胶州湾沉积物-海水界面营养盐的迁移特征及其影响因素解析

	胶州湾沉积物-海水界面营养盐的迁移特征及其影响因素解析
	汪雅露1,2
学位类型	硕士
导师	袁华茂
	2016-05
学位授予单位	中国科学院大学
学位授予地点	北京
学位专业	环境工程
关键词	胶州湾沉积物-海水界面营养盐交换速率影响因素
其他摘要	本论文分别于2015年7月和2016年1月，乘“创新号”在胶州湾采集无扰动沉积柱和同站位底层海水，采用实验室培养法在原位的温度和溶氧条件下测定了胶州湾沉积物-海水界面硝酸盐（NO₃-N）、亚硝酸盐（NO₂-N）、铵盐（NH₄-N）、磷酸盐（PO₄-P）和硅酸盐（SiO₃-Si）的交换速率。在此基础上，进一步估算了夏、冬两季溶解无机营养盐在胶州湾沉积物-海水界面的交换通量及其对初级生产力的贡献，并探讨了相关环境因子对界面营养盐交换的影响。所得主要结果如下： 1、胶州湾沉积物-海水界面SiO₃-Si均表现为从沉积物向水体迁移，而DIN和PO₄-P在不同季节的迁移方向并不一致，夏季胶州湾沉积物主要表现为水体DIN的源，冬季则整体表现为DIN和PO₄-P的汇。基于估算的胶州湾沉积物-海水界面营养盐的交换通量结果，夏季沉积物释放的N、P可提供维持初级生产力所需N、P的39.3%和14.1%，夏、冬季胶州湾沉积物释放的Si分别可提供维持初级生产力所需Si的15.6%和25.8%。胶州湾多数站位沉积物-海水界面无机氮主要以NO₃-N和NH₄-N的形式进行交换。在夏季，胶州湾多数站位沉积物表现为水体NO₃-N的源，冬季则表现为汇，交换速率为-714~1 560 μmol /(m²·d)。NO₂-N在胶州湾沉积物-海水界面的交换速率普遍较低，夏季沉积物多表现为水体NO₂-N的源，冬季则表现为水体NO₂-N汇，交换速率为-117~941 μmol /(m²·d)。夏季胶州湾沉积物表现为NH₄-N的源，而在冬季多数站位沉积物表现为水体NH₄-N的汇，交换速率在-1 334~26 064 μmol /(m²·d)范围内。夏季沉积物-海水界面PO₄-P的迁移方向并不一致，而冬季沉积物则表现为水体PO₄-P的汇，界面PO₄-P的交换速率为-128~861 μmol /(m²·d)。夏、冬季胶州湾沉积物均表现为水体SiO₃-Si的源，交换速率为43~4 889 μmol/(m²·d)。夏季胶州湾沉积物海水界面间NO₃-N、NO₂-N和NH₄-N的交换通量分别为2.35×10⁸、6.35×10⁷、1.34×10⁹ mmol·d^-1，能提供维持初级生产力所需N的39.3%，PO₄-P的交换通量为3.69×10⁷ mmol·d^-1，能提供维持初级生产力所需P的14.1%。而冬季沉积物则表现为水体NO₃-N、NO₂-N、NH₄-N和PO₄-P的汇，其交换通量分别为-6.39×10⁷、-1.49×10⁷、-1.33×10⁸^、和-2.20×10⁷mmol·d^-1。夏、冬季胶州湾SiO₃-Si的交换通量分别为6.50×10⁸和1.32×10⁸mmol·d^-1，分别提供维持初级生产力所需Si的15.6%和25.8%。 2、夏季胶州湾沉积物中有机质的矿化作用剧烈，对沉积物中各种营养盐的交换均有较为显著的影响。同时，夏季NH₄-N的交换还受底栖藻类的同化作用和吸附-解吸过程调控，而SiO₃-Si的交换受到溶解和扩散过程调控。冬季沉积物中有机质的矿化作用较弱，底栖藻类的同化作用和扩散过程对沉积物-海水界面NO₃-N、PO₄-P和SiO₃-Si的交换影响显著。另外，PO₄-P的交换还受有机质的吸附-解吸作用调控，而SiO₃-Si的交换也受粘土矿物中硅的溶解过程调控。与夏季相似，矿化和吸附-解吸作用依旧是调控冬季胶州湾沉积物-海水界面NH₄-N交换的主要过程。夏季胶州湾沉积物-海水界面NO₃-N的交换速率仅与表层沉积物的含水率、底层NO₃-N浓度和间隙水中NO₃-N浓度相关，而NO₂-N和NH₄-N的交换速率与底质参数、底层水体和间隙水体中对应营养盐的浓度均无显著相关，由主成分回归分析可知，影响夏季NO₃-N、NO₂-N和NH₄-N交换的主要环境因子是表层沉积物的Chl a、TOC、TN、含水率和底层无机氮浓度。由主要影响因子与营养盐交换速率的关系可推知沉积物中有机质的矿化作用和扩散可能是调控NO₃-N交换的主要过程。沉积物中有机质的矿化、底栖藻类的同化作用、沉积物的吸附-解吸和扩散可能是调控夏季胶州湾沉积物-海水界面NH₄-N交换的主要过程。NO₂-N交换与界面NH₄-N交换对环境因子变化的响应较为一致，因此NO₂-N的交换可能主要受硝化作用调控。PO₄-P的交换速率仅与表层沉积物的TOC和C/N相关，而影响其交换的主要环境因子是表层沉积物的Chl a、TOC和TP，有机质的矿化作用可能是影响夏季胶州湾沉积物-海水界面PO₄-P交换的主要过程。夏季胶州湾沉积物-海水界面SiO₃-Si的交换速率与间隙水中SiO₃-Si浓度、底层SiO₃-Si浓度差、表层沉积物的TOC、Chl a、BSi和含水率相关，表层沉积物的Chl a、TOC、BSi、含水率和间隙水中SiO₃-Si浓度是主要影响因子，溶解和扩散过程可能是调控夏季SiO₃-Si交换的主要过程，而有机质的矿化能通过改变沉积物性质促进夏季底层SiO₃-Si的交换。冬季沉积物-海水界面NO₃-N的交换与底质参数、底层水体和间隙水体中NO₃-N浓度均无显著相关，主要影响因子是表层沉积物中的Chl a含量和间隙水中DIN浓度，沉积物-海水界面NO₃-N的交换受底栖藻类的同化作用和扩散共同调控。NO₂-N和NH₄-N的交换速率仅与表层沉积物中Chl a呈一定正相关，表层沉积物的Chl a、粘土含量和D₅₀是影响NH₄-N交换的主要环境因子，底层NH₄-N的交换可能主要受海洋内源自生有机质的降解作用和吸附-解吸过程调控。与夏季一样，冬季胶州湾沉积物-海水界面NO₂-N交换与界面NH₄-N交换对环境因子变化的响应较为一致，因此NO₂-N的交换可能受硝化作用调控。PO₄-P的交换速率仅与表层TOC相关，主要影响因子有表层沉积物中的Chl a、TOC、含水率、底层PO₄-P浓度和间隙水PO₄-P浓度，有机质对PO₄-P的吸附-解吸作用、底栖生物的同化作用和扩散可能是调控冬季底层PO₄-P交换的主要过程。SiO₃-Si的交换与间隙水中SiO₃-Si浓度和表层沉积物中BSi含量相关，主要影响因子是表层沉积物中的Chl a含量和间隙水中SiO₃-Si浓度，主要受底栖藻类的同化作用、溶解和扩散过程调控。 ; Intatct sediment cores and the bottom seawater in the corresponding stations in Jiaozhou Bay was collected in July 2015 and Jaunary 2016, and the benthic exchange rates of NO₃-N, NO₂-N, NH₄-N, PO₄-P and SiO₃-Si were measured by intact sediment cores incubation. Further, the benthic fluxes and its contributions to the primary productivity were estimated, and the impacts of relevant environmental factors on the benthic transport were discussed. The main results are as follows: 1、SiO₃-Si was directed out of sediment to the overlying water in Jiaozhou Bay，while the exchange of NO₃-N、NO₂-N、NH₄-N and PO₄-P varied with