Phosphorus fractionation in different trophic sediments of lakes from different regions, China

Abstract

The characteristics of organic phosphorus (P_o) fractions in the sediments of nine lakes from the middle and lower reaches of the Yangtze River region, Yungui Plateau, Qinghai–Tibet Plateau, Northeast China Region, and Mongolia–Xinjiang Plateau, China were investigated and the differences of the different lakes on P fractionation was discussed. The results indicated that organic matter (OM) showed significant positive correlations with P_o in sediment samples, and the rank order of the P_o fractions was: residual P_o > HCl–P_o > fulvic acid–P_o > humic acid–P_o > NaHCO₃–P_o with mean relative proportions 7.4 : 3.4 : 2.4 : 1.7 : 1.0. The labile and moderately labile P_o were the main fractions in the sediments for shallow eutrophic lakes except for Lake Qilu, however, nonlabile P_o was dominant in the sediments from deep lakes. Labile P_o was significantly correlated with total phosphorus (TP), inorganic phosphorus (P_i), P_o, NaHCO₃–P_i, HCl–P_i and NaOH–P_i, and the nonlabile P_o was significantly and positively related to OM, TP, P_o and NaOH–P_i.