•Ecological engineers have largely focused on landscape retention systems for P management.•Ecological engineering can play a broader role that supports a circular P economy.•Several ecological ...engineering approaches to P recovery and recycling have emerged.•Many strategies show promise for producing recovered P fertilizer and co-benefits, but challenges remain.•A systems framework is outlined that can guide research on P recovery and recycling.
Phosphorus is essential to life on Earth and frequently limits the productivity of ecosystems, including agroecosystems. Currently, a substantial portion of the global human population relies on finite phosphate rock resources used for chemical fertilizer production. Concern over poor management of these vital resources and continued efforts to enhance soil fertility and food security have stimulated interest in phosphorus recovery and recycling. Existing heterogeneity in phosphorus waste flows, agricultural phosphorus needs, the availability of resources, and spatial patterns of land use calls for a diverse array of phosphorus recycling strategies. Ecological engineers working on phosphorus management have most commonly aimed to create phosphorus sinks on the landscape to help mitigate eutrophication. There is a growing need for ecological engineering approaches that go beyond phosphorus retention to create pathways for phosphorus recovery and recycling, supporting both eutrophication control and food security. This review includes a brief overview of human impacts on the global phosphorus cycle and a survey of existing ecological engineering techniques for phosphorus recovery and recycling discussed in the literature. A systems approach for design and feasibility assessment of phosphorus recycling with eco-technology is outlined, along with several key challenges. The importance of an interdisciplinary, multiple element, and multiple resource approach to phosphorus recycling is emphasized.
Improving diet quality while simultaneously reducing environmental impact is a critical focus globally. Metrics linking diet quality and sustainability have typically focused on a limited suite of ...indicators, and have not included food waste. To address this important research gap, we examine the relationship between food waste, diet quality, nutrient waste, and multiple measures of sustainability: use of cropland, irrigation water, pesticides, and fertilizers. Data on food intake, food waste, and application rates of agricultural amendments were collected from diverse US government sources. Diet quality was assessed using the Healthy Eating Index-2015. A biophysical simulation model was used to estimate the amount of cropland associated with wasted food. This analysis finds that US consumers wasted 422g of food per person daily, with 30 million acres of cropland used to produce this food every year. This accounts for 30% of daily calories available for consumption, one-quarter of daily food (by weight) available for consumption, and 7% of annual cropland acreage. Higher quality diets were associated with greater amounts of food waste and greater amounts of wasted irrigation water and pesticides, but less cropland waste. This is largely due to fruits and vegetables, which are health-promoting and require small amounts of cropland, but require substantial amounts of agricultural inputs. These results suggest that simultaneous efforts to improve diet quality and reduce food waste are necessary. Increasing consumers' knowledge about how to prepare and store fruits and vegetables will be one of the practical solutions to reducing food waste.
A major challenge in theoretical ecology is understanding how natural microbial communities support species diversity, and in particular how antibiotic-producing, -sensitive and -resistant species ...coexist. While cyclic ‘rock–paper–scissors’ interactions can stabilize communities in spatial environments, coexistence in unstructured environments remains unexplained. Here, using simulations and analytical models, we show that the opposing actions of antibiotic production and degradation enable coexistence even in well-mixed environments. Coexistence depends on three-way interactions in which an antibiotic-degrading species attenuates the inhibitory interactions between two other species. These interactions enable coexistence that is robust to substantial differences in inherent species growth rates and to invasion by ‘cheating’ species that cease to produce or degrade antibiotics. At least two antibiotics are required for stability, with greater numbers of antibiotics enabling more complex communities and diverse dynamic behaviours ranging from stable fixed points to limit cycles and chaos. Together, these results show how multi-species antibiotic interactions can generate ecological stability in both spatially structured and mixed microbial communities, suggesting strategies for engineering synthetic ecosystems and highlighting the importance of toxin production and degradation for microbial biodiversity.
