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1.
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 (DBa) for brackish and seawater were 0.058 and 0.136, respectively, whereas Sr:Ca partition coefficients (DSr) 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.  相似文献   

2.
不同水域鲤鱼耳石微化学特征及其环境指示意义   总被引：6，自引：0，他引：6  
利用中子活化分析对密云水库与白洋淀水域两个不同水域（无污染水域和重污染水域）中鲤鱼耳石的微量元素进行分析，发现白洋淀鲤鱼耳石中Sr、Zn、As、Au、Ba、K、Na的含量明显比密云水库鲤鱼耳石的相应元素含量高。采用线性判别方法对两地耳石中Sr、Zn、As、Ba4种元素进行分析，表明存在明显的分组差异，而且两地的差别主要在于Sr含量不同，其次是Zn、As和Ba；白洋淀鲤鱼耳石中As、Ba、Sr、Na等元素含量变化幅度比密云水库鲤鱼耳石中相应元素含量的变化幅度大，与白洋淀水域废水排放时间上的周期性和短暂性导致元素在耳石部分日轮上沉淀等因素相吻合。两地鲤鱼耳石微量元素特征存在截然的区别，与两地水域水体中微量元素差异相一致，表明鲤鱼耳石微化学特征具有水化学环境指示意义，为进一步研究利用鲤鱼耳石进行水化学环境监测或恢复鲤鱼生长期水环境特征奠定了基础。  相似文献   

3.
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.  相似文献   

4.
Estuarine recruitment of fishes is a potential bottleneck in the life cycle of many coastal species. We investigated patterns of size-at-ingress for larval and post-larval California halibut entering the Punta Banda Estuary (PBE), Mexico, using both otolith geochemistry and carbon stable isotope ratios (SIR). Juvenile halibut (n?=?126; 38–163 mm standard length [SL]) were collected from inside PBE and the adjacent exposed coast during the fall of 2003, and otoliths (geochemistry) and muscle tissues (SIR) were analyzed to reconstruct the environmental histories of individuals. Based on geochemical analyses, nearly all fish collected from PBE were characterized by a non-estuarine signature (e.g., low Mn and Ba) in the otolith growth bands deposited when fish were <30 mm SL. Although fish collected from the coast retained that signature throughout their lives, fish collected within PBE showed elevated concentrations of Mn and Ba in the otolith growth bands deposited once halibut were 30–70 mm SL, thereby recording ingress. Carbon SIR of juvenile halibut prey also differed between the estuary and coast. Muscle δ 13C values of halibut captured along the coast were consistent (ca.?15‰), while those captured in the estuary were variable and generally more enriched in 13C (?16‰ to ?11‰). Both natural tagging approaches agreed that most halibut (~75 %) enter PBE long after settlement (>?>?8–12 mm SL), although size-at-ingress estimates were significantly larger (mean difference = 27 mm; p?<?0.001) when derived via carbon SIR than with otolith geochemistry. Potential explanations for the differences in size-at-ingress estimates involve the magnitude of isotopic and trace element gradients at this ocean–estuary boundary, the temporal resolution of environmental tags stored within otoliths and soft tissues, and the size-at-capture or somatic growth rate of juvenile halibut. We conclude by discussing the relative merits of otolith geochemistry and SIR as natural tags, and by considering the implications of secondary dispersal into estuaries by post-larval fish.  相似文献   

