Plant Organic Matter Research Articles

Age-Dating of Foliage and Soil Organic Matter: Aligning 228Th:228Ra and 7Be:210Pb Radionuclide Chronometers over Annual to Decadal Time Scales.

The 228Th:228Ra ratios of foliage and organic soil horizons evolve with time following a predictable radioactive decay law and thus provide a new chronometer for absolute age-dating of plant and soil organic matter. Preferential uptake of 228Th (t0.5 = 1.9 years) and 228Ra (t0.5 = 5.9 years) by canopy tree species, ferns, and mosses, drives disequilibrium in the 232Th-228Ra-228Th radioactive decay series within forest vegetation and organic soils. With examples from northeastern USA, we verify a new 228Th:228Ra age model by demonstrating its concordance with the fallout radionuclide chronometer 7Be:210Pb in the 0 to 5-year time frame [R2 = 0.87, RMSE = 0.5 years]. At our locality, canopy tree species assimilate 228Th with a typical initial ratio (228Th:228Ra)0 ∼ 0.3, but in several instances, both deciduous and coniferous tree species show a preference for Th over Ra with (228Th:228Ra)0 exceeding 5. While the 228Th:228Ra system is restricted to organic soil horizons, concordance of 228Th:228Ra with established 7Be:210Pb and 241Am bomb-pulse chronometers establishes a coherent age-dating system of soil organic matter based on three independent chronometers and five particle reactive metals, and spanning 0-200 years in time scale that encompasses both organic and mineral soils to depths of up to 30 cm. Concordance indicates that these metals all follow common processes of organometallic colloid formation and migration and, in conjunction with 14C, may open new opportunities to understand soil pedogenic processes that regulate the storage of carbon and atmospheric metals such as Pb and Hg.

Source, Distribution and Transformation of Organic Matter in a Subtropical Karst Reservoir

In order to improve the understanding of the global carbon cycle and the stability of karst carbon sinks, it is necessary to better understand the source, distribution and transformation characteristics of organic matter (OM) in aquatic ecosystems. Here, stable isotope ratios (δ13C and δ15N), elemental analysis (C/N ratios), and lipid biomarkers were analyzed for dissolved organic matter (DOM) (<0.7 μm), particulate organic matter (POM) (>0.7 μm) of water, and organic matter from sediment cores (SCOM) to identify the sources, distribution, and transformation of OM in a subtropical karst reservoir. The results showed that short-chain (C14–20) n-alkyl lipids were more abundant than long-chain (C21–34) n-alkyl lipids in both the DOM and SCOM samples, indicating that bacteria were the primary sources of these lipids, while terrestrial organic matter (OM) made only a minor contribution to the n-alkyl lipid pool, and aquatic plants (macrophytes) OM contributed major contribution to the n-alkyl lipid pool in POM. Microbial activity and lipid degradation were more pronounced in the DOM. Furthermore, terrigenous and macrophyte-derived lipids were found to be more abundant in POM than in DOM and SCOM, suggesting that they are relatively resistant to degradation compared with phytoplankton-derived OM.

Organic matter characteristics and gas generation prospect of the Late Cretaceous fluvial deltaic organic‐rich shale in the offshore Jiza‐Qamar Basin, Yemen based on organic geochemical, macerals composition, and biomarker results combined with 1‐D basin modelling

Organic‐rich shale samples of the Late Cretaceous Mukalla Formation from the Al‐Fatk1 well in the offshore Jiza‐Qamar Basin, eastern Yemen, were examined using bulk organic geochemistry, microscopic examination, and biomarker measurements combined with 1‐D basin modelling, to evaluate the organic matter characteristics and their ability to generate gas. The studied Mukalla shale samples are characterized by their high organic matter content with total values of up to 14.50 wt.%, and contain mainly hydrogen‐poor Type III kerogen, indicating elevated gas generation potential. The hydrogen‐poor kerogen was also demonstrated by biomarker measurements combined with an abundance of land‐derived organic matter (i.e., vitrinite and inertinite) as established by microscopic investigation. The biomarkers of the studied organic‐rich shales were characterized by a high Pr/Ph ratio, abundance of C29 regular steranes, high C27 17α (H)‐22, 29, 30‐trisnorhopane compared with C27 18α (H)‐22, 29, 30‐trisnorneohopane, all providing evidence for the organic matter being derived primarily from higher land plant organic matter, deposited in fluvial deltaic environments under highly oxic conditions. The bulk carbon isotope data agree with the findings of terrigenous organic matter. The maturity indicators show that the examined organic‐rich shale samples have entered the main oil stage and are at the beginning of wet gas generation windows, exhibiting vitrinite reflectance values that range between 0.73% and 1.20%. Kerogen to gas conversion has been simulated by the basin models and shows that between 10% and 15% of kerogen has transformed into gas during the late Miocene until the present‐day, consistent with the wet gas generation window (1.00–1.20 %Ro). Substantial gas exploration potential may exist in the fluvial deltaic Mukalla source rock system in the deeper structural units of the Qamar‐Jiza Basin, where the Mukalla Formation has reached the high maturity level of the gas generation window.