Classical theory shows that large communities are destabilized by random interactions among species pairs, creating an upper bound on ecosystem diversity. However, species interactions often occur in ...high-order combinations, whereby the interaction between two species is modulated by one or more other species. Here, by simulating the dynamics of communities with random interactions, we find that the classical relationship between diversity and stability is inverted for high-order interactions. More specifically, while a community becomes more sensitive to pairwise interactions as its number of species increases, its sensitivity to three-way interactions remains unchanged, and its sensitivity to four-way interactions actually decreases. Therefore, while pairwise interactions lead to sensitivity to the addition of species, four-way interactions lead to sensitivity to species removal, and their combination creates both a lower and an upper bound on the number of species. These findings highlight the importance of high-order species interactions in determining the diversity of natural ecosystems.
A key aspect of bacterial survival is the ability to evolve while migrating across spatially varying environmental challenges. Laboratory experiments, however, often study evolution in well-mixed ...systems. Here, we introduce an experimental device, the microbial evolution and growth arena (MEGA)-plate, in which bacteria spread and evolved on a large antibiotic landscape (120×60 centimeters) that allowed visual observation of mutation and selection in a migrating bacterial front. While resistance increased consistently, multiple coexisting lineages diversified both phenotypically and genotypically. Analyzing mutants at and behind the propagating front, we found that evolution is not always led by the most resistant mutants; highly resistant mutants may be trapped behind more sensitive lineages. The MEGA-plate provides a versatile platform for studying microbial adaption and directly visualizing evolutionary dynamics.
There is an urgent need to assess the linkages between diet patterns and environmental sustainability in order to meet global targets for reducing premature mortality and improving sustainable ...management of natural resources. This study fills an important research gap by evaluating the relationship between incremental differences in diet quality and multiple environmental burdens, while also accounting for the separate contributions of retail losses, inedible portions, and consumer waste. Cross sectional, nationally-representative data on food intake in the United States were acquired from the National Health and Nutrition Examination Survey (2005-2016), and were linked with nationally-representative data on food loss and waste from published literature. Survey-weighted procedures estimated daily per capita food retail loss, food waste, inedible portions, and consumed food, and were summed to represent Total Food Demand. Diet quality was measured using the Healthy Eating Index-2015 and the Alternative Healthy Eating Index-2010. Data on food intake, loss, and waste were inputted into the US Foodprint Model to estimate the amount of agricultural land, fertilizer nutrients, pesticides, and irrigation water used to produce food. This study included dietary data from 50,014 individuals aged greater than or equai to2 y. Higher diet quality (HEI-2015 and AHEI-2010) was associated with greater per capita Total Food Demand, as well as greater retail loss, inedible portions, consumer waste, and consumed food (P < 0.001 for all comparisons). Consumed food accounted for 56-74% of agricultural resource use (land, fertilizer nutrients, pesticides, and irrigation water), retail loss accounted for 4-6%, inedible portions accounted for 2-15%, and consumer waste accounted for 20-23%. Higher diet quality was associated with lower use of agricultural land, but the relationship to other agricultural resources was dependent on the tool used to measure diet quality (HEI-2015 vs. AHEI-2010). Over one-quarter of the agricultural inputs used to produce Total Food Demand were attributable to edible food that was not consumed. Importantly, this study also demonstrates that the relationship between diet quality and environmental sustainability depends on how diet quality is measured. These findings have implications for the development of sustainable dietary guidelines, which requires balancing population-level nutritional needs with the environmental impacts of food choices.
•Anaerobic digesters processing dairy manure and food waste produce solid residues.•Digestate solids were tested as substrate ingredients in P. ostreatus cultivation.•Substrate recipes including 15% ...digestate solids by dry matter produced high yields.•Much N and P recovered in mushrooms, leaving useful spent mushroom substrate.•Mushroom cultivation can divert nutrients into edible food without land application.
