Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Patterns of nitrogen-fixing tree abundance in forests across Asia and America
Menge, Duncan N.L. ; Chisholm, Ryan A. ; Davies, Stuart J. ; Abu Salim, Kamariah ; Allen, David ; Alvarez, Mauricio ; Bourg, Norm ; Brockelman, Warren Y. ; Bunyavejchewin, Sarayudh ; Butt, Nathalie ; Cao, Min ; Chanthorn, Wirong ; Chao, Wei Chun ; Clay, Keith ; Condit, Richard ; Cordell, Susan ; Silva, João Batista da; Dattaraja, H.S. ; Andrade, Ana Cristina Segalin de; Oliveira, Alexandre A. de; Ouden, Jan den; Drescher, Michael ; Fletcher, Christine ; Giardina, Christian P. ; Savitri Gunatilleke, C.V. ; Gunatilleke, I.A.U.N. ; Hau, Billy C.H. ; He, Fangliang ; Howe, Robert ; Hsieh, Chang Fu ; Hubbell, Stephen P. ; Inman-Narahari, Faith M. ; Jansen, Patrick A. ; Johnson, Daniel J. ; Kong, Lee Sing ; Král, Kamil ; Ku, Chen Chia ; Lai, Jiangshan ; Larson, Andrew J. ; Li, Xiankun ; Li, Yide ; Lin, Luxiang ; Lin, Yi Ching ; Liu, Shirong ; Lum, Shawn K.Y. ; Lutz, James A. ; Ma, Keping ; Malhi, Yadvinder ; McMahon, Sean ; McShea, William ; Mi, Xiangcheng ; Morecroft, Michael ; Myers, Jonathan A. ; Nathalang, Anuttara ; Novotny, Vojtech ; Ong, Perry ; Orwig, David A. ; Ostertag, Rebecca ; Parker, Geoffrey ; Phillips, Richard P. ; Abd. Rahman, Kassim ; Sack, Lawren ; Sang, Weiguo ; Shen, Guochun ; Shringi, Ankur ; Shue, Jessica ; Su, Sheng Hsin ; Sukumar, Raman ; Fang Sun, I. ; Suresh, H.S. ; Tan, Sylvester ; Thomas, Sean C. ; Toko, Pagi S. ; Valencia, Renato ; Vallejo, Martha I. ; Vicentini, Alberto ; Vrška, Tomáš ; Wang, Bin ; Wang, Xihua ; Weiblen, George D. ; Wolf, Amy ; Xu, Han ; Yap, Sandra ; Zhu, Li ; Fung, Tak - \ 2019
Journal of Ecology (2019). - ISSN 0022-0477
forest - legume - nitrogen fixation - nutrient limitation - Smithsonian ForestGEO - symbiosis

Symbiotic nitrogen (N)-fixing trees can provide large quantities of new N to ecosystems, but only if they are sufficiently abundant. The overall abundance and latitudinal abundance distributions of N-fixing trees are well characterised in the Americas, but less well outside the Americas. Here, we characterised the abundance of N-fixing trees in a network of forest plots spanning five continents, ~5,000 tree species and ~4 million trees. The majority of the plots (86%) were in America or Asia. In addition, we examined whether the observed pattern of abundance of N-fixing trees was correlated with mean annual temperature and precipitation. Outside the tropics, N-fixing trees were consistently rare in the forest plots we examined. Within the tropics, N-fixing trees were abundant in American but not Asian forest plots (~7% versus ~1% of basal area and stems). This disparity was not explained by mean annual temperature or precipitation. Our finding of low N-fixing tree abundance in the Asian tropics casts some doubt on recent high estimates of N fixation rates in this region, which do not account for disparities in N-fixing tree abundance between the Asian and American tropics. Synthesis. Inputs of nitrogen to forests depend on symbiotic nitrogen fixation, which is constrained by the abundance of N-fixing trees. By analysing a large dataset of ~4 million trees, we found that N-fixing trees were consistently rare in the Asian tropics as well as across higher latitudes in Asia, America and Europe. The rarity of N-fixing trees in the Asian tropics compared with the American tropics might stem from lower intrinsic N limitation in Asian tropical forests, although direct support for any mechanism is lacking. The paucity of N-fixing trees throughout Asian forests suggests that N inputs to the Asian tropics might be lower than previously thought.