Litter-Mediated Soil Alterations by Guinea Grass (Megathyrsus maximus) in Semiarid Rangelands

Invasive plants are regarded as both drivers and passengers of change in the ecosystems they invade. In both conditions, these plants are reported to cause significant changes in soil biological, physical, and chemical characteristics, which have a long-lasting impact in the invaded soils compared with the surrounding uninvaded soils. One of the mechanisms of such change is the addition of both aboveground and belowground plant organic material. The goal of this study was to explore the plant-soil feedback in a non-native invasive grass, Guinea grass (Megathyrsus maximus) that invades rangelands, agricultural fields, and natural areas in the tropics and warm temperate regions. We hypothesized that the soil under Guinea grass is significantly different from natives. We also hypothesized that high tissue nitrogen leads to a higher litter nutrient status, driving this change. To test these hypotheses, we selected five different sites with significant Guinea grass invasion history and analyzed the soils under Guinea grass and coexisting native grasses. Our results show there was no significant difference between Guinea grass and natives in the amount of organic matter in the soil, but the nitrogen (N) content in both soil and leaf tissue in Guinea grass and natives was significantly different. The higher N content in the leaves was strongly correlated with soil N, moisture, and organic matter salinity, and negatively correlated with soil pH. Therefore, our results show that due to its nitrogen-rich leaf tissues, Guinea grass adds higher-quality litter back into the soil, resulting in a higher nutrient pool in its rhizosphere compared with the native grasses, thereby further aiding in the invasion success of Guinea grass.

Изучение вопроса о закупке красящих композиционных материалов на основе неорганического и органического сырья

The article states that one of the biggest problems of modern agriculture is to prevent the irreversible loss of fertile land on earth and to provide agriculture with new land. In this regard, it has become an urgent problem to use natural resources efficiently and restore damaged lands with various means and methods. In the studies conducted to solve the problem, the process of obtaining composite materials with fertilizer-ameliorant properties, which is of particular importance in increasing soil productivity and plant height, using inorganic and organic raw materials, was studied. It has been established that only applying fertilizers to ecologically damaged soils does not give positive results, because the structure and physical-chemical properties of the soils are damaged, and complex measures must be taken to restore them. The more intensive feeding of the plant with phosphorus with the participation of the magnesium element leads to the formation of water-resistant aggregates, which, as a result, percolation and infiltration decrease, and the amount of available phosphorus in the soil increases.

