Abstract  Lateral input of dissolved organics may play a significant role to support productivity in oligotrophic ocean although associated biogeochemical evidences are lacking in the field. Ammonia oxidation (AO), the first step of nitrification that bridges organic remineralization and nitrate, is potentially an immediate responder. By using N-15-NH4+, the spatial distribution of AO was investigated in the northern South China Sea, where Kuroshio Current intrudes frequently. AO ranged widely (0.001 to 134 nmol.L-1.day(-1)) in space and the depth-integrated (200 m) AO peaked where the Kuroshio influence is moderate suggesting that enhanced AO had occurred due to lateral mixing. Since oligotrophic Kuroshio is characterized by high dissolved organic nitrogen (DON), such lateral mixing not only introduces external DON into the northern South China Sea but also enhances NH4+ regeneration and subsequent oxidation to complicate the conventional new production in the boundary zone with DON gradient.

Plain Language Summary The horizontal mixing is widespread in oligotrophic ocean; however, the mixing-induced biogeochemical response is hard to detect and remains less explored. We measured ammonia oxidation (AO), a critical process immediately responds to remineralization of dissolved organic matter (DOM), along the pathway of Kuroshio intrusion into the South China Sea. We found AO peaked at stations where the influence of Kuroshio Current intrusion is moderate. We hypothesized that intrusion of oligotrophic water brings on-site recalcitrant DOM into marginal seas and enriches ammonium level via bacteria decomposition of the foreign DOM. Accompanied is the enhancement of AO, which transfers DOM into nitrate, further complicating the conventional concept of N-based new production. Such lateral intrusion or transport appears also along a meridional direction. For example, the western boundary current (warm and saline) carrying DOM-rich water flows toward higher latitudes where nutrients are high. According to our findings, such hemispheric scale transport may exert considerable influence on high-latitude nitrogen biogeochemistry. Knowledge of the impact of Kuroshio intrusion on AO in the northern South China Sea was a step forward in documenting this type of response in frontal zone, but more studies will be needed to validate the underlying mechanisms.

Abstract  Degradation of metronidazole (MNZ) by radio frequency discharge in water was examined. Results showed that (OH)-O-center dot, H-center dot, and O-center dot were produced. Decay of MNZ followed pseudo-first order kinetics, where the apparent rate constant was independent of its initial concentration in the range 0-0.5 mM, decreased in the range 0.5-1.0 mM, and leveled off in the range higher than 1.0 mM. pH had no effects on MNZ degradation. (OH)-O-center dot scavengers enhanced the MNZ removal. Formic acid, nitrite ion, oxalic acid, nitrate ion, and acetic acid were determined as the primary intermediate byproducts. The eventual products were ammonia and inorganic carbon. Both (OH)-O-center dot and H-center dot participated in the MNZ degradation. H-center dot played more efficient role than (OH)-O-center dot in the early stage.

Abstract  Qarun Lake, in the Fayoum Depression of the Western Desert of Egypt, lies within the deepest area in the River Nile flood plain. The drainage water in the Qarun Lake is derived from the discharge of the natural and artificial drainage systems in the Fayoum. Mixed domestic and agricultural pollutants, including heavy metals, nitrates, phosphates, sulfates and pesticides, are discharged into Qarun Lake. Forty-six samples, collected from the undisturbed layer of sediments were used for benthic foraminiferal analysis. Concentrations of some selected trace metal elements (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sr, V, and Zn) were also determined. Statistical analysis of the abiotic variables (Texture distribution of sediments, Physico-chemical parameters, and metals concentrations) and of the biotic variables (distribution of benthic foraminiferal species) were also performed. The Q-mode cluster analysis of benthic foraminiferal distribution has provided evidence that the Qarun Lake can be subdivided into two cluster groups (A and B), reflecting environmental changes in the lake ecosystem. Cluster B can also be subdivided into two sub-clusters (B1 and B2). The presence of only pollution tolerant taxa with higher faunal density and lower diversity and the absence of the other foraminiferal assemblages in cluster A were attributed to the high concentration of trace metal elements and the strong environmental stress at the eastern and central parts of the Qarun Lake. (C) 2017 Elsevier Ltd. All rights reserved.

