The following appendix accompanies the article
Aldehyde-induced insidious effects cannot be considered as a diatom
defence mechanism against copepods
Kevin J. Flynn1,*, Xabier Irigoien2
1
Institute of Environmental Sustainability, Swansea University, Swansea SA2 8PP, Wales, UK
2
AZTI-Tecnalia, Herrera Kaia, Portualdea z/g, 20110 Pasaia, Spain
*Email: [email protected]
Marine Ecology Progress Series 377:79–89 (2009)
Appendix 2. Additional figures
Fig. A1.
Comparisons between systems commencing with mixed
copepod populations, or with populations dominated by
young or old individuals (all with the same initial total copepod biomass).
Four scenarios are shown –
(a) Control, with non-toxic diatoms and non-noxious flagellates
(b) With PUA+ diatoms, which adversely affect the survival
of copepod nauplii (Egg + Naup stage in plots). Flagellates are non-noxious.
(c) With flagellates that become noxious when nutrient
stressed; these are avoided by both copepods and microzooplankton. Diatoms are non-toxic.
(d) With PUA+ diatoms and noxious flagellates
In each instance the left hand panel shows the biomass concentrations for diatoms, flagellates, microzooplankton (µZ),
total copepods, and voided particulate organic C (POC). The
right hand panel shows the breakdown of the total copepod
biomass (total shown in the corresponding left hand panel)
into eggs and non-feeding naupli, feeding naupli, copepodites and reproducing adults. Nutrients became limiting
for phytoplankton growth from Day 10 onwards for at least
the next 20 days.
Main paper Figs. 1 and 2 show the same results as Figs. A1a
and A1b (though in a different format); they are reproduced
here to aid comparison with the other model outputs.
Young copepods
1000
200
500
100
0
Copepod (mg C m–3 )
300
mg C m–3
400
400
1500
300
200
100
0
0
Old copepods
200
1000
100
500
0
0
0
10
20
30
Time (d)
40
50
60
Copepod (mg C m–3 )
mg C m–3
200
300
1500
150
100
50
0
0
10
20
30
40
Time (d)
Fig. A1a. Control showing impact of different copepod populations on system dynamics
50
60
2
Appendix 2 (continued)
Mixed copepods; PUA+ diatoms
200
100
500
0
Copepod (mg C m–3 )
mg C m–3
1000
200
300
Diatom
Flagellate
µZ
POC
Copepod
1500
10
20
30
40
50
150
100
50
0
0
0
Egg+Naup
Feeding Naup
Copepodite
Adult
60
0
10
20
30
40
50
60
20
30
40
50
60
30
40
50
60
Young copepods; PUA+ diatoms
1000
200
500
100
0
Copepod (mg C m–3 )
300
mg C m–3
400
400
1500
10
20
30
40
50
200
100
0
0
0
300
60
0
10
Old copepods; PUA+ diatoms
200
1000
100
500
0
0
0
10
20
30
Time (d)
40
50
60
Copepod (mg C m–3 )
mg C m–3
200
300
1500
150
100
50
0
0
10
20
Time (d)
Fig. A1b. With PUA+ diatoms, there is no enhancement of diatom population growth, and evidence of the contrary. Copepod
production is displaced in time relative to Fig. A1a
3
Appendix 2 (continued)
Mixed copepods; noxious flagellate
mg C m–3
1500
150
300
Diatom
Flagellate
µZ
POC
Copepod
200
1000
100
500
0
Copepod (mg C m–3 )
2000
10
20
30
40
50
100
50
0
0
0
Egg+Naup
Feeding Naup
Copepodite
Adult
60
0
10
20
30
40
50
60
30
40
50
60
30
40
50
60
Young copepods; noxious flagellate
200
1000
100
500
0
Copepod (mg C m–3 )
1500
mg C m–3
150
300
2000
10
20
30
40
50
50
0
0
0
100
60
0
10
20
Old copepods; noxious flagellate
200
1000
100
500
0
0
0
10
20
30
Time (d)
40
50
60
Copepod (mg C m–3 )
1500
mg C m–3
150
300
2000
100
50
0
0
10
20
Time (d)
Fig. A1c. With flagellates that become noxious when nutrient stressed, flagellates rather than diatoms come to dominate
4
Appendix 2 (continued)
Mixed copepods; PUA+ diatom/noxious flagellate
mg C m–3
1500
150
300
Diatom
Flagellate
µZ
POC
Copepod
200
1000
100
500
0
Copepod (mg C m–3 )
2000
10
20
30
40
50
100
50
0
0
0
Egg+Naup
Feeding Naup
Copepodite
Adult
60
0
10
20
30
40
50
60
40
50
60
40
50
60
Young copepods; PUA+ diatom/noxious flagellate
2000
200
1000
100
500
0
Copepod (mg C m–3 )
1500
mg C m–3
150
300
10
20
30
40
50
50
0
0
0
100
60
0
10
20
30
Old copepods; PUA+ diatom/noxious flagellate
2000
200
1000
100
500
0
0
0
10
20
30
40
Time (d)
50
60
Copepod (mg C m–3 )
1500
mg C m–3
150
300
100
50
0
0
10
20
30
Time (d)
Fig. A1d. A combination of PUA+ and noxious flagellates shows the advantage in immediately affecting the predator effort
Appendix 2 (continued)
Fig. A2.