CARBON AND NITROGEN CONTENT AND RESERVES IN TERRESTRIAL ECOSYSTEMS OF THE MURMANSK REGION

The article provides an overview of own and literature data on phytomass reserves, carbon and nitrogen content, diversity of soil fauna and mycobiota in terrestrial ecosystems of the Murmansk region under conditions of combined action of natural and anthropogenic factors. The environmental factors determining the functioning of ecosystems, including the regulation of carbon cycles, are considered. It is shown that in representative spruce and pine forests, the concentrations and precipitation of carbon compounds from the atmosphere and its removal from soil waters are higher in the subcron spaces than in the intercron spaces. In soil waters, there is a decrease in carbon removal with the depth of the soil profile. The podzols are characterized by a bimodal distribution of humus over the soil profile with maxima in the organogenic and illuvial horizons. The carbon content in the organogenic horizon of the soils of spruce and pine forests varies from 12 to 54%, nitrogen — from 4.7 to 18.7 g/kg. The main carbon reserves in the organogenic horizon of forest soils are concentrated in the sub-crown spaces and reach 27–34 t/ha. Carbon reserves in the meter layer of soil (mineral horizons) are 47–60 t/ha. The phytomass reserves of the North taiga forests are characterized by low values (12–188 t/ha). Significant reserves of plant organic matter of the North Taiga forests are concentrated in the ground cover. The carbon content in the assimilating organs (leaves/needles, shoots) of plants of the North Taiga forests varies from 35 to 73%, nitrogen — from 5.4 to 23.6 g/kg. The rate of decomposition of plant residues and carbon loss during the decomposition of the fall of evergreen plants in spruce forests is higher than in pine forests, as are the indicators of the number of soil macrofauna. The podzols of the North Taiga forests correspond to the predominance of secondary destroyers of plant litter — humifiers of earthworms and mixophages wireworms, litter mollusks) and the absence of calcifilic groups of mineralizers (woodlice, bipedal millipedes). 122 species of microscopic fungi have been isolated from the soils of the Murmansk region. Species of pp. Penicillium and Umbelopsis were dominant in terms of abundance in the background soil, in anthropogenically altered soils — species of pp. Aureobasidium, Penicillium, Trichocladium, Trichoderma and Umbelopsis.

Use of biomass for biofuel production

Plant biomass is the largest renewable energy source. Republic of Srpska and the Republic of Serbia are among the top European countries in terms of the amount of available and unused biomass. Biogas is a product obtained by anaerobic decomposition of organic matter with the help of a complex of microorganisms in biogas power plants. All types of biomass which contains carbohydrates, proteins, fats, cellulose and hemicellulose can be used to obtain biogas. In theoretical terms, biogas can be produced from any substrate of organic origin. Also, there are possibilities to combine different types of substrates in one biogas plant. However, there are technical or economic limitations to this, which is why it is best to use several types of substrates of different origins in practice. Depending on the physical state, substrates are divided into solid and liquid. Liquid substrates include sewage and various wastewaters with a significant content of organic matter, while solid substrates include manure, various types of silage, food waste, solid organic municipal waste and other types of organic waste. The special importance of the production and use of biogas, as a type of renewable energy source, is the prevention of emissions of methane, a gas that increases the greenhouse effect (the intensity is 23 times higher than carbon dioxide). Also, the use of biogas as a fuel, most often produces electricity, and thus contributes to the realization of the set goals of greater use of renewable energy sources. An additional positive impact is the reduction of the spread of unpleasant odors, prevention of soil and groundwater pollution. Positive socioeconomic effects are also being achieved, rural development is being encouraged, and human and material resources are being used better at the local level. When studying the possibilities of biogas production, the quantities and prices of individual substrates are first considered. Their characteristics are analyzed, which determine the potential for biogas production, and thus the size of the biogas plant. Only a small part of the liquid and solid biomass in the fermentation plant is transformed into biogas. The rest of this process needs to be taken care of and used in an adequate way. The rest of the fermentation is aby-product in the production of biogas, and it is most often used as a fertilizer. It contains plant nutrients and organic matter, and by returning to agricultural areas, it contributes to preserving the fertility of the land. One of the ways to use the rest of the fermentation is to produce pellets or briquettes after separation and drying, and to use it as a solid fuel. Thanks to the development of new technologies for processing bio-waste into energy, the rate of increase in the use of alternative fuels is growing significantly.

Anthropogenically driven changes to organic matter input in sediments of Lake Chaohu, Eastern China, over the past 166 years

