Aliphatic biomarker signatures of early Oligocene-early Miocene source rocks in the central Qiongdongnan Basin:Source analyses of organic matter

The geochemical signatures of fifty-four rock samples and three supplementary drill stem test(DST)oils from the Yacheng-Sanya formations in the central Qiongdongnan Basin(CQB)were analysed.Reconstruction of the early Oligocene-early Miocene(36–16 Ma)palaeovegetation and source analyses of organic matter(OM)were conducted using aliphatic biomarkers in ancient sediments and DST oils.Both the interpreted aquatic and terrigenous OM contributed to the CQB source rocks(SRs)but had varying relative proportions.The four distribution patterns derived from n-alkanes,terpanes,and steranes are representative of four OM composition models of the Yacheng-Sanya SRs,including model A,model B,model C,and model D,which were classified based on the increasing contribution from terrigenous OM relative to aquatic OM.Some terrigenous higher plantderived biomarkers,including oleanane,des-A-oleanane,C_(29)ααα20R sterane,bicadinanes,the C_(19)/(C_(19)+C_(23))tricyclic terpane ratio,and other n-alkane-derived ratios suggest that angiosperms had increased proportions in the palaeoflora from early Oligocene to early Miocene,and the bloom of terrigenous higher plants was observed during deposition of upper Lingshui Formation to lower Sanya Formation.These findings are consistent with the incremental total organic carbon and free hydrocarbons+potential hydrocarbons(S_1+S_2)in the lower Lingshuilower Sanya strata with a significant enrichment of OM in the E_3l_1-N_1s_2 shales.The maturity-and environmentsensitive aliphatic parameters of the CQB SRs and DST oils suggest that all the samples have predominantly reached their early oil-generation windows but have not exceeded the peak oil windows,except for some immature Sanya Formation shales.In addition,most of the OM in the analysed samples was characterised by mixed OM contributions under anoxic to sub-anoxic conditions.Furthermore,terrestrial-dominant SRs were interpreted to have developed mainly in the Lingshui-Sanya formations and were deposited in sub-oxic to oxic environments,compared to the anoxic to sub-anoxic conditions of the Yacheng Formation.

Identifying the sources of organic matter in marine and riverine sediments of Bohai Bay and its catchment using carbon and nitrogen stable isotopes

Carbon and nitrogen stable isotopes are useful tracers for distinguishing marine and terrestrial plant sources of sedimentary organic matter(OM),and for identifying OM from different types of plants.By analyzing the carbon and nitrogen stable isotopes of marine and riverine sediments from Bohai Bay and its catchment,we were able to identify the source of OM in these sediments.The stable carbon isotope values of Bohai Bay sediments were between-22.94‰ and-23.90‰,while those of riverine sediments were from-24.45‰ to-32.50‰.Marine algae were the main source of OM in Bohai Bay sediments.However,lacustrine algae were the main source of riverine sediments,not terrestrial OM.The nitrogen isotopes in Bohai Bay sediments decreased in eastward direction,with increasing distance from the coastline,which suggested a higher degree of impact from human activities along the coast.

Biomarker assessments of sources and environmental implications of organic matter in sediments from potential cold seep areas of the northeastern South China Sea