Abstract  The geographical variation of denitrifying bacterial communities and water quality parameters in urban lakes distributed across nine provinces in China were determined. The Illumina sequencing data of the denitrifying encoding gene nirS was examined in the samples collected from nine localities (pairwise geographical distance: 200-2600 km). The results showed that fundamental differences in water quality were observed among different urban lakes. The highest nitrate (2.02 mg L-1) and total nitrogen (3.82 mg L-1) concentrations were observed in Pingzhuang (P < 0.01). The algal cell concentration ranged from 1.29 x 10(8) to 3.0 x 10(9) cell per L. The sequencing data generated a total of 421058 high quality nirS gene reads that resulted in 6369 OTUs (97% cutoff), with Proteobacteria and Firmicutes being the dominant taxa. A co-occurrence network analysis indicated that the top five genera identified as keystone taxa were Dechlorospirillum sp., Alicycliphilus sp., Dechloromonas sp., Pseudogulbenkiania sp., and Paracoccus sp. A redundancy analysis (RDA) further revealed that distinct denitrifying bacterial communities inhabited the different urban lakes, and influenced by urban lake water ammonia nitrogen, manganese and algal cell concentrations. A variance partitioning analysis (VPA) also showed that geographic location was more important than water quality factors in structuring the denitrifying bacterial communities. Together, these results provide new insight into understanding of denitrifying bacterial communities associated with geographically distributed urban lakes on a larger scale, and these results also expand our exploration of aquatic microbial ecology in freshwater bodies.

Abstract  The introduction of Ce4+ as a structural cation has been shown to be a promising route to redox active metal-organic frameworks (MOFs). However, the mechanism by which these MOFs act as redox catalysts remains unclear. Herein, we present a detailed study of the active site in [Ce6 O4 (OH)4 ]-based MOFs such as Ce-UiO-66, involved in the aerobic oxidation of benzyl alcohol, chosen as a model redox reaction. X-ray absorption spectroscopy (XAS) data confirm the reduction of up to one Ce4+ ion per Ce6 cluster with a corresponding outwards radial shift due to the larger radius of the Ce3+ cation, while not compromising the structural integrity of the framework, as evidenced by powder X-ray diffraction. This unambiguously demonstrates the involvement of the metal node in the catalytic cycle and explains the need for 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) as a redox mediator to bridge the gap between the one-electron oxidation of the Ce4+ /Ce3+ couple and the two-electron alcohol oxidation. Finally, an improved catalytic system with Ce-MOF-808 and TEMPO was developed which outperformed all other tested Ce4+ -MOFs.

Abstract  The optimization of biological nitrogen removal (BNR) in sequencing batch reactors has become the aim of researchers worldwide in order to increase efficiency and reduce energy and operating costs. This research has focused on the nitrification phase as the limiting reaction rate of BNR. This paper analyzes different strategies and discusses different tools such as: factors for achieving partial nitrification, real-time control and monitoring for detecting characteristic patterns of nitrification/denitrification as end-points, use of modeling based on activated sludge models, and the use of data-driven modeling for estimating variables that cannot be easily measured experimentally or online. The discussion of this paper highlight the properties and scope of each of these strategies, as well as their advantages and disadvantages, which can be integrated into future works using these strategies according to legal and economic restrictions for a more stable and efficient BNR process in the long-term.

