Multi-stakeholder development of a serious game to explore the water-energy-food-land-climate nexus: The SIM4NEXUS approach

This is the final version of the article. Available from the publisher via the DOI in this record.Water, energy, food, land and climate form a tightly-connected nexus in which actions on one sector impact other sectors, creating feedbacks and unanticipated consequences. This is especially because at present, much scientific research and many policies are constrained to single discipline/sector silos that are often not interacting (e.g., water-related research/policy). However, experimenting with the interaction and determining how a change in one sector could impact another may require unreasonable time frames, be very difficult in practice and may be potentially dangerous, triggering any one of a number of unanticipated side-effects. Current modelling often neglects knowledge from practice. Therefore, a safe environment is required to test the potential cross-sectoral implications of policy decisions in one sector on other sectors. Serious games offer such an environment by creating realistic 'simulations', where long-term impacts of policies may be tested and rated. This paper describes how the ongoing (2016-2020) Horizon2020 project SIM4NEXUS will develop serious games investigating potential plausible cross-nexus implications and synergies due to policy interventions for 12 multi-scale case studies ranging from regional to global. What sets these games apart is that stakeholders and partners are involved in all aspects of the modelling definition and process, from case study conceptualisation, quantitative model development including the implementation and validation of each serious game. Learning from playing a serious game is justified by adopting a proof-of-concept for a specific regional case study in Sardinia (Italy). The value of multi-stakeholder involvement is demonstrated, and critical lessons learned for serious game development in general are presented.The work described in this paper has been conducted within the project SIM4NEXUS. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under Grant Agreement No. 689150 SIM4NEXUS

Non-lethal control of the cariogenic potential of an agent-based model for dental plaque

Dental caries or tooth decay is a prevalent global disease whose causative agent is the oral biofilm known as plaque. According to the ecological plaque hypothesis, this biofilm becomes pathogenic when external challenges drive it towards a state with a high proportion of acid-producing bacteria. Determining which factors control biofilm composition is therefore desirable when developing novel clinical treatments to combat caries, but is also challenging due to the system complexity and the existence of multiple bacterial species performing similar functions. Here we employ agent-based mathematical modelling to simulate a biofilm consisting of two competing, distinct types of bacterial populations, each parameterised by their nutrient uptake and aciduricity, periodically subjected to an acid challenge resulting from the metabolism of dietary carbohydrates. It was found that one population was progressively eliminated from the system to give either a benign or a pathogenic biofilm, with a tipping point between these two fates depending on a multiplicity of factors relating to microbial physiology and biofilm geometry. Parameter sensitivity was quantified by individually varying the model parameters against putative experimental measures, suggesting non-lethal interventions that can favourably modulate biofilm composition. We discuss how the same parameter sensitivity data can be used to guide the design of validation experiments, and argue for the benefits of in silico modelling in providing an additional predictive capability upstream from in vitro experiments

Incorporating Ecosystems in the Water-Energy-Food Nexus: Current Perspective and Future Directions

Integrated approaches for managing natural resources are needed to meet the increasing demand for freshwater, energy and food, while, in parallel, mitigating and adapting to climate change, maintaining the integrity of ecosystems, and ensuring equitable access to resources. The Water-Energy-Food (WEF) Nexus has been proposed as a cross-sectoral approach to understand, analyse, and manage the complex trade-offs and exploit synergies that arise among these resource sectors. Although not initially included as a component of the Nexus, the importance of ecosystems in supporting water, energy and food security is increasingly recognised by the Nexus community of researchers and practitioners. However, attempts to conceptually integrate Ecosystems into the Nexus have yet to converge into a common framework. A group of natural resources management researchers, system thinkers and ecosystem services experts from the European network COST Action CA20138 NEXUSNET have compiled and investigated the various approaches for integrating ecosystems in the WEF Nexus. By combining literature analysis with interdisciplinary workshops – one of which was held in a hybrid format (in person and online) at the University of Oulu, Finland, in September 2022 – we reveal a multiplicity of concepts utilised to represent, partially or fully, ecosystems in the Nexus, namely “natural environment”, “ecosystem services” and “biodiversity”. Disparity was also found in the role attributed to ecosystems in the Nexus framework, being it an underlying layer from which resources for Nexus sectors are extracted or the pillar of an expanded Nexus system – i.e., the WEF-Ecosystems Nexus. Through this collaborative effort, we present possible advantages and disadvantages of adopting differential WEF-Ecosystems Nexus approaches, highlighting their potential complementarity and integration to support future advancement of Nexus research. In the oral presentation, we will show our preliminary findings and encourage the exchange of ideas and feedback from the different scientific disciplines present at the CEMEPE Conference.Tenth International Conference on Environmental Management, Engineering, Planning and Economics (CEMEPE) & SECOTOX Conference organized by: Division of Hydraulics and Environmental Engineering, Department of Civil Engineering, Aristotle University of Thessaloniki and Society of Ecotoxicology and Environmental Safety (SECOTOX), Skiathos island, Greece, 2023

A mathematical model of quorum sensing regulated EPS production in biofilm communities