E-MTAB-7487 - RNA-seq analysis of Clostridium beijerinckii DSM 6423 at early exponential, acetogenic, and solventogenic growth phase on rhamnose compared to glucose
Diallo, M. ; Simons, Andre ; Wal, H. van der; Collas, Florent ; Houweling-Tan, G.B.N. ; Kengen, S.W.M. ; Lopez Contreras, A.M. - \ 2019
E-MTAB-7487 - ERP112812 - PRJEB30358 - Clostridium beijerinckii
This experiment aim was to characterize the catabolism of L-rhamnose of Clostridium beijerinckii DSM 6423 by transcriptomic analysis, generating new insights and knowledge on utilization of L-rhamnose for production of chemicals, including Isopropanol, Butanol, Ethanol (IBE) and 1,2-propandiol. These analysis on cultures grown on L-rhamnose compared to D-glucose grown cultures showed upregulation of the L-rhamnose-related clusters and genes, and lower expression of the solventogenic genes, which was reflected in the products formed.
Impact of low-molecular weight organic acids on selenite immobilization by goethite: Understanding a competitive-synergistic coupling effect and speciation transformation
Fang, Dun ; Wei, Shiyong ; Xu, Yun ; Xiong, Juan ; Tan, Wenfeng - \ 2019
Science of the Total Environment 684 (2019). - ISSN 0048-9697 - p. 694 - 704.
Adsorption - Ferric selenite - Organic acids - Reduction - Selenium - Speciation transformation
© 2019 Elsevier B.V. The interactions between low-molecular weight organic acids (LMWOAs)and selenium (Se)on mineral/water interfaces affect the release, immobilization and bioavailability of Se in nature. Herein, the effects of three environmentally relevant LMWOAs (i.e., oxalic (Oxa), succinic (Suc)and citric (Cit)acids)on Se(IV)adsorption to goethite under oxic conditions were investigated using batch experiments, speciation fractionation, and ATR-FTIR and XPS analyses. The LMWOAs exhibited a competitive-synergistic coupling effect on Se(IV)adsorption to goethite, which inhibited the adsorption rate of Se(IV)by 14.1, 13.3 and 8.0 times. However, immobilization of Se(IV)was simultaneously enhanced by 39.1%, 34.6% and 14.1% in the following order Oxa > Suc > Cit. The results obtained by fractionation of the adsorbed Se(IV)revealed that the enhancement was due to surface binding as well as speciation transformation from ligand-exchangeable Se(IV)into residual fractions, which increased by approximately 18% in the presence of the LMWOAs. The dissolution of goethite significantly improved due to the LMWOAs and decreased to different degrees as the concentration of Se(IV)increased. The monodentate mononuclear complexes (58.2%)and Lewis base sites bonded Se (41.8%)were the predominant surface species of Se(IV)in goethite-Se(IV)system. The ATR-FTIR and high-resolution XPS analyses demonstrated that the formation of ≡FeO(SeO)O-CO surface complexes (22.8–27.0%)occurred in the presence of LMWOAs, which could be closely correlated with the interface-mediated reduction of Se(IV). In addition, the predominant mechanism for the formation of residual Se is LMWOA specific, in which ferric selenite-like precipitation was dominant for Suc (10.6%)and Cit (11.6%)and reduction was dominant for Oxa (17.5%). Overall, LMWOAs play an important role in Se(IV)immobilization and speciation transformation and may facilitate understanding the Se bioavailability in rhizosphere soils under oxic conditions.
Discovery of Salmonella trehalose phospholipids reveals functional convergence with mycobacteria
Reinink, Peter ; Buter, Jeffrey ; Mishra, Vivek K. ; Ishikawa, Eri ; Cheng, Tan Yun ; Willemsen, Peter T.J. ; Porwollik, Steffen ; Brennan, Patrick J. ; Heinz, Eva ; Mayfield, Jacob A. ; Dougan, Gordon ; Els, Cécile A. van; Cerundolo, Vincenzo ; Napolitani, Giorgio ; Yamasaki, Sho ; Minnaard, Adriaan J. ; McClelland, Michael ; Moody, D.B. ; Rhijn, Ildiko Van - \ 2019
Journal of Experimental Medicine 216 (2019)4. - ISSN 0022-1007 - p. 757 - 771.

Salmonella species are among the world's most prevalent pathogens. Because the cell wall interfaces with the host, we designed a lipidomics approach to reveal pathogen-specific cell wall compounds. Among the molecules differentially expressed between Salmonella Paratyphi and S. Typhi, we focused on lipids that are enriched in S. Typhi, because it causes typhoid fever. We discovered a previously unknown family of trehalose phospholipids, 6,6'-diphosphatidyltrehalose (diPT) and 6-phosphatidyltrehalose (PT). Cardiolipin synthase B (ClsB) is essential for PT and diPT but not for cardiolipin biosynthesis. Chemotyping outperformed clsB homology analysis in evaluating synthesis of diPT. DiPT is restricted to a subset of Gram-negative bacteria: large amounts are produced by S. Typhi, lower amounts by other pathogens, and variable amounts by Escherichia coli strains. DiPT activates Mincle, a macrophage activating receptor that also recognizes mycobacterial cord factor (6,6'-trehalose dimycolate). Thus, Gram-negative bacteria show convergent function with mycobacteria. Overall, we discovered a previously unknown immunostimulant that is selectively expressed among medically important bacterial species.

