南大洋普里兹湾生物硅的生产、溶解、沉降及其保存机制研究
发布时间：2018-07-15 17:00
【摘要】：南大洋海冰区在全球变化中占有极为重要的地位,在碳等生源要素在全球生物地球化学循环中扮演着举足轻重的角色。在南大洋,硅藻是生态系统中主要的生产者,是生物泵的重要组成部分,输送到深海的有机碳通量一半以上是由硅藻贡献的。因此进行南大洋硅循环中关键的生物地球化学过程研究,有助于我们更好地理解南大洋碳循环的时空变化。普里兹湾是除威德尔海、罗斯海之外,南大洋印度洋扇形区中最大海湾,是典型的边缘海冰区。然而相对于研究人员在威德尔海、罗斯海海域所开展的相关研究,有关普里兹湾生物硅关键过程的认知还是非常匮乏、非常缺乏系统性。针对普里兹湾生物硅研究的现状,本论文以普里兹湾水体以及沉积物中生物硅为重点研究对象,以2002-2013年间获取的中国南极科学考察相关现场数据以及实验模拟数据为基础,系统研究南大洋普里兹湾生物硅循环的关键过程,进而验证并量化生物硅的生产、输出以及再循环效率,探讨普里兹湾生物硅的保存机制。本论文主要研究内容和主要研究结果如下： 1.普里兹湾表层水体中生物硅的生产及其在表层水体中的输出过程。 (1)在2013年夏季,普里兹湾海域表层PBSi的含量在0.38-8.62μmol/dm3之间变化,分布趋势呈现67°S以南湾内含量明显高于67°S以北的湾外海域,与表层Chla的分布基本吻合。垂向分布上PBSi同样与Chla的分布非常相近,呈现明显的50m层以内含量高于50m以下水体含量的趋势。与以往航次的数据相比,PBSi的含量存在一定的年际变化,但是在普里兹湾的分布情况基本相似。 (2)在普里兹湾生物因子是PBSi含量分布的主控因子。根据不同年份PBSi的平均含量与Chla平均含量数据显示,普里兹湾湾内湾外海域表层PBSi平均含量与Chla的平均含量的年际变化非常一致。气候变化会对普里兹湾的海冰变化产生一定的影响,而相应的普里兹湾浮游植物在数量种群结构上也会随海冰变化产生一定的改变,这一结果对PBSi的含量与分布也产生相应的影响。 (3)普里兹湾湾内表层水体中Si/C平均比值为0.21与报道中的南大洋的平均比值非常相近。随着水层深度的增加湾外以及湾内水体中Si/C比值都发生了降低,表明在普里兹湾上层水体生物硅和有机碳输出过程存在退耦关系,有机碳的降解转化过程不及生物硅的溶出过程,从而使得50m水体PBSi的输出低于POC,因此最终导致Si/C比值降低。 (4)利用硅酸盐的季节性消耗量估算出普里兹湾上表层水体中硅酸盐的消耗速率,即生物硅的生产速率,获取的结果为：14.54mmol/m2/d；利用Si/C比值以及现场实测初级生产力数据估算出的生物硅生产速率则为20.20mmol/m2/d。与南大洋其他海域相比属于较高的生物硅生产水平。利用现场硅稳定同位素培养实验数据结合水体中累积的生物硅含量变化获得的结果表明,在普里兹湾湾内表层水体中生产的生物硅89%由表层输出,而在50m水体向下输送至200m水体中的生物硅为36%,表明生物硅在表层生产后仅有少部分发生溶出,而在随后的向更深层的200m水体输送过程中已经发生了大量的溶出,占表层生产的64%。 2.普里兹湾中深层水体中生物硅的垂直输送过程。 (1)普里兹湾湾内冰间湖区域沉降颗粒物主要以硅藻聚合体为主,其间也夹杂着一些未聚合的硅藻单体。而普里兹湾湾外沉降颗粒物除了硅藻聚合体之外,在通量峰值的夏季住囊类聚集体也不容忽视。普里兹湾湾内与湾外区域沉降颗粒类型存在一定的差异,反映了普里兹湾不同区域上层水体颗粒物来源以及相关生物地球化学过程的差异。 (2)根据我们获取的三个调查年份的颗粒物组成数据显示,生源组分是颗粒物的主要组成。在颗粒物生源组分中,做出主要贡献的是生物硅通量。生物硅有机碳等生源物质的通量主要受上层水体浮游植物生长的影响,呈现明显的季节性变化。通量的峰值均出现在夏季浮游植物旺发的1-2月份之间,最低值出现在冬季的5-7月份。在夏季相同时期,湾内冰间湖区域生物硅通量值明显高于湾外深海海域生物硅通量值。 (3)气候变化对普里兹湾表层水体浮游植物生长的影响,在深层水体中的生源物质通量也有相应的响应。在2009/2010年由于受到厄尔尼诺影响,在12月份普里兹湾的浮游植物旺发已经达到最大并持续到一月份才开始减弱,而2010/2011年夏季则受到拉尼娜事件影响使得捕获器布放的冰间湖区域浮游植物生长明显低于2009/2010年的同期。由此导致2009/2010夏季以及2010/2011夏季生物硅的通量呈现明显的年际差异。 (4)2009/2010年以及2010/2011年夏季普里兹湾深层水中颗粒物Si/C比值分别为2.5和1.8,明显大于200m水层中Si/C的比值,表明颗粒物由上层水体输出后在随后向深层水体输送的过程中,有机碳发生再矿化的程度远大于生物硅的溶出,这主要是由于浮游植物由表层的输出后逐渐老化直至死亡,大部分硅藻仅剩下空壳,此时有机碳发生快速的降解,从而导致深层水体中Si：C比值明显的提高。 (5)根据普里兹湾湾内深层水体中(480m)生物硅的通量与表层生物硅的生产量比值估算出普里兹湾水体中生物硅的保存效率,2009/2010年夏季为26%,2010/2011年夏季为24%,二者平均为25%,表明表层生产的生物硅在沉降到沉积物之前已经有75%的生物硅发生溶出。由于普里兹湾湾内表层水体中生产的生物硅在50-200m以内的水体以及发生了大规模的溶出(64%溶出),在200m以下水体输送过程中虽然溶出继续,但是其程度明显小于上层水体。 3.普里兹湾表层沉积物中生物硅再循环过程。 (1)普里兹湾表层沉积物中生物硅的含量在4.89-75.32%之间变化,在纬向空间分布上,生物硅含量呈现明显的67°S以南湾内陆架区湾内冰缘区67°S以北的湾外深海区的分布形式。普里兹湾不同纬度柱状沉积物中生物硅的分布结果表明在67°S以北的湾外柱状沉积物中生物硅的分布趋势与湾内有一定的差别。在湾外66.50S沉积物中总体上讲生物硅含量随深度的增加逐渐升高,且含量波动不大,而在湾内67.5°S柱状沉积物中,生物硅含量波动明显,总体上是随深度增加是降低的趋势。 (2)表层沉积物中生物硅和有机碳呈现较为相似的空间分布,Si/C元素摩尔比值Si/C元素摩尔比值在4.60-18.48之间变化,远远大于深层水体以及200m水体颗粒物中Si/C比值。有机碳的垂向分布与生物硅有一定的差异,表明二者在沉积埋葬过程中所经历的物理、化学及生物反应的差异。 (3)普里兹湾沉积物间隙水中DSi的含量变化范围较大,其中表层间隙水中DSi的含量在118.15-552.00μmol/dm3之间变化,平均为352.43μmol/dm3,最高值出现在湾内陆架区,最低值出现在湾外陆坡与陆架交界处站位。大部分站位沉积物间隙水中DSi均呈现类似的垂向分布,即在靠近沉积物-水界面DSi有明显的浓度梯度,由上覆水中的平均含量75.19μmol/dm3,升高到表层间隙水中的352.43μmol/dm3,而在福拉姆浅滩区的站位上覆水硅酸盐含量与表层间隙水含量相差不大。(4)在普里兹湾沉积物海水界面之下,随深度增加DSi含量分布呈指数增加,随后逐渐达到一个趋于稳定的渐进浓度Cd,与沉积物中生物硅的垂向分布呈现相反变化趋势,表明在普里兹湾生物硅逐渐埋葬的过程中快速溶出是主要过程,使得间隙水中硅酸盐快速富集。普里兹湾间隙水中硅酸盐Cd的高值出现在湾内陆架区的67.5°S和68°S的站位,分别为644.01、65126μmol/dm3,而湾内冰缘区附近站位的Cd明显低于陆架区。最低值出现在湾口福拉姆浅滩区66.86°S站位的Cd值为47284μmol/dm3,。 (5)利用一维模型法估算得到在普里兹湾沉积物中硅酸盐的释放通量,结果表明在普里兹湾湾内,沉积物中硅酸的释放通量分布呈现由湾口陆坡区向湾内降低的趋势,通量最高值115mmol/m2/d出现在靠近福拉姆浅滩的湾口区站位,最低值出现在湾内陆架区67.5°S站位释放通量为0.30mmol/m2/d。现场实验法获取的陆架区站位硅酸盐释放速率最低为0.45mmol/m2/d,而在冰缘区和湾口区的培养实验获取的释放速率分别为063mmol/m2/d和0.60mmol/m2/d。总体上讲与模型法估算的相应站位通量值变化范围相近,DSi的扩散通量主要来源于沉积物上层5cm以内的生物硅的溶出。4.普里兹湾表层沉积物中生物硅的溶出与保存机制。 (1)利用batch实验获取沉积物生物硅溶解性质的研究结果显示,实验室条件下陆架区和冰缘区表层沉积物中生物硅的溶解度分别为1936μmol/dm3,1540μmol/dm3。在冰缘区站位5cm下沉积物中生物硅的溶出平衡浓度明显低于5cm以上的沉积物。而在陆架区站位除在5cm内有较明显的降低外,在5-20cm之间生物硅的溶解度随深度的增加相对与上层变化较小。对比普里兹湾沉积物间隙水中DSi的垂向分布研究结果,间隙水Cd的平均值明显低于实验室获取的溶解度。 (2)根据Batch实验数据计算普里兹湾陆架区和冰缘区表层沉积物中生物硅的实验室溶出速率分别为201μmol/h/g,1.09μmol/h/g。在不同区域0-5cm的沉积物范围内,生物硅溶出解速率随深度增加明显降低,5cm以下沉积物中则基本变化不大,总体上讲在实验室模拟实验中普里兹湾沉积物中表层沉积物生物硅的溶出速率要高于深层沉积物,表明在沉积物表层(0-4.5cm)生物硅的溶出要明显快于深层沉积物。 (3)在普里兹湾沉积物中生物硅的埋葬通量在0.09-2.06mol/m2/a之间,最高埋葬量出现在湾内陆架区的67.5-680S的区域,最低值出现在湾口福拉姆浅滩区。在普里兹湾生物硅保存效率存在很明显的空间差异,在湾口浅滩区生物硅的保存效率仅为18%,远远低于湾内陆架区的94%以及冰缘区的83%。普里兹湾沉积物中生物硅的沉积通量平均值与南大洋其他海域相比略低,但是由于再循环通量最低,因此在普里兹湾沉降到海底的生物硅在沉积物的79%埋葬效率明显高于其他研究区域。