Multi-biomarker indexes were analyzed for two piston cores from potential cold seep areas of the South China Sea off southwestern Taiwan. Total organic carbon（TOC） normalized terrestrial（n-alkanes） and marine（brassicasterol, dinosterol, alkenones and iso-GDGTs） biomarker contents and ratios（TMBR, 1/Pmar-aq, BIT） were used to evaluate the contributions of terrestrial and marine organic matter（TOM and MOM respectively） to the sedimentary organic matter, indicating that MOM dominated the organic sources in Core MD052911 and the sedimentary organic matter in Core ORI-_（86）0-22 was mainly derived from terrestrial inputs, and different morphologies were the likely reason for TOM percentage differences. BIT results suggested that river-transported terrestrial soil organic matter was not a major source of TOM of sedimentary organic matter around these settings.Diagnostic biomarkers for methane-oxidizing archaea（MOA） were only detected in one sample at 172 cm depth of Core ORI-_（86）0-22, with abnormally high iso-GDGTs content and Methane Index（MI） value（0.94）. These results indicated high anaerobic oxidation of methane（AOM） activities at or around 172 cm in Core ORI-_（86）0-22.However in Core MD052911, MOA biomarkers were not detected and MI values were lower（0.19–0.38）, indicated insignificant contributions of iso-GDGTs from methanotrophic archaea and the absence of significant AOM activities. Biomarker results thus indicated that the discontinuous upward methane seepage and insufficient methane flux could not induce high AOM activities in our sampling sites. In addition, the different patterns of TEX_（86） and U_（37）^（K′） temperature in two cores suggested that AOM activities affected TEX_（86）37 temperature estimates with lower values in Core ORI-_（86）0-22, but not significantly on TEX_（86） temperature estimates in Core MD052911.

Sources and transport of particulate organic carbon in the Amazon River and its estuary

Stable carbon isotope ratios have been used to study the sources of particulate organic carbon(POC) in the Amazon River and its tributaries, and to examine the transport of the riverine POC intothe oceanic environment. POC in the upper reaches of the Amazon River has more positive δC values(--24.5‰ to -- 28.0‰) than that in the middle and lower reaches (--27.9‰ to -- 30.1‰). TheδC of POC from the tributaries is generally more negative than that observed in the Amazon mainchannel. This δC datum shows that the POC in the Amazon main channel is predominantly of terres-trial origin rather than a result of in situ production. A large range of δC values (--17.5‰ to -28.4‰) is observed in the Amazon Estuary and plume. and is considered as the result of the mixing

Influence of Organic and Inorganic Nitrogen on Grain Yield andYield Components of Hybrid Rice in Northwestern Pakistan

Field experiments were conducted to assess the impact of various organic sources, inorganicnitrogen （N） and the different combinations of inorganic N （urea） ＋ organic source on the yieldcomponents （YC） and grain yield （GY） of hybrid rice （Oryza sativa L., Pukhraj） under rice-wheat system.The experiments were conducted at Batkhela （Malakand）, Northwestern Pakistan, in 2011 and 2012.Our results revealed that YC and GY ranked first for the hybrid rice when applied with sole inorganic N（urea）, followed by the application of N in mixture （urea ＋ organic sources）, while the control plots （no Napplied） ranked in the bottom. Among the six organic sources （three animal manures： poultry, sheepand cattle; three crop residues： onion, berseem and wheat）, application of N in the form of poultrymanure was superior in terms of higher YC and GY. When applying 120 kg/hm2 N source, 75% N fromurea ＋ 25% N from organic source resulted in higher YC and GY in 2011, while applying 50% N fromurea ＋ 50% N from organic sources caused higher YC and GY in 2012. Therefore, the combinedapplication of N sources in the form of urea ＋ organic source can produce good performances in termsof higher YC and GY of rice under rice-wheat cropping system.

Spatiotemporal variations in the organic carbon accumulation rate in mangrove sediments from the Yingluo Bay,China,since 1900

Mangroves can not only provide multiple ecosystem service functions,but are also efficient carbon producers,capturers,and sinks.The estimation of the organic carbon accumulation rate(OCAR)in mangrove sediments is fundamental for elucidating the role of mangroves in the global carbon budget.In particular,understanding the past changes in the OCAR in mangrove sediments is vital for predicting the future role of mangroves in the rapidly changing environment.In this study,three dated sediment cores from interior and fringe of mangroves in the Yingluo Bay,China,were used to reconstruct the spatiotemporal variations of the calculated OCAR since 1900 in this area.The increasing OCAR in the mangrove interior was attributed to mangrove flourishment induced by climate change characterized by the rising temperature.However,in the mangrove fringe,the strengthening hydrodynamic conditions under the sea level rise were responsible for the decreasing OCAR,particularly after the1940 s.Furthermore,the duration of inundation by seawater was the primary factors controlling the spatial variability of the OCAR from the mangrove fringe to interior,while the strengthened hydrodynamic conditions after the 1940 s broke this original pattern.

