| Kuli Pool, which is located in the Qianguo county, Jilin Province, is a natural lake and an important base for fish breeding as well. As a typical wetland, the pool and its surroundings helps a lot in keeping ecological balance, regulating local climate and accelerating economy development. In 1978, Changshan thermo electric plant was founded and Kuli Pool was used as cool water and drainage area, thus the temperature of some parts enhanced significantly, which leaded to great changes in composition and biomass. From high temperature shock and mechanical force in the power plant cooling system to discuss the entrainment injured rate of plankton and their recovering speed after they are damaged by the power plant.In May,July,September,2006,and in January,2007, we have done the evaluation and statistics of biomass and category of planktons (bait material biological) in Kuli Pool for four times. In order to study comprehensively and accurately, we also carried on the temperature and the speed of flow with drawing them. According to the speed lines we choose the point where we gather samples .Later we carry on the appraisal and the statistics of the biological type and the quantity of plankton and analysis the relation between speed of flow and biomass. The test result is as follows:(1)It is taken the draining water influence the Changshan thermal power plant, in the storehouse soaks the speed of flow situation and the natural water body is different, forms lives by the wind flows and circulates flow velocity field (mainly by draining water momentum which the fluent synthesis becomes restricts).In various seasons because of power rate different, creating the speed of the cooling water to discharge and the withdrawal changed, the speed of flow also along with it changing , but synthesizes looked, its flow velocity field distributed situation basic maintenance stable, according to the determination data speed of flow scope is 0.019～0.18m/s, and the water drainage speed of flow is biggest, the average achieves is 1.72m/s in the whole year.(2)the biomass result investigated indicates that, In floats the plant aspect, kinds of Bacillariophyta there are more 10 kinds than 1982's, but the out standing fish food like Cyanophyta, Chlorophyta, Euglenophyta and so on algae all have in the certain degree in the type reducing .In May sampling, the Chlorophyta drops 14 kinds in particular. Cyanophyta the center Microcystis the algae is dominant species. In the zooplankton aspect, compared with 1982 investigation floats moves the species number to reduce the nearly 80 kinds, protozoon reduced most achieves about 50 kinds, next is Rotifera and Cladocera but copepods increased 5 kinds. Besides a turn of insect, the zooplankton biomass various seasons are lower than the biomass in the 80's same seasons. The processing data obtains biomass along with type station change curve, because experiment is deferred to the speed of flow the size to carry on the sampling spot, and in fact it also may be regarded as the curve which obtains along with the speed change. We may see from the curve, the plankton quantity,the quality have the tendency which reduces along with the speed of flow increase.According to the tentative data, we calculate the Changshan thermal power plant to soak the water body plankton to the storehouse in the loss situation with two methods and carries on restores the speed trial. this result and biological shape structure related, Easily damaged is mainly some kinds of Cyanophyta,Chlorophyta, with the builds are bigger and the structure is easily destroyed .The results show that the damaged rate of the algae is 17.9～26.9 percent.. The damaged rate of the zooplankton is 67.7～75.5percent ,the most serious damaged species by the power plant are Copepods and larval plankton.(4)the damaged plankton to restore the speed trial results that, according to the restored curve, the injured floating algae's to restore to the level as before that need 48 hours; the injured animal to restore is the protozoon which the time is quickest, approximately about 36～48 hours. In the experimental 72 hours, Cladocera the quantity restores original to 4/5, completely restores the time approximately is 80～90 hours; copepods restores to the original quantity 1/3, completely restores the time approximately is 160～180 hours. The Rotifera restoration speed is relatively stable, which basically can restore in the experimental number of days to the original quantity, estimated according to the curve, restores the time about 60～84 hours. But regardless of is the zooplankton or floats the plant, growing non- upper limit is impossible. After achieving the load bearing limit of this experimental environment, the restoring can tend to stably, even drops the tendency. But in time of the experiment carries on it may regard as to continue to assume the exponential growth. The fastest of the recovered is Protozoan after it has been damaged , and the most slow is Copepods.The Changshan thermal power plant use Kuli Pool to be the cooling pond, with the water volume in summer is 15.48m3/s,in winter is 10.86m3/s. According to the date of open-air experiment in May, in July, in September and in January, with the result is : Summer-circulates–time of the entire lake water cycle is 343 hours, about 14 days; The winter-circulates-time of the entire lake water cycle is 489 hours, it approximately is 20 days. Because the cooling water is impossible in the entire lake scope to use, there is only 25%～35% lake water to join the refrigeration cycle. According to the above converts, circulates in summer one time takes 3～5 days, the winter's time is 5～7 days. Referenced the zooplankton's restoration speed trial result we can know that the algae, protozoon which restore more quickly ,and their entrainment effect may be weaker; because the time of Rotifera, copepods and Cladocera carried to the cycle is shorter ,the biomass has not restored to the original level .Entering the next time to circulate once more and such whole year long-term circulation reciprocation, the result of entrainment effect is becoming serious. |
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