Governing cruise tourism at Bonaire: a networks and flows approach
Bets, L.K.J. van; Lamers, M.A.J. ; Tatenhove, J.P.M. van - \ 2017
Mobilities 12 (2017)5. - ISSN 1745-0101 - p. 778 - 793.
cruise tourism - marine community - networks - flows - environmental governance - Bonaire - small island developing state
Conceptual approaches to thoroughly study governance of cruise tourism are lacking in the literature. Relying on Castells’ network society, we analyze how two interconnected flows of cruise ships and passengers are governed by a marine community of users and policy makers. Bonaire is used as a case study. Research shows that the transnational cruise ship flow increasingly determines the local passenger flow at Bonaire. Therefore, the marine community increasingly connects with and adapts to the requirements of the transnational cruise network. Moreover, unequal power relations between cruise networks and flows prioritize the economy over the environment at Bonaire.
From farm scale synergies to village scale trade-offs: Cereal crop residues use in an agro-pastoral system of the Sudanian zone of Burkina Faso
Andrieu, N. ; Vayssières, J. ; Corbeels, M. ; Blanchard, M. ; Vall, E. ; Tittonell, P.A. - \ 2015
Agricultural Systems 134 (2015). - ISSN 0308-521X - p. 84 - 96.
west-african savanna - sub-saharan africa - livestock systems - conservation agriculture - fertility management - phosphorus budget - soil fertility - spatial carbon - nitrogen - flows
Traditionally, cereal crop harvest residues are communally grazed by the ruminant herds of villagers and transhumant pastoralists in the agro-pastoral systems which predominate in the savannah zone of West Africa. We analysed the impact of the private use of crop residues by individual farmers on crop and livestock productivity at three scales: the field, farm, and village. We collected data in the village of Koumbia, located in the Sudanian region of Burkina Faso. Three types of farmers were identified: resource-poor farmers, predominantly livestock farmers, and resource-rich farmers. The trade-offs between different uses and users of cereal crop residues at the three scales were analysed through field surveys and a simple model of biomass flows. We considered current communal use practices and two alternative scenarios of private cereal crop residue use: (i) for composting (fertility scenario) and (ii) as fodder (fodder scenario). Our analysis of current practices confirmed that farmers left around 80% of cereal crop residues on their fields. Soil fertility for cereal production therefore could be improved through crop residue management at the farm scale. We also found that communal grazing benefited farmers with high numbers of livestock. Maize grain production at the farm scale was improved in both of the simulated scenarios. Yet these scenarios had a negative impact on fodder self-sufficiency at the village scale, and on the N balance of the savannah-derived rangelands. The negative impact was greater in the fertility scenario than the fodder stock scenario. Increasing cereal productivity at the farm scale cannot be achieved without considering the trade-offs involved at the village scale. Changes in practices will require negotiations between the different types of farmers involved. Participatory innovation platforms with discussion support tools like the model presented in our study can facilitate such negotiations.
On climate change skepticism and denial in tourism
Hall, C.M. ; Amelung, B. ; Cohen, S. ; Eijgelaar, E. ; Gössling, S. ; Higham, J. ; Leemans, R. ; Peeters, P. ; Ram, Y. ; Scott, D. - \ 2015
Journal of Sustainable Tourism 23 (2015)1. - ISSN 0966-9582 - p. 4 - 25.
environmental kuznets curve - sustainable tourism - international tourism - scientific consensus - temperature-changes - economic-growth - science - reanalysis - policy - flows
The period leading to and immediately after the release of the IPCC’s fifth series of climate change assessments saw substantial efforts by climate change denial interests to portray anthropogenic climate change (ACC) as either unproven theory or a negligible contribution to natural climate variability, including the relationship between tourism and climate change. This paper responds to those claims by stressing that the extent of scientific consensus suggests that human-induced warming of the climate system is unequivocal. Second, it responds in the context of tourism research and ACC, highlighting tourism’s significant contribution to greenhouse gas emissions, as well as climate change’s potential impacts on tourism at different scales. The paper exposes the tactics used in ACC denial papers to question climate change science by referring to non-peer-reviewed literature, outlier studies, and misinterpretation of research, as well as potential links to think tanks and interest groups. The paper concludes that climate change science does need to improve its communication strategies but that the world-view of some individuals and interests likely precludes acceptance. The connection between ACC and sustainability illustrates the need for debate on adaptation and mitigation strategies, but that debate needs to be grounded in scientific principles not unsupported skepticism.