Aerosol composition,sources,and secondary processing during autumn at a regional site in the Beijing-Tianjin-Hebei region

Air pollution is serious during autumn in the Beijing-Tianjin-Hebei(BTH)region,but there are few studies that have utilized real-time observations and source apportionment of the autumn submicron aerosols in this region.In this study,a quadrupole aerosol chemical speciation monitor(Q-ACSM)was deployed for the real-time measurement of the non-refractory compositions of submicron aerosols(NR-PM1)at a regional site(Xianghe)from October 3 to November 14,2017.The results showed that nitrate was the largest inorganic aerosol,and the oxygenated organic aerosol(OOA)was the largest organic aerosol in Xianghe.Hydrocarbon-like OA(HOA)was the largest organic aerosol When the NR-PM1 mass concentrations increased from the lowest to the highest bins,nitrate and biomass burning OA(BBOA)showed increasing trends in the suburban area.Enhanced nitrate formation during the pollution epi-sodes resulted from both photochemical and aqueous processing.To reduce the particulate matter(PM2.5)concentrations and eliminate heavy pollution episodes,control measures should focus on reducing NO_(x),NH_(3),and volatile organic compound(VOCs)emissions.

Conjugate Hydrocyanation of Chalcone Derivatives Using Ethyl Cyanoacetate as an Organic Cyanide Source

The conjugate hydrocyanation of chalcone derivatives using ethyl cyanoacetate as an organic cyanide source at room temperature under open air and transition metal-free conditions was described. The protocol has advantages of using relatively cheap, less toxic, stable and easy-to-handle cyanating reagent, high yield, and mild reaction condi- tion.

Compositions and sources of organic acids in fine particles(PM_(2.5)) over the Pearl River Delta region, south China

Organic acids as important constituents of organic aerosols not only influence the aerosols＇ hygroscopic property, but also enhance the formation of new particles and secondary organic aerosols. This study reported organic acids including C14-C32 fatty acids, C4-C9 dicarboxylic acids and aromatic acids in PM2.5 collected during winter 2009 at six typical urban, suburban and rural sites in the Pearl River Delta region. Averaged concentrations of C14-C32 fatty acids, aromatic acids and C4- C9 dicarboxylic acids were 157, 72.5 and 50.7 ng/m3, respectively. They totally accounted for 1.7% of measured organic carbon. C20-C32 fatty acids mainly deriving from higher plant wax showed the highest concentration at the upwind rural site with more vegetation around, while Cl4-C18 fatty acids were more abundant at urban and suburban sites, and dicarboxylic acids and aromatic acids except 1,4-phthalic acid peaked at the downwind rural site. Succinic and azelaic acid were the most abundant among C4-C9 dicarboxylic acids, and 1,2-phthalic and 1,4-phthalic acid were dominant aromatic acids. Dicarboxylic acids and aromatic acids exhibited significant mutual correlations except for 1,4-phthalic acid, which was probably primarily emitted from combustion of solid wastes containing polyethylene terephthalate plastics. Spatial patterns and correlations with typical source tracers suggested that C14-C32 fatty acids were mainly primary while dicarboxylic and aromatic acids were largely secondary. Principal component analysis resolved six sources including biomass burning, natural higher plant wax, two mixed anthropogenic and two secondary sources; further multiple linear regression revealed their contributions to individual organic acids. It turned out that more than 70% of C14-C18 fatty acids were attributed to anthropogenic sources, about 50%-85% of the C20-C32 fatty acids were attributed to natural sources, 80%-95% of dicarboxylic acids and 1,2-phthalic acid were secondary in contrast with that 81% of 1,4-phthalic acid was primary.