Loss of function mutations in essential genes cause embryonic lethality in pigs
Derks, Martijn F.L. ; Gjuvsland, Arne B. ; Bosse, Mirte ; Lopes, Marcos S. ; Son, Maren van; Harlizius, Barbara ; Tan, Beatrice F. ; Hamland, Hanne ; Grindflek, Eli ; Groenen, Martien A.M. ; Megens, Hendrik Jan - \ 2019
Plos Genetics 15 (2019)3. - ISSN 1553-7404 - p. e1008055 - e1008055.

Lethal recessive alleles cause pre- or postnatal death in homozygous affected individuals, reducing fertility. Especially in small size domestic and wild populations, those alleles might be exposed by inbreeding, caused by matings between related parents that inherited the same recessive lethal allele from a common ancestor. In this study we report five relatively common (up to 13.4% carrier frequency) recessive lethal haplotypes in two commercial pig populations. The lethal haplotypes have a large effect on carrier-by-carrier matings, decreasing litter sizes by 15.1 to 21.6%. The causal mutations are of different type including two splice-site variants (affecting POLR1B and TADA2A genes), one frameshift (URB1), and one missense (PNKP) variant, resulting in a complete loss-of-function of these essential genes. The recessive lethal alleles affect up to 2.9% of the litters within a single population and are responsible for the death of 0.52% of the total population of embryos. Moreover, we provide compelling evidence that the identified embryonic lethal alleles contribute to the observed heterosis effect for fertility (i.e. larger litters in crossbred offspring). Together, this work marks specific recessive lethal variation describing its functional consequences at the molecular, phenotypic, and population level, providing a unique model to better understand fertility and heterosis in livestock.

The concept of load ratio applied to bioelectrochemical systems for ammonia recovery
Rodríguez Arredondo, Mariana ; Kuntke, Philipp ; Heijne, Annemiek ter; Buisman, Cees J.N. - \ 2019
Journal of Chemical Technology and Biotechnology 94 (2019)6. - ISSN 0268-2575 - p. 2055 - 2061.
ammonia recovery - ammonia removal - bioelectrochemical systems - urine treatment

BACKGROUND: The load ratio is a crucial parameter to optimize the current driven recovery of total ammonia nitrogen (TAN) from urine. The load ratio is the ratio between the current density and the TAN loading rate. It is currently not known if the load ratio concept applies to a bioelectrochemical system (BES) because the current density and TAN loading rate cannot be controlled independently. RESULTS: We found a clear increasing trend in TAN removal efficiency with respect to load ratio in the BES for both human and synthetic urine. The maximum TAN removal efficiency was 60.9% at a load ratio of 0.7, corresponding to a TAN transport rate of 119 gN m −2 day −1 at an electrical energy input of 1.9 kWh kgN −1 (synthetic urine). Low load ratios (<1) were obtained, indicating that the current was not enough to transport all the TAN across the membrane. CONCLUSIONS: BES and ES show the same general relationship between TAN removal efficiency and load ratio. Therefore, given a stable current density, the concept of load ratio can also predict the TAN removal efficiency in BES. Higher current densities, and insights into the factors limiting current, are needed to increase the load ratio and therefore the TAN removal efficiency.