Mesoscale models of dispersions stabilized by surfactants and colloids
Sman, R.G.M. van der; Meinders, M.B.J. - \ 2014
Advances in Colloid and Interface Science 211 (2014). - ISSN 0001-8686 - p. 63 - 76.
dissipative particle dynamics - fluid-fluid interfaces - lattice-boltzmann simulations - phase-separation dynamics - pickering emulsions - soluble surfactants - amphiphilic fluids - binary fluids - adsorption - flows
In this paper we discuss and give an outlook on numerical models describing dispersions, stabilized by surfactants and colloidal particles. Examples of these dispersions are foams and emulsions. In particular, we focus on the potential of the diffuse interface models based on a free energy approach, which describe dispersions with the surface-active agent soluble in one of the bulk phases. The free energy approach renders thermodynamic consistent models with realistic sorption isotherms and adsorption kinetics. The free energy approach is attractive because of its ability to describe highly complex dispersions, such as emulsions stabilized by ionic surfactants, or surfactant mixtures and dispersions with surfactant micelles. We have classified existing numerical methods into classes, using either a Eulerian or a Lagrangian representation for fluid and for the surfactant/colloid. A Eulerian representation gives a more coarse-grained, mean field description of the surface-active agent, while a Lagrangian representation can deal with steric effects and larger complexity concerning geometry and (amphiphilic) wetting properties of colloids and surfactants. However, the similarity between the description of wetting properties of both Eulerian and Lagrangian models allows for the development of hybrid Eulerian/Lagrangian models having advantages of both representations.
Improving internal communication between marketing and technology functions for successful new food product development
Jacobsen, L.F. ; Grunert, K.G. ; Søndergaard, H.A. ; Steenbekkers, B. ; Dekker, M. ; Lähteenmäki, L. - \ 2014
Trends in Food Science and Technology 37 (2014)2. - ISSN 0924-2244 - p. 106 - 114.
r-and-d - knowledge management - innovation - performance - integration - perspective - industry - projects - flows - teams
In order to increase the new product development (NPD) success for novel food products, it is crucial to understand how information can be optimally disseminated within companies. This systematic literature review concentrates on factors influencing internal communication between market and technology experts within the NPD process from a food industry point of view. The review provides practical implications for improving internal communication in food companies and identifies knowledge gaps. By focussing on optimising organisational structure, team composition, management support, and knowledge management, food companies can enhance internal communication between market and technology functions during the NPD process.
Bounded Biofuels? Sustainability of Global Biogas Developments
Mol, A.P.J. - \ 2014
Sociologia Ruralis 54 (2014)1. - ISSN 0038-0199 - p. 1 - 20.
renewable energy - ecological modernization - trade - flows - perspectives - governance - prospects - china - urban
Compared to liquid biofuels biogas has hardly drawn any attention from social sciences researchers lately. Although the share of biogas and liquid biofuels in the energy portfolio of many countries are comparable, biogas systems are strongly place-based and are non-controversial in terms of sustainability. But is that a fundamental distinction between the two biofuel systems; or is it just a matter of time before biogas becomes globally integrated and subject to sustainability controversies? In using a sociology of networks and flows frame, the current state of and developments in biogas systems around the world are analysed. It is concluded that biogas systems are most likely to further globally integrate, but that it remains to be seen whether that will result in similar sustainability controversies as with respect to liquid biofuels. One determining factor is whether governance arrangements manage to condition the sustainability of globalising biogas developments.