Molecular characterization of effluent organic matter in secondary effluent and reclaimed water:Comparison to natural organic matter in source water

Municipal wastewater reclamation is becoming of increasing importance in the world to solve the problem of water scarcity. A better understanding of the molecular composition of effluent organic matter（Ef OM） in the treated effluents of municipal wastewater treatment plants（WWTPs） is crucial for ensuring the safety of water reuse. In this study, the molecular composition of Ef OM in the secondary effluent of a WWTP in Beijing and the reclaimed water further treated with a coagulation–sedimentation–ozonation process were characterized using a non-target Fourier transform ion cyclotron resonance mass spectrometry（FT-ICR MS） method and compared to that of natural organic matter（NOM） in the local source water from a reservoir. It was found that the molecular composition of Ef OM in the secondary effluent and reclaimed water was dominated by CHOS formulas, while NOM in the source water was dominated by CHO formulas. The CHO formulas of the three samples had similar origins. Anthropogenic surfactants were responsible for the CHOS formulas in Ef OM of the secondary effluent and were not well removed by the coagulation-sedimentation-ozonation treatment process adopted.

Multivariate modular metabolic engineering and medium optimization for vitamin B_(12)production by Escherichia coli

Vitamin B_(12)is a complex compound synthesized by microorganisms.The industrial production of vitamin B_(12)relies on specific microbial fermentation processes.E.coli has been utilized as a host for the de novo biosynthesis of vitamin B_(12),incorporating approximately 30 heterologous genes.However,a metabolic imbalance in the intricate pathway significantly limits vitamin B_(12)production.In this study,we employed multivariate modular metabolic engineering to enhance vitamin B_(12)production in E.coli by manipulating two modules comprising a total of 10 genes within the vitamin B_(12)biosynthetic pathway.These two modules were integrated into the chromosome of a chassis cell,regulated by T7,J23119,and J23106 promoters to achieve combinatorial pathway optimization.The highest vitamin B_(12)titer was attained by engineering the two modules controlled by J23119 and T7 promoters.The inclusion of yeast powder to the fermentation medium increased the vitamin B_(12)titer to 1.52 mg/L.This enhancement was attributed to the effect of yeast powder on elevating the oxygen transfer rate and augmenting the strain’s isopropyl-β-D-1-thiogalactopyranoside(IPTG)tolerance.Ultimately,vitamin B_(12)titer of 2.89 mg/L was achieved through scaled-up fermentation in a 5-liter fermenter.The strategies reported herein will expedite the development of industry-scale vitamin B_(12)production utilizing E.coli.

Source apportionment of atmospheric particulate carbon in Las Vegas,Nevada,USA

A study was conducted to quantify wintertime contributions of source types to carbonaceous PM2.5 at four urban sites in the Las Vegas Valley, one of the most rapidly growing urban areas in the southwestern United States. Twenty-four hour average ambient samples were collected for mass, ions, elements, organic carbon （OC）, elemental carbon （EC）, and trace organic markers analysis. Additional measurements were made to determine diurnal patterns in light-absorbing black carbon （BC） as a marker for combustion sources. Carbonaceous PM sources of on-road gasoline vehicles, on-road diesel vehicles, and off-road diesel engines were characterized with their chemical profiles, as well as fuel-based emission factors, using an In-Plume Sampling System. The Effective Variance Chemical Mass Balance （EV-CMB） source apportionment model was applied to the ambient samples collected, using source profiles developed in this study as well as profiles from other relevant studies. Four main sources contributed to PM2.5 carbon within the Las Vegas Valley： （1） paved road dust, （2） on-road gasoline vehicles, （3） residential wood combustion, and （4） on-road diesel vehicles. CMB estimated that on-road mixed fleet gasoline vehicles are the largest source for OC and EC at all the sites. The contribution of paved road dust to both OC and EC was 5-10% at the four sites. On-road diesel vehicles contribute 22% of the OC and 34% of the EC at a site near the city center, which is located immediately downwind of a major freeway. Residential wood combustion is a more important source than on-road diesel vehicles for two residential neighborhood sites, These results are consistent with our conceptual model, and the research methodology may be applied to studying other urban areas.

