Vertical Migration Process Research Articles

Interpretation of vertical migration and enrichment processes of rare earth elements (REEs) in ion-adsorption-type mineralization in Japan based on REE speciation analyses

Typical vertical profiles of ion-adsorption-type rare earth element (REE) deposits discovered in southwest Japan were studied by conducting speciation analyses, including X-ray absorption fine structure and laser-induced fluorescence spectroscopy combined with transmission electron microscopy and adsorption/desorption experiments. The results revealed that REE speciation, migration, and enrichment in weathered granite is largely controlled by soil pH, which in turn controls the variable charges of kaolinite, the REE host phase. Both the distribution coefficient Kd and the soil pH increase with depth. As a result, (i) REE dissolution and migration occur in the near-surface acidic environment of the upper layers, where hydroxyls of kaolinite basal surfaces and edges are deprotonated to a lesser degree, and (ii) REEs accumulate in the relatively high-pH environment below the surface, where hydroxyls of kaolinite basal surfaces and edges are deprotonated to a larger degree, producing REE adsorption sites with variable charges. An increase of soil pH to greater than 6 in deeper layers promotes inner-sphere complexation of REEs. Although inner-sphere complexation inhibits the ion-exchange extraction of REEs, the inner-sphere complexes can be still extracted by lowering the pH of the extraction solution. This fact, which indicates that the adsorption of both inner- and outer-sphere complexes is reversible, is important in terms of both (i) understanding vertical REE profiles in which the pH varies and (ii) the efficient recovery of REEs from REE-enriched layers at all depths in weathered granite.

The integration of diel vertical migration and hydrodynamic process influences the transport of swimming crab zoea (Portunus trituberculatus)

AbstractVertical migration and dispersal processes during the marine crab larval stage markedly affect transport, habitat selection, population connectivity, and resource replenishment success rates. However, not much is known of the reproductive ecology of swimming crabs in the nearshore waters of the northwest Pacific shelf. Here, we investigated the diel vertical migration (DVM) characteristics and transport patterns of the swimming crab zoea (Portunus trituberculatus) in this area. A Lagrangian particle‐tracking algorithm coupled with a hydrodynamic model, incorporating a DVM pattern of zoeae based on observations from a field survey of the diurnal distribution of swimming crab zoea, was used to simulate the transport of zoeae, and the impact of zoeal transport on population connectivity was explored. The results revealed that particles were predominantly transported in a nearshore direction from the particle release point, with short dispersal distances during the zoeal stages. In nearshore waters on the continental shelf, the swimming crab zoeae are exposed to shoreward‐moving currents with the aid of prolonged daytime locations in the lower water column, whereas larvae migrate upward to the middle and upper layers of the water column at night rather than the most superficial layer, potentially avoiding surface offshore‐moving currents that may be responsible for the retention and shoreward transport of larvae. Most zoeae are transported to shallow waters, and the contribution of transport to population connectivity during the zoeal stages is relatively limited. The findings here have considerable implications for understanding the mechanisms governing the early recruitment dynamics of this species, as well as for fisheries management and conservation of marine biodiversity.

High trophic level feedbacks on global ocean carbon uptake and marine ecosystem dynamics under climate change.

Despite recurrent emphasis on their ecological and economic roles, the importance of high trophic levels (HTLs) on ocean carbon dynamics, through passive (fecal pellet production, carcasses) and active (vertical migration) processes, is still largely unexplored, notably under climate change scenarios. In addition, HTLs impact the ecosystem dynamics through top-down effects on lower trophic levels, which might change under anthropogenic influence. Here we compare two simulations of a global biogeochemical-ecosystem model with and without feedbacks from large marine animals. We show that these large marine animals affect the evolution of low trophic level biomasses, hence net primary production and most certainly ecosystem equilibrium, but seem to have little influence on the 21st-century anthropogenic carbon uptake under the RCP8.5 scenario. These results provide new insights regarding the expectations for trophic amplification of climate change through the marine trophic chain and regarding the necessity to explicitly represent marine animals in Earth System Models.