Whole-farm nitrogen cycling and intensification of crop-livestock systems in the highlands of Madagascar: An application of network analysis
Alvarez, S. ; Rufino, M.C. ; Vayssières, J. ; Salgado, P. ; Tittonell, P.A. ; Tillard, E. ; Bocquier, F. - \ 2014
Agricultural Systems 126 (2014). - ISSN 0308-521X - p. 25 - 37.
soil fertility management - nutrient balances - exploring diversity - efficiencies - resource - manure - flows - kenya - conservation - agriculture
Food insecurity, soil fertility depletion and strong competition for biomass are commonly observed in smallholder crop-livestock systems. The objective of this study was to explore options to improve farm-level nitrogen cycling, productivity and economic performance through the analysis of N flows within four contrasting crop-livestock farm systems of Madagascar highlands. Farms were conceptualized as networks where the compartments were the household and their farming activities, all connected by N flows. Indicators assessing network size and cycling, and the organization and diversity of the N flows, were compared with system productivity, food self-sufficiency, and gross margins for the current situation and under four scenarios of intensification (i) dairy production increased by increasing N inputs as supplementary feed; (ii) crop production increased by increasing N inputs as mineral fertilizer; (iii) manure management improved to increase N conservation during storage and application to soils; (iv) a combination of the two most economically attractive scenarios (i and iii). The four case study farms represent local diversity differing widely in terms of network size, with total annual system N throughput ranging from 113 to 1037kgN per capita, and in terms of N cycling, from 3 to 41kgN per capita per year. They differed less in terms of external dependence, from 0.26 to 0.41kgN kgN-1. Improving N conservation through improved manure management (scenario iii) had a positive impact on gross margin, and this in combination with increased concentrate supply (scenario iv) led to increases in whole-farm N use efficiencies from 2% to 50%, in N cycling from 9% to 68% and in food self-sufficiency from 12% to 37% across farm types. Gross margin was the most sensitive indicator to changes in management. Intensification through scenario iv had the highest impact on farm productivity, gross margin, food self-sufficiency, and environment sustainability (N use efficiency, capacity of the soil to stock N)
Investigation of Lattice Boltzmann wetting boundary conditions for capillaries with irregular polygonal cross-section
Sman, R.G.M. van der - \ 2013
Computer Physics Communications 184 (2013)12. - ISSN 0010-4655 - p. 2751 - 2760.
binary fluids - porous-media - simulations - flows - model - equation - configurations - dynamics - schemes
We have investigated the performance of an alternative wetting boundary condition for complex geometries in a phase field Lattice Boltzmann scheme, which is an alternative to the commonly used formulation by Yeomans and coworkers. Though our boundary condition is much simpler in its implementation, all investigated schemes show proper droplet spreading behaviour following the Cox-Voinov law. Still, numerical artefacts like spurious velocities or chequer board effects in the pressure field can be significantly reduced by the use of a two-relaxation-time (TRT) scheme, likewise recent studies by the Yeomans group. The outstanding property of our implementation is the presence of an (artificial) thin wetting layer, which influences the relation between the saturation (S-w) and capillary pressure p(cap) in channels with irregular polygonal cross section. The p(cap) (S-w) relation from our simulation follows the shifted-Young-Laplace (sYL) law, showing that the physics of this wetting layer is similar to precursor films due to Van der Waals forces. With the knowledge of the thickness of the wetting layer, simulation results can be translated back to realistic pore configurations with thinner wetting layers. (C) 2013 Elsevier B.V. All rights reserved.
Assessing phosphate rock depletion and phosphorus recycling options
Koppelaar, R.H.E.M. ; Weikard, H.P. - \ 2013
Global environmental change : human and policy dimensions 23 (2013)6. - ISSN 0959-3780 - p. 1454 - 1466.
