Supplementary Material
Impact of biodiversity-climate futures on primary production
and metabolism in a model benthic estuarine system
Natalie Hicks*1,2, Mark T. Bulling2,3, Martin Solan2, Dave Raffaelli3, Piran C. L.
White3 and David M. Paterson1
1
Sediment Ecology Research Group, Scottish Oceans Institute , University of St
Andrews, East Sands, St. Andrews, Fife, KY16 8LB, United Kingdom
2
Oceanlab, University of Aberdeen, Main Street, Newburgh, Aberdeenshire, AB41
6AA, United Kingdom
3
Environment Department, University of York, Heslington, York YO10 5DD, United
Kingdom
*Correspondence author: Tel: + 44 1224 274401; Fax: + 44 1224 274402;
email: [email protected]
1
Figure S1: Set up of environmental chambers
Mesocosms were placed in an environmental chamber (VC 4100, Vötsch
Industrietechnik) which maintained a constant temperature environment (± 0.1 ˚C). The
atmosphere within the chamber was maintained (± 30 ppm) using a CO2 monitor and
controller linked to the gas regulator. Regulation of atmospheric CO2 was achieved
using an infra red gas analyser (ADC, LCA3) and the CO2 rich air was bubbled into
each individual mesocosm. This follows the experimental set up of Bulling et al. 2010.
2
Figure S2: Experimental design and treatments
The experiment was run during the late spring and early summer months of 2008, with
each successive temperature treatment applied at appropriate times (sequence listed
below, upper panel) to match the ambient seasonal water temperature at the study site
(see below, lower panel).
Chamber 1
BLOCK 1
BLOCK 2
BLOCK 3
BLOCK 4
BLOCK 5
Chamber 2
Temp °C CO2 ppmv Temp °C CO2 ppmv
6
370
6
600
6
1000
12
370
12
600
12
1000
18
370
18
600
18
1000
Mean water temperature in
study site (°C)
20
BLOCK 5
BLOCK 4
15
BLOCK 3
10
BLOCK 2
5
BLOCK 1
May
Spring
June
July
Summer
Time of year
3
Figure S3: Macrofaunal Species Richness and Composition
For each experimental run there were three replicates of eight treatments (i.e. n = 24
mesocosms per chamber, depicted below). The controls contained only MPB with no
macrofauna.
4
Figure S4: Annual Variation of Water Temperature from Ythan Estuary
The maximum (solid line) and minimum (dotted line) daily water temperatures from
01/01/2005 to 11/11/2009 recorded in the Ythan estuary, Newburgh, Aberdeenshire
25
Temperature (ºC)
20
15
10
5
01/10/09
01/07/09
01/04/09
01/01/09
01/10/08
01/07/08
01/04/08
01/01/08
01/10/07
01/07/07
01/04/07
01/01/07
01/10/06
01/07/06
01/04/06
01/01/06
01/10/05
01/07/05
01/04/05
-5
01/01/05
0
Date of Temperature Reading (dd/mm/yy)
5
Figure S5: Boxplots of Raw Data
600
400
200
MPB Biomass Fo
15
800
1000
Boxplot showing the raw data for mean MPB biomass at 6°C (red), 12°C (green) and
18°C (blue) for each CO2 concentration
370.6
600.6
1000.6
370.12
600.12 1000.12 370.18
600.18 1000.18
CO2 concentration.Temperature (ppm.°C)
6
Figure S6a: Bootstrapped models with confidence intervals
Confidence intervals (the error bars) around model predictions were estimated using a
bootstrapping methodology (Efron & Tibshirani, 1993). Model residuals were
randomly reordered to create an adjusted dataset and the statistical model parameters
were recalculated using this adjusted dataset. Model predictions were made for every
possible combination of independent variable factor levels. This whole process was
repeated 1000 times, to allow generation of bootstrapped distributions around the
original model predictions. Bootstrapped models of MPB biomass with increasing
Species Richness at 6°C (left column), 12°C (middle column) and 18°C (right column)
for each CO2 concentration (370 ppmv, top row; 600 ppmv, middle row; 1000 ppmv,
bottom row).
1000
1000
750
750
500
500
250
250
15
PredictedMPB
MPBbiomass
biomass(mg
(Fo L )1)
Predicted
00
1000
1000
750
750
500
500
250
250
00
1000
1000
750
750
500
500
250
250
2
HDHU
CVHU
1
HU
HDCV
HD
CV
0
3
HDCVHU
Species richness
identity
Species
Cntrl
3
HDCVHU
2
HDHU
CVHU
1
HU
HDCV
0
HD
CV
3
Cntrl
CVHU
HDCVHU
2
HDHU
1
HU
HDCV
0
HD
CV
Cntrl
00
7
Figure S6b: Boxplots of Raw Data for Species Richness
0
1
2
3
0
1
2
3
800
0
1
2
3
0
1
2
3
0
1
2
3
1
2
3
0
1
2
3
0
1
2
3
400
0
400
800
0
400
0
400
800
0
400
0
800
400
0
800
3
0
400
800
400
0
2
800
1
800
0
0
MPB Biomass (Fo-15)
0
400
800
Boxplots showing the raw data for MPB biomass with increasing Species Richness at
6°C (left column), 12°C (middle column) and 18°C (right column) for each CO2
concentration (370 ppmv, top row; 600 ppmv, middle row; 1000 ppmv, bottom row).