Vertical Migration Process of 137cs and 60co in Soil and its Potential Hazard on Groundwater Under Different Scenarios Simulation

Vertical Migration Process of 137cs and 60co in Soil and its Potential Hazard on Groundwater Under Different Scenarios Simulation

New insight into the response and transport of nitrate in karst groundwater to rainfall events

Although numerous studies focused on nitrate source, transformation and transport of river water in karst area have been reported, it's still unclear in understanding nitrate main source and transformation in karst groundwater system and how nitrate transport from soil to water during rainfall events in karst critical zone. In order to explore the response and transport of nitrate in karst groundwater to rainfall events, different depths of well water before, during and after rainfall event were sampled, and hillslope runoff, surface runoff of different land-use types during rainfall event were sampled synchronously at a typical karst agricultural catchment in Southwest China. Results showed that fluctuations of EC, pH and DO in deep borehole well (W1) and artesian well (W2) were small, on the contrary, variations of EC and DO in shallow well (W3) were large during sampling period. The nitrate concentrations and isotopic values indicated that nitrate in karst groundwater mainly originated from chemical fertilizer (CF), and influenced by denitrification process. High intensity of denitrification was observed in deep groundwater (87%) and artesian well water (almost 100%). Extremely high dual nitrate isotope values up to 46.8 ± 1.5‰ and 24.7 ± 0.5‰ were found in the deep artesian well. The small variation of water chemistry (EC, DO and pH), nitrate concentration and dual nitrate isotope values in deep wells during sampling period suggested that newly supplied nitrogen in deep groundwater during rainfall events also comes from deep groundwater. Low nitrogen concentrations in hillslope subsurface flow and surface runoff suggests that nitrogen transport process leading to increase of water nitrogen content mainly occur in depression. Nitrogen in depression soil is mainly transported to groundwater through fissures, fractures and conduits, rather than through vertical migration processes in the soil during rainfall events.

Comparative Geochemical Characterization of Heavy Oil with Various Genesis

Oils from Nizhne-Karmal (Tatarstan, Russia) and Boca de Jaruco (Cuba) reservoirs had been researched by GC-MS. Distributions of alkanes, steranes, hopanes, alkylbenzenes had been used as biomarker characteristics. Initial organic substances of both samples had been formed in sea conditions, what had proved by ratio of pristine to phytane. Lack of steranes in Cuban oil evidence about vertical migration or biodegradation processes. Anaerobic microbiological degradation had caused the absence or partial destruction of saturated hydrocarbons. The maturity of raw materials had been estimated by the ratio Ts/(Ts + Tm). Low value Aryl Isoprenoid Index (AIR) showed stability of photic zone for Nizhne-Karmal oil. Photic zone in Cuban reservoir was subjected to the mixing water column.

The geochemical characteristics, origin, migration and accumulation modes of deep coal-measure gas in the west of Linxing block at the eastern margin of Ordos Basin

The deep coal-measure gas, including coalbed methane (CBM), tight gas (TG) and shale gas (SG), has attracted widely attention because of its great potential for natural gas development and multiple benefits. To determine the gas origin, migration and evolution in the west of Linxing block, 56 coal-measure gas samples from different horizons and depth were collected. The gas components and stable isotope compositions were measured, and the results show that methane is the main composition of coal-measure gas, distributed between 78.83% and 96.67%. The average carbon dioxide and nitrogen concentrations are 1.99 and 1.56 vol %, respectively. Coal-measure gas has apparent dry and wet gas coexist characteristics, with drying coefficient values ranging from 0.821 to 0.989. The δ13C(CH4) and δD(CH4) are between −41.81‰ and −26.65‰ and −224.1‰ to −180.5‰, with an average value of −36.23‰ and −206.5‰, respectively. The coal-measure gas in the study area is mainly coal-type gas mixed with a small amount of oil-type gas. The gas origin is mainly thermogenic, and in Benxi Formation and Taiyuan Formation there is inorganic CO2 due to the magma intrusion. The vertical and lateral migration processes of natural gas were observed controlled by dynamic isotope fractionation effect and migration fractionation effect. Based above results, two types of reservoir forming modes of natural gas, i.e., “near-source reservoir-forming mode” and “lower-source rock generation, upper-reservoir storage mode” were established. The process of gas accumulation has experienced four evolution stages. The comparative analysis of our data with that of other previously reported study fields, permit a more robust evaluation of the geochemistry, origin, migration, and evolution of deep coal measures gas in this area.

