Study On The Characteristics Of Suspended Solids And Evaluation Of Fish Production Potentials In Chenhang Reservoir Of Yangtze Estuary

Chenhang reservoir as one of the important fountainheads in raw water supply playsof Shanghai, give full play to the "avoid and storage of clear" and "avoid salty storageof light" two big functions. But in recent years, because of the Yangtze river basinmany rivers, lakes eutrophication, nitrogen and phosphorus nutrient content of YangtzeRiver rise, which inevitably accelerated Eutrophication of Chenhang Reservoir,exacerbated the deterioration of the water environment.The content of suspended solid in water is the important index to measure waterpollution degree and it is one of a pollutant tracer, so the investigation of suspendedsolid is of significance for lake water quality, ecological environment research anddrinking water safety.This study measured the level of suspended solid of Chenhang reservoir in2010-2011upon ecological environment monitoring of Chenhang reservoir waterenvironment; Analyze nutritional status of Chenhang reservoir basing on total nitrogenphosphorus, chlorophyll a,suspended content and phytoplankton diversity index;Makea primary evaluation of fish production potential of reservoir through suspended solidand primary productivity, provide basal scientific basis for stocking predatory fishreasonably, provide basic theory research material of Chenhang reservoir biologicalcontrolling algae. At the same time, it can guide stocking and fishing amount ofpredatory fish quantity, inhibit outbreaks of Algal bloom to guarantee the expression ofwater holding capacity. According to the survey, we came to the conclusion that:1, Annual average of suspended content is29.4±7.3mg·L^-1, including inorganic ash content19.3±8.4mg·L^-1, which accounting for65.6%of the annual averagecontent suspended; Annual average of organic debris is10.1±5.7mg·L^-1, whichaccounting for34.4%. Organic clastic proportion which in spring and summer ishigh（42.20%and41.70%, respectively）,and in winter is lowest（22.94%）; Inorganicash, by contrast, was highest in winter （77.06%）,was lower in spring and summer.Seasonal change of suspended solids content register as that it is high in winter andsummer, low in spring and autumn. Seasonal change of inorganic ash content was inaccordance with seasonal change of suspended solids content, seasonal change ofOrganic clastic register as that summer> spring> autumn> winter. The vertical changeof suspended solids register as that4meters water layer> surface water layer>2meters water layer>1meters water layer> transparency>0.4meters water layer. Thevertical change of inorganic ash content basically in accordance with change ofsuspended solids content, the vertical distribution of organic debris mainlyconcentrated in surface and layer which transparency is0.4m.2, Total nitrogen phosphorus nutrition assessment shows all sites are in reservoirChenhang eutrophication status. Based on chlorophyll a nutritional status of theevaluation （revised nutrition state carlson index evaluation） shows Chenhang reservoiris the degree of mesotropher. The TSIM carlson index （Chl a） month for winterchanges in December the TSIM minimum value, late spring and early summer June theTSIM value is the highest. At the same time, the site of the TSIM carlson index （Chl a）St4site in the highest, and the lowest St2site. The average of revised nutrition statecarlson index evaluation is40.27. Chenhang reservoir evaluation content is29.4suspended mg·L^-1, higher than in rich nutrition level of lakes-mean range, less than richnutrition level lakes mean range, Chenhang reservoir levels of nutrients in richnutrition level. Chenhang phytoplankton Shannon-Weaner diversity index, Margalefdiversity index and Simpson diversity index site change trend consistent, all with thelowest value St2site, other differences were smaller site. From Shannon-Weanerdiversity index evaluation standard evaluation, St2site is in beta and type, other threesites were few corrupt belt; From Margalef diversity index evaluation standard assess, St1-St4sites belong to the beta of type and, from Simpson diversity index evaluationstandard evaluation, St2site is in beta and type, other three sites were few corrupt belt.Three kind of diversity index evaluation result is consistent, but reflected Chenhangreservoir St2site of water quality in the beta and type. This and St2site geographicalposition and orientation of the relevant, St2site is located in the inlet, water quality ispoor.3, Through the suspended solids organic carbon content of silver carps reservoirestimate Chenhang fish potential （PHY） in27.80t, it in the fish potential （PAR） for9.52t,Chenhang reservoir fish in fish filter (total potential for37.32t, can put on the silvercarps15400kg, it560kg, fish species on the specifications20kg-1, the tail. Based onphytoplankton primary productivity of fish production potential, silver carps itaccording to the proportion of5:1fish kept Calculate the yield potential silver carpsfish （PHY） is17.34t, it in the fish potential （PAR） for7.80t, Chenhang reservoir fish infish filter (total potential for25.14t, dropping9660kg silver carps, it420kg.Chenhang reservoir of the benthic animal production potential of37.4kg fish/hm2, canput on the bears are fish5236kg.