5.
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.  相似文献   

6.
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.  相似文献   

7.
Transition and heavy metals within the calcified otoliths of estuarine fishes may represent valuable tracers of environmental exposures, allowing inferences on natality, habitat use, and exposure to pollution. Accurate measurement of very low concentrations of these metals in otoliths by inductively coupled plasma mass spectrometry (ICP-MS) is often precluded by the interferences of predominant calcium matrix. We coupled a solid phase extraction procedure to an ICP-MS instrument to overcome the matrix problems and improve the limits of detection. To test this novel application and the utility of otolith transition and heavy metals as tracers of habitat use, otoliths of American eel (Anguilla rostrata) captured from 6 locations (George Washington Bridge, Haverstraw, Newburgh, Kingston, Athens, and Albany) throughout the Hudson River estuary were analyzed for site specific differences expected due to varying environmental exposure. Several trace elements, including Al, Bi, Cd, Co, Cu, Ga, Mn, Ni, Pb, V, and Zn, were selectively extracted from otolith solutions and preconcentrated on a microcolumn of chelating resin. The concentrations of all elements inA. rostrata otoliths were above the limits of detection that ranged from 0.2 ng g?1 for Co to 7 ng g?1 for Zn. Differences in the elemental composition of the otoliths among the groups were significant indicating different levels of exposure to environmental conditions. Discriminant analysis yielded an overall location classification rate of 78%. Al, Bi, Cd, Mn, Ni, and V contributed most to the discriminant function. Samples collected at George Washington Bridge showed 100% discrimination from other locations, and higher levels of many transition and heavy metals, consistent with higher exposure to these metals in the most polluted region of the Hudson River estuary.  相似文献   

8.
In 1998, a 59-cm sediment box core (PLB98-2) was taken from the deepest part of Pyramid Lake (water depth =106 m), Nevada. Age control for PLB98-2 was provided using a variety of approaches. Dried sediment samples were leached with 10% ultra-pure nitric acid and analyzed for their elemental concentrations using standard ICP techniques. The variations in elemental concentrations can be divided into two periods: one prior to European settlement and one influenced by anthropogenic activities. The concentrations of K, Al, Na, Zn, and Mn all began to increase after pre-European manipulation of the watershed in ~1860, which indicates the increasing soil erosion in the watershed was due to deforestation and development. The highest concentrations of these elements and lithogenic elements such as P, Mg, Fe, Cu, Ba, and Si occurred during the flood event of the 1990s. The Pb enrichment times are similar to what has been observed in estuaries draining the western Sierra Nevada, but the Pb enrichments in Pyramid Lake are much less. The Ca, TOC, TIC, Sr, and Ba concentrations show a strong association that is closely related to drought-wet variations of climate and the construction of Derby Dam for water diversions in the early 1900s. Se concentrations vary with the '18O of the carbonate in the sediments. Although the '18O "leads" the other species and Truckee River discharge by a few years, it is an excellent indicator of the hydrological change of Pyramid Lake, which is related to climate changes and human activities. From ~1920, Mn and Mo vary inversely in the sediments. In general, the Mo concentrations varies directly with the organic carbon content of the sediments from 1910 to ~1980, suggesting enhanced removal of Mo during times of increased productivity in the lake, and anoxic conditions at the sediment/water interface. This coincides with low lake levels. The elemental composition of the sediments in Pyramid Lake clearly reflect the timing of important anthropogenic activities and climatic variations that have taken place within the watershed over the past 240 years.  相似文献   

