methods pigment analyses by hplc identification of pigments by –rt (retention time) –pda...
TRANSCRIPT
Methods• Pigment analyses by HPLC
• Identification of pigments by – RT (retention time)
– PDA (photodiode array)
– LC-MS (mass spec.)
Sediment Pigments as Biomarkers of Environmental Change
Summary of signature pigments useful as markers of algal groups in the sea
Flux and degradation of pigments
Hours-days
Weeks-months
Season-Year Millenia-Century
Half – life
Photo-oxidationOxidation +Rearrangement
Suspendedalgal pool
In situ production
Sediments
Fossil record
Littoralproduction
Zooplankton
Faeces
Digest
OxidationSaturationRearrangement
Saturation
Redrawn from Leavitt (1993)
Objectives of the pigment work
1. Plankton community structure response to long-term changes in anthropogenic disturbance
2. The effects of varying bottom water oxygen conditions
Mariager Fjord: Permanently anoxic at the bottom, silt fjord
Himmerfjärden: Experience temporary hypoxic/anoxic bottom water
Laajalahti: Possibility of temporary hypoxic conditions at the bottom
Ems-Dollard: Mudflat, exposed to air once a day
O2
Comparison between water column and sediment samples
AU
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
Minutes10.00 20.00 30.00 40.00
8.56
39.
655
11.1
2812
.270
12.8
9013
.716
14.2
8815
.416
16.1
8416
.796
17.3
8818
.531
19.0
48 20.0
7121
.475
22.5
9523
.692
28.0
8428
.446
29.1
8329
.555
30.4
0931
.296
32.8
5233
.878
36.1
1736
.698
37.0
94 37.4
2737
.890
38.4
25
AU
0.00
0.05
0.10
0.15
0.20
0.25
Minutes10.00 20.00 30.00 40.00
7.3
338.1
388.3
088.9
419.1
809.7
2610.0
6010.3
6410.5
2211.3
8611.7
3612.2
9612.8
2913.3
7513.7
6614.0
9914.8
4715.4
9515.8
1116.2
6816.6
7717.1
5317.3
9617.6
9618.2
06 18.6
9219.4
7219.9
6720.2
6620.7
2921.2
0221.8
6222.3
1922.4
9423.0
9823.7
7724.3
3724.6
6125.1
7925.5
0425.9
9226.8
1627.1
5627.3
3828.2
6128.5
6328.7
6129.4
4229.9
3030.3
44 30.7
5631.3
6231.8
7832.2
9632.5
2732.8
36 33.1
1933.6
9534.5
0834.9
3635.5
0536.1
3436.4
9536.9
4637.7
2338.5
7439.6
3640.3
7940.6
8141.5
3642.5
7144.5
63
Mariager Fjord (9-10cm)NASA surface water NW most station in grid, close to shore
Fucoxanthin and Chlorophyll a peaks dominate in both samples
(both chromatograms recorded at 438nm)
Total Carotenoids
mg/gC
0,0 0,5 1,0 1,5 2,0
Dep
th
0
10
20
30
40
50
60
Mariager FjordLaajalahtiEms-DollardHimmerfjärden
Comparison between the sitesChlorophyll a and carotenoids
Chlorophyll a
mg/gC
0,0 0,2 0,4 0,6 0,8 1,0 1,2 1,4 1,6 1,8
De
pth
0
10
20
30
40
50
60
Mariager Fjord LaajalahtiEms-DollardHimmerfjärden
Important carotenoids
µg pigment/g sediment
0 20 40 60 80
De
pth
(cm
)
0
10
20
30
40
FucoxanthinDinoxanthinDiadinoxanthinAlloxanthin Diatoxanthin Lutein Zeaxanthin
Mariager Fjord - Carotenoids/History
•A slight decrease with depth, but big variation•Individual carotenoids follow the general pattern from chl a and total carotenoids•Dominating carotenoids: Fucoxanthin and Diadino/Diatoxanthin = Diatoms
MF6 Chlorophyll a and total carotenoids
µg pigment/g sediment
0 50 100 150 200 250
Dep
th
0
10
20
30
40
Chlorophyll aTotal carotenoidsTotal pheophigments
Laajalahti - Carotenoids/History
•No distinct trend over time, but a distinct peak at 15-16cm depth (more samples)•Individual carotenoids follow the general pattern from chl a and total carotenoid•Dominating carotenoid: Diatoxanthin, Lutein and Alloxanthin•No Fucoxanthin probably because of degradation
