Recycling Of Elements Research Articles

Secretory Autophagy Forges a Therapy Resistant Microenvironment in Melanoma.

Simple SummaryTumor microenvironment (TME) is a complex of many cell types and extracellular matrix that play an active role in regulating and sustaining melanoma tumor progression. In this context, the secretion of several molecules, by secretory autophagy or exosome release, stimulates the intercellular communication between the different components of the TME modulating tumor response. Here, we discuss the current awareness around the role of extracellular secretion in melanoma TME and also investigate the molecules related to these secretion pathways in melanoma progression using public databases.Melanoma is the most aggressive skin cancer characterized by high mutational burden and large heterogeneity. Cancer cells are surrounded by a complex environment, critical to tumor establishment and progression. Thus, tumor-associated stromal components can sustain tumor demands or impair cancer cell progression. One way to manage such processes is through the regulation of autophagy, both in stromal and tumor cells. Autophagy is a catabolic mechanism that provides nutrients and energy, and it eliminates damaged organelles by degradation and recycling of cellular elements. Besides this primary function, autophagy plays multiple roles in the tumor microenvironment capable of affecting cell fate. Evidence demonstrates the existence of novel branches in the autophagy system related to cytoplasmic constituent’s secretion. Hence, autophagy-dependent secretion assembles a tangled network of signaling that potentially contributes to metabolism reprogramming, immune regulation, and tumor progression. Here, we summarize the current awareness regarding secretory autophagy and the intersection with exosome biogenesis and release in melanoma and their role in tumor resistance. In addition, we present and discuss data from public databases concerning autophagy and exosome-related genes as important mediators of melanoma behavior. Finally, we will present the main challenges in the field and strategies to translate most of the pre-clinical findings to clinical practice.

Solubilization of struvite and biorecovery of cerium by Aspergillus niger

Cerium has many modern applications such as in renewable energies and the biosynthesis of nanomaterials. In this research, natural struvite was solubilized by Aspergillus niger and the biomass-free struvite leachate was investigated for its ability to recover cerium. It was shown that struvite was completed solubilized following 2 weeks of fungal growth, which released inorganic phosphate (Pi) from the mineral by the production of oxalic acid. Scanning electron microscopy (SEM) showed that crystals with distinctive morphologies were formed in the natural struvite leachate after mixing with Ce3+. Energy-dispersive X-ray analysis (EDXA), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) confirmed the formation of cerium phosphate hydrate [Ce(PO4)·H2O] at lower Ce concentrations and a mixture of phosphate and cerium oxalate decahydrate [Ce2(C2O4)3·10H2O] at higher Ce concentrations. The formation of these biogenic Ce minerals leads to the removal of > 99% Ce from solution. Thermal decomposition experiments showed that the biogenic Ce phosphates could be transformed into a mixture of CePO4 and CeO2 (cerianite) after heat treatment at 1000 °C. These results provide a new perspective of the fungal biotransformation of soluble REE species using struvite leachate, and also indicate the potential of using the recovered REE as biomaterial precursors with possible applications in the biosynthesis of novel nanomaterials, elemental recycling and biorecovery.Key points• Cerium was recovered using a struvite leachate produced by A. niger.• Oxalic acid played a major role in struvite solubilization and Ce phosphate biorecovery.• Resulting nanoscale mineral products could serve as a precursor for Ce oxide synthesis.

