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1.
Sci Total Environ ; 753: 141902, 2021 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-33207459

RESUMO

One of negative side-effects of usage of bio-renewables might be generation of mineral (ash) material, potential source of environmental pollution. A hypothesis was that bottom ash (BA; from biomass cogeneration facility) could be efficiently (re) used in soil chemical conditioning similarly to widely-used dolomite-based soil conditioner (DO; from Croatian Dinaric-coastal region) which we tested by: i) physicochemical characterisation of BA and DO, and ii) bioassay with Raphanus sativus cultivated in acidic soil amended with BA or DO. Scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) confirmed complex chemical/physical structures and morphology between amendments, X-ray diffraction (XRD) showed their distinctive mineralogy with predominantly dolomite (in DO) vs. quartz and calcite (in BA), while secondary ion mass spectrometry (SIMS) revealed their diverse elemental/isotopic composition. The BA or DO amendments ameliorated soil acidity, increased available P, K and most other nutrients, but not Cd. The BA or DO amendments improved vegetative growth and edible hypocotyl yield. However, both amendments also increased Cd accumulation in all radish tissues, which was unexpected given the alkaline matrix of bio-ash and dolomite that would be likely to facilitate retention and immobilisation of toxic Cd. Thus, thorough characterisation and evaluation of BA- and/or DO-based materials and relevant soils (with an emphasis on metal sorption/immobilisation) prior to application in (agro) ecosystems is crucial for producing food clean of toxic metals.


Assuntos
Raphanus , Poluentes do Solo , Biomassa , Cádmio/análise , Carbonato de Cálcio , Cinza de Carvão , Ecossistema , Magnésio , Nutrientes , Solo , Poluentes do Solo/análise
2.
Chemosphere ; 262: 127820, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32781332

RESUMO

In this study, the behavior of mono-component (metronidazole/phosphate/nitrate, MET/PO43-/NO3-) and multi-component (MET+PO43-+NO3-) adsorption in fixed-bed adsorption column was investigated using Prosopis juliflora activated carbon (PJAC). The influence of column operating parameters such as bed depth (H: 5-15 cm), influent flow rate (Q: 0.5-2 L/h) and adsorbate concentration (Co: 25-100 mg/L) on breakthrough curves were evaluated. The experimental data was correlated with breakthrough models viz. Thomas, Adams-Bohart, Yoon-Nelson and bed depth service time (BDST) models. The results showed that the Thomas model fitted the experimental data better than other models in predicting the breakthrough characteristics for the removal of MET, PO43- and NO3- by PJAC. The maximum adsorption capacity found by Thomas model was 9.70, 8.21 and 5.57 mg/g for MET, PO43- and NO3-, respectively. In multi-component systems, antagonistic behavior in sorption of MET, PO43- and NO3- was observed and as a result, adsorption capacity was 1.2-1.5 folds lesser than that observed in mono-component system. In conclusion, results of the present study indicate that the PJAC can be successfully employed for the removal of MET, PO43- and NO3- using fixed-bed adsorption column; however, the column design for multi-component mixture should be based on rapid breakthrough sorbate.


Assuntos
Carvão Vegetal/química , Prosopis , Poluentes Químicos da Água/química , Purificação da Água/métodos , Adsorção , Antibacterianos , Nutrientes , Poluentes Químicos da Água/análise
3.
Chemosphere ; 262: 127939, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33182115

RESUMO

Species specific nitrogen-to-phosphorus molar ratio (NPR) has been suggested for green microalgae. Algae can store nitrogen and phosphorus, suggesting that the optimum feed concentration dynamically changes as function of the nutrient storage. We assessed the effect of varying influent NPR on microalgal cultivation in terms of microbial community stability, effluent quality and biokinetics. Mixed green microalgae (Chlorella sorokiniana and Scenedesmus sp.) and a monoculture of Chlorella sp. were cultivated in continuous laboratory-scale reactors treating used water. An innovative image analysis tool, developed in this study, was used to track microbial community changes. Diatoms proliferated as influent NPR decreased, and were outcompeted once cultivation conditions were restored to the optimal NPR range. Low NPR operation resulted in decrease in phosphorus removal, biomass concentration and effluent nitrogen concentration. ASM-A kinetic model simulation results agreed well with operational data in the absence of diatoms. The failure to predict operational data in the presence of diatoms suggest differences in microbial activity that can significantly influence nutrient recovery in photobioreactors (PBR). No contamination occurred during Chlorella sp. monoculture cultivation with varying NPRs. Low NPR operation resulted in decrease in biomass concentration, effluent nitrogen concentration and nitrogen quota. The ASM-A model was calibrated for the monoculture and the simulations could predict the experimental data in continuous operation using a single parameter subset, suggesting stable biokinetics under the different NPR conditions. Results show that controlling the influent NPR is effective to maintain the algal community composition in PBR, thereby ensuring effective nutrients uptake.


