Primary Organic Matter Research Articles

Hydroureter

Hydroureter

Benthic Foraminiferal Response to the Millennial-Scale Variations in Monsoon-Driven Productivity and Deep-Water Oxygenation in the Western Bay of Bengal During the Last 45 ka

In this study, we presented a high-resolution benthic foraminiferal assemblage record from the western Bay of Bengal (BoB) (off Krishna–Godavari Basin) showing millennial-scale variations during the last 45 ka. We studied temporal variations in benthic foraminiferal assemblages (relative abundances of ecologically sensitive groups/species, microhabitat categories, and morphogroups) to infer past changes in sea bottom environment and to understand how monsoon induced primary productivity-driven organic matter export flux and externally sourced deep-water masses impacted the deep-sea environment at the core site. Our records reveal a strong coupling between surface productivity and benthic environment on glacial/interglacial and millennial scale in concert with Northern Hemisphere climate events. Faunal data suggest a relatively oxic environment when the organic matter flux to the sea floor was low due to low primary production during intensified summer monsoon attributing surface water stratification and less nutrient availability in the mixed layer. Furthermore, records of oxygen-sensitive benthic taxa (low-oxygen vs. high-oxygen benthics) indicate that changes in deep-water circulation combined with the primary productivity-driven organic matter flux modulated the sea bottom oxygen condition over the last 45 ka. We suggest that the bottom water at the core site was well-ventilated during the Holocene (except for the period since 3 ka) compared with the late glacial period. At the millennial timescale, our faunal proxy records suggest relatively oxygen-poor condition at the sea floor during the intervals corresponding to the cold stadials and North Atlantic Heinrich events (H1, H2, H3, and H4) compared with the Dansgaard/Oeschger (D-O) warm interstadials. The study further reveals oxygen-poor bottom waters during the last glacial maximum (LGM, 19–22 ka) which is more pronounced during 21–22 ka. A major shift in sea bottom condition from an oxygenated bottom water during the warm Bølling–Allerød (B/A) (between 13 and 15 ka) to the oxygen-depleted condition during the cold Younger Dryas (YD) period (between 10.5 and 13 ka) is noticed. It is likely that the enhanced inflow of North Atlantic Deep Water (NADW) to BoB would have ventilated bottom waters at the core site during the Holocene, B/A event, and probably during the D-O interstadials of marine isotope stage (MIS) 3.

Acute ambient air pollution exposure and placental Doppler results in the NICHD fetal growth studies – Singleton cohort

BackgroundIncreased placental vascular resistance is a proposed mechanism by which air pollution exposure during pregnancy lowers birth weight and increases pregnancy-induced hypertensive disorders. ObjectiveTo examine the impact of acute air pollution exposure during pregnancy on uterine and umbilical artery Doppler indicators of placental vascular resistance. MethodsAfter a first ultrasound to confirm gestational age, 2562 pregnant women recruited in 12 clinics throughout the United States underwent up to five standardized ultrasounds with Doppler measurements. Exposures to 11 air pollutants were estimated for the hour of ultrasound and each of the 2 h prior to ultrasound at the clinics using the National Air Quality Forecast Capability reanalysis products. We used mixed logistic regression to study the longitudinal odds ratio (OR) of any, uni- or bi-lateral systolic and diastolic uterine artery notching compared to no notching and the longitudinal OR of abnormal end diastolic flow of the umbilical artery compared to forward flow. Uterine and umbilical artery resistance indexes were studied using linear mixed models. ResultsEach inter-quartile range (IQR) increase of particulate matter < 2.5 μm, nitrate, ammonium, primary organic matter (POM) and nitrogen dioxide during the hour of ultrasound was associated with a decreased risk of unilateral systolic notch and with increased resistance index of the left uterine artery. For the umbilical artery, each IQR increase in ozone was associated with decreased resistance index (b: −0.26, 95 % CI: −0.52, −0.01) and with a decreased risk of abnormal end diastolic flow (OR: 0.36, 95 % CI: 0.14, 0.94); while each IQR increase of elemental carbon and POM was associated with increased risk of abnormal end diastolic flow (OR: 1.47, 95 % CI: 1.02, 2.13 and OR: 1.67, 95 % CI: 1.17, 2.39, respectively). DiscussionOur results suggest acute air pollution exposure may influence placental vascular resistance.