economics - perspective - benefits - biomass - waste - flows
We analyze global elemental phosphorus flows in 2009 for (1) mining to products, (2) animal and human manure flows, (3) crop harvests and animal production, (4) food production, (5) soil erosion, (6) and crop uptake. Informed by the flow assessment the potential and cost of phosphorus usage reduction and recycling measures are quantified, and fed into a constructed phosphorus supply-demand model with reserve assessment to assess the impact of these measures on phosphate rock resource availability. According to our results in 2009 globally 21.4 Mt elemental phosphorus from rock phosphate was consumed in products of which 17.6 Mt used as fertilizers, fully able to cover erosion losses and outputs in agriculture in aggregate, but insufficient from the perspective of bio-available phosphorus in soils. We find substantial scope for phosphorus use reduction, at potentially 6.9 Mt phosphorus, or 32% of 2009 phosphate rock supply. Another 6.1 Mt, or 28% can technologically be recycled from waterways and wastewater, but at a cost substantially above any foreseeable phosphate rock fertilizer price. The model results suggests phosphate rock reserves are sufficient to meet demand into the 22nd century, and can be extended well into the 23rd century with assessed use reduction and recycling measures
Hydrodynamic cavitation: a bottom-up approach to liquid aeration
Raut, J.S. ; Stoyanov, S.D. ; Duggal, C. ; Pelan, E.G. ; Arnaudov, L.N. ; Naik, V.M. - \ 2012
Soft Matter 8 (2012)17. - ISSN 1744-683X - p. 4562 - 4566.
converging-diverging nozzle - saccharomyces-cerevisiae - trichoderma-reesei - flows
We report the use of hydrodynamic cavitation as a novel, bottom-up method for continuous creation of foams comprising of air microbubbles in aqueous systems containing surface active ingredients, like proteins or particles. The hydrodynamic cavitation was created using a converging-diverging nozzle. The air bubble size obtained using this technique was found to be significantly smaller than that achieved using conventional mechanical entrapment of air via shearing or shaking routes, which are in essence top-down approaches. In addition, the technique provided the possibility of forming non-spherical bubbles due to the high elongational stresses experienced by the bubbles as they flow through the nozzle throat. We show that surface active agents with a high surface elasticity modulus can be used to stabilize the nascent air bubbles and keep their elongated shapes for prolonged periods of time. This combination of the cavitation process with appropriate surface active agents offers an opportunity for creating bubbles smaller than 10 microns, which can provide unique benefits in various applications.
Nitrogen and phosphorus use efficiencies and losses in the food chain in China at regional scales in 1980 and 2005.
Ma, L. ; Velthof, G.L. ; Wang, F.H. ; Qin, Wei ; Zhang, W.F. ; Wei, J. ; Lesschen, J.P. ; Ma, W.Q. ; Oenema, O. ; Zhang, F.S. - \ 2012
Science of the Total Environment 434 (2012). - ISSN 0048-9697 - p. 51 - 61.
on-farm evaluation - taihu lake region - environmental impacts - n2o emissions - agriculture - management - flows - plain - perspective - systems
Crop and animal production in China has increased significantly during the last decades, but at the cost of large increases in nitrogen (N) and phosphorus (P) losses, which contribute to ecosystem degradation and human health effects. This information is largely based on scattered field experiments, surveys and national statistics. As a consequence, there is as yet no comprehensive understanding of the changes in N and P cycling and losses at regional and national scales. Here, we present the results of an integrated assessment of the N and P use efficiencies (NUE and PUE) and N and P losses in the chain of crop and animal production, food processing and retail, and food consumption at regional scale in 1980 and 2005, using a uniform approach and databases. Our results show that the N and P costs of food production–consumption almost doubled between 1980 and 2005, but with large regional variation. The NUE and PUE of crop production decreased dramatically, while NUE and PUE in animal production increased. Interestingly, NUE and PUE of the food processing sector decreased from about 75% to 50%. Intake of N and P per capita increased, but again with large regional variation. Losses of N and P from agriculture to atmosphere and water bodies increased in most regions, especially in the east and south of the country. Highest losses were estimated for the Beijing and Tianjin metropolitan regions (North China), Pearl River Delta (South China) and Yangzi River Delta (East China). In conclusion, the changes and regional variations in NUE and PUE in the food chain of China are large and complex. Changes occurred in the whole crop and animal production, food processing and consumption chain, and were largest in the most populous areas between 1980 and 2005.
Ideotyping integrated aquaculture systems to balance soil nutrients.