season. Sediment was an important source of DIN and PO₄-P in summer, DIN and PO₄-P transferred from water column to sediment in winter. Based on the exchange rates and the proportion of different sediments, the exchange fluxes of dissolved nutrient were estimated. The result showed that sediment could provide 39.3% and 14.1% of N and P required by the primary productivity respectively. Sediment was always the source of SiO₃-Si, providing 15.6% SiO₃-Si required for primary productivity in summer, and 25.8% SiO₃-Si in winter. The exchange of dissolved inorganic nitrogen at sediment-water interface in Jiaozhou Bay was mainly in forms of NO₃-N and NH₄-N. The exchange of NO₃-N and NH₄-N was in direction from sediment to overlying water in summer, while it became uncertain in winter. The exchange rates ranged from -714 to 1 560 μmol /(m²·d) for NO₃-N and from -1 334 to 26 064 μmol /(m²·d) for NH₄-N. The exchange rates of NO₂-N and PO₄-P varies in summer and winter, ranging from -117 to 941 μmol /(m²·d) for NO₂-N and from -128 to 861 μmol /(m²·d) for PO₄-P. The exchange rates of SiO₃-Si were in the direction from sediment to overlying water, ranging from 43 to 4 889 μmol/(m²·d). In summer, sediment was an important source of NO₃-N、NO₂-N and NH₄-N,the fluxes at the sediment-water interface were 2.35×10⁸、6.35×10⁷ and 1.34×10⁹ mmol·d^-1 respectively, providing 39.3% N required for primary productivity. In winter, however, NO₃-N、NO₂-N and NH₄-N transferred from water to sediment, and fluxes were -6.39×10⁷、-1.49×10⁷ and -1.33×10⁸ mmol·d^-1，respectively. PO₄-P transferred from water to sediment with fluxes of 3.69×10⁷ mmol·d^-1 in summer， providing 14.1% P required for primary productivity. In winter, the transferring direction was reversed, and the flux was -2.20×10⁷mmol·d^-1. Sediment was always the source of SiO₃-Si, and its fluxes were 6.50×10⁸ mmol·d^-1 in summer and 1.32×10⁸mmol·d^-1 in winter，providing 15.6% and 25.8% Si required for primary productivity respectively. 2、The most important environmental factors and processes controlling the nutrient exchange rates varied with season and the type of nutrients. In summer, mineralization was an controlling processes for all kinds of nutrients. The exchange of NH₄-N in summer was also controlled by assimilation and adsorption-desorption, while the exchange of SiO₃-Si was mainly controlled by dissolution and diffusion. In winter, mineralization became weak and the exchange of NO₃-N, PO₄-P and SiO₃-Si were mainly influenced by assimilation and diffusion. The exchange of PO₄-P in winter was also influenced by the process of adsorption-desorption caused by organic matter mattered, and the exchange of SiO₃-Si in winter was also influenced by dissolution process. Same as summer, the exchange of NH₄-N in winter was probably significantly influenced by mineralization and adsorption-desorption at sediment-water interface. The exchange rates of NO₃-N were correlated to water ratio of surface sediment and bottom-water NO₃-N concentration and pore-water NO₃-N concentration, while the exchange rates of NO₂-N and NH₄-N were not correlated to any factor of surface sediment or the concentration of corresponding nutrient. Based on principal component regression analysis, the result revealed that total organic carbon (TOC), chlorophyll a (Chl a), total nitrogen (TN), water ratio and concentration