Diversity and Distribution of Marine Microbial Eukaryotes and Ecological Roles of Picoprasinophytes in Arctic Seas

Micro / pico-planktonic eukaryotes prevalent in the high-latitude waters in the euphotic exceptionally rich diversity, is miniature the basis of the food chain, occupies a very important position in the marine ecosystem. By the impact of global change Arctic coastal waters, such groups on ecosystems important. High-latitude coastal waters the micro zooplankton eukaryotes (≤ 50μm) gradient denaturing polyacrylamide gel electrophoresis (DGGE) differences in species composition and spatial and temporal distribution of the technical analysis of such groups, while the design of specific molecular probe, comprehensive assessment of pico-planktonic eukaryotes (≤ 5μm) dominant population abundance and biomass. In addition, China's third Arctic expedition samples of the waters of the Arctic Ocean Center Building SSU rRNA gene library, study miniature eukaryotic diversity of the central Arctic Ocean waters. And use of fluorescence in situ hybridization method (FISH) (≤ 5 μm) and flow cytometry count (FCM) (≤ 3μm) comprehensive assessment of pico-planktonic eukaryotes, in particular the pico-blue green algae ecology in the waters of the Arctic Ocean Center position . The main findings are as follows: 1. Using DGGE technology, analysis of the 2008 and the summer of 2009 Bay (N78 ° 59.29 'E 11 ° 39.60') spatial distribution characteristics of the eukaryotic community structure of micro-zooplankton. DGGE profiles, Wang Wan has a wealth of micro-planktonic eukaryotic diversity and significant spatial differences, differences in community structure of the outer bay and inner Bay, different stations have different micro-eukaryotic diversity. Canonical correspondence analysis (CCA analysis), temperature and salinity is a major environmental factors affect the micro-eukaryotic community structure in Kings Bay. DGGE sequencing results, the 2009 K3 stations eukaryotic groups have Syndiniales, Chamaeleomyces granulomatis, Calanus sinicus and Chrysophyceae sp. Bay, inside and outside the community diversity significantly different possible reasons: Atlantic warm current along the coast in the region of high temperature and salinity of seawater summer glacier melt water injection temperature and salinity gradient Bay as well as winter sea ice coverage. This leads to the Bay water temperature, salinity, turbidity change quickly, ecological complex and changing environment, resulting in different biological diversity. Waters B80-20 m of the Arctic Ocean Center and B85-0 m seawater samples were building a database of the SSU rRNA clone. CNC Ⅲ 05 CNC Ⅲ 51 two SSU rRNA gene library. The analysis shows that and, CNC Ⅲ 05 has a rich biodiversity, containing a total of five taxa: alveolates stramenopiles metazoans, chlorophytes and telonema. CNC Ⅲ 51 library in addition to the above five, there picobiliphytes Choanoflagellida. The two gene libraries, the Micromonas pusilla related species is one of the most frequently detected clones. Clone library estimation curve analysis, species relative abundance found in this study through the the gene library's species richness may be underestimated. Marine environment samples metagenomic library construction and the pyrosequencing technology applications can help us to better understand the diversity of the waters. 3 with a laboratory pure culture of the two polar algae (Chlorella vulgaris, the Micromonas SP), to set a different hybridization conditions, including the enzyme treatment, the denaturant formamide concentration, hybridization temperature and time, probe concentration, etc., of the fluorescent The in situ hybridization technique was optimized. The optimal hybridization conditions: 1) 10 mg mL-of lysozyme at and 37 ℃ preprocessing for 30 min; 2) hybridization buffer formamide concentration was 40%; 3) of 20μ1 hybridization solution the probe concentration of 2 μm; 4) hybridization conditions for the the 47 ℃ hybridization 6 h. And FISH FCM and DAPI count shows that the number of cells before and after hybridization no significant differences, indicating a high degree of hybridization efficiency, optimization of the hybrid system can be applied to the quantitative analysis of the Arctic marine environment samples. 4. Third scientific expedition Arctic Ocean Center waters samples FISH results show higher abundance of pico-planktonic eukaryotes, 1.94 X 103-2.37X 104cells mL1 (average abundance of 7.13 X 103 cells mL-1) . Pico-blue green algae (picoprasinophytes) accounted for 25.45% -86.89% (average 44.37%), as one of the dominant groups. The FCM results show that the abundance of pico-eukaryotes 0.955 × 103-1.073X104cells mL-1. FISH count (≤ 5μm) and FCM count (lt; 3μm) results show similar changes in the abundance trend in pico-eukaryotes obtained samples from all stations, but FISH count display abundance slightly higher. FISH findings prove that the thick ice sheets of the pico-blue green algae Micromonas the main coastal waters in the Arctic Ocean Center to play a \Fluorescence in situ hybridization the 2008 Arctic King Cove 50m water layer slightly above planktonic eukaryotes monitoring. The results show that the abundance of pico-eukaryotes 0.821 X 103-23.38 X 103cells mL-1, 0.25 X 103-6.64 X 103cells mL-1 accounted for 11.63% of the pico-eukaryotes pico-green green algae abundance - 54.64%, with an average of 29.11%. Despite the summer Arctic Wang Wanhai domain by the impact of various water masses surrounding the rapid changes in environmental factors, pico-blue green algae is still a very important role in the coastal ecosystem.