Characterization of submicron particles during autumn in Beijing,China

In this study, we performed a highly time-resolved chemical characterization of nonrefractory submicron particles（NR-PM_1） in Beijing by using an Aerodyne high-resolution time-of-flight aerosol mass spectrometer（HR-ToF-AMS）. The results showed the average NR-PM_1 mass concentration to be 56.4 ± 58.0 μg/m^3, with a peak at 307.4 μg/m^3. Due to the high frequency of biomass burning in autumn, submicron particles significantly increased in organic content, which accounted for 51% of NR-PM_1 on average. Secondary inorganic aerosols（sulfate ＋ nitrate ＋ ammonium） accounted for 46% of NR-PM_1, of which sulfate,nitrate, and ammonium contributed 15%, 20%, and 11%, respectively. To determine the intrinsic relationships between the organic and inorganic species, we used the positive matrix factorization（PMF） model to merge the high-resolution mass spectra of the organic species and NO＋and NO_2~＋ions. The PMF analysis separated the mixed organic and nitrate（NO＋and NO_2~＋） spectra into four organic factors, including hydrocarbon-like organic aerosol（HOA）, oxygenated organic aerosol（OOA）, cooking organic aerosol（COA）, and biomass burning organic aerosol（BBOA）, as well as one nitrate inorganic aerosol（NIA） factor. COA（33%） and OOA（30%） contributed the most to the total organic aerosol（OA） mass, followed by BBOA（20%） and HOA（17%）. We successfully quantified the mass concentrations of the organic and inorganic nitrates by the NO＋and NO2＋ions signal in the organic and NIA factors. The organic nitrate mass varied from 0.01-6.8 μg/m^3, with an average of 1.0 ±1.1 μg/m^3, and organic nitrate components accounted for 10% of the total nitrate mass in this observation.

Distribution of fatty acids in the alpine grassland soils of the Qinghai-Tibetan Plateau

As an important biomarker, fatty acids(FAs) have been extensively used to trace the origin of organic matter in sediments and soils. However, studies of the distribution and abundance of FAs in alpine grassland soils are still rare, especially on the Qinghai-Tibetan Plateau(QTP), the highest plateau in the world, which contributes sediments to many large rivers in Asia. This study investigates the composition, distribution and source of FAs with increasing soil depths from 17 typical alpine grassland sites in the QTP. The most abundant FAs included the ubiquitous C16 FA and even-numbered long-chain FAs(C20–C30), indicating mixed inputs from microbial and higher plant sources. Source apportionment showed that higher plants were the dominant contributor of FAs(approximately 40%) in QTP soils. The abundance of FAs decreased with soil depth, with the highest value(1.08±0.09 mg/g C) at a 0–10 cm depth and the lowest value(0.46±0.12 mg/g C) at a 50–70 cm depth, due to much lower plant inputs into the deeper horizons. The total concentration of FAs was negatively correlated to the mean annual temperature(MAT; P<0.05) and soil p H(P<0.01), suggesting that the preservation of FAs was favored in low-MAT and low-p H soils on the QTP. The abundance of fresh C source FAs increased significantly with the mean annual precipitation(MAP; P<0.05), indicating that high MAP facilitates the accumulation of fresh FAs in QTP soils. Other environmental parameters, such as the soil mineral content(aluminum and iron oxide), microbial community composition as well as litter quality and quantity, may also exert a strong control on the preservation of FAs in QTP soils and warrant further research to better understand the mechanisms responsible for the preservation of FAs in QTP soils.