9.
The Pliocene aquifer receives inflow of Miocene and Pleistocene aquifer waters in Wadi El Natrun depression. The aquifer also receives inflow from the agricultural activity and septic tanks. Nine sediment samples were collected from the Pliocene aquifer in Wadi E1 Natrun. Heavy metal (Cu, Sr, Zn, Mn, Fe, Al, Ba, Cr, Ni, V, Cd, Co, Mo, and Pb) concentrations of Pliocene aquifer sediments were investigated in bulk, sand, and mud fractions. The determination of extractable trace metals (Cu, Zn, Fe, Mn, and Pb) in Pliocene aquifer sediments using sequential extraction procedure (four steps) has been performed in order to study environmental pathways (e.g., mobility of metals, bounding states). These employ a series of successively stronger chemical leaching reagents which nominally target the different compositional fractions. By analyzing the liquid leachates and the residual solid components, it is possible to determine not only the type and concentration of metals retained in each phase but also their potential ecological significance. Cu, Sr, Zn, Mn, Fe, and Al concentrations are higher in finer sediments than in coarser sediments, while Ba, Cr, Ni, V, Cd, Co, Mo, and Pb are enriched in the coarser fraction. The differences in relative concentrations are attributed to intense anthropogenic inputs from different sources. Heavy metal concentrations are higher than global average concentrations in sandstone, USEPA guidelines, and other local and international aquifer sediments. The order of trace elements in the bulk Pliocene aquifer sediments, from high to low concentrations, is Fe?>?Al?>?Mn?>?Cr?>?Zn?>?Cu?>?Ni?>?V?>?Sr?>?Ba?>?Pb?>?Mo?>?Cd?>?Co. The Pliocene aquifer sediments are highly contaminated for most toxic metals, except Pb and Co which have moderate contamination. The active soluble (F0) and exchangeable (F1) phases are represented by high concentrations of Cu, Zn, Fe, and Mn and relatively higher concentrations of Pb and Cd. This may be due to the increase of silt and clay fractions (mud) in sediments, which act as an adsorbent, retaining metals through ion exchange and other processes. The order of mobility of heavy metals in this phase is found to be Pb?>?Cd?>?Zn?>?Cu?>?Fe?>?Mn. The values of the active phase of most heavy metals are relatively high, indicating that Pliocene sediments are potentially a major sink for heavy metals characterized by high mobility and bioavailability. Fe–Mn oxyhydroxide phase is the most important fraction among labile fractions and represents 22% for Cd, 20% for Fe, 11% for Zn, 8% for Cu, 5% for Pb, and 3% for Mn. The organic matter-bound fraction contains 80% of Mn, 72% of Cu, 68% of Zn, 60% of Fe, 35% of Pb, and 30% of Cd (as mean). Summarizing the sequential extraction, a very good immobilization of the heavy metals by the organic matter-bound fraction is followed by the carbonate-exchangeable-bound fraction. The mobility of the Cd metal in the active and Fe–Mn oxyhydroxide phases is the highest, while the Mn metal had the lowest mobility.  相似文献   

10.
Selenium and heavy metals content in some Mediterranean soils   总被引：1，自引：0，他引：1  
The study of metal contents in industrial, agricultural or/and polluted soils compared with natural or unpolluted soils is currently necessary to obtain reference values and to assess soil contamination. Nonetheless, very few works published appear in international journals on elements like Se, Li and Sr in Spanish soils. This study determines the total levels of Se, Li, Sr, As, Cd, Co, Cr, Cu, Ni, Pb, V, Zn, Fe, Mn and Ba in 14 natural (unpolluted) soils (Gypsisols, Leptosols, Arenosols and Acrisols), 14 agricultural soils (Anthrosols, Fluvisols and Luvisols), and 4 industrial–urban affected-surface soil horizons (Anthrosols and Fluvisols) of Eastern Spain. The geochemical baseline concentrations (GBC) and reference values (RV) have been established, and the relationships among elements and also between soil properties and elemental concentrations have been analysed. The RV obtained in this study were (mg kg−1): Se 2.68, Li 115, Sr 298, Cd 0.97, Co 35, Cr 217, Cu 46, Ni 50, Pb 137, V 120, Zn 246, Fe 124,472, Mn 2691, and Ba 743. The RV for Se and Li were used as a preliminary approach to assess soil contamination in Spanish soils. The results confirm human impact on Sr, As, Cd, Cr, Cu, Ni, Pb and Zn soil concentrations, but evidence no deviation from natural Se, Li, Co, V, Fe, Mn and Ba concentrations. The results obtained from the statistical analysis reveal significant correlations between some elements and clay and soil organic matter (SOM) contents, indicating that metal concentrations are controlled by soil composition. One particularly interesting finding is the high correlation coefficients obtained between SOM and Se, Cd, Cr, V, Fe, and Mn, and between clay and Cd, Zn, V, Fe and Mn. Once again, these facts confirm the role of SOM and clay minerals in soil functions and that soil is an ecosystem element responsible for maintaining environmental quality.  相似文献   