Methodology for estimating emissions from agriculture in the Netherlands : Calculations of CH4, NH3, N2O, NOx, NMVOC, PM10, PM2.5 and CO2 with the National Emission Model for Agriculture (NEMA), Update 2019
Lagerwerf, L.A. ; Bannink, A. ; Bruggen, C. van; Groenestein, C.M. ; Huijsmans, J.F.M. ; Kolk, J.W.H. van der; Luesink, H.H. ; Sluis, S.M. van der; Velthof, G.L. ; Vonk, J. - \ 2019
Wageningen : Statutory Research Tasks Unit for Nature & the Environment (WOt technical report 148) - 215
The National Emission Model for Agriculture (NEMA) is used to calculate emissions to air from agricultural activities in the Netherlands on a national scale. Emissions of ammonia (NH3) and other N compounds (NOx and N2O) are calculated for animal housing, manure storage, manure application and grazing using a flow model for total ammoniacal nitrogen (TAN). Emissions from the application of inorganic N fertilizer, compost and sewage sludge, cultivation of organic soils, crop residues, and ripening of crops are calculated as well. The NEMA is also used to estimate emissions of methane (CH4) from enteric fermentation and manure management, nonmethane volatile organic compounds (NMVOC) and particulate matter (PM) from manure management and agricultural soils, as well as for carbon dioxide (CO2) from liming. Emissions are calculated in accordance with the criteria of international guidelines and reported in an annual Informative Inventory Report (IIR; for air pollutants) and National Inventory Report (NIR; for greenhouse gases). This methodology report provides an outline of and describes the background to the calculation of emissions according to the NEMA.
Modelling the combined effect of moisture and temperature on secondary infection in a coupled host-pathogen FSPM
Streit, Katarina ; Evers, Jochem B. ; Renton, Michael - \ 2019
In: Proceedings - 2018 6th International Symposium on Plant Growth Modeling, Simulation, Visualization and Applications, PMA 2018. - Institute of Electrical and Electronics Engineers Inc. - ISBN 9781538678152 - p. 61 - 68.
disease modelling - functional-structural plant modelling - leaf wetness duration - moisture - tan spot - temperature - yellow spot

Weather conditions are an important driver of disease development. For example for yellow spot in wheat, warm and moist conditions favour secondary infection. Although the relationship between environment and disease development is the basis of many epidemiological models, changes in plant architecture and growth have an effect on disease progress and severity as well. Functional-structural plant models (FSPMs) are well suited to study the interactions between pathogen, climatic conditions and growing host crop. In this study we focused on simulating the effect of weather conditions on the progression of secondary infection in yellow spot and the interaction with growing wheat canopy. Simulations were performed using a coupled host-pathogen FSPM with standard meteorological data input. The model develops on previous coupled host-pathogen FSPMs by combining response functions to temperature and wetness duration and calculating the hourly progression of secondary infection. The simulated diseased area differed with different combinations of temperature and moisture response models. Changes in dispersal pattern were observed mainly in relation to spore release rate.

l-Rhamnose Metabolism in Clostridium beijerinckii Strain DSM 6423
Diallo, Mamou ; Simons, Andre D. ; Wal, Hetty van der; Collas, Florent ; Houweling-Tan, Bwee ; Kengen, Servé W.M. ; López-Contreras, Ana M. - \ 2019
Applied and Environmental Microbiology 85 (2019)5. - ISSN 0099-2240
1,2-propanediol - IBE fermentation - l-rhamnose - propionic acid - Ulva lactuca

Macroalgae (or seaweeds) are considered potential biomass feedstocks for the production of renewable fuels and chemicals. Their sugar composition is different from that of lignocellulosic biomasses, and in green species, including Ulva lactuca, the major sugars are l-rhamnose and d-glucose. C. beijerinckii DSM 6423 utilized these sugars in a U. lactuca hydrolysate to produce acetic acid, butyric acid, isopropanol, butanol, and ethanol (IBE), and 1,2-propanediol. d-Glucose was almost completely consumed in diluted hydrolysates, while l-rhamnose or d-xylose was only partially utilized. In this study, the metabolism of l-rhamnose by C. beijerinckii DSM 6423 was investigated to improve its utilization from natural resources. Fermentations on d-glucose, l-rhamnose, and a mixture of d-glucose and l-rhamnose were performed. On l-rhamnose, the cultures showed low growth and sugar consumption and produced 1,2-propanediol, propionic acid, and n-propanol in addition to acetic and butyric acids, whereas on d-glucose, IBE was the major product. On a d-glucose-l-rhamnose mixture, both sugars were converted simultaneously and l-rhamnose consumption was higher, leading to high levels of 1,2-propanediol (78.4 mM), in addition to 59.4 mM butanol and 31.9 mM isopropanol. Genome and transcriptomics analysis of d-glucose- and l-rhamnose-grown cells revealed the presence and transcription of genes involved in l-rhamnose utilization and in bacterial microcompartment (BMC) formation. These data provide useful insights into the metabolic pathways involved in l-rhamnose utilization and the effects on the general metabolism (glycolysis, early sporulation, and stress response) induced by growth on l-rhamnose.IMPORTANCE A prerequisite for a successful biobased economy is the efficient conversion of biomass resources into useful products, such as biofuels and bulk and specialty chemicals. In contrast to other industrial microorganisms, natural solvent-producing clostridia utilize a wide range of sugars, including C5, C6, and deoxy-sugars, for production of long-chain alcohols (butanol and 2,3-butanediol), isopropanol, acetone, n-propanol, and organic acids. Butanol production by clostridia from first-generation sugars is already a commercial process, but for the expansion and diversification of the acetone, butanol, and ethanol (ABE)/IBE process to other substrates, more knowledge is needed on the regulation and physiology of fermentation of sugar mixtures. Green macroalgae, produced in aquaculture systems, harvested from the sea or from tides, can be processed into hydrolysates containing mixtures of d-glucose and l-rhamnose, which can be fermented. The knowledge generated in this study will contribute to the development of more efficient processes for macroalga fermentation and of mixed-sugar fermentation in general.

