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Resolved measurements of the relative abundances of 13CDH3 and 12CD2H2 from a Taiwan mud volcano confirm that thermogenic CH4 with a formation temperature of 150 °C is bubbling from a pool of liquid mud. Analysis for both doubly-substituted molecules provides confirmation that isotopic exchange equilibrium was achieved between methane isotopologues. Methane extracted from the headspace of core samples taken from sediments deposited proximal to the bubbling pool of mud shows small departures from isotopic equilibrium.

RATIONALE Otoliths are usually used to estimate the age of fish and the chemical composition such as nitrogen stable isotope ratios (δ15 N values) may record environmental information and ecological role of the fish. However, the isotopic fractionation of δ15 N values between diets and otoliths has rarely been investigated and remains unclear. METHODS Nitrogen isotopic fractionation between five different diets (δ15 Ndiet values) and otoliths (δ15 Noto values) were elucidated in tilapia Oreochromis mossambica reared in controlled feeding experiments. The otoliths were dissolved with hydrogen chloride and peroxodisulfate was used to oxidize the total organic materials to nitrate, which was further converted into N2 O gas by denitrification bacteria before the measurement of δ15 Noto values by isotope ratio mass spectrometry. The δ15 N values of muscles, gills, scales and livers of the tilapias were also measured by isotope ratio mass spectrometry. RESULTS The peroxodisulfate oxidation-bacterial conversion method reduced the minimum mass of the otoliths required for analysis to as low as 2 mg, unlike past methods, which have required masses of 8-155 mg. The δ15 Noto values were not significantly different from the δ15 Ndiet values of the five diets. Furthermore, the somatic growth rate had no effect on the δ15 Noto values. Nevertheless, the δ15 N values of metabolically active tissues were significantly different from each other and higher than the δ15 Ndiet values, due to the deamination of these tissues. CONCLUSIONS These results suggest that diet was the main source of amino acids for the otolith organic matrix and there was no biochemical transamination during the assimilation of dietary amino acids to otoliths. The δ15 Noto value can be used as a proxy of nitrogen sources of fishes and may have potential application in ecological studies such as the detection of diet shift, migration, trophic levels and environmental changes experienced by the fish population.

The Chingshui geothermal field, a moderate-temperature and water-dominated hydrothermal system, was the site of the first geothermal power plant in Taiwan. Many geological, geophysical and geochemical studies using more than 21 drilled wells have been performed since the 1960s. However, there are still controversies regarding the heat and fluid sources due to the tectonically complicated geological setting. To clarify the heat and fluid sources, we analyzed clumped isotopes with carbon and oxygen isotopic compositions of calcite scaling in geothermal wells and veins on outcrops and calculated the δ 18 O values of the source fluids. Two populations of δ 18 O values were calculated: −5.8 ± 0.8‰ VSMOW from scaling in the well and −1.0 ± 1.6‰ to 10.0 ± 1.3‰ VSMOW from outcropping calcite veins, indicative of meteoric and magmatic fluid sources, respectively. Meanwhile, two hydrothermal reservoirs at different depths have been identified by magnetotelluric (MT) imaging with micro-seismicity underneath this area. As a result, we propose a two-reservoir model: the shallow reservoir provides fluids from meteoric water for the scaling sampled from wells, whereas the deep reservoir provides magmatic fluids from deep marble decarbonization recorded in outcropping calcite veins.

Trophic strategy determines stoichiometry of plankton. In general, heterotrophic zooplankton have lower and more stable C:N and C:P ratios than photoautotrophic phytoplankton whereas mixotrophic protists, which consume prey and photosynthesize, have stoichiometry between zooplankton and phytoplankton. As trophic strategies change with cell size, body size may be a key trait influencing eukaryotic plankton stoichiometry. However, the relationship between body size and stoichiometry remains unclear. Here, we measured plankton size-fractionated C:N ratios under different intensities of light and nutrient supply in subtropical freshwater and marine systems. We found a unimodal body size-C:N ratio pattern with a maximum C:N ratio at ~50 µm diameter in marine and freshwater systems. Moreover, the variation in C:N ratios is mainly explained by body size, followed by light intensity and nutrient concentration. To investigate the mechanisms behind this unimodal pattern, we constructed a size-based plankton food web model in which the trophic strategy and C:N ratio is an emergent result. Our model simulations reproduce the unimodal pattern with C:N ratio of photoautotrophs ≤ 50 µm increasing with body size due to increase of photosynthetic carbon, whereas C:N ratios of organisms > 50 µm decreases with size due to decreasing photoautotrophic but increasing heterotrophic uptake. Based on our field observations and simulation, we extend the classic “light-nutrient” theory that determines plankton C:N ratio to include body size and trophic strategy dependency. We conclude that body size and size-dependent uptake of resources (light, nutrients and prey) determine plankton stoichiometry at various light and nutrient supplies.

RATIONALE The stable isotope analysis of carbon and nitrogen is a powerful tool in many ecological studies, but different sample treatments may affect stable isotope ratios and hamper comparisons among studies. The goal of this study was to determine whether treatments that are commonly used to prepare scleractinian coral samples for stable isotope analysis yield different δ15 N and δ13 C values, and to provide guidelines toward a standardised protocol. METHODS The animal tissues and Symbiodiniaceae of two symbiotic scleractinian coral species (Stylophora pistillata and Porites lutea) were divided into subsamples to test the effects of the drying method, lipid extraction, acidification treatment and water washing. All the subsamples were analysed for their δ15 N and δ13 C values, using continuous flow elemental analyser/isotope ratio mass spectrometry. RESULTS The drying method and lipid extraction treatment had no substantial effects on the δ15 N and δ13 C values of Symbiodiniaceae and animal tissues. Acid treatment did cause significant differences in δ13 C values (mean differences ≤0.5‰, with individual samples becoming up to 2.0‰ more negative), whereas no ecologically significant differences were observed in δ15 N values. Animal tissue δ13 C values may vary depending on whether samples are washed or not. CONCLUSIONS To move towards a standardised protocol in coral research, we recommend using an available drying method (as they are equally acceptable) for the stable isotope analysis of scleractinian corals, examining the need for lipid extraction on a case-by-case basis, performing a direct acidification of Symbiodiniaceae and animal tissues, and avoiding washing animal tissue with distilled water.