THE ALGOFLORA OF THE PONDS OF DIUKOVSKYI PARK OF CITY ODESA

Introduction. Microscopic algae play an important role in ecosystems of ponds. They create a primary organic matter, select oxygen, utilize carbon dioxide, inorganic and organic contamination in water and are a meal for numerous aquatic lives (infusoria, worms, crustaceas and fishes). Aim. The aim of the work was to study the current state of the algoflora of the ponds studied. Methods. The samples collected from November 2011 for August in 2020 on two ponds of Diukovskyi Park served as materials for the research. The samples were collected in phytoplankton, periphyton and microphytobenthos in spring, in summer and in autumn. On the whole 80 samples were collected and treated. The specific composition of algae was studied by the light microscope XSP-104. Results. The results of the research (2011-2020) of the specific composition of microscopic algae from 2 ponds of Diukovskyi Park of city Odesa were generalised. The species composition of the microphytes of Dukovskyi ponds included 67 species of algae, which belonged to 49 genera, 36 families, 21 orders, 9 classes, 7 divisions, 4 kingdoms and 2 empires. The number of species in the ponds was dominated by representatives of diatoms (38 species), blue-green (13), green (7) and khar (5). 13 species belonged to the empire of prokaryotes, 54 species – to eukaryotes. The kingdom of eubacteria is represented by 13, chromists ‒ 40, protozoa – 2, plants ‒ 12 species. Representatives of the leading genera Cosmarium Corda et Ralfs (5 species), Nitzschia Hassall (4) make up the algoflora of the ponds. For the first time, 14 new species of algae were registered for the ponds of Diukovskyi Park. The Sorensen-Chekanov similarity coefficient of the species composition of the algae ponds between the algoflores of Diukovskyi park and the arboretum named After Victory was 0.44, and Jakkar similarity ratio between them ‒ 0.29. In phytoplankton of ponds 20, periphyton ‒ 23 and microphytobentos ‒ 24 species were identified. By type of organization, single-celled forms were represented by 25, colonial - 33 and multicellular ‒ 6 species. Among them, there were 40 immobile, 27 taxa ‒ mobile. In accordance with the type of morphological differentiation of tallomas coccoid forms (50 taxa) dominated, filamentous constituted 6, capsal ‒ 6 and monad ‒ 4 species. The algoflora of the ponds of Diukovskyi Park is freshwater, alkaliphilic, mesosaprobic and cosmopolitan. Conclusions. The algoflora of two ponds of Diukovskyi Park consists of 67 species of microscopic algae, which belong to 7 divisions, 4 kingdoms and 2 empires. For the first time14 new species were identified for the ponds. The algoflora of ponds of Diukovskyi Park is freshwater, alkaliphilic, mesosaprobic and cosmopolitan.

The influence of fire aerosols on surface climate and gross primary production in the Energy Exascale Earth System Model (E3SM)

AbstractFire-emitted aerosols play an important role in influencing Earth’s climate, directly by scattering and absorbing radiation and indirectly by influencing cloud microphysics. The quantification of fire-aerosol interactions, however, remains challenging and subject to uncertainties in emissions, plume parameterizations, and aerosol properties. Here we optimized fire-associated aerosol emissions in the Energy Exascale Earth System Model (E3SM) using the Global Fire Emissions Database (GFED) and AERONET aerosol optical depth (AOD) observations during 1997-2016. We distributed fire emissions vertically using smoke plume heights from Multi-angle Imaging SpectroRadiometer (MISR) satellite observations. From the optimization, we estimate that global fires emit 45.5 Tg y-1 of primary particulate organic matter and 3.9 Tg y-1 of black carbon. We then performed two climate simulations with and without the optimized fire emissions. We find that fire aerosols significantly increase global AOD by 14 ± 7% and contribute to a reduction in net shortwave radiation at the surface (-2.3 ± 0.5 W m-2). Together, fire-induced direct and indirect aerosol effects cause annual mean global land surface air temperature to decrease by 0.17 ± 0.15°C, relative humidity to increase by 0.4 ± 0.3%, and diffuse light fraction to increase by 0.5 ± 0.3%. In response, GPP declines by 2.8 Pg C y-1, as a result of large positive drivers (decreases in temperature and increases in humidity and diffuse light) nearly cancelling out large negative drivers (decreases shortwave radiation and soil moisture). Our analysis highlights the importance of fire aerosols in modifying surface climate and photosynthesis across the tropics.