The influence of market factors on the potential environmental benefits of the recycling of rare earth elements

<abstract> <p>After the rare earth element (REE) crisis in 2011, companies invested in new supply routes of REEs, such as the recycling from end-of-life fluorescent lamps. Although recycling is in the current market situation not economically profitable anymore, it does fit in a strategy towards a low-carbon and a circular economy, for example to mitigate the supply risk of REEs. However, is recycling of REEs indeed environmentally beneficial? Should their recycling therefore be subsidized? This is assessed with a Consequential Life Cycle Assessment (CLCA). The results show that the answer to this question strongly depends on the market situation of the REEs, and the applications in which they are used. At the time that the recycling process was operating—where fluorescent lamps could still displace halogen lamps and there was sufficient demand for the REE europium and yttrium—environmental benefits could be achieved by increasing the recovery of REEs from end-of-life fluorescent lamps. The results of this study can be used to increase the understanding on the type of market interactions that could be considered in the decision-making processes regarding the supply and recycling of raw materials—especially materials that are often produced as by-products, such as many critical raw materials.</p> </abstract>

Effective hydrometallurgical route for recovery of energy critical elements from E-wastes and future aspects

Rare earth elements and critical metals are available in significant quantities in electronic devices. As a result, proper electronic waste recycling and processing provide an opportunity to extract these metals from electronic waste. Although electronic waste (e-waste) is becoming a global environmental and public health concern, waste of electrical and electronic equipment (WEEE) is a considerable secondary resource of energy-critical elements (ECE) for green technology development. The latest developments in different hydrometallurgical techniques for the recycling of essential elements from WEEEs are summarised in this study. This study surveyedmany publications on WEEE management, acid leaching, and metal extraction from WEEE. The importance of ionic liquids is highlighted in particular. Different procedures and approaches for selective recovery of essential components from WEEEs leachates (solvent extraction using ionic liquids as extractants and chemical precipitation) are addressed. The potential for using WEEEs as secondary sources for important raw materials, as well as the technological, economic, and commercial benefits, are highlighted.

Sustainable Recycling of Rare-Earth Elements from NdFeB Magnet Swarf: Techno-Economic and Environmental Perspectives

Sustainable Recycling of Rare-Earth Elements from NdFeB Magnet Swarf: Techno-Economic and Environmental Perspectives

Closed-loop selective recycling process of spent LiNixCoyMn1−x-yO2 batteries by thermal-driven conversion

The consumption of lithium-ion batteries raises raw material demand for and the pressure on ecological sustainability. Metals can be recovered in shorter paths while considerably boosting material use, hence selective recycling of specific elements is becoming a hotspot. This paper proposes a thermally-driven closed-loop recycling process for scrap LiNi1/3Co1/3Mn1/3O2 cathodes, in which Li is efficiently extracted by water leaching. Then, by combining the leaching residue with Li2CO3, a solid-phase synthesis is carried out, with Li being targeted to heal into Ni-Co-Mn-O to construct the layered structure. The electrochemical performance of the resynthesized cathode material is comparable to that of the commercial LiNi0.5Co0.2Mn0.3O2 (NCM523) material. During the thermal-driven conversion, solid-state processes can be observed. To ensure charge conservation, Li+ in the unstable layered structure is released and mixed with SO42- to produce Li2SO4, and lattice oxygen escapes and transforms with Ni2+ to generate NiO. For the resynthesized process, the spherical shape of Ni-Co-Mn-O is largely retained. Notably, sulfur is remained in the form of SO42- throughout the closed-loop process and is therefore free of contamination. The thermal-driven conversion recycling process revealed in this study will encourage researchers to ensure more efforts in efficient and selective recovery for sustainable energy storage of rechargeable batteries.

High-Gradient Magnetic Separation of Compact Fluorescent Lamp Phosphors: Elucidation of the Removal Dynamics in a Rotary Permanent Magnet Separator