这些数据也再次证明在南大洋沉积物中生物硅的保存具有明显的空间差异。 (4)普里兹湾沉积物中生物硅的最终保存不仅与上层水体硅藻的初级生产有关,同时还受到沉降及埋葬过程中的保存机制控制。在普里兹湾沉积速率以及生物扰动对普里兹湾生物硅的早期成岩过程以及最终保存会有实质性及潜在性的影响,此外陆架区沉积物中A1与硅藻壳体的作用可能已经不仅仅是在表面的吸附,而是嵌入到了硅藻骨架中,从而使得生物硅的溶解动力学性质和热力学性质均发生了改变。在普里兹湾沉积物中生物硅的保存是以上三种因素综合作用的结果。 5.普里兹湾生物硅收支平衡估算。 (1)在普里兹湾上层水体生物硅年生产速率为3.64mol/m2/a,与Treguer等人的报道中南大洋平均的年生产力235mol/m2/a较为相近。真光层生产的生物硅向更深层水体输送的过程中,有64%发生溶解再循环回到水体中,因此表层生产出的生物硅以1.31mol/m2/a的输出通量继续向深海输送,同样与整个南大洋的平均输出通量148mol/m2/a相比较为接近。 (2)在普里兹湾到达沉积物海水界面的生物硅通量为1.09mol/m2/a,经过沉积物-海水界面的早期成岩转化过程后,埋葬的生物硅为0.86mol/m2/a,相对于在上层水体中生物硅的输出通量值,埋葬在沉积物中的生物硅占了66%,明显高于南大洋平均保存效率26%。
[Abstract]:The sea ice area of the Southern Ocean occupies an important position in the global change. In the global biogeochemical cycle, the elements of carbon and other sources play an important role in the global biogeochemical cycle. In the Southern Ocean, diatom is the main producer of the ecosystem, and is an important part of the biological pump. More than half of the organic carbon flux sent to the deep sea is diatom. Therefore, the study of the key biogeochemical processes in the Southern Ocean silicon cycle helps us to better understand the temporal and spatial changes in the carbon cycle of the Southern Ocean. The bay is the largest Bay in the India ocean sector of the Southern Ocean except the wader sea, Ross Sea, and the Southern Ocean, and is a typical marginal sea ice area. The research on the Del sea and the Ross Sea sea area is still very scarce and very lack of systematicness in the critical process of biosilicon in the bay of pre - Bay. On the basis of field data and experimental data, the key process of bio silicon cycling in the Southern Ocean is systematically studied, and the production, output and recycling efficiency of bio silicon are verified and quantified. The preservation mechanism of biogenic silicon in the bay is discussed. The main research content and main research results of this paper are as follows:
1. the production of biogenic silicon in the surface water of the Gulf of praise and its output process in the surface water.
