No adverse effect of genetically modified antifungal wheat on decomposition dynamics and the soil fauna community - a field study

The cultivation of genetically modified (GM) plants has raised several environmental concerns. One of these concerns regards non-target soil fauna organisms, which play an important role in the decomposition of organic matter and hence are largely exposed to GM plant residues. Soil fauna may be directly affected by transgene products or indirectly by pleiotropic effects such as a modified plant metabolism. Thus, ecosystem services and functioning might be affected negatively. In a litterbag experiment in the field we analysed the decomposition process and the soil fauna community involved. Therefore, we used four experimental GM wheat varieties, two with a race-specific antifungal resistance against powdery mildew (Pm3b) and two with an unspecific antifungal resistance based on the expression of chitinase and glucanase. We compared them with two non-GM isolines and six conventional cereal varieties. To elucidate the mechanisms that cause differences in plant decomposition, structural plant components (i.e. C:N ratio, lignin, cellulose, hemicellulose) were examined and soil properties, temperature and precipitation were monitored. The most frequent taxa extracted from decaying plant material were mites (Cryptostigmata, Gamasina and Uropodina), springtails (Isotomidae), annelids (Enchytraeidae) and Diptera (Cecidomyiidae larvae). Despite a single significant transgenic/month interaction for Cecidomyiidae larvae, which is probably random, we detected no impact of the GM wheat on the soil fauna community. However, soil fauna differences among conventional cereal varieties were more pronounced than between GM and non-GM wheat. While leaf residue decomposition in GM and non-GM wheat was similar, differences among conventional cereals were evident. Furthermore, sampling date and location were found to greatly influence soil fauna community and decomposition processes. The results give no indication of ecologically relevant adverse effects of antifungal GM wheat on the composition and the activity of the soil fauna community.

Interethnic Interaction Dynamics in the Russian Federation

The collapse of the Soviet Union at the beginning of the 1990s also meant the end of the idea of a common soviet identity incarnated in the "soviet man" and the new "historic community of the soviet people". While this idea still lives on in the generations of the 1920s to 1940s, the younger generations tend to prefer identification with family, profession, ethnic group or religion. Ms. Alexakhina set out to investigate different interethnic interaction strategies in the multi-ethnic context of the Russian Federation, with an emphasis on analysing the role of cultural and ethno-demographic characteristics of minority ethnic groups. It aimed to identify those specific patterns of interaction dynamics that have emerged in response to the political and economic transformation at present under way. The basic supposition was that the size and growth of an ethnic population are defined not only by demographic features such as fertility, mortality and net migration, but are also dependent on processes interethnic interaction and ethnic transition. The central hypothesis of the project was that the multi-ethnic and multi-cultural composition of Russia is apparently manifesting itself in the ethnic minority groups in various forms, but particularly in the form of ethnic revival and/or assimilation. The results of these complex phenomena are manifested as changes in ethnic attachments (national re-identification and language behaviour (multi-lingualism, language transition and loss of the mother tongue). The stress of the political and economic crisis has stimulated significant changes in ethnographic, social and cultural characteristics of inter-ethnic dynamics such as the rate of national re-identification, language behaviour, migration activity and the spread of mixed marriages, among both those minorities with a long history of settlement in Russia and those that were annexed during the soviet period. Patterns of language behaviour and the spread of mixed marriages were taken as the main indicators of the directions of interethnic interaction described as assimilation, ethnic revival and cultural pluralism. The first stage of the research involved a statistical analysis of census data from 1959 to 1994 in order to analyse the changing demographic composition of the largest ethnic groups of the Russian Federation. Until 1989 interethnic interaction in soviet society was distinguished by the process of russification but the political and economic transformation has stimulated the process of ethnic revival, leading to an apparent fall in the size of the Russian population due to ethnic re-identification by members of other ethnic groups who had previously identified themselves as Russian. Cross-classification of nationalities by demographic, social and cultural indicators has shown that the most important determinants of the nature of interethnic interaction are cultural factors such as religion and language affiliation. The analysis of the dynamics of language shift through the study of bilingualism and the domains of language usage for different demographic groups revealed a strong correlation between recognition of Russian as a mother tongue among some non-Russian ethnic groups and the declining size of these groups. The main conclusion from this macro-analysis of census data was the hypothesis of the growing importance of social and political factors upon ethnic succession, that ethnic identity is no longer a stable characteristic but has become dynamic in nature. In order to verify this hypothesis Ms. Alexakhina conducted a survey in four regions showing different patterns of interethnic interaction: the Karelian Republic, Buryatiya, the Nenezkii Autonomous Region and Tatarstan. These represented the west, east, north and south of the Russian Federation. Samples for the survey were prepared on the basis of census lists so as to exclude mono-Russian families in favour of mixed and ethnic-minority families. The survey confirmed the significant growth in the importance of ethnic affiliation in the everyday lives of people in the Federation following the de-centralisation of the political and economic spheres. Language was shown to be a key symbol of the consciousness of national distinction, confirmed by the fact that the process of russification has been reversed by the active mastering of the languages of titular nationalities. The results also confirmed that individual ethnic identity has ceased to be a fixed personal characteristic of one's cultural and genetic belonging, and people's social adaptation to the current political, social and economic conditions is also demonstrated in changes in individual ethnic self-identification. In general terms, the dynamic nature of national identity means that ethnic identity is at present acquiring the special features of overall social identity, for which the frequent change of priorities is an inherent feature of a person's life cycle. These are mainly linked with a multi-ethnic environment and high individual social mobility. From her results Ms. Alexakhina concludes that the development of national languages and multi-lingualism, together with the preservation of Russian as a state language, seems to be the most promising path to peaceful coexistence and the development of the national cultures of different ethnic groups within the Russian Federation.

