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量了日本鹿尾藻、瑞士紫花苜蓿和瑞士格雷芬及其进水河的磷吸收速率和平衡后的磷吸收比。用Riger法测定了环境中有效磷的浓度，比较了添加不同浓度的32&gt；PO_4-P和32&gt；32&gt；PO_4-P的样品对磷的吸收速率。结果表明：(1)河流样品的磷周转时间为1~100小时，显著长于紫花苜蓿(富营养化湖泊)和紫花苜蓿(富营养化湖泊)的样品。(2)污染程度较高的河流中，颗粒组分与溶解组分的平衡比例较高，这主要反映了微生物的生物量和生物活性。(3)环境有效磷浓度在0.01ug/L~0.1ug/L之间，不到比色法测定的可溶性活性磷的十分之一。这表明磷的吸收可能与异养活动有关。此外，还观察和模拟了Hinuma河的附生生物生物量的变化。

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.