Charcoal remains and bulk lignites collected from the late Pliocene Jinsuo Basin in Yunnan, southwestern China, have been studied to reveal changes in the wildfire regime related to changes of the palaeoenvironment, palaeoclimate, and paleobotany. Different types of wildfire occurred in this paleomire with a predominance of low-temperature surface fires, as indicated by mean inertinite reflectance (Ro) values ranging from 1% to 2% in most samples. High-temperature fires are less recorded and occurred more frequently in dark layers compared with pale layers and charcoal layers, as deduced from the elevated proportion of high Ro values ( 3%) produced by crown fires or high-temperature surface fires. Wildfire distribution in pale and dark layers was probably influenced by, changes of both plant community and of the depositional environment during their formation. Charcoal layers represent in situ surface and ground fires, whereas pale and dark layers probably record both in situ and remote fire events inside and/or around the basin. PAH were detected in all samples throughout the whole lignite seam, indicating that burning temperatures were low (< 400 degrees C) in most cases in the peatland. Evidence of pre-charring decay observed in some macro-charcoal fragments and pyrogenic inertinite, along with the relatively high content of perylene, shows that decaying wood materials could be a part of the source fuel for the combustion during ground or surface fires. The occurrence and spread of wildfires in the basin during the formation of pale layers probably owe to the drought conditions driven by climate, whereas seasonality of precipitation and temperature was probably the major factor for the occurrence of wildfires recorded from dark layers. The distribution of wildfires within the profile may be relate to climate changes during the midPiacenzian.
Since our comprehensive investigation of finished drinking water in Germany obtained from managed aquifer recharge systems in the period 2015-2016, which revealed widespread contamination with 1,4-dioxane, mitigation measures (integration of AOP units, shutdown or alteration of production processes) have been implemented at some sites. In this study, we conducted follow-up tests on surface water concentrations and associated finished drinking water concentrations in 2017/2018, to evaluate the effectiveness of these measures. Our findings demonstrate that the emission mitigation measures had considerably reducing effects on the average 1,4-dioxane drinking water concentrations for some of the previously severely affected areas (Lower Franconia:-54%, Passau:-88%). Conversely, at notoriously contaminated sites where neither monitoring nor mitigation measures were introduced, the drinking water concentrations stagnated or even increased. Drinking water concentrations determined via a modified US EPA method 522 ranged from below LOQ (0.034 mu g/L) up to 1.68 mu g/L in all drinking water samples investigated. In river water samples, the maximum concentration exceeded 10 mu g/L. Effluents of wastewater treatments plants containing 1,4-dioxane (5 mu g/L-1.75 mg/L) were also analyzed for other similar cyclic ethers by suspected target screening. Thus, 1,3-dioxolane and three other derivatives were tentatively identified in effluents from the polyester processing or manufacturing industry. 1,3-Dioxolane was present in concentrations >1.2 mg/L at one site, exceeding up to sevenfold the 1,4-dioxane concentration found there. At another site 2-methyl-1,3-dioxolane was still found 13 km downstream of the discharge point, indicating that ethers analogous to 1,4-dioxane should be further considered regarding their occurrence and fate in wastewater treatment and the aquatic environment. (c) 2021 Elsevier B.V. All rights reserved.
This study explores biomarker composition in the sediment record from Lake Lebsko (LL) acting as a representative case of a coastal lake system. The broad context for the research was to provide insights into carbon cycling as well as the origin and transformations of organic C in this unique depositional environment over a long-term perspective. We studied 25 samples from a ca. 9 m long sediment sequence covering the entire Holocene. The samples were analysed with regard to inorganic (TIC, Fe/Mn, Mg/Ca, Al) and organic matter composition (TOC, hydrocarbons, hopanoids, n-alkanols, fatty acids, stanols, sterols etc.) as well as stable C and N isotopes. Our major finding was that the sedimentary organic matter (SOM) in the LL core was predominantly autochthonous albeit highly degraded. The degradation occurred during sedimentation in the water column and/or shortly after deposition and, based on earlier research of coastal lakes, it was related to high water turbulence and sediment mixing. We also found that: (i) higher plant biomarkers were overrepresented in the SOM, and (ii) bulk SOM indicators (e.g., TOC/N, delta C-13(SOM), delta N-15(SOM)) provided more coherent paleoenvironmental information on the lake studied than hydrocarbon and n-alkanol biomarkers. From stable C isotope composition of SOM it emerged that changes in salinity affected the sources of C used for production of autochthonous SOM. During freshwater phases the production of the SOM was mainly fueled by CO2 delivered from the lake catchment while during saltwater periods marine-derived bicarbonates were primarily used for photosynthesis. (C) 2021 Elsevier Ltd. All rights reserved.