High-pressure balloon dilatation for the treatment of primary obstructive megaureter: is it the first line of treatment in children and infants?

To evaluate the efficacy of high-pressure balloon dilatation (HPBD) as treatment of primary obstructive megaureter (POM) in paediatric patients, we analysed the data of our institute from June 2018 to September 2019. 14 patients, aged 5 months to 5 years, with POM were treated with HPBD. All patients had a distal ureter dilatation greater than 7 mm associated with obstructive features on a mercaptoacetyl triglycine-3 diuretic renogram scan, and a voiding cystourethrogram without vesicoureteral reflux. HPBD was performed in 12 patients, whereas 2 patients (14%), aged 5 and 6 months, required open surgical treatment because of failure to pass the balloon catheter through the vesicoureteral junction. The procedure was performed with a 5 Fr balloon catheter for two cycles of 5 minutes each at 17 atm. A double-J stent and a urinary catheter were inserted at the end of procedure in all patients. No operative complications or symptoms or recurrence were recorded in our series. The patients were generally discharged 24 hours after surgery. All the patients showed an improvement on ultrasonography at the postoperative follow-up, with no evidence of obstruction. During the procedure a clear stenotic ring was identified in 10 of the 12 patients, which disappeared in all 10 cases after the HPBD technique. Based on our experience, HPBD may be considered the first-line surgical approach in the treatment of POM in children, avoiding bladder surgery in most cases.

P1089 - Telocytes and Cajal cells deficiency in the distal ureteric segment of pediatric patients with congenital Primary Obstructed Megaureter (POM) causing massive ureterohydronephrosis is an indication for early surgery

P1089 - Telocytes and Cajal cells deficiency in the distal ureteric segment of pediatric patients with congenital Primary Obstructed Megaureter (POM) causing massive ureterohydronephrosis is an indication for early surgery

Soil structure as a significant indirect factor affecting crop yields

Soil structure as a significant indirect factor affecting crop yields

Macroalgae degradation promotes microbial iron reduction via electron shuttling in coastal Antarctic sediments.

Colonization of newly ice-free areas by marine benthic organisms intensifies burial of macroalgae detritus in Potter Cove coastal surface sediments (Western Antarctic Peninsula). Thus, fresh and labile macroalgal detritus serves as primary organic matter (OM) source for microbial degradation. Here, we investigated the effects on post-depositional microbial iron reduction in Potter Cove using sediment incubations amended with pulverized macroalgal detritus as OM source, acetate as primary product of OM degradation and lepidocrocite as reactive iron oxide to mimic in situ conditions. Humic substances analogue anthraquinone-2,6-disulfonic acid (AQDS) was also added to some treatments to simulate potential for electron shuttling. Microbial iron reduction was promoted by macroalgae and further enhanced by up to 30-folds with AQDS. Notably, while acetate amendment alone did not stimulate iron reduction, adding macroalgae alone did. Acetate, formate, lactate, butyrate and propionate were detected as fermentation products from macroalgae degradation. By combining 16S rRNA gene sequencing and RNA stable isotope probing, we reconstructed the potential microbial food chain from macroalgae degraders to iron reducers. Psychromonas, Marinifilum, Moritella, and Colwellia were detected as potential fermenters of macroalgae and fermentation products such as lactate. Members of class deltaproteobacteria including Sva1033, Desulfuromonas, and Desulfuromusa together with Arcobacter (former phylum Epsilonbacteraeota, now Campylobacterota) acted as dissimilatory iron reducers. Our findings demonstrate that increasing burial of macroalgal detritus in an Antarctic fjord affected by glacier retreat intensifies early diagenetic processes such as iron reduction. Under scenarios of global warming, the active microbial populations identified above will expand their environmental function, facilitate OM remineralisation, and contribute to an increased release of iron and CO2 from sediments. Such indirect consequences of glacial retreat are often overlooked but might, on a regional scale, be relevant for the assessment of future nutrient and carbon fluxes.

Preservation and Distributions of Covalently Bound Polyaromatic Hydrocarbons in Ancient Biogenic Kerogens and Insoluble Organic Macromolecules.