State-level policies in the New England region of the United States require diversion of organic materials away from landfills. One management option for food waste is anaerobic co-digestion with dairy manure. In addition to biogas, anaerobic digestion produces separated solid and liquid digestates. Solid digestates in the region are typically recycled as animal bedding before returning to the digester and liquids are used to fertilize local soils. Repeated land application of nutrients can contribute to eutrophication risk over time and alternative models are needed to convert digestates into valuable export products. We tested solid digestates derived from dairy manure and food waste as substrate ingredients in the cultivation of Pleurotus ostreatus. We show these materials can be used to offset non-local substrate ingredients while achieving mushroom yields comparable to commercial recipes. This strategy could help divert nutrients away from land adjacent to digesters and into safe, protein-rich food, while producing useful spent mushroom substrate.
Sodium-glucose cotransporter 2 (SGLT2) inhibitors are a novel class of antihyperglycemic agents that improve glycemic control by increasing glycosuria. Additional benefits beyond glucose lowering ...include significant improvements in seated clinic blood pressure (BP), partly attributed to their diuretic-like actions. Less known are the effects of this class on 24-hour ambulatory BP, which is a better predictor of cardiovascular risk than seated clinic BP.
We performed a meta-analysis of randomized, double-blind, placebo-controlled trials to investigate the effects of SGLT2 inhibitors on 24-hour ambulatory BP. We searched all studies published before August 17, 2016, which reported 24-hour ambulatory BP data. Mean differences in 24-hour BP, daytime BP, and nighttime BP were calculated by a random-effects model. SGLT2 inhibitors significantly reduce 24-hour ambulatory systolic and diastolic BP by -3.76 mm Hg (95% CI, -4.23 to -2.34; I
=0.99) and -1.83 mm Hg (95% CI, -2.35 to -1.31; I
=0.76), respectively. Significant reductions in daytime and nighttime systolic and diastolic BP were also found. No association between baseline BP or change in body weight were observed.
This meta-analysis shows that the reduction in 24-hour ambulatory BP observed with SGLT2 inhibitors is a class effect. The diurnal effect of SGLT2 inhibitors on 24-hour ambulatory BP may contribute to their favorable effects on cardiovascular outcomes.
Overall dietary energy intake, particularly the consumption of simple sugars such as fructose, has been increasing steadily in Western societies, but the effects of such diets on the brain are poorly ...understood. Here, we used functional and structural assays to characterize the effects of excessive caloric intake on the hippocampus, a brain region important for learning and memory. Rats fed with a high‐fat, high‐glucose diet supplemented with high‐fructose corn syrup showed alterations in energy and lipid metabolism similar to clinical diabetes, with elevated fasting glucose and increased cholesterol and triglycerides. Rats maintained on this diet for 8 months exhibited impaired spatial learning ability, reduced hippocampal dendritic spine density, and reduced long‐term potentiation at Schaffer collateral—CA1 synapses. These changes occurred concurrently with reductions in levels of brain‐derived neurotrophic factor in the hippocampus. We conclude that a high‐calorie diet reduces hippocampal synaptic plasticity and impairs cognitive function, possibly through BDNF‐mediated effects on dendritic spines. Published 2008 Wiley‐Liss, Inc.
A dominant histopathological feature in neuromuscular diseases, including amyotrophic lateral sclerosis and inclusion body myopathy, is cytoplasmic aggregation of the RNA-binding protein TDP-43. ...Although rare mutations in TARDBP-the gene that encodes TDP-43-that lead to protein misfolding often cause protein aggregation, most patients do not have any mutations in TARDBP. Therefore, aggregates of wild-type TDP-43 arise in most patients by an unknown mechanism. Here we show that TDP-43 is an essential protein for normal skeletal muscle formation that unexpectedly forms cytoplasmic, amyloid-like oligomeric assemblies, which we call myo-granules, during regeneration of skeletal muscle in mice and humans. Myo-granules bind to mRNAs that encode sarcomeric proteins and are cleared as myofibres mature. Although myo-granules occur during normal skeletal-muscle regeneration, myo-granules can seed TDP-43 amyloid fibrils in vitro and are increased in a mouse model of inclusion body myopathy. Therefore, increased assembly or decreased clearance of functionally normal myo-granules could be the source of cytoplasmic TDP-43 aggregates that commonly occur in neuromuscular disease.
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