The Calculation and Model Block Diagram of the Surface Cd Content of Haibo River from Land Sources

Applying the survey data of the Cd content in the water of Jiaozhou Bay in October 1992, from the southern waters of the bay mouth to the southeastern waters, the author calculates out the horizontal loss amount, the vertical disputed amount and the vertical sediment amount of the Cd content in the surface and bottom of the water body and determines the model block diagram of the horizontal and vertical changes of Cd content, based on the content changing models of the horizontal matter and the vertical matter proposed by the author himself. The calculation results show that in October, the absolutely horizontal increase amount of Cd content in the surface and bottom layer is 0.12-0.89μg/L, and the relatively horizontal increase amount of Cd content in the surface and bottom layer is 23.52-74.78%. In the southern waters of the bay mouth, the Cd content in the surface and bottom layer has an absolutely vertical disputed amount of 0.09μg/L, and its relatively vertical disputed amount is 23.07%. In the southeastern waters of the bay, the Cd content in the surface and bottom layer has an absolutely vertical sediment amount of 0.68μg/L, and its relatively vertical sediment amount is 57.14%. There is the Haibo River near the southeastern waters of Jiaozhou Bay. In October, the Cd content of the Haibo River is 0.51μg/L, which is higher than the Cd content of 0.39μg/L carried by ocean currents. It provides a lot of supplements to the ocean currents passing the southeastern waters of the bay. During the horizontal migration of the Cd content in the surface and bottom layer, Haibo River supplements the Cd content in the ocean current with the loss and increase of the surface and bottom layer. Through the horizontal changing model of matter content, the horizontal increase of the surface Cd content is calculated. The absolute increase of the Cd content is 0.12μg/L, and the relative increase is 23.52%. Similarly, the horizontal increase of Cd content in the bottom layer is calculated. The absolute increase of Cd content is 0.89μg/L, and the relative increase is 74.78%. During the vertical migration process, the vertical change of the Cd content in the southern waters of the bay mouth and the southeastern waters of the bay reveals the following law: when the surface Cd content is low, the waters present a vertical dilution of the Cd content at the surface and bottom layer, and there is no Cd content accumulation on the seafloor. When the Cd content in the surface layers is high, the waters present a vertical accumulation of Cd content in the surface and bottom layers, and there is an accumulation of Cd content on the seafloor. According to the formula for calculating the Cd content of river sources proposed by author himself, the Cd content of the surface of Haibo River source from land is calculated to be 1.01 μg/L.

Calculation of Loss Amount from Southeast Bay to Southwest Bay

Applying investigation data about Pb in Jiaozhou Bay in August, 1992 and according to horizontal matter content change model and the vertical matter content change model proposed by the authors, the horizontal loss amount, vertical diluted amount and vertical sediment amount of Pb content in the surface and bottom layers from southeast bay to southwest bay are calculated. What’s more, the model diagram of vertical change and horizontal change of Pb content is designed. The calculation results show that in August in 1992, the absolutely loss amount of Pb content in the bottom layer was 11.03μg/L, and the relative loss amount of Pb content in the bottom layer was 58.42%. Meanwhile, the absolutely increase amount of Pb content in the surface layer was 4.60μg/L, and the relatively increase amount of Pb content in the surface layer was 28.93%. In the southeast bay, the relatively vertical sediment amount of Pb content in the surface and bottom layers was 40.14%, and the absolutely vertical sediment amount of Pb content in the surface and bottom layers was 7.58μg/L. Similarly, in the southwest bay, Pb content in the surface layer and bottom layer had an absolutely vertical diluted amount of 8.05μg/L with a relatively vertical diluted amount of 50.62%. In August, the main sea current carried Pb content through the surface nearshore waters around the bay where many sources of Pb content existed. The law of horizontal loss amount shows that: when Pb content migrated horizontally in the surface layer, Pb content did not lose but increased. However, when Pb content migrated horizontally in the bottom layer, a lot of Pb content was lost due to a long distance. Moreover, the law of the vertical loss amount revealed that Pb content was transported by the main sea current and was relatively high in its vertical migration process. As a result, the vertical sediment amount 40.14% of Pb content in surface and bottom layers was changed to the vertical diluted amount 50.62% of Pb content in the surface and bottom layers when the main sea current flowed from southeast bay waters to southwest bay waters.