(1) in the summer of 2013, the content of PBSi in the surface of the waters of the bay of Pro bays varies between 0.38-8.62 and mol/dm3. The distribution trend is 67 degree S, and the content of the South Bay is obviously higher than that of the Gulf of 67 [67]. The distribution is basically consistent with the distribution of the surface Chla. The vertical distribution of PBSi is also very similar to the distribution of Chla, showing an obvious higher than the content of the 50m layer. The trend of water content below 50m. Compared with the previous voyage data, the content of PBSi has a certain interannual variation, but the distribution in the bay is basically similar.
(2) the biological factor is the main controlling factor of the distribution of PBSi in the bay. According to the average content of PBSi and the average content of Chla in different years, the average content of the surface PBSi in the sea area outside Bay Bay is very consistent with the annual change of the average content of Chla. The climate change will produce a certain shadow on the sea ice changes in the bay. The corresponding changes in the number of population structure in the number population structure of the corresponding phytoplankton in the number of population also have a corresponding effect on the content and distribution of PBSi.
(3) the average ratio of Si/C in the surface water body of the bay Bay is 0.21 and the average ratio of the South Ocean in the report. With the increase of water depth, the Si/C ratio in the Bay and the water in the bay is reduced, indicating that there is a decoupling relationship between the biological silicon and organic carbon output process in the upper water body of the Bay, and the degradation of organic carbon in the upper water body of the bay. The transformation process is less than the dissolution process of biogenic silicon, which makes the output of PBSi in 50m water body below POC, which ultimately leads to the decrease of Si/C ratio.
(4) using the seasonal consumption of silicate to estimate the consumption rate of silicate in the surface water body on the surface water of the Bay, that is, the production rate of biosilicon, the result is 14.54mmol/m2/d, and the production rate of biosilicon estimated by the ratio of Si/C and the field measured primary productivity data is 20.20mmol/m2/d. and the other seas of the South Ocean. Compared with the higher biosilicon production level, the results obtained by using the field silicon stable isotope culture experimental data combined with the accumulation of biosilicon content in the water show that the bio silicon 89% produced in the surface water body of the bay Bay is exported from the surface, and the biosilicon is 36% in the 50m water body to the water body of the 200m water body. Only a few parts of the crystalline silicon are dissolved in the surface of the surface, and a large amount of dissolution has occurred during the subsequent transportation to the deeper 200m water body, which accounts for the 64%. of the surface layer.
2. the vertical transport process of biogenic silicon in the deep and middle waters of the river range.
(1) the particulates in the interglacial Lake area in the bay Bay are mainly diatom aggregates and are also mixed with some unpolymerized diatom monomers. In addition to the diatom aggregates, the outer settlement particles in the parezi Bay Bay can not be ignored at the peak of the peak flux in summer. There are some differences in types, reflecting the differences of particulate matter sources and related biogeochemical processes in the upper waters of different areas of the Gulf.
(2) according to the data of the particle composition of the three survey years we obtained, the source component is the main composition of the particulate matter. In the source component of the particle, the main contribution is the bio silicon flux. The flux of bio silicon organic carbon and other raw materials is mainly influenced by the growth of floating plant in the upper water body, showing a significant seasonal variation. The peak value of fluxes appeared in the summer of 1-2 months in the summer, and the minimum value appeared in the month of the winter of 5-7. In the same period of summer, the value of the bio silicon flux in the ice lake area in the Bay was obviously higher than that of the biological silicon flux in the deep sea sea.
(3) the effect of climate change on the growth of phytoplankton in the surface waters of the bay of pre - Bay is also responsive to the source material flux in the deep water body. In 2009/2010, in December, the phytoplankton in the bay of Pro bay had reached the maximum and continued to decline until January in the summer of December due to the El Nino effect. The effect of La Nina incident on the growth of phytoplankton in the interglacial Lake area of the catcher was significantly lower than that in the same period of 2009/2010 years, resulting in obvious annual differences in the summer and summer 2010/2011 fluxes in 2009/2010 and in the summer.
