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1.
We present an independent calibration model for the determination of biogenic silica (BSi) in sediments, developed from analysis of synthetic sediment mixtures and application of Fourier transform infrared spectroscopy (FTIRS) and partial least squares regression (PLSR) modeling. In contrast to current FTIRS applications for quantifying BSi, this new calibration is independent from conventional wet-chemical techniques and their associated measurement uncertainties. This approach also removes the need for developing internal calibrations between the two methods for individual sediments records. For the independent calibration, we produced six series of different synthetic sediment mixtures using two purified diatom extracts, with one extract mixed with quartz sand, calcite, 60/40 quartz/calcite and two different natural sediments, and a second extract mixed with one of the natural sediments. A total of 306 samples—51 samples per series—yielded BSi contents ranging from 0 to 100 %. The resulting PLSR calibration model between the FTIR spectral information and the defined BSi concentration of the synthetic sediment mixtures exhibits a strong cross-validated correlation ( \( {\text{R}}^{ 2}_{\text{cv}} \)  = 0.97) and a low root-mean square error of cross-validation (RMSECV = 4.7 %). Application of the independent calibration to natural lacustrine and marine sediments yields robust BSi reconstructions. At present, the synthetic mixtures do not include the variation in organic matter that occurs in natural samples, which may explain the somewhat lower prediction accuracy of the calibration model for organic-rich samples.  相似文献   

2.
The quality and interpretability of the paleobiological record depends on the preservation of morphological and geochemical fossils. Siliceous microfossils and sedimentary pigments are often cornerstones in paleoecology, although the microbial and geochemical processes conducive to their preservation remain poorly constrained. We examined sediments from an alpine lake in Banff National Park (Alberta, Canada) where diatom frustules are completely dissolved within 50 years of deposition. Diatom dissolution, silica recycling, and diagenetic alteration of algal pigments were investigated, in conjunction with porewater geochemistry and microelectrode profiling of the sediment–water interface. Analysis of sediment trap material showed ~90% of biogenic silica (BSi) production is lost prior to burial. Silica flux calculations, based on dissolved silica (as H4SiO4) in pore-waters, show a further ~6% of total BSi is returned to the water column from the upper 4 cm of sediments, implying that only ~4% of total BSi is permanently archived in sediments. In situ sediment pH and O2 profiles reveal that aerobic respiration by bacteria fully consumes oxygen by a depth of 4 mm into the sediment, with associated strong pH and redox gradients. During sedimentation and early diagenesis, diatoms undergo loss of extracellular polymeric substances that coat their frustules, promoting silica dissolution and leading to the loss of the microfossil record by a depth of 3.25 cm. Sedimentary pigments similarly undergo rapid degradation, but diatom-related carotenoids persist below the depth of silica dissolution. This work provides new insights on diagenetic processes in lakes, with broad implications for the interpretation of sedimentary proxies for algal production.  相似文献   

3.
We explored the use of hydrogen peroxide (H2O2) of different strengths (1, 3, 6, and 9%) in the preparation of lake-sediment samples for macroscopic charcoal determination. In previous work we found that soaking sediment samples in 3% H2O2 for 24 h disaggregates samples and removes or bleaches some non-charred organic material, making it easier to distinguish macroscopic charcoal particles from dark, non-charred organic matter. To determine whether this procedure alters charcoal particle abundances and size distributions, we tested the procedure on wood and grass samples containing a known number of laboratory-produced charcoal particles from different size classes (250–500, 500–1,000, and 1,000–2,000 μm). For both sample types, we found that post-treatment numbers were not statistically different from pre-treatment numbers. However, application of hydrogen peroxide solutions of 3, 6, and 9% to fossil charcoal assemblages in a sediment core from northwestern Costa Rica reduced charcoal concentrations markedly, by bleaching or removing particles that were not fully charred. We also tested the replicability of charcoal counts by conducting enumerations on multiple samples from the same stratigraphic depths in a core. Horizontally adjacent samples from the same core may vary in charcoal concentration. This finding has implications for establishing sample volume in macroscopic charcoal analysis.  相似文献   

4.
通过对九寨沟箭竹海沉积物样品中生物硅( BSi)含量的分析,讨论箭竹海沉积物中BSi含量与总有机碳(TOC)及粒度的关系,进而探讨BSi含量反映自然和人类因素对湖泊水体和沉积物的影响.箭竹海沉积物中BSi含量介于5.5～ 15.8 mg/g之间,BSi含量与TOC呈显著正相关关系.BSi含量还较显著地受到粒度影响,较细颗粒沉积物对BSi有较强的吸附作用.箭竹海沉积物中BSi含量变化与气温波动关系不密切,主要反映了森林砍伐和旅游开发等人类活动对湖泊水体和沉积物的影响.  相似文献   

5.
We demonstrate the use of Fourier transform infrared spectroscopy (FTIRS) to make quantitative measures of total organic carbon (TOC), total inorganic carbon (TIC) and biogenic silica (BSi) concentrations in sediment. FTIRS is a fast and cost-effective technique and only small sediment samples are needed (0.01 g). Statistically significant models were developed using sediment samples from northern Sweden and were applied to sediment records from Sweden, northeast Siberia and Macedonia. The correlation between FTIRS-inferred values and amounts of biogeochemical constituents assessed conventionally varied between r = 0.84–0.99 for TOC, r = 0.85–0.99 for TIC, and r = 0.68–0.94 for BSi. Because FTIR spectra contain information on a large number of both inorganic and organic components, there is great potential for FTIRS to become an important tool in paleolimnology.  相似文献   

6.
Diatom-salinity records from sediment cores have been used to construct climate records of saline-lake basins. In many cases, this has been done without thorough understanding of the preservation potential of the diatoms in the sediments through time. The purpose of this study was to determine the biogeochemistry of silica in Devils Lake and evaluate the potential effects of silica cycling on diatom preservation. During the period of record, 1867–1999, lake levels have fluctuated from 427 m above sea level in 1940 to 441.1 m above sea level in 1999. The biogeochemistry of silica in Devils Lake is dominated by internal cycling. During the early 1990s when lake levels were relatively high, about 94% of the biogenic silica (BSi) produced in Devils Lake was recycled in the water column before burial. About 42% of the BSi that was incorporated in bottom sediments was dissolved and diffused back into the lake, and the remaining 58% was buried. Therefore, the BSi accumulation rate was about 3% of the BSi assimilation rate. Generally, the results obtained from this study are similar to those obtained from studies of the biogeochemistry of silica in large oligotrophic lakes and the open ocean where most of the BSi produced is recycled in surface water. During the mid 1960s when lake levels were relatively low, BSi assimilation and water-column dissolution rates were much higher than when lake levels were high. The BSi assimilation rate was as much as three times higher during low lake levels. Even with the much higher BSi assimilation rate, the BSi accumulation rate was about three times lower because the BSi water-column dissolution rate was more than 99% of the BSi assimilation rate compared to 94% during high lake levels. Variations in the biogeochemistry of silica with lake level have important implications for paleolimnologic studies. Increased BSi water-column dissolution during decreasing lake levels may alter the diatom-salinity record by selectively removing the less resistant diatoms. Also, BSi accumulation may be proportional to the amount of silica input from tributary sources. Therefore, BSi accumulation chronologies from sediment cores may be effective records of tributary inflow.  相似文献   

7.
Sediment cores from Lone Spruce Pond (60.007°N, 159.143°W), southwestern Alaska, record paleoenvironmental changes during the global Last Glacial Maximum (LGM), and during the last 14,500 calendar years BP (14.5?cal?ka). We analyzed the abundance of organic matter, biogenic silica, carbon, and nitrogen, and the isotope ratios of C and N, magnetic susceptibility, and grain-size distribution of bulk sediment, abundance of alder shrub (Alnus) pollen, and midge (Chironomidae and Chaoboridae) assemblages in a 4.7-m-long sediment sequence from the depocenter at 22?m water depth. The basal unit contains macrofossils dating to 25?C21?cal?ka (the global LGM), and is interpreted as glacial-lacustrine sediment. The open water requires that the outlet of the Ahklun Mountain ice cap had retreated to within 6?km of the range crest. In addition to cladocerans and diatoms, the glacial-lacustrine mud contains chironomids consistent with deep, oligotrophic conditions; several taxa associated with relatively warm conditions are present, suggestive of relative warmth during the global LGM. The glacial-lacustrine unit is separated from the overlying non-glacial lake sediment by a possible disconformity, which might record a readvance of glacier ice. Non-glacial sediment began accumulating around 14.5?cal?ka, with high flux of mineral matter and fluctuating physical and biological properties through the global deglacial period, including a reversal in biogenic-silica (BSi) content during the Younger Dryas (YD). During the global deglacial interval, the ??13C values of lake sediment were higher relative to other periods, consistent with low C:N ratios (8), and suggesting a dominant atmospheric CO2 source of C for phytoplankton. Concentrations of aquatic faunal remains (chironomids and Cladocera) were low throughout the deglacial interval, diversity was low and warm-indicator taxa were absent. Higher production and air temperatures are inferred following the YD, when bulk organic-matter (OM) content (LOI 550?°C) increased substantially and permanently, from 10 to 30?%, a trend paralleled by an increase in C and N abundance, an increase in C:N ratio (to about 12), and a decrease in ??13C of sediment. Post-YD warming is marked by a rapid shift in the midge assemblage. Between 8.9 and 8.5?cal?ka, Alnus pollen tripled (25?C75?%), followed by the near-tripling of BSi (7?C19?%) by 8.2?cal?ka, and ??15N began a steady rise, reflecting the buildup of N and an increase in denitrification in soils. Several chironomid taxa indicative of relatively warm conditions were present throughout the Holocene. Quantitative chironomid-based temperature inferences are complicated by the expansion of Alnus and resulting changes in lake nutrient status and production; these changes were associated with an abrupt increase in cladoceran abundance and persistent shift in the chironomid assemblage. During the last 2,000?years, chironomid-assemblage changes suggest cooler temperatures, and BSi and OM values were generally lower than their maximum Holocene values, with minima during the seventh and eighth centuries, and again during the eighteenth century.  相似文献   

8.
Organic-rich sediment from Lake Louise, a dystrophic sinkhole lake in south Georgia, displays variations in C, N, P, C/N, δ13C, δ15N, biogenic silica (BSi) and diatom flora that document changes in trophic state over the past ~9,500 years. The lake initially was oligotrophic and moderately productive, but by the middle Holocene a rising regional water table, driven by eustatic sea level rise, caused expansion of wetlands around the lake and a shift to humic waters. Low rates of sediment accumulation, low C contents, rising C/N, and light δ13C and δ15N indicate this was a time of low productivity, more anoxic bottom waters and extensive recycling of littoral organic matter. These conditions persisted until ~1800 AD when a physical disturbance to the watershed, probably the Great Hurricane of 1780, resulted in a dramatic increase in productivity that has continued to the present day. We attribute this shift, recorded by a >tenfold increase in sediment accumulation rate, higher C, P, and δ15N, and lower BSi, to establishment of an inflow stream that increased nutrient delivery to the lake, raised water level, and expanded the wetland area around the lake. Since ~1930, logging, farming, and highway construction have impacted the lake, further accelerating biological productivity as well as the delivery of terrigenous sediment. Results of this study illustrate the potential of a single, catastrophic event to permanently alter the hydrology and chemistry of a lacustrine system and confirm that dystrophic lakes can be highly productive and therefore promising targets for paleolimnological study.  相似文献   

9.
The change in dissolved inorganic δ13C in the ocean resulting from the change in δ13C in atmospheric CO2 owing to anthropogenic activities (the Suess effect) is well known. The need to correct for the Suess effect when applying δ13C in organic matter in lacustrine sediment deposited during the anthropocene as a productivity proxy, is widely although not universally acknowledged. This paper reviews conceptions about the Suess effect in lacustrine δ13Corg and methods to adjust for the Suess effect when δ13Corg is used to infer recent changes in aquatic productivity. Lake Tanganyika is used as an example to illustrate the necessity of the correction. When the Suess effect is not considered, interpretations of sediment core data can result that are opposite to those achieved with the correction applied, as is here shown in Lake Tanganyika and in other lakes. A new method to correct for the Suess effect is provided which has the advantage of being applicable to data for a larger period (1700–2000) than methods currently available. In addition, Lake Tanganyika is shown to be a net sink for CO2.  相似文献   

10.
Major components of lacustrine sediments, such as carbonates, organic matter, and biogenic silica, provide significant paleoenvironmental information about lake systems. Fourier transform infrared spectroscopy (FTIR) and scanning X-ray fluorescence (XRF) techniques are fast, cost effective, efficient methods to determine the relative abundances of these components. We investigate the potential of these techniques using sediments from two large lakes, Lake Malawi in Africa and Lake Qinghai in China. Our results show statistically significant correlations of conventionally measured concentrations of carbonate (%CaCO3), total organic carbon (%TOC), and biogenic silica (%BSi), with absorbance in the corresponding FTIR spectral regions and with XRF elemental ratios including calcium:titanium (Ca/Ti), incoherent:coherent X-ray scatter intensities (Inc/Coh), and silicon:titanium (Si/Ti), respectively. The correlation coefficients (R) range from 0.66 to 0.96 for comparisons of FTIR results and conventional measurements, and from 0.70 to 0.90 for XRF results and conventional measurements. Both FTIR and XRF techniques exhibit great potential for rapid assessment of inorganic and organic contents of lacustrine sediments. However, the relationship between XRF-ratios or FTIR-absorbances and abundances of corresponding sedimentary components can vary with sediment source and lithology.  相似文献   

11.
The geochemistry of lake (Renstradträsket) and estuarine (Pieni Pernajanlahti Bay) sediment was investigated in a medium sized watershed draining to the Gulf of Finland, Baltic Sea. Catchment land-use types were compared and found similar. Sediment cores were dated using 210Pb- and 137Cs-chronologies and analyzed for Al, K, Cu, Zn, Fe, Mn, phosphorus fractions, TN, TC and biogenic silica (BSi). Differences between the sediment cores were studied by using linear regression analysis and principal components analysis (PCA). Despite similarities in catchment land-use and history, the sediment geochemical profiles of the sites varied significantly. Some of the differences could be related to differences in chemical sedimentation environment (lacustrine versus estuarine). TP concentration was found to be positively correlated with sediment iron content in estuarine sediment but negatively correlated with Fe in lake sediment. In the estuarine core sedimentary iron was not correlated to lithogenic potassium and aluminum but in the lake core the iron seemed to be lithogenic in origin, as suggested by the strong positive correlations (r 2 = 0.95–0.96) between these three variables. Most similarities among the cores were found in Al concentrations. Estuarine nutrient profiles appeared relatively monotonous compared to the lake core. This is probably due to more vigorous mixing of the sediments that may ensure more rapid and complete consumption of the organic matter deposited on the bottom of the estuary. Therefore the lake sediment appeared to preserve the historical record of eutrophication better. Biologically less active and more particle-bound materials like the trace metals Cu and Zn seemed to retain good records of anthropogenic impact also in the estuarine core. The study highlights the need to take the sedimentation environment into account when interpreting geochemical record.  相似文献   

12.
Biogenic Silica (BSi) has been one of the most important proxies for determining the palaeoclimate from Lake Baikal over glacial-interglacial cycles. Concentrations (calculated through a 1% Na2CO3 wet-alkaline digestion) at a site in the north basin, however, reveal consistently low values during MIS 3 compared to greater than tenfold changes in diatom concentrations and biovolumes from c. 53.3–51.5 kyr BP. With similar glacial trends present at other low sedimentation sites, we suggest that significant amounts of BSi are removed from diatoms during glacials due to a relative increase in diatom dissolution at the sediment–water interface. This contrasts with existing results from other, higher sedimentation, sites such as those within the Selenga Delta, which display a strong relationship between diatoms and BSi. Site selection is therefore essential when searching for Heinrich and other glacial millennial-scale events in Lake Baikal, and we recommend that both BSi and diatom concentrations be calculated together in future studies.  相似文献   

13.
硅循环与碳循环密切相关,生物硅作为硅的重要载体,在全球硅循环中占有十分重要的地位。目前,人们对陆地生态系统的硅循环做了大量研究,但对极地地区硅的研究却极为少见。利用中国第五次北极考察获得的土壤与植物样品,对北极新奥尔松地区中国黄河站站基表层土壤中生物硅的含量及土壤和植被中生物硅(主要为植硅体)的形态进行了初步研究。主要结论为:北极新奥尔松地区中国黄河站站基附近表层土壤中颗粒有机碳的含量为1.00—69.3 mg·g-1,平均值为13.7 mg·g-1;颗粒有机氮含量为0.11—9.84 mg·g-1,平均值为1.43 mg·g-1;可溶态硅含量为3.90—26.3μg·g-1,平均值为10.7μg·g-1;生物硅含量为5.60—9.97 mg·g-1,平均值为7.56 mg·g-1,且其含量与土壤颗粒态有机碳和颗粒有机氮呈正相关关系,表明三者具有相似来源。北极表层土壤生物硅比温带、热带地区生物硅含量要高。植物样品中植硅体形态以帽形、圆形、平滑棒形、齿形、刺棒形和哑铃形等形态为主,大小在10—100μm之间。土壤样品中的植硅体主要来源于植物,形态分别为平滑棒形、刺棒形、圆形、哑铃形、鞍形、尖形和帽形,另外硅藻也是北极土壤中生物硅的组成部分,其中裸露土壤中藻类(羽纹纲硅藻)占生物硅的多数(93.3%)。对比发现,有植被覆盖的土壤中,土壤有机碳、可溶出态硅、生物硅含量和植硅体形态丰富度往往比无植被覆盖或寡植被区土壤高,这表明尽管该地区植被稀少,但植物生长对该地区土壤硅循环存在显著影响,值得进一步关注。  相似文献   

14.
Existing techniques for measuring sediment Biogenic Silica (BSi) concentrations rely largely on conventional (Si-only) wet-alkaline digestion methods. Although results have provided detailed palaeoenvironmental information, potential errors can arise in accounting for sources of non-BSi. Here, I compare a conventional Si-only method to a Si/Al wet-alkaline digestion method, which in theory provides a more robust correction for concentrations of non-BSi. Late glacial/Holocene-aged sediment from Lake Baikal, Russia was used for the comparison. Results showed no significant difference between the two techniques, indicating that existing Si-only BSi methods are suitable for reconstructing environmental changes when levels of digested non-BSi are low to moderate.  相似文献   

15.
Few studies have assessed the relative importance of landscape, land use history, climate, and regional heterogeneity on lake ecosystem processes, despite the likelihood that interactions among these factors must be important for controlling lake dynamics. We used 14 sediment measures from 20 lake cores in a climatically sensitive region of the prairie-forest border in southern Minnesota to (1) assess relationships between modern lake productivity (Carlson’s Trophic State Index [TSI]), modern land-use, catchment, and lake morphometry, and (2) contrast regional responses to climatic transitions from the ‘Medieval Climatic Anomaly’(1000–1350) to the ‘Little Ice Age’ (1350–1800) to ‘Modern’(~1980–1996 AD). TSI was significantly positively correlated with modern sedimentation rate, and accumulation rates of organic matter (OM), biogenic silica (BSi), and total phosphorus (TP). TSI was not significantly correlated with “modern” land cover, catchment, or lake morphometry characteristics, but total organic N(N) was negatively correlated with percent cultivation in the catchment area and negatively correlated with δ15N of bulk organic matter in sediment. Regional, among-lake heterogeneity was high over the past 1,000 years, but Little Ice Age (LIA) cooling appeared to result in an approximately 20% decline in OM, BSi and TP accumulation, while warming and cultural eutrophication of the past 150 years corresponded to a 200–400% increase in accumulation rates as well as an 80% increase in carbonates and a small but significant 10% drop in C/N ratios consistent with greater in-lake productivity. Our results indicate that climate does have regional effects on lake ecosystems but that among-lake variability is high, reflecting the importance of local factors and suggesting a need for (1) more explicit definition of what ‘regional’ means, (2) a focus on degree as well as direction of change, and (3) estimating accumulation rates based on multiple lakes and multiple cores within lakes.  相似文献   

16.
A 7.6-m lake sediment core from a marl lake, Lough Inchiquin, records variation in landscape evolution from 16,800 cal yrs B.P. to 5,540 cal yrs B.P. We observe significant variations (up to 12‰) in δ 13Corg and δ 13Ccalcite values that are interpreted to reflect secular changes in lake water δ 13CDIC values that result from a regional landscape transition from barren limestone bedrock to a forested ecosystem. Lake water δ 13CDIC values are therefore influenced by two isotopically distinct sources of carbon: terrestrial organic material (−27.1 to −31.2‰VPDB) via oxidized soil organic matter and weathered limestone bedrock (+3.4‰VPDB). Isotope excursions in lacustrine sediment records are forced not only by changes in productivity but also by changes in the terrestrial environment. This has profound implications for the interpretation of paleoclimate records derived from lacustrine sediment and suggests that selection of appropriate lakes can provide records of terrestrial change where other related records are not available.  相似文献   

17.
A continuous record of lacustrine sedimentation capturing the entire full-glacial period was obtained from Arolik Lake in the Ahklun Mountains, southwestern Alaska. Fluctuations in magnetic susceptibility (MS), grain size, organic-matter (OM) content, C/N ratios, 13C, and biogenic silica (BSi) record marked environmental changes within the lake and its watershed during the last 33 cal ka. Age control is provided by 31 14C ages on plant macrofossils in four cores between 5.2 and 8.6 m long. Major stratigraphic units are traceable throughout the lake subbottom in acoustical profiles, and provisional ages are derived for six prominent tephra beds, which are correlated among the cores. During the interstadial interval between 33 and 30 cal ka, OM and BSi contents are relatively high with values similar to those of the Pleistocene–Holocene transition, suggesting a similar level of aquatic productivity. During the glacial interval that followed (30–15 cal ka), OM and BSi decrease in parallel with declining summer insolation. OM and BSi values remain relatively uniform compared with the higher variability before and after this interval, and they show no major shifts that might correlate with climate fluctuations evidenced by the local moraine record, nor with other global climate changes. The glacial interval includes a clay-rich unit with a depauperate diatom assemblage that records the meltwater spillover of an ice-dammed lake. The meltwater pulse, and therefore the maximum extent of ice attained by a major outlet glacier of the Ahklun Mountain ice cap, lasted from 24 to 22 cal ka. The Pleistocene–Holocene transition (15–11 cal ka) exhibits the most prominent shifts in OM and BSi, but rapid and dramatic fluctuations in OM and BSi continue throughout the Holocene, indicating pronounced paleoenvrionmental changes.  相似文献   

18.
We analyzed 210Pb-dated sediment cores from four relatively shallow lakes (zmax < 10 m) in the Upper Ocklawaha River Basin, Florida, USA to compare primary producer community structure before and after anthropogenic impacts. We measured physical and chemical sediment variables including density, organic matter (OM), water-soluble phosphorus, polyphosphate (Poly-P), total P (TP), total carbon to total nitrogen mass ratios of OM (TC:TN), biogenic silica (diatoms, sponge spicules), total amorphous silica, and stable carbon and nitrogen isotope ratios of bulk OM. Principal component analysis showed that diatom biogenic silica, TC:TN, Poly-P and TP displayed discernible stratigraphic changes associated with the shift in the primary producer community. We applied k-means cluster analysis to these variables to identify macrophyte-derived, transitional, and phytoplankton-derived sediments. Our approach provides an objective method for identifying sediment sources that may be applied to shallow lakes in other regions. The four study lakes shifted from a macrophyte-dominated state to a transitional state before major anthropogenic disturbances, and became phytoplankton-dominated after ~1950.  相似文献   

19.
建立了以纳米二氧化钛（TiO2）作为吸附剂填充微柱,电感耦合等离子体质谱（ICP-MS）法测试Cu^2＋,Cd^2＋,Pb^2＋和Ni^2＋离子的分析方法．考察了不同pH值、洗脱液浓度、样品流速、体积和外源干扰离子的影响,实验结果表明在pH值8～10范围内待测离子可被TiO2定量吸附,2．0molL^-1HNO3可将吸附在微柱上的待测物完全洗脱,优化条件下本方法对溶液中Cu^2＋,Cd^2＋,Ph^2＋和M^2＋离子检出限分别为：0．02,0．01,0．01,0．02μgL～,相对标准偏差小于2％（n=7）,富集系数50倍．对水系沉积物标准物质（GBW07310）的测定值与标准值相一致,方法具有简便、快速,灵敏度高,重现性好的优点,可满足河口水体与沉积物样品中痕量金属元素定量分析的要求．  相似文献   

20.
本文利用中国南极科学考察航次获得的沉积物样品,采用分批（batch）实验方法,获取实验室生物硅溶解度,并结合间隙水中可溶性硅剖面,对普里兹湾沉积物中生物硅的溶出过程进行了初步研究。研究结果如下：在25℃,pH 8条件下,普里兹湾IV-10、 IS-4站表层沉积物中生物硅的实验室溶解度分别为1936、1539μmol/dm3,不同层次沉积物溶出结果显示随深度增加溶解度值降低。根据实验室溶解度数据与间隙水硅酸盐Cd的分析比较,表明研究站位沉积物生物硅的早期成岩过程中生物硅的溶出还伴随有其他化学过程。  相似文献   

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