Radiocarbon has been widely used in determining the age of various geological materials and events. The validity of ages, particularly for sediments, has often been questioned due to the incorporation of carbon-bearing components with different abundances of 13 C and 14 C. This study examines carbon contained in clay minerals (kaolinite, illite and illite-smectite) extracted by temperature-stepped combustion experiments, ranging from 350 °C to 1100 °C. Distinct carbon components were identified in the samples using both their 13 C and 14 C contents. Two carbon end-members were observed for all of the clay minerals: a low temperature component ( 13 C and enriched in 14 C; and a high temperature component (>550 °C), relatively enriched in 13 C and depleted in 14 C. The high temperature carbon component is relatively old and not released until the clay is completely oxidized. This observation suggests that this carbon was incorporated into the clay mineral when it first formed by weathering. We applied the same procedure to sediments collected from terraces along the Kueichung River, in southwestern Taiwan, sieved to

Carbon and nitrogen stable isotope analyses were conducted on Neolithic Yuan-Shan faunal bone collagen to reconstruct a site-specific dietary isotope baseline, and to evaluate the contribution of potential food resources to the diet of Yuan-Shan people. The mean δ 13 C and δ 15 N values of terrestrial mammals were − 17.7 ± 3.6‰ and 5.4 ± 1.3‰, respectively. The mean δ 13 C and δ 15 N values of freshwater fish were − 20.8 ± 2.2‰ and 7.7 ± 2.0‰; while the marine fish had the highest mean δ 13 C (− 11.8 ± 1.2‰) and δ 15 N values (12.1 ± 1.7‰). Combined with archeological evidence and previous isotopic data derived from Yuan-Shan human bone collagen, we suggest that the subsistence strategies of Yuan-Shan people were broad. They relied on rice cultivation, hunting, fishing and gathering food resources from the wild; in addition, they probably raise pigs, as early as 4200 yr BP. Although the Yuan-Shan people relied on broad-spectrum food resources, the foods they mainly consumed were terrestrial herbivores and freshwater fish based on the result of multi-source mixing model. Besides, marine fish, shellfish, and C 3 plants also contributed substantially to their diet. By comparison, the contribution of C 4 plants was minor.

The Tengchong volcanic field, located at the collision zone between the Indian and Eurasian plates, is well known for its large-scale Holocene volcanic eruptions and extensive hydrothermal activities. Bubbling gases from eight geothermal springs at the Tengchong field were collected and analyzed for their chemical and isotopic compositions (3He/4He, 20Ne, N2, Ar, δ13CCH4 and δ13CCO2). The results show that the gas samples could be categorized into a group I dominated by N2 and a group II with CO2 as major component. The air-corrected 3He/4He ratios ranged from 0.17 Ra to 4.76 Ra and the calculated mantle contributions dramatically varied from 1.9% to 77.9% for group II. By contrast, an invariant air-corrected 3He/4He ratio of about 0.30 Ra and a relatively constant mantle contribution of 4.0% to 5.0% was obtained for group I. The sampling sites just on top of the magma chamber received significant mantle-derived helium and magmatic gas components (at the proximal site of the magma chamber: >95% magmatic gas contributions). The calculated N2/Ar ratio of the hydrothermal endmember for group II (sample sites close to the magma chamber) was 61.7–66.2, suggesting that the reaction zone temperature is between 223 °C and 252 °C. The influence of the magma chamber decreases with increasing distance of the sampling sites from the chamber apex. The sampling sites (group I) at the marginal area discharge gases with relatively low 3He/4He ratios and magmatic contributions (19–24%). The temperature of the reaction zone for this group was estimated to be 74 °C based on the N2/Ar ratio of 42. This study provided important constraints to relate hydrothermal gas geochemistry directly with the spatial distribution of the underlying magma chamber. Plain language summary Geochemical characteristics of gases discharged from hydrothermal systems are usually affected by deep magmatic processes, shallow hot fluids circulation, and water-rock interactions in the reaction zone. In this study, we analyzed the gas abundances and isotopic compositions of hydrothermal gas discharged from the Yunnan-Tibet geothermal belt. We used a gas mixing model to quantify the contributions of mantle-derived/magmatic endmember and hydrothermal endmember. The 3He/4He ratios, magmatic contribution, and temperature of the reaction zone decreased significantly with increasing distance from the magma chamber underneath the Tengchong field, highlighting the intimate relationships between gas transport, hydrothermal circulation and the extent of the magma chamber.

Mud volcanoes provide an accessible channel through which deep subsurface environments can be observed. The manner in which deeply sourced materials shape biogeochemical processes and microbial communities in such geological features remains largely unknown. This study characterized redox transitions, biogeochemical fluxes and microbial communities for samples collected from a methane-rich mud volcano in southwestern Taiwan. Our results indicated that oxygen penetration was confined within the upper 4 mm of fluids/muds and counteracted by the oxidation of pyrite, dissolved sulfide, methane and organic matter at various degrees. Beneath the oxic zone, anaerobic sulfur oxidation, sulfate reduction, anaerobic methanotrophy and methanogenesis were compartmentalized into different depths in the pool periphery, forming a metabolic network that efficiently cycles methane and sulfur. Community members affiliated with various Proteobacteria capable of aerobic oxidation of sulfur, methane and methyl compounds were more abundant in the anoxic zone with diminished sulfate and high methane. These findings suggest either the requirement of alternative electron acceptors or a persistent population that once flourished in the oxic zone. Overall, this study demonstrates the distribution pattern for a suite of oxidative and reductive metabolic reactions along a steep redox gradient imposed by deep fluids in a mud volcano ecosystem.