Important Carotenoids
µg/g sediment
0,0 0,5 1,0 1,5 2,0 2,5
De
pth
0
10
20
30
40
Diadinoxanthin Alloxanthin Diatoxanthin Lutein Zeaxanthin Canthaxanthin
2000
1975
1900
1950
1990
LA-C Chlorophyll a and total carotenoids
µg pigment/g sediment
0 5 10 15 20
Dep
th (
cm)
0
10
20
30
40
Chlorophyll aTotal carotenoidsTotal pheopigments
R1 Chlorophyl a and carotenoids
µg pigment/g sediment
0 2 4 6 8 10
Dep
th (
cm)
0
10
20
30
40Chlorophyll aTotal carotenoidsTotal pheopigments
Important carotenoids
µg pigment/g sediment
0,0 0,2 0,4 0,6 0,8 1,0 1,2 1,4 1,6 1,8
De
pth
0
10
20
30
40
Fucoxanthin vs Depth Diadinoxanthin vs Depth Diatoxanthin vs Depth Lutein vs Depth Zeaxanthin vs Depth
Ems-Dollard - Carotenoids/History
•A clear decrease in all pigments down core•Individual carotenoids follow the general pattern from chl a and total carotenoid•Dominating carotenoid: Fucoxanthin in top, Diatoxanthin and others down core•Very low amount of pigments below 5 cm
Himmerfjärden - Carotenoids/History
•Only high concentrations in top sediment•Most individual carotenoids not securely identified!•High ratioes beteween degradation products and chlorophyll
H4-7 Chlorophyll a and carotenoid
µg/g sediment
0 5 10 15 20 25
Dep
th
0
20
40
60
80
100
120
Chlorophyll aTotal carotenoidsTotal pheopigments
Alloxanthin
µg/g sed
0,00 0,05 0,10 0,15 0,20
De
pth
0
20
40
60
80
100
120
Earlier Himmerfjärden workBianchi et al. (2002)
• Laminated cores from H5 (not H4 because of lack of lamination)
• Correlation between diatom biomass and down-core concentration of fucoxanthin and diatoxanthin (5 year average)
• No correlation between cyanobacteria and zeaxanthin (used in Baltic samples)
• 30 cm ~ 25 years, mean sedimentation rate 1.36 cm yr-1
• Lack of closer correlation:
- differential phytoplankton cell settlement
- sediment resuspension and sediment transport
- differential decay of specific biomarkers
• Conclusion: ‘indication that pigment biomarkers do reflect longer term bloom development in estuarine systems with anoxic, laminated sediments’
Ratio of pheopigments to chlorophylls (chl b,a)
ratio
0 2 4 6 8 10 12
Dep
th
0
10
20
30
40
50
60
Mariager FjordLaajalahtiEms-DollardHimmerfjärden
Comparison between the sitesRatios and Pheophytins
Pheophytins
mg/gC
0,0 0,2 0,4 0,6 0,8
Dep
th
0
10
20
30
40
50
60
Mariager FjordLaajalahtiEms-DollardHimmerfjärden
Preliminary conclusions•Big variation in total chl a and carotenoids pr gC between sites•Clearly highest values in Mariager Fjord and very low values in
Ems-Dollard estuary, variation in Laajalahti samples and a sharp decline in Himmerfjärden
•Samples from Mariager Fjord, Laajalahti and Himmerfjärden were influenced by a lot of chlorophyllous peaks, maybe a result of handling of wet samples (labile compounds)
•Carotenoids were often masked by co-eluting compounds (possibly chlorophyllous) and secure identification were difficult, often rely on RT especially in Himmerfjärden
•No bacteriomarkers found and hence no secure indicator of anoxia (possible use of inorganic markers e.g. sulphides, pyrite?)
•Use of Chl a degradation products as an indicator may be difficult since no clear trend between sites were found
•Compare with other proxies, dating essential