Social learning as an analytical lens for co-creative planning
Schönfeld, Kim von; Tan, W.G.Z. ; Wiekens, Carina ; Salet, Willem ; Janssen-Jansen, Leonie - \ 2019
European Planning Studies 27 (2019)7. - ISSN 0965-4313 - p. 1291 - 1313.
This article highlights the psychological dimension of social learning. Insights from psychology address the interrelated role of personal and group dynamics in social learning. This can provide a useful starting point for a rewarding use of social learning as an analytical tool in co-creative planning. Such an approach to social learning proves beneficial to (i) identify both positive and negative potential effects of social learning, (ii) untangle hidden power relationships at play at individual and small group levels in relation to social psychological factors, and (iii) discern the role of individuals and small groups within their larger contexts. The findings are empirically illustrated with a case of incremental urban development in Groningen, the Netherlands.
Unpacking social learning in planning: who learns what from whom?
Schönfeld, Kim von; Tan, W.G.Z. ; Wiekens, Carina ; Janssen-Jansen, Leonie - \ 2019
Urban Research & Practice (2019). - ISSN 1753-5069
Social learning is the process of exchanging and developing knowledge (including skills and experiences) through human interaction. This key planning process needs to be better under-stood, given the increase and variety of non-planners influencing planning processes. This article explores who learns what from whom through social learning in planning. We unpack social learning theoretically to be able to map it, and employ empirically-based storytelling to discuss its relevance to planning practice. We conclude that social learning can lead to positive and negative outcomes and provides a useful analytical lens to understand planning practices at the level of individuals.
Next generation physiologically based kinetic (NG-PBK) models in support of regulatory decision making
Paini, A. ; Leonard, J.A. ; Joossens, E. ; Bessems, J.G.M. ; Desalegn, A. ; Dorne, J.L. ; Gosling, J.P. ; Heringa, M.B. ; Klaric, M. ; Kliment, T. ; Kramer, N.I. ; Loizou, G. ; Louisse, J. ; Lumen, A. ; Madden, J.C. ; Patterson, E.A. ; Proença, S. ; Punt, A. ; Setzer, R.W. ; Suciu, N. ; Troutman, J. ; Yoon, M. ; Worth, A. ; Tan, Y.M. - \ 2019
Computational Toxicology 9 (2019). - ISSN 2468-1113 - p. 61 - 72.
In silico - In vitro - PBPK - PBTK - Physiologically based kinetic models - Toxicokinetics

The fields of toxicology and chemical risk assessment seek to reduce, and eventually replace, the use of animals for the prediction of toxicity in humans. In this context, physiologically based kinetic (PBK) modelling based on in vitro and in silico kinetic data has the potential to a play significant role in reducing animal testing, by providing a methodology capable of incorporating in vitro human data to facilitate the development of in vitro to in vivo extrapolation of hazard information. In the present article, we discuss the challenges in: 1) applying PBK modelling to support regulatory decision making under the toxicology and risk-assessment paradigm shift towards animal replacement; 2) constructing PBK models without in vivo animal kinetic data, while relying solely on in vitro or in silico methods for model parameterization; and 3) assessing the validity and credibility of PBK models built largely using non-animal data. The strengths, uncertainties, and limitations of PBK models developed using in vitro or in silico data are discussed in an effort to establish a higher degree of confidence in the application of such models in a regulatory context. The article summarises the outcome of an expert workshop hosted by the European Commission Joint Research Centre (EC-JRC) – European Union Reference Laboratory for Alternatives to Animal Testing (EURL ECVAM), on “Physiologically-Based Kinetic modelling in risk assessment – reaching a whole new level in regulatory decision-making” held in Ispra, Italy, in November 2016, along with results from an international survey conducted in 2017 and recently reported activities occurring within the PBK modelling field. The discussions presented herein highlight the potential applications of next generation (NG)-PBK modelling, based on new data streams.