Characterizing how and to what extent human activities have influenced organic matter (OM) input in lake sediments is essential for a thorough study of the carbon cycle and carbon burial in lake systems, but this issue has not yet been addressed. Here, the source and composition of OM in sediments of Lake Chaohu, Eastern China, over the past 166 years, were determined by analyzing stratigraphic variations in aliphatic hydrocarbons and OM pyrolysis parameters in a dated sediment core. These data, coupled with documental records, were further used to elucidate the pattern and controlling factors of OM input in the sediments. The lowest hydrogen index (HI), lowest long-chain n-alkane concentrations, and highest Paq (proxy of aquatic macrophyte input) in sediments prior to ca. 1956 indicate a minimal input of OM from phytoplankton and terrestrial plants and a larger input from submerged macrophytes. This may represent the features of OM input in primitive conditions given the mild human activities around the lake before the 1950s. In sediments from ca. 1962 to 1985, elevated HI and C17/C16n-alkane ratios indicate a greater input from phytoplankton, while the high abundances of long-chain n-alkanes and αβ-hopanes reflect an anomalously high input from terrestrial plant and fossil OM. These variations might have been caused by the rapid development of agriculture during this period, which accelerated catchment erosion and petroleum contamination and promoted the transport of allochthonous OM and nutrients to the lake. The lowest Paq in sediments during this period indicates reduced input from submerged macrophytes, probably resulting from a dam installation that modified the water to an unfavorable plant depth. In sediments after ca. 1989, the highest values of HI, short-chain n-alkane abundances, and C17/C16n-alkane ratios indicate a further increase in OM input from phytoplankton, a response to domestic and industrial discharge and subsequent lake eutrophication.

Updating the dual C and O isotope-Gas-exchange model: A concept to understand plant responses to the environment and its implications for tree rings.

The combined study of carbon (C) and oxygen (O) isotopes in plant organic matter has emerged as a powerful tool for understanding plant functional responses to environmental change. The approach relies on established relationships between leaf gas exchange and isotopic fractionation to derive a series of model scenarios that can be used to infer changes in photosynthetic assimilation and stomatal conductance driven by changes in environmental parameters (CO2 , water availability, air humidity, temperature, nutrients). We review the mechanistic basis for a conceptual model, in light of recently published research, and discuss where isotopic observations do not match our current understanding of plant physiological response to the environment. We demonstrate that (1) the model was applied successfully in many, but not all studies; (2)although originally conceived for leaf isotopes, the model has been applied extensively to tree-ring isotopes in the context of tree physiology and dendrochronology. Where isotopic observations deviate from physiologically plausible conclusions, this mismatch between gas exchange and isotope response provides valuable insights into underlying physiological processes. Overall, we found that isotope responses can be grouped into situations of increasing resource limitation versus higher resource availability. The dual-isotope model helps to interpret plant responses to a multitude of environmental factors.

Persistence of Silver Nanoparticles Sorbed on Fresh-Cut Lettuce during Flume Washing and Centrifugal Drying

Increased agricultural use of silver nanoparticles (Ag NPs) may potentially lead to residual levels on fresh produce, raising food safety and public health concerns. However, the ability of typical washing practices to remove Ag NPs from fresh produce is poorly understood. This study investigated the removal of Ag NPs from Ag NP-contaminated lettuce during bench-top and pilot-scale washing and drying. Ag NP removal was first assessed by washing lettuce leaves in a 4-L carboy batch system using water containing chlorine (100 mg/L) or peroxyacetic acid (80 mg/L) with and without a 2.5% organic load and water alone as the control. Overall, these treatments removed only 3–7% of the sorbed Ag from the lettuce. Thereafter, Ag NP-contaminated lettuce leaves were flume-washed for 90 s in a pilot-scale processing line using ∼600 L of recirculating water with or without a chlorine-based sanitizer (100 mg/L) and then centrifugally dried. After processing, only 0.3–3% of the sorbed Ag was removed, probably due to the strong binding of Ag with plant organic materials. Centrifugation only removed a minor amount of Ag as compared to flume washing. However, the Ag concentration in the ∼750 mL of centrifugation water was much higher as compared to the flume water, suggesting that the centrifugation water would be preferred when assessing fresh-cut leafy greens for Ag contamination. These findings indicate that Ag NPs may persist on contaminated leafy greens with commercial flume washing systems unable to substantially reduce Ag NP levels.