(4) the Si/C ratio of particles in deep water in 2009/2010 and 2010/2011 is 2.5 and 1.8 respectively in summer, which is obviously greater than the ratio of Si/C in the 200m water layer. It shows that the degree of organic carbon re mineralization is much greater than that of the biological silicon in the process of transporting the particles from the upper water body to the deep water body. The phytoplankton gradually aging from the surface of the surface to death, and most of the diatoms remained only empty shells. At this time, the organic carbon was degraded rapidly, which resulted in a significant increase in the Si:C ratio in the deep water body.
(5) the conservation efficiency of biosilicon in the waters of the bay is estimated by the ratio of the flux of 480m biological silicon to the production of the surface biogenic silicon in the deep waters of the bay Bay, 26% in summer and 24% in the summer of 2009/2010, and 25% in the two in the summer of 2010/2011, indicating that the biological silicon produced in the surface layer has 75% before settling to the sediment. Biogenic silicon dissolved in the water body produced in the surface water body of the bay Bay in the bay of 50-200m and dissolved (64% dissolve out) in a large scale (dissolve out) in the water body below 200m, although the dissolution continues in the process of water transport below the water body, but its degree is obviously less than the upper water body.
3. the biogenic silicon recycling process in the surface sediments of the Gulf of praise.
(1) the content of biogenic silicon in the surface sediments of pryd Bay varies between 4.89-75.32%, and in the zonal space distribution, the content of biological silicon shows an obvious 67 degree S distribution in the deep sea area outside the Gulf of 67 [67] in the interglacial region of the South Bay area. The distribution of the biological silicon in the columnar sediments at the different latitude of pryd Bay shows that at 67 degree S The distribution trend of bio silicon in the columnar sediments in the north of the bay is different from that in the bay. In the 66.50S sediments outside the Bay, the content of biological silicon increases with the depth, and the content fluctuates little. In the 67.5 S columnar sediments in the Bay, the content of the bio silicon content is obvious, and in general it decreases with the increase of depth. Trend.
(2) the spatial distribution of biological silicon and organic carbon in the surface sediments, the molar ratio of the molar ratio of Si/C elements to the ratio of Si/C elements to 4.60-18.48, is far greater than the Si/C ratio in the deep water and 200m water particles. The vertical distribution of organic carbon is different from that of the biological silicon, indicating that the two are in the process of deposition and burial. Differences in physical, chemical and biological reactions experienced.
(3) the change range of DSi content in the interstitial water of the Bay sediment is large, and the content of DSi in the surface interstitial water varies between 118.15-552.00 and mol/dm3, with an average of 352.43 mu mol/dm3, the highest value appears in the Bay inland shelf, and the lowest value appears at the intersection of the continental slope and the shelf at the boundary of the continental shelf. Most of the station sediments are in the interstitial water DSi A similar vertical distribution is presented, that is, there is an obvious concentration gradient near the sediment water interface DSi, from the average content of 75.19 mu mol/dm3 in the overlying water to 352.43 mu mol/dm3 in the surface interstitial water, but there is little difference between the silicate content and the surface gap water content in the Forlam shoal area. (4) the sediment in the Bay sediments. Under the seawater interface, the distribution of DSi content increased exponentially with depth, and then gradually reached a stable gradual concentration Cd, which was opposite to the vertical distribution of the biosilicon in the sediments, indicating that the rapid dissolution was the main process during the gradual burial process of the biogenic silicon in the Bay, which made the silicate in the interstitial water rapid. The high value of silicate Cd in the interstitial water of preconcentration Bay appears at the station of 67.5 S and 68 S in the Bay inland shelf, which is 644.0165126 mol/dm3 respectively, while the Cd of the station near the ice edge of the bay is obviously lower than the continental shelf. The lowest value appears at the 47284 u mol/dm3 of the bay mouth Rahm shoal 66.86 degree S station.
(5) the one dimensional model method is used to estimate the release fluxes of silicate in the sediments of the Bay sediments. The results show that the release flux of silicic acid in the sediments is reduced from the slope of the bay to the Bay in the bay Bay, and the maximum flux of 115mmol/m2/d appears at the Bay mouth area near the flats. The release rate of the 67.5 degree S station in the shelf area of the Bay shelf is now minimum of 0.45mmol/m2/d for the site of the shelf area obtained by the 0.30mmol/m2/d. field test method, while the release rates obtained in the periglacial and bay mouth areas are 063mmol/m2/d and 0.60mmol/m2/d., respectively, and the corresponding site flux estimated by the model method. The range of value change is similar. The diffusion flux of DSi is mainly derived from the dissolution and preservation mechanism of biological silicon in the surface sediments of.4. Bay, which is within 5cm of the upper layer of the sediment.