Abstract  The ultrastructure of the living foraminiferan, Ammonia sp. (phylotype unknown), collected from surficial and deeper, subsurface (anoxic) sediments from the Dutch Wadden Sea, was examined to provide information on the physiology of the foraminiferal cell and its adaptive strategies to low-oxygen conditions. The observed changes in cell ultrastructure under anoxia were further compared with the cell ultrastructure of Ammonia sp. (phylotype T6), from oxic and anoxic incubation experiments. The ultrastructural evidence indicates that under low-oxygen conditions Ammonia spp. may accumulate lipid droplets. In addition, the size of the lipid droplets may increase with the duration of anoxic conditions, becoming over 5 mu m in size, while the remaining cytosol of the foraminiferan become less electron dense. In some specimens, lipid droplets were also found in the space between the plasma membrane and the organic lining. We expect that the apparent increase in the number and size of the lipid droplets is indicative of a stress response of the foraminifera to the adverse anoxic conditions. Other ultrastructural changes in response to anoxia include the presence of intact bacteria and electron dense opaque bodies within the foraminiferal cytosol, and a possible thickening of the organic lining. The role of the bacteria remains enigmatic but they may be linked to foraminiferal dormancy in anoxia.

Abstract  The thermal decomposition behaviors and burning characteristics of propellants prepared with combined ammonium perchlorate (AP)/ammonium nitrate (AN) particles greatly depended on the AN content (chi) of the AP/AN sample. The thermal decomposition behaviors of the propellants prepared with the combined samples almost matched those of the propellants prepared by physically mixing AP and AN particles, while their burning characteristics differed. The use of combined AP/AN particles decreased the heterogeneity of the combustion waves of the AP/AN propellants because of the difference in the combustion wave structure. In contrast, the addition of Fe2O3 caused unsteady combustion of the propellants prepared using samples with chi values lower than 8.1%.

Abstract  Improving fertility of marginal soils for the sustainable production of biomass is a strategy for reducing land use conflicts between food and energy crops. Digestates can be used as fertilizer and for soil amelioration. In order to promote plant growth and reduce potential adverse effects on roots because of broadcast digestate fertilization, we propose to apply local digestate depots placed into the rhizosphere. We grew Sida hermaphrodita in large mesocosms outdoors for three growing seasons and in rhizotrons in the greenhouse for 3 months both filled with marginal substrate, including multiple sampling dates. We compared digestate broadcast application with digestate depot fertilization and a mineral fertilizer control. We show that depot fertilization promotes a deep reaching root system of S. hermaphrodita seedlings followed by the formation of a dense root cluster around the depot-fertilized zone, resulting in a fivefold increased biomass yield. Temporal adverse effects on root growth were linked to high initial concentrations of ammonium and nitrite in the rhizosphere in either fertilizer application, followed by a high biomass increase after its microbial conversion to nitrate. We conclude that digestate depot fertilization can contribute to an improved cultivation of perennial energy-crops on marginal soils.

Abstract  The aim of the study was to assess a long-term impact of the cumulative application of sewage sludge on plant yield and soil microbial parameters. The study was conducted in 1 m(2) lysimeter plots. In 2006 sewage sludge was applied to selected plots at the rate of 100 t of dry matter per hectare while the other plots were fertilized with mineral nitrogen. After 6 years, the same sludge rate was applied to selected plots in order to achieve single or cumulative sludge rates. The sludge plots were compared to the plots constantly fertilized with ammonia nitrate and the plots treated with digestate. Sludge stimulated an increase in plant biomass similar or higher than the effect of mineral nitrogen fertilization. The highest enzyme activities were recorded for the cumulative sludge rates but the soils treated with single sludge rate also exhibited a high activity of alkaline phosphatase and dehydrogenases. The count of culturable microorganisms reflected trends observed for the enzyme activities. The study revealed that sewage sludges that meet the quality standards for application in agriculture stimulate both the soil microbial activity and the number of microorganisms even when applied at high reclamation rates. (C) 2018 Elsevier Ltd. All rights reserved.