The Dynamics of the Policies of Ethnic Cleansing in Silesia in the Nineteenth and Twentieth Centuries

Through studying German, Polish and Czech publications on Silesia, Mr. Kamusella found that most of them, instead of trying to objectively analyse the past, are devoted to proving some essential "Germanness", "Polishness" or "Czechness" of this region. He believes that the terminology and thought-patterns of nationalist ideology are so deeply entrenched in the minds of researchers that they do not consider themselves nationalist. However, he notes that, due to the spread of the results of the latest studies on ethnicity/nationalism (by Gellner, Hobsbawm, Smith, Erikson Buillig, amongst others), German publications on Silesia have become quite objective since the 1980s, and the same process (impeded by under funding) has been taking place in Poland and the Czech Republic since 1989. His own research totals some 500 pages, in English, presented on disc. So what are the traps into which historians have been inclined to fall? There is a tendency for them to treat Silesia as an entity which has existed forever, though Mr. Kamusella points out that it emerged as a region only at the beginning of the 11th century. These same historians speak of Poles, Czechs and Germans in Silesia, though Mr. Kamusella found that before the mid-19th century, identification was with an inhabitant's local area, religion or dynasty. In fact, a German national identity started to be forged in Prussian Silesia only during the Liberation War against Napoleon (1813-1815). It was concretised in 1861 in the form of the first Prussian census, when the language a citizen spoke was equated with his/her nationality. A similar census was carried out in Austrian Silesia only in 1881. The censuses forced the Silesians to choose their nationality despite their multiethnic multicultural identities. It was the active promotion of a German identity in Prussian Silesia, and Vienna's uneasy acceptance of the national identities in Austrian Silesia which stimulated the development of Polish national, Moravian ethnic and Upper Silesian ethnic regional identities in Upper Silesia, and Polish national, Czech national, Moravian ethnic and Silesian ethnic identities in Austrian Silesia. While traditional historians speak of the "nationalist struggle" as though it were a permanent characteristic of Silesia, Mr. Kamusella points out that such a struggle only developed in earnest after 1918. What is more, he shows how it has been conveniently forgotten that, besides the national players, there were also significant ethnic movements of Moravians, Upper Silesians, Silesians and the tutejsi (i.e. those who still chose to identify with their locality). At this point Mr. Kamusella moves into the area of linguistics. While traditionally historians have spoken of the conflicts between the three national languages (German, Polish and Czech), Mr Kamusella reminds us that the standardised forms of these languages, which we choose to dub "national", were developed only in the mid-18th century, after 1869 (when Polish became the official language in Galicia), and after the 1870s (when Czech became the official language in Bohemia). As for standard German, it was only widely promoted in Silesia from the mid 19th century onwards. In fact, the majority of the population of Prussian Upper Silesia and Austrian Silesia were bi- or even multilingual. What is more, the "Polish" and "Czech" Silesians spoke were not the standard languages we know today, but a continuum of West-Slavic dialects in the countryside and a continuum of West-Slavic/German creoles in the urbanised areas. Such was the linguistic confusion that, from time to time, some ethnic/regional and Church activists strove to create a distinctive Upper Silesian/Silesian language on the basis of these dialects/creoles, but their efforts were thwarted by the staunch promotion of standard German, and after 1918, of standard Polish and Czech. Still on the subject of language, Mr. Kamusella draws attention to a problem around