The likelihood of finding pristine molecular biosignatures preserved in Earth's oldest rocks or on other planetary bodies is low, and new approaches are needed to assess the origins of highly altered and recalcitrant organic matter. In this study, we aim to understand the distributions and systematics of preservation of ancient polycyclic aromatic hydrocarbons (PAHs), as both free hydrocarbons and bound within insoluble macromolecules. We report the distributions of bound PAHs generated by catalytic hydropyrolysis from ancient biogenic kerogens and from insoluble organic matter (IOM) in high-temperature carbonaceous residues from pyrobitumens and synthetic coke. For biogenic kerogens, the degree of thermal maturity exerts the primary control on the preservation and distributions of the major five-ring and six-ring PAH compounds. This holds for both Precambrian and Phanerozoic rocks, thus source variation in primary biogenic organic matter inputs does not exert the major control on bound PAH. The IOM samples, predominantly residues from hydrocarbon cracking at high temperatures, preserve a bound PAH profile significantly distinct from ancient biogenic kerogens and characterized by an absence of perylene and higher abundance of large-ring condensed PAHs. Covalently bound PAH profiles offer promise as "last resort" molecular biosignatures for aiding the astrobiological search for ancient life.

Pore formation and evolution of organic-rich shale during the entire hydrocarbon generation process: Examination of artificially and naturally matured samples

Shale pore type and variation have significant influences on natural gas storage and are of vital importance for shale gas resource evaluation. To better understand the formation and evolution of shale pores during hydrocarbon generation process, organic geochemistry, X-ray diffraction, field emission scanning electron microscopy (FE-SEM), and low-pressure nitrogen gas adsorption (N2GA) were applied to samples created by thermal simulation and to naturally evolved samples of the Upper Permian Dalong Formation in the northwestern Sichuan Basin. The results show that the development of organic matter (OM) pores is controlled by kerogen type and thermal maturation level and begins at equivalent vitrinite reflectance (eqvRo) value of 0.91%. Two types of OM pores are developed during OM evolution stage, as bubble pores that are formed at the oil window stage and spongy pores which occcur at the dry gas stage. Maximum pore volume, particularly mesopore volume, occurs within two opportune development periods with the corresponding eqvRo values of 1.11–1.53% and 2.5–2.9%, respectively. The periods are known to be the two peak stages of shale pore development. The first peak corresponds to the late oil generation stage, and the second corresponds to the cracking peak of extractable OM to gas, during which numerous OM micropores and mesopores are generated. OM pore generation is generally resulted from OM decomposition, and pore structure parameters exhibit significant positive correlations with OM reduction for simulated samples. For naturally matured samples, TOC content is positively correlated with pore structures. Extractable OM generated from primary kerogen fills OM pores and mineral-related pores and further reduces shale pore volume. In terms of analysis on naturally matured samples with similar maturities, OM pores in type II1 kerogen are inferior to those in type I kerogen but more developed than those in type III kerogen. Shale pore evolution is also controlled by diagenesis. Compaction and cementation have adverse effects on shale pore preservation during early and late diagenesis stages, which leads to a significant decrease in shale pore volume, particularly that of mesopores. It should be noted that OM pores are better developed and preserved even when the eqvRo value exceeds 3.25%, which is of vital importance for extending the field of shale gas exploration of over-mature shale reservoirs.

Isotopic niche differentiation in benthic consumers from shallow-water hydrothermal vents and nearby non-vent rocky reefs in northeastern Taiwan

Shallow-water hydrothermal vents (SVs) off Kueishan (KS) Islet are located along the northeastern coast of Taiwan. Although the trophic relationships of the sublittoral (15–30 m) and upper bathyal (200–300 m) vents in this region have been investigated, a comparison of SVs and adjacent non-vent ecosystems has not been undertaken. We compared the trophic structure and isotopic niche width of consumers in benthic communities around SVs off KS Islet with nearby non-vent rocky reefs (NV) to address this gap. The trophic structures for both SV and NV habitats were categorized into four trophic levels based on δ13C and δ15N signatures. SV sites ranged from −27.7 to −14.3‰ (δ13C) and from −7.3 to 12.2‰ (δ15N), whereas NV sites ranged from −20.2 to −13.1‰ (δ13C) and from 2.2 to 11.9‰ (δ15N). We found a notable difference in δ13C and δ15N values for primary producers and sediment organic matter between the two habitats indicating that available nutrient sources were different and more diversified in SV than those in NV. Based on the types of consumer feeding guilds, no difference in niche width of filter feeders between SV and NV was detected by ellipses analysis. Besides, a narrower niche width for scavengers in SV and differentiated niche positions for carnivores in both habitats were found. We conclude that plankton-derived production (i.e., dead zooplankton killed by sulfurous plumes) plays a significant role in providing food to benthic communities. These include not only scavengers, such as vent crabs, but also carnivores in SVs off KS Islet where extreme values of pH (1.52), temperature (116 °C), and H2S (172 mmol/mol) are known to occur.