Abstract  Air may be easily incorporated by vigorous mechanical stirring, with the help of surfactants, of activated geopolymer-yielding suspensions. The cellular structure is stabilized by the viscosity increase caused by curing reactions, configuring an inorganic gel casting. The present paper is aimed at extending this approach to mullite foams, obtained by the thermal treatment of engineered alkali activated suspensions. Green foams were first obtained by gel casting of a suspension for Na-geopolymer enriched with reactive -Al2O3 powders. Sodium was later extracted by ionic exchange with ammonium salts. In particular, the removal of Na+ ions was achieved by immersion in ammonium nitrate solution overnight, with retention of the cellular structure. Finally, the ion-exchanged foams were successfully converted into pure mullite foams by application of a firing treatment at 1300 degrees C, for 1hour. Preliminary results concerning the extension of the concept to mullite three-dimensional scaffolds are presented as well.

Abstract  Development and molecular engineering of new highly-efficient energetic biocidal materials is a significant challenge and of a great importance. Until now this type of materials included mostly halogen-rich nano-thermites and iodine-rich organic materials. So far, no energetic coordination polymers were reported as precursors for combustion-generated biocidal agents. Here, we demonstrate for the first time the synthesis of uniquely-structured three-dimensional energetic coordination polymer (ECP3) containing Zn metal centers and iodine- and nitrogen-rich bridging ligand (2). Upon its combustion, ECP3 is capable of generating gaseous reactive iodine species and elemental iodine-coated ZnO particles. ECP3 presents a novel approach for the design of efficient biocidal agents.

Abstract  Seven emulsion explosives were prepd. by mixing NH4NO3 (granules diam. 1-2 mm) with fuel oils (7 types) in a mass ratio of 94:6 and then examd. by IR spectroscopy, X-ray diffraction and scanning electron microscopy. The presence of numerous cracks, micropores and mesopores on the crystal surface of NH4NO3 was obsd. They facilitated enlarging the contact surface between NH(4)NO(3)crystals and fuel oil. The contact surface increased also with increasing the oil viscosity.

Abstract  Hydrothermal reaction of either cobalt or cadmium nitrate, D-camphoric acid (H(2)cam), and conformationally flexible dipyridylamide ligands produced five coordination networks which were structurally characterized by single-crystal X-ray diffraction. {[Co-2.DL-cam)(2).bdn)]center dot 2H(2)O}(n) (1, bdn = N, N'-(butane-1,4-diyl) dinicotinamide) possesses {Co-2(OCO)(4)} paddlewheel dimer-based [Co-2(DL-cam)(2)] grid layers pillared by bdn ligands into a 6-connected 4(12)6(3) pcu network. In contrast, the cadmium analog {[Cd-2(D-cam) (2)(bdn)(2)]center dot 5H(2)O}(n) (2) shows {Cd-2(OCO)(2)} dimer-based [Cd-2(D-cam)(2)] layers tethered by bdn ligands into an 8-connected 4(24)6(4) bcu network. {[Co-2(D-cam)(2)(pdn)]center dot 2H(2)O}(n) (3, pdn = N, N'-(propane-1,3-diyl) dinicotinamide) manifests a self-penetrated 4(4)6(8)10 mab network in contrast to 1, and retains chirality. {[Cd-2(D-cam)(2)(pdn)]center dot H2O}(n) (4) manifests {Cd-2(OCO)(4)} paddlewheel dimer-based [Cd-2(D-cam)(2)] grids, connected by exotridentate pbn ligands into a unique 3,7-connected 3D network with (3 center dot 5(2))(3(2)4(4)5(6)6(8)7) topology derived from a rare non-self-penetrated 4(9)6(6) acs topology sublattice. {[Co-2(DL-cam)(2)(pedn)] center dot 2H(2)O)(n) (5, pedn = N,N'-(pentane-1,5-diyl) dinicotinamide) shows a hybrid structure of discrete slabs of 3D pcu network with interleaved 2D hxl (3,6) layers at random intervals, instead of the self-penetrated mab network seen in 3. The specific coordination environments and dipyridylamide lengths result in control of topology and self-penetration in this series of coordination networks. The cadmium complexes 2 and 4 were assayed for luminescent and nitrobenzene detection properties. Thermal properties of 1-5 are also discussed.