the issue of place names and personal names. Polish historians use current Polish versions of the Silesian place names, Czechs use current Polish/Czech versions of the place names, and Germans use the German versions which were in use in Silesia up to 1945. Mr. Kamusella attempted to avoid this, as he sees it, nationalist tendency, by using an appropriate version of a place name for a given period and providing its modern counterpart in parentheses. In the case of modern place names he gives the German version in parentheses. As for the name of historical figures, he strove to use the name entered on the birth certificate of the person involved, and by doing so avoid such confusion as, for instance, surrounds the Austrian Silesian pastor L.J. Sherschnik, who in German became Scherschnick, in Polish, Szersznik, and in Czech, Sersnik. Indeed, the prospective Silesian scholar should, Mr. Kamusella suggests, as well as the three languages directly involved in the area itself, know English and French, since many documents and books on the subject have been published in these languages, and even Latin, when dealing in depth with the period before the mid-19th century. Mr. Kamusella divides the policies of ethnic cleansing into two categories. The first he classifies as soft, meaning that policy is confined to the educational system, army, civil service and the church, and the aim is that everyone learn the language of the dominant group. The second is the group of hard policies, which amount to what is popularly labelled as ethnic cleansing. This category of policy aims at the total assimilation and/or physical liquidation of the non-dominant groups non-congruent with the ideal of homogeneity of a given nation-state. Mr. Kamusella found that soft policies were consciously and systematically employed by Prussia/Germany in Prussian Silesia from the 1860s to 1918, whereas in Austrian Silesia, Vienna quite inconsistently dabbled in them from the 1880s to 1917. In the inter-war period, the emergence of the nation-states of Poland and Czechoslovakia led to full employment of the soft policies and partial employment of the hard ones (curbed by the League of Nations minorities protection system) in Czechoslovakian Silesia, German Upper Silesia and the Polish parts of Upper and Austrian Silesia. In 1939-1945, Berlin started consistently using all the "hard" methods to homogenise Polish and Czechoslovakian Silesia which fell, in their entirety, within the Reich's borders. After World War II Czechoslovakia regained its prewar part of Silesia while Poland was given its prewar section plus almost the whole of the prewar German province. Subsequently, with the active involvement and support of the Soviet Union, Warsaw and Prague expelled the majority of Germans from Silesia in 1945-1948 (there were also instances of the Poles expelling Upper Silesian Czechs/Moravians, and of the Czechs expelling Czech Silesian Poles/pro-Polish Silesians). During the period of communist rule, the same two countries carried out a thorough Polonisation and Czechisation of Silesia, submerging this region into a new, non-historically based administrative division. Democratisation in the wake of the fall of communism, and a gradual retreat from the nationalist ideal of the homogeneous nation-state with a view to possible membership of the European Union, caused the abolition of the "hard" policies and phasing out of the "soft" ones. Consequently, limited revivals of various ethnic/national minorities have been observed in Czech and Polish Silesia, whereas Silesian regionalism has become popular in the westernmost part of Silesia which remained part of Germany. Mr. Kamusella believes it is possible that, with the overcoming of the nation-state discourse in European politics, when the expression of multiethnicity and multilingualism has become the cause of the day in Silesia, regionalism will hold sway in this region, uniting its ethnically/nationally variegated population in accordance with the principle of subsidiarity championed by the European Union.