Assuntos
Microalgas/fisiologia , Nitrogênio/análise , Fósforo/análise , Purificação da Água/métodos , Biomassa , Chlorella , Nutrientes , Fotobiorreatores , Scenedesmus , Águas Residuárias , Água
4.
Sci Total Environ ; 750: 141221, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32846250

RESUMO

Improved coastal management has decreased anthropogenic nutrient input over the past few decades, leading to phosphorus depletion. It has been hypothesized that phosphorus depletion in coastal environments leads to declines in macroalgae abundance. Perennial canopy-forming temperate macroalgae can experience the effects of limited phosphorus availability during seasonal phosphorus depletion periods. When nutrients are sufficient, they are stored in algal tissues after luxury uptake and are available to support growth during phosphorus-depleted conditions. Cultivation of mature and actively growing juvenile brown alga (Sargassum macrocarpum) under different nutrient conditions provided individuals with different tissue nutrient concentrations. The maximum photosynthetic rates of these individuals were examined under nutrient-depleted conditions to evaluate "storage capacity", which we defined as the amount of stored phosphorus that can support maximum growth. Maximum photosynthetic rate was used as a proxy for maximum growth rates. The experiments revealed that growth rates of juveniles increased when stored phosphorus content was high. In contrast, the maximum growth rates tended not to increase with an increase in stored phosphorus content in mature individuals. The phosphorus storage capacities for juvenile and mature individuals were approximately 19 and more than 16 weeks, respectively, suggesting that individual alga can endure several months of phosphorus depletion.


Assuntos
Fósforo , Sargassum , Humanos , Nitrogênio , Nutrientes , Fotossíntese
5.
Sci Total Environ ; 751: 141607, 2021 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-32871314

RESUMO

The emission of nutrients and pesticides from agricultural soils endangers natural habitats. Here, we review to which extent carbon-rich organic amendments help to retain nutrients and pesticides in agricultural soils and to reduce the contamination of surrounding areas and groundwater. We compare straw, compost, and biochar to see whether biochar outperforms the other two more traditional and cheaper materials. We present a list of criteria to evaluate the suitability of organic materials to be used as soil amendments and discuss differences in elemental compositions of straw, compost, and biochar to understand, how soil microorganisms utilize those materials. We review their effects on physical and chemical soil characteristics, soil microbial communities, as well as effects on the transformation and retention of nutrients and pesticides in detail. It becomes clear that for all three amendments their effects can vary greatly depending on numerous aspects, such as the type of soil, application rate, and production procedure of the organic material. Biochar is most effective in increasing the sorption capacity of soils but does not outperform straw and compost with regards to the other aspects investigated. Nevertheless, the possibility to design biochar properties makes it a very promising material. Finally, we provide critical comments about how to make studies about organic amendments more comparable (comprehensive provision of material properties), how to improve concepts of future work (meta-analysis, long-term field studies, use of deep-insight microbial DNA sequencing), and what needs to be further investigated (the link between structural and functional microbial parameters, the impact of biochar on pesticide efficiency).


Assuntos
Compostagem , Microbiota , Praguicidas , Poluentes do Solo , Carvão Vegetal , Nutrientes , Solo , Poluentes do Solo/análise
6.
Food Chem ; 336: 127668, 2021 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32758805

RESUMO

Hulled Reins and hulless Lamont oats were dehulled and/or sequentially abraded to produce ten pearling fines and corresponding pearled kernels. Contents of nutrients (protein, oil, starch, beta-glucan, ash and other carbohydrates) and avenanthramides (AVA) 2p, 2c, 2f, and 5p in processing fractions and starting grains were measured. Results show that distribution patterns of nutrients varied with individual nutrients, but those of AVAs varied with variety and individual AVAs. In both varieties, from the surface to inner endosperms, protein and oil increased then decreased; ash and other carbohydrates decreased; starch increased; and beta-glucan unchanged except for the surface area. In Lamont oat, the four AVAs decreased, but in Reins oat, AVA 2p decreased while 2c, 2f and 5p increased, then decreased. Compared to whole grain, pearled oats not only contained lower AVAs, protein, oil, ash, and other carbohydrates and higher beta-glucan and starch but also had a different AVA composition.


Assuntos
Avena/química , Sementes/química , ortoaminobenzoatos/análise , Nutrientes/análise , Proteínas de Vegetais Comestíveis/análise , Amido/análise , beta-Glucanas/análise
7.
Sci Total Environ ; 752: 141262, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32889253

