摘要
比较中国南亚热带地区31座大型水库消落带裸露土壤、表层沉积物和水体中的磷和主要金属元素(Al、Ca、Fe和Mn)含量,探讨水相磷与沉积物固相磷和铁之间的关系,为中国南亚热带水库沉积物内源磷释放对水库富营养化的贡献提供准确预测。结果显示:由南向北,水库消落带土壤铁含量逐渐下降,土壤钙含量逐渐上升;沉积物与消落带土壤中各元素含量的比值依次为Mn>P>Fe>Al>Ca,与土壤铁和锰高的流失率相比,铝和钙基本无流失作用,铁和锰从流域土壤向水体和沉积物迁移可能是华南地区水体铁锰超标的重要原因;水库消落带土壤和表层沉积物中总磷与铁含量均显著正相关(P<0.05),且沉积物铁结合态磷含量占总磷的百分比显著高于土壤(P<0.05),表明磷主要与流域土壤中的铁结合并共同迁移、沉降,最终汇入沉积物中。当水库表层沉积物总磷含量达0.6mg/g时,沉积物总磷含量与铁含量相关,推测南亚热带水库沉积物磷的饱和滞留量可能在0.6mg/g左右。当Fe:P>70时,水体磷浓度基本低于20μg/L,水库处于中营养状态,表明表层沉积物中的铁能吸附水体磷并抑制磷释放,此时沉积物是磷的“汇”。当Fe:P<70,总磷含量与铁含量之间无显著相关性,水体磷浓度与沉积物铁磷比显著负相关(P<0.05),表明这些水库沉积物中铁对磷的吸附可能已开始饱和。沉积物铁磷质量比为70可能是南亚热带水库沉积物开始由磷汇向磷源转化的关键阈值。
The migration of phosphorus(P)from land to water and the release of P from sediments are the primary causes of eutrophication.The soil of China's subtropical region is rich in iron(Fe),and iron-bound phosphorus(Fe-P),an important component of the phosphorus in soils and sedi-ments.Thus,the relationship between Fe and P may play a key role in reservoir eutrophication in this region.For this study,31 large reservoirs in subtropical China were selected,including 10 eutro-phic reservoirs,18 mesotrophic reservoirs and 3 oligotrophic reservoirs,and we compared the concen-trations of P and major metal elements(Al,Ca,Fe and Mn)in the water,surface sediments and soils of water-fluctuation zones in these reservoirs.The distribution characteristics and influencing factors were then analyzed based on the results and the relationships between P concentration in water,and P content of iron in the sediments was characterized.Our objective was to allow accurate predication of the contribution of endogenous P release from sediments to the eutrophication of reservoirs in sub-tropical China.Results show that soil iron content decreased and soil calcium content increased from south to north.The ratio of sediment content to fluctuation zone soil content for each element fol-lowed the order Mn>P>Fe>Al>Ca.The loss rate of Fe and Mn from soil was high,while there was almost no loss of aluminum and calcium.The migration of Fe and Mn from soil to water and sedi-ment may be an important reason for the accumulation and excess of Fe and Mn in the waters of south China.There was a significant positive correlation between total phosphorus(TP)and Fe con-tent in both soil and surface sediments(P<0.05),and the percentage of Fe-P content in sediment was significantly higher than that in soil(P<0.05).We found that P was mainly combined with Fe in the soil,transferred together to water and then settled to the sediment.TP was related to the iron content of surface sediments when TP reached 0.6mg/g,suggesting that the saturation retention of P in sedi
作者
赵孟绪
唐鹊辉
王灵紫
胡克武
吴杰
曹家瑶
彭亮
ZHAO Meng-xu;TANG Que-hui;WANG Ling-zi;HU Ke-wu;WU Jie;CAO Jia-yao;PENG Liang(Hydrological Bureau of Guangdong Province,Guangzhou Hydrology Branch,Guangzhou 510140,P.R.China;Department of Ecology,Jinan University,Guangzhou 510632,P.R.China;Zhuhai Water Environment Holdings Group LTD,Zhuhai 519070,P.R.China)
出处
《水生态学杂志》
CSCD
北大核心
2023年第6期88-95,共8页
Journal of Hydroecology
基金
生态红土原位覆盖/钝化处置水库底泥的技术开发(40122045)
蓝藻水华应急处置技术示范研究(40120164)。
关键词
土壤
沉积物
磷
铁
南亚热带水库
soil
sediment
phosphorus
iron
subtropical reservoirs
