MAY 2016 ICES/PICES 6TH ZOOPLANKTON PRODUCTION …

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Nicole Aberle, Henriette Horn, Aleksandra Lewandowska, Ulrich Sommer MAY 2016 ICES/PICES 6TH ZOOPLANKTON PRODUCTION SYMPOSIUM BERGEN Microzooplankton in a changing environment: shifts in phenology and trophic relations

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Slide 1MAY 2016 ICES/PICES 6TH ZOOPLANKTON PRODUCTION SYMPOSIUM
BERGEN
trophic relations
temperat ure
enhanced UV radiation
sun
Sarmento et al.
2010;365:2137-2149
DFG Priority Programme AQUASHIFT:
Kiel Plankton Mesocosm Cluster
Experimental design
• Temperatures (ΔT): 0 and 6°C
• Additional manipulations:
• Treatments: 2 replicates each
Julian Days
Julian Days
Phytoplankton Microzooplankton Fish larvaeMesozooplankton
temperature changes than autotrophic ones
‘Metabolic Theory of Ecology’ (Brown et al. 2014)
Phenology shifts with warming
heterotrophs with warming
• Stronger top-down control of phytoplankton by MZP
• Alterations in energy transfer (enhanced dietary
competition between MZP and mesozooplankton)
WARMING
C u
m u
la ti
Qend= 75% threshold
Qstart= 25% threshold
Qmedian= 50% threshold
Aberle et al. Mar Biol 2012 → Earlier timing of MZP in the mesocosms
7
B io
g C
L -1
Julianischer Tag
ΔT=0 ΔT=2 ΔT=4 ΔT=6
40 60 80 100 12040 60 80 100 12040 60 80 100 120
10 -2
10 -1
10 0
10 1
10 2
10 3
Cil Phyto
8
6°C: 62%
Y A
x is
g C
l -1
Col 15
C
D
Y A
x is
P h
y to
p la
g C
l -1
Phenology shifts (2008)
biomass (size classes/community composition)
2. Warming at high copepod densities will lead to a strong
top-down control on MZP → MZP functions as a ‘trophic link’
3. Warming at low copepod densities will lead to an earlier
timing of MZP and a shortened temporal occurrence → MZP functions as a ‘trophic sink’
Test for the combined effects of warming and densities of
overwintering copepods on MZP biomass and phenology
Warming & overwintering copepod densities
11
Aberle et al. (MEPS 2015)→ MZP bloom intensity was highly affected by copepod density
→ Strong suppression of MZP (especially ciliates <30 µm) at elevated
temperatures
)
_A
_A
_A
_B
_B
_B
D 0°C: 1.5 cop L -1
_A
_A
_A
_B
_B
_B
D 6°C
r²= 0.67
M Z
P b
lo o
m in
te n
s it
y (µ
g C
l -1
temperat ure
enhanced UV radiation
sun
Phytoplanktonn
Microzooplankton
Mesozooplankton
Bacteria
Warming vs. OA: an indoor mesocosm study (BIOACID II 2012-2015)
• 12 mescocosms filled with Baltic
Sea plankton communities
max. 3000 ppm (high)
direct or indirect effects on the phenology, community
composition and carrying capacity of MZP?
Horn et al. (ICES J Mar Sci 2015)
Ciliate biomass (BIOACID II 2012)
cold warm
→ No effects of pCO2 on total ciliate biomass
Species composition (BIOACID II 2012)
Horn et al. (ICES J Mar Sci 2015)
C il
ia te
b io
m a
s s
→ Changes in MZP composition and succession
patterns with warming
Horn et al. (ICES J Mar Sci 2015)
C il
ia te
b io
m a
s s
• Warming affects MZP timing, growth, community
composition and succession
phytoplankton and MZP
• Stronger top-down control by copepods on MZP at high
temperature conditions
• High tolerance of MZP to changes in pCO2 (peak timing,
biomass and community composition remained
unaffected)
Kiel Mesocosm Cluster
for technical support
as phytoplankton consumers has
MZP and only 10% by mesozooplankton
Calbet et al. 2008
Warming will lead to:
heterotrophic processes with warming
3. Stronger top-down bloom control by MZP
4. Enhanced trophic overlap and dietary competition
between MZP and mesozooplankton
→ Strong suppression of the ciliate Lohmaniella oviformis
PZP community composition
)
)
Myrionecta rubra
Lohmaniella oviformis
Protoperidinium bipes
Protoperidinium pellucidum
Gyrodinium spp.
Gymnodinium spp.
Time course of small algae (yellow), diatoms (green), ciliates (red),
dinoflagellates (black) and copepods (blue)
6°C
0°C
500
1000
1500
a
500
1000
1500
b
500
1000
1500
c
500
1000
1500
d
500
1000
1500
e
500
1000
1500
f
→ With increasing Q10 of copepods a tighter coupling between PZP
and copepods occurs (strong top-down control of PZP) 24
Predator prey model (2008)
0.5
1
1.5
2
-1
0
1
0
0.5
1
1.5
2
0
0.5
1
-0.5
0
0.5
1
-1.5
-1
-0.5
• Mean biomass of small (CS) and large ciliates (CL) and
heterotrophic dinoflagellates (DINO)
• Black (ΔT=4°C, ΔT=6°C) and grey (ΔT=0°C, ΔT=2°C) linear regressions
(P<0.05)
Phytoplankton: green
MZP: orange
Copepods: grey areas 26
Aberle et al. (Mar Biol, 2012) → No top-down control of MZP at low temperatures + copepod
density
c o
p b
io m
a s
s (µ
g C
l -1
6°C: 1.5 cop L-1 6°C: 4 cop L-1
°C: 10 cop L-1
Day of the year
c o
p b
io m
a s
s (µ
g C
l -1
E
P Z
P b
io m
a s
)
Winder et al. Mar Biol 2012 → Advanced peak timing of PZP 27
Peak timing (2005-2009)
Winder et al.
Mar Biol 2012
Winder et al.
Mar Biol 2012
Peak magnitude (2005-2009)