Muendo, P.N. ; Stoorvogel, J.J. ; Verdegem, M.C.J. ; Mora Vallejo, A.P. ; Verreth, J.A.J. - \ 2011
Journal of Agriculture and Rural Development in the Tropics and Subtropics 112 (2011)2. - ISSN 1612-9830 - p. 157 - 168.
channel catfish ponds - farming systems - economic-performance - fish ponds - chemical fertilizers - water-quality - nitrogen - manure - cattle - flows
Due to growing land scarcity and lack of nutrient inputs, African farmers switched from shifting cultivation to continuous cropping and extended crop area by bringing fragile lands such as river banks and hill slopes into production. This accelerated soil fertility decline caused by erosion, harvesting and insufficient nutrient replenishment. We explored the feasibility to reduce nutrient depletion by increasing nutrient utilization efficiencies, while diversifying and increasing food production through the development of integrated aquaculture – agriculture (IAA). Considering the climatic conditions prevailing in Kenyan highlands, aquaculture production scenarios were ideotyped per agro-ecological zone. These aquaculture production scenarios were integrated into existing NUTrient MONitoring (NUTMON) farm surveydata for the area. The nutrient balances and flows of the resulting IAA-systems were compared to present land use.The effects of IAA development on nutrient depletion and total food production were evaluated. With the development of IAA systems, nutrient depletion rates dropped by 23–35%, agricultural production increased by 2–26% and overall farm food production increased by 22–70%. The study demonstrates that from a bio-physical point of view, the development of IAA-systems in Africa is technically possible and could raise soil fertility and total farm production. Further studies that evaluate the economic feasibility and impacts on the livelihood of farming households are recommended.
The phosphorus footprint of China's food chain: implications for food security, natural resource management, and environmental quality
Wang, F. ; Sims, J.T. ; Ma, L. ; Ma, W. ; Dou, Z. ; Zhang, F. - \ 2011
Journal of Environmental Quality 40 (2011)4. - ISSN 0047-2425 - p. 1081 - 1089.
nitrogen - system - flows - agriculture
Efficient use of phosphorus (P) for producing food, preventing water pollution, and managing a dwindling rock P reserve are major challenges for China. We analyzed P stocks and flows in the Chinese food chain to identify where P use efficiency can be improved, where P leaks to the environment, and the research, technologies, and policies needed to improve P use. We found a high degree of inefficiency; of 6652 Gg P entering the food chain, only 1102 Gg P (18%) exit as food for humans. The greatest inefficiencies were a large build-up of soil P (3670 Gg P yr-1; 52% of P inputs) and high P losses to the environment from animal production (1582 Gg P yr-1; 60% of excreted P). Improving P use in China must focus on national-scale nutrient management strategies, better animal nutrition, and adoption of technologies and policies to reduce P discharges from the animal sector and recycle P as manures in agriculture.
Evaluation of the COSMO-SC turbulence scheme in a shear-driven stable boundary layer
Buzzi, M. ; Rotach, M.W. ; Raschendorfer, M. ; Holtslag, A.A.M. - \ 2011
Meteorologische Zeitschrift 20 (2011)3. - ISSN 0941-2948 - p. 335 - 350.
weather prediction model - 2nd-order closure models - low-level jet - intermittent turbulence - surface - flows - land - oscillations - coordinate - stability
The performance of the COSMOsingle column turbulence scheme (a TKE scheme with a 1.5 order turbulence closure at the hierarchy level 2.5 following Mellor and Yamada) is investigated in the framework of the first GABLS intercomparison case. This is an idealized shear-driven stable boundary layer case with no advection. Overall the COSMO model performs reasonably well compared to the other participating models and the reference Large Eddy Simulations. However, the modification of some model parameters, together with the prescribed high vertical resolution, reveals a problem of numerical stability in the turbulence scheme: for the investigated shear-driven stable boundary layer the vertical diffusivities show unrealistic oscillations. This model deficiency, which has previously been described in literature, is explored in quite substantial detail and possible solutions are evaluated. It is found that under the given conditions the numerical description of the vertical wind gradients is crucial for the stability of the turbulence scheme. It is shown that for the determination of vertical gradients information from grid points beyond the immediately neighboring model levels must be incorporated – as it is common practice in the treatment of horizontal gradients – in order to obtain a numerically stable turbulence scheme. As a first approach vertical wind gradients are filtered using a 5-point filter prior to the evaluation of the stability functions. This approach yields to the overall best performance among all those tested and found in literature. The simulations additionally show that the use of a too high minimum diffusion coefficient (which is introduced in the model in order to avoid too low mixing) leads to losing important structures of the planetary boundary layer, such as the low level jet or a near-surface temperature inversion
Towards eco-agro industrial clusters in aquatic production: the case of shrimp processing industry in Vietnam
Pham Thi Ahn, ; Tran Thi My Dieu, ; Mol, A.P.J. ; Kroeze, C. ; Bush, S.R. - \ 2011
Journal of Cleaner Production 19 (2011)17-18. - ISSN 0959-6526 - p. 2107 - 2118.
