| Based on the surveys carried out in the culture area of Chlamys farreri adjacent to the Liuqing river in May, August, October 2014 and January 2015, this thesis studied the phytoplankton community composition, cell abundance, dominant species in the survey area and the stomach of Chlamys farreri by using conventional method(microscope) and chemical analysis of High Performance Liquid Chromatography(HPLC) method, discussed the total particulate material(TPM) and particulate organic matter(POM) concentration, the similarity comparison between the phytoplankton in survey area and the stomach of C. farreri. It provides basic data for study on the feasibility of the HPLC and the impact of the phytoplankton community structure changes on shellfish feeding, not only a useful supplement, but also provides the information which the traditional classification method unable to provide, it can enrich and improve the understanding of the feeding shellfish and phytoplankton community structure.A total of 3 phyla, 53 genera and 106 species of phytoplankton were identified from the survey area by using microscope, which included 37 genera and 76 species of Bacillariophyta, 14 genera and 28 species of Pyrrophyta, 2 genera and 2 species of Chrysophyta. Diatoms and dinoflagellates were the predominant forms. Total abundance of phytoplankton cells changed in 14.31~70.29×104 cells L-1, and the average was 37.16×104 cells L-1, with the mean of winter was the highest and the autumn was the lowest. Total diatom cells abundance changed in 11.6~67.59×104 cells L-1, and the average was 32.74×104 cells L-1; total dinoflagellates cells abundance changed in 1.79~6.81×104 cells L-1, and the average was 4.14×104 cells L-1; total chrysophyte cells abundance changed in 7.4~63.7×102 cells L-1, and the average was 2.81×103 cells L-1. The highest diatom cells abundance appeared in winter, followed by summer. The dinoflagellates cells abundance decreased gradually, with a small recovery in winter. The chrysophyte cells abundance showed a trend of rise before lower. The phytoplankton cells abundance between surface layer and 5 meters layer changed little every months. The main species of phytoplankton in spring were diatoms and dinoflagellates, the main dominant species was Nitzschia longissima(Y=0.190). The main species in summer was diatoms and the main dominant species was Skeletonema costatum(Y=0.402). The main species in autumn were diatoms and dinoflagellates, the main dominant species was Pseudo-nitzschia delicatissima(Y=0.105). The main species in winter was diatoms and the main dominant species was Asterionopsis glacialis(Y=0.180). During the investigation, the richness index of phytoplankton community in survey area changed in 2.75~4.50, the average was 3.76±0.48, which was highest in summer and lowest in spring; the phytoplankton Shannon- Wiener index changed in 3.15~4.69, the average was 4.04±0.34, which was highest in autumn, followed by spring; the species evenness index changed in 0.56~0.89, the average was 0.76±0.08, which was shown as: autumn > spring > winter > summer.A total of 3 phyla, 36 genera and 55 species of phytoplankton were identified from the stomach of Chlamys farreri by using microscope, which includes 25 genera and 38 species of Bacillariophyta, 10 genera and 16 species of Pyrrophyta, 1 genera and 1 species of Chrysophyta. Diatoms, dinoflagellates and chrysophyte were found in the stomach every month, and diatoms were the predominant forms. Total abundance of phytoplankton cells changes in 191~3383 cells, and the average was 1201 cells, with the mean of winter was the highest and the spring was the lowest. Total diatom cells abundance changed in 105~1892 cells, and the average was 819 cells; total dinoflagellates cells abundance changed in 7~1353 cells, and the average was 288 cells; total chrysophyte cells abundance changed in 0~482 cell, and the average was 94 cells. The diversity of phytoplankton dominant species in the stomach between four months was small. The main species in spring and summer were diatoms and dinoflagellates, the main dominant species was Thalassiosira sp.. The main species in autumn were diatoms and chrysophyte, the main dominant species was Paralia sulcata. The main species in spring were diatoms, dinoflagellates and chrysophyte, the main dominant species was Thalassiosira sp..The phytoplankton composition similarity between stomach and survey area was shown as: spring(72.73%)> winter(65.4%)> summer(59.3%)> autumn(55.7%). The phytoplankton abundance percentage similarity was: spring(46.03%)> autumn(27.08%)> summer(25.50%)> winter(14.92%). The Ivlev index of dinoflagellates and chrysophyte were higher than diatoms, with the highest was Scrippsiella trochoidea, followed by Dinophysis fortii.This thesis found a total of eight kinds of phytoplankton groups by using HPLC, which includes diatoms, dinoflagellates, prymnesiophytes, chrysophytes, cryptophytes, chlorophytes, prasinophytes and cyanobacteria. Diatoms, chlorophytes and cryptophytes were the predominant forms. The total phytoplankton biomass in four months were 97.16μg Chl a L-1、116.52μg Chl a L-1、39.54μg Chl a L-1 and 144.27μg Chl a L-1 respectively, the highest was found in winter and the lowest in autumn.The main groups were chlorophytes(32.78μg Chl a/L) and diatoms(23.99μg Chl a/L) in spring, which were diatoms(47.67μg Chl a/L) and cryptophytes(15.14μg Chl a/L) in summer and diatoms in autumn. The biomass of diatoms was the highest in winter(94.18μg Chl a/L). Diatoms, dinoflagellates, prymnesiophytes, chrysophytes and prasinophytes were found in the stomach of Chlamys farreri. The phytoplankton composition similarity between stomach and survey area was higher in winter and summer and the phytoplankton abundance percentage similarity was higher in autumn,. The Ivlev index of dinoflagellates, prymnesiophytes, chrysophytes and prasinophytes were higher than cryptophytes, chlorophytes and cyanobacteria.The Ivlev index of dinoflagellates and chrysophytes was higher than diatoms, this is same with the result by using microscope, the biomass of diatoms and dinoflagellates are characterized by significant correlation between the two methods, and the stability, precision, parallelism, reproducibility of HPLC were good, these shows that the analysis results of phytoplankton in water and in stomach of C. farreri by using HPLC are reliable. Overall, the main phytoplankton groups in the survey area were diatoms, chlorophytes and chrysophytes, the biomass of phytoplankton were shown as: winter> summer> spring> autumn. The main phytoplankton groups in the stomach of C. farreri were diatoms and dinoflagellates. C. farreri select dinoflagellates, prymnesiophytes, chrysophytes and prasinophytes actively, and the Ivlev index of dinoflagellates was highest. |
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