase length (-), bloom lenght decrease (-).
Irradiance and Salinity also correlated but less.
Stepwise regressions with environmental parameters
8 10 12 14 16 18
020
4060
8010
012
0
df_Phen$Temp_start
df_P
hen$
raw
_len
gth_
incr
ease
Blo
om le
ngth
incr
ease
(Day
s) Bloom length increase
Linear model R2 = 0.77
Start Temperature (°C) 0.0 0.1 0.2 0.3 0.4 0.5 0.6
0.0
0.2
0.4
0.6
0.8
1.0
fitted(model_glm)
mod
el_g
lm$m
odel
$"df
_Phe
n$ Steepness increase
Obs
erve
d
Predicted
Logistic model R2 = 0.72
Temperature Temperature
Irradiance Salinity (River flow?)
Factors
Phenology of A. minutum and its controls 3 years modelling, Brest bay
2012 2013
2014
R² = 0.8995
100110120130140150
60 80 100 120
Mod
el d
ata
(d)
In situ data (d)
Start of the bloom
2012 2013
2014
R² = 0.9086
200220240260280300
285 290 295 300 305 310M
odel
dat
a (d
)
In situ data (d)
End of the bloom
2014
2013
2012
R² = 0.5986
175180185190195200205
185 190 195 200 205
Mod
el D
ata
(d)
In situ Data (d)
Day of the maximum
2012
2013
2014
R² = 0.9751
0
500000
1000000
1500000
0 20000000 40000000 60000000Mod
el d
ata
(Cel
l/L)
In situ data (Cell/L)
Max value of abondance
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Abundance max : 2012 > 2014 > 2013 Day of the maximum: 2014 > 2012 >2013 Start of the bloom : 2014 > 2013 > 2012 End of the bloom : model ≠ data
0 1 2 3 4 5 6 7
1length_bloom
0 100 200 300
4yday_start6yday_end
0 100 200 300
1steepness_
-2 -1 0 1 2
Log10(Alexandrium minutum)
Days
Day of the year
Day-1
Maximum abundance
Steepness increase
Decrease duration
Increase duration
Maximum abundance day
Bloom duration
Bloom end day
Bloom start day
Steepness decrease
Phenology of A. minutum and its controls Weibull application to data (52 year-station time series) + 3 years modelling
___ 2012
___ 2013
___ 2014
2012 is a very exceptional bloom in term of amplitude in the Brest bay Blooms in Brest bay lasted more
Phenology of A. minutum and its controls
3 years modelling, Brest bay
Temperature controls the bloom initiation Nutrients (P) control the bloom amplitude
Temperature limitation Phosphorus limitation
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
+ +
-
Alexandrium minutum phenology and controls, in a changing world ? Perspectives
Bust : Parasitic control Boom : Abitoic control Lag
Guillou et al 2015
A. minutum
Temperature
Tides
River flow
Nutrients
Climatic changes
Human changes
+
+ +
-
-
Abiotic controls
Predation Parasitism
Intra/Inter specific
competition
Life cycle
-
Biotic controls
Alexandrium minutum phenology and abiotic controls, in a changing world ? Perspectives - Scenarios
A. minutum
Temperature
Tides
River flow
Nutrients
Climatic changes
Human changes
+
+ +
-
-
Abiotic controls Biotic controls
Predation Parasitism
Intra/Inter specific
competition
Life cycle
Abiotic controls : need scenarios climatic and human changes Biotic controls : our studies and collaborations
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