Summary This study evaluated the biogeochemical interactions between arsenic (As) and sulfur (S) in groundwater to understand the natural and anthropogenic influences of S redox processes on As mobilization in the Lanyang Plain, Taiwan. Cl − and the sulfate isotopic composition δ 34 S [ SO 4 ] were selected as conservative tracers. River water and saline seawater were considered as end members in the binary mixing model. Thirty-two groundwater samples were divided into four types of groundwater (I, pyrite-oxidation; II, iron- and sulfate-reducing; III, sulfate-reducing; and IV, anthropogenic and others). The binary mixing model coupled with discriminant analysis was applied to yield a classification with 97% correctness, indicating that the DO/ORP values and δ 34 S [ SO 4 ] and Fe 2+ concentrations are effective redox-sensitive indicators. Type I groundwater is mostly located in a mountainous recharge area where pyrite oxidation is the major geochemical process. A high 18 O enrichment factor e [ SO 4 – H 2 O ] and high 34 S enrichment factor e 34 S [ FeS 2 – SO 4 ] indicate that disproportionation and dissimilatory sulfate reduction are both involved in Type II and Type III groundwater. The process of bacterial sulfate reduction may coprecipitate and sequester As, a mechanism that is unlikely to occur in Type II groundwater. The presence of high As and Fe 2+ concentrations and enriched δ 34 S [ SO 4 ] in Type II groundwater suggest that biogeochemical reactions occurred under anaerobic conditions. The reductive dissolution of As-bearing Fe oxyhydroxides together with microbial disproportionation of sulfur explains the substantial correlations among the high As concentration and enriched δ 34 S [ SO 4 ] and Fe 2+ concentrations in the iron- and sulfate-reducing zone (Type II). The As concentration in Type III groundwater (sulfate-reducing) is lower than that in Type II groundwater because of bacterial sulfate reduction and coprecipitation with As. Furthermore, the dissolution of sulfate minerals is not the major source of aqueous SO 4 , based on the sulfur isotopic composition of solid-phase sulfate (δ 34 S [sulfate mineral] ). Finally, the anthropogenic influence of fertilizers with wide S isotopic ranges is proposed as the plausible sulfate budget in Type IV groundwater. The results of this study suggest that the As release into groundwater involves the reductive dissolution of As-bearing Fe-hydroxides, bacterial sulfate reduction, and microbial disproportionation in the Lanyang Plain.

The Chingshui geothermal field once hosted the first geothermal power plant in Taiwan from 1981 to 1993. After a long period of inactivity, this field is attracting renewed interest to meet the need for clean energy. A 213-m length of cores (IC-21) with continuous recovery, the longest in the Chingshui geothermal field, was recovered from 600 m to 813 m below the surface in 2010. Three types of calcite crystal morphologies have been identified in the veins of the cores of well IC-21: bladed, rhombic and massive crystals. Bladed calcites are generated via degassing under boiling conditions with a precipitation temperature of ∼165 °C and calculated δ 18 O value of −6.8‰ to −10.2‰ VSMOW for the thermal water. Rhombic calcites grow in low concentration Ca 2+ and CO 3 2− meteoric fluids and precipitate at approximately ∼180 °C. Finally, massive calcites are characterized by co-precipitation with quartz in the mixing zone between meteoric water and magmatic or metamorphic fluids with calculated δ 18 O value of up to 1.5 ± 0.7‰ VSMOW. Furthermore, the scaling and hot fluids at a nearby pilot geothermal power plant confirm a meteoric origin. Based on these observations, we propose that the current orientations of the main conduits for geothermal fluids are oriented at N10°E with a dip of 70°E. This result provides the basic information needed for deploying production and injection wells in future developments of the geothermal power plant in this region.

We propose an improved method for precise sulfur isotopic measurements by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) in conjunction with a membrane desolvation nebulization system. The problems of sulfur loss through the membrane desolvation apparatus are carefully quantified and resolved. The method overcomes low intrinsic sulfur transmission through the instrument, which was initially 1% when operating at a desolvation temperature of 160 °C. Sulfur loss through the membrane desolvation apparatus was resolved by doping with sodium. A Na/S ratio of 2 mol mol −1 produced sulfur transmissions with 98% recovery. Samples of 3 nmol (100 ng) sulfur achieved an external precision of ±0.18‰ (2 SD) for δ 34 S and ±0.10‰ (2 SD) for Δ 33 S (uppercase delta expresses the extent of mass-independent isotopic fractionation). Measurements made on certified reference materials and in-house standards demonstrate analytical accuracy and reproducibility. We applied the method to examine microbial-induced sulfur transformation in marine sediment pore waters from the sulfate-methane transition zone. The technique is quite versatile, and can be applied to a range of materials, including natural waters and minerals.

Temperamental tendencies may form the basis of personality development, and specific personality constellations are associated with increased incidences of behavioural problems. Phthalic acid ester (PAE) has been associated with symptoms of attention deficit hyperactivity disorder (ADHD) in cross-sectional studies. We hypothesised that early-life exposure to PAE affects the temperaments of children, particularly ADHD traits. In this study, we analysed the temperament evaluations completed at least once by maternal–infant pairs (n = 208) when the child was aged 2, 5, and/or 11 years between 2000 and 2012. We measured seven PAE metabolites in the urine of the mothers during pregnancy and their children using liquid chromatography-electrospray ionisation-tandem mass spectrometry. These metabolites included mono-methyl phthalate, mono-ethyl phthalate, mono-butyl phthalate (MBP), mono-benzyl phthalate (MBzP), and three metabolites of di (2-ethylhexyl) phthalate. The phthalate metabolite levels in pregnant women were significantly associated with a decreased threshold of responsiveness (coefficients from −0.21 to −0.46) and increased distractibility (coefficients from 0.23 to 0.46) in pre-school children. After adjustment for maternal exposure, the phthalate metabolite concentrations of the children exhibited significantly increased odds ratios (ORs) with respect to the ADHD symptom traits. Specifically, mono-2-ethyl-5-hydroxyhexyl phthalate (MEHHP), the sum of the DEHP metabolites, and MBzP yielded ORs and 95% confidence intervals of 2.98 (1.05–8.48), 3.28 (1.15–9.35), and 9.12 (1.07–78.06), respectively, for every log10 creatinine unit (g/g creatinine) increase. Thus, early-life phthalate exposure was found to be associated with the behavioural characteristics of children, particularly temperamental traits associated with ADHD.

High-strength ZrC ceramics with relative density above 98% were prepared by reactive hot pressing of ZrC and Al at 1900°C. The reaction between ZrC and Al resulted in the formation of ZrC1−x, Zr3Al3C5 and Zr–Al compound such as AlZr3 and Al–C–Zr. The intermediate product AlZr3 below 1600°C and remained Al–C–Zr phase could form liquid phase and promoted the first stage of densification process. The improvement in densification behavior at higher temperatures (1800°C–1900°C) could be attributed to the formation of nonstoichiometric ZrC1−x. Adding 5 wt% and 7.5 wt% Al to ZrC, the formed ZrC0.85–Zr3Al3C5 and ZrC0.80–Zr3Al3C5 based ceramics had 3-point bending strength as high as 757 ± 79 MPa and 967 ± 50 MPa, respectively, with hardness and fracture toughness being 16.2–18.3 GPa and 3.3–3.5 MPa m1/2, respectively.

