盐度对湿地枯落物分解过程中碳氮磷化学计量比的影响

Effect of salinity on carbon,nitrogen and phosphorus stoichiometry during the decomposition of wetland litter

为了阐明盐度对枯落物分解过程中碳氮磷化学计量比的影响,采用分解袋法对闽江河口湿地不同盐度条件下短叶茳芏枯落物和芦苇枯落物分解过程中生态化学计量学特征进行了测定.结果表明,盐度较高的生境,枯落物具有较快的分解速率、氮和磷的释放速率,较慢的碳和能量释放速率;整个分解期间内,枯落物C/N呈下降的趋势,C/P和N/P表现为先上升后下降的趋势;高盐度生境短叶茳芏枯落物和芦苇枯落物分解过程中平均C/N、C/P和N/P分别为34.3和36.4、1210.4和1710.3、35.4和47.1;低盐度生境短叶茳芏枯落物和芦苇枯落物分解过程中平均C/N、C/P和N/P分别为33.2和35.1、1170.0和1636.8、35.9和47.3;高盐度生境短叶茳芏枯落物和芦苇枯落物C/N、C/P高于低盐度生境,N/P低于低盐度生境;较低的枯落物碳与养分比值具有较高的能量释放.

In order to clarify the effect of salinity on carbon, nitrogen and phosphorus stoichiometry during the decomposition of wetland litter, the ecological stoichiometry characteristics of Cyperus malaccensis var. brevifolius, Phragmite australis litter from Minjiang River estuarine wetland under different salinity conditions were analyzed using mesh bags method. The results showed that, in higher salinity habitat, litter had higher decomposition rate, nitrogen （N） and phosphorus （P） release rate, and lower carbon （C） and energy release rate. The C/N was declined, and C/P and N/P were increased and then declined during the litter decomposition. In higher salinity habitat, the values of litter C/N, C/P and N/P of C. malaccensis and P. australis were on average 34.3 and 36.4, 1210.4 and 1710.3, 35.4 and 47.1 during the litter decomposition, respectively. In lower salinity habitat, the average values of C/N, C/P, N/P of C. malaccensis var. brevifolius and P. australis litters were 33.2 and 35.1, 1170.0 and 1636.8, 35.9 and 47.3 during the litter decomposition. The C/N and C/P of C. malaccensis var. brevifolius and P. australis in higher salinity habitat were higher than that of lower salinity habitat, but N/P was lower than that of lower salinity habitat. The lower carbon to nutrient ratios indicated a higher energy release.