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-oxidation Oxidation + Rearrangement Suspended algal pool In situ production Sediments Fossil record Littoral production Zooplankton Faeces Digest Oxidation Saturation Rearrangement 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 O2O2

Comparison between water column and sediment samples 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)

Comparison between the sites Chlorophyll a and carotenoids

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

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

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

Earlier Himmerfjärden work Bianchi 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’

Comparison between the sites Ratios and Pheophytins

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