Profile Distribution and Migration of Heavy Metals in the Soils of the Kursk Agglomeration (Model Experiments)

Aim. Laboratory evaluation of the characteristics of spatial distribution and migration of heavy metals (HM) in model soil profiles of varied genesis through measurement of the electrokinetic potential of soil solutions. Material and Methods. Undisturbed soils of forest parks landscapes and continental floodplain meadows of the Kursk agglomeration were studied. Experiments were carried out in laboratory conditions. The short‐term temporal dynamics were studied of vertical distribution and migration of the introduced HMs in model soil columns which imitated soil profiles. Results. Analysis of the kinetics of soil solutions and of lysimeter waters of control and polluted samples showed that the model profile of typical dark‐gray soil has the least capacity to capture lead ions from polluted soil solutions. Minimum sorption capacity with respect to zinc was found to be characteristic of sod‐podzol illuvialferruginous soil profiles. Maximum ability to deposit the HMs under analysis (Zn and Pb) was shown in leached chernozem medium loamy soils. Conclusion. The dynamics and kinetics of lead and zinc in soils of the Kursk agglomeration differ significantly and depend on a number of soil factors. In the soils studied, the spatial distribution and the intensity of migration of lead and zinc were determined by the capacity and contrast indices of the internal soil geochemical barriers. Inhibition of the processes of vertical migration of Pb and Zn in the model soil profiles was observed in those rich in humusified humus‐accumulative genetic horizons as well as in mineral horizons with highly contrasting acid‐base and redox conditions. Adsorption zones of lead and zinc are formed with a significant increase in granulometric texture and a decrease in pHKCl.

Metal-Bearing Nanoparticles Observed in Soils and Fault Gouges over the Shenjiayao Gold Deposit and Their Significance

Mineral deposits concealed by thick cover sequences present special problems for geochemical exploration. A variety of penetrating geochemical methods have been developed in the last few decades to explore for buried deposits. The theoretical basis of the mechanism by which metals migrate upward from buried deposits through the cover to the surface is still not fully understood. One hypothesis is that metal particles or metal elements could be carried onto bubbles or micro-flow of geogas and migrate upward to the surface. After years of study, nano-scale metal-bearing particles have been widely observed in geogas samples from different kinds of concealed deposits. However, the occurrence of these metal-bearing particles carried by geogases in near-surface media, such as soil, has not been studied in detail. In this study, metal-bearing nanoparticles were observed in samples from soils and fault gouges over the Shenjiayao gold deposit. The results indicate that (1) the ore-forming elements in soils can only come from deep-seated ore bodies and they occur in nanoparticles in the study area; (2) there is an obvious relationship between metal nanoparticles in fault gouges and soils; (3) the metallic nanoparticles in fault gouges represent a transitional phase along the whole vertical migration process. In addition, the observation results show that the metal-bearing nanoparticles tend to be adsorbed on the surface of clay minerals, which provide theoretical support for using fine fraction soils as sampling media to carry out geochemical exploration in sediment-covered terrains. Based on the results and discussion, a simple migration model was built in this paper.

Long-term simulations of radiocesium discharge in watershed with improved radioesium wash-off model: Applying the model to Abukuma River basin of Fukushima

In order to simulate the long-term migration and distribution of radiocesium after the Fukushima accident, a numerical model, Soil and Cesium Transport (SACT) based on universal soil loss equation (USLE), has been developed in previous studies. Although the SACT model's results on radiocesium discharge in 2011 are in reasonable agreement with field measurements, it fails to capture the sharp decrease of radiocesium flux in subsequent years, especially in the case of Abukuma River. The present work aims to improve SACT by implementing new processes for radiocesium wash-off, in which the vertical migration, and long-term fixation of radiocesium in soil are taken in to account. To understand the vertical migration process, depth profile measurement results between 2011 and 2016 have been fitted by different distribution functions and analyzed statistically. A conceptual model has been developed to describe results from recent sorption experiments, which support long-term fixation of radiocesium in soil particles. For validation purpose, the annual average radiocesium concentration in sediments discharged from Abukuma river has been evaluated from measurement data. With these improvements, the new SACT model could achieve much better agreement with the measurement results without parameter tuning.