Developmental performance of Eristalis tenax larvae (Diptera: Syrphidae): Influence of growth media and yeast addition during captive rearing

In holometabolous insects, life-history characteristics can vary in response to diet. The main aim of this contribution was to examine which diet best promotes larval development and survival of the aquatic saprophagous hoverfly Eristalis tenax L. (Diptera: Syrphidae). This study was motivated by a need to optimize techniques for rearing these insects in captivity. We studied how adding yeast to several rearing media based on animal droppings or decaying plant material affected development and survival in captive larvae, and whether these effects could be optimized depending on the amount of yeast and the rearing medium. In addition, premature exit of larvae was examined in two medium volumes to investigate differences in pupation. Larvae in yeast supplemented rabbit growth medium pupated and emerged faster than those in horse and antelope growth media. A high number of adult females emerged when compared to males, and both seemed to have a shorter developmental period in yeast supplemented growth media. Pupal survival was significantly greater in a mixture of droppings and plant organic matter, and a high medium volume of 140 ml (p < 0.05). Between 10% and 17% of larvae prematurely exited the aquatic medium in high (140) and low (70 ml) medium volumes, respectively. These results provide additional information that may be crucial for the successful mass rearing of E. tenax in captivity, and suggest that apart from the addition of yeast, growth medium quality and volume may be limiting factors for the production of large colonies of adults.

Beyond cannabinoids: Application of NMR-based metabolomics for the assessment of Cannabis sativa L. crop health.

While Cannabis sativa L. varieties have been traditionally characterized by their major cannabinoid profile, it is now well established that other plant metabolites can also have physiological effects, including minor cannabinoids, terpenes, and flavonoids. Given the multiple applications of cannabis in the medical field, it is therefore critical to characterize it according to its chemical composition (i.e., its metabolome) and not only its botanical traits. With this in mind, the cannabinoid and metabolomic profiles from inflorescences of two C. sativa varieties with either high Δ9-tetrahydrocannabinolic acid (THCA) or high cannabidiolic acid (CBDA) contents harvested at different times were studied. According to results from HPLC and NMR-based untargeted metabolomic analyses of organic and aqueous plant material extracts, we show that in addition to expected variations according to cannabinoid profiles, it is possible to distinguish between harvests of the same variety. In particular, it was possible to correlate variations in the metabolome with presence of powdery mildew, leading to the identification of molecular markers associated with this fungal infection in C. sativa.

Productivity of Water Meadows under Haymaking in the Mid-Stream of the Ob River

The productivity of water meadows was studied in the middle stream of the Ob River by direct in situ measurements of the live and dead components of phytomass/biomass, the features of the active layer in natural ecosystems, and the patterns of plant organic matter and productivity (NPP) in different plant communities, micro-landscapes, and underlying soils. The study was conducted across different ecosystems along two profiles in the floodplain: (i) in the conditions of haymaking and (ii) in all natural ecosystems. The study revealed drastic changes in floristic composition at two profiles (catenas) both in the structure of plant communities and in productivity/NPP at different levels of the floodplain. The maximum diversity of vegetation was found in pristine natural ecosystems. Haymaking leads to an increase in the part of perennial turf grasses and sedges and decrease in the part of motley grasses. The maximum stocks of above-ground biomass (1450 g/m2) and below-ground biomass (3380 g/m2) were found in topographic depressions dominated by sedges. Haymaking causes pressure on the formation of root systems in dry and wet (swampy) meadows, which in turn leads to a decrease in the below-ground component of plant biomass. The total stock of plant phytomass/biomass increases from the upper points to the lower points in the floodplain profile: from 2991 to 4565 g/m2 with haymaking and from 3370 to 4060 g/m2 across the natural ecosystems. The NPP decreases by 12% in the upper and by 5% in the middle parts of the catena under haymaking, but it does not change in the lower part of catena as compared to all natural ecosystems.

Effect of growth regulators and organic matter on the growth of Sappan wood seedlings (Caesalpinia sappan L.)

Sappan wood is a useful woody plant from Brazil that could possibly be utilized as a natural dye. The generative proliferation of Sappan wood is hindered by its sluggish seed germination (dormancy), which necessitates greater efforts to break seed dormancy through the use of plant growth regulator (PGR) and organic matter as a planting media mixture to improve seedling growth. This study was conducted during dry season from June to September 2022 at experimental field of Faculty of Agriculture, Universitas Padjadjaran_with an aim to determine the effect of PGR (IAA, NAA, BAP) and organic matter (cow manure) on the growth of Sappan wood seeds. The design used was a randomized block design (RBD) with 14 combination treatments of different types of PGR with the concentration of 1.25 ppm and the use of organic matter that is cow manure (comparison 2:1) with three replications. The data obtained were then processed using one-way ANOVA and continued with the Duncan Multiple Range Test (DMRT) at a 95% confidence level. The use of plant growth regulators (auxin and cytokinin) and organic matter affected the growth of Sappan wood seedlings, especially on the variables of seedling height (22.37 cm), stem diameter (3.89 mm), number of leaves (8.67), leaf area (104.84 cm2), root length (26.03 cm), dry weight of roots (1.15 g) and dry weight of the stem (1.6 g), but it was not significantly affected by the root volume. The combination of IAA+BAP 1.25 ppm and organic matter in the form of cow manure (2 : 1) was selected as the best treatment to increase the growth of Sappan wood seedlings.

