湖北汉阳沉湖泛区浮游物的现存量与化学组成

本文报道了武汉市汉阳县沉湖泛区1983年5至9月浮游物(eston)的现存量与化学组成的动态,并根据该泛区的生态特征,分别对枯水期、灌江期和丰水期浮游物的干重(DW)、无灰干重(AFDW)、灰分重(Ash)、碳(C)和氮(N)量的变动特性进行了比较研究,而且还在此基础上,进一步探讨了评价浮游物营养质量的指标。沉湖泛区1983年5至9月浮游物干重为5.24mg/L,其中无灰干重为2.55mg/L,灰分重为2.69mg/L,它们均以灌江初期为高;碳、氮量分别为0.830和0.193mg/L,前者高峰出现在丰水后期,后者出现在灌江初期;浮游物干重、无灰干重、灰分重、碳和氮量均以灌江结束期为最低。浮游物的无灰干重、灰分重、碳和氮量分别占干重的51.60、47.50、18.30和3.90%;碳和氮量分别占无灰干重的36.40和7.70%。沉湖泛区浮游物的无灰干重/灰分重平均为1.24,碳/氮平均为4.74。这两个参数可分别作为评价沉湖泛区浮游物营养质量的指标。沉湖泛区浮游物干重、无灰干重、碳和氮量间,浮游物无灰干重与其灰分重、碳、氮量间,浮游物碳、氮量间均存在着极显著的相关关系,表明它们之间相应的动态是一致的。  

THE STANDING CROP AND CHEMICAL COMPOSITION OF SESTON IN CHENHU FLOODING AREA, HANYANG, HUBEI

The standing crop and chemical composition of seston were investigated in 1983 in Chenhu flooding area, Wuhan. During the surveying period from May through September, the average DW (dry weight), AFDW (ash-free dry weight), Ash, C(carbon) and N (nitrogen) of sestonic standing crop were 5.24, 2.55, 2.69, 0.830 and 0.193 mg/1 respectively, which were all lower than those reported in eutrophic lakes by some authors. The seasonal changes of sestonic standing crop were prominent. The highest concentrations of DW, AFDW, Ash and N were recorded in the start of filling, coincident with great input of allochthonous seston, but the highest concentration of C was recorded in the late high water level phase, coincident with the formation of detritus in great amounts during the decomposition of plant litter; the lowest concentrations were all recorded just before the end of filling because of great sedimentation rate of seston. It was estimated that the concentrations of AFDW, Ash, C and N of seston were equivalent to 51.60, 47.50, 18.30 and 3.90% of its DW; the concentrations of seston C and N were equivalent to 36.40% and 7.70% of its AFDW. The average AFDW/Ash and C/N were 1.24 and 4.74. These two parameters could be used to assess the nutritive quality of seston in aquatic ecosystems. The significant linear relationships between DW and AFDW, C, N; between AFDW and Ash, C, N; and between C and N were all established, which indicated that they changed in the same manner.