The carbon and nitrogen stable isotopic compositions and elemental characteristics of Pliocene pale and dark lignites in the Jinsuo Basin, Yunnan Province, southwestern China, were investigated. These data were used to develop paleoenvironmental models and to discuss possible geological driving forces for the formation of pale and dark layers.The δ13C values of fossil wood (av. −24.79‰) and fusain samples (av. −24.19‰) are generally higher than the values obtained from bulk pale (av. −27.01‰) and dark (av. −26.38‰) lignite samples. In contrast, the δ15N values of fossil wood (av. −0.63‰) and fusain samples (av. 1.29‰) are lower than the average values of bulk pale lignites (av. 2.17‰) and dark lignites (av. 1.79‰). The difference in the carbon isotopic values between pale and dark lignites can be explained by the very high amount of liptinite and strong degradation of woody material by bacterial activity in pale lignites, which resulted in depletion of 13C in pale lignites, and the wet/humid depositional conditions contributed to the relatively heavy stable carbon isotope compositions of dark layers. The higher δ13C values in the fossil wood and fusain samples can be explained by the general enrichment of 13C in woody material compared to leaves. The weakly negative correlation between the δ15N and δ13C values indicates that, besides bacterial degradation, the liptinite content could also influence the carbon and nitrogen compositions of lignites. The influence of the original plant community (gymnosperms/angiosperms) on the carbon and nitrogen isotopic compositions of bulk lignites is insignificant in the Jinsuo Basin.The paleoenvironmental model suggests deposition of pale layers under relatively dry, cold conditions supporting the expansion of gymnosperms such as Pinus yunnanensis. The slight stepwise uplift of the Tibetan Plateau and the approximate co-occurrence of the more intense Asian monsoon might have supported short periods of a locally dry, cold climate resulting in the lowering of water table which was favorable for the formation of pale layers. The low δ13C values in pale layers further support this. The relatively high SiO2/Al2O3 ratios, higher values of the average detrital/authigenic index, and high levels of TiO2 and Zr in pale layers suggest an increased detrital input relative to dark layers. The dark layers, however, formed in a tropical/subtropical warm, humid climate that favored angiosperm dominance of the vegetation. The long-term geologically stable conditions together with the regionally warm, humid climate resulted in a rise in the water table in the basin, which led to the formation of dark layers until the subsequent slight uplift of the Tibetan Plateau. This conclusion is also supported by the high δ13C values in dark layers and the thickness differences between pale (thin) and dark (thick) layers and the changes in major elements and minerals changes between the two types of layer.
Three different lithotypes (xylitic, gelifled and matrix) of Pliocene lignite from the Velenje Basin, Slovenia, were investigated to establish the variations of biomarker compositions in solvent extracts and the stable isotope (carbon and nitrogen) compositions of bulk material. From the biomarker results, the xylitic lithotype almost exclusively originates from gymnosperms (conifers such as Taxodiaceae), as indicated by the very high contents of sesquiterpenoids and diterpenoids but very low abundances of n-alkanes and non-hopanoid triterpenoids. The relative proportion of gymnosperms to angiosperms in the paleomire is reflected by the ratio of diterpenoids to the sum of diterpenoids and non-hopanoid triterpenoids (Di-/(Di- + Tri-terpenoids)), which is close to 1 (av. 0.99) in the xylitic lithotype. The predominance of diterpenoids from conifers in the xylitic lithotype is associated with high C/N ratios and intermediate total sulfur (TS). The very low abundance of hop-17(21)-ene and the absence of further hopanoids in the xylitic lithotype indicate a restricted influence of bacterial degradation under relatively dry conditions in the paleomire. The matrix lithotype also originated preferentially from gymnosperms under dry depositional conditions, as indicated by the high Di-/(Di- + Tri-terpenoids) ratio (0.95), low amounts of hopanoids and low TS content. The gelifled lithotype is characterized by a high content of n-alkanes and wide variation