Terrestrial hydrocarbon seeps are an important source of naturally emitted methane over geological time. The exact community compositions responsible for carbon cycling beneath these surface features remain obscure. As sulfate reduction represents an essential process for anoxic organic mineralization, this study collected muddy fluids from a high-temperature hydrocarbon seep in Taiwan and analyzed community structures of sulfate-supplemented sediment slurries incubated anoxically at elevated temperatures. The results obtained demonstrated that sulfate consumption occurred between 40°C and 80°C. Dominant potential sulfate reducers included Desulfovibrio spp., Desulfonatronum spp., Desulforhabdus spp., and Desulfotomaculum spp. at 40°C, Thermodesulfovibrio spp. at 50°C, Thermodesulfovibrio spp. and Thermacetogenium spp. at 60°C, Thermacetogenium spp. and Archaeoglobus spp. at 70°C, and Archaeoglobus spp. at 80°C. None of these potential sulfate reducers exceeded 7% of the community in the untreated sample. Since no exogenous electron donor was provided during incubation, these sulfate reducers appeared to rely on the degradation of organic matter inherited from porewater and sediments. Aqueous chemistry indicated that fluids discharged in the region represented a mixture of saline formation water and low-salinity surface water; therefore, these lines of evidence suggest that deeply-sourced, thermophilic and surface-input, mesophilic sulfate-reducing populations entrapped along the subsurface fluid transport could respond rapidly once the ambient temperature is adjusted to a range close to their individual optima.

summary This study explores the distribution and mobilization of As in the ecosystem of the Guandu wetlands, Taiwan. The chemical parameters, chemical sequential extraction, mineralogical compositions, and sulfur isotopic compositions (i.e., d 34 S½SO4� and d 18 S½SO4� ) of porewater and two sediment core samples (S2 and S5, locate in the inner and outer sites of the Guandu wetland) were analyzed to characterize As spatial distribution. The crucial mechanisms of the biogeochemical processes that control As mobility in wetland ecosystems were inferred. Based on factor analysis and cluster analysis, the vertical distributions of the redox zones in S2 and S5 were classified as oxidizing, transitional, and reducing zones, respectively. The mineralogical characteristics showed that adsorption and desorption are the major processes which control As retention in the surface sediment under cyclic aerobic/anaerobic conditions. Aqueous As and Fe were restrained because of oxidation, whereas aqueous Fe precipitated as amorphous metal oxides (i.e., FeO, FeOOH, and Fe2O3). Subsequently, aqueous As was adsorbed onto the surfaces of Fe(hydr)oxides, resulting in a high solid As content in the oxidizing zone. The high aqueous As content in the boundary of the transitional and reducing zones was caused by the reductive dissolution of highly dissolved Fe compounds through the microbial respiration of organic matter (OM). In the reducing zone, As 3+ can be constrained by the formation of FeS2 in sediment during bacterial sulfate reduction that is governed by the relative enrichment of the d 34 S½SO4� and d 18 S½SO4� values. Sulfur disproportionation and the redox of ele

Source at https://doi.org/10.1002/2017GC006798 To systematically quantify the production, consumption, and migration of methane, 210 sediment cores were collected from offshore southwestern Taiwan and analyzed for their gas and aqueous geochemistry. These data, combined with published results, were used to calculate the diffusive methane fluxes across different geochemical transitions and to develop scenarios of mass balance and constrain deep microbial and thermogenic methane production rates within the accretionary prism. The results showed that methane diffusive fluxes ranged from 2.71 × 10−3 to 2.78 × 10−1 and from –1.88 × 10−1 to 3.97 mmol m−2 d−1 at the sulfate‐methane‐transition‐zone (SMTZ) and sediment‐seawater interfaces, respectively. High methane fluxes tend to be associated with structural features, suggesting a strong structural control on the methane transport. A significant portion of ascending methane (>50%) is consumed by anaerobic oxidation of methane at the SMTZ at most sites, indicating effective biological filtration. Gas compositions and isotopes revealed a transition from the predominance of microbial methane in the passive margin to thermogenic methane at the upper slope of the active margin and onshore mud volcanoes. Methane production and consumption at shallow depths were nearly offset with a small fraction of residual methane discharged into seawater. The flux imbalance arose primarily due to the larger production of methane through deep microbial and thermogenic processes at a magnitude of 1512–43,096 Tg Myr−1 and could be likely accounted for by the sequestration of methane into hydrate forms, and clay absorption.

Hydrocarbon seepage is a surface expression where fluids mixed with sediments and hydrocarbons are expelled through fracture systems that potentially tap into gas–petroleum reservoirs. Hydrocarbons released from most seeps appear to be thermogenic on the basis of their relative abundance and isotopic composition. The potential for subsurface microbial processes modifying these geochemical fingerprints remains poorly constrained. In this study, microcosm incubations were conducted on mud slurries supplied with/without various methanogenic precursors at temperatures ranging from ambient conditions to 90 °C, in order to assess microbial CH4 formation in the subsurface beneath hydrocarbon seeps. The analyses indicated that CH4 production was positive at ⩽80 °C, regardless of whether or not or which precursors were added. However, the pattern of CH4 production rates varied with the precursor and temperature. In general, the optimum CH4 production from H2/CO2 and formate occurred over a wide range of temperatures (⩾40 °C), whereas that from acetate, methanol and methylamine was restricted to relatively lower temperatures (40–50 °C). The CH4 recoveries, together with the C isotopic compositions of CH4, further indicated that the quantities of CH4 produced could not completely account for the quantities of precursor consumed, suggesting that a complex metabolic network was involved in the transformation of the added precursor and organic C inherited from inoculated sediments. Microbial CH4 was estimated to constitute 7–61% of the CH4 observed using experimentally-derived apparent isotope fractionations as the end member compositions. This illustrates the possibility that microbial CH4 produced at shallower depths could quantitatively and isotopically alter deeply-sourced thermogenic CH4 in hydrocarbon seep environments.

