【摘要】：磷是生物生長的必需營養(yǎng)鹽,但目前磷循環(huán)的示蹤手段仍十分有限。磷酸鹽的氧同位素只有在生物或酶的作用下才會和外界水發(fā)生氧交換后產(chǎn)生分餾,因此其既可以示蹤磷的源區(qū),也具有指示生物對磷利用程度的潛力。目前磷酸鹽氧同位素已被廣泛用來示蹤開闊大洋、河口及土壤中的磷循環(huán)。河口磷循環(huán)影響著河流向海洋的磷輸入。以往相關(guān)研究以各種形態(tài)磷含量的分布特征為主,對于磷的源區(qū)及各種形態(tài)磷間的轉(zhuǎn)化了解甚少。 本研究建立了河口底層沉積物中4種無機(jī)形態(tài)磷酸鹽氧同位素的測定方法。利用KH2P04溶液和國際磷礦標(biāo)準(zhǔn)(NBS-120c)對沉積物中磷的提取、分離和純化方法進(jìn)行驗(yàn)證,結(jié)果表明處理流程可以獲得純的Ag3PO4,且不會造成明顯的磷酸鹽氧同位素分餾。利用一個石獅近岸的天然沉積物樣品進(jìn)行平行性測定,結(jié)果顯示方法的精密度良好,且不同形態(tài)磷酸鹽具有不同的氧同位素值。 對2013年10月九龍江河口區(qū)表層水溶解磷酸鹽的氧同位素進(jìn)行研究,發(fā)現(xiàn)河流端和海水端水體中磷酸鹽的氧同位素接近平衡分餾值。根據(jù)磷酸鹽保持著源區(qū)的氧同位素值,可以判斷出龍海市區(qū)(A5站)、南溪口(A8站)、廈門第一碼頭(X2站)和滸茂洲岔道口(X7站)對九龍江河口存在的磷輸入。2013年12月河口周圍地下水中溶解磷酸鹽的氧同位素接近平衡分餾值。而2013年7月暴雨時河口表層水溶解磷酸鹽的氧同位素遠(yuǎn)高于平衡分餾值。這些結(jié)果顯示九龍江河口水體溶解磷酸鹽氧同位素對環(huán)境具有靈敏的響應(yīng)。 2013年7月暴雨后(10天)九龍江河口區(qū)表層沉積物具有高的磷含量,尤其有機(jī)磷高達(dá)6.6～10.2μmol/g.弱吸附態(tài)和鐵氧化物結(jié)合態(tài)磷酸鹽的氧同位素和相應(yīng)水體溶解態(tài)磷酸鹽接近,都呈現(xiàn)出由河流端向海端增高的特點(diǎn),顯示其來自于河口區(qū)水體的特征。自生磷灰石和碎屑磷灰石的磷酸鹽氧同位素接近,都明顯低于相應(yīng)站位水體溶解態(tài)磷酸鹽,由河流端向海端變化不大,顯示其陸源特征。
[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.
【學(xué)位授予單位】：廈門大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：P734.2

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 陳錦芳;曹建平;黃奕普;;廈門沿岸地區(qū)大氣降水中氫、氧穩(wěn)定同位素組成及其影響因素[J];海洋學(xué)研究;2010年01期

2 陳志剛;黃奕普;劉廣山;蔡毅華;盧陽陽;劉潤;;磷酸鹽氧同位素組成的測定方法及分餾機(jī)理研究進(jìn)展[J];地球科學(xué)進(jìn)展;2010年10期

3 于宇;宋金明;李學(xué)剛;袁華茂;李寧;段麗琴;;長江口海域表層沉積物中磷的形態(tài)分布及環(huán)境意義[J];地球科學(xué)進(jìn)展;2011年08期

4 盧陽陽;鄭珍珍;尹希杰;陳志剛;蔡毅華;劉廣山;黃奕普;;海水溶解磷酸鹽氧同位素組成的測定[J];地球?qū)W報(bào);2012年06期

5 侯立軍;陸健健;劉敏;許世遠(yuǎn);;長江口沙洲表層沉積物磷的賦存形態(tài)及生物有效性[J];環(huán)境科學(xué)學(xué)報(bào);2006年03期

6 陳水土;九龍江口、廈門西海域無機(jī)氮與磷的關(guān)系[J];海洋通報(bào);1993年05期

7 李學(xué)剛,宋金明,李寧,袁華茂,高學(xué)魯;膠州灣沉積物中氮與磷的來源及其生物地球化學(xué)特征[J];海洋與湖沼;2005年06期

8 岳維忠;黃小平;孫翠慈;;珠江口表層沉積物中氮、磷的形態(tài)分布特征及污染評價(jià)[J];海洋與湖沼;2007年02期

9 張遠(yuǎn)輝,王偉強(qiáng),黃自強(qiáng);九龍江口鹽度鋒面及其營養(yǎng)鹽的化學(xué)行為[J];海洋環(huán)境科學(xué);1999年04期

10 ;Distribution,fluxes and decadal changes of nutrients in the Jiulong River Estuary,Southwest Taiwan Strait[J];Chinese Science Bulletin;2012年18期

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