Electronic supplementary material
Hydrobiologia
Light history-dependent respiration explains the hysteresis
in the daily ecosystem metabolism of seagrass
Matthew P. Adamsa, Angus J. P. Ferguson, Paul S. Maxwell, Brodie A. J. Lawson, Jimena
Samper-Villarreal, Katherine R. O’Brien
a
Email: m.adams5@uq.edu.au. Address: School of Chemical Engineering, The University of
Queensland, St Lucia QLD 4072, Australia
Online Resource 1. O2 concentration vs time measured in closed chambers at the shallow
(grey circles), intermediate (grey squares) and deep sites (grey triangles), and O2
concentration vs time measured in open water loggers approximately midway between the
shallow and intermediate sites (red circles), and approximately midway between the
intermediate and deep sites (blue circles).
Online Resource 2. Water temperature over the day, for the three depths in Swansea Shoals,
New South Wales, Australia.
Online Resource 3. Parameters of the three models investigated in this paper (temperaturedependent respiration, light history-dependent GPP and light history-dependent respiration),
and three properties of the daily respiration variability predicted by the light historydependent respiration model (<Rday>/<Rnight>, Rmin, Rmax).
Variable
Site
Shallow
Intermediate
Deep
GPPmax (mmol O2 m-2 d-1)
360
672
547
Ik (µmol photons m-2 s-1)
369
368
343
R (mmol O2 m-2 d-1)
147
241
141
5
5
5
27.2
26.2
25.2
6
6
6
207
141
94
GPPmax,0 (mmol O2 m-2 d-1)
437
872
1359
k GPPmax ((mmol O2 m-2 d-1) / (µmol
0.2
0.7
2.5
Ik,0 (µmol photons m-2 s-1)
406
851
769
k Ik (no units)
2.6
2.5
8.1
R (mmol O2 m-2 d-1)
160
235
152
Model of temperature-dependent
respiration:
Temperature sensitivity of respiration Q10
(no units)
Reference temperature T0 (C)
Parameters common to both light history
models:
Light history timescale τ (h)
Light history at midnight Ihist,0 (µmol
photons m 2 s-1)
Model of light history-dependent GPP:
photons m-2 s-1))
Model of light history-dependent
respiration:
GPPmax (mmol O2 m-2 d-1)
510
785
681
-2 -1
468
340
291
-1
R0 (mmol O2 m d )
136
433
135
kR ((mmol O2 m-2 d-1)/(µmol
photons m-2 s-1))
0.6
1.0
1.5
Ratio of mean daytime to nighttime
respiration <Rday>/<Rnight>
1.9
1.7
2.1
Minimum instantaneous respiration value
Rmin (mmol O2 m-2 d-1)
44
114
41
Maximum instantaneous respiration value
Rmax (mmol O2 m-2 d-1)
393
492
417
Ik (µmol photons m s )
-2
Online Resource 4. O2 flux vs time (grey symbols), light vs time (black line), NEM vs time
predicted by our model of light history-dependent respiration (blue line), and the contribution
of respiration (-R) to NEM vs time predicted by our model of light history-dependent
respiration (green line), for (a) the shallow site, (b) the intermediate site, and (c) the deep site.
(a)
(b)
(c)