新闻动态

分光光度法和离子色谱法测定浅水湖泊水中溶解性磷酸盐的差异

作者Yi, RongSong, PeixueLiu, Xin;

Phosphorus (P) plays important roles in aquatic ecosystems, but accurately determining phosphorus species (particularly bioavailable phosphate) is difficult. When phosphate concentrations are spectrophotometrically measured as soluble reactive P (SRP), the actual values are often overestimated. Ion chromatography is one method for accurately measuring orthophosphate concentrations. To clarify how the spectrophotometrical measurement overestimates actual phosphate concentrations, we compared estimates of phosphate concentrations in lake waters using both methods. SRP and orthophosphate concentrations in water samples collected from four shallow lakes around Lake Biwa, Japan, were determined monthly for 1 year by spectrophotometry and ion chromatography, respectively. SRP concentrations were frequently higher than those for orthophosphate in all lakes throughout the study period, suggesting that SRP and orthophosphate are not equivalent, although a significant relationship was found between them. Orthophosphate/SRP (ortho/SRP) ratios varied spatiotemporally in all lakes (range 0.11-1.04; mean 0.56), being well predicted by biological-mediated relevant parameters using a stepwise multiple logistic regression analysis (R-2 = 0.76). The results implied that organic matter associated with biological activity contributes to the variability in ortho/SRP ratios. Such large variability in ortho/SRP ratios emphasizes the importance of accurate orthophosphate estimates for understanding P dynamics in aquatic ecosystems.

LIMNOLOGY   :  21   :  3   特刊:  SI   :  329-339   出版年:  2020