Telocytes, c-Kit positive cells, Smooth muscles, and collagen in the ureter of pediatric patients with congenital primary obstructive megaureter: elucidation of etiopathology

ABSTRACT Congenital primary obstructive megaureter (POM) is an uncommon pediatric anomaly that is due to obstructive distal ureter leading to the loss of peristalsis with consequent ureterohydronephrosis causing loss of kidney function. The objectives are to elucidate the etiology of POM by demonstrating the presence of interstitial cells of Cajal (ICC), telocytes, smooth muscles, and collage in the obstructive and dilated ureteral segments. The study was carried out on 15 surgical specimens of congenital POM in pediatric patients, age range was 4 to 24 months, they were operated upon by excision of the obstructed segment, tailoring the dilated ureter, and anastomosing it to the bladder. Specimens included the obstructed ureteral segment and part of the dilated ureter. Specimens were examined with hematoxylin and eosin (H&E) stain, Modified Gomori trichrome stain, immunohistochemistry (IHC) with α-muscle actin, and c-kit (CD117), and transmission electron microscopy (TEM). Obstructed segment showed excess collagen intervening between smooth muscles, excess c-Kit positive cells, and presence of telocytes. The dilated segment of the ureteral wall is formed of smooth muscle bundles with scanty collagen. Staining with c-Kit did not demonstrate positive cells. TEM showed myofibroblasts and close adherence of smooth muscle cells to each other with absence of telocytes. The pathophysiology of POM is multifactorial. Loss of interstitial cells and rarity of collagen result in loss of elasticity of dilated segment leading to massive dilatation. While the obstructed segment had no muscle conductivity due to excess collagen irrespective of presence of telocytes.

Organic geochemical characteristics and gas prospectivity of Permian source rocks in western margin of Songliao Basin, northeastern China

The Permian in western margin of Songliao Basin is a strategic potential field of oil and gas resources in northeastern China, but the systematic researches since few boreholes were drilled up to Permian strata, as well as there is a lack of seismic and well-logging data. This paper presents the lithological composition of the Permian Formations on the basis of regional geological survey in western margin of Songliao Basin. A total of 60 mudstones and shales were collected to evaluate the organic geochemical and petrophysical characteristics and gas prospectivity of Permian source rocks. The Permian is composed of Shoushangou, Dashizai, Zhesi and Linxi Formation, which represent large sets of mudstones and shales, which are mainly deposited in a weakly to strongly reducing marine environment. The primary organic matter precursors in Permian were lower aquatic organisms such as zooplankton and algae, while a few samples of Linxi Formation indicate mixed sources of lower aquatic organisms and terrigenous higher plants. The Permian gas–prone source rocks are at over–mature stage with vitrinite reflectance Ro% = 2.01%–3.14% and mainly classified as fair to good quality and type II–III kerogens, and generally have a tricyclic terpane distribution pattern of C21>C23>C20, but Shoushangou Formation and Linxi Formation have subordinate patterns of C21>C20>C23 and C23>C21>C20, respectively. The residual organic matters in Permian source rocks have CH4 yields up to 24.34 mg/g∙TOC at EASY%Ro = 4.45%, which indicate the possibility of secondary gas generation at Ro% = 2.0%–3.5%. The pores and fractures are developed in Permian source rocks with widths of 5.28–18.64 μm, and mean values of porosity and permeability are 2.17% and 0.0043 × 10−3 μm2, respectively. The source–reservoir–cap rock assemblages in Carboniferous–Permian and Mesozoic sedimentary sequences are included in situ and near–source accumulation in Permian, and long–distance migration and accumulation in underlying Carboniferous and overlying Triassic, Jurassic and Cretaceous. The Permian system can be regarded as a potential gas exploration target in the western margin of Songliao Basin.