waste-water treatment - anaerobic treatment - cleaner production - flows - reuse - plant
The concept of industrial ecology has been applied in this research to study possibilities to develop an eco-industrial cluster model for fishery production industry in Vietnam. By learning from experiments of other developed countries, we apply the principles of Industrial Ecology and of Ecological Modernization in the context of Vietnam. We design a physical-technological conceptual model for minimizing waste in agro-industries, with a case study of frozen shrimp production. The results indicate that it is possible and feasible to develop an eco-industrial cluster including aquaculture, fishery processing companies, by-product plants, and wastewater treatment units. By doing so, aquaculture and industry can cooperate for environmentally sound development. Actors and institutions that may govern the proposed eco-industrial cluster of shrimp processing industry are also analysed in this paper. The economic feasibility of the designed eco-agro industrial cluster for fish production in Vietnam depends on the energy savings and effective revenues gained from selling the produced valuable materials, such as Chitosan and animal feed.
Social theory and the environment in the new world (dis)order
Sonnenfeld, D.A. ; Mol, A.P.J. - \ 2011
Global environmental change : human and policy dimensions 21 (2011)3. - ISSN 0959-3780 - p. 771 - 775.
governance - flows
Modeling the soil nutrient balance of integrated agriculture-aquaculture systems in the Mekong Delta, Vietnam
Phong, L.T. ; Stoorvogel, J.J. ; Mensvoort, M.E.F. van; Udo, H.M.J. - \ 2011
Nutrient Cycling in Agroecosystems 90 (2011)1. - ISSN 1385-1314 - p. 33 - 49.
farming systems - economic-performance - nitrogen-balance - irrigated rice - n-loss - phosphorus - nutmon - flows - scale - crop
This study quantifies soil nutrient balances of Integrated Agriculture-Aquaculture Systems in the Mekong Delta of Vietnam. Eleven farms were monitored to collect data on farm activities and nutrient inputs and outputs to compute these balances of the rice-based and high input fish system in O Mon district (R-HF); the rice-based and medium input fish system in Tam Binh district (R-MF); and the orchard-based and low input fish system in Cai Be district (O-LF). For the estimation, the Nutmon model has been adapted to the specific conditions in these integrated systems in Asia (Nutmon-Asia). New regression models of leaching and gaseous losses of nitrogen were applied to fields used for upland crops and paddy rice. Reference values were used for the assessment of nitrogen fixation in paddy soils, wet atmospheric deposition, and irrigation water. The results showed that farms in all three systems have nitrogen, phosphorus and potassium surpluses (84 kg N, 73 kg P, and 69 kg K ha-1 year-1). The O-LF system had the smallest nitrogen surplus while the smallest surplus of phosphorus and potassium was seen in the R-HF system. High surpluses of phosphorus and potassium were found in vegetable fields, whereas a negative potassium balance was found in the rice fields of all three systems. The positive farm nutrient balances indicate that it is likely that soil fertility will be maintained although there is a risk for environmental contamination
Phosphorus demand for the 1970-2100 period: A scenario analysis of resource depletion
Vuuren, D.P. van; Bouwman, A.F. ; Beusen, A.H.W. - \ 2010
Global environmental change : human and policy dimensions 20 (2010)3. - ISSN 0959-3780 - p. 428 - 439.
