| The Yangtze River is the largest river in China’s inland waterway transport. The middle reaches of the Yangtze River, i.e. Jingjiang River beach has always formed the "bottleneck" of the Yangtze golden waterway. For dredging the "bottleneck" of the Yangtze River Waterway, the government performed the full implementation of Jingjiang Channel Regulation Project-the Middle Reaches of the Yangtze River in September 2013. the scope of the project is the Changmenxi to xiongjiazhou, Full length 347.2 km, the project mainly includes the beach protection zone, deep groove bottom protection, high guard, reinforcement and so on. To study the construction of river engineering in aquatic organisms (phytoplankton, zooplankton and zoobenthos) communities characteristics influence, This thesis focuses on the construction method, physicochemical properties of water and phytoplankton, zooplankton, benthic biological communities characteristics, selection of nine construction section of the river (Zhijiang, Shashi, Jiangling, Xinchang, Shishou, Tiaoguan, Tashiyi, Sanzhou, Dongtinghuikoushang), By 2013-2015 during normal water period and low water period in the survey section of water physicochemical factors and aquatic taxa of investigation and analysis, a preliminary study of the influence of Jingjiang river channel improvement project of the aquatic community, and has made the preliminary analysis and the discussion to the reason which produces the influences,in order to investigate the influence of Jingjiang river channel improvement project on plankton and zoobenthos communities to provide information for further study of waterway regulation engineering of river ecological effect and ecological effect evaluation of reference.The main results are as follows:(1) During the investigation were detected in phytoplankton 7 phyla 59 genera and 175 species, compared with before construction (7 phyla 48 genera and 125 species),50 genera and 11 species were added; Species composition in the proportion of the construction before and after the change is not, are Bacillariophyta> Chlorophyta> Cyanophyta, the proportion of other categories of smaller; In the dominant species, Asterionella formosa in Bacillariophyta, Pediastrum simplex in Chlorophyta, Oscillatoria sp. in Cyanophyta, were the dominated species which not much before the construction, prior to the construction of the dominant species of Gomphonema sp. during the survey rare.During the investigation were detected in zooplankton 66 genera and 111 species, compared with before construction (70 genera and 165 species),50 genera and 11 species were reduced; The zooplankton community was mainly composed of Protozoa(42.34%), Rotifera(22.52%), Copepods(18.92%), Cladocera (16.22%), compared with the prior to construction, the proportion of rotifera decreased 10.2%, copepods increased 9.07%, protozoa and cladocera had little change; In the dominant species, Simocephalus vetulus in Cladocera, were the dominated species which not much before the construction, prior to the construction of the dominant species of Polyarthra trigla during the survey rare.During the investigation were detected in zoobenthos 23 genera and 25 species, The zoobenthos community was mainly composed of Mollusca(64%), Arthropoda(28%), Annelida(8%); compared with the prior to construction, the proportion of mollusca increased 25.54%, arthropoda decreased 25.85%, annelida had little change; The dominant species of zoobenthos changed greatly before and after construction, Limnoperna lacustris were the dominated species, prior to the construction of the dominant species of Procladius sp.,Palaemon sp.,Palaemonetes sp are during the survey rare.(2) Comparison of survey data before construction, phytoplankton density and biomass were 124731.56 ind./L and 0.3934 mg/L, respectively,162924.44 ind./L and 0.1942 mg/L were reduced before construction; zooplankton density and biomass were 250.32 ind./L and 0.4833 mg/L, respectively,39.12 ind./L and 0.4466 mg/L were induced before construction; zoobenthos density and biomass were 16.92 ind./m2 and 4.519 g/m2, respectively,4.92 ind./m2 and 2.439 g/m2 were induced before construction.(3) The largest number of species of phytoplankton in the spring (April 2014),165, at least in the autumn (November 2013),73; its density was highest in spring (April 2015), was 241444 ind./L, and the lowest was also appeared in spring (April 2014), which was 20417.11 ind./L; the highest biomass appeared in winter (November 2014), was 0.7658 mg/L, and the lowest was also appeared in winter (November 2013), and was 0.0443 mg/L; In winter showed changes of phytoplankton species decreased in spring increased, biomass changed irregularly.The largest number of species of zooplankton in the spring (April 2015),96, at least in the winter (November 2013),34; its density was highest in spring (April 2014),509.44 ind./L, lowest in winter (November 2013), was 66.25 ind./L; biomass in the highest in spring (April 2015),113.6 mg/L, and the lowest appeared in the spring (April 2014),0.0234 mg/L; in zooplankton species changes in spring and summer was significantly higher than that in autumn and winter, biomass also showed in spring and summer than in autumn and winter, but the difference was not obvious.Zoobenthos species appear most frequently in the autumn (November 2013) and 23 species, at least in the spring (April 2015),12; density is the highest in winter (November 2013),40 ind./m2, the minimum appears in the autumn (November 2014), 3.91 ind./m2; biomass was the highest in winter (November 2013),8.2902 g/m2, minimum in autumn (November 2014),1.3611 g/m2; zoobenthos species biomass changes had no obvious regulation, judging from the spatial distribution, in addition to the phytoplankton species generally showed a river upstream than downstream, phytoplankton biomass, zooplankton species and biomass, zoobenthos species and biomass level had no obvious regularity.(4) Jingjiang reach of Yangtze River upstream to downstream of the nine sampling transects. Due to the water physical and chemical factors of complexity, characteristics and spatial differentiation.The water depth, oxidation-reduction potential, transparency, NH4+-N, NO3--N, flow rate and other factors change relatively large, pH, temperature, dissolved oxygen, conductivity, salinity, light intensity, total dissolved solids and other factors are relatively small, the dominant factors of each section are not consistent, and the effects of water physical and chemical factors on phytoplankton, zooplankton and zoobenthos communities are different. The results of canonical correspondence analysis (CCA) indicate that:dissolved oxygen, water temperature, total dissolved solids are the main environmental factors that influence phytoplankton community, salinity, transparency, NH4+-N, N03"-N, is the main environmental factors that affect the zooplankton community, total dissolved solids, NH4+-N, flow rate is the main environmental factors that influence on zoobenthos community.(5) Different construction methods on phytoplankton, zooplankton and zoobenthos are different, the influence of phytoplankton on the filling tank is the most significant(P <0.01), zooplankton was most affected by the guardian reinforcement project(0.01<P <0.05), zoobenthos was most affected by the guardian reinforcement project(P<0.01).(6) The ecological cone of the number of individuals and biomass among different aquatic groups,the number of Pyramid showed positive morphology;In the biomass of Pyramid, are not in line with the normal form of the law, by the impact of the size of the individual organism, Tashiyi section showed a negative form, the other showed secondary consumer> producer> primary consumer. |
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