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Numerous biotic mechanisms can control ecosystem nutrient cycling, but their full incorporation into ecological models or experimental designs can result in inordinate complexity. Including organismal nutrient limitation in models of highly dimensional systems (i.e., those with many nutrient pools/species) presents a critical challenge. We evaluate the importance of explicitly considering microbial and animal nutrient limitation to predict ecosystem nitrogen cycling across plant-based and detritus-based food chains. We investigate how eight factorial scenarios of microbial, herbivore, and microbi-detritivore (i.e., omnivores consuming microbes and detritus) nitrogen or carbon limitation alter the stocks and flows of nitrogen in an ecosystem model. We used a combination of partial derivatives of model equilibrium solutions and numerical simulations using randomly drawn parameter sets to explore the impact of each nutrient limitation scenario on nutrient stocks and flows. We show that switching microbes, herbivores, or microbi-detritivores from nitrogen to carbon limitation consistently altered the ecosystem response to changes in inorganic nitrogen supply, plant C:N ratio, and microbial C:N ratio. Organism nutrient limitation changed ecosystem nitrogen flows by altering the feedbacks between the abiotic and biotic pools. For example, microbi-detritivore nutrient limitation determined whether the microbial response to changes in inorganic nitrogen supply and C:N ratios was dependent on the size of detrital carbon or detrital nitrogen pool. Such correlated responses among biotic and abiotic pools set up a network of predictable changes in ecosystem properties sensitive to organism nutrient limitation. Scenarios with microbial limitation were generally sufficient to capture the suite of ecosystem responses to increasing inorganic nitrogen supply, while scenarios with animal limitation added new behavior whenever C:N ratios changed. We make the case for explicitly considering both microbial and animal nutrient limitation when predicting the flow and distribution of nitrogen across green and brown food chains.

Most of the earth's terrestrial species live in the soil. These organisms, which include many thousands of species of fungi and nematodes, shape aboveground plant and animal life as well as our climate and atmosphere. Indeed, all terrestrial ecosystems consist of interdependent aboveground and belowground compartments. Despite this, aboveground and belowground ecology have been conducted largely in isolation. This book represents the first major synthesis to focus explicitly on the connections between aboveground and belowground subsystems--and their importance for community structure and ecosystem functioning. David Wardle integrates a vast body of literature from numerous fields--including population ecology, ecosystem ecology, ecophysiology, ecological theory, soil science, and global-change biology--to explain the key conceptual issues relating to how aboveground and belowground communities affect one another and the processes that each component carries out. He then applies these concepts to a host of critical questions, including the regulation and function of biodiversity as well as the consequences of human-induced global change in the form of biological invasions, extinctions, atmospheric carbon-dioxide enrichment, nitrogen deposition, land-use change, and global warming. Through ambitious theoretical synthesis and a tremendous range of examples, Wardle shows that the key biotic drivers of community and ecosystem properties involve linkages between aboveground and belowground food webs, biotic interaction, the spatial and temporal dynamics of component organisms, and, ultimately, the ecophysiological traits of those organisms that emerge as ecological drivers. His conclusions will propel theoretical and empirical work throughout ecology.