In an ongoing effort towards a more sustainable rare-earth element market, there is a high potential for an efficient recycling of rare-earth elements from end-of-life compact fluorescent lamps by physical separation of the individual phosphors. In this study, we investigate the separation of five fluorescent lamp particles by high-gradient magnetic separation in a rotary permanent magnet separator. We thoroughly characterize the phosphors by ICP-MS, laser diffraction analysis, gas displacement pycnometry, surface area analysis, SQUID-VSM, and Time-Resolved Laser-Induced Fluorescence Spectroscopy. We present a fast and reliable quantification method for mixtures of the investigated phosphors, based on a combination of Time-Resolved Laser-Induced Fluorescence Spectroscopy and parallel factor analysis. With this method, we were able to monitor each phosphors’ removal dynamics in the high-gradient magnetic separator and we estimate that the particles’ removal efficiencies are proportional to (d2·χ)1/3. Finally, we have found that the removed phosphors can readily be recovered easily from the separation cell by backwashing with an intermittent air–water flow. This work should contribute to a better understanding of the phosphors’ separability by high-gradient magnetic separation and can simultaneously be considered to be an important preparation for an upscalable separation process with (bio)functionalized superparamagnetic carriers.

Circular Construction Process: Method for Developing a Selective, Low CO2eq Disassembly and Demolition Plan

With the increasing focus on the construction sector (e.g., following the European Green Deal initiative) with the aim to reduce emissions by 55% by 2030 (compared to 1990 levels), as well as achieve full decarbonisation by 2050, the built environment remains a strategic domain for the R&I (Research and Innovation) agenda. Indeed, the building and construction sector is the main contributor to greenhouse gas emissions (39% of global emissions as of 2018), highlighting the need to start a process of decarbonisation of this sector. The overall reduction in the environmental impact of building materials is achieved by establishing sustainable continuity between the end-of-life phase of the building and the production phase of individual building components. In particular, with reference to the end-of-life phase of the building (BS EN 15978: 2011), the Minimum Environmental Criteria foresee the preparation of a plan for the disassembly and selective demolition of the building, which allows the reuse or recycling of materials, building components and prefabricated elements used. According to the guidelines of a low-carbon construction design, which takes into account a circular economy, the following thesis deals with a methodological proposal to study “dry” construction systems (wood and steel). In particular, the study intends to reach the development of such an elaboration by carrying out an assessment of the environmental impact of a process of selective disassembly and demolition of steel building systems. The model is developed on the basis of a reading of the level of sustainability of emblematic case studies, appropriately identified, i.e., ‘quality’ architectures, built with ‘dry’ (steel) building systems.

Transformation of lignocellulose to starch‐like carbohydrates by organic acid‐catalyzed pretreatment and biological detoxification

Corn dry milling provides a mature model for lignocellulose biorefinery process. To copy this technical success, a crucial step is to transform lignocellulose into starch-like carbohydrates (SLC), similar to milled corn grain and in a similar fashion to corn dry milling. The transformation process should be zero wastewater generation and sufficient fermentable sugar conservation; the product should be in solid particle form, free of toxic residues, and high enzymatic hydrolysis yield and fermentability. Here we designed and verified a SLC transformation process by (i) biodegradable oxalic acid-catalyzed pretreatment, and (ii) simultaneous biodegradation of inhibitors and oxalic acid catalyst. The oxalic acid catalyst was effective on disrupting the lignocellulose structure and also biodegradable at low pH value. The biodetoxification fungus Paecilomyces variotii FN89 was capable of degrading the furan/phenolic aldehydes and oxalic acid simultaneously and ultimately, while the fermentable sugars were well preserved. The obtained SLC from wheat straw and corn stover were similar to dry milled corn meal in terms of morphological properties, fermentable sugar contents, enzymatic hydrolysis yield, elemental contents, and free of inhibitors and acid catalyst. The bioconversion of starch-like wheat straw and corn stover produced 78.5 and 75.3 g/L of ethanol (9.9% and 9.5%, v/v) with the yield of 0.47 and 0.45 g ethanol/g cellulose/xylose, respectively, compared with 78.7 g/L (10.0%, v/v) from corn meal and the yield of 0.48 g ethanol/g starch. Mass balances suggest that the ethanol yield, wastewater generation, and elemental recycling of the SLC from lignocellulose were essentially the same as those of corn meal.