11.
 Sediment geochemistry of a shallow (6-m average) reservoir (Lake Waco) was evaluated for the spatial distribution of major and trace elements. Sixty bottom and core samples along a 21-km transect within the reservoir, 18 overbank sediment samples, and 8 rock types in the drainage area were collected and analyzed for major (Al, Ca, Fe) and trace elements (As, Ba, Cr, Cu, Hg, Mn, Ni, Pb, Sr, V, Zn). Elemental concentrations in the reservoir sediments closely correspond to concentrations in the regional rocks and represent a mixture of overbank sediment composition of the tributaries. Elemental concentrations were statistically regressed against Al concentrations in order to establish regional baseline levels and thereby distinguish natural from anthropogenic sources. Spatial geochemical trends, considered in terms of element-to-Al ratio versus V-to-Al ratio, relate to the natural and anthropogenic sources contributing to the elemental concentrations. The spatial elemental distribution in the reservoir, which receive sediments from two mineralogically contrasting basins, reflect textural and mineralogical transition within the reservoir and suggest a progressive mixing of sediment from the tributaries. The spatial elemental distribution and sediment texture suggest that the sediment-source, which determines the sediment-type, has a greater influence on the major- and trace-element distributions in shallow reservoir sediments than bathymetry. Received: 25 September 1997 · Accepted: 3 February 1998  相似文献   

12.
A sequential extraction procedure applied to surface sediments from El Kelbia Lagoon determined the partitioning of Ba, Co, Cr, Cu, Ni, Sr, V and Zn among evaporites, carbonates, Fe–Mn oxides, organic matter and silicates. To validate the procedure, the sequential extraction results (SER) were compared to principal components analysis (PCA) using major and trace element concentrations and mineralogical quantitative data of surface sediments. SER showed that a part of Sr was highly mobile; Cu, Sr, and Zn and a part of Co and Ni were mobile depending on pH conditions; Cr and V were strongly bound to silicate phases; Co and Ni were partitioned between carbonates, oxides and silicates, and a great part of Ba and Sr were bound to organic matter or sulfides. An agreement was found with PCA in terms of partitioning among minerals for most trace elements. Moreover, the absence of correlation between Ca concentrations and the abundances of calcite, gypsum or dolomite could be explained by an important fraction of Ca bound to organic matter. Also, unexpected negative correlations between abundances of smectite and illite could be explained by a transformation of illite into smectite. Thus, SER and PCA were mostly convergent, which enabled: (1) validation of the extraction procedure used, and (2) refinement of interpretations of the origin and relations between minerals.  相似文献   

13.
The absolute concentrations of minor and trace elements vary considerably in plankton. However, normalization of elemental abundances versus the minor elements Fe, Al and Zn (instead of the commonly used normalization versus seawater concentrations) demonstrates that these elements show remarkably constant proportions vis à vis each other. Thus, Ti, Fe, Al, Mn, V, and Zr occur in marine lower organisms in the same proportions as in the average shale, whereas Ba, Cr, Cu, Ni, Cd, Pb, Zn and B are enriched relative to the shale abundances, as are also Ca, Mg, Na, K, and Sr. These patterns appear to suggest that marine plankton are rich in lithogenic matter, but this is probably not the normal case.Contrary to the uniformity of plankton, sediments from the Pacific vary considerably in composition. Under the Equatorial high-productivity region the sediments show striking similarities with a mixture of average shale and average plankton mass, as could be expected, whereas sediments from the East Pacific Rise differ considerably from such mixtures. An iron—manganese phase (of deep-seated origin?), mixed with biological matter, on the other hand, yields model sediments with remarkable similarities to the East Pacific Rise deposits. It is therefore likely that biological processes account for a considerable fraction of some elements such as Cu, Ni, Zn and Ba also in the East Pacific Rise metalliferous sediments.  相似文献   

14.
元素地球化学是沉积物源判别和环境研究的重要手段,但河口海岸地区沉积动力环境复杂多变,人类活动影响强烈,全岩沉积地球化学的示踪研究存在局限性和多解性。选择长江下游干流悬浮物、东海陆架表层沉积物以及长江口具有一百多年沉积记录的ZK6孔,通过化学相态分析（1 N HCl处理）,探究酸溶态微量元素组成特征及其对河口环境变迁的指示。相较于钻孔全岩样品,酸溶态Sr/Ba比能更可靠地反映河口古盐度和海陆相沉积环境的变化。ZK6孔沉积物酸溶态稀土元素（REE）主要赋存于Mn氧化物中,Mn、ΣREE含量、Ce/Ce*以及Sr/Ba比在1899—2007年间呈三段式变化,主要反映长江河口流路分汊和主泓位置改变引起的河口沉积环境变化,进而影响河口环境中活跃元素和次生组分在沉积地层中的保存记录。该研究对今后深化认识复杂河口环境下微量元素地球化学行为以及微量元素示踪海洋环境变化具有借鉴意义。  相似文献   