Abstract  Biochar has been identified as a media amendment to improve nutrient removal from wastewater, and N retention and plant growth in agroforestry. It therefore has the potential for treating domestic wastewater. The aim of this research was to compare nitrogen removal and plant growth in pure sand and sand amended with biochar, in wetland mesocosms (240 L) receiving sewage. There were seven media treatments based on the proportions of biochar in the sand media (100% sand, sand and coir peat, 5, 10, 15, 20, 25% biochar). The plant species were Paperback tree (Melaleuca quinquenervia) and Lemongrass (Cymbopogon citratus). The mesocosms were continuously loaded for 8 months with secondary clarified wastewater (SCW) (16 L/day). Septage was then intermittently loaded (20 L/2 days) for a further 8 months. Inflow and outflow samples were monitored for TN, NH4-N, and NOx-N.

All treatments showed good nitrogen removal efficiency. Average removal efficiencies of TN, NOx-N and NH4-N in the mesocosms loaded with SCW ranged from 71 to 87%, 81 to 93% and 65 to 79%, for 100% Sand to 25% Biochar respectively. For septage, the removal efficiencies ranged from 63 to 81%, 69 to 87% and 66 to 81%, for 100% Sand to 25% Biochar respectively. Significant differences of nitrogen outflow concentrations were observed between pure sand and sand amended with biochar. Physical chemical properties of the biochar would have facilitated microbial processes and adsorption. Strong positive correlations were observed between biochar content in the media and nitrogen removal rates. The increased nitrogen removal may be attributed to higher mineralisation of organic nitrogen and NH4-N, especially in the case of septage where strong correlation was observed between BOD5 and TN removal. Total N biomass in the plants harvested after 21 months ranged from 13.4-14.0 g N. The addition of biochar did not increase plant N biomass in either species.

Abstract  Ingestion of geophagic materials might affect human health and induce diseases by different ways. The purpose of this study is to determine the geochemical composition of geophagic material consumed especially by pregnant women in Onangama Village, Northern Namibia and to assess its possible health effects. X-ray fluorescence and inductively coupled plasma mass spectrometry were used in order to determine the major, and trace elements as well as anions concentrations of the consumed material. The geochemical analysis revealed high concentrations of aluminium (Al), calcium (Ca), iron (Fe), magnesium (Mg), manganese (Mn), potassium (K), sodium (Na), and silica (Si); and trace elements including arsenic (As), chromium (Cr), mercury (Hg), nickel (Ni) and vanadium (V) as well as sulphate (SO42-), nitrate (NO3-), and nitrite (NO2-) anions comparing to the recommended daily allowance for pregnant women. The pH for some of the studied samples is alkaline, which might increase the gastrointestinal tract pH (pH < 2) and cause a decrease in the bioavailability of elements. The calculated health risk index (HRI > 1) revealed that Al and Mn might be a potential risk for human consumption. Based on the results obtained from the geochemical analysis, the consumption of the studied material might present a potential health risk to pregnant women including concomitant detrimental maternal and foetal effects.

Abstract  To understand the physiological responses of the brown macroalga Macrocystis integrifolia during the marine tidal cycle, two RNA libraries were prepared from algal frond samples collected in the intertidal zone (0 m depth) and subtidal zone (10 m depth). Samples collected from intertidal zone during low tide was considered as abiotic stressed (MI0), while samples collected from subtidal zone was considered as control (MI10). Both RNA libraries were sequenced on Illumina NextSeq 500 which generated approx. 46.9 million and 47.7 million raw paired-end reads for MI0 and MI10, respectively. Among the representative transcripts (RTs), a total of 16,398 RTs (39.20%) from MI0 and 21,646 RTs (39.24%) from MI10 were successfully annotated. A total of 535 unigenes (271 upregulated and 264 downregulated) showed significantly altered expression between MI0 and MI10. In abiotic-stressed condition (MI0), the relative expression levels of genes associated with antioxidant defenses (vanadium-dependent bromoperoxidase, glutathione S-transferase, lipoxygenase, serine/threonine-protein kinase, aspartate Aminotransferase, HSPs), water transport (aquaporin), photosynthesis (light-harvesting complex) protein were significantly upregulated, while in control condition (MI10) most of the genes predominantly involved in energy metabolism (NADH-ubiquinone oxidoreductase/NADH dehydrogenase, NAD(P)H-Nitrate reductase, long-chain acyl-CoA synthetase, udp-n-acetylglucosamine pyrophosphorylase) were overexpressed.