Comparisons between systems commencing with mixed
copepod populations.
(e) With no microzooplankton (only copepod predators) present
(f) With elevated nutrients (eutrophic) such that phytoplankton did not exhaust nutrients and with no microzooplankton (only copepod predators) present.
(g) With only diatoms (no flagellates) present
Seven scenarios are shown –
(a) Control, with non-toxic diatoms and non-noxious flagellates – these are the same as in Fig. A1a for the mixed
copepod systems
(b) With higher mixing rates (0.02 d–1 rather than 0.01 d–1)
(c) With a lower (quarter control) initial phytoplankton biomass
(d) With elevated nutrients (eutrophic) such that phytoplankton did not exhaust nutrients.
In each instance the left hand panel shows the biomass concentrations for diatoms, flagellates, microzooplankton (µZ),
total copepods, and particulate organic C (POC). The right
hand panel shows the breakdown of the total copepod biomass (total shown in the corresponding left hand panel) into
eggs and non-feeding naupli, feeding naupli, copepodites
and reproducing adults.
Control
150
300
200
1000
100
500
0
Copepod (mg C m–3 )
mg C m–3
1500
10
20
30
40
50
50
0
0
0
100
60
0
10
20
30
40
50
60
50
60
PUA+ diatoms
200
100
500
0
0
0
10
20
30
Time (d)
40
50
60
Copepod (mg C m–3 )
mg C m–3
1000
200
300
Diatom
Flagellate
µZ
POC
Copepod
1500
Egg+Naup
Feeding Naup
Copepodite
Adult
150
100
50
0
0
10
20
30
40
Time (d)
Fig. A2a. Baseline (control) simulations for the following graphs (Fig. A1a–g) for systems started with a mixed copepod population with non-noxious flagellates, with or without PUA+ diatoms. Being PUA+ does not enhance diatom population growth but
does temporally displace copepod production
6
Appendix 2 (continued)
Control; higher mixing
150
300
200
1000
100
500
0
Copepod (mg C m–3 )
mg C m–3
1500
10
20
30
40
50
50
0
0
0
100
60
0
10
20
30
40
50
60
50
60
PUA+ diatoms; higher mixing
Diatom
Flagellate
µZ
POC
Copepod
1000
200
100
500
0
0
0
10
20
30
Time (d)
40
50
60
Copepod (mg C m–3 )
mg C m–3
150
300
1500
Egg+Naup
Feeding Naup
Copepodite
Adult
100
50
0
0
10
20
30
40
Time (d)
Fig. A2b. As Fig. A2a, but with a higher mixing rate, removing plankton (but not larger copepods) and introducing more
nutrients. Being PUA+ does not enhance diatom population growth but temporally displaces copepod production
7
Appendix 2 (continued)
Control; lower algal start
300
300
200
1000
100
500
0
Copepod (mg C m–3 )
mg C m–3
1500
10
20
30
40
50
100
0
0
0
200
60
0
10
20
30
40
50
60
50
60
PUA+ diatoms; lower algal start
Diatom
Flagellate
µZ
POC
Copepod
1000
200
100
500
0
0
0
10
20
30
Time (d)
40
50
60
Copepod (mg C m–3 )
mg C m–3
150
300
1500
Egg+Naup
Feeding Naup
Copepodite
Adult
100
50
0
0
10
20
30
40
Time (d)
Fig. A2c. As Fig. A2a, but with a lower initial algal biomass. This disturbs the temporal dynamics. Being PUA+ does not enhance
diatom population growth but temporally displaces copepod production
8
Appendix 2 (continued)
Control; eutrophic
3500
300
600
2500
400
2000
1500
200
1000
Copepod (mg C m–3 )
mg C m–3
3000
500
0
10
20
30
40
50
200
150
100
50
0
0
0
250
60
0
10
20
30
40
50
60
30
40
50
60
PUA+ diatoms; eutrophic
1500
300
200
1000
100
500
0
0
0
10
20
30
Time (d)
40
50
60
Copepod (mg C m–3 )
Diatom
Flagellate
µZ
POC
Copepod
2000
mg C m–3
150
400
2500
Egg+Naup
Feeding Naup
Copepodite
Adult
100
50
0
0
10
20
Time (d)
Fig. A2d. As Fig. A2a but due to higher nutrient loadings (100 µM rather than 10 µM each nitrate and silicate) phytoplankton
growth is more light than nutrient limited. The diatom dominates due to its faster growth rate. Being PUA+ does not enhance
diatom population growth but temporally displaces copepod production
9
Appendix 2 (continued)
Control; no µZ
150
300
200
1000
100
500
0
Copepod (mg C m–3 )
mg C m–3
1500
10
20
30
40
50
50
0
0
0
100
60
0
10
20
30
40
50
60
50
60
PUA+ diatoms; no µZ
Diatom
Flagellate
µZ
POC
Copepod
1000
200
100
500
0
0
0
10
20
30
Time (d)
40
50
60
Copepod (mg C m–3 )
mg C m–3
150
300
1500
Egg+Naup
Feeding Naup
Copepodite
Adult
100
50
0
0
10
20
30
40
Time (d)
Fig. A2e. As Fig. A2a, but with no microzooplankton. Because of the importance of microzooplankton in consuming phytoplankton, recycling nutrients and hence maintaining the nutrient status of the phytoplankton, the stoichiometric value of the phytoplankton as food becomes very poor and inadequate for the support of the copepods. Being PUA+ has no consequence for