15.
Surface sediments from the Jizan shelf, southern Red Sea, were analysed for grain size and mineralogical and elemental composition in order to establish their geochemical characteristics. Texturally, sediments are classified into sand and mud; the latter dominates the shelf. Grain size variability and mineralogical assemblages present in the sediments largely control the abundance and distribution of CaCO3, organic carbon content (OC) and the major and trace elements. Sand sediments are composed of carbonate material of marine origin and contain high concentrations of Ca, Mg and Sr. Mud sediments are relatively rich in OC and are characterised by high concentrations of Al, Fe, Ti, Mn, Cu, Cr, Co, Ni, V and Ba. Unlike the sand, Mg concentration in the mud sediments seems to be controlled by stronger contribution from non-carbonate material. Factor analysis is applied to identify the variables accounting for most of the variance in the mud sediment samples. Three factors are found to describe about 78% of the variance. The first factor which accounts for 41% of the total variance is the Fe and Mn oxides that reach the area through episodic flooding. The second and third factors are the mud (22%) and the mineralogy (15%) of the sediments, respectively.  相似文献   

16.
Submarine groundwater discharge (SGD) is an important source of dissolved elements to the ocean, yet little is known regarding the chemical reactions that control their flux from sandy coastal aquifers. The net flux of elements from SGD to the coastal ocean is dependent on biogeochemical reactions in the groundwater-seawater mixing zone, recently termed the “subterranean estuary.” This paper is the second in a two part series on the biogeochemistry of the Waquoit Bay coastal aquifer/subterranean estuary. The first paper addressed the biogeochemistry of Fe, Mn, P, Ba, U, and Th from the perspective of the sediment composition of cores Charette et al. [Charette, M.A., Sholkovitz, E.R., Hansell, C.M., 2005. Trace element cycling in a subterranean estuary: Part 1. Geochemistry of the permeable sediments. Geochim. Cosmochim. Acta, 69, 2095-2109]. This paper uses pore water data from the subterranean estuary, along with Bay surface water data, to establish a more detailed view into the estuarine chemistry and the chemical diagenesis of Fe, Mn, U, Ba and Sr in coastal aquifers. Nine high-resolution pore water (groundwater) profiles were collected from the head of the Bay during July 2002. There were non-conservative additions of both Ba and Sr in the salinity transition zone of the subterranean estuary. However, the extent of Sr release was significantly less than that of its alkaline earth neighbor Ba. Pore water Ba concentrations approached 3000 nM compared with 25-50 nM in the surface waters of the Bay; the pore water Sr-salinity distribution suggests a 26% elevation in the amount of Sr added to the subterranean estuary. The release of dissolved Ba to the mixing zone of surface estuaries is frequently attributed to an ion-exchange process whereby seawater cations react with Ba from river suspended clay mineral particles at low to intermediate salinity. Results presented here suggest that reductive dissolution of Mn oxides, in conjunction with changes in salinity, may also be an important process in maintaining high concentrations of Ba in the pore water of subterranean estuaries. In contrast, pore water U was significantly depleted in the subterranean estuary, a result of SGD-driven circulation of seawater through reducing permeable sediments. This finding is supported by surface water concentrations of U in the Bay, which were significantly depleted in U compared with adjacent coastal waters. Using a global estimate of SGD, we calculate U removal in subterranean estuaries at 20 × 106 mol U y−1, which is the same order of magnitude as the other major U sinks for the ocean. Our results suggest a need to revisit and reevaluate the oceanic budgets for elements that are likely influenced by SGD-associated processes.  相似文献   

