九龙江河口溶解磷酸盐及沉积物中不同形态磷酸盐的氧同位素分布特征及意义
发布时间：2018-09-09 16:41
【摘要】：磷是生物生长的必需营养盐,但目前磷循环的示踪手段仍十分有限。磷酸盐的氧同位素只有在生物或酶的作用下才会和外界水发生氧交换后产生分馏,因此其既可以示踪磷的源区,也具有指示生物对磷利用程度的潜力。目前磷酸盐氧同位素已被广泛用来示踪开阔大洋、河口及土壤中的磷循环。河口磷循环影响着河流向海洋的磷输入。以往相关研究以各种形态磷含量的分布特征为主,对于磷的源区及各种形态磷间的转化了解甚少。 本研究建立了河口底层沉积物中4种无机形态磷酸盐氧同位素的测定方法。利用KH2P04溶液和国际磷矿标准(NBS-120c)对沉积物中磷的提取、分离和纯化方法进行验证,结果表明处理流程可以获得纯的Ag3PO4,且不会造成明显的磷酸盐氧同位素分馏。利用一个石狮近岸的天然沉积物样品进行平行性测定,结果显示方法的精密度良好,且不同形态磷酸盐具有不同的氧同位素值。 对2013年10月九龙江河口区表层水溶解磷酸盐的氧同位素进行研究,发现河流端和海水端水体中磷酸盐的氧同位素接近平衡分馏值。根据磷酸盐保持着源区的氧同位素值,可以判断出龙海市区(A5站)、南溪口(A8站)、厦门第一码头(X2站)和浒茂洲岔道口(X7站)对九龙江河口存在的磷输入。2013年12月河口周围地下水中溶解磷酸盐的氧同位素接近平衡分馏值。而2013年7月暴雨时河口表层水溶解磷酸盐的氧同位素远高于平衡分馏值。这些结果显示九龙江河口水体溶解磷酸盐氧同位素对环境具有灵敏的响应。 2013年7月暴雨后(10天)九龙江河口区表层沉积物具有高的磷含量,尤其有机磷高达6.6～10.2μmol/g.弱吸附态和铁氧化物结合态磷酸盐的氧同位素和相应水体溶解态磷酸盐接近,都呈现出由河流端向海端增高的特点,显示其来自于河口区水体的特征。自生磷灰石和碎屑磷灰石的磷酸盐氧同位素接近,都明显低于相应站位水体溶解态磷酸盐,由河流端向海端变化不大,显示其陆源特征。
[Abstract]:Phosphorus is an essential nutrient for biological growth, but the tracing method of phosphorus cycle is still very limited. The oxygen isotopes of phosphate can only be separated by oxygen exchange with external water under the action of biological or enzyme, so they can trace the source region of phosphorus and have the potential to indicate the extent of phosphorus utilization by organisms. Phosphate oxygen isotopes have been widely used to trace phosphorus cycling in open oceans, estuaries and soils. Estuarine phosphorus cycle affects the flow of phosphorus from rivers to the ocean. Previous studies focused on the distribution characteristics of various forms of phosphorus, but little was known about the source areas of phosphorus and the transformation of various forms of phosphorus. In this study, a method for the determination of four inorganic phosphate oxygen isotopes in estuarine sediments was established. The extraction, separation and purification of phosphorus in sediments were verified by KH2P04 solution and International Phosphate Rock Standard (NBS-120c). The results showed that pure Ag3PO4, could be obtained by the treatment process without significant phosphate oxygen isotope fractionation. The parallelism of a natural sediment sample from Shishi inshore shows that the precision of the method is good and different phosphate species have different oxygen isotopic values. The oxygen isotope of phosphate dissolved in surface water of Jiulong River estuary in October 2013 was studied. It was found that the oxygen isotope of phosphate in river and seawater was close to equilibrium fractionation value. According to the oxygen isotopic values of the source region maintained by the phosphate, The phosphorus input of Longhai District (A5 Station), Nanxikou Station (A8 Station), Xiamen No. 1 Wharf (X2 Station) and Humaozhou Branch Road mouth (X7 Station) to Jiulong River Estuary can be judged. Oxygen colocation of dissolved phosphate in groundwater around estuary in December 2013 The element is close to the equilibrium fractionation value. The oxygen isotope of phosphate dissolved in the estuarine surface water was much higher than the equilibrium fractionation value during the rainstorm in July 2013. These results show that dissolved phosphate oxygen isotopes in Jiulong River Estuary are sensitive to the environment. The surface sediments of Jiulong River Estuary area have high phosphorus content, especially organic phosphorus, up to 6.6 渭 mol/g. (10.2 渭 mol/g.) after heavy rain in July 2013 (10 days). The oxygen isotopes of weakly adsorbed phosphate and iron-oxide bound phosphate are close to the dissolved phosphate in the corresponding water body, showing the characteristics of rising from the end of the river to the sea end, indicating that they come from the water body in the estuary area. The phosphate oxygen isotopes of authigenic apatite and detrital apatite are close and are obviously lower than the dissolved phosphate of the corresponding station water body.