Species Richness
8
Figure S7a: Bootstrapped models with confidence intervals
Confidence intervals around model predictions were estimated using the bootstrapping
methodology as described in Fig. S3a. Bootstrapped models of MPB biomass for each
Species Identity at 6°C (left column), 12°C (middle column) and 18°C (right column)
for each CO2 concentration (370 ppmv, top row; 600 ppmv, middle row; 1000 ppmv,
bottom row).
1000
750
500
250
15
Predicted MPB biomass (Fo )
0
1000
750
500
250
0
1000
750
500
250
HDHU
CVHU
HU
HDCV
HD
CV
Cntrl
HDCVHU
Species identity
HDCVHU
HDHU
CVHU
HU
HDCV
HD
CV
Cntrl
CVHU
HDCVHU
HDHU
HU
HDCV
HD
CV
Cntrl
0
9
Figure S7b: Boxplots of Raw Data for Species Identity
0 1 2 3 4 5 6 7
800
0
800
400
400
800
0 1 2 3 4 5 6 7
0
400
800
0 1 2 3 4 5 6 7
0
0
400
800
0 1 2 3 4 5 6 7
0 1 2 3 4 5 6 7
0
400
800
0 1 2 3 4 5 6 7
0
0
400
800
0 1 2 3 4 5 6 7
MPB Biomass (Fo-15)
400
800
400
0
0
400
800
Boxplots showing the raw data for MPB biomass for each Species Identity at 6°C (left
column), 12°C (middle column) and 18°C (right column) for each CO2 concentration
(370 ppmv, top row; 600 ppmv, middle row; 1000 ppmv, bottom row).
0 1 2 3 4 5 6 7
0 1 2 3 4 5 6 7
Species Identity
10
Figure S8: Image of Sediment Resuspension
Four sample cores at the end of an experimental run illustrating the effect of activity by
Corophium volutator in resuspending sediment into the water column. The two on the
right contain C. volutator whilst the two on the left with clear water contain no C.
volutator.
11
Boxplots of raw data of pH measurements within mesocosms
8.2
8.0
7.8
pH measurement in mesocosm seawater
8.4
Boxplots showing the raw data of pH measured within the mesocosms for each of the
CO2 regimes across an increasing species richness gradient (top graph) and species
assemblage composition (bottom graph). The colour of the boxes indicates the CO2
regime: green (370 ppmv); orange (600 ppmv); red (1000 ppmv). This shows the pH
decreasing with increased atmospheric CO2.
0
1
2
3
0
1
2
3
0
1
2
3
8.2
8.0
CvHu
HdCvHu
HdHu
Hu
HdCv
Cv
Hd
Ctrl
CvHu
Macrofaunal Species Composition
HdCvHu
HdHu
Hu
HdCv
Cv
Hd
Ctrl
CvHu
HdCvHu
HdHu
Hu
HdCv
Cv
Hd
Ctrl
7.8
pH measurement in mesocosm seawater
8.4
Macrofaunal Species Richness
12
Structure of the minimal adequate models
a) Model for MPB biomass with carbon dioxide and temperature as independent
variables
MPB Biomass = f(CO2 conc. + Temperature
+ CO2 conc. × Temperature)
The model was a linear regression model with a gls extension (Temperature variancecovariate).
b) Model for MPB biomass with carbon dioxide, temperature and species richness
as independent variables
MPB Biomass = f(Species richness + CO2 conc. + Temperature
+ Species richness × CO2 conc.
+ Species richness × Temperature
+ CO2 conc. × Temperature
+ Species richness × CO2 conc. × Temperature)
The model was a linear regression model with a gls extension (Temperature and
Species richness variance-covariates).
c) Model for PO4-P concentrations with species richness as an independent
variable.
MPB Biomass = f(Species identity + CO2 conc. + Temperature
+ Species identity × CO2 conc.
+ Species identity × Temperature
+ CO2 conc. × Temperature
+ Species identity × CO2 conc. × Temperature)
The model was a linear regression model with a gls extension (Temperature and
Species identity variance-covariates).
13
References
Bulling MT, Hicks N, Murray LM, Solan M, Raffaelli D, White PCL, Paterson DM:
Marine biodiversity-ecosystem functions under uncertain environmental futures.
Philosophical Transactions of the Royal Society B 2010, 365, 2107-2116.
Efron B, Tibshirani RJ: An Introduction to the Bootstrap. Chapman and Hall, New
York, 1993.
END OF SUPPLEMENTARY MATERIAL
14