<p>Abstract</p> <p>Background</p> <p>Biofilms are microbial communities encased in a layer of extracellular polymeric substances (EPS). The EPS matrix provides several functional purposes for the biofilm, such as protecting bacteria from environmental stresses, and providing mechanical stability. Quorum sensing is a cell-cell communication mechanism used by several bacterial taxa to coordinate gene expression and behaviour in groups, based on population densities.</p> <p>Model</p> <p>We mathematically model quorum sensing and EPS production in a growing biofilm under various environmental conditions, to study how a developing biofilm impacts quorum sensing, and conversely, how a biofilm is affected by quorum sensing-regulated EPS production. We investigate circumstances when using quorum-sensing regulated EPS production is a beneficial strategy for biofilm cells.</p> <p>Results</p> <p>We find that biofilms that use quorum sensing to induce increased EPS production do not obtain the high cell populations of low-EPS producers, but can rapidly increase their volume to parallel high-EPS producers. Quorum sensing-induced EPS production allows a biofilm to switch behaviours, from a colonization mode (with an optimized growth rate), to a protection mode.</p> <p>Conclusions</p> <p>A biofilm will benefit from using quorum sensing-induced EPS production if bacteria cells have the objective of acquiring a thick, protective layer of EPS, or if they wish to clog their environment with biomass as a means of securing nutrient supply and outcompeting other colonies in the channel, of their own or a different species.</p

GREY WATER FOOTPRINT OF CROPS AND CROP-DERIVED PRODUCTS: ANALYSIS OF CALCULATION METHOD

The explosive increase in world population, along with the fast socio-economic development, have led to an increased water demand; the impact of global water resource consumption is mapped with the "water footprint", which is the total volume of freshwater used to produce the goods and services consumed. "Virtual water" is the volume of water used to produce a commodity, and is classified as green, blue and grey. "Blue water" refers to the volume of fresh water consumed along the supply chain of a product; "green" quantifies the volume of precipitation stored as soil moisture, and "grey" measures the volume of water required to dilute pollutants associated with a product's production chain to meet ambient water quality standards. When applied to agricultural crops, the calculation of grey water requires the following quantities: fertilizer application rate, crop yield, fertilizer leaching fraction, maximum allowed pollutant concentration in natural waters, and in the water where pollution is rejected. Much of this data is unavailable and researchers seem to proceed with a series of assumptions to calculate grey water figures. In this article, the common assumptions are reviewed, and prominence is given to weaknesses and the sensitivity of the calculation method

Variation in the mechanical properties of a porous multi-phase biofilm under compression due to void closure

Biofilm properties change drastically from one point to another inside the matrix, and from one minute to the next, bringing about similar variations in biofilm mechanical properties, both in time and space. In this article, we present a theory that quantifies deformation-dependent changes in the mechanical properties of a composite porous material that undergoes compression. Such changes are a result of the pores either closing (when the biofilm is under compression) or opening (when under tension). The theory borrows well-established principles of continuum mechanics and is modified to represent a biofilm composed of four different phases, three different solid biomass materials (active biomass, extracellular polymers and inert biomass) and pores. We see that, when the evolution of the volume fractions of the different phases in a uniaxial compression test is taken into account, the material "hardens" or becomes stiffer as the deformation increases, due to void closure. Once complete void closure is achieved, the material reaches its maximum stiffness. Different homogenisation schemes are presented and comparisons are performed with stress-strain calculations for all of them. © IWA Publishing 2007

Identifying and quantifying nitrogen and phosphorus loadings from agriculture and livestock waste in the Penios River Basin District

The nitrogen and phosphorus loadings coming from diffuse, non-point pollution sources related to agriculture and animal husbandry in the Penios river basin in the region of Thessaly, Greece, were estimated. Detailed data on types of crops and field area as well as types and numbers of animals bred in the municipal districts included in the Penios River Basin District were collected from agricultural cooperatives and rural agencies in Thessaly. Related nitrogen and phosphorus loadings were calculated and all data were mapped in a geographic information system (GIS) environment to show how diffuse pollution is spatially distributed in the Penios basin and to identify areas with the highest anthropogenic pressures. This type of data is useful to a driving forces-pressures-state-impacts-responses (DPSIR) analysis - a tool suitable for the analysis of environmental decisions in the direction of sustainable development

Theoretical Perspectives and Empirical Facts on Water Sector Privatization: The Greek Case Against European and Global Trends

The scope of this paper is to investigate the Greek 'path' to water privatization and its possible interconnections with the ongoing restructuring of the water sector on an EU and a global level. The paper starts with a contemporary, spatially-sensitive analysis of the expanding role of water multinationals, by focusing on water supply operators of the southern EU. Afterwards, it highlights the peculiarities of the 'Greek path' to private sector participation by studying the two most important Greek water companies, in the cities of Athens and Thessaloniki respectively. As found, these companies have partially, though successfully, been transformed according to the rules of the 'market-environmentalist' paradigm. The state drives the privatization effort, while at the same time, insufficiently regulates the activity of both companies. Based on the Greek case, the paper discusses whether the analytical tools offered by a critical approach, the 'accumulation-by-dispossession' thesis, can better interpret changes in water companies of the 'advanced-South'

MUNICIPAL SOLID WASTE MANAGEMENT AND LANDFILL SITE SELECTION IN GREECE: IRRATIONALITY VERSUS EFFICIENCY

Municipal solid waste (MSW) collection and disposal is a major problem of urban environment in the world today. MSW management solutions have to be technologically feasible, legally and socially acceptable and environmentally and financially sustainable. European policy is pushing to a rational management of natural resources; a promising technological perspective today is waste valorization, a process that becomes possible through sorting at the source, combined with material recycling and waste-to-energy methods. On the other hand, technologies like mechanical sorting, or disposal of MSW in landfills do not really improve MSW management efficiency. Landfills should become the ultimate disposal site of a few inert residuals from MSW valorization. Despite all this, conventional landfills for disposal of mixed MSW are still being constructed, with landfill site selection being a major social problem due to the lack of public acceptance; objectivity in landfill site selection is therefore extremely important. In Greece, we find several examples of inefficient MSW management and curious landfill site selection. In this paper, we criticize environmental policy issues for MSW management in Greece and identify weak points in the criteria used for the selection of landfill sites. We conclude that there is a real need for rational MSW management based on high quality scientific input