Abstract  Nitric oxide (NO) has wide-ranging roles in biology, but less is known about its role in building chemical diversity. Here we report a new route to NO from the biosynthetic pathway to the N-nitroso compound streptozocin. We show that the N-nitroso group of streptozocin comes from the biosynthetic reassembly of l-arginine, with the guanidino nitrogens forming a nitrogen-nitrogen bond. To understand this biosynthetic process, we identify the biosynthetic gene cluster of streptozocin and demonstrate that free l-arginine is N-methylated by StzE to give Nω-monomethyl-l-arginine. We show that this product is then oxidized by StzF, a nonheme iron-dependent enzyme unrelated to known nitric oxide synthases, generating a urea compound and NO. Our work implies that formation and capture of NO is the likely route to N-nitroso formation in vivo. Altogether, our work unveils a new enzyme pair for the production of NO from l-arginine and sets the stage for understanding biosynthetic routes to N-nitroso natural products.

Abstract  Organohalide-respiring bacteria are key players for the turnover of organohalogens. At sites impacted with chlorinated ethenes, bioremediation promotes reductive dechlorination; however, stoichiometric conversion to environmentally benign ethene is not always achieved. We demonstrate that nitrous oxide (N2O), a compound commonly present in groundwater, inhibits organohalide respiration. N2O concentrations in the low micromolar range decreased dechlorination rates and resulted in incomplete dechlorination of tetrachloroethene (PCE) in Geobacter lovleyi strain SZ and of cis-1,2-dichloroethene ( cDCE) and vinyl chloride (VC) in Dehalococcoides mccartyi strain BAV1 axenic cultures. Presumably, N2O interferes with reductive dechlorination by reacting with super-reduced Co(I)-corrinoids of reductive dehalogenases, which is supported by the finding that N2O did not inhibit corrinoid-independent fumarate-to-succinate reduction in strain SZ. Kinetic analyses revealed a best fit to the noncompetitive Michaelis-Menten inhibition model, and determined N2O inhibitory constants, KI, for PCE and cDCE dechlorination of 40.8 ± 3.8 µM and 21.2 ± 3.5 µM in strain SZ and strain BAV1, respectively. The lowest KI value of 9.6 ± 0.4 µM was determined for VC to ethene reductive dechlorination in strain BAV1, suggesting that this crucial dechlorination step for achieving detoxification is most susceptible to N2O inhibition. Groundwater N2O concentrations exceeding 100 µM are not uncommon, especially in watersheds impacted by nitrate runoff from agricultural sources. Thus, dissolved N2O measurements can inform about cDCE and VC stalls at sites impacted with chlorinated ethenes.