of dissolved nitrogen (DIN) were the the most important factors influencing the exchange of NO₃-N、NO₂-N and NH₄-N. As a result, mineralization and diffusion might be the controlling processes for the exchange of NO₃-N. Mineralization, assimilation, adsorption-desorption and diffusion, however, might be the most controlling processes for the exchange of NH₄-N in summer. Exchange of NO₂-N varied in the same pattern with NH₄-N in summer, so that nitrification may be the key process controlling the exchange of NO₂-N. The exchange rates of PO₄-P in summer were positively related to TOC and negatively correlated to C/N in surface sediment, and the major factors influcing the exchange of PO₄-P were Chl a、TOC and TP. As a result, mineralization might be the most controlling processes for the exchange of PO₄-P in summer. The exchange rates of SiO₃-Si in summer were significantly related to TOC and Chl a in surface sediment, and also positively related to biogenic silicate (BSi), content of clay, water ratio, SiO₃-Si concentration in pore water and the concentration difference of SiO₃-Si at the interface, and TOC, Chl a, biogenic silicate (BSi), content of clay, water ratio of surface sediment and SiO₃-Si concentration in pore water were the most important relevant factors. As a result, the exchange of SiO₃-Si at sediment-water interface in summer was a consequence of dissolution-diffusion process which was dominantly controlled by biological activity. The exchange rates of NO₃-N in winter were not correlated to any factor of surface sediment or the concentration of corresponding nutrient. Considering that Chl- a in the surface sediment and the DIN concentration in pore water were the most important factors, assimilation and diffusion might be the controlling processes for the exchange of NO₃-N. The exchange rates of NO₂-N in winter were only related to Chl- a in the surface sediment and the mechanism was not clear yet. The exchange rates of NH₄-N in winter were positively related to Chl a, and Chl a in surface sediment, content of clay and medium diameter (D₅₀) had significant effects on the exchange of NH₄-N , so the degradation of marine endogenous organic matter and adsorption- desorption at sediment-water interface might be the controlling processes for the exchange of NH₄-N in winter. The exchange rates of PO₄-P in winter were only related to TOC in surface sediment, and Chl a, TOC, water ratio and PO₄-P concentration in bottom water and pore water were the major relevant factors influencing the exchange of PO₄-P, so assimilation, dilution and adsorption-desorption caused by the organic matter might be the controlling processes for the exchange of PO₄-P in winter. The exchange rates of SiO₃-Si in winter were significantly positively related to BSi in surface sediment and SiO₃-Si concentration in pore water, and the Chl a in surface sediment and pore-water SiO₃-Si concentration had major effects on the exchange of SiO₃-Si at sediment-water interface, so the exchange of SiO₃-Si in winter was controlled by assimilation, diffusion and dissolution.
学科领域	地球化学 ; 海洋科学
语种	中文
文献类型	学位论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/112565
专题	海洋生态与环境科学重点实验室
作者单位	1.中国科学院海洋生态与环境重点实验室 2.中国科学院大学
推荐引用方式 GB/T 7714	汪雅露. 胶州湾沉积物-海水界面营养盐的迁移特征及其影响因素解析[D]. 北京. 中国科学院大学,2016.

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