REUTILIZACIÓN DE ELEMENTOS DE ÓSMOSIS INVERSA DE LOS PROCESOS DE DESALACIÓN

This paper is based on the study for the evaluation of the processes of reuse and recycling of reverse osmosis components and membranes in the Canary Islands and Macaronesia, within the DESAL+ project and in the framework of the DESAL+ LIVING LAB platform, coordinated by the Canary Islands Technological Institute (ITC) and the Canary Islands Agency for Research, Innovation and Information Society (ACIISI), with the support of the Interreg-MAC Programme. Reverse osmosis membranes could be reused in the same or another desalination plant by replacing the membranes in the first, dirtier positions with those in the last, less damaged positions. Also, by changing the best first-stage membranes to the second and vice versa, the useful life of these membranes could be extended through chemical cleaning and a second life could be given in tertiary treatment plants, reuse in industrial processes where they use special reverse osmosis membranes and degrade rapidly, in processes with leachate from landfill waste and also an interesting option is the oxidation of reverse osmosis elements to obtain nano-filtration, ultrafiltration or micro-filtration membranes for the removal of physical dirt. The main categories of thermal processing recycling commonly used in industry include incineration and pyrolysis to produce energy, gas and fuel. These processes can be applied to mixed plastic waste, such as the combination of materials used in the manufacture of reverse osmosis membranes. The recycling of reverse osmosis elements from desalination plants is shown as an opportunity, nowadays existing pioneering initiatives in Europe. Energy recovery, via incineration, is feasible but is not considered in accordance with the environmental, social and political problems that this may generate. However, the recycling of the reverse osmosis elements via pyrolytic industry for fuel production can be centralized in a new industry already planned in the Canary Islands and all the osmosis membranes that are obsolete can be sent there. This is a technically and economically viable business opportunity with a promising future in today's recycling market as studied in the paper.

Modeling soil chemical changes induced by grassland afforestation in a sedimentary plain with shallow groundwater

Chemical changes produced by the establishment of tree plantations on grasslands occupying sedimentary plains could potentially impact their highly productive soils through multiple mechanisms. Some of the reported chemical changes following this vegetation shift include soil salinization, sodification, alkalization and acidification. While the associated hydrological, chemical and biological processes have been characterized in most cases, their quantitative integration remains as a complex challenge. The present work explored the simultaneous occurrence of the four mentioned soil chemical changes using reactive transport modeling and hydrological and chemical datasets (water, soil and plants) for a well described afforested grassland in the Pampas of Argentina. Processes included in the numerical model were unsaturated water flow, chemical reactions (soil cation exchange, mineral dissolution-precipitation), the intrusion of salty deep water induced by tree groundwater consumption, rhizosphere-plant processes (respiration, selective solute uptake/exclusion, root mediated electric charge compensation, and elemental recycling and uplift). Modeling results suggest that the dominant soil chemical changes depend on the interplay of all the aforementioned processes and help explain strong soil variation across very short distances (250 m) along edge-core gradients within the tree plantation. This complexity is hard to expect and explain from an isolated treatment of each of the aforementioned processes, calling for the application of numerical tools.

Microbially-Enhanced Vanadium Mining and Bioremediation Under Micro- and Mars Gravity on the International Space Station.

As humans explore and settle in space, they will need to mine elements to support industries such as manufacturing and construction. In preparation for the establishment of permanent human settlements across the Solar System, we conducted the ESA BioRock experiment on board the International Space Station to investigate whether biological mining could be accomplished under extraterrestrial gravity conditions. We tested the hypothesis that the gravity (g) level influenced the efficacy with which biomining could be achieved from basalt, an abundant material on the Moon and Mars, by quantifying bioleaching by three different microorganisms under microgravity, simulated Mars and Earth gravitational conditions. One element of interest in mining is vanadium (V), which is added to steel to fabricate high strength, corrosion-resistant structural materials for buildings, transportation, tools and other applications. The results showed that Sphingomonas desiccabilis and Bacillus subtilis enhanced the leaching of vanadium under the three gravity conditions compared to sterile controls by 184.92 to 283.22%, respectively. Gravity did not have a significant effect on mean leaching, thus showing the potential for biomining on Solar System objects with diverse gravitational conditions. Our results demonstrate the potential to use microorganisms to conduct elemental mining and other bioindustrial processes in space locations with non-1 × g gravity. These same principles apply to extraterrestrial bioremediation and elemental recycling beyond Earth.