Terrestrial mud volcanism represents the prominent surface geological feature, where fluids and hydrocarbons are discharged along deeply rooted structures in tectonically active regimes. Terrestrial mud volcanoes (MVs) directly emit the major gas phase, methane, into the atmosphere, making them important sources of greenhouse gases over geological time. Quantification of methane emission would require detailed insights into the capacity and efficiency of microbial metabolisms either consuming or producing methane in the subsurface, and establishment of the linkage between these methane-related metabolisms and other microbial or abiotic processes. Here we conducted geochemical, microbiological and genetic analyses of sediments, gases, and pore and surface fluids to characterize fluid processes, community assemblages, functions and activities in a methane-emitting MV of southwestern Taiwan. Multiple lines of evidence suggest that aerobic/anaerobic methane oxidation, sulfate reduction and methanogenesis are active and compartmentalized into discrete, stratified niches, resembling those in marine settings. Surface evaporation and oxidation of sulfide minerals are required to account for the enhanced levels of sulfate that fuels subsurface sulfate reduction and anaerobic methanotrophy. Methane flux generated by in situ methanogenesis appears to alter the isotopic compositions and abundances of thermogenic methane migrating from deep sources, and to exceed the capacity of microbial consumption. This metabolic stratification is sustained by chemical disequilibria induced by the mixing between upward, anoxic, methane-rich fluids and downward, oxic, sulfate-rich fluids.

WC powder was synthesized by a nitridation–carburization method with WO3 prepared by the citrate sol–gel route as the starting material, and the reaction mechanism was investigated. It was found that WO3 was converted to nanosized W2N after the nitridation process in NH3. Then, the W2N was transformed to W metal, W2C, and WC in sequence when it was carburized in CH4–H2 gas mixture. The WC powder obtained possessed a high specific surface area of 24.6 m2/g, and showed a particle size of 20–30 nm, which was much finer than the WC powder prepared by direct carburization of WO3 in CH4–H2 gas mixture. The reason was also discussed.

The influence of the spark plasma sintering (SPS) heating rate on densification, microstructure and strength of ZrB2–20 vol.% SiC composites with or without 5 vol.% Yb2O3 addition was assessed. A low heating rate promoted densification, induced grain growth and slightly increased the strength in the Yb2O3-free ceramics, whereas the low heating rate inhibited the densification, maintained the grain size and greatly decreased the strength in the Yb2O3-doped composites.

Using three elementary substances, Mo, Ni, and amorphous B powders as raw materials, the ternary boride based hard alloy Mo2NiB2–Ni was prepared successfully. The formation mechanism of the ternary phase was verified by XRD. It was indicated that the formed Mo2NiB2 particles at lower temperatures could be as seeds for the further formation of Mo2NiB2 directly from the raw materials of Mo, Ni and B at higher temperatures. The appearance of liquid phases between 1100 and 1200 °C was important for the densification of hard alloy. The microstructures of the hard alloys were observed by SEM. The main fracture modes for the hard alloys were different for the samples sintered at different temperatures. The maximum bending strength and the Rockwell hardness reached 1.85 ± 0.04 GPa and 85.7 ± 0.1 HRA, respectively. These values were comparable to those reported in literature.

The ball-milling process is a usual route employed to break up agglomerates in the powder or mix the powder with additives when preparing ceramics. Although it is well known that a powder can be “contaminated” by the wear particles from the milling balls, the study dealing with how the preparation and properties of a hard material would be affected by additives just introduced by scrape of milling balls has been scarce. In the present work, sintering behavior and mechanical properties of hot-pressed B 4 C with additives derived from milling balls were investigated. Polyoxymethylene, ZrO 2 , Al 2 O 3 and Si 3 N 4 were selected as different ball materials. The results show that the sinterability of B 4 C could be significantly enhanced because of the incorporation of one of these additives, i.e. ZrO 2 , Al 2 O 3 and Si 3 N 4 (approximately 3–6 vol%). As a result of improvement in density, excellent mechanical properties of B 4 C ceramics were obtained. Among them a flexural strength of B 4 C added by ZrO 2 reached 630 MPa.

Alterable roles of VC addition on the densification, microstructure development, and mechanical properties of the ZrB2–SiC ultrahigh temperature ceramics (UHTCs) were comprehensively investigated based on utilizing the thermodynamic analysis and experimental results. Chemical reactions of VC with the inevitably existed oxide (ZrO2) impurity on the particle surfaces of the ZrB2 starting powder, or with the ZrB2 matrix phase could be controlled by adjusting the atmospheres during hot pressing. Different chemical reactions during hot pressing also resulted in much different material microstructures and then different material properties. Benefiting the VC addition and proper sintering atmosphere, refined grain size of ZrB2 and improved mechanical properties were developed in ZrB2–SiC systems. By properly controlling these reactions, the microstructures and mechanical properties of ZrB2–SiC based UHTCs could be tailored.

ZrB 2 –20 vol% SiC composites with 3 vol% Re 2 O 3 rare-earth oxide (Re = La, Nd, Y or Yb) were hot pressed to near full-density at 1900 °C. The La 2 O 3 and Nd 2 O 3 additions not only caused the formation of an amorphous grain boundary phase and enhanced densification, but also resulted in substantial ZrB 2 and SiC grain growth. In contrast, the Y 2 O 3 and Yb 2 O 3 additions resulted in the formation of crystalline (Y/Yb) 2 Zr 2 O 7 and enhanced densification without ZrB 2 and SiC grain growth. The hardness was improved by the rare-earth oxide addition, especially with Y 2 O 3 and Yb 2 O 3 . The La 2 O 3 and Nd 2 O 3 only had a minor effect on the fracture toughness, whereas the Y 2 O 3 and Yb 2 O 3 additions increased the fracture toughness. The type of Re 2 O 3 addition was found to influence the nature of the grain boundary and the concomitant fracture and toughening mechanisms.

Using Si and BN powders as raw materials, silicon nitride/hexagonal boron nitride (Si 3 N 4 /BN) ceramic composites were fabricated at a relatively low temperature of 1450 °C by using the reaction bonding technology. The density and the nitridation rate, as well as the dimensional changes of the specimens before and after nitridation were discussed based on weight and dimension measurements. Phase analysis by X-ray diffraction (XRD) indicated that BN could promote the nitridation process of silicon powder. Morphologies of the fracture surfaces observed by scanning electron microscopy (SEM) revealed the fracture mode for Si 3 N 4 /BN ceramic composites to be intergranular. The flexural strength and Young's modulus decreased with the increasing BN content. The reaction-bonded Si 3 N 4 /BN ceramic composites showed better machinability compared with RBSN ceramics without BN addition.