Abstract  The use of the heteroleptic [Cr-III(AA)(CN)(4)]-complexes as ligands towards the preformed [Mn-II(tptz)](2+) and [Mn-II(pyim)(2)](2+) species afforded the heterometallic compounds of formula [Mn-II(tptz)(H2O)(NO3)(mu-NC)Cr-III(ampy)(CN)(3)]center dot CH3CN (1), [Mn-II(tptz)(H2O)(NO3)(mu-NC) Cr-III(phen)(CN)(3)]center dot H2O (2) and {[Mn-II(pyim)(2)][(mu-NC) Cr(phen)(CN)(3)](2)}center dot 3H(2)O (3) [AA = 2-amino-methylpyridine (ampy) and 1,10-phenanthroline (phen), tptz = 2,4,6-tris(2-pyridyl)-1,3,5-triazine and pyim = 2-(1H-imidazol-2yl) pyridine]. 1 and 2 are neutral heterodinuclear complexes, where the [Cr-III(AA)(CN) 4]-building block acts as a monodentate ligand through one of its four cyanido groups towards a manganese(II) ion with seven coordination sites completed by a tridenate tptz molecule, a bidentate nitrate anion and a water molecule. Compound 3 is a neutral heterotrinuclear complex made up by two peripheral [Cr-III(AA)(CN)(4)](-) units acting as monodentate ligands through one of their cyanido groups towards an inner [Mn-II(pyim)(2)](2+) entity. Each manganese(II) ion in 3 is six-coordinate with two cyanido nitrogen atoms and two bidentate pyim molecules, building a distorted octahedral surrounding. The values of the Cr-III-Mn-II distance across the bridging cyanido ligand are 5.3766(7) (1), 5.3194(6) (2) and 5.3245(8) and 5.4538(7) angstrom (3). The magnetic properties of 1-3 were investigated in the temperature range 1.9-300 K. Overall antiferromagnetic behaviour is observed for all three compounds, with the antiparallel alignment of the local spins leading to either a ground-state spin triplet (1 and 2) or a spin doublet (3). The values of the magnetic coupling between the Cr-III and Mn-II ions across the single cyanido bridges are J = -7.40(2) (1), -6.65(2) (2) and -6.41(2) and -4.65(2) cm(-1) (3), with the spin Hamiltonian being defined as H = -J(S-Cr1 center dot S-Mn1) (1 and 2) and H = -J(1)(S-Cr1 center dot S-Mn1) - J(2)(S-Cr2 center dot S-Mn2) (3). These values could be correlated with the Mn-N-Ccyanido angle, and they agree with those reported for this exchange pathway in other magnetostructural studies.

Abstract  Breeding for pollution-safe cultivars (PSCs) can reduce pollutant accumulation in crops. However, the PSC breeding would face the risk of nutritional quality reduction, which is usually ignored in conventional breeding programs targeting to increase crop yield or nutritional quality. Thus, the doubt whether the risk would exist has to be clarified for supporting the PSC breeding. In the present study, a newly bred Cd/Pb-PSC of water spinach (Ipomoea aquatic Forsk.) and its parents (QLQ with low-Cd/Pb accumulation ability and T308 with high yield) of water spinach were employed to clarify the above-mentioned issue. Yields, and concentrations of Cd, Pb, nitrite, and organic and inorganic nutrients in shoots of the three experimental lines were determined. There were no significant differences in Cd/Pb concentration between the new PSC and QLQ, in nitrite content between the new PSC and its two parents and in yield between the new PSC and T308. It is decisively significant that shoot concentrations of organic and inorganic nutrients in the Cd/Pb-PSC were as high as those in one of its parents. It is affirmed that the breeding operations (crossing and consequently continuous selfing) for lowering Cd/Pb accumulation capacity of water spinach would not lower the nutritional values of the obtained Cd/Pb-PSCs from the breeding, which should be a pillar that supports the feasibility to minimize Cd/Pb pollution in vegetables using PSC-breeding method.

Abstract  Speciated monoterpene measurements in rainforest air are scarce, but they are essential for understanding the contribution of these compounds to the overall reactivity of volatile organic compound (VOC) emissions towards the main atmospheric oxidants, such as hydroxyl radicals (OH), ozone (O-3) and nitrate radicals (NO3). In this study, we present the chemical speciation of gas-phase monoterpenes measured in the tropical rainforest at the Amazon Tall Tower Observatory (ATTO, Amazonas, Brazil). Samples of VOCs were collected by two automated sampling systems positioned on a tower at 12 and 24m height and analysed using gas chromatography-flame ionization detection. The samples were collected in October 2015, representing the dry season, and compared with previous wet and dry season studies at the site. In addition, vertical profile measurements (at 12 and 24 m) of total monoterpene mixing ratios were made using proton-transfer-reaction mass spectrometry. The results showed a distinctly different chemical speciation between day and night. For instance, alpha-pinene was more abundant during the day, whereas limonene was more abundant at night. Reactivity calculations showed that higher abundance does not generally imply higher reactivity. Furthermore, inter-and intra-annual results demonstrate similar chemodiversity during the dry seasons analysed. Simulations with a canopy exchange modelling system show simulated monoterpene mixing ratios that compare relatively well with the observed mixing ratios but also indicate the necessity of more experiments to enhance our understanding of in-canopy sinks of these compounds.