【学位授予单位】：厦门大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P734.2
本文编号：2232979
[Abstract]:Phosphorus is an essential nutrient for biological growth, but the tracing method of phosphorus cycle is still very limited. The oxygen isotopes of phosphate can only be separated by oxygen exchange with external water under the action of biological or enzyme, so they can trace the source region of phosphorus and have the potential to indicate the extent of phosphorus utilization by organisms. Phosphate oxygen isotopes have been widely used to trace phosphorus cycling in open oceans, estuaries and soils. Estuarine phosphorus cycle affects the flow of phosphorus from rivers to the ocean. Previous studies focused on the distribution characteristics of various forms of phosphorus, but little was known about the source areas of phosphorus and the transformation of various forms of phosphorus. In this study, a method for the determination of four inorganic phosphate oxygen isotopes in estuarine sediments was established. The extraction, separation and purification of phosphorus in sediments were verified by KH2P04 solution and International Phosphate Rock Standard (NBS-120c). The results showed that pure Ag3PO4, could be obtained by the treatment process without significant phosphate oxygen isotope fractionation. The parallelism of a natural sediment sample from Shishi inshore shows that the precision of the method is good and different phosphate species have different oxygen isotopic values. The oxygen isotope of phosphate dissolved in surface water of Jiulong River estuary in October 2013 was studied. It was found that the oxygen isotope of phosphate in river and seawater was close to equilibrium fractionation value. According to the oxygen isotopic values of the source region maintained by the phosphate, The phosphorus input of Longhai District (A5 Station), Nanxikou Station (A8 Station), Xiamen No. 1 Wharf (X2 Station) and Humaozhou Branch Road mouth (X7 Station) to Jiulong River Estuary can be judged. Oxygen colocation of dissolved phosphate in groundwater around estuary in December 2013 The element is close to the equilibrium fractionation value. The oxygen isotope of phosphate dissolved in the estuarine surface water was much higher than the equilibrium fractionation value during the rainstorm in July 2013. These results show that dissolved phosphate oxygen isotopes in Jiulong River Estuary are sensitive to the environment. The surface sediments of Jiulong River Estuary area have high phosphorus content, especially organic phosphorus, up to 6.6 渭 mol/g. (10.2 渭 mol/g.) after heavy rain in July 2013 (10 days). The oxygen isotopes of weakly adsorbed phosphate and iron-oxide bound phosphate are close to the dissolved phosphate in the corresponding water body, showing the characteristics of rising from the end of the river to the sea end, indicating that they come from the water body in the estuary area. The phosphate oxygen isotopes of authigenic apatite and detrital apatite are close and are obviously lower than the dissolved phosphate of the corresponding station water body.
【学位授予单位】：厦门大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P734.2
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