A case of Undetected Congenital Primary Obstructed Megaureter (POM)

Primary obstructed Megaureter (POM) defined as dilatation of ureter bigger than the normal size with or without renal pelvis dilatation. POM was first described in 1923 by Clark [1]. This is the second most common aetiology causing hydronephrosis in infant and it more prevalence in boys compared with girls. Early detection of POM is important to guide us in the long management of the patient and better outcome. Surgical intervention still mainstay treatment for POM in failure of conservative management.

Chemical Characteristics and Sources of Water-Soluble Organic Nitrogen Species in PM2.5 in Nanjing, China

Water-soluble organic nitrogen (WSON) is an important component of PM2.5 which may affect air quality, climate and human health. Herein, one-year field samples of atmospheric PM2.5 (June 2017–May 2018) were collected in northern Nanjing. Chemical characterization of PM2.5 major components as well as WSON were conducted, and WSON composition and sources were further investigated via measurements by a Aerodyne soot particle aerosol mass spectrometer (SP-AMS) as well as positive matrix factorization (PMF). Inorganic ions, mainly consisting of ammonium, sulfate, and nitrate, were found to dominate PM2.5 mass (58.7%), followed by organic matter (OM) (22.6%), and elemental carbon (EC) (2.1%). Water-soluble OM dominated OM (65.1%), and its temporal variation was closely correlated with that of secondary organic matter, while time series of water-insoluble OM concentrations correlated tightly with that of primary organic matter. Average WSON concentration was 2.15 μg/m3, which was highest in winter and lowest in summer. Correlation analysis of WSON with PM2.5 components also indicated that WSON was mainly from secondary sources. SP-AMS revealed that WSON mass spectrum was composed of CxHyNp+ (91.2%) and CxHyOzNp+ (8.8%), indicating dominance of amines and other oxygenated ON compounds. PMF analysis resolved two primary sources (traffic, biomass burning) and two secondary sources (less-oxidized and more-oxidized factors) of WSOM and WSON, and the secondary source dominated both WSOM and WSON. Contribution of the more-oxidized ON factor was very high in winter, and the less-oxidized factor was significant in summer, indicating a likely important role of aqueous-phase processing in winter as well as photochemical oxidation in summer to WSON.

Phytoplankton biomass, dissolved organic matter, and temperature drive respiration in whole lake nutrient additions

AbstractLake respiration is supported by a mixture of autochthonous and allochthonous resources, but the relative significance and interaction of these sources are uncertain across gradients of primary production and organic matter inputs. We manipulated autochthonous resources by adding inorganic nitrogen and phosphorus to two lakes during three summers and monitored a third reference lake. Allochthonous resources were measured as fluorescent dissolved organic matter (FDOM). In the reference and two experimental lakes, daily estimates of respiration were made from continuously deployed oxygen sensors. Daily mean values of temperature and FDOM were determined from high‐frequency measurements along with daily measures of chlorophyll a, an index of phytoplankton biomass. We analyzed time series of respiration and tested models that used combinations of the independent variables chlorophyll, FDOM, and temperature. The best models included all three of the independent variables. Respiration increased twofold over the temperature range of 14.5–28.6°C. Respiration increased in association with phytoplankton blooms caused by the nutrient additions, but did not track blooms closely, because of large day‐to‐day variability. Respiration varied positively with FDOM that was primarily allochthonous and differed among lakes and years. We did not detect an interaction between chlorophyll and FDOM despite the large number of observations and range of chlorophyll and FDOM. Hydrologic, climatic, and land use changes are altering temperature and inputs of nutrients and organic matter to lakes. Our results indicate that these changes may lead to linear responses in ecosystem processes like respiration for the wide range of inputs represented in this study.

Quantitative palaeobathymetric reconstructions based on foraminiferal proxies: a case study from the Neogene of south‐west Spain

AbstractQuantitative palaeobathymetric reconstructions based on foraminiferal proxies have been used in a wide variety of geological studies on tectonic, climatic and environmental changes in sedimentary basins. However, palaeo‐water‐depth estimates are frequently biased due to taphonomic processes (dissolution, transport) as well as local conditions (primary productivity, oxygen content, and organic matter fluxes). This study evaluated the level of reliability of three commonly used transfer equations based on planktic and benthic foraminiferal proxies that produce different palaeobathymetric results, using Neogene sediments from the Guadalquivir Basin, south‐west Spain. The most trustworthy method involves removing abundant infaunal benthic foraminifera before applying the palaeo‐water‐depth equation based on benthic foraminiferal water‐depth ranges and presence/absence of species. This new approach provides sound palaeobathymetric results that improve estimations of long and short‐term relative sea‐level changes with negligible influence of taphonomic as well as ecological factors. When using one equation based on planktic/benthic ratios (P/B ratios), removing all infaunal benthic foraminiferal species improves the accuracy of P/B ratios, which yields more accurate palaeodepth reconstructions despite the low level of trustworthiness of this equation for both long and short‐term relative sea‐level variations.