Abstract  To test the effect of Crassostrea virginica biodeposit resuspension on nutrient and plankton dynamics, a 4 wk experiment was performed in six 1000 l shear-turbulence-resuspension-mesocosms (STURM) without a sediment bottom (R). Three tanks (R_BD) received daily additions of oyster biodeposits (5.77 +/- 3.33 mg total suspended solids). Simulated tidal resuspension of bio-deposits in the R_BD tanks resulted in concentrations of 90 mg l(-1) total suspended solids when mixing was on, decreasing to ca. 20 mg l(-1) when mixing was off. However, bulk settling speeds of particles in the R_BD tanks increased 3-fold over the experiment. Particulate nitrogen, phosphorus, and carbon concentrations as well as dissolved inorganic nitrogen, nitrate + nitrite, dissolved organic phosphorus, and total dissolved phosphorus levels were significantly higher in the R_BD tanks. In the R_BD tanks the greatest part (72%) of the nitrogen was partitioned in the total dissolved nitrogen, but in the R tanks the greatest part (51.5%) was partitioned in microphytobenthos. While chlorophyll a concentrations were higher in the R_BD tanks than in the R tanks (despite tunicates being found in the R_BD tanks), phytoplankton biomass (carbon) as estimated using direct cell counts was not significantly different and there was little difference in phytoplankton composition. However, the ratio of chl a:C was higher in the R_BD tanks, suggesting phytoplankton adjusted to low light in the R_BD tanks by increasing chl a in their cells. Acartia sp. abundance was also raised in the R_BD tanks. Addition and regular tidal resuspension of oyster biodeposits profoundly affected nutrient dynamics, nitrogen partitioning, and zooplankton community dynamics.

Abstract  MAIN CONCLUSION: An SPL-type transcription factor, LeSPL-CNR, is negatively involved in NO production by modulating SlNR expression and nitrate reductase activity, which contributes to Cd tolerance. Cadmium (Cd) is a highly toxic pollutant. Identifying factors affecting Cd accumulation in plants is a prerequisite for minimizing dietary uptake of Cd from crops grown with contaminated soil. Here, we report the involvement of a SQUAMOSA PROMOTER-BINDING PROTEIN-LIKE (SPL) transcription factor LeSPL-CNR in Cd tolerance in tomato (Solanum lycopersicum). In comparison with the wild-type Ailsa Craig (AC) plants, the Colourless non-ripening (Cnr) epimutant displayed increased Cd accumulation and enhanced sensitivity to Cd, which was in well accordance with the repression of LeSPL-CNR expression. Cd stress-induced NO production was inhibited by nitrate reductase (NR) inhibitor, but not NO synthase-like enzyme inhibitor. Expression of LeSPL-CNR was negatively correlated with SlNR expression and the NR activity. We also demonstrated that LeSPL-CNR inhibited the SlNR promoter activity in vivo and bound to SlNR promoter sequence that does not contain a known SBP-binding motif. In addition, expression of an IRON-REGULATED TRANSPORTER1, SlIRT1, was more abundant in Cnr roots than AC roots under Cd stress. LeSPL-CNR may thus provide a molecular mechanism linking Cd stress response to regulation of NR-dependent NO production, which then contributes to Cd uptake via SlIRT1 expression in tomato.