of the Di-/(Di- + Tri-terpenoids) ratio (0.13-0.88), indicating a fluctuating contribution of angiosperms to the plant community in the paleomire during formation of this lithotype. In addition, the high abundance of hop-17(21)-ene and TS in the gelifled lithotype compared with the other two lithotypes suggests the effect of bacterial activity under relatively wet/humid conditions during formation of the gelifled lithotype, which is also supported by the considerable content of mid-chain n-alkanes. The high correlation between the delta C-13 and delta N-15 values (R-2 = 0.68) indicates that the stable carbon and nitrogen isotope composition in the Velenje lignites were probably influenced by the same factors (e.g. precursor plants and/or microbial activity). The stable carbon isotopic values (ay. 25.44%o) and nitrogen isotopic values (av. 2.15%circle) of the xylitic lithotype are higher than those of the gelified lithotype (av. delta C-13 = 27.48%circle, delta N-15 = 1.37%circle) and the matrix lithotype (av. delta C-13 = -27.09%circle, delta N-15 = 1.10%circle). The relatively high correlation between the diterpenoid content and both delta C-13 and delta N-15 values suggests that the stable carbon and nitrogen isotopic composition of the three lithotypes might reflect the composition of the original plant material in the paleomire. The dominance of conifers as precursor plants in the xylitic lithotype might be the main reason for the higher delta C-13 values and probably also the higher delta N-15 values. The relatively higher delta N-15 values in the xylitic lithotype than in the other types could be explained by the high amount of decay-resistant xylem and low mineral (e.g. clay) content in the xylitic lithotype. The slightly lower delta C-13 but higher delta N-15 values in the gelifled lithotype than in the matrix lithotype can be explained by variation of parent plant materials and the influence of bacterial activity.
Global warming is expected to increase the rate of CH4 emission from acidic peatlands leading to an increased interest on its mechanisms of formation. The main routes are through the reduction of CO2 by molecular hydrogen and through the cleavage of acetate. A predominance of the former, a reaction which also competes with homoacetogenesis to form acetate, may enrich the media in acetate, which could potentially be incorporated in the peat molecular markers. Acetates of triterpenoid biomarkers have been identified in peats and lake sediments and related to the input of higher plants. Nevertheless, the acetyl derivatives are found in very low amounts in fresh plants and in much lower amount than other derivatives with alcohol or ketone functional groups. The dichloromethane/methanol extracts of Asturian peat bog profiles (North Spain) were analyzed using gas chromatography/mass spectrometry (GC/MS) and compound-specific-isotope-analysis (CSIA). They show abundance of acetates of compounds with oleanane, ursane, and lupane skeletons derived from higher plants and with hopane skeleton, which can be considered a characteristic of these peats. Two families of 3-oxyhopenyl acetates with -17(21)- and -22(29)- configurations were detected in the upper part of the peat profiles, having a δ13C isotopic composition enriched by 4‰ compared with that of higher plant triterpenoids, and similar to that of microorganism-derived regular hopanoids. Both the acetate and ketone derivatives with the oxygenated functionality at C-3 were generally present in a given extract and tended to accumulate at certain depth in the profiles and in specific levels. The widespread occurrence of acetyl-derivatives, their higher concentration in the deeper layers of the peat, the fact that the acetates correspond to different compound families of diverse source and the very low amount of acetates identified in Ericaceae-contributing to the peat compared to the alcohols suggest that they were formed in the peat under particularly favorable environmental conditions. We postulate that these conditions could have been the existence of a medium enriched in acetic acid produced by the dominance of hydrogenotrophic methanogenesis and/or homoacetogenesis over acetoclastic methanogenesis. This phenomenon that has been preferentially described in Sphagnum bogs at high latitudes, and in the deeper layers of peat, appears to be also present in the temperate peats of the Asturian coast.
