| Sinonovacula constricta is widespread in China. It has a filter-feeding life, andlives in estuary and inner bay. Potamocorbula laevis is widespread in the coastal regionsof China, is a kind of important food organism. Corbicula fluminea is a kind ofimportant economic freshwater shellfish,and widely lives at the bottom of rivers, lakes,ditches and ponds in the north and South of China. In this paper, filtration rate, ingestionrate, assimilation rate, activity of SOD and CAT under different salinities; carbonbudget nitrogen budget and ecological service value of S. constricta, C. fluminea, P.laevis were studied.The main results were as follows:1. The experiment measured the activities of SOD and CAT of Sinonovaculaconstricta, Potamocorbula laevis, Corbicula fluminea under different salinities andsudden increase of salinity. S. constricta were exposed to eight different salinities（3,4.3,6.1,8.6,12.2,17.3,24.6,35）; P. laevis were exposed to seven different salinitie（s3,4.4,6.4,9.4,13.9,20.4,30）; C. fluminea were exposed to eight different salinities（0,1,1.8,3.1,5.5,9.7,17.1,30）. The results show there were significant differences (P＜0.05)in activities of SOD and CAT of three filter-feeding bivalves under different salinities.These two enzymes varied similarly and both increase firstly and then decrease with therise of salinity. During the salinity shock experiment, we find out that with the suddenincrease of salinity, the two enzymes’ activity of three filter-feeding bivalves bothimproves significantly. But with the continuous increase of the salinity, the enzymeactivity tends to decrease. The results indicate that Salinity8.6~24.6,6.4~20.4and0~5.5are suitable salinity ranges of S. constricta, P. laevis and C. fluminea respectively.2. The effects of salinity on filtration rate, ingestion rate and assimilation rate ofthree filter-feeding bivalves in Yangtze River estuary were researched using the indoorexperimental ecological methods.The group of Sinonovacula constricta was set up sixsalinity grads（5,10,15,20,25,30）. Potamocorbula laevis was set up six salinity grads （5,10,15,20,25,30）. Corbicula fluminea was set up six salinity grads（0,5,10,15,20,25）. And the biological parameters of three filter-feeding bivalves were measured.The results showed the filtration rate, ingestion rate and assimilation rate of threefilter-feeding bivalves increased along with increasing salinity, reached a peak levelwhen the salinity rises to a certain point, then dropped in the wake of increasing salinity.The filtration rate, ingestion rate and assimilation rate of S. constricta reached the peaklevel at the salinity of20, were0.57L·h-1,5.38mgPOM·h-1and0.72%respectively. Thefiltration rate and assimilation rate of P. laevis reached the peak level at the salinity of10, were0.46L·h-1and0.53%respectively. The ingestion rate reached the peak level3.80mgPOM·h-1at the salinity of15. The filtration rate and ingestion rate of C. flumineareached the peak level at the salinity of15, were0.39L·h-1and2.48mgPOM·h-1respectively. The assimilation rate had reached the peak level0.51%at the salinity of0,and dropped in the wake of increasing salinity. The above results indicate that thesalinity has a big impact on the three Feeding physiology indexes of three filter-feedingbivalves.3.Sinonovacula constricta, Potamocorbula laevis, Corbicula fluminea were usedas the research object in Yangtze River estuary in spring. The feeding physiologicalparameters of three filter-feeding bivalves were measured.And the carbon and nitrogenbudgets of three main bivalves were estimated according to energy balance principle.The result indicated that①the three kinds of bivalves obtained carbon source byfiltering unicellular algae, the main parts were consumed by breathing and directlydischarged as dejection,a small part was discharged by excretion. The remaining carbonwas used for its growth and development. the carbon balance equation of S. constrictawas100.00C（feeding carbon）=20.17F（dejection carbon）+50.05R（breathing carbon）+9.86U（excretion carbon）+19.92P（growing carbon）, the carbon balance equationof P. laevis was100.00C=44.13F+33.08R+11.05U+11.74P,the carbon balanceequation of C. was100.00C=31.29F+37.40R+5.05U+26.26P.②Since bivalves donot discharge nitrogen in the respiratory metabolism, the three bivalves’s growingnitrogen made up more part of the total feeding nitrogen than those of carbon. Thereforethe nitrogen balance equation of S. constricta was100.00C（feeding nitrogen）=28.22F（dejection nitrogen）+49.38U （excretion nitrogen）+22.40G（growing nitrogen）,the nitrogen balance equation of P. laevis was100.00C=46.97F+32.95U+20.08G,the nitrogen balance equation of C. fluminea was100.00C=45.05F+23.99U +30.96G. |
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