“Allocation at the point of substitution” applied to recycled rare earth elements: what can we learn?

Partitioning is often recommended as allocation procedure in attributional Life Cycle Assessments (a-LCAs). However, little guidance is available on how to apply partitioning to recycled products. This paper aims to demonstrate and discuss the application of the allocation procedure allocation at the point of substitution (APOS) via an evaluation of the impacts of the recycled phosphor yttrium europium oxide (YOX) from end-of-life fluorescent lamps. Starting from a multifunctional recycling process, APOS is applied by (1) identifying the products of the foreground sub-system, (2) identifying the origin of the recycled waste, (3) defining the boundaries of the production systems, and (4) applying economic allocation. It appears that recycled YOX is accountable for lower impacts than primary YOX for most impact categories. The largest contributor to the impacts of recycled YOX are the impacts related to the primary production of the fluorescent lamp, such as the use of mercury in the lamp tube. Even if this can be counter-intuitive to accept—as these impacts seem unrelated to YOX—these results provide useful information on whether the supply route of rare earth elements (REEs) from end-of-life fluorescent lamps is “future proof,” regarding potential (supply) risks due to environmental impacts upstream in the product supply chain. The application of APOS is demonstrated on the end-of-life recycling of rare earth elements. APOS provides the user of the recycled REE information about environmental impacts upstream in the product’s value chain. This could inform about the sustainability of the company’s operations—i.e., whether the future use or production of a material might be compromised due to (regulations to decrease) environmental impacts.

Subduction: The recycling engine room for global metallogeny

The formation of ore deposits, within mineral systems that represent highly anomalous concentrations of economic elements in localized parts of the Earth’s crust, first requires an enriched and available source of those elements. In early Earth history, initial enrichment in the upper mantle was arguably through mantle plumes that even recycled metals from the core-mantle boundary. From the Mesoarchean onwards, the development of plate tectonics allowed subduction processes to be increasingly important in both recycling of elements from the upper mantle into the lower crust and from there into the upper crust where mineral deposits could form and be exploited. The most obvious expression of this recycling process is the direct association of porphyry-high-sulfidation epithermal-skarn Cu-Au-Ag +/- Mo systems and inboard fractionated granite-associated Sn-W systems with magmatic-hydrothermal fluids derived from subduction-related magmas in convergent margins, where epithermal Au-Ag systems also developed due to high thermal gradients. Syn-subduction VMS Cu-Zn-Pb(Au) systems were accreted at convergent margins. Most orogenic gold systems relate to fluids released through devolatilization of down-going subduction slabs and overlying metal-rich sediment wedges. More indirect associations relate to the ability of subduction zones to cause structural damage and metasomatize and fertilize sub-continental mantle lithosphere along the margins of bordering craton margins. Orogen collapse in the final stages of the subduction-related orogenic event led to asthenosphere upwelling and formation of proximal intrusion-related and more distal Carlin-type gold systems in continental basins on the craton margins. During subsequent orogenic events, previously metasomatized and fertilized mantle lithosphere was reactivated to release hydrothermal fluids to form many of the orogenic gold systems in eastern China. Reactivation of the metasomatized lithosphere also resulted in development of post-subduction hybrid or alkaline magmas that generated giant magmatic Kiruna-type Fe-P, carbonatite-related REE-Nb or Cu-P, and lamproite-related diamond systems, together with magmatic-hydrothermal IOCG mineral systems near craton margins. Subduction-damaged craton margins and their rift-related marginal basins became the sites of formation of Zambian Copper Belt-type deposits and the craton margins were reactivated during subsequent rifting allowing intrusion of giant Ni-Cu mafic–ultramafic bodies along lithosphere-tapping fault zones at those margins. Thus, subduction acts as the recycling engine room or factory responsible for many of the global giant mineral systems that are currently exploited.