Parabens and sorbic acid are commonly used as food preservatives due to their antimicrobial effect. However, their use in foods for infants and young children is not permitted in the European Union. Previous studies found these compounds in some gel-filled baby teethers, whereby parabens, which are well-known as endocrine disruptors, were identified in the polymer-based chewing surface consisting of ethylene-vinyl acetate (EVA). To assess the exposure of infants and young children to these products, the application of parabens in teethers should be thoroughly investigated. Therefore, the present study aimed to apply a representative migration test procedure combined with an accurate analytical method to examine gel-filled baby teethers without elaborate sample preparation, high costs, and long processing times. Accordingly, solid-phase extraction (SPE), in combination with a stable isotope dilution assay (SIDA) and subsequent gas chromatography–mass spectrometry (GC–MS) for analysis of methyl-, ethyl-, and n -propylparaben (MeP, EtP, and n -PrP), was found to be well-suited, with recoveries ranging from 93 to 99%. The study compared the release of these parabens from intact teether surfaces into water and saliva simulant under real-life conditions, with total amounts of detected parabens found to be in the range of 101–162 µg 100 mL −1 and 57–148 µg 100 mL −1 , respectively. Furthermore, as a worst-case scenario, the release into water was examined using a long-term migration study.
1,4-Dioxane, a cyclic ether that has been classified as a class 2B carcinogen by the US-EPA, is a substance of growing environmental concern because of its abundant occurrence in surface waters worldwide. Its high polarity and low biodegradability hamper its retardation in aquifer systems. Previous investigations in Germany have shown that 1,4-dioxane is already widely distributed in rivers and can be found in groundwater at contamination sites. Therefore, the present study shall provide an overview of the Germany-wide distribution of 1,4-dioxane in finished drinking water (FDW) obtained by managed aquifer recharge (MAR) systems. Thus, we investigated the 1,4-Dioxane levels in FDW obtained by MAR, such as river bank filtration (RBF) or artificial groundwater recharge (AGR), in regions that are supplied by surface water bodies (mainly rivers) with already known 1,4-dioxane contaminations. In total, 125 FDW samples and 33 samples of corresponding surface waters were analyzed for 1,4-dioxane content using solid phase extraction followed by gas chromatography-mass spectrometry (SIM-mode) using a slight modification to US-EPA method 522. About 80% of the investigated FDW samples contained 1,4-dioxane at levels exceeding the limit of quantification (0.034 mu g/L); the maximum value was 2.05 mu g/L. However, a maximum concentration of 3 mu g/L was obtained in the surface water samples. Three main factors were associated with elevated levels of 1,4-dioxane in the FDW: A significant 1,4-dioxane contamination of the associated surface water, the application of RBF instead of AGR, and the proportion of available unpolluted groundwater and/or reservoir water blended in the individual waterworks. The results show that 1,4-dioxane should be critically monitored during FDW production by means of MAR not only in Germany. The findings are also of relevance to neighboring countries depending on the same river systems and for research in the field of small mobile substances in drinking water production in general. (C) 2019 Elsevier B.V. All rights reserved.
The complexity of sedimentary organic-matter formation, its source to burial, and influence on bottom-water communities are addressed in this study of the 19 million years-long Upper Cretaceous Tethyan upwelling regime in the Levant. A multi-proxy approach is amalgamated into a model through which the paleoceanographic complexity of an intense and long-lasting upwelling system is better understood. A shift in primary producer assemblages and reorganization of the bottom water bacterial consortium followed the Campanian-Maastrichtian boundary, enforcing conspicuous sedimentological and faunal changes. The siliceous and phosphatic-bearing sediments of the Campanian gave way to Maastrichtian uniform and regionally distributed organic-rich carbonates, accompanied by an increase in sedimentation rates from similar to 1 to > 6 cm/kyr. This has facilitated both the increase in organic-matter production and its excellent preservation, and through diagenetic pathways affected its elemental composition. These paleoceanographic modifications have also affected for-aminiferal assemblages, from massive blooms of triserial (buliminid) benthic foraminifera during the Campanian which have sequestered diatom chloroplasts, to diverse trochospiral forms during the Maastrichtian using nitrate instead of oxygen for their respiratory pathways. We propose that shifts in the type of primary producers promote a change in the amount and type of preserved organic matter, in bottom water communities, on the Ethological composition of the rock-mass, and ultimately on the hydrocarbon generation potential of the studied source rock. The continued rise of southern Tethyan sea level and global highstands during the Upper Maastrichtian, culminating into Arabian Plate-wide maximum flooding surfaces, cause the migration of up welling activity away from the study area, terminating the high productivity sequence in the Levant.