the diatoms. Diatoms became increasingly silica limited, hence the success of flagellates
10
Appendix 2 (continued)
3000
5000
2500
4000
2000
3000
1500
2000
1000
1000
500
0
Copepod (mg C m–3 )
mg C m–3
Control; eutrophic no µZ
6000
10
20
30
40
50
750
500
250
0
0
0
1000
60
0
10
20
30
40
50
60
40
50
60
3000
5000
2500
Diatom
Flagellate
µZ
POC
Copepod
4000
3000
2000
1500
2000
1000
1000
500
0
0
0
10
20
30
Time (d)
40
50
60
Copepod (mg C m–3 )
mg C m–3
PUA+ diatoms; eutrophic no µZ
6000
Egg+Naup
Feeding Naup
Copepodite
Adult
1000
750
500
250
0
0
10
20
30
Time (d)
Fig. A2f. As Fig. A2a but phytoplankton growth is more light than nutrient limited. Compare with Fig. A2d,e. The diatom
dominates due to its faster growth rate. Being PUA+ does not enhance diatom population growth but temporally displaces
copepod production
11
Appendix 2 (continued)
Control
150
300
200
1000
100
500
0
Copepod (mg C m–3 )
mg C m–3
1500
10
20
30
40
50
50
0
0
0
100
60
0
10
20
30
40
50
60
50
60
PUA+ diatoms
200
100
500
0
0
0
10
20
30
Time (d)
40
50
60
Copepod (mg C m–3 )
mg C m–3
1000
200
300
Diatom
Flagellate
µZ
POC
Copepod
1500
Egg+Naup
Feeding Naup
Copepodite
Adult
150
100
50
0
0
10
20
30
40
Time (d)
Fig. A2g. As Fig. A2a, but with only diatoms present. There is little difference in comparison with Fig. A2a as the diatoms
dominate the algal biomass. Being PUA+ is of no benefit to the diatoms
12
Appendix 2 (continued)
Fig. A3.
These plots show the cumulative difference in diatom and
flagellate production (C-fixation) for test scenarios in comparison with the control situation where neither algal group
was noxious or toxic. The main paper Fig. 3 gives the Day 60
values for some of these comparisons (those in Fig. A3a);
here a more comprehensive comparison is made over the
period of each simulation.
(a) Differences within the main scenarios, with different
copepod age structures; main simulations shown in
Fig. A1.
(b) Differences within the additional scenarios, commencing
with a mixed copepod age structure; main simulations
shown in Fig. A2.
Diatom
Flagellate
600
% difference from control
10
% difference from control
Two pairs of plots are given.
0
–10
–20
–30
–40
–50
500
400
300
200
100
0
–100
0
10
20
30
40
50
60
0
10
20
Time (d)
30
40
50
60
Time (d)
nox flag with mix
PUA+ diat & nox flag with old
PUA+ diat with mix
nox flag with young
PUA+ diat & nox flag with mix
PUA+ diat with young
nox flag with old
PUA+ diat & nox flag with young
PUA+ diat with old
Fig. A3a. Differences between outputs from the main scenarios (Fig. A1), containing initial copepod populations that were either
mixed (mix), old or young in composition. The comparison data were from simulations in which the flagellates were non-noxious,
and the diatoms were not PUA+. In all instances being PUA+ was disadvantageous to the diatoms (negative differences). In contrast, becoming noxious during nutrient stress was clearly advantageous to the flagellates (large positive differences for noxious
flagellate configurations)
Diatom
Flagellate
250
% difference from control
% difference from control
10
0
–10
–20
–30
–40
–50
200
150
100
50
0
–50
0
10
20
30
Time (d)
40
50
60
0
10
20
30
40
50
60
Time (d)
Double mixing rate
No µZ
Lower algal start
Eutrophic & no µZ
Eutrophic
No flagellates
Fig. A3b. Differences between outputs from the additional scenarios (Fig. A2), containing initial copepod populations that were
mixed in composition. The comparison data were from simulations in which the flagellates were non-noxious, and the diatoms
were not PUA+. The different scenarios were a doubling in mixing rate (cf. Fig. A2b), a lower algal biomass start (cf. Fig. A2c),
eutrophic conditions (cf. Fig. A2d), no microzooplankton (µZ; cf. Fig. A2e), eutrophic & no µZ (cf. Fig. A2f), and no flagellates (cf.
Fig. A2g). In most instances being PUA+ was disadvantageous to the diatoms (negative differences); positive differences, where
they occurred, were small. In the eutrophic & no µZ scenario, the presence of PUA+ diatoms was more advantageous to the
flagellates than to the diatoms