| 南亚热带水库消落带土壤主要金属元素流失及其对沉积物磷释放的影响 |
| Loss of Primary Metal Elements from Soil and Effect on Phosphorus Release from Sediments in the Water-fluctuation Zone of Subtropical Reservoirs, China |
| 投稿时间：2023-06-26 修订日期：2023-09-12 |
| DOI：10.15928/j.1674-3075.202306260171 |
| 中文关键词:土壤 沉积物 磷 铁 南亚热带水库 |
| 英文关键词:soil sediment phosphorus iron subtropical reservoirs |
| 基金项目: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) |
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| 中文摘要: |
| 磷从陆地向水体迁移以及沉积物内源磷的释放是水体富营养化的主要过程。南亚热带地区土壤富含铁,铁结合态磷是该地区土壤和沉积物中磷的重要组成部分,铁与磷的相互关系可能在该地区水体富营养化中扮演关键角色。本文比较了中国南亚热带地区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)含量或浓度。结果显示：沉积物与消落带土壤中各元素含量的比值依次为Mn>P>Fe>1>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总磷与铁含量显著正相关(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。暗示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。 |
| 英文摘要: |
| 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 sediments. 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 eutrophic reservoirs, 18 mesotrophic reservoirs and 3 oligotrophic reservoirs, and we compared the concentrations 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 subtropical 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 followed 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 sediment 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 content 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 sediments of subtropical reservoirs is approximately 0.6mg/g. When the ratio Fe:P>70, the P concentration in water was < 20 μg/L, and the reservoir water was mesotrophic, indicating that Fe in the surface sediments adsorbs P and inhibits release, so the sediment acts as a sink for P. When the ratio Fe: P<70, there was no significant correlation between TP and Fe, but the P concentration in water was negatively correlated with the Fe:P ratio in sediments (P<0.05), indicating that Fe:P adsorption by sediments was near saturation. This suggests that an Fe:P ratio of 70 is the threshold for sediment P conversion from sink to source in subtropical reservoirs. |
| 赵孟绪,唐鹊辉,王灵紫,胡克武,吴 杰,曹家瑶,彭 亮.2023.南亚热带水库消落带土壤主要金属元素流失及其对沉积物磷释放的影响[J].水生态学杂志,44(6):88-95. |
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