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Home , Hacrobia, Syndiniales

Protist community structure in Atlantic Arctic through the year as revealed by high throughput sequencing

Elianne Egge, Daniel Vaulot, Aud Larsen, Gunnar Bratbak, Uwe John, Bente Edvardsen

University of Oslo, Department of Biosciences Pelagic food web

Size

Meso- phytoplankton zooplankton = unicellular Micro-

JT, UiO

Nano-

Pico- bacteria plankton Dissolved organic material Modified from Paasche 2005 The MicroPolar project “Processes and Players in Arctic Marine Pelagic Food Webs - Biogeochemistry, Environment and Climate Change”

Microbes in the Artic:

Who are they?

How are they distributed through the year and by depth?

What do they do?

How do they respond to environmental factors?

How do they interact with each other? Sampling campaigns in 2014

R/V Helmer Hanssen Sampling for metabarcoding

50L water per depth Size fractionation at 4 depths: 1, 15-25, 500, 1000 m Methods Metabarcoding data

• 155 samples

• Illumina HiSeq, 76 million reads (DNA sequences) after filtering

• Avg. 490.000 reads per sample

• Clustering at 98% similarity to operational taxonomic unites (OTUs)

• OTUs classified to against PR2 database

• Obtained 37 000 OTUs estimating species Who are the picoplankton? (0.4-3 µm) Proportional read abundance Richness (# OTUs of in total 7729) Picobilizoa Who are the plankton of 10-50µm?

Proportional read abundance Richness (# OTUs of in total 7879)

Bacillariophyta The most abundant genotypes (OTUs)

OTU Total # reads Supergroup Division Class Order Species OTU 1 288187 Alveolata Dinophyta Uncultured sp. OTU 2 261795 Stramenopiles Bacillariophyta Mediophyceae Chaetocerotales Chaetoceros gelidus OTU 3 194740 Alveolata Dinophyta Dinophyceae Dinophyceae sp. Uncultured sp. OTU 4 183788 Hacrobia Haptophyta Phaeocystales Phaeocystis pouchetii OTU 5 144912 Alveolata Dinophyta Dinophyceae Uncultured sp. OTU 6 127291 Stramenopiles Mediophyceae Thalassiosirales Uncultured sp. OTU 7 126854 Alveolata Dinophyta Dinophyceae Gymnodiniales Uncultured sp. OTU 8 114634 Alveolata Dinophyta Dinophyceae Dinophyceae sp. Uncultured sp. OTU 9 102582 Hacrobia Picobilizoa Picomonadea Picomonadida Uncultured sp. OTU 10 76110 Alveolata Dinophyta Dinophyceae Syndiniales Uncultured sp. OTU 11 71039 Alveolata Dinophyta Dinophyceae Syndiniales Uncultured sp. OTU 12 63158 Alveolata Dinophyta Dinophyceae Gymnodiniales Gyrodinium fusiforme OTU 13 62576 Alveolata Dinophyta Dinophyceae Gymnodiniales Uncultured sp. OTU 14 62299 Alveolata Dinophyta Dinophyceae Uncultured sp. OTU 15 58223 Hacrobia Picobilizoa Picomonadea Picomonadida Uncultured sp. OTU 16 57760 Alveolata Dinophyta Dinophyceae Syndiniales Uncultured sp. OTU 17 56452 Stramenopiles Stramenopiles MAST MAST-1 Uncultured sp. OTU 18 55403 Alveolata Dinophyta Dinophyceae Syndiniales Uncultured sp. OTU 19 48828 Hacrobia Picobilizoa Picomonadea Picomonadida Uncultured sp. OTU 20 46808 Mamiellophyceae Mamiellales Micromonas pusilla Most represented protist taxa

Micromonas Photo:W Eikrem Chaetoceros decipiens Chaetoceros gelidus Syndiniales

Thalassiosira Gymnodiniales Photo: L. Guillou Phaeocystis

In addition to Phaeocystis pouchetii, P. cordata, P. jahnii, P. globosa and P. cf. antarctica and several unknown species in this genus were detected. What are the abundant picoplankton Summer May + Aug surface (1-20m) May + Aug deep (200-1000m)

1. Micromonas pusilla 1. Dinophyceae, Syndiniales 2. Phaeocystis pouchetii 2. Phaeocystis_pouchetii 3. Bathycoccus prasinos 3. Dinophyceae, Syndiniales 4. Micromonas sp. 4. Dinophyceae, Syndiniales 5. Dinophyceae, Syndiniales 5. Dinophyceae, Syndiniales 6. Chaetoceros_gelidus 6. Dinophyceae, Syndiniales 7. Dinophyceae unclassified 7. Dinophyceae, Syndiniales 8. Dinophyceae unclassified 8. Dinophyceae, unclassified 9. Dinophyceae_unclassified 9. Dinophyceae, Syndiniales 10. Ciliophora, Sciurothamnion 10. Dinophyceae, Syndiniales 11. Ciliophora, Strombidiidae 11. Bathycoccus_prasinos 12. Ciliophora, Nassellarida 12. Dinophyceae, unclassified 13. Dinophyceae, Syndiniales 13. Micromonas sp.