A novel computer simulation method for simulating the multiscale transduction dynamics of signal proteins

Signal proteins are able to adapt their response to a change in the environment, governing in this way a broad variety of important cellular processes in living systems. While conventional molecular-dynamics (MD) techniques can be used to explore the early signaling pathway of these protein systems at atomistic resolution, the high computational costs limit their usefulness for the elucidation of the multiscale transduction dynamics of most signaling processes, occurring on experimental timescales. To cope with the problem, we present in this paper a novel multiscale-modeling method, based on a combination of the kinetic Monte-Carlo- and MD-technique, and demonstrate its suitability for investigating the signaling behavior of the photoswitch light-oxygen-voltage-2-Jα domain from Avena Sativa (AsLOV2-Jα) and an AsLOV2-Jα-regulated photoactivable Rac1-GTPase (PA-Rac1), recently employed to control the motility of cancer cells through light stimulus. More specifically, we show that their signaling pathways begin with a residual re-arrangement and subsequent H-bond formation of amino acids near to the flavin-mononucleotide chromophore, causing a coupling between β-strands and subsequent detachment of a peripheral α-helix from the AsLOV2-domain. In the case of the PA-Rac1 system we find that this latter process induces the release of the AsLOV2-inhibitor from the switchII-activation site of the GTPase, enabling signal activation through effector-protein binding. These applications demonstrate that our approach reliably reproduces the signaling pathways of complex signal proteins, ranging from nanoseconds up to seconds at affordable computational costs.

Towards dynamics in flood risk assessment

As a consequence of flood impacts, communities inhabiting mountain areas are increasingly affected by considerable damage to infrastructure and property. The design of effective flood risk mitigation strategies and their subsequent implementation is crucial for a sustainable development in mountain areas. The assessment of the dynamic evolution of flood risk is the pillar of any subsequent planning process that is targeted at a reduction of the expected adverse consequences of the hazard impact. Given these premises, firstly, a comprehensive method to derive flood hazard process scenarios for well-defined areas at risk is presented. Secondly, conceptualisations of a static and dynamic flood risk assessment are provided. These are based on formal schemes to compute the risk mitigation performance of devised mitigation strategies within the framework of economic cost-benefit analysis. In this context, techniques suitable to quantify the expected losses induced by the identified flood impacts are provided.

Simulating the impact of four control strategies on the population dynamics of Neospora caninum infection in Swiss dairy cattle

A dynamic deterministic simulation model was developed to assess the impact of different putative control strategies on the seroprevalence of Neospora caninum in female Swiss dairy cattle. The model structure comprised compartments of "susceptible" and "infected" animals (SI-model) and the cattle population was divided into 12 age classes. A reference model (Model 1) was developed to simulate the current (status quo) situation (present seroprevalence in Switzerland 12%), taking into account available demographic and seroprevalence data of Switzerland. Model 1 was modified to represent four putative control strategies: testing and culling of seropositive animals (Model 2), discontinued breeding with offspring from seropositive cows (Model 3), chemotherapeutic treatment of calves from seropositive cows (Model 4), and vaccination of susceptible and infected animals (Model 5). Models 2-4 considered different sub-scenarios with regard to the frequency of diagnostic testing. Multivariable Monte Carlo sensitivity analysis was used to assess the impact of uncertainty in input parameters. A policy of annual testing and culling of all seropositive cattle in the population reduced the seroprevalence effectively and rapidly from 12% to <1% in the first year of simulation. The control strategies with discontinued breeding with offspring from all seropositive cows, chemotherapy of calves and vaccination of all cattle reduced the prevalence more slowly than culling but were still very effective (reduction of prevalence below 2% within 11, 23 and 3 years of simulation, respectively). However, sensitivity analyses revealed that the effectiveness of these strategies depended strongly on the quality of the input parameters used, such as the horizontal and vertical transmission factors, the sensitivity of the diagnostic test and the efficacy of medication and vaccination. Finally, all models confirmed that it was not possible to completely eradicate N. caninum as long as the horizontal transmission process was not interrupted.