Phase pure hafnium diboride (HfB 2 ) powder was synthesized by borothermal reduction of hafnium dioxide using amorphous boron at relatively low temperature (1600°C) in vacuum. The synthesized HfB 2 powder had an average particle size of 1.37 μm with an equiaxed shape, and a low oxygen content of 0.79 wt%. Using the as-synthesized HfB 2 powder and a commercial SiC, HfB 2 monolithic, and HfB 2 -20 vol%SiC composite were hot pressed at 2000°C to relative densities of 95.7% and 99.2%, respectively. With the addition of SiC, the grain size decreased and the fracture behavior changed from intergranular to a mixed mode, which resulted in a high flexural strength of 993 ± 90 MPa for the composite. Fracture toughness of the composite was 6.29 ± 0.65 MPa m 1/2 , which was significantly higher than that of the HfB 2 monolithic and the reported values in literature.

Three ZrB2–SiC composites were prepared from polycarbosilane (PCS)-coated ZrB2 powders. Powders with or without additions of Si or Zr were densified by hot pressing at 1800 °C. Finally, the oxidation resistance of the composites was studied at 1500 °C in air. The phase composition and microstructure were characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM) along with energy-dispersive spectroscopy (EDS). Results showed that Si addition, which reacted with free carbon coming from the pyrolyzed PCS to produce the SiC, improved the oxidation resistance of ZrB2–SiC composites with PCS as a precursor, whereas Zr addition, which reacted with the carbon to produce the ZrC, decreased it.

Fine hafnium diboride (HfB2) powders have been prepared by modified carbothermal/borothermal reduction of hafnium dioxide (HfO2) at relatively low temperatures (1500°–1600°C) for 1–2 h. The XRD patterns could be indexed as hexagonal HfB2 and no evidence of HfC, HfO2, or other impurities was observed. Glow discharge mass spectrometer analysis indicates that the synthesized HfB2 powders had high purity. The synthesized HfB2 powders had small average crystallite size (around 1 μm) and low oxygen content (

Adding a small amount of vanadium carbide as sintering aids, nearly fully dense ZrB2–SiC composites were obtained by pressureless sintering methods at 2000–2100 °C. Thermodynamic calculations and experimental results proved that VC is better at removing the surface oxide impurities of ZrB2 than WC, and played a very important role during the densification process. The mechanical properties of the sintered ceramics were also reported.

ZrB 2 –20 vol%SiC ceramics without and with additive of 2 wt% carbon nanotubes (CNTs) were fabricated by hot-pressing at 1900 °C for 1 h under 30 MPa using ZrB 2 , SiC and CNTs as starting materials. The fracture toughness increased about 15%, but hardness, flexural strength as well as thermal conductivity did not vary significantly from the addition of CNTs.

The isothermal oxidation behavior of Cr2AlC ceramics oxidized in air at 1,100 and 1,250 °C for 20 h was studied. The phase compositions and microstructure of the oxidized surface were identified and observed by XRD and electron probe microanalysis (EMPA), respectively, while the cross sections of oxidized samples were also examined by EMPA equipped with energy dispersive spectrum capabilities. The results indicated that the oxidation of Cr2AlC samples was carried out by the outward diffusion of Al, together with small amounts of Cr, and the inward diffusion of O to form a surface layer of α-Al2O3, while carbides (Cr7C3 and Cr3C2), rather than oxides (Cr2O3), were formed in a layer under the surface. The mass gain per unit surface area of oxidized Cr2AlC followed a parabolic relation with oxidation time, and the parabolic rates, kp, for oxidation at 1,100 and 1,250 °C were 1.1 × 10−12 and 7.1 × 10−10 kg2 m4 s−1, respectively.

Neodymium-modified bismuth titanate (BNT) powder with compositions of Bi 4− x Nd x Ti 3 O 12 ( x = 0, 0.2, 0.5 and 0.75) were prepared through a hydrolysis method. The influence of Nd addition on the powder characteristics, sintering, microstructure and properties were investigated. It was found that the absorption band of Ti–O stretching vibration at 589 cm −1 was shifted to a higher wave number in the IR spectra, and the sintering as well as grain growth was significantly retarded. The Curie temperature, dielectric loss and Curie peak intensity were steadily decreased with an increase in Nd concentration, and the dielectric constant and loss tangent became much less dependent on temperature and frequency. At the same time, the polarization properties of the material were greatly improved.

Powders of Nd/V-doped Bi4Ti3O12 with a composition Bi3.74Nd0.26Ti2.98V0.02O12.01 (BNTV), prepared by the molten salt synthesis, using chlorides as the fluxes, were successfully obtained. The influences of the molar ratio of KCl to NaCl, temperature, and soak time on the formation and morphology of BNTV were investigated. The results indicated that Na+ can enter the lattice of Bi4Ti3O12 (BIT), leading to a decrease in the cell dimensions of BIT phase. The grain size and morphology of BNTV powders were considerably affected by the molar ratio of KCl to NaCl in the fluxes, in which the platelets showed the morphology of a rectangle and no regular shape in KCl and NaCl fluxes, respectively. The grain size of BNTV increased with increasing amount of NaCl in the fluxes, but the thickness decreased. The platelets prepared in the NaCl flux were faceted along (0 0 1) plane.

Four kinds of composites, ZrB2–SiC, ZrB2–SiC–ZrC, ZrB2–SiC–ZrN and ZrB2–SiC–AlN, were synthesized in situ via reactive hot pressing (RHP) and reactive spark plasma sintering (R-SPS), using Zr, Si, B4C, BN and Al as raw materials. The synthesis process plays a critical role in the microstructural features of the composites obtained. The R-SPS process can lead to a more homogeneous and finer microstructure due to its high heating rates and short holding time, while the RHP process is likely to result in coarse microstructures due to a long enough holding time for grains growth.

Dense and predominantly single-phase samples of Cr2AlC, together with a trace amount of Cr7C3, were fabricated by hot pressing of a mixture of chromium, aluminum, and graphite powders at 1400°C for 1 h. The hardness, Young's modulus, flexural strength, and compressive strength of Cr2AlC samples were 5.2, 288 GPa, 483±29, and 1159±23 MPa, respectively, which are comparable with those of Ti3AlC2 and Nb2AlC. The material exhibits good damage tolerance. For indentation loads up to 50 N, the post-indentation flexural strengths decrease by approximately 10% and by 31% for a load of 100 N. The flexural strengths of Cr2AlC samples quenched from 300°C to room temperature decrease from 483 to 455 MPa, while the retained strengths decrease quickly to 199 MPa when the quench temperature increases to 500°C. A further increase in quench temperature to 700°, 900°, and 1100°C results in a small reduction of strength.