Investigation of changes in the iodine concentrations of oceanic sediment and terrestrial soil samples after thermal drying.

To certify the suitability of pretreatment by thermal drying to measure iodine concentrations of oceanic sediment and terrestrial soil samples, changes in iodine concentrations after drying (50, 80 or 85, and 110°C for 48h) were examined using the samples in addition to a terrestrial plant (pine needles), which was selected as an intact organic sample. The iodine concentrations per wet weight of the sediment and soil samples processed by thermal drying were comparable to those of the raw samples at all temperatures. However, the concentrations of the plant samples dried at 85 and 110°C were lower than those of the raw samples. The lower concentrations of the plant samples at higher temperatures were considered to be derived from the volatilization of a part of the plant's organic matter. Finally, these results suggested that the iodine concentrations in oceanic sediment and terrestrial soil samples scarcely change after thermal drying at 110°C, although the concentrations may decrease when these samples include high contributions of fresh organic matter.

Sugar infusion into trees: A novel method to study tree carbon relations and its regulations.

Many carbon-related physiological questions in plants such as carbon (C) limitation or starvation have not yet been resolved thoroughly due to the lack of suitable experimental methodology. As a first step towards resolving these problems, we conducted infusion experiments with bonsai trees (Ficus microcarpa) and young maple trees (Acer pseudoplatanus) in greenhouse, and with adult Scots pine trees (Pinus sylvestris) in the field, that were "fed" with 13C-labelled glucose either through the phloem or the xylem. We then traced the 13C-signal in plant organic matter and respiration to test whether trees can take up and metabolize exogenous sugars infused. Ten weeks after infusion started, xylem but not phloem infusion significantly increased the δ13C values in both aboveground and belowground tissues of the bonsai trees in the greenhouse, whereas xylem infusion significantly increased xylem δ13C values and phloem infusion significantly increased phloem δ13C values of the adult pines in the field experiment, compared to the corresponding controls. The respiration measurement experiment with young maple trees showed significantly increased δ13C-values in shoot respired CO2 at the time of four weeks after xylem infusion started. Our results clearly indicate that trees do translocate and metabolize exogenous sugars infused, and because the phloem layer is too thin, and thus xylem infusion can be better operated than phloem infusion. This tree infusion method developed here opens up new avenues and has great potential to be used for research on the whole plant C balance and its regulation in response to environmental factors and extreme stress conditions.

The dispersal of fluvially discharged and marine, shelf-produced particulate organic matter in the northern Gulf of Mexico

