Upload
hilda-jackson
View
215
Download
0
Tags:
Embed Size (px)
Citation preview
Photosynthetic Capacity in Coral Photosynthetic Capacity in Coral Reef Systems: Applications for the Reef Systems: Applications for the
Underwater PAM FluorometerUnderwater PAM Fluorometer
Adrian Jones & William DennisonAdrian Jones & William Dennison
Thanks to the students of Coral Reef Biology & Geology (ID211) of Thanks to the students of Coral Reef Biology & Geology (ID211) of 1996 and Terrestrial & Marine Environmental Physiology (BT230) of 1996 and Terrestrial & Marine Environmental Physiology (BT230) of
19971997
Marine BotanyMarine BotanyThe University of QueenslandThe University of Queensland
AimsAims
• Generate photosynthesis versus irradiance (PI) Generate photosynthesis versus irradiance (PI) curves using Pulse Amplitude Modulated curves using Pulse Amplitude Modulated (PAM) fluorescence techniques (PAM) fluorescence techniques
• For a variety of marine macroalgae, determine For a variety of marine macroalgae, determine relationships between PI curves and various relationships between PI curves and various environmental factors environmental factors
• Use ecophysiological responses to infer light Use ecophysiological responses to infer light availability, desiccation stress and nutrient statusavailability, desiccation stress and nutrient status
PAM FluorometerPAM Fluorometer
Fibre OpticFibre OpticCableCable
Leaf ClipLeaf Clip
SubmersibleSubmersibleHousingHousing
• PAM generates saturating pulse of light which is used to PAM generates saturating pulse of light which is used to measure photosynthetic ratesmeasure photosynthetic rates
PAM FluorescencePAM Fluorescence(Pulse Amplitude Modulation)(Pulse Amplitude Modulation)
HeatHeat FluorescenceFluorescence
LightLight
PhotochemistryPhotochemistry
PQPQ PSIPSI
FFmaxmax -- FFinitialinitial ==
SaturatingSaturatingPulse from PAMPulse from PAM
PQPQPSIIPSII
PhotosyntheticPhotosyntheticYieldYield
PhotosyntheticPhotosyntheticYieldYield
Absorbed Absorbed LightLight
Electron Transport Rate Electron Transport Rate (ETR; µmol e(ETR; µmol e-- m m-2-2 s s-1-1))
xx ==
/ F / F maxmax(( ))
Rapid Light CurveRapid Light Curve
0
1000
2000
3000
4000
Inci
dent
Lig
ht
(µm
ol q
uant
a m
-2 s
-1)
Time (s)Time (s)1010 2020 3030 4040 5050 6060 80807070 909000
1 Second 1 Second Saturating PulseSaturating Pulse
10 Second 10 Second Actinic IrradianceActinic Irradiance
}
Rapid Light CurveRapid Light Curve
0
5
10
15
20
25
30
35
40
0 200 400 600 800 1000 1200 1400 1600
Photosynthetically Active Radiation (PAR)(µmol quanta m-2 s-1)
Ele
ctro
n T
rans
port
Rat
e (E
TR
)
(µm
ol e
- m-2 s
-1 )
PhotoinhibitionPhotoinhibition
Maximum ETR
Study SiteStudy Site
AustraliaAustraliaBrisbaneBrisbane
GreatGreat BarrierBarrier ReefReef
HeronHeronIslandIsland
HeronHeronIslandIsland
HeronHeronReefReef
WistariWistariChannelChannel
Heron IslandHeron IslandSouthern Reef FlatSouthern Reef Flat
Species ComparisonSpecies Comparison
0
50
100
0 500 1000 1500
Marine SpeciesMarine Species
ZooxanthallaeZooxanthallae
(Acropora)(Acropora)
0
50
100
0 500 1000 1500
ChlorodesmisChlorodesmis
PAR (µmol quanta m-2 s-1)
Terrestrial SpeciesTerrestrial Species
0
50
100
0 500 1000 1500
PAR (µmol quanta m-2 s-1)
ArgusiaArgusia
0
50
100
0 500 1000 1500
PisoniaPisonia
ET
R
(µm
ol e
- m-2 s
-1 )
ET
R
(µm
ol e
- m-2 s
-1 )
Experimental DesignExperimental Design(Reef Transect)(Reef Transect)
• Photosynthesis in Photosynthesis in ChlorodesmisChlorodesmis was measured along a was measured along a transect from 15m depth along the reef flat to the beachtransect from 15m depth along the reef flat to the beach
Reef FlatReef Flat ReefReefCrestCrest
BeachBeach
200m200m
GutterGutter 15m15m
20
30
40
50
60
70
80
0 20 40 60 80 100 120 140 160 180 200 220 2 5 10 15
Max
imu
m E
TR
(µ
mol
e- m
-2 s
-1)
Transect of Max ETR in Transect of Max ETR in ChlorodesmisChlorodesmis
BeachBeach
Reef Reef CrestCrestGutterGutter
Distance from Beach (m) Depth (m)
0
20
40
60
80
0 500 1000 1500PAR (µmol quanta mPAR (µmol quanta m-2-2 s s-1-1))
5m 10m 15m
ET
RE
TR
(µm
ol e
(µm
ol e
-- m m-2-2 s s
-1-1))
Experimental DesignExperimental Design(Desiccation)(Desiccation)
• Chlorodesmis Chlorodesmis collected from the reef flat and 15m collected from the reef flat and 15m was subjected to desiccation and fluorescence was monitored.