A cleaner strategy for comprehensive recovery of waste SmCo magnets based on deep eutectic solvents

Sustainable and comprehensive recycling of valuable elements from waste SmCo magnets is crucial. In this work, an environmentally friendly process based on low viscosity and easy preparation of hydrophobic deep eutectic solvent (HDES) for comprehensive recovery of Fe(III), Co(II), Cu(II) and Sm(III) from waste SmCo magnets has been developed. The HDESs based on dodecanol (Dodec) and tri-n-octylphosphine oxide (TOPO) were prepared, characterized and first used to selectively extract Fe(III) and Sm(III) from the SmCo magnets leachate. And then the Cu(II) and Co(II) in the raffinate were selectively separated using decanoic acid (DA):lauric acid (LA) (2:1) based HDES. The batch counter current extraction experiment was carried out under optimal conditions. After two-stage extraction by using Dodec:TOPO (2:1) based HDES, over 99% of the Fe(III) and Sm(III) were extracted into the organic phase. Subsequently, the raffinate containing Co(II) and Cu(II) was subjected to single-stage extraction and three-stage scrubbing using DA:LA (2:1) based HDES. Fe(III) and Sm(III) loaded in the Dodec:TOPO (2:1) based HDES phase could be stripped by using 1.5 mol/L H2C2O4. The obtained Fe2(C2O4)3 solution and Sm2(C2O4)3 precipitate were separated by filtration. And the Cu(II) loaded in the DA:LA (2:1) based HDES phase was stripped by using 1 mol/L H2SO4. Finally, Fe(III), Co(II), Cu(II) and Sm(III) were completely separated, and the purity of each product can reach 98.50% or higher. The recovery rates of Fe(III), Co(II), Cu(II) and Sm(III) were 99%, 99%, 96.47% and 99%, respectively. The process has lower chemical consumption and no need to use volatile and toxic organic solvent, which is conducive to cleaner and safer production.

Exchanges of major elements in a deciduous forest canopy

Forest canopy is a complex interface between the atmosphere, the biosphere and the lithosphere, exerting a strong influence on forest durability through element recycling. Leaves are filters of the low atmosphere and can capture dry deposition (DD). Trees have developed strategies, such as resorption (R) during senescence, for nutrient conservation. These strategies seem to depend on the soil type. The chemical composition evolution of leaves is conceptualized as a function of four fluxes: foliar absorption (FA) foliar leaching, (FL), accretion (A), and resorption (R). The objective of this study is to evaluate these five fluxes, i.e., DD, FA, FL, A, and R for different elements (N, P, K, S, Ca, Mg, Mn, and Si) at the experimental forest site in Montiers which includes three plots with contrasting soils and similar climate and stand characteristics. The percentage of resorption was 63% for N, 37% for S, 35% for K and 23% for P, regardless of the soil type. Resorption represents the most efficient recycling mechanism for ecosystems. Accretion during senescence occurs in two elements that are also found as biominerals in leaves: Ca (13–26 kg.ha−1.y−1) and Si (3–6 kg.ha−1.y−1). The effect of soil is limited to leaf concentrations and exchanges, and only for three elements (Mn, Ca and Si) that are not growth-limiting elements in our study site. This study shows that, except for N, taking into account the exchanges between living foliar tissues and leaching solutions is fundamental to accurately estimate the resorption rate.