ZrB 2 –SiC–C ultra high temperature ceramics (UHTCs) have been produced by hot pressing pyrolyzed mixtures of ZrB 2 and polycarbosilane (PCS). Samples with SiC contents of 0%, 5% and 16% in volume derived from PCS were prepared. The phase composition, microstructure and mechanical properties were characterized for composites hot pressed at 2073 K for 60 min under the pressure of 20 MPa in an argon atmosphere. Analysis showed that the addition of PCS improved the relative density from 78% (without PCS addition) to ∼ 100% (with 16% SiC derived from PCS addition). Hardness and fracture toughness of the composite were also improved.

A stabiliser coating technique was applied to prepare mixed Nd2O3 +Y 2O3 coated ZrO2 nanopowder from an alcohol/water based suspension of neodymium nitrate, yttrium nitrate and monoclinic zirconia nanopowder. The mixed stabiliser starting powders could be fully densified into (Nd,Y)TZP ceramics by pressureless sintering in air at 1450 ◦ C. The obtained ceramics revealed an excellent fracture toughness up to 12.8 MPa m 1/2 in combination with a hardness of 11 GPa, a toughness that is comparable to that of the traditional 12 mol CeO2-stabilised TZP but with higher hardness.

Thermodynamic assessment in the ternary systems ZrO2-CeO2-Y2O2 , ZrO2-CeO2-Ce2O3 and the limiting binaries ZrO2-Y2O3, ZrO2-CeO2 ,CeO2-Y2O2, ZrO2-Ce2O3, CeO2-Ce2O3 as well as the modeling for oxides are reviewed comprehensively. Based on the recent estimations on the YO1,5-CeO2, ZrO2-CeO2 and ZrO2-YO1,5 systems, isothermal sections at 1 273 and 1 973 K of the ternary CeO2-ZrO2-YO1,5 system are calculated. In the system of ZrO2-CeO2-Ce2O3, the complex relation between the nonstoichiometry (y) in CeO−y , the composition of the ZrO2-CeO2 solid solution and the oxygen partial pressure (P o 2) for different ZrO2 containing solid solutions Ce2Zri2−y are evaluated from 1 473 to 1 773 K. The relation between the degree of Ce+4 reduction to Ce+3 under different P 0 2 in the fluorite CeO2−y and Ce z Zr1−z O2−x solid solutions at different temperatures can be used as a guide in the development of functional ceramics.

The phase assembly of 1.0–5.0 mol% Nd 2 O 3 -doped ZrO 2 sintered at 1400 °C revealed that the tetragonal ZrO 2 phase could not be completely stabilised. Co-stabilising of 0.5–2.5 mol% Nd 2 O 3 with 0.5–1.0 mol% Y 2 O 3 , however, allowed the preparation of fully dense (Nd,Y)-TZP ceramics by pressureless sintering in air at 1450 °C. The mixed stabiliser monoclinic zirconia nanopowder starting material was synthesized from a suspension of neodymium nitrate, yttrium nitrate and monoclinic zirconia powder in an alcohol/water mixture. A HV 30 hardness of 10 GPa combined with an excellent indentation toughness of 13 MPa m 1/2 could be achieved for the (1.0Nd,1.0Y)- and (1.5Nd,1.0Y)-TZP ceramics. The influence of the mixed stabiliser content on the phase stability and mechanical properties are investigated and discussed.

The contributions of scattering effects to the X-ray fluorescent intensities were calculated by considering the intensity of scattered primary fluorescence radiation that is scattered into the direction of detector, the secondary enhancement by coherent scattering radiation and incoherent scattering radiation for light matrix samples on the basis of the theoretical calculations. Relative intensities for nine different characteristic X-ray lines for the synthesized fused disks were calculated and compared with the measured relative intensities. It was found from this study that the contributions of scattering effects to the fluorescent intensities of analytes in fused disk samples are sizeable. Moreover, the magnitude of contribution of scattering effects increases with the increase of atomic number of analyte or/and the decrease of the content of the fluorescent element in the fused disk samples, which is about several percents of that excited by primary radiation, or even more than 10% for PbLβ1. The average relative error of the calculated relative intensities compared with the measured values is 0.93% after scattering effects was considered, while the average relative error of the values calculated by NRLXRF for the same lines is 2.75%. The calculated relative intensities after considering the scattering effects are more agreeable to the measured values. Therefore, more accurate results for fundamental parameter method are expected with the consideration of scattering effects, especially for light matrix samples.

A novel stabilizer coating technique was applied to prepare 1.0 mol% Nd2O3+1.0 mol% Y2O3-co-coated ZrO2 nanopowder from an alcohol/water-based suspension of neodymium nitrate, yttrium nitrate and monoclinic zirconia powder. The low stabilizer content starting powder could be fully densified into a (1Nd,1Y)-TZP ceramic when pressureless sintering in air at 1450 8C. The obtained ceramic revealed an excellent fracture toughness of 12.5 MPa m 1/2 in combination with a hardness of 10 GPa, a combination of properties that is comparable with that of the traditional 12 mol CeO2-stabilised tetragonal zirconia polycrystalline (TZP). The toughness could be further increased up to 14.3 MPad m 1/2 by the addition of 2 wt.% Al2O3 to the starting powder.

Oxygen isotopic compositions of silicate inclusions in IVA iron meteorites have been measured with an in situ UV laser microprobe technique. The homogeneity of oxygen isotopic compositions within and among individual mineral grains has also been examined. Oxygen isotope fractionations between coexisting mineral pairs were utilized in oxygen isotope thermometry. Our measured Δ17O values, ranging from 0.97 to 1.25‰, are characteristic of a single reservoir and fully confirm the oxygen isotopic similarity between IVA irons and L/LL chondrites. Steinbach and Sao Joao Nepomuceno, containing inclusions of two silicate minerals in mutual contact, exhibit a mass-dependent fractionation of 18O/16O between tridymite and bronzite with apparent oxygen isotopic heterogeneity. The SiO2-bearing member, Gibeon, gives homogeneous oxygen isotopic compositions without detectable fractionation of 18O/16O between tridymite and quartz. Oxygen isotope equilibrium temperatures are estimated for coexisting tridymite and bronzite in the same sample slabs or clusters in Steinbach and Sao Joao Nepomuceno. The fractionations of 18O/16O between bronzite and tridymite range from 1.6 to 2.3‰ in different sample slabs or clusters. On the basis of the closure temperature concept, cooling rates are estimated at approximately 20 to 1000°C/Myr between 800 and 1000°C, a range of temperatures not accessible to other cooling rate methods. Using the Fast Grain Boundary diffusion model, we have demonstrated that significant oxygen heterogeneity both in tridymite and bronzite is probably due to isotope exchange during cooling between minerals with various grain sizes and mineral abundances in different regions of the samples. The new estimates of cooling rate by oxygen isotope thermometry refine previous cooling curves of IVA irons and support the breakup-reassembly model for the IVA parent body.