Reef FlatReef FlatReefReefCrestCrest
BeachBeach
200m200m
GutterGutter15m15m
0
10
20
30
40
50
0 20 40 60 80
Time (mins)
Max
imu
m E
TR
(µm
ol e
- m-2 s
-1)
Reef Flat 15m
Desiccation and RecoveryDesiccation and Recovery
DesiccationDesiccation RecoveryRecovery
Experimental DesignExperimental Design(Shading)(Shading)
• Several species of macroalgae and coral Several species of macroalgae and coral were shaded and the change in fluorescence were shaded and the change in fluorescence measured over 5 days.measured over 5 days.
50% PAR Shading50% PAR Shading
0
20
40
60
80
0 500 1000 1500 2000
Day 1 Day 2 Day 3 Day 4
ChlorodesmisChlorodesmis
ET
R (
µm
ol e
- m-2 s
-1 )
PAR (µmol quanta m-2 s-1)
0
60
120
180
0 500 1000 1500 2000
ChnoosporaChnoospora
Day 1 Day 2 Day 3 Day 4
ET
R (
µm
ol e
- m-2 s
-1 )
PAR (µmol quanta m-2 s-1)
0
20
40
60
80
100
0 200 400 600 800 1000 1200 1400PAR (µmol quanta m-2 s-1)
ET
R(µ
mol
e- m
-2 s
-1)
UV ScreenedControl
UV ShadingUV Shading
PadinaPadina
Experimental DesignExperimental Design(Fertilisation)(Fertilisation)
• Several species of macroalgae and coral were incubated Several species of macroalgae and coral were incubated for 10 days in flow-through aquaria with added for 10 days in flow-through aquaria with added nitrogen (88g mnitrogen (88g m-2-2) and phosphorus (22g m) and phosphorus (22g m-2-2) )
FertilisationsFertilisations
NutrientNutrientSufficiency StatusSufficiency Status
0
10
20
30
40
50
0 500 1000 1500 2000
FertilisedUnfertilised
PadinaPadina
ET
R (
µm
ol e
- m-2 s
-1 )
PAR (µmol quanta m-2 s-1)
0
5
10
15
20
25
30
0 200 400 600 800 1000 1200 1400
FertilisedUnfertilised
ChlorodesmisChlorodesmis
PAR (µmol quanta m-2 s-1)
0102030405060
0 500 1000 1500 2000
FertilisedUnfertilised
ColpomeniaColpomenia
ET
R (
µm
ol e
- m-2 s
-1 )
PAR (µmol quanta m-2 s-1)
FertilisationsFertilisations
0
20
40
60
80
100
0 500 1000 1500
FertilisedUnfertilised
AcroporaAcropora
PAR (µmol quanta m-2 s-1)
SummarySummary
• Rapid light curves in terrestrial and marine plants can be Rapid light curves in terrestrial and marine plants can be used to assess a variety of ecophysiological responsesused to assess a variety of ecophysiological responses
• Ability to generate Ability to generate in situ in situ PI curves rapidly, non PI curves rapidly, non destructively to determine relationships with various destructively to determine relationships with various environmental factorsenvironmental factors
• Ecophysiological responses to environmental gradients such Ecophysiological responses to environmental gradients such as desiccation, light, and depth can be ascertainedas desiccation, light, and depth can be ascertained
• PI responses can be used to infer a nutrient sufficiency status PI responses can be used to infer a nutrient sufficiency status