Comparison of ammonia emissions related to nitrogen use efficiency of livestock production in Europe
Groenestein, C.M. ; Hutchings, N.J. ; Haenel, H.D. ; Amon, B. ; Menzi, H. ; Mikkelsen, M.H. ; Misselbrook, T.H. ; Bruggen, C. van; Kupper, T. ; Webb, J. - \ 2019
Journal of Cleaner Production 211 (2019). - ISSN 0959-6526 - p. 1162 - 1170.
Ammonia emission intensity - Animal protein - Feed nitrogen - Manure management - Nitrogen use efficiency

The increasing global demand for food and the environmental effects of reactive nitrogen losses in the food production chain, increase the need for efficient use of nitrogen (N). Of N harvested in agricultural plant products, 80% is used to feed livestock. Because the largest atmospheric loss of reactive nitrogen from livestock production systems is ammonia (NH3), the focus of this paper is on N lost as NH3 during the production of animal protein. The focus of this paper is to understand the key factors explaining differences in Nitrogen Use Efficiency (NUE) of animal production among various European countries. Therefore we developed a conceptual framework to describe the NUE defined as the amount of animal-protein N per N in feed and NH3–N losses in the production of milk, beef, pork, chicken meat and eggs in The Netherlands, Switzerland, United Kingdom, Germany, Austria and Denmark. The framework describes how manure management and animal-related parameters (feed, metabolism) relate to NH3 emissions and NUE. The results showed that the animal product with the lowest NUE had the largest NH3 emissions and vice versa, which agrees with the reciprocal relationship between NUE and NH3 within the conceptual framework. Across animal products for the countries considered, about 20% of the N in feed is lost as NH3. The significant smallest proportion (12%) of NH3–N per unit of Nfeed is from chicken production. The proportions for other products are 17%, 19%, 20% and 22% for milk, pork, eggs and beef respectively. These differences were not significantly different due to the differences among countries. For all countries, NUE was lowest for beef and highest for chicken. The production of 1 kg N in beef required about 5 kg N in feed, of which 1 kg N was lost as NH3–N. For the production of 1 kg N in chicken meat, 2 kg N in feed was required and 0.2 kg was lost as NH3. The production of 1 kg N in milk required 4 kg N in feed with 0.6 kg NH3–N loss, the same as pork and eggs, but those needed 3 and 3.5 kg N in feed per kg N in product respectively. Except for beef, the differences among these European countries were mainly caused by differences in manure management practices and their emission factors, rather than by animal-related factors including feed and digestibility influencing the excreted amount of ammoniacal N (TAN). For beef, both aspects caused important differences. Based on the results, we encourage the expression of N losses as per N in feed or per N in product, in addition to per animal place, when comparing production efficiency and NUE. We consider that disaggregating emission factors into a diet/animal effect and a manure management effect would improve the basis for comparing national NH3 emission inventories.

The effect of low pH on physiology, stress status and growth performance of turbot (Psetta maxima L.) cultured in recirculating aquaculture systems
Mota, Vasco C. ; Hop, Jochem ; Sampaio, Luís A. ; Heinsbroek, Leon T.N. ; Verdegem, Marc C.J. ; Eding, Ep H. ; Verreth, Johan A.J. - \ 2018
Aquaculture Research 49 (2018)10. - ISSN 1355-557X - p. 3456 - 3467.
aquaculture - fish - NH-N - nitrification - total ammonia nitrogen (TAN)

We evaluated the effect of low pH and low and high total ammonia nitrogen (TAN) concentrations on the physiology, stress status and the growth performance of turbot in RAS. Two experiments were conducted. In Experiment 1, turbot (466 g) were grown at control (pH 7.5; TAN ~0.5 mg/L) or low pH and high TAN (pH 5.7; TAN ~50 mg/L) for 55 days. In Experiment 2, turbot (376 g) were grown at control (pH 7.5; TAN ~0.5 mg/L), low pH and low TAN (pH 5.7; TAN ~5 mg/L) or low pH and high TAN (pH 5.7; TAN ~50 mg/L) for 59 days. In Experiment 1, final body weight, feed intake and growth were significantly lower and FCR significantly higher in turbot exposed to low pH and high TAN. In Experiment 2, only growth was significantly lower in turbot exposed to treatment low pH and high TAN as compared to fish in the control treatment and low pH and low TAN. Osmoregulation and stress indicators measured were within normal levels. In conclusion, turbot grew equally well in a water pH of 7.5 or 5.7 provided a low TAN. In contrast, low pH combined with a high TAN impaired turbot performance.

