Study On Seasonal Variation Of The C、N、P、Si Budget Of The Bivalves In Sungo Bay

The feeding physiological parameters of three main cultured bivalves Scalloppatinopecten yessoensis,Chlamys farreri,and Pacific oyster were measured in springof Sungo bay by semi-in situ flow-through method. The C、N、P budgets can beestimated according to energy balance principle. The result indicated that most of theobtained carbon were consumed by breathing, some parts becomed the organismcomposition of the bivalves for its growth, some parts was discharged by excretion,and the remaining little carbon were directly discharged as dejection; while most ofthe obtained N、P becomed the organism composition of the bivalves for its growth,a little was directly discharged as dejection, the remaining little was consumed bybreathing and excreting; moreover, the bivalves accumulated N more than C andP.Results were listed as follows:①The bivalves could filter lots of seawater to ingest, and have influences on theirecosystems through excretion and biodeposition.②The experiment sample every two month, the result shows the growth ratesbetween the three bivalves were difference along with the season, as the shell high,the mean rates were:327um/d、123um/d and40.5um/d; while in different seasons,the percent of C、N、P、Si have no significant difference.③In this study, there are two plankton samples by trawling in October andDecember2013, the results show that winter was higher than autumn of thebiodiversity index,there was no obvious various in the speciese of phytoplankton,while, autumn was totally higher than winter in the number, mostly was diatoms; Thezooplankton was arthropod mostly, the speciese was high in autumn, contrary to thenumber.The main food sourse was phytoplankton which have a close relationship tothe source of the particulate organic matter, the contribution ratio was differenceamong the bivalves.④The study used the breathing bottle and biological deposition method, the resultsshow the average ingestion rate of patinopecten yessoensis,Chlamys farreri,andPacific oyster is0.453mg/h/ind、0.407mg/h/ind and0.278mg/h/ind, the percent of the four elements is no difference in the biodeposition; The excretion rate is variousamong the bivalves in the same season, the rate is increasing with the indivivaul,while the Si excretion is almost the same. The absorption rate and the absorptuionefficiency have a positive relationship with the POM, when the pseudofaeces producethe TPM are19.56、16.44and17.76mg/L.⑤The C、N、P、Si budget have a important role in the element source or sink,this study analyses the ingestion、respiration、excretion and the biodeposition rate toevaluate the C、N、P、Si budget. The results show that the ingestion of C、N、P、Si have vividly difference, the Chlamys farreri is always higher than Patinopectenyessoensis and Pacific oyster, the percent of C return into the water through excretionis35.92%、43.36%and39.16%, the N is49.03%、54.49%and51.98%，the P is30.00%、37.59%and34.43%，the Si is32.45%、36.87%and59.60%, the Pacificoyster is higher than the others obviously; the percent of C deposit to the bottom ofsea is53.26%、38.09%and39.51%，the N is38.83%、26.23%、26.09%，the P is62.84%、45.55%、44.69%，the Si is63.59%、52.51%and27.51%, the Pacificoyster is lower than the others obviously; the percent of C removed out of water is10.28%、18.55%and21.33%，the N is12.41%、19.27%and21.93%, the P is7.36%、16.86%and20.88%, the Chlamys farreri is the lowest of all, the Si is13.39%、3.96%and10.61%, the Patinopecten yessoensis is the lowest.