Structural response and dynamics of fluid-structure-control interaction in wind turbine blades

Reducing the uncertainties related to blade dynamics by the improvement of the quality of numerical simulations of the fluid structure interaction process is a key for a breakthrough in wind-turbine technology. A fundamental step in that direction is the implementation of aeroelastic models capable of capturing the complex features of innovative prototype blades, so they can be tested at realistic full-scale conditions with a reasonable computational cost. We make use of a code based on a combination of two advanced numerical models implemented in a parallel HPC supercomputer platform: First, a model of the structural response of heterogeneous composite blades, based on a variation of the dimensional reduction technique proposed by Hodges and Yu. This technique has the capacity of reducing the geometrical complexity of the blade section into a stiffness matrix for an equivalent beam. The reduced 1-D strain energy is equivalent to the actual 3-D strain energy in an asymptotic sense, allowing accurate modeling of the blade structure as a 1-D finite-element problem. This substantially reduces the computational effort required to model the structural dynamics at each time step. Second, a novel aerodynamic model based on an advanced implementation of the BEM(Blade ElementMomentum) Theory; where all velocities and forces are re-projected through orthogonal matrices into the instantaneous deformed configuration to fully include the effects of large displacements and rotation of the airfoil sections into the computation of aerodynamic forces. This allows the aerodynamic model to take into account the effects of the complex flexo-torsional deformation that can be captured by the more sophisticated structural model mentioned above. In this thesis we have successfully developed a powerful computational tool for the aeroelastic analysis of wind-turbine blades. Due to the particular features mentioned above in terms of a full representation of the combined modes of deformation of the blade as a complex structural part and their effects on the aerodynamic loads, it constitutes a substantial advancement ahead the state-of-the-art aeroelastic models currently available, like the FAST-Aerodyn suite. In this thesis, we also include the results of several experiments on the NREL-5MW blade, which is widely accepted today as a benchmark blade, together with some modifications intended to explore the capacities of the new code in terms of capturing features on blade-dynamic behavior, which are normally overlooked by the existing aeroelastic models.

A Nonstationary Space-Time Gaussian Process Model for Partially Converged Simulations

In the context of expensive numerical experiments, a promising solution for alleviating the computational costs consists of using partially converged simulations instead of exact solutions. The gain in computational time is at the price of precision in the response. This work addresses the issue of fitting a Gaussian process model to partially converged simulation data for further use in prediction. The main challenge consists of the adequate approximation of the error due to partial convergence, which is correlated in both design variables and time directions. Here, we propose fitting a Gaussian process in the joint space of design parameters and computational time. The model is constructed by building a nonstationary covariance kernel that reflects accurately the actual structure of the error. Practical solutions are proposed for solving parameter estimation issues associated with the proposed model. The method is applied to a computational fluid dynamics test case and shows significant improvement in prediction compared to a classical kriging model.

Dynamics of vessel wall changes following the implantation of the Absorb everolimus-eluting bioresorbable vascular scaffold: a multi-imaging modality study at 6, 12, 24 and 36 months

Aims: To assess observations with multimodality imaging of the Absorb bioresorbable everolimus-eluting vascular scaffold performed in two consecutive cohorts of patients who were serially investigated either at 6 and 24 months or at 12 and 36 months. Methods and results: In the ABSORB multicentre single-arm trial, 45 patients (cohort B1) and 56 patients (cohort B2) underwent serial invasive imaging, specifically quantitative coronary angiography (QCA), intravascular ultrasound (IVUS), radiofrequency backscattering (IVUS-VH) and optical coherence tomography (OCT). Between one and three years, late luminal loss remained unchanged (6 months: 0.19 mm, 1 year: 0.27 mm, 2 years: 0.27 mm, 3 years: 0.29 mm) and the in-segment angiographic restenosis rate for the entire cohort B (n=101) at three years was 6%. On IVUS, mean lumen, scaffold, plaque and vessel area showed enlargement up to two years. Mean lumen and scaffold area remained stable between two and three years whereas significant reduction in plaque behind the struts occurred with a trend toward adaptive restrictive remodelling of EEM. Hyperechogenicity of the vessel wall, a surrogate of the bioresorption process, decreased from 23.1% to 10.4% with a reduction of radiofrequency backscattering for dense calcium and necrotic core. At three years, the count of strut cores detected on OCT increased significantly, probably reflecting the dismantling of the scaffold; 98% of struts were covered. In the entire cohort B (n=101), the three-year major adverse cardiac event rate was 10.0% without any scaffold thrombosis. Conclusions: The current investigation demonstrated the dynamics of vessel wall changes after implantation of a bioresorbable scaffold, resulting at three years in stable luminal dimensions, a low restenosis rate and a low clinical major adverse cardiac events rate.

