Effects of temperature on the nitrogen and phosphorus excretion of <i>Corbicula fluminea</i>

Abstract

在不同温度下,对太湖河蚬进行了室内短期氮、磷释放模拟实验.结果表明,温度对河蚬(Corbicula fluminea)不同形态氮、磷的排泄都有重要的影响.总磷(TP)、总氮(TN)、总溶解性氮(TDN)、总溶解性磷(TDP)和正磷酸盐(PO₄^3--P)排泄率随温度的升高都显著升高,而亚硝态氮(NO₂^--N)排泄率先升高后下降.铵态氮(NH₄⁺-N)排泄率在5和15℃间变化不显著,温度对硝态氮(NO₃^--N)排泄率有影响但不显著.同时实验发现河蚬为排氨动物,NH₄⁺-N排泄占TN排泄的50.78%~100%,TDN排泄占TN排泄的89.14%~100%,而NO₃^--N、NO₂^--N虽都有检出,但所占比例相对较小.在河蚬磷排泄中,TDP占TP比例范围为83.01%~100%,PO₄^3--P在36.60%~96.59%之间,且所占比例都有随温度升高而增加的趋势.同时对排泄率与干重和温度之间的关系进行了回归分析,发现不同氮、磷排泄率(NO₃^--N和NO₂^--N除外)与温度和干重的关系均符合方程R(X)=aW^b·e^c^T＋d,决定系数R²都在0.967以上.;A microcosm was established to simulate the short-term nutrient excretion of the Corbicula fluminea which was sampled in the Gonghu Bay, Lake Taihu. The C. fluminea was cultivated at 5, 15 and 25℃ after 24 hours' acclimation. The results showed that temperature greatly affected the nitrogen and phosphorus excretion rate of the C. fluminea. The excretion rate of total phosphorus(TP), total nitrogen(TN), total dissolved nitrogen(TDN), total dissolved phosphorus(TDP) and phosphate phosphorus(PO₄^3--P) represented a notable increase with the temperature increasing, however, the excretion rate of nitrite nitrogen(NO₂^--N) increased first and then reduced with the increasing temperature. The change in the excretion of ammonium nitrogen(NH₄⁺-N) between 5 and 15℃ was not significant. Temperature had a non-significant effect on nitrate nitrogen(NO₃^--N). We also found that the C. fluminea was ammonotelic benthos, and NH₄⁺-N was the main nitrogenous excretory product which occupied for 50.78%-100% of the TN. TDN accounted for 89.14%-100% of the TN. Although NO₃^--N and NO₂^--N were detected, the amount of them is very little. In the phosphorus excretion, the proportion of TDP and PO₄^3--P to TP were 83.01%-100% and 36.60%-96.59%, respectively, and the proportion of them increased with the rising temperature. Regression analysis between the dry weight, temperature and the excretion rates indicated that the regression equation R(X)=aW^b·e^c^T+d was adaptive to all types of the nitrogen and phosphorus excretion except NO₃^--N and NO₂^--N, and the R square reached over 0.967.