Increasing turbidity is the main cause for the disappearance of submersed macrophytes and regime shift from clear-water to turbid-water states along the eutrophication of lakes. Quantitative discrimination on the contribution of algal and non-algal particles to total turbidity (TurbTot) may enhance the understanding on these processes. This study investigated algal turbidity (TurbAlg), non-algal turbidity (TurbNonAlg), and their contribution to TurbTot in percentage (TurbAlg%, TurbNonAlg%) using data from Yangtze shallow lakes. The results showed that both absolute and percentage non-algal turbidity (averaged 0.96/m and 71.0%) were much higher than those of algal turbidity (averaged 0.19/m and 11.0%). Total phosphorus (TP) positively impact TurbAlg and TurbNonAlg, and when TP exceeded 100 μg/L, TurbAlg and TurbAlg% showed accelerated increases while TurbNonAlg% showed a decreasing trend. TurbAlg, TurbAlg% and TurbNonAlg were significantly lower in macrophyte-present lakes than in macrophyte-absent lakes, while TurbNonAlg% was not sig-nificantly different between lakes. TurbNonAlg and TurbNonAlg% increased significantly with decreased biomass of sub-mersed macrophytes (BMac), while TurbAlg and TurbAlg% showed no significant varying trend. In summary, TurbAlg was determined mainly by TP, while TurbNonAlg was greatly determined by ZM, TP, and submersed macrophytes. The fact of continuously increasing TurbAlg and TurbNonAlg along with increasing TP and degrading macrophytes demonstrates that nutrient control and macrophyte maintenance are practically important during the whole process of eutrophication, al-though there exists a threshold for clear-to-turbid regime shifts.%浊度的上升是湖泊富营养化过程中沉水植物消失、由草向藻发生稳态转换的根本原因.研究利用长江中下游浅水湖群区域数据对藻类浊度(TurbAlg)和非藻类浊度(TurbNonAlg)及其对总浊度(TurbTot)的贡献率(TurbAlg%,TurbNonAlg%)进行了推算.结果显示,在该区域非藻类浊度绝对值及其贡献率均普遍高于藻类浊度;TurbAlg主要受限于总磷(TP),而TurbNonAlg受水深(ZM)、TP和沉水植物等多重因素的影响.TurbAlg和TurbNonAlg呈现出随着TP浓度的升高而持续上升的趋势,表明尽管稳态转换存在特定的阈值,但整个富营养化过程中均需加强对营养物浓度的控制.
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