1. Picoplankton Community Structure subarctic (K2) v.s. subtropical (Aloha similar) ---------------------------------------------- Nianzhi (George) Jiao, Yao Zhang Xiamen University China

2. Investigation Sites Fig. 1 Sampling stations Chlorophyll a remote images (Aqua-MODIS) of August 2005 were employed as the backgrounds. NWPG: North Western Pacific; NEP: North Eastern Pacific; MNEP: Marginal sea of North Eastern Pacific.

3. Picoplankton discrimination by FCM ProchlorococcusSynechococcus PicoeukaryotesHeterotrophic bacteria

4. AAPB ( aerobic anoxygenic phototrophic bacteria ) TIREM Jiao et al., 2006, TIREM Jiao et al., 2006, Journal of Microbiological Methods

5. Paths of Photosynthesis Karl, 2002

6. Sunlight Phtosynthesis in Phytoplankton Phtosynthesis in AAPB C fixation ATP Save OC Ocean C cycling Re-budget ?? respiration consumption

7. Carbon cycling

8. TEM-Ultrathin sections SEM dc10-s dg26-y-1(2216) dc10-s db6-y-2(0.2) TEM-Negatively stained cells AAPB cells

10. Non-AAPB AAPB ciliatesMeso-zooplanktonflagellates ciliates flagellates Meso-zooplankton Cellular contribution to sinking flux in AAPB could also be higher than non-AAPB

11. Deployment 1 Deployment 2 Depth profiles of the abundance (upper) And biomass (lower) of picoplankton at K2.

12. Fig. 4 Depth profiles of picoplankton at K2 with false connection down to 200m. The data of 60-200m are adopted from Liu et al. 2002.

13. Picoplankton Carbon Biomass at K2 Fig. 5 Depth profiles of pico-sized autotrophic and heterotrophic carbon biomass at K2. The data of 60-200m (shaded) were from Liu et al. 2002.

14. Comparison between K2 and Aloha similars Fig. 1 Sampling stations Chlorophyll a remote images (Aqua-MODIS) of August 2005 were employed as the backgrounds. NWPG: North Western Pacific; NEP: North Eastern Pacific; MNEP: Marginal sea of North Eastern Pacific.

15. Pico- biomass K2 v.s. NWPG Fig. 6 Vertical distribution of pico-sized autotrophic and heterotrophic carbon biomass at K2 and NWPG1 Surface layer: Auto > hetero Auto < hetero Twilight zone: Auto hetero Gyre K2

16. Comparison along longitude Fig. 1 Sampling stations Chlorophyll a remote images (Aqua-MODIS) of August 2005 were employed as the backgrounds. NWPG: North Western Pacific; NEP: North Eastern Pacific; MNEP: Marginal sea of North Eastern Pacific.

17. NEP1, 2,3,4 Auto –fraction increased eastward Vertical distibution of pico-sized autotrophic and heterotrophic carbon biomass at NEP

18. Fig. 10 Variation of vertical profiles of pico-sized autotrophic and heterotrophic carbon biomass along longitude

19. NEP4 (1,2,3,4) K2 (1,2) in terms of Biomass flux and auto/hetero ratio; although composition are different Vertical distribution of pico- sized autotrophic and heterotrophic carbon biomass at NEP4 Depth profiles of pico-sized autotrophic and heterotrophic carbon biomass at K2

20. Two dimensional trends

21. Conclusions Picoeukaryoes and Synechococcus dominate carbon biomass of pico-autotrophs at K2 Prochlorococcus dominate carbon biomass of pico-autotrophs at low latitudes especially in the oligotrophic areas. AAPB are more abundant in entrophic waters than in oligotrphic waters picoplankton carbon flux maximum layer depth eutrophic waters: 50-75m oligotrophic waters: 100-150m Temperature and nutrients are two major controlling factors Variations along gradients: autotrophs >> heterotrophic bacteria Therefore whether or not a province is autotrophic or heterotrophic is determined primarily by autotrophs

22. Cheers! K2 Aloha