Spatial variation of modelled total, dry and wet nitrogen deposition to forests at global scale
Schwede, Donna B. ; Simpson, David ; Tan, Jiani ; Fu, Joshua S. ; Dentener, Frank ; Du, Enzai ; Vries, Wim de - \ 2018
Environmental Pollution 243 (2018)B. - ISSN 0269-7491 - p. 1287 - 1301.
Dry deposition - Forest biomes - Modelling approach - Nitrogen deposition - Wet deposition

Forests are an important biome that covers about one third of the global land surface and provides important ecosystem services. Since atmospheric deposition of nitrogen (N) can have both beneficial and deleterious effects, it is important to quantify the amount of N deposition to forest ecosystems. Measurements of N deposition to the numerous forest biomes across the globe are scarce, so chemical transport models are often used to provide estimates of atmospheric N inputs to these ecosystems. We provide an overview of approaches used to calculate N deposition in commonly used chemical transport models. The Task Force on Hemispheric Transport of Air Pollution (HTAP2) study intercompared N deposition values from a number of global chemical transport models. Using a multi-model mean calculated from the HTAP2 deposition values, we map N deposition to global forests to examine spatial variations in total, dry and wet deposition. Highest total N deposition occurs in eastern and southern China, Japan, Eastern U.S. and Europe while the highest dry deposition occurs in tropical forests. The European Monitoring and Evaluation Program (EMEP) model predicts grid-average deposition, but also produces deposition by land use type allowing us to compare deposition specifically to forests with the grid-average value. We found that, for this study, differences between the grid-average and forest specific could be as much as a factor of two and up to more than a factor of five in extreme cases. This suggests that consideration should be given to using forest-specific deposition for input to ecosystem assessments such as critical loads determinations. Estimates of nitrogen deposition to global forests by global models may be a factor of 2 or more higher if the forest-specific deposition is used, compared to the grid cell average value and is on average 12% higher for all global forests.

The Dutch National Genebank (CGN)
Dooijeweert, Willem van - \ 2018
Nitrate improves ammonia incorporation into rumen microbial protein in lactating dairy cows fed a low-protein diet
Wang, Rong ; Wang, Min ; Ungerfeld, Emilio M. ; Zhang, Xiu Min ; Long, Dong Lei ; Mao, Hong Xiang ; Deng, Jin Ping ; Bannink, André ; Tan, Zhi Liang - \ 2018
Journal of Dairy Science 101 (2018)11. - ISSN 0022-0302 - p. 9789 - 9799.
dissolved hydrogen - microbial protein - nitrate - rumen fermentation

Generation of ammonia from nitrate reduction is slower compared with urea hydrolysis and may be more efficiently incorporated into ruminal microbial protein. We hypothesized that nitrate supplementation could increase ammonia incorporation into microbial protein in the rumen compared with urea supplementation of a low-protein diet fed to lactating dairy cows. Eight multiparous Chinese Holstein dairy cows were used in a crossover design to investigate the effect of nitrate or an isonitrogenous urea inclusion in the basal low-protein diet on rumen fermentation, milk yield, and ruminal microbial community in dairy cows fed a low-protein diet in comparison with an isonitrogenous urea control. Eight lactating cows were blocked in 4 pairs according to days in milk, parity, and milk yield and allocated to urea (7.0 g urea/kg of dry matter of basal diet) or nitrate (14.6 g of NO3 /kg of dry matter of basal diet, supplemented as sodium nitrate) treatments, which were formulated on 75% of metabolizable protein requirements. Nitrate supplementation decreased ammonia concentration in the rumen liquids (−33.1%) and plasma (−30.6%) as well as methane emissions (−15.0%) and increased dissolved hydrogen concentration (102%), microbial N (22.8%), propionate molar percentage, milk yield, and 16S rRNA gene copies of Selenomonas ruminantium. Ruminal dissolved hydrogen was positively correlated with the molar proportion of propionate (r = 0.57), and negatively correlated with acetate-to-propionate ratio (r = −0.57) and estimated net metabolic hydrogen production relative to total VFA produced (r = −0.58). Nitrate reduction to ammonia redirected metabolic hydrogen away from methanogenesis, enhanced ammonia incorporation into rumen microbial protein, and shifted fermentation from acetate to propionate, along with increasing S. ruminantium 16S rRNA gene copies, likely leading to the increased milk yield.

Effects of Stigeoclonium nanum, a freshwater periphytic microalga on water quality in a small-scale recirculating aquaculture system
Mohamed Ramli, Norulhuda ; Yusoff, Fatimah M. ; Giatsis, Christos ; Tan, Geok Yuan A. ; Verreth, Johan A.J. ; Verdegem, Marc C.J. - \ 2018
Aquaculture Research 49 (2018)11. - ISSN 1355-557X - p. 3529 - 3540.
ammonia - bacterial community - microalgae - nitrate - recirculating aquaculture system - Stigeoclonium nanum - water quality