The distributions of organophosphate flame retardants (OPFRs) in various size fractions of indoor dust samples from homes (H; n = 18) and building material markets (B; n = 7) in the Rhine/Main region of Germany were investigated. Three particle size fractions (F1: 150-200 mu m, F2: 63-150 mu m, and F3: <63 mu m) and bulk dust (BD) subsamples (<200 mu m) of each sample were analyzed for 10 OPFRs. On average, the total OPFR concentrations (Sigma 10OPFR) in bulk dust and all three size fractions from building material markets were 133, 153, 196, and 88.0 mu g/g in subsamples B-BD, B-F1, B-F2, and B-F3. These concentrations were at least five times higher than those in bulk dust and all three size fractions from homes, with values of 19.3, 17.2, 19.5, and 18.7 mu g/g for subsamples H-BD, H-F1, H-F2, and H-F3, respectively. Tris(2-chloroisopropyl)phosphate (TCIPP) was the dominant congener in dust from building material markets, contributing over 91% to the Sigma 10OPFR of B-BD and all particle size fractions. Meanwhile, both tris(2-butoxyethyl)phosphate (TBOEP) and TCIPP were abundant in dust from homes, respectively contributing 28%-41% and 31%-43% to the Sigma 10OPFR of H-BD and all particle size fractions. Most of the OPFR concentrations showed no consistent trend with particle size. However, TCIPP was more likely to be enriched in F2. Microscopic examination indicated that TCIPP in indoor dust mainly originated from abraded fragments of commercial products. In contrast, TBOEP accumulated in F3, related to direct transfer of floor-care products to fine dust particles. The concentrations of OPFRs were not significantly correlated with total organic carbon contents in any particle size fraction. However, evaluation of their mass contributions showed that more than 85% of OPFRs accumulated in particles smaller than 150 mu m, indicating that this particle size fraction is most suitable for monitoring of OPFRs. (C) 2018 Elsevier Ltd. All rights reserved.
A set of 39 pale lignite and dark lignite samples, obtained from a profile of the Pliocene Jinsuo lignite basin, Yunnan Province, China, were analyzed using coal petrology and biomarkers to determine whether changes in the depositional environment and/or vegetation caused the color changes ultimately observed in the lignites. A comprehensive analysis of all the data obtained revealed significant differences in the petrological and geo-chemical composition of the two lignite types. The pale lignites are characterized by a higher abundance of the liptinite group compared with the dark lignites. The composition of liptinites is dominated by bituminite (mineral-bituminous groundmass) and sporinite, along with a relatively low abundance of the huminite group. This indicates a higher degree of oxidation in the drier, more elevated peatland environments during deposition of the pale lignites. The low values of the tissue preservation index (TPI), vegetation index (VI), and gelification index (GI) in the pale lignites suggest a relatively high decomposition rate of plant materials under dry/aerobic conditions. In contrast, the dark lignites have a very high proportion of huminite dominated by ulminite, along with a low content of liptinite and inertinite macerals, which suggests the prevalence of wet/anaerobic conditions in the peat-forming mire. The high values of TPI, VI, and GI in the dark layers suggest better preservation of organic matter during deposition under anaerobic conditions, and more wet/humid climatic conditions, when compared with the pale lignites. With respect to the biomarker composition, the high concentrations of long-chain (C-27-C-31) n-alkanes in both pale and dark lignites are typical characteristics for the predominance of higher terrestrial plants. Significant concentrations of mid-chain n-alkanes (n-C-21-C-25) were detected preferentially in the dark lignites, suggesting that aquatic plants might also have contributed to the plant community during the formation of the dark layers. The content of diterpenoids, and the average ratio of diterpenoids to the sum of diterpenoids and triterpenoids (Di-/(Di- + Tri-terpenoids)) are higher in the pale lignites than in the dark lignites. This indicates that gymnosperms made a crucial contribution to the plant community during the formation of the pale lignites. In the dark lignites, triterpenoids are generally far more abundant than diterpenoids, which suggests that the dark layers were overwhelmingly formed by angiosperm plants. This is consistent with lower C/N ratios in the dark lignite layers (ay. 40.8) compared with the pale lignite layers (ay. 60.6). Higher microbial activities in the pale lignites than in the dark lignites are reflected by the higher concentration of hopanoids and 17 alpha,21 beta-homohopane (22R) in the pale lignites.