17.
Significant differences are noticed in major and trace element compositions between the Yangtze River and the Yellow River surface sediments.The former sediments are rich in some major elements such as K,Fe,Mg,Al,and most of the trace elements which show wide variations in element concentrations,whereas the Yellow River sediments only have higher Ca,Na,Sr,Ba,Th,Ga,Zr,Hf contents and show slight variations in element contents.In the Yangtze River Basin are widely distributed intermediate-acid igneous rocks and complicated source rocks together with strong chemical weathering which determine the elemental compositions of the Yangtze River sediments,while the elemental compositions of the Yellow River sediments are decided by the chemical composition of loess from the Loess Plateau and intense physical weatering.Cu,Zn,Sc,Ti,Fe,V,Ni,Cr,Co,Li and Be can be used to distinguish the Yangtze River sediments from te Yellow River sediments and be treated as tracers for both the sediments to study the processes of their mixing and diffusion in the coastal zones of China.  相似文献   

18.
We investigated whether the otolith chemistry ofHaemulon flavolineatum (French grunt), a nocturnally active fish, could be used as a means to differentiate individuals occupying mangrove and coral reef habitats. In 2003, adults were collected from 9 mangrove and 10 coral reef sites throughout Turneffe Atoll, Belize. Concentrations of trace elements were measured at the edge of sagittal otoliths by laser ablated inductively coupled plasma mass spectrometry. Results of a two-factor nested MANCOVA (sites nested within habitat and covariate of fish size), used to investigate whether significant differences in otolith elemental concentrations existed between habitats (i.e., mangrove versus reef) and among sites, indicated significant differences between habitats, in terms of lithium, magnesium, zinc, and rubidium (fish from mangroves had greater concentrations than those from coral reefs), as well as among sites (for several elements). Because elemental variability existed between habitats and among sites, we asked whether this variability was sufficient to differentiate habitats and sites using separate linear discriminant function analyses (LDFA). LDFA indicated that fish were classified to the habitat (mangrove or reef) from which they were collected with a moderate degree of accuracy (correct classification of 74% and 79% for mangrove and coral reef fish, respectively), but were poorly classified to the site from which they were collected (average correct classification of 46% with a range of 0–89%). Otolith microchemical investigations ofH. flavolineatum at Turneffe Atoll can be used to identify movement between habitats, yet due to the lack of unique site-specific chemical signatures likely caused by the nocturnal movement of individuals, it will not be possible to identify specific sites from which reef fish originated.  相似文献   

19.
Southern flounder Paralichthys lethostigma is a recreationally and commercially important species along the western Atlantic and northern Gulf of Mexico coasts that can exhibit complex early-life habitat-use patterns. Herein, we used an otolith microchemical approach to test the conventional wisdom that juvenile southern flounder spend most of their early life in low-salinity areas of estuaries, focusing on the largely unstudied population in the Mobile-Tensaw Delta, AL. Analysis of strontium/calcium concentrations in otolith cores of age 0 juveniles demonstrated that 68% of these individuals hatched in high-salinity waters before moving into freshwater habitats, with the remaining individuals being spawned in or near freshwater habitat. Further, otolith edge Sr/Ca concentrations revealed that even juveniles used freshwater habitats, particularly during freshwater/oligohaline conditions in our study system. Otolith edge Sr/Ca ratios for fish collected during high-salinity periods differed significantly among collection regions, suggesting seasonal differences in patterns of habitat use between individuals collected upstream (i.e., freshwater habitats) vs. downstream (i.e., euryhaline habitats). These data support the hypothesis that early-life stages of a substantial portion of a coastal southern flounder population use freshwater habitat.  相似文献   

20.
Estuarine tapertail anchovy (Coilia nasus) is a highly commercial and valuable anadromous fish species in China. Due to the complex anadromous life cycle, it remains difficult to assess the degree of connectivity among groups of C. nasus in the Yangtze River, its connecting lakes, and adjacent seas. In this study, laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) was used to analyze the element composition in the otolith nucleus region of C. nasus specimens from the Yangtze River Estuary, Poyang Lake, and Nantong coastal waters in the estuary adjacent to the Yellow Sea. The content ratios of seven elements (Na, Mn, Fe, Ni, Cu, Sr, and Ba) to Ca in the nucleus indicated a close relationship among C. nasus specimens collected from the Yangtze River Estuary (Spring group), Poyang Lake, and Yellow Sea, suggesting a possible connectivity mechanism for anchovies in the three water bodies. Poyang Lake, Yangtze River, and Yellow Sea seem to be the natal lake, migration pathway, and feeding ground, respectively.  相似文献   

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