(1) the results of the study of the dissolution properties of sediment biosilicon by batch experiment showed that the solubility of bio silicon in the surface sediments of the continental shelf and the periginum area under the laboratory conditions was 1936 mu mol/dm3., respectively, and the concentration of the dissolved organic silicon in the sediments of the margin of the periginum was lower than that of the sediments above 5cm. In addition to the obvious decrease in the shelf position of the shelf, the solubility of the biogenic silicon between 5-20cm is relatively small with the upper level. Compared with the vertical distribution of DSi in the interstitial water of the sediment Bay, the average value of the gap water Cd is obviously lower than the solubility of the DSi in the laboratory.
(2) according to the Batch experimental data, the laboratory dissolution rate of biogenic silicon in the surface sediments of the perige Bay and periginum area is 201 mu, respectively, and 1.09 mu mol/h/g. is in the range of 0-5cm in different regions. The dissolution rate of biosilicon is obviously decreased with the depth of the sediments, and the basic changes in the sediments below 5cm are not significant. In the laboratory simulation experiments, the dissolution rate of the surface sediments in the sediments of the Bay sediments is higher than that in the deep sediments, indicating that the dissolution of the biological silicon in the surface of the surface of the sediments (0-4.5cm) is much faster than that in the deep sediments.
(3) the burial flux of biogenic silicon in the sediments of the bay is between 0.09-2.06mol/m2/a, the highest burial amount appears in the 67.5-680S area of the Bay inland shelf, the lowest value appears in the bay area Rahm shoal area.
【学位授予单位】：中国地质大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：P736.4
本文编号：2124764
[Abstract]:The sea ice area of the Southern Ocean occupies an important position in the global change. In the global biogeochemical cycle, the elements of carbon and other sources play an important role in the global biogeochemical cycle. In the Southern Ocean, diatom is the main producer of the ecosystem, and is an important part of the biological pump. More than half of the organic carbon flux sent to the deep sea is diatom. Therefore, the study of the key biogeochemical processes in the Southern Ocean silicon cycle helps us to better understand the temporal and spatial changes in the carbon cycle of the Southern Ocean. The bay is the largest Bay in the India ocean sector of the Southern Ocean except the wader sea, Ross Sea, and the Southern Ocean, and is a typical marginal sea ice area. The research on the Del sea and the Ross Sea sea area is still very scarce and very lack of systematicness in the critical process of biosilicon in the bay of pre - Bay. On the basis of field data and experimental data, the key process of bio silicon cycling in the Southern Ocean is systematically studied, and the production, output and recycling efficiency of bio silicon are verified and quantified. The preservation mechanism of biogenic silicon in the bay is discussed. The main research content and main research results of this paper are as follows:
1. the production of biogenic silicon in the surface water of the Gulf of praise and its output process in the surface water.
(1) in the summer of 2013, the content of PBSi in the surface of the waters of the bay of Pro bays varies between 0.38-8.62 and mol/dm3. The distribution trend is 67 degree S, and the content of the South Bay is obviously higher than that of the Gulf of 67 [67]. The distribution is basically consistent with the distribution of the surface Chla. The vertical distribution of PBSi is also very similar to the distribution of Chla, showing an obvious higher than the content of the 50m layer. The trend of water content below 50m. Compared with the previous voyage data, the content of PBSi has a certain interannual variation, but the distribution in the bay is basically similar.
(2) the biological factor is the main controlling factor of the distribution of PBSi in the bay. According to the average content of PBSi and the average content of Chla in different years, the average content of the surface PBSi in the sea area outside Bay Bay is very consistent with the annual change of the average content of Chla. The climate change will produce a certain shadow on the sea ice changes in the bay. The corresponding changes in the number of population structure in the number population structure of the corresponding phytoplankton in the number of population also have a corresponding effect on the content and distribution of PBSi.