Monte Carlo methods for numerical simulations of the Lead-Cooled Fast Reactor

Closed nuclear fuel cycle is one of the most promising options for the efficient use of nuclear energy resources with full recycling of long-lived transuranic elements. However, it can be implemented only in fast breeder reactors of Generation IV. The paper shows our methodology applied in the analysis of the lead-cooled fast reactor equilibrium fuel cycle using the Continuous Energy Monte Carlo Burnup Code – MCB. The implementation of novel modules for nuclear transmutation trajectory folding allows us to trace the life cycle of crucial minor actinides from the beginning of the reactor’s life towards the state of adiabatic equilibrium. Changes in the mass contribution to gateway isotopes 242Pu, 243Am and 244Cm during 124.2 years were considered in the study. Numerical demonstration was performed for the reactor core designed within the European Lead-cooled System (ELSY) project and redefined in the follow-up Lead-cooled European Advanced Demonstration Reactor (LEADER) project.

Construcción con Pallets

<p>Se busca dar una solución a la necesidad acuciante de sectores que no podrían acceder a viviendas por otros medios a la vez que propicia un sistema de reciclado y refuncionalización de elementos residuales de la industria de la construcción.</p><p>Capacitando para la construcción de módulos habitables, a partir de paneles realizados con Pallets de madera recuperados como residuos de obras de construcción.</p><p>Este desarrollo propone la construcción con un costo TENDIENDO A CERO ($ 0)</p><p>En una primera etapa la realización de un techo autoportante.</p><p>Se capacita por cursos presenciales en la zona, San Vicente, A.Korn, Villa Castells en La Plata, y actualmente en el 2020 motivados por el COVID-19 de forma virtual con unos 100 vecinos de las localidades de Magdalena, Coronel Brandsen y Chascomús, distantes las primeras unos 40 km y la ultima unos 75 km de La Plata.</p>

Spatial modeling and dynamics of organic matter biodegradation in the absence or presence of bacterivorous grazing

Biodegradation is a pivotal natural process for elemental recycling and preservation of an ecosystem. Mechanistic modeling of biodegradation has to keep track of chemical elements via stoichiometric theory, under which we propose and analyze a spatial movement model in the absence or presence of bacterivorous grazing. Sensitivity analysis shows that the organic matter degradation rate is most sensitive to the grazer’s death rate when the grazer is present and most sensitive to the bacterial death rate when the grazer is absent. Therefore, these two death rates are chosen as the primary parameters in the conditions of most mathematical theorems. The existence, stability and persistence of solutions are proven by applying linear stability analysis, local and global bifurcation theory, and the abstract persistence theory. Through numerical simulations, we obtain the transient and asymptotic dynamics and explore the effects of all parameters on the organic matter decomposition. Grazers either facilitate biodegradation or has no impact on biodegradation, which resolves the “decomposition–facilitation paradox” in the spatial context.

Elements of disease in a changing world: modelling feedbacks between infectious disease and ecosystems.

An overlooked effect of ecosystem eutrophication is the potential to alter disease dynamics in primary producers, inducing disease-mediated feedbacks that alter net primary productivity and elemental recycling. Models in disease ecology rarely track organisms past death, yet death from infection can alter important ecosystem processes including elemental recycling rates and nutrient supply to living hosts. In contrast, models in ecosystem ecology rarely track disease dynamics, yet elemental nutrient pools (e.g. nitrogen, phosphorus) can regulate important disease processes including pathogen reproduction and transmission. Thus, both disease and ecosystem ecology stand to grow as fields by exploring questions that arise at their intersection. However, we currently lack a framework explicitly linking these disciplines. We developed a stoichiometric model using elemental currencies to track primary producer biomass (carbon) in vegetation and soil pools, and to track prevalence and the basic reproduction number (R0 ) of a directly transmitted pathogen. This model, parameterised for a deciduous forest, demonstrates that anthropogenic nutrient supply can interact with disease to qualitatively alter both ecosystem and disease dynamics. Using this element-focused approach, we identify knowledge gaps and generate predictions about the impact of anthropogenic nutrient supply rates on infectious disease and feedbacks to ecosystem carbon and nutrient cycling.