An effective and sensitive method for the analysis of 1,4-dioxane in water has been available since 2008 (EPA 522). This method is increasingly being applied to investigate the distribution of 1,4-dioxane in the aquatic environment. However, there is a need for more information about the possible occurrence of 1,4-dioxane in groundwater in Europe in general, and in Germany in particular, where virtually no data have been collected so far. The possible contamination of groundwater with 1,4-dioxane is of relevance to Germany because up to 70% of Germany's drinking water is obtained from groundwater and about 17% from river bank filtrate, which contains variable proportions of groundwater. The aim of the present study is to investigate selected and representative groundwater sites in Germany that have suspected occurrences of 1,4-dioxane. Five of the sites are well known for their volatile chlorinated hydrocarbon contamination, two sites have representative landfill leachate characteristics, and one site is negatively impacted by a detergent manufacturing plant. The presence of 1,4-dioxane was observed at each of these sites. Measured maximum concentration values ranged from 0.15μg/L to 152μg/L. An aquifer containing a trichloroethylene (TCE) plume with 1,4-dioxane as a co-contaminant was investigated in more detail. A perfect match was found between the concentrations of 1,4-dioxane and TCE in the vertical and horizontal distribution profiles. The results indicate the necessity for investigating groundwater contamination by 1,4-dioxane at sites with known 1,1,1-trichloroethane (TCA) and TCE contaminations, in landfill leachates, and at sites of detergent production.
The North China Basin is the largest coal-bearing basin in China, and has an areal extent of 800,000 km(2). We analyzed 138 coal samples and in situ pillar coal samples of the middle Permian from this basin by macropetrography, microscope, scanning electron microscope, gas chromatography, and gas chromatography-mass spectrometer in order to study wildfires. High contents of inertinite (charcoal) and natural coke particles observed in coal samples indicate that vegetation in precursor mires and peats of the middle Permian coal from north China was exposed to far-ranging wildfires. In addition, high-molecular-weight polycyclic aromatic hydrocarbons were detected in the coal samples. These aromatic compounds were formed under high temperatures and provide further evidence of wildfire. These wildfires would have discharged significant CO and CO2 gases into the atmosphere and affected the paleoclimate and paleoecosystem.
It is well established that greenhouse conditions prevailed during the Cretaceous Period (~145–66Ma). Determining the exact nature of the greenhouse-gas forcing, climatic warming and climate sensitivity remains, however, an active topic of research. Quantitative and qualitative geochemical and palaeontological proxies provide valuable observational constraints on Cretaceous climate. In particular, reconstructions of Cretaceous sea-surface temperatures (SSTs) have been revolutionised firstly by the recognition that clay-rich sequences can host exceptionally preserved planktonic foraminifera allowing for reliable oxygen-isotope analyses and, secondly by the development of the organic palaeothermometer TEX86, based on the distribution of marine archaeal membrane lipids. Here we provide a new compilation and synthesis of available planktonic foraminiferal δ18O (δ18Opl) and TEX86-SST proxy data for almost the entire Cretaceous Period. The compilation uses SSTs recalculated from published raw data, allowing examination of the sensitivity of each proxy to the calculation method (e.g., choice of calibration) and places all data on a common timescale. Overall, the compilation shows many similarities with trends present in individual records of Cretaceous climate change. For example, both SST proxies and benthic foraminiferal δ18O records indicate maximum warmth in the Cenomanian–Turonian interval. Our reconstruction of the evolution of latitudinal temperature gradients (low, <±30°, minus higher, >±48°, palaeolatitudes) reveals temporal changes. In the Valanginian–Aptian, the low-to-higher mid-latitudinal temperature gradient was weak (decreasing from ~10–17°C in the Valanginian, to ~3–5°C in the Aptian, based on TEX86-SSTs). In the Cenomanian–Santonian, reconstructed latitudinal temperature contrasts are also small relative to modern (<14°C, based on low-latitude TEX86 and δ18Opl SSTs minus higher latitude δ18Opl SSTs, compared with ~20°C for the modern). In the mid-Campanian to end-Maastrichtian, latitudinal temperature gradients strengthened (~19–21°C, based on low-latitude TEX86 and δ18Opl SSTs minus higher latitude δ18Opl SSTs), with cooling occurring at low-, middle- and higher palaeolatitude sites, implying global surface-ocean cooling and/or changes in ocean heat transport in the Late Cretaceous. These reconstructed long-term trends are resilient, regardless of the choice of proxy (TEX86 or δ18Opl) or calibration. This new Cretaceous SST synthesis provides an up-to-date target for modelling studies investigating the mechanics of extreme climates.