world - flows - environment - perspective - nutrient
The phosphorus (P) cycle has been significantly altered by human activities. For this paper, we explored the sustainability of current P flows in terms of resource depletion and the ultimate fate of these flows. The analysis shows that rapid depletion of extractable phosphate rock is not very likely, in the near term. Under best estimates, depletion would be around 20-35%. In worst case scenarios, about 40-60% of the current resource base would be extracted by 2100. At the same time, production will concentrate in Asia, Africa and West Asia, and production costs will likely have increased. As there are no substitutes for phosphorus plant nutrients in agriculture, arguably even partial depletion of P resources may in the long run be relevant for the sustainability of agriculture. Consumption trends lead to large flows of phosphorus to surface water and a considerable build-up of phosphorus in agricultural soils in arable lands. This may allow a reduction in future P fertiliser application rates in crop production. Results also indicate a global depletion of P pools in soils under grassland, which may be a threat to ruminant production.
Anthropogenic nitrogen autotrophy and heterotrophy of the world's watersheds: Past, present, and future trends
Billen, G. ; Beusen, A. ; Bouwman, L. ; Garnier, J. - \ 2010
Global Biogeochemical Cycles 24 (2010). - ISSN 0886-6236 - 12 p.
long-term - international-trade - production systems - river continuum - seine - transfers - flows - meat
Anthropogenic nitrogen autotrophy of a territory is defined as the nitrogen flux associated with local production of harvested crops and grass consumed by livestock grazing (in kg N/km(2)/yr). Nitrogen heterotrophy is the nitrogen flux associated with local food and feed consumption by humans and domestic animals. These two summarizing characteristics (anthropogenic nitrogen autotrophy and heterotrophy (ANAH)) indicate the degree of anthropogenic perturbation of the nitrogen cycle by agriculture and human consumption: their balance value provides information on either the potential for commercial export or the need to import agricultural goods; in a watershed, their vector sum is related to the nitrogen flux delivered to the sea. These indicators were calculated for all the watersheds in the Global Nutrient Export from Watersheds (NEWS) database for 1970 and 2000, as well as for 2030 and 2050, according to Millennium Ecosystem Assessment scenarios. During this 30 year period, many watersheds shifted from relatively balanced situations toward either more autotrophic or more heterotrophic conditions. This trend is predicted to become more pronounced over the next 50 years
The hydrological response of the Ourthe catchment to climate change as modelled by the HBV model
Driessen, T.L.A. ; Hurkmans, R.T.W.L. ; Terink, W. ; Hazenberg, P. ; Torfs, P.J.J.F. ; Uijlenhoet, R. - \ 2010
Hydrology and Earth System Sciences 14 (2010). - ISSN 1027-5606 - p. 651 - 665.
river rhine - simulation - impact - basin - calibration - discharge - output - flows
The Meuse is an important river in Western Europe, which is almost exclusively rain-fed. Projected changes in precipitation characteristics due to climate change, therefore, are expected to have a considerable effect on the hydrological regime of the river Meuse. We focus on an important tributary of the Meuse, the Ourthe, measuring about 1600 km2. The well-known hydrological model HBV is forced with three high-resolution (0.088°) regional climate scenarios, each based on one of three different IPCC CO2 emission scenarios: A1B, A2 and B1. To represent the current climate, a reference model run at the same resolution is used. Prior to running the hydrological model, the biases in the climate model output are investigated and corrected for. Different approaches to correct the distributed climate model output using single-site observations are compared. Correcting the spatially averaged temperature and precipitation is found to give the best results, but still large differences exist between observations and simulations. The bias corrected data are then used to force HBV. Results indicate a small increase in overall discharge, especially for the B1 scenario during the beginning of the 21st century. Towards the end of the century, all scenarios show a decrease in summer discharge, partially because of the diminished buffering effect by the snow pack, and an increased discharge in winter. It should be stressed, however, that we used results from only one GCM (the only one available at such a high resolution). It would be interesting to repeat the analysis with multiple models