Research On Diversity And Community Structure Of Picoplankton And Nanoplankton In The Arctic Ocean During Summer Seasons

Picoplankton and nanoplankton predominate in the marine concerning theirabundance, and they play an important role in material circulation and energy flow inthe marine ecosystem, and itself has rich diversity, and as the main contributor forprimary productivity in the marine. Global warming leads to Arctic temperature risesquickly in recent years, and in such a changing Arctic environment, the community anddiversity of pico-and nanoplankton should change dramatically. In order to understandvariation characteristics of pico-and nanoplankton in Arctic Ocean, this paper, byusing molecular biological technology such as denaturing gradient polyacrylamide gelelectrophoresis(DGGE) and building clone library, study the diversity, communitystructure, spatial distribution and the relation to environmental factors of pico-andnanoplankton in the Chukchi Sea, Bering Sea and Canada Basin of Arctic Ocean insummer2010. The main results as follows:The diversity of pico-and nanoplankton in Chukchi Sea R section of station1,5,7,9was assessed by using DGGE technology, the bacterioplankton diversity ismore than pico-and nanoplankton eukaryote in the Chukchi Sea, The Shannondiversity index of bacterioplankton was3.29, was highest from R5-48m, The Shannondiversity index of pico-and nanoplankton eukaryote was2.69, also highest fromR7-10m. Constructing clone libraries found the main groups of bacterioplanktonincluding Alphaproteobacteria, Betaproteobacteria and Bacteroidetes. Compared to thegroups of bacterioplankton at summer2008, the species is less. The groups of pico-and nanoplankton eukaryote including streptophyta, ascomycetes, basidiomycetes,amoebozoa and uncultured eukaryote, category is more but less quantity. A total of40%of the cloned sequences had sequence similarities that were <94%compared to previously reported sequences, indicating the presence of novel sequences in the ArcticOcean.The Bering Sea is a special geographical position in the Arctic Ocean, TheBering Sea and Bering strait are bridge that connected to the north Pacific Ocean andthe Arctic Ocean. Study on the diversity, community structure, spatial distribution andthe relation to environmental factors of pico-and nanoplankton in the Bering Sea Bsection7,13,15station at summer2010, found that Shannon diversity index ofbacterioplankton was the highest at B07-50m, for2.61; B07-3m is minimum, for1.99.Shannon diversity index of pico-and nanoplankton eukaryote is maximum in B07-10m, for2.48; B07-50m is Minimum, for1.79. Through cloning and sequencing, thebacterioplankton group is divided into four main phylogenetic groups of bacteria:Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria and Bacteroidetes. theproportion of Gammaproteobacteria is the largest, for53%, it is the dominantpopulation at bering sea; Bacteroides is second, for37%. The distribution ofbacterioplankton in the bering sea as follows: Gammaproteobacteria and Bacteroidetesexist in three sites, Alphaproteobacteria only exist in B07-50m、100m,Betaproteobacteria exist in three sites except B13-0m. There were significant positivecorrelation of Alphaproteobacteria distribution with salinity and Nitrate concentration.The groups of pico-and nanoplankton eukaryote including Alveolates, Stramenopiles,Chlorophyta, Haptophyceae and unknown groups. the proportion of Alveolates groupsis the largest, reach64%. Alveolates is the highest abundance of planktonic eukaryotesin the Bering Sea, it mainly include dinoflagellates and ciliates, dinoflagellates aredominant population. Micromonas pusilla was found in Chlorophyta, it may be as acontributor to the primary productivity in the Bering Sea.The Shannon diversity index of bacterioplankton was the highest at MS01-30m,at2.65; BN04-10m are the lowest, at2.11. the Shannon diversity index of pico-andnanoplankton eukaryote was is the highest at BN03-47m, for2.56; The lowest isMS03-30m, for2.03In the SR, BN and MS station of Canada Basin at summer. Bybuilding clone library, found that the groups of bacterioplankton is divided into fivecategories: Alphaproteobacteria, Gammaproteobacteria, Bacteroidetes, Firmicutes andCyanobacteria in Canada Basin. The proportion of Gammaproteobacteria is also the biggest. It is found Prochlorococcus in the Cyanobacteria, although the quantity is less,but contributes to the increase the primary productivity in Canada Basin. The groups ofpico-and nanoplankton eukaryote includes seven groups: Alveolates, Stramenopiles,Chlorophyta, Haptophyceae, Rhizaria, Platyhelminthes, Arthropoda and so on.Alveolates and Stramenopiles are the representative groups of pico-and nanoplanktoneukaryotes in Canada Basin, and Dinophyceae is the absolute advantage in Alveolates.Micromonas pusilla was also found in Chlorophyta. Moreover, the Phaeocystis in theHaptophyceae was a particular species in Canada Basin.