Resistance to 3rd-generation cephalosporins in Escherichia coli is mostly mediated by extended-spectrum beta-lactamases (ESBLs) or AmpC beta-lactamases. Besides overexpression of the species-specific chromosomal ampC gene, acquisition of plasmid-encoded ampC genes, e.g. bla , has been described worldwide in E. coli from humans and animals. To investigate a possible transmission of bla along the food production chain, we conducted a next-generation sequencing (NGS)-based analysis of 164 CMY-2-producing E. coli isolates from humans, livestock animals and foodstuff from Germany. The data of the 164 sequenced isolates revealed 59 different sequence types (STs); the most prevalent ones were ST38 (n = 19), ST131 (n = 16) and ST117 (n = 13). Two STs were present in all reservoirs: ST131 (human n = 8; food n = 2; animal n = 6) and ST38 (human n = 3; animal n = 9; food n = 7). All but one CMY-2-producing ST131 isolates belonged to the clade B (fimH22) that differed substantially from the worldwide dominant CTX-M-15-producing clonal lineage ST131-O25b clade C (fimH30). Plasmid replicon types IncI1 (n = 61) and IncK (n = 72) were identified for the majority of bla -carrying plasmids. Plasmid sequence comparisons showed a remarkable sequence identity, especially for IncK plasmids. Associations of replicon types and distinct STs were shown for IncK and ST57, ST429 and ST38 as well as for IncI1 and ST58. Additional β-lactamase genes (bla , bla , bla , bla ) were detected in 50% of the isolates, and twelve E. coli from chicken and retail chicken meat carried the colistin resistance gene mcr-1. We found isolates of distinct E. coli clonal lineages (ST131 and ST38) in all three reservoirs. However, a direct clonal relationship of isolates from food animals and humans was only noticeable for a few cases. The CMY-2-producing E. coli-ST131 represents a clonal lineage different from the CTX-M-15-producing ST131-O25b cluster. Apart from the ST-driven spread, plasmid-mediated spread, especially via IncI1 and IncK plasmids, likely plays an important role for emergence and transmission of bla between animals and humans.

This paper reviews the literature on perishable food cold-chain management (FCCM) in order to assess its current state, pinpoint its knowledge gaps, and suggest a framework for addressing the issues faced by this industry. This work examines 103 academic articles on the topic of the perishable food supply chain published in various journals between 2001 and 2022. Research publications were selected from two reputed databases—Scopus and Web of Science. The study finds that the current trend in FCCM is toward sustainable FCCM, which offers financial, ecological, and social benefits. However, sustainable FCC practices are more common in wealthy nations but are still lacking in developing countries. High lead times, costs, waste, order returns, complaints, and dissatisfied consumers are the results of a fragmented market and the associated proliferation of chain intermediates. The authors have also developed a conceptual framework based on the findings that illustrates the interconnected nature of the food cold-chain facilities, collaboration among food cold-chain (FCC) stakeholders, concern among FCC stakeholders, economic enhancement, fulfilment of FCC stakeholders’ responsibilities, and overall functioning of the FCC. This study may be helpful to FCC professionals, food regulators, government authorities, and researchers because it gives a concise picture of the state of research in the field.

Improving the eco-efficiency of food systems is one of the major global challenges faced by the modern world. Short food supply chains (SFSCs) are commonly regarded to be less harmful to the environment, among various reasons, due to their organizational distribution and thus the shortened physical distance between primary producers and final consumers. In this paper, we empirically test this hypothesis, by assessing and comparing the environmental impacts of short and long food supply chains. Based on the Life Cycle Assessment (LCA) approach, we calculate eco-efficiency indicators for nine types of food distribution chains. The analysis is performed on a sample of 428 short and long food supply chains from six European countries. Our results indicate that, on average, long food supply chains may generate less negative environmental impacts than short chains (in terms of fossil fuel energy consumption, pollution, and GHG emissions) per kg of a given product. The values of eco-efficiency indicators display a large variability across analyzed chains, and especially across different types of SFSCs. The analysis shows that the environmental impacts of the food distribution process are not only determined by the geographical distance between producer and consumer, but depend on numerous factors, including the supply chain infrastructure.

Aflatoxins (AFs) are among the most harmful fungal secondary metabolites imposing serious health risks on both household animals and humans. The more frequent occurrence of aflatoxins in the feed and food chain is clearly foreseeable as a consequence of the extreme weather conditions recorded most recently worldwide. Furthermore, production parameters, such as unadjusted variety use and improper cultural practices, can also increase the incidence of contamination. In current aflatoxin control measures, emphasis is put on prevention including a plethora of pre-harvest methods, introduced to control infestations and to avoid the deleterious effects of aflatoxins on public health. Nevertheless, the continuous evaluation and improvement of post-harvest methods to combat these hazardous secondary metabolites are also required. Already in-use and emerging physical methods, such as pulsed electric fields and other nonthermal treatments as well as interventions with chemical agents such as acids, enzymes, gases, and absorbents in animal husbandry have been demonstrated as effective in reducing mycotoxins in feed and food. Although most of them have no disadvantageous effect either on nutritional properties or food safety, further research is needed to ensure the expected efficacy. Nevertheless, we can envisage the rapid spread of these easy-to-use, cost-effective, and safe post-harvest tools during storage and food processing.

Fungal diseases threaten natural and man-made ecosystems. Chytridiomycota (chytrids) infect a wide host range, including phytoplankton species that form the basis of aquatic food webs and produce roughly half of Earth’s oxygen. However, blooms of large or toxic phytoplankton form trophic bottlenecks, as they are inedible to zooplankton. Chytrids infecting inedible phytoplankton provide a trophic link to zooplankton by producing edible zoospores of high nutritional quality. By grazing chytrid zoospores, zooplankton may induce a trophic cascade, as a decreased zoospore density will reduce new infections. Conversely, fewer infections will not produce enough zoospores to sustain long-term zooplankton growth and reproduction. This intricate balance between zoospore density necessary for zooplankton energetic demands (growth/survival), and the loss in new infections (and thus new zoospores) because of grazing was tested empirically. To this end, we exposed a cyanobacterial host (Planktothrix rubescens) infected by a chytrid (Rizophydium megarrhizum) to a grazer density gradient (the rotifer Keratella cf. cochlearis). Rotifers survived and reproduced on a zoospore diet, but the Keratella population growth was limited by the amount of zoospores provided by chytrid infections, resulting in a situation where zooplankton survived but were restricted in their ability to control disease in the cyanobacterial host. We subsequently developed and parameterized a dynamical food-chain model using an allometric relationship for clearance rate to assess theoretically the potential of different-sized zooplankton groups to restrict disease in phytoplankton hosts. Our model suggests that smaller-sized zooplankton may have a high potential to reduce chytrid infections on inedible phytoplankton. Together, our results point out the complexity of three-way interactions between hosts, parasites, and grazers and highlight that trophic cascades are not always sustainable and may depend on the grazer’s energetic demand.

Substances that accumulate to hazardous levels in living organisms pose environmental and human-health risks, which governments seek to reduce or eliminate. Regulatory authorities identify bioaccumulative substances as hydrophobic, fat-soluble chemicals having high octanol-water partition coefficients (KOW)(>=100,000). Here we show that poorly metabolizable, moderately hydrophobic substances with a KOW between 100 and 100,000, which do not biomagnify (that is, increase in chemical concentration in organisms with increasing trophic level) in aquatic food webs, can biomagnify to a high degree in food webs containing air-breathing animals (including humans) because of their high octanol-air partition coefficient (KOA) and corresponding low rate of respiratory elimination to air. These low KOW-high KOA chemicals, representing a third of organic chemicals in commercial use, constitute an unidentified class of potentially bioaccumulative substances that require regulatory assessment to prevent possible ecosystem and human-health consequences.

We present a framework to explain how prey stress responses to predation can resolve context dependency in ecosystem properties and functions such as food chain length, secondary production, elemental stoichiometry, and cycling. We first describe the major nonspecific physiological stress mechanisms and their ecologically relevant consequences. We next synthesize the evidence for prey physiological responses to predation risk and demonstrate that they are similar across taxa and fit well within the general stress paradigm. We then illustrate the utility of our idea by applying our understanding of the ecological consequences of stress to explain how herbivore‐prey physiological antipredator responses affect ecosystem dynamics. We hypothesize that stressed herbivores should forage on plant species with higher digestible carbohydrates than should unstressed herbivores to meet heightened energy demands. Increased consumption of carbohydrate‐rich plants should reduce their relative abundance in the community, hence altering the quantity and quality of plant litter entering the detrital pool. We further hypothesize that stress should change the elemental composition and energy content of prey excreta, egesta, and carcasses that enter the detrital pool. Finally, prey stress should lower energy and nutrient conversion efficiency and hence the transfer of materials and energy up the food chain, which should, in turn, weaken the association between ecosystem productivity and food chain length.