The role of zinc dynamics in growth hormone secretion

Human growth hormone (GH) causes a variety of physiological and metabolic effects in humans and plays a pivotal role in postnatal growth. In somatotroph cells of the anterior pituitary, GH is stored in concentrated forms in secretory granules to be rapidly released upon GH-releasing hormone stimulation. During the process of secretory granule biogenesis, self-association of GH occurs in the compartments of the early secretory pathway (endoplasmic reticulum and Golgi complex). Since this process is greatly facilitated by the presence of zinc ions, it is of importance to understand the potential role of zinc transporters that participate in the fine-tuning of zinc homeostasis and dynamics, particularly in the early secretory pathway. Thus, the role of zinc transporters in supplying the secretory pathway with the sufficient amount of zinc required for the biogenesis of GH-containing secretory granules is essential for normal secretion. This report, illustrated by a clinical case report on transient neonatal zinc deficiency, focuses on the role of zinc in GH storage in the secretory granules and highlights the role of specific zinc transporters in the early secretory pathway.

Glacial–interglacial dynamics of Antarctic firn columns: comparison between simulations and ice core air-δ15N measurements

Correct estimation of the firn lock-in depth is essential for correctly linking gas and ice chronologies in ice core studies. Here, two approaches to constrain the firn depth evolution in Antarctica are presented over the last deglaciation: outputs of a firn densification model, and measurements of δ15N of N2 in air trapped in ice core, assuming that δ15N is only affected by gravitational fractionation in the firn column. Since the firn densification process is largely governed by surface temperature and accumulation rate, we have investigated four ice cores drilled in coastal (Berkner Island, BI, and James Ross Island, JRI) and semi-coastal (TALDICE and EPICA Dronning Maud Land, EDML) Antarctic regions. Combined with available ice core air-δ15N measurements from the EPICA Dome C (EDC) site, the studied regions encompass a large range of surface accumulation rates and temperature conditions. Our δ15N profiles reveal a heterogeneous response of the firn structure to glacial–interglacial climatic changes. While firn densification simulations correctly predict TALDICE δ15N variations, they systematically fail to capture the large millennial-scale δ15N variations measured at BI and the δ15N glacial levels measured at JRI and EDML – a mismatch previously reported for central East Antarctic ice cores. New constraints of the EDML gas–ice depth offset during the Laschamp event (~41 ka) and the last deglaciation do not favour the hypothesis of a large convective zone within the firn as the explanation of the glacial firn model–δ15N data mismatch for this site. While we could not conduct an in-depth study of the influence of impurities in snow for firnification from the existing datasets, our detailed comparison between the δ15N profiles and firn model simulations under different temperature and accumulation rate scenarios suggests that the role of accumulation rate may have been underestimated in the current description of firnification models.