The present work describes an analytical method for the analysis of methyl-, ethyl- andn-propylparaben in plastic and gel material from baby teethers filled with cooling gel.
The concentrations of 9 organophosphate flame retardants (OPFRs) were determined in 56 indoor and 9 outdoor air samples in the Rhine/Main area in Germany. The indoor samples were collected from seven different indoor microenvironments including private cars, private homes, floor/carpet stores, building material markets, schools, offices, and day care centers, while outdoor samples were simultaneously collected close to the indoor sampling locations. The total OPFR concentrations (∑OPFRs) in indoor air ranged from 3.30 to 751.0 ng/m3 with a median of 40.23 ng/m3, which was approximately eight times higher than those in outdoor air (median 5.38 ng/m3), indicating that sources of OPFRs predominate in the indoor environment. Tris(2-chloroisopropyl)phosphate (TCPP), tris(isobutyl)phosphate (TiBP), and tributyl phosphate (TnBP) were the dominating compounds both in indoor and outdoor air. The median concentration of ∑OPFRs in private cars (180.3 ng/m3) was significantly higher than that in private homes (12.51 ng/m3), schools (36.23 ng/m3), day care centers (31.80 ng/m3), and building material markets (31.17 ng/m3) (p < 0.05). Distribution profiles of OPFRs varied among different indoor microenvironments, which are evidenced by dominating indoor air concentrations of non-Cl-OPFRs in day care centers, floor/carpet stores, schools, and of Cl-OPFRs in other indoor microenvironments. Multivariate analyses revealed three distinct groups for OPFRs, i.e., TiBP/TnBP, TEP/TCEP/TDCPP, and TCPP, whose concentrations were closely associated with the distribution profiles and pollution characteristics of materials predominating in different indoor microenvironments.
Abstract. It has generally been argued that the majority of fossil benthic foraminifera, the most common proxy for paleo bottom oceanic conditions, could not tolerate anoxia. Here we present evidence that fossil foraminifera were able to successfully colonize anoxic-dysoxic bottom waters, by using adaptations similar to those found in living species. Our study is based on a multi proxy micropaleontological and geochemical investigation of the Upper Cretaceous sediments from the Levant upwelling regime. A shift from buliminid to diverse trochospiral dominated assemblages was recorded in an interval with a distinct anoxic geochemical signature coinciding with a regional change in lithology. This change was triggered by an alteration in the type of primary producers from diatoms to calcareous nannoplankton, possibly causing modifications in benthic foraminiferal morphological and physiological adaptations to life in the absence of oxygen. Our data show that massive blooms of triserial (buliminid) benthic foraminifera with distinct apertural and test morphologies during the Campanian were enabled by their ability to sequester diatom chloroplasts and associate with bacteria, in a similar manner as their modern analogs. Diverse trochospiral forms existed during the Maastrichtian by using nitrate instead of oxygen for their respiratory pathways in a denitrifying environment. Species belonging to the Stilostomellidae and Nodosariidae families might have been affected by the change in food type arriving to the seafloor after the phytoplankton turnover at the Campanian/Maastrichtian boundary, in a similar manner as their mid Pleistocene descendants prior to their extinction. This study promotes the need for a re-evaluation of the current models used for interpreting paleoceanographic data and demonstrates that the identification of adaptations and mechanisms involved in promoting sustained life under anoxic to dysoxic conditions should become a standard in faunal paleoceanographic studies.
A 102m long core section of the late Eocene Kiliran Jao oil shale has been studied by means of palynofacies and inorganic geochemistry to examine the role of climate change on the development of the Kiliran Jao paleo-lake. Climate changes during deposition of the studied oil shale are interpreted from the abundance variation of fungal remains. Higher abundance of fungal remains in the middle part of the oil shale profile indicates relatively warmer climate during deposition. The warmer climate is thought to have led to changes in lake productivity. Carbon isotopic compositions of organic matter (δ13C) range from −27.0 to −30.5‰. These are generally more depleted in the middle part of the profile indicating lower primary productivity of the lake during deposition. Botryococcus braunii varies from 3 to 16% and is generally more abundant in the middle part of the profile. This is consistent with the less trophic preference of this algal blooming. The warmer climate is thought to have induced stratification, limiting the introduction of recycled nutrients to the epilimnion, thereby reducing the lake productivity.