Study on determination of bio-available phosphorus and bio-activity in aquatic environments by radioisotropic method.

用放射性各向同性方法测定了日本的l.c asumigaura、l.c lucerne和瑞士的L.Greifen及其入流河流的磷吸收速率和平衡后的比值。通过Riger法测定环境有效磷浓度，比较了添加不同的^<32>PO_4-P浓度和^<32>PO_4-P的样品的^<32>P吸收率。研究结果如下：(1)河流样品的磷周转时间在1 ~ 100 h之间，明显长于卢塞恩（L.Lucerne）贫营养化湖泊和卡苏米戈拉（L.Kasumigaura）和格雷芬（L.Greifen）富营养化湖泊。污染程度较轻的河流周转时间较长，说明水体中微生物对磷的供给率较高。(2)污染越严重的河流，颗粒物与溶解组分的平衡比值越高；该比值主要反映了微生物的生物量和生物活性。(3)环境有效磷浓度范围为0.01 ~ 0.1 ug/l，小于比色法测定的可溶性活性磷浓度的十分之一。(4) ^<14> c -葡萄糖的摄取速率与^<32>PO_4-P的摄取速率基本成正比。这一事实表明，磷吸收可能归因于异养活动。此外，还对Hinuma河周边植物生物量的变化进行了观测和模拟。

The P uptake rates and the ratios after the equilibrium were measured radioisotropically for the samples obtained in L.Kasumigaura (Japan), L.Lucerne, L.Greifen (Switzerland), and their influent rivers. The determination of ambient available P concentrations were also performed by the Riger assay approach, in which the ^<32>P uptake rates were compared for the samples added different ^<32>PO_4-P concentrations as well as ^<32>PO_4-P.The results are as follows ;(1) The P turnover times of the river samples ranged from 1 hour to 100 hours, which were considerably longer than those of the samples obtained in L.Lucerne (oligotrophic lake) and the epilimnions of L.Kasumigaura and L.Greifen (eutrophic lakes). The less polluted river had longer turnover time, which indicated the relatively high supply rate of P for microorganisms in water.(2) The higher ratios fo particulate to dissolved components at equilibrium were obtained in more polluted rivers ; then this ratio mainly reflected the biomass and bioactivity of the microorganisms.(3) The ambient available P concentrations ranged from 0.01 ug/l to 0.1 ug/l, which were less than one tenth of soluble reactive phosphorus determined colorimetrically.(4) The uptake rates of ^<14>C-glucose were nearly proportional to those of ^<32>PO_4-P.This fact suggests that the P uptake is possibly attributable to heterotrophic activities.In addition, the change in the periphyton biomass was observed and simulated in Hinuma River.