Transient simulations of the carbon and nitrogen dynamics in northern peatlands: from the Last Glacial Maximum to the 21st century

The development of northern high-latitude peatlands played an important role in the carbon (C) balance of the land biosphere since the Last Glacial Maximum (LGM). At present, carbon storage in northern peatlands is substantial and estimated to be 500 ± 100 Pg C (1 Pg C = 1015 g C). Here, we develop and apply a peatland module embedded in a dynamic global vegetation and land surface process model (LPX-Bern 1.0). The peatland module features a dynamic nitrogen cycle, a dynamic C transfer between peatland acrotelm (upper oxic layer) and catotelm (deep anoxic layer), hydrology- and temperature-dependent respiration rates, and peatland specific plant functional types. Nitrogen limitation down-regulates average modern net primary productivity over peatlands by about half. Decadal acrotelm-to-catotelm C fluxes vary between −20 and +50 g C m−2 yr−1 over the Holocene. Key model parameters are calibrated with reconstructed peat accumulation rates from peat-core data. The model reproduces the major features of the peat core data and of the observation-based modern circumpolar soil carbon distribution. Results from a set of simulations for possible evolutions of northern peat development and areal extent show that soil C stocks in modern peatlands increased by 365–550 Pg C since the LGM, of which 175–272 Pg C accumulated between 11 and 5 kyr BP. Furthermore, our simulations suggest a persistent C sequestration rate of 35–50 Pg C per 1000 yr in present-day peatlands under current climate conditions, and that this C sink could either sustain or turn towards a source by 2100 AD depending on climate trajectories as projected for different representative greenhouse gas concentration pathways.

Methane emissions from floodplains in the Amazon Basin: challenges in developing a process-based model for global applications

Tropical wetlands are estimated to represent about 50% of the natural wetland methane (CH4) emissions and explain a large fraction of the observed CH4 variability on timescales ranging from glacial–interglacial cycles to the currently observed year-to-year variability. Despite their importance, however, tropical wetlands are poorly represented in global models aiming to predict global CH4 emissions. This publication documents a first step in the development of a process-based model of CH4 emissions from tropical floodplains for global applications. For this purpose, the LPX-Bern Dynamic Global Vegetation Model (LPX hereafter) was slightly modified to represent floodplain hydrology, vegetation and associated CH4 emissions. The extent of tropical floodplains was prescribed using output from the spatially explicit hydrology model PCR-GLOBWB. We introduced new plant functional types (PFTs) that explicitly represent floodplain vegetation. The PFT parameterizations were evaluated against available remote-sensing data sets (GLC2000 land cover and MODIS Net Primary Productivity). Simulated CH4 flux densities were evaluated against field observations and regional flux inventories. Simulated CH4 emissions at Amazon Basin scale were compared to model simulations performed in the WETCHIMP intercomparison project. We found that LPX reproduces the average magnitude of observed net CH4 flux densities for the Amazon Basin. However, the model does not reproduce the variability between sites or between years within a site. Unfortunately, site information is too limited to attest or disprove some model features. At the Amazon Basin scale, our results underline the large uncertainty in the magnitude of wetland CH4 emissions. Sensitivity analyses gave insights into the main drivers of floodplain CH4 emission and their associated uncertainties. In particular, uncertainties in floodplain extent (i.e., difference between GLC2000 and PCR-GLOBWB output) modulate the simulated emissions by a factor of about 2. Our best estimates, using PCR-GLOBWB in combination with GLC2000, lead to simulated Amazon-integrated emissions of 44.4 ± 4.8 Tg yr−1. Additionally, the LPX emissions are highly sensitive to vegetation distribution. Two simulations with the same mean PFT cover, but different spatial distributions of grasslands within the basin, modulated emissions by about 20%. Correcting the LPX-simulated NPP using MODIS reduces the Amazon emissions by 11.3%. Finally, due to an intrinsic limitation of LPX to account for seasonality in floodplain extent, the model failed to reproduce the full dynamics in CH4 emissions but we proposed solutions to this issue. The interannual variability (IAV) of the emissions increases by 90% if the IAV in floodplain extent is accounted for, but still remains lower than in most of the WETCHIMP models. While our model includes more mechanisms specific to tropical floodplains, we were unable to reduce the uncertainty in the magnitude of wetland CH4 emissions of the Amazon Basin. Our results helped identify and prioritize directions towards more accurate estimates of tropical CH4 emissions, and they stress the need for more research to constrain floodplain CH4 emissions and their temporal variability, even before including other fundamental mechanisms such as floating macrophytes or lateral water fluxes.