Abstract. Rivers play a key role in the global carbon cycle by transporting terrestrial organic matter (TerrOM) from land to the ocean. Upon burial in marine sediments, this TerrOM may be a significant long-term carbon sink, depending on its composition and properties. However, much remains unknown about the dispersal of different types of TerrOM in the marine realm upon fluvial discharge since the commonly used bulk organic matter (OM) parameters do not reach the required level of source- and process-specific information. Here, we analyzed bulk OM properties, lipid biomarkers (long-chain n-alkanes, sterols, long-chain diols, alkenones, branched and isoprenoid glycerol dialkyl glycerol tetraethers (brGDGTs and isoGDGTs)), pollen, and dinoflagellate cysts in marine surface sediments along two transects offshore the Mississippi–Atchafalaya River (MAR) system, as well as one along the 20 m isobath in the direction of the river plume. We use these biomarkers and palynological proxies to identify the dispersal patterns of soil–microbial organic matter (SMOM), fluvial, higher plant, and marine-produced OM in the coastal sediments of the northern Gulf of Mexico (GoM). The Branched and Isoprenoid Tetraether (BIT) index and the relative abundance of C32 1,15-diols indicative for freshwater production show high contributions of SMOM and fluvial OM near the Mississippi River (MR) mouth (BIT = 0.6, FC321,15 &gt; 50 %), which rapidly decrease further away from the river mouth (BIT &lt; 0.1, FC321,15 &lt; 20 %). In contrast, concentrations of long-chain n-alkanes and pollen grains do not show this stark decrease along the path of transport, and especially n-alkanes are also found in sediments in deeper waters. Proxy indicators show that marine productivity is highest close to shore and reveal that marine producers (diatoms, dinoflagellates, coccolithophores) have different spatial distributions, indicating their preferred niches. Close to the coast, where food supply is high and waters are turbid, cysts of heterotrophic dinoflagellates dominate the assemblages. The dominance of heterotrophic taxa in shelf waters in combination with the rapid decrease in the relative contribution of TerrOM towards the deeper ocean suggest that TerrOM input may trigger a priming effect that results in its rapid decomposition upon discharge. In the open ocean far away from the river plume, autotrophic dinoflagellates dominate the assemblages, indicating more oligotrophic conditions. Our combined lipid biomarker and palynology approach reveals that different types of TerrOM have distinct dispersal patterns, suggesting that the initial composition of this particulate OM influences the burial efficiency of TerrOM on the continental margin.

Geochemical characteristics and significance of aromatic hydrocarbons in crude oil from the East Fukang Sag, Junggar Basin, NW China

The aromatic compounds of twenty crude oil samples from different formations in the East Fukang Sag were studied by the gas chromatography–mass spectrometry technique. Through analysis of the composition of the main aromatic hydrocarbons, the studied crude oil samples were generally divided into two types: Oil type I had the relatively high content of the naphthalene series, biphenyl series and dibenzofuran series, while the samples from Oil type II contained relatively high abundance of phenanthrene series, fluorene series, triaromatic steroid series, and obvious methyltrimethyltridecylchromans. The geochemical parameters reflecting the source and sedimentary environment in naphthalene series, phenanthrene series, biphenyl series, three-fluorene series, and triaromatic steroid series were systematically analyzed. Analysis of the results showed that studied oil samples from the East Fukang Sag were of continental origin and deposited in a weakly oxidizing to weakly reducing environment with fresh-brackish water. Oil type I was characterized by considerably abundant terrestrial higher plant organic matter inputs, while Oil type II was typical with obviously lower aquatic organisms. Maturity-related parameters calculated from alkyl naphthalenes, alkyl phenanthrenes, alkyl dibenzothiophenes, and methyltrimethyltridecylchromans showed that all the studied oil samples have reached the mature stage.

Incorporation of tritium by pepper and eggplant cultures with short-term exposure to tritium oxide

Incorporation of tritium by pepper and eggplant cultures with short-term exposure to tritium oxide

Prediction Models Based on Soil Characteristics for Evaluation of the Accumulation Capacity of Nine Metals by Forage Sorghum Grown in Agricultural Soils Treated with Varying Amounts of Poultry Manure.

Predictive models were generated to evaluate the degree to which nine metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) were absorbed by the leaves, stems and roots of forage sorghum in growing media comprising soil admixed with poultry manure concentrations of 0, 10, 20, 30 and 40g/kg. The data revealed that the greatest contents of the majority of the metals were evident in the roots rather than in the stems and leaves. A bioaccumulation factor (BAF) < 1 was calculated for Cr, Fe, Ni, Pb and Zn; BAF values for Co, Cu, Mn and Cd were 3.99, 2.33, 1.44 and 1.40, respectively, i.e., > 1. Translocation factor values were < 1 for all metals with the exception of Co, Cr and Ni, which displayed values of 1.20, 1.67 and 1.35 for the leaves, and 1.12, 1.23 and 1.24, respectively, for the stems. The soil pH had a negative association with metal tissues in plant parts. A positive relationship was observed with respect to plant metal contents, electrical conductivity and organic matter quantity. The designed models exhibited a high standard of data precision; any variations between the predicted and experimentally observed contents for the nine metals in the three plant tissue components were nonsignificant. Thus, it was concluded that the presented predictive models constitute a pragmatic tool to establish the safety from risk to human well-being with respect to growing forage sorghum when cultivating media fortified with poultry manure.