Study On Ultraplankton Diversity By The Use Of HPLC Pigments Analysis In The Three Gorges Reservior

The Three Gorges Reservoir is remarkable water conservancy project. Eco-environmentof the reservoir was inevitable impacted by its water storage. It is significant to study thedynamic of the reservoir ecological system and phytoplankton distribution.Ultraphytoplankton are major primary producers in all aquatic ecosystems. This study wascarried out to know the ultraphytoplankton community structure and spatio-temporal variationwith the main controlled environment factor.Characteristic photosynthetic pigment can indicate certain ultraphytoplankton, byCTEMTAX operation, ultraphytoplankton community composition can be gained based onpigment concentration. Methods of HPLC pigments analysis were optimized, includingpigments extraction conditions, chromatographic conditions (chromatographic columns,mobile phases, gradient elution programs), ratios of characteristics pigment to chlorophyll afor CHEMTAX. Eventually, the HPLC analysis method of ultraphytoplankton photosyntheticpigment was formed, chemical taxonomy of ultraphytoplankton based on HPLC pigmentanalysis was established. Specific methods was introduced in the text.In this study, the compositions and spatio-temporal variation of photosynthetic pigmen inthe ultraphytoplanktons of the Three Gorges Reservoir were analyzed by high performanceliquid chromatography (HPLC) and then explored the community compositions and itsinteraction with environmental factors.26sampling points were set in the target research area,covering seven main tributaries in Chongqing, six main tributaries in Hubei and the mainstream. Bimestrial sampling was carried out nine times from August,2012to December,2013,gaining230samples. The main results were as follows:Pure pigments were isolated and purified from pure cultures of algae by HPLC, and thepigments concentrations were calibrated by spectrophotometry. ultimately, eight kinds offreshwater phytoplankton photosynthetic pigment standards were obtained. The pigmentstandrds presented as foundations for quality and quantity analysis of ultraphytoplanktonphotosynthetic pigments from the Three Gorges Reservoir.The main pigments detected in the Three Gorges Reservoir were chlorophyll a, chlorophyll b, fucoxanthin, neoxanthin, violaxanthin, alloxanthin, zeaxanthin and lutein, noperidinin characteristics pigment of dinoflagellate was detected. Pigment concentrationsshowed significant temporal and spatial variation. No significant differences were founded forthe composition of the pigments. Among the pigments, fucoxanthin, alloxanthin, zeaxanthin,chlorophyll b were uppermost proportion in the Three Gorges Reservoir.Sptaio-distribution of ultraphytoplankton biomass presented the main river much smallerthan the tributaries, Chongqing reservoir area superior to Hubei reservoir area. Temporaldistribution of presented the maximum in summer, spring and autumn the second, minimumin winter.Spatio-temporal variation of pigments revealed the characteristics ofultraphytoplankton community composition. The Three Gorges Reservoir was dominated bycryptophytes, diatom, chlorophytes, cyanobacteria. The minimum and maximumconcentrations of chlorophyll a were respectively deteected in December,2012and August,2012. The dominant species showed diatom, cryptophytes, cyanobacteria in December,2012and cryptophytes and chlorophytes in August,2012. Spatio-temporal variation ofultraphytoplankton community composition was connected to the environment factorsincluding water temperature, illumination intensity, nutrient status. Most of the photosyntheticpigments showed significant correlation with temperature, revealed seasonal distributioncharacteristics of the ultraphytoplankton. The spatial difference presented distinct, especiallyin the spring and autumn. The community structure between different sites resulted apparentdifference for the same sampling.