Trans‐Regional Transport of Haze Particles From the North China Plain to Yangtze River Delta During Winter

AbstractAccording to atmospheric modeling and satellite observations, cold fronts can cause trans‐regional transport (TRT) of haze particles from the North China Plain (NCP) to Yangtze River Delta (YRD) in winter. However, compositions and aging of haze aerosols during the TRT have not been studied. We showed the TRT PM2.5 dominated by organic matter (OM) (30%) and secondary inorganic ions (36%) in the NCP and 29% and 60% in the YRD. Following the TRT, abundant spherical primary OM particles (i.e., tarballs) (71% by number) mainly from residential coal burning in rural areas of the NCP unexpectedly occurred in the YRD. The inert tarballs display similar sizes (∼300 nm) and O/C ratios (∼0.15), but the mixture of nitrate, sulfate, and secondary OM as the coatings completely convert the hydrophobic tarballs into hydrophilic ones in the TRT. The aging and transport of tarballs from the NCP to YRD further indicate that the TRT not only brought various trace gases (e.g., CO, SO2, NOx, and VOCs) but also carried large numbers of nanosized primary particles (e.g., tarball, metal, fly ash, and soot) with secondary coatings over 1,000 km. The findings suggest that these many nanosized tarballs containing brown carbon and highly toxic species in the NCP influence regional climate and human health in northern and eastern China, which needs more attention. Although the NCP and YRD have different energy consumption structures in winter and are two isolated administrative regions, we emphasize the need for a coordinated cross‐regional emission reduction strategy for TRT haze control.

Carbon Dioxide and Methane Fluxes from Various Vegetation Communities of a Natural Tropical Freshwater Wetland in Different Seasons

Emission of carbon dioxide (CO2) and methane (CH4) is of interest in tropical wetland studies because the high and relatively stable temperatures year-round enhance both primary productivity and organic matter decomposition. Nonetheless, there is scarcity of data on emission of these carbon-based greenhouse gases from tropical wetlands. We investigated CO2 and CH4 fluxes from a natural tropical freshwater wetland in Uganda under different dominant vegetation communities, i.e., Cyperus papyrus (Papyrus), Typha latifolia (Typha) and Phragmites mauritianus (Phragmites), during the dry and wet seasons. Gas samples were collected using static chambers and analyzed by gas chromatography. Fluxes (mg C m−2 h−1) of both CO2 and CH4 from Papyrus (732.9 ± 48.7 [mean ± standard error] and 14.1 ± 0.8, respectively) and from Typha (759.7 ± 51.4 and 13.5 ± 1.2, respectively) insignificantly varied (p > 0.05) during the dry season. However, CO2 and CH4 fluxes from both vegetation communities during this season were significantly lower and higher (p 0.05) occurred among the three vegetation communities for both CO2 and CH4 fluxes (Phragmites: 691.9 ± 55.8 and 15.6 ± 1.1, Typha: 682.0 ± 53.3 and 16.3 ± 1.2, and Papyrus: 651.2 ± 49.0 and 17.1 ± 1.7, respectively). Water level was the main driver of CO2 and CH4 fluxes from the wetland, suggesting its importance in any efforts to regulate fluxes of both gases in tropical wetlands. We estimated total annual CO2 and CH4 emissions from Uganda’s wetland soils in the ranges of 159.5 × 106–180.2 × 106 t C (tonnes of carbon) and 278.9 × 104–359.7 × 104 t C, respectively. • Vegetation community does not influence CO2 and CH4 fluxes from a tropical freshwater wetland soil under continuous flooding • High water level in a tropical freshwater wetland lowers CO2 flux but increases CH4 flux • A wetland’s role in climate change mitigation is a function of carbon sequestration and emission