Accumulated frequency Accumulated 14. Stramenopila, MAST sp. 15. , Picomonadidae sp.

Green: Phototrophs Red: Putative parasites

 Surface samples dominated by phototrophs, deep samples contain more heterotrophs and parasites What are the abundant picoplankton? Winter

Jan, Mar, Nov surface (1-20m) Jan, Mar, Nov deep (200-1000m)

Top 15 most abundant OTUs Dinophyceae, Syndiniales Picozoa, Picomonadidae Dinophyceae, Syndiniales Picozoa, Picomonadidae Dinophyceae, Syndiniales Dinophyceae, Syndiniales Dinophyceae, Syndiniales . Dinophyceae, Syndiniales Dinophyceae, Syndiniales Dinophyceae, Syndiniales Dinophyceae, Syndiniales Picozoa, Picomonadidae Dinophyceae, Syndiniales Stramenopila, MAST-1 Dinophyceae, Syndiniales Dinophyceae, Syndiniales Dinophyceae, Syndiniales Dinophyceae, Syndiniales Dinophyceae, Syndiniales Dinophyceae, Syndiniales Picozoa, Picomonadidae Dinophyceae, unclassified Dinophyceae, Syndiniales Amoebophrya_sp. Dinophyceae, Syndiniales Accumulated frequency Accumulated Dinophyceae, Syndiniales Dinophyceae, Syndiniales Dinophyceae, Syndiniales Picozoa, Picomonadidae Dinophyceae, unclassified

Green: Phototrophs Red: Putative parasites  Heterotrophs and putative parasites dominate completely in winter. In deep water parasites dominate. Richness through the season

Jan March May Aug Nov Stramenopiles incl. the diatoms Number of OTUs

Alveolates= and

 Lowest diversity is found in May in the surface during the spring bloom.  In the summer the diversity is higher in deep water than surface Taxonomic distribution of reads through the year 100% Proportion of of reads Proportion

0%

SW: Surface water AW: Atlantic water IW: Intermediate Arctic water ArW: Arctic water NH: Net haul Vertical and seasonal distribution of dominant taxa Jan March May Aug Nov Jan March May Aug Nov 25000 30000 OTU 1 Dinophyceae uncultured OTU 4 Phaeocystis pouchetii 25000 20000

20000 15000 15000 10000 10000 5000 5000 0 0 50000 50000 OTU 2 Chaetoceros gelidus (diatom) OTU 5 Syndiniales uncultured 40000 40000 (parasitic )

30000 30000

20000 20000

10000 10000 0 0

16000 OTU 3 Dinophyceae uncultured 14000 10000 OTU 21 Micromonas pusilla (Chlorophyta) 12000 9000 8000 10000 7000 8000 6000 5000 6000 4000 4000 3000 2000 2000 1000 0 0 OTU community composition

 t = surface (mostly 1m and 20m) Summer surface samples different from deep b = deep samples (below 200m) summer and all winter samples that seems rather similar Summary & conclusions

• The protist community composition differed significantly between the dark and light seasons and between surface water and below the photic zone.

• Dinoflagellates dominated both in OTU richness and relative read abundance in all samples except in May, when diatoms dominated.

• For the pico- and small nanoplankton the community composition was similar in deep summer samples and all winter samples, but differed to shallow summer samples, when phototrophs were dominant and the diversity was lower.

• During winter heterotrophic and parasitic dinoflagellates dominate the picoplankton community.

• Metabarcoding reveal a huge diversity and a large number of new records for the Arctic and taxa that may be unique to the Arctic.

• Most OTUs have best match with an uncultured environmental sequence and we need more DNA reference sequences for more precise identification. Acknowledgements Micropolar’s participants: AWI, Germany University of Bergen Uwe John Gunnar Bratbak Stephanie Westphal Aud Larsen Lise Øvreås CNRS/UMPC, Roscoff, France Bryan Wilson Ian Probert Jessica Ray Daniel Vaulot Jorun Egge Ruth-Anne Sandaa Hilde Stabell CNRS/UMPC, Banyuls sur Mer Hilde Armo Hervé Moureau

University of Oslo Elianne Dunthorn Egge Bente Edvardsen Wenche Eikrem Thank you for your attention! Rita Amundsen