Yang’s dynamic vertical balance theory: application on Hg’s vertical changes in Jiaozhou Bay

Using investigation on Mercury (Hg) in May and August 1990, this paper analyzed the horizontal and vertical migration changes of Hg contents, and quantified the horizontal loss, vertical dilution and vertical accumulation amounts. Results showed that the absolute horizontal loss amount and relative horizontal loss amount were 0.002-0.015 μg L−1 and 3.63-15.87%, respectively. The absolute dilution amount and relative dilution amount were 0.000-0.005 μg L−1 and 0.00-2.57%, compared to absolute accumulation amount and relative accumulation amount of 0.008 μg L−1 and 12.69%, respectively. Once Hg was transporting through the bay, there were small horizontal losses in both surface and bottom waters. The horizontal loss in bottom waters would be small/big in case of the horizontal loss in surface waters was small/big. No matter Hg contents in waters were relative high or relative low, the sediment of Hg from surface waters to bottom waters was very rapid, and the vertical loss during the vertical migration process was very small, resulting in almost all of the Hg was moving to the sea bottom. Finally, this paper provided Yang’s dynamic vertical balance theory to reveal the vertical migration process of substance in marine bay.

Yang’s Dynamic Vertical Balance Process for the Content of Cd in a Marine Bay

This study analyzes the horizontal and vertical migration processes of Cd contents based on the investigations conducted during May and August 1990. It reveals the dynamic balance process of Cd substance in a marine bay and shows that in the waters close to the source input, the content of Cd in the surface waters is the highest, and also the vertical dilution amount is the highest. This is the beginning of the dynamic vertical balance process. Along with distance from the source input, the sedimentation is an ongoing process, which results in a decrease in the content of Cd in the surface waters, and a reduction in the vertical dilution amount. This process continues to the balance point. In waters far away from the source input, the content of Cd is homogeneous in the waters, and the vertical dilution amount decreases to the lowest value, i.e., the balance point. Furthermore, a block diagram has been provided to demonstrate the dynamic vertical balance process.

Spatial-Temporal Migration of Cd in Marine Bay

This paper quantified the spatial-temporal migration processes of Cadmium (Cd) in Jiaozhou Bay in 1989. Results showed that the horizontal losses of Cd in surface and waters in April 1989 were 37.50% and 16.66%, respectively. The vertical dilution of Cd in the bay center in July 1989 was relatively high i.e. 50.00%. Cd contents in both the surface and bottom waters were decreasing in a certain degree during the horizontal and vertical migration processes. No matter whether it is from the bay center to the bay mouth, or from the bay mouth to the bay centers, Cd contents were decreasing in a certain degree. In case of the rate of loss of Cd in the surface water was relatively high, and the rate of loss of Cd in the bottom water would also be relatively high and vice versa. In April 1989, Cd in the surface waters could be transported to the bottom of sea rapidly and continuously, and the vertical loss of Cd could be as high as 1/3 during the vertical migration process. Furthermore, in July 1989, the vertical loss of Cd was as high as 50.00%, where the vertical losses in Jiaozhou Bay were increasing from 1/3 in April to 1/2 in July. The vertical losses in Jiaozhou Bay were increasing along with an increase in the content of Cd in the surface waters.

Spatio-temporal status and vertical migration features of the settlement processes of Cd in Jiaozhou Bay

Using investigation on Cadmium (Cd) in surfac and bottom waters in this bay during 1984-1988, this paper analyzed the horizontal distributions of Cd, defined that different spatio-temporal status of the settlement processes. Results showed that Cd contents in bottom waters were relative high/low in case of Cd contents in surface waters were relative high/low, and diffference of Cd contents between surface and bottom waters were also relative high/low in case of the Cd contents in surface waters were relative high/low. The diffference of Cd contents between surface and bottom waters were relative low in general. These indicated the settlement processes of Cd from surface waters to bottom waters were very rapid. There were three different status along with the time axis, as well as three different status along with the space axis. Taking time axis as the X-axis and space axis as the Y-axis, the blok diagram model of the nine spatio-temporal status of the vertical migration processes were established. Furthermore, the paper revealed the features of the settlement processes.