(3) the average ratio of Si/C in the surface water body of the bay Bay is 0.21 and the average ratio of the South Ocean in the report. With the increase of water depth, the Si/C ratio in the Bay and the water in the bay is reduced, indicating that there is a decoupling relationship between the biological silicon and organic carbon output process in the upper water body of the Bay, and the degradation of organic carbon in the upper water body of the bay. The transformation process is less than the dissolution process of biogenic silicon, which makes the output of PBSi in 50m water body below POC, which ultimately leads to the decrease of Si/C ratio.
(4) using the seasonal consumption of silicate to estimate the consumption rate of silicate in the surface water body on the surface water of the Bay, that is, the production rate of biosilicon, the result is 14.54mmol/m2/d, and the production rate of biosilicon estimated by the ratio of Si/C and the field measured primary productivity data is 20.20mmol/m2/d. and the other seas of the South Ocean. Compared with the higher biosilicon production level, the results obtained by using the field silicon stable isotope culture experimental data combined with the accumulation of biosilicon content in the water show that the bio silicon 89% produced in the surface water body of the bay Bay is exported from the surface, and the biosilicon is 36% in the 50m water body to the water body of the 200m water body. Only a few parts of the crystalline silicon are dissolved in the surface of the surface, and a large amount of dissolution has occurred during the subsequent transportation to the deeper 200m water body, which accounts for the 64%. of the surface layer.
2. the vertical transport process of biogenic silicon in the deep and middle waters of the river range.
(1) the particulates in the interglacial Lake area in the bay Bay are mainly diatom aggregates and are also mixed with some unpolymerized diatom monomers. In addition to the diatom aggregates, the outer settlement particles in the parezi Bay Bay can not be ignored at the peak of the peak flux in summer. There are some differences in types, reflecting the differences of particulate matter sources and related biogeochemical processes in the upper waters of different areas of the Gulf.
(2) according to the data of the particle composition of the three survey years we obtained, the source component is the main composition of the particulate matter. In the source component of the particle, the main contribution is the bio silicon flux. The flux of bio silicon organic carbon and other raw materials is mainly influenced by the growth of floating plant in the upper water body, showing a significant seasonal variation. The peak value of fluxes appeared in the summer of 1-2 months in the summer, and the minimum value appeared in the month of the winter of 5-7. In the same period of summer, the value of the bio silicon flux in the ice lake area in the Bay was obviously higher than that of the biological silicon flux in the deep sea sea.
(3) the effect of climate change on the growth of phytoplankton in the surface waters of the bay of pre - Bay is also responsive to the source material flux in the deep water body. In 2009/2010, in December, the phytoplankton in the bay of Pro bay had reached the maximum and continued to decline until January in the summer of December due to the El Nino effect. The effect of La Nina incident on the growth of phytoplankton in the interglacial Lake area of the catcher was significantly lower than that in the same period of 2009/2010 years, resulting in obvious annual differences in the summer and summer 2010/2011 fluxes in 2009/2010 and in the summer.
(4) the Si/C ratio of particles in deep water in 2009/2010 and 2010/2011 is 2.5 and 1.8 respectively in summer, which is obviously greater than the ratio of Si/C in the 200m water layer. It shows that the degree of organic carbon re mineralization is much greater than that of the biological silicon in the process of transporting the particles from the upper water body to the deep water body. The phytoplankton gradually aging from the surface of the surface to death, and most of the diatoms remained only empty shells. At this time, the organic carbon was degraded rapidly, which resulted in a significant increase in the Si:C ratio in the deep water body.
(5) the conservation efficiency of biosilicon in the waters of the bay is estimated by the ratio of the flux of 480m biological silicon to the production of the surface biogenic silicon in the deep waters of the bay Bay, 26% in summer and 24% in the summer of 2009/2010, and 25% in the two in the summer of 2010/2011, indicating that the biological silicon produced in the surface layer has 75% before settling to the sediment. Biogenic silicon dissolved in the water body produced in the surface water body of the bay Bay in the bay of 50-200m and dissolved (64% dissolve out) in a large scale (dissolve out) in the water body below 200m, although the dissolution continues in the process of water transport below the water body, but its degree is obviously less than the upper water body.
3. the biogenic silicon recycling process in the surface sediments of the Gulf of praise.
(1) the content of biogenic silicon in the surface sediments of pryd Bay varies between 4.89-75.32%, and in the zonal space distribution, the content of biological silicon shows an obvious 67 degree S distribution in the deep sea area outside the Gulf of 67 [67] in the interglacial region of the South Bay area. The distribution of the biological silicon in the columnar sediments at the different latitude of pryd Bay shows that at 67 degree S The distribution trend of bio silicon in the columnar sediments in the north of the bay is different from that in the bay. In the 66.50S sediments outside the Bay, the content of biological silicon increases with the depth, and the content fluctuates little. In the 67.5 S columnar sediments in the Bay, the content of the bio silicon content is obvious, and in general it decreases with the increase of depth. Trend.
(2) the spatial distribution of biological silicon and organic carbon in the surface sediments, the molar ratio of the molar ratio of Si/C elements to the ratio of Si/C elements to 4.60-18.48, is far greater than the Si/C ratio in the deep water and 200m water particles. The vertical distribution of organic carbon is different from that of the biological silicon, indicating that the two are in the process of deposition and burial. Differences in physical, chemical and biological reactions experienced.
(3) the change range of DSi content in the interstitial water of the Bay sediment is large, and the content of DSi in the surface interstitial water varies between 118.15-552.00 and mol/dm3, with an average of 352.43 mu mol/dm3, the highest value appears in the Bay inland shelf, and the lowest value appears at the intersection of the continental slope and the shelf at the boundary of the continental shelf. Most of the station sediments are in the interstitial water DSi A similar vertical distribution is presented, that is, there is an obvious concentration gradient near the sediment water interface DSi, from the average content of 75.19 mu mol/dm3 in the overlying water to 352.43 mu mol/dm3 in the surface interstitial water, but there is little difference between the silicate content and the surface gap water content in the Forlam shoal area. (4) the sediment in the Bay sediments. Under the seawater interface, the distribution of DSi content increased exponentially with depth, and then gradually reached a stable gradual concentration Cd, which was opposite to the vertical distribution of the biosilicon in the sediments, indicating that the rapid dissolution was the main process during the gradual burial process of the biogenic silicon in the Bay, which made the silicate in the interstitial water rapid. The high value of silicate Cd in the interstitial water of preconcentration Bay appears at the station of 67.5 S and 68 S in the Bay inland shelf, which is 644.0165126 mol/dm3 respectively, while the Cd of the station near the ice edge of the bay is obviously lower than the continental shelf. The lowest value appears at the 47284 u mol/dm3 of the bay mouth Rahm shoal 66.86 degree S station.
(5) the one dimensional model method is used to estimate the release fluxes of silicate in the sediments of the Bay sediments. The results show that the release flux of silicic acid in the sediments is reduced from the slope of the bay to the Bay in the bay Bay, and the maximum flux of 115mmol/m2/d appears at the Bay mouth area near the flats. The release rate of the 67.5 degree S station in the shelf area of the Bay shelf is now minimum of 0.45mmol/m2/d for the site of the shelf area obtained by the 0.30mmol/m2/d. field test method, while the release rates obtained in the periglacial and bay mouth areas are 063mmol/m2/d and 0.60mmol/m2/d., respectively, and the corresponding site flux estimated by the model method. The range of value change is similar. The diffusion flux of DSi is mainly derived from the dissolution and preservation mechanism of biological silicon in the surface sediments of.4. Bay, which is within 5cm of the upper layer of the sediment.
(1) the results of the study of the dissolution properties of sediment biosilicon by batch experiment showed that the solubility of bio silicon in the surface sediments of the continental shelf and the periginum area under the laboratory conditions was 1936 mu mol/dm3., respectively, and the concentration of the dissolved organic silicon in the sediments of the margin of the periginum was lower than that of the sediments above 5cm. In addition to the obvious decrease in the shelf position of the shelf, the solubility of the biogenic silicon between 5-20cm is relatively small with the upper level. Compared with the vertical distribution of DSi in the interstitial water of the sediment Bay, the average value of the gap water Cd is obviously lower than the solubility of the DSi in the laboratory.
(2) according to the Batch experimental data, the laboratory dissolution rate of biogenic silicon in the surface sediments of the perige Bay and periginum area is 201 mu, respectively, and 1.09 mu mol/h/g. is in the range of 0-5cm in different regions. The dissolution rate of biosilicon is obviously decreased with the depth of the sediments, and the basic changes in the sediments below 5cm are not significant. In the laboratory simulation experiments, the dissolution rate of the surface sediments in the sediments of the Bay sediments is higher than that in the deep sediments, indicating that the dissolution of the biological silicon in the surface of the surface of the sediments (0-4.5cm) is much faster than that in the deep sediments.
(3) the burial flux of biogenic silicon in the sediments of the bay is between 0.09-2.06mol/m2/a, the highest burial amount appears in the 67.5-680S area of the Bay inland shelf, the lowest value appears in the bay area Rahm shoal area.
【学位授予单位】：中国地质大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：P736.4
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