RESUMO

This study evaluates spatiotemporal variability in the behavior of septic system derived nutrients in a sandy nearshore aquifer and their discharge to a large lake. A groundwater nutrient-rich plume was monitored over a two-year period with the septic system origin of the plume confirmed using artificial sweeteners. High temporal variability in NO3-N attenuation in the nearshore aquifer prior to discharge to the lake (42-96%) reveals the complex behavior of NO3-N and potential importance of changing hydrological and geochemical conditions in controlling NO3-N discharge to the lake. While PO4-P was retarded in the nearshore aquifer, the PO4-P plume extended over 90 m downgradient of the septic system. It was estimated that the PO4-P plume may reach the lake within 10 years and represents a legacy issue whereby PO4-P loads to the lake may increase over time. To provide broader assessment of the contribution of septic systems to P and N loads to a large lake, a regional scale geospatial model was developed that considers the locations of individual septic systems along the Canadian Lake Erie shoreline. The estimated P and N loads indicate that septic systems along the shoreline are only a minor contributor to the annual P and N loads to Lake Erie. However, it is possible that nutrients from septic systems may contribute to localized algal blooms in shoreline areas with high septic system density. In addition, disproportionate P and N loads in discharging groundwater may change the N:P ratio in nearshore waters and promote growth of harmful cyanobacteria. The study provides new insights into factors controlling the function of the reaction zone near the groundwater-lake interface including its impact on groundwater-derived nutrient inputs to large lakes. Further, the study findings are needed to inform septic system and nutrient management programs aimed at reducing lake eutrophication.


Assuntos
Água Subterrânea , Lagos , Canadá , Monitoramento Ambiental , Eutrofização , Nitrogênio/análise , Nutrientes , Fósforo/análise
8.
Sci Total Environ ; 752: 141747, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32889263

RESUMO

In water environment, nitrogen (N) and phosphorus (P) are biochemically dependent nutrients following the co-limitation concept for algae growth under mixotrophic mode. From a practical viewpoint, algae growth may not bring about significant change of the background nutrient concentration of an actual waterbody in contrast to a conventional batch system. In order to better understand the growth pattern of microalgae in aquatic environments, a series of experiments were conducted under stably controlled N-P levels for studying the N-P coupling effect on mixotrophic Chlorella vulgaris growth process, with attention paid to the physiological and biochemical characteristics. It was found that within the concentration range of N = 1-8 mg·L-1 and P = 0.1-1.0 mg·L-1, the variation of the N-P level slightly affected the specific growth rate, but significantly influenced nutrients uptake, biomass dry weight, chlorophyll contents of the grown C. vulgaris. The biochemical and elemental composition of the microalgae tended to be more sensitive to the N-P concentrations and ratios in the lower nutrient range (1-2 mg N·L-1, 0.1-0.4 mg P·L-1) in which the highest N and P conversion rates were gained as 90.18 ± 1.23% and 60.47 ± 1.59%, respectively. The P assimilation and conversion efficiencies were much affected by both N and P supplies, while the P supply showed little influence on N assimilation and conversion efficiencies. It was also noticed that the N level greatly affected the metabolic pathway involving nutrient assimilation, carbohydrate fixation and monosaccharide profile, resulting in conversion of the dominant fraction of protein at N ≤ 2 mg·L-1 into other biochemical compositions including lipids at N ≥ 3 mg·L-1. The fatty acid methyl esters (FAMEs) composition tended to differ with varied nutrient levels. These findings may deepen our understanding of algal growth in aquatic environment and provide perspective for eutrophication control.


Assuntos
Chlorella vulgaris , Microalgas , Biomassa , Nitrogênio , Nutrientes , Fósforo , Águas Residuárias
9.
Sci Total Environ ; 753: 141984, 2021 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-32906047

RESUMO

Sediment removal from eutrophicated shallow lakes may not only be an effective method for lake restoration but also provides the potential for recycling nutrients from sediments to crop production. However, finding a suitable strategy for sustainably reusing the sediment remains a challenge. Therefore, current study focused on the best practices in applying the sediment from a shallow eutrophicated lake to the soil in terms of grass yield, nutrient uptake, and nutrient leaching. During a nine-month lysimeter experiment, 100-cm high columns were filled with six combinations of soil, sediment, and biochar, with or without meat bone meal organic fertilizer. Aboveground biomass, root mass distribution in soil, nutrient concentration, phosphorus (P) uptake of perennial ryegrass (Lolium perenne L.) along with easily soluble nutrients in the growing medium, and leached mineral nitrogen (N) and P levels were measured. Plant growth conditions were improved by sediment additions, as the yield and P uptake of ryegrass nearly doubled in treatments containing sediment compared to the control soil. While the sediment was richer in macro and micronutrients (e.g. P and N) compared to the soil, the leached N and P levels from both treatments were almost equivalent (N < 830 mg m-2 and P < 3 mg m-2). In addition, applying a 2-cm layer of biochar between the sediment and soil reduced P and N leaching by 50%. According to the results, applying a 75-cm thick layer of sediments on agricultural sandy loam soils surrounding the lake seems a promising practice for improving plant yield and soil nutrient status without increasing of P and N leaching from soil.


Assuntos
Agricultura , Lagos , Fertilizantes/análise , Nitrogênio/análise , Nutrientes , Fósforo , Solo
10.
Mar Pollut Bull ; 160: 111652, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33181932

RESUMO

Estuaries of Southeast Asia are increasingly impacted by land-cover changes and pollution. Here, our research objectives were to (1) determine the origins of nutrient loads along the Can Gio estuary (Vietnam) and (2) identify the processes that affect the nutