鱼耳石微化学特征在湖库水质评价中的标型意义——以河北白洋淀和北京密云水库野生鲤鱼为例

对河北白洋淀和北京密云水库的野生鲤鱼耳石和水体中的微量元素进行了定量分析。白洋淀鱼耳石中诸微量元素含量均高于密云水库的鱼耳石,反映了白洋淀各水体较密云水库水体的环境复杂,污染程度高。统计分析结果表明,在鱼耳石中大致存在两类生物地球化学习性不同的元素,水体中第一类元素的变化不会引起耳石中相应元素的响应,如Au、K和Na;第二类元素的变化会引起耳石中相应元素的强烈响应,如As、Ba、Co、Cr、Fe、Sr和Zn。诸微量元素在耳石中富集的强弱顺序为,Zn>Sr>Se>Fe>As>Ba>K>Co>Au>Na>Cr。通过相关性分析发现,白洋淀和密云水库的鱼耳石和水体中对应微量元素平均含量的自然对数值之间均存在良好的线性关系。     

鲤鱼耳石Micro-CT特征与水域中重金属元素响应关系研究

将激光剥蚀等离子质谱技术(LA-ICP-MS)及显微X射线断层扫描技术(Micro-CT)运用到鲤鱼耳石对水环境中重金属元素的响应关系研究中. LA-ICP-MS结果表明白洋淀水域鲤鱼耳石中的Cu和Pb含量大于密云水库相应元素的含量;Micro-CT数据统计表明白洋淀水域鲤鱼耳石的Micro-CT值高于密云水库鲤鱼耳石的Micro-CT值.原子序数大的重金属元素Cu和Pb的富集程度是导致两研究区水域Micro-CT值差异的主要原因.耳石中的元素与水体元素具有相似的分布趋势,且对水体中的相应元素有明显富集作用.因此,鲤鱼耳石Micro-CT特征与水环境中重金属元素存在一定的耦合关系,可作为标型特征指示水体中重金属元素信息.     

X射线断层扫描技术在鲤鱼耳石对环境响应研究中的应用初探

作为生命矿物文石和球文石的载体,鱼耳石(fish otoliths)记载了鱼体生长过程中大量的环境信息。近30年来,其研究取得了很多成果,但利用医学技术的研究尚未见报道。文中尝试应用医学X射线断层扫描技术(CT)对取自河北白洋淀和北京密云水库的野生鲤鱼耳石进行分析研究。结果表明:白洋淀鲤鱼的星耳石和微耳石CT值均大于密云水库鲤鱼耳石相应的CT值,与白洋淀水体中的重金属元素含量明显高于密云水库水体中的重金属含量存在较好的相关性;同一水域星耳石与微耳石的CT值也存在明显差异,分析认为这种差异可能与元素的亲和性及占位方式有关。     

白洋淀和密云水库野生鲤鱼耳石热释光特征研究

鱼耳石的主体由生命矿物文石组成，其研究在过去二三十年中已取得了不少成果，但是将热释光技术用于鱼耳石的研究未见报道。本文对生长在河北白洋淀和北京密云水库的野生鲤鱼耳石的热释光曲线特征进行了研究，分析了两水域野生鲤鱼耳石中陷阱深度（E）值的差别。热释光测试结果显示，白洋淀10颗鲤鱼耳石样品热释光曲线的峰点温度（T）、发光强度（J）、积分强度（S）和半高宽（w）的均值大于密云水库，而且前者热释光曲线各参数值和E值的稳定程度均不如后者。分析还表明白洋淀鱼耳石在不同温度下的电子和空穴的逃逸几率（α）均大于密云水库。据调查，白洋淀各水体较密云水库水体的环境复杂，污染程度高。研究结果表明，鱼耳石的热释光曲线特征对鱼所生长的水体水质和水环境相当敏感，通过更深入研究，可能成为水质和水环境的重要标型。     

不同水域鲤鱼耳石CaCO3晶体结构特征与环境响应初探

鱼耳石主要成分是CaCO3,主要以文石(或霰石)形式存在,在过去四、五十年来在晶体结构研究方面取得了较多的成果.然而,不同水域鲤鱼耳石CaCO3晶体结构信息特征与环境响应研究却未见报道.本文对密云水库和白洋淀水域鲤鱼耳石X-粉晶衍射结果进行了研究,并分析了两地晶胞参数a0、b0、c0和单位晶胞体积的差异.结果显示,两地耳石样品均由霰石组成,分属三种不同结构:两种六方晶系P63/mmc(no.194)结构和一种斜方晶系Pbnm(Pnma no.62)结构.属于六方晶系的耳石样品中,密云水库鲤鱼耳石样品晶胞参     

陕西渭北聚煤区原煤的微量元素组成特征

对陕西省渭北主要煤田主采煤层中的As、Pb、Hg、Cd、Se、Cu、Sr、Ba、B等微量元素的分析结果表明：渭北原煤中Hg、Se、As、Pb、B含量明显高于地壳平均值，呈富集状态；Co、Cd与地壳平均值接近，Cu、Zn、Sr、Ba等元素均亏损。太原组和山西组由于成煤环境不同，煤质和原煤的微量元素组成特征存在一定的差异。太原组煤的友分和硫分均较山西组煤高，原煤中As、Hg、Se、Pb、Zn、B的合量明显高于山西组原煤，而山西组原煤中V、Cr、Cu、Mn、Ba的含量别明显高于大原组原煤。统计分析表明，As、Hg、Se、Pb、Cu等亲硫元素与铁呈显著的正相关关系，它们的赋存形式可能与煤中黄铁矿有关。     

吉南地区不同沉积环境原煤微量元素地球化学特征

对吉林南部地区煤矿主采煤层中的As、B、Ba、Cd、Cu、Hg、Pb、Se、Sr等微量元素的分析结果表明，太原组与山西组由于成煤环境不同，微量元素组成及含量存在一定的差异：太原组原煤中As、B、Hg、Pb、Se、Zn的含量明显高于山西组，山西组原煤中Ba、Cr、Cu、Mn、V的含量明显高于太原组。吉南煤区原煤中As、B、Hg、Pb、Se明显高于地壳元素平均值，呈富集状态，Co、Cd与地壳平均值接近，其他元素均亏损。与全国煤中微量元素相比，该区原煤中As、Ba、Co、Cr、Cu、Hg、Ni、Pb、Se、V、Zn的含量高于全国平均值，B、Mn、Sr含量低于全国平均值。微量元素赋存状态及相关分析表明，Fe与亲硫有害元素As、Cu、Hg、Pb、Se具有显著相关关系，说明煤中黄铁矿及其他硫化物是许多有害微量元素的重要载体。     

南沙海域西南海区表层沉积物地球化学特征

对南沙海域西南海区101个站位表层沉积物中的元素含量及分布特征分析表明：①元素含量的分布规律是Al、Fe、Mg、Ti、P、K、Na及Cu、Co、Ni、Pb、Zn、Ba、Zr含量从陆架到陆坡直到深海明显递增；Ca、Sr含量由陆架到陆坡递增，由陆坡向深海锐减；Si含量在陆坡低，在陆架和深海高。②沉积物中元素的分布和含量变化与沉积物类型有密切关系。粗粒沉积物中Si、Sr含量较高，细粒沉积物则相对富集Al、Fe、Mg、Ti、P、K、Na及Cu、Co、Ni、Pb、Zn、Ba、Zr等元素，并且随沉积物变细，其含量亦增加，在粘土中含量最高。③SiO2与其余常量组分均呈负相关，且随水深的增加，含量逐渐减少。Al、Fe与大多数常、微量元素(Si、Ca、Sr除外)呈正相关，Ca、Sr与大多数元素呈负相关，而它们本身呈强正相关。Co、Ni、Zn、Ba、Zr与Cu呈正相关，表现为亲铜性。④本区元素的分布主要受沉积物类型、物质来源、水深和生物生产力的影响。     

淮南张集矿区煤中微量元素的含量分布特征分析

在采用ICP-AES对张集7个煤层144个样品微量元素含量测试分析的基础上,探讨了元素在不同煤层中的变化规律及其在煤层对比中的应用。结果表明:张集矿区煤中元素B、Se和As含量偏高;不同煤层中微量元素含量变化较大,但具有一定的规律性,其中在9煤层中元素Ba和Cr含量最低,Mn、Zn、As和Se含量相对较高,可以利用这些元素分布特征来区别和划分相邻煤层。     

内蒙古拜仁达坝西矿区锌多金属矿床原生地球化学异常模式

拜仁达坝西矿区锌多金属矿床为典型的热液脉型多金属矿床。通过对矿区内岩石中元素富集贫化规律、原生异常分带序列、地球化学参数垂向变化、硫与铁及成矿元素的协同平衡关系等的研究,发现矿床中发育成矿及伴生元素正异常和贫化元素Ba、Sr、Na2O的负异常,矿床整体产于贫化元素形成的亏损晕中;矿床直接指示元素为Zn、Ag、Pb、Cu、Cd、Sb、Hg,间接指示元素为Ba、Sr、Na、As、W、Rb;矿床原生异常轴向分带序列为Ag-Hg-Pb-As-Cd-Zn-Bi-AuCu-Sb-Na2O-Sr-Ba-W-Co-Mo-Rb,出现As、Sb等元素"反分带"现象;元素含量及地球化学参数垂向变化波动较大,反映叠加成矿作用强烈,成矿过程复杂;各类异常特征均显示成矿地球化学系统在矿床深部尚未终止,推测已知矿床深部可能存在隐伏盲矿体。初步构建了矿床原生地球化学异常模式,为矿区深部及外围找矿工作提供了依据。     

A field experiment testing for correspondence between trace elements in otoliths and the environment and for evidence of adaptation to prior habitats

Site-specific variation in the trace element composition of fish otoliths can be used to identify fish to source, but the mechanisms controlling elemental composition are poorly understood. Environmental influences on the deposition of barium (Ba), copper (Cu), manganese (Mn), and strontium (Sr) in the otoliths of mudsuckers (Gillichthys mirabilis) were tested using a reciprocal field transplant experiment, in which fish from 3 estuaries were transplanted to each of the 3 estuaries. Fish originating from the 3 estuaries showed no differences in otolith chemistry that might reflect acclimation to past conditions in their home estuary or genetic differences among populations, which simplifies the interpretation of otolith chemistry. Cu and Mn concentrations in otoliths differed according to the site of transplant. Cu in otoliths showed the same pattern of difference among estuaries as did Cu in sediments, but there was no correspondence between Cu in otoliths and dissolved Cu. Ranked differences among estuaries in otolith Mn matched the ranking of estuary-specific differences in dissolved Mn, and there was no correspondence between the concentration of Mn in otoliths and sediments. Fish transplanted to different estuaries showed no differences in otolith concentrations of Ba or Sr, and the concentrations of Ba and Sr in the water column showed a similar lack of difference among estuaries. This study provides field evidence supporting the conclusion that the elemental composition of otoliths reflects environmental conditions to which fish have been recently exposed, but whether that correlation is with trace elements in the sediment or water column can vary.     

Facilitation of barium uptake into fish otoliths: Influence of strontium concentration and salinity

To reconstruct patterns of fish migration using otolith chemistry, it is essential to validate the relationship between elements in otoliths and the surrounding water, and in particular, how processes such as competition and facilitation among multiple elements influence otolith chemistry. Using a controlled laboratory experiment, juvenile black bream (Acanthopagrus butcheri) were reared in both brackish and seawater spiked with different concentrations of Sr and Ba. The addition of Sr to the solution facilitated the uptake of Ba into otoliths of fish reared in brackish water, but not in seawater. Conversely, Ba did not facilitate nor compete with the uptake of Sr in either brackish or seawater. In brackish water, Sr incorporation into otoliths may create crystal defects within the CaCO₃ matrix, enabling greater incorporation of Ba. Ba:Ca partition coefficients (D_Ba) for brackish and seawater were 0.058 and 0.136, respectively, whereas Sr:Ca partition coefficients (D_Sr) for brackish and seawater were 0.463 and 0.287, respectively. The influence of Sr on Ba incorporation in fish otoliths is important to consider when reconstructing migration histories of fish, especially in brackish water environments.     

Salinity and Temperature Effects on Element Incorporation of Gulf Killifish <Emphasis Type="Italic">Fundulus grandis</Emphasis> Otoliths

Many applications of otolith chemistry use the ratios of strontium (Sr) and barium (Ba) to calcium (Ca) as indicators of salinity exposure, because typically, as salinity increases, Sr concentration increases and Ba concentration decreases. However, these relationships are nonlinear, can be confounded by temperature, and investigations of salinity and temperature effects on otolith chemistry produce varied results. To determine the relationships of temperature and salinity on Sr:Ca and Ba:Ca in otoliths, we used free ranging Gulf Killifish (Fundulus grandis) in the northern Gulf of Mexico. This species is ideal because it is euryhaline and exhibits limited movements. Otolith edge Sr:Ca and Ba:Ca ratios were related to the previous 30-day mean salinity and temperature experienced by fish. The best model to describe otolith Sr:Ca was one that included a positive asymptotic relationship for both salinity and temperature. However, the salinity asymptotic maximum was reached at 10 psu and changes in otolith Sr:Ca above 10 psu were indicative of temperature changes. Otolith Ba:Ca exhibited an exponential decreasing relationship with salinity, and an exponential increasing relationship with temperature, and these two models combined best explained otolith Ba:Ca. Above 10 psu, the modeled Ba:Ca ratio continued to decrease demonstrating that this ratio may be indicative of salinity changes beyond this value. Therefore, using both Sr:Ca and Ba:Ca could be beneficial in reconstructing fish environmental histories. Temperature effects on otolith element ratios could confound past salinity reconstructions as well and must be a result of endogenous processes, given that no relationship between temperature and water chemistry existed.     

Analysis of geological Sr isotope markers in fish otoliths with subannual resolution using laser ablation-multicollector-ICP-mass spectrometry

In this pilot study, laser ablation-multicollector-inductively coupled plasma-mass spectrometry (LA-MC-ICP-MS) and Sr isotope geochemistry were applied to fish life-history studies through the micro-analysis of Sr abundance and ⁸⁷Sr/⁸⁶Sr in the otoliths of an anadromous fish. With a laser sampling area of 70-µm diameter, LA-MC-ICP-MS of a deep-sea coral gave precision values for ⁸⁷Sr/⁸⁶Sr determination of approximately 0.04% relative standard deviation with an accuracy to <1C of seawater. Analyses of different sides of the same otolith and different otoliths from the same fish gave reproducible results overall, which suggested that at the Sr concentrations found in the freshwater portions of the otoliths (ca. 500 µg/g) LA-MC-ICP-MS can be reliably employed. Subtle isotopic differences occurred between a pair of otoliths from one fish, which may be due either to sampling resolution limitations imposed by the size of the laser spot, or to asymmetrical otolith growth which incorporated environmental Sr in one otolith but not the other at certain times. New information about fish provenance which could not be gained from Sr concentration data alone included insights into the movements of individuals between isotopically contrasting freshwater environments. LA-MC-ICP-MS of calcified tissues, in combination with Sr isotope geochemistry, has the potential to retrieve new data about fish life-history movements which complement the information from other techniques.     

Inter-annual variability in isotope and elemental ratios recorded in otoliths of an anadromous fish

Isotope ratios and elemental concentrations in otoliths are often used as natural tags to reconstruct migratory movements and connectivity patterns in marine and anadromous fishes. Although differences in otolith geochemistry have been documented among geographically separated populations, inter-annual variation within locations is less frequently examined. We compared otolith isotope (δ¹⁸O and ⁸⁷Sr:⁸⁶Sr) and elemental ratios (Sr:Ca and Ba:Ca) from several annual cohorts of juvenile American shad (Alosa sapidissima) in three rivers. These four geochemical signatures distinguished among river-specific populations of this species at both large and small geographic scales, with δ¹⁸O and ⁸⁷Sr:⁸⁶Sr generating the majority of multivariate variation. We found significant variation among years for all variables in two to three rivers. However, the magnitude of variability differed among ratios, with δ¹⁸O ratios showing substantial inter-annual shifts while ⁸⁷Sr:⁸⁶Sr ratios were relatively stable across years. Sr:Ca and Ba:Ca ratios also varied among years. These results imply that investigators using environmentally labile signatures must quantify geochemical signatures for each cohort of interest in order to confidently identify origins of migrants.