Recirculating aquaculture systems (RAS) are becoming important for aquaculture due to land and water supply limitations and due to their low environmental impact. Bacteria are important in RAS as their role in nutrient recycling has been the main mechanism for waste removal in these systems. Besides bacteria, the presence of microalgae can benefit the water quality through the absorption of inorganic nitrogen (ammonium and nitrate) and phosphorus from the water. However, reports on the inclusion of microalgae in RAS are very scarce. The objective of this study was to determine the effect of microalgae on water quality (total ammonia nitrogen, nitrite, nitrate and phosphate) and bacterial composition in a freshwater small-scale RAS. A periphytic microalga, Stigeoclonium nanum, was used in this study. A rapid fingerprint analysis, denaturing gradient gel electrophoresis (DGGE), was used to determine the bacterial community composition in the water. The results showed that ammonia concentrations were not significantly different (p > 0.05) between RAS with microalgae (RAS+A) and RAS without microalgae (RAS-A). However, nitrite, nitrate and phosphate were significantly lower in the RAS+A than the RAS-A (p < 0.05). Pielou's evenness and Shannon diversity index of bacterial community between the treatments were not different (p > 0.05); however, the bacterial composition between the treatments was significantly different (p < 0.05).

Consumer acceptance of insects as food : Integrating psychological and socio-cultural perspectives
Tan, Hui Shan Grace ; House, Jonas - \ 2018
In: Edible Insects in Sustainable Food Systems / Halloran, Afton, Flore, Roberto, Vantomme, Paul, Roos, Nanna, Springer International Publishing - ISBN 9783319740102 - p. 375 - 386.

Although interest in the use of insects as food is growing in Europe and the US (the "West"), Western insect consumption remains far from widespread. Western resistance to entomophagy is often contrasted with the favourable position of edible insects in other regions, but little scholarship thus far has engaged with the question of why this difference exists. Drawing mainly on two qualitative studies, we compare the factors affecting insect consumption in contexts where it is both established (northeast Thailand) and where it is not (the Netherlands). We argue that the integration of different disciplinary perspectives elucidates the complexity of consumer acceptance, which goes beyond simple "willingness to eat" insects. Our research shows that the positioning of insects as an appreciated, regularly consumed food is the result of the intersection of a broad range of psychological, socio-cultural, practical and contextual factors. In addition to the commonly discussed psychological factors, regular insect consumption is determined by previous experience, culinary knowledge, wider cultural associations, established routines of food provisioning and eating, and the availability, price, form and taste of products. We suggest both demand-side factors (changing consumer perceptions) and supply-side factors (creating tasty, usable, distinctive and accessible products) are equally important to gaining consumer acceptance. We also emphasise that initial motivations to eat insects and repeated consumption are different things, and that there is a need to distinguish between the two in future scholarly and commercial efforts.

CD-MUSIC-EDL modeling of Pb2+ adsorption on birnessites : Role of vacant and edge sites
Zhao, Wei ; Tan, Wenfeng ; Wang, Mingxia ; Xiong, Juan ; Liu, Fan ; Weng, Liping ; Koopal, Luuk K. - \ 2018
Environmental Science and Technology 52 (2018)18. - ISSN 0013-936X - p. 10522 - 10531.
adsorption - Birnessite - CD-MUSIC Modeling - Electrical double layer model - External surface - Interlayer space - Manganese oxide - Mn average oxidation state - Pb - Rietveld refinement

The surface complexation modeling of metal adsorption to birnessites is in its infancy compared to the charge-distribution multi-site ion complexation (CD-MUSIC) models for iron/aluminum (hydr)oxides. Therefore, using X-ray diffraction with Rietveld refinement to obtain the reactive sites and their densities, a CD-MUSIC model combined with a Stern-Gouy-Chapman electrical double layer (EDL) model for the external surface and a Donnan model for the interlayer surface is developed for birnessites with different Mn average oxidation state (MnAOS). Proton affinity constants and the charge distributions of Pb surface complexes were calculated a priory. By fitting Pb adsorption data to the model the obtained equilibrium constants (logKPb) of Pb complexes were 6.9-10.9 for the double-corner-sharing and double-edge-sharing Pb2+ complexes on the edge sites and 2.2-6.5 for the triple-corner-sharing Pb2+ complex on the vacancies. The larger logKPb value was obtained for higher MnAOS. Speciation calculations showed that with increasing MnAOS from 3.67 to 3.92 the interlayer surface contribution to the total Pb2+ adsorption increased from 43.2% to 48.6%, and the vacancy contribution increased from 43.9% to 54.7%. The vacancy contribution from interlayer surface was predominant. The present CD-MUSIC-EDL model contributes to understand better the difference in metal adsorption mechanism between birnessite and iron/aluminum (hydr)oxides.

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