Influence of vertical migration process on seasonal variation and horizontal distribution of Pb in marine bay

This paper analyzed the seasonal variation, vertical variation and horizontal distribution of Pb in Jiaozhou Bay using investigation data in April and July 1989. Results showed that Pb contents in surface and bottom waters April 1989 were 9.96-11.03 μg L-1 and 8.15-10.10 μg L-1, respectively, while in July 1989 were 6.47-15.17 μg L-1 and 3.39-7.15 μg L-1, respectively. The pollution level of Pb in bottom waters in April and July 1989 could be considered as heavy and moderate, respectively. The seasonal variations of Hg in both surface and bottom waters were summer > spring. Hence, the seasonal variations of Hg in surface and bottom waters were same. The vertical migration processes of Pb in waters in April and July 1989 revealed the accumulation effect and dilution effect. The seasonal variations of Pb contents in surface waters were determined by the changes of the major Pb sources, while in bottom waters were determined by both the source input and vertical water’s effect. The horizontal distributions of Pb in surface and bottom waters in April 1989 were opposite, yet the horizontal distributions of Pb in surface and bottom waters in July 1989 were consistent. The horizontal distributions of Pb contents in surface waters were determined by the changes of the major Pb sources, while in bottom waters were determined by both source input and the inputting time.

Modeling for horizontal and vertical migration of Pb in marine bay

This paper quantified the horizontal and vertical migration processes of Plumbum (Pb) in Jiaozhou Bay in 1989. Results showed that the horizontal absolute loss amounts of Pb were1.07-8.70 μg L-1, and the horizontal relative loss amounts were 9.70%-57.35%. The vertical absolute dilution amounts of Pb were 1.95-8.70 μg L-1, and the horizontal relative dilution amounts were 19.30%-57.35%. The vertical absolute accumulation amounts of Pb were 1.07 μg L-1, and the vertical relative accumulation amounts were 9.70%. During the migration processes, Pb contents in both surface and bottom waters were decreasing in a certain degree during the horizontal migration process. The horizontal loss amounts were very 52.78%-57.35% in July, yet was very low in April. Meanwhile, the horizontal dilution amounts were also relative high as 47.60%-52.86%. In April, Pb was mainly sourced from river runoff, and there was high sedimentation process in the bay center. In July, Pb was mainly sourced from river runoff and atmosphere deposition, and there were high sedimentation processes in the bay center and the bay mouth.

Influence of Cd contents on the vertical migration process in marine bay

This paper analyzed the contents and distributions of Cadmium (Cd) in Jiaozhou Bay 1989. Results showed that Cd contents in bottom waters in Jiaozhou Bay in April and July 1989 were 0.05-0.06 μg L-1 and 0.06 μg L-1, respectively. The water quality of Cd was meeting Grade I, and the pollution level of Cd was very slight in 1989. The vertical water’s effect was very weak in case of Cd contents in waters were very low, resulting in the vertical migration strength of Cd was very weak, and Cd contents in waters were changing along with the moving of marine current. The vertical water’s effect was strong in case of Cd contents in waters were relative high, resulting in the vertical migration strength of Cd was very strong, and big part of Cd in waters were transporting to sea bottom.

Influencing factors on the horizontal and vertical migration of Cr in marine bay

This paper analyzed the horizontal and vertical migration processes of Cadmium (Cd) and the influencing factors in Jiaozhou Bay in 1989. Results showed that the absolute horizontal losses of Cr were 0.20-0.89 μg L-1, and the relative horizontal losses of Cr were 14.49-46.84%, respectively. The absolute vertical dilution of Cd was 0.52-0.56 μg L-1, and the relative vertical dilution of Cr was 27.36-34.14%. The absolute vertical accumulation of Cd was 0.17 μg L-1, and the relative vertical accumulation of Cr was 14.40%. Once migrating from the bay center to the bay mouth, Contents in both surface and bottom were decreasing in a certain degree. In case of the loss rate of Cr in surface water was relative high, the loss rate of Cr in bottom water would also be relative high, and vice versa. The changing of Cr contents in surface and bottom waters were determined by the changing of the source inputs and the distance of migration paths.