(Ca,Mg)-α-sialon powders were previously [J. Mater. Chem. 12 (2002) 1199] prepared by Self-propagating high-temperature synthesis (SHS) technology using slag as a raw material (abbreviated as Slag α-sialon powder). In this study, phase assemblages of the Slag α-sialon samples hot-pressed from 1450 to 1700 °C were investigated. Results indicated that α-sialon was the main crystalline phase in the whole sintering process, however, a small amount of β-sialon appeared in the samples sintered at 1500 °C and above. In addition, the SHS technique was also used to prepare α-sialon powders using chemical agents as raw materials (named Chem α-sialon). Samples made from the Chem α-sialon powder were hot-pressed under the same conditions for a comparison. Similar phase assemblages were obtained for the samples starting from Chem α-sialon powders, except for even more amount of βsialon phase contained. Material with a single α-sialon phase could be got in both samples when 10 wt.% additional slag and CaCO 3 were introduced into the Slag α-sialon and Chem α-sialon starting powders respectively.

Textured bismuth titanate (Bi 4 Ti 3 O 12 ) ceramics were fabricated by templated grain growth (TGG), using plate-like Bi 4 Ti 3 O 12 particles prepared by a molten salt method as the templates. The templates were aligned in the fine-grained matrix by aqueous tape casting with their major surface parallel to the casting plane. Effect of sintering conditions on the grain orientation in the material was investigated. It was found that the degree of grain orientation (Lotgering factor, f ) increased with the increase in sintering temperature, soaking time and heating rate. High Lotgering factor ( f ⩾0.92) can be obtained through careful control of the sintering parameters. The textured Bi 4 Ti 3 O 12 ceramics showed a high anisotropy in its dielectric properties in the directions parallel and perpendicular to the casting plane.

A laser fluorination microprobe system has been constructed for high-accuracy, high-precision multisulfur isotope analysis with improved spatial resolution. The system uses two lasers: (a) a KrF excimer laser for in situ spot analysis by ultraviolet (UV) photoablation with λ = 248 nm and (b) a CO2 laser for whole-grain analysis of powdered samples by infrared heating at λ = 10.6 μm. A CO2 laser is necessary for the analysis of interlaboratory isotope reference materials because they are supplied as powders. The δ34S and δ33S compositions of reference materials measured with a CO2 laser fluorination system agree (±0.2‰, 1σ) with the recommended values by the Sulfur Isotope Working Group of the International Atomic Energy Agency Ding et al 2001 , Taylor . The precision of replicate analyses of powdered sulfide minerals with the CO2 laser is typically ±0.2‰ (1σ) for δ34S. The in situ fluorination of sulfides with a KrF excimer laser (λ = 248 nm) was validated by comparison of measurements of side-by-side laser craters and powders excavated from drill holes. Powders from drill holes were analyzed with the CO2 laser. In situ laser craters and drill hole powders give the same δ34SV-CDT and δ33SV-CDT values within 0.2‰. The δ34SV-CDT and δ33SV-CDT values of both powders and in situ analyses are independent of F2 gas pressure over a range of 15 to 65 torr. No dependence of δ34SV-CDT and δ33SV-CDT values on UV laser energy fluence has been observed. Mineral-specific fractionation of sulfur isotopes in analyzing pyrite, sphalerite, galena, troilite, and chalcopyrite has not been observed with a KrF excimer laser (λ = 248 nm). Test analyses with an ArF excimer laser (λ = 193 nm), however, gave fractionated sulfur isotope ratios. A range of Δ33S anomalies of from – 1.5 to +3.0‰ in Archean samples from the North Pole district, Pilbara Craton, Australia, and from black shale of the Lokamonna Formation, South Africa, were verified by in situ analysis of individual pyrite grains with a KrF excimer laser. These results show that a combination of high-accuracy, high-precision analyses with improved spatial resolution permits locating and analyzing host minerals of non-mass-dependent sulfur isotope anomalies.

Bismuth titanate (Bi 4 Ti 3 O 12 ) platelets were obtained by the molten salt synthesis method in NaCl–KCl and Na 2 SO 4 –K 2 SO 4 fluxes, using an amorphous Bi 4 Ti 3 O 12 precursor and a mechanically mixed Bi 2 O 3 –TiO 2 mixture as the starting materials. It was found that the synthesizing temperature, salt species and starting materials could significantly affect the crystallization habit and morphology of Bi 4 Ti 3 O 12 platelets. Under the same processing conditions (i.e. in Na 2 SO 4 –K 2 SO 4 flux at 1000 °C), the Bi 4 Ti 3 O 12 platelets synthesized from the Bi 2 O 3 –TiO 2 mixture generally showed a smaller particle size than those synthesized using the amorphous Bi 4 Ti 3 O 12 precursor. The Bi 4 Ti 3 O 12 platelets prepared in the chloride flux were faceted along either (0 0 1) or (1 1 2) planes, while those prepared in the sulfate flux were solely (0 0 1) faceted. The former system also had smaller particle size than the latter. Furthermore, the salt content and the addition of plate-like Bi 4 Ti 3 O 12 seeds in the amorphous Bi 4 Ti 3 O 12 precursor showed a strong influence on the particle size of the synthesized Bi 4 Ti 3 O 12 platelets. The particle size of Bi 4 Ti 3 O 12 platelets prepared in the sulfate flux decreased as the mole ratio of the sulfate salts to Bi 4 Ti 3 O 12 was increased from 7.9 to 23.7. And the addition of 10 wt.% plate-like Bi 4 Ti 3 O 12 seeds into the amorphous Bi 4 Ti 3 O 12 precursor led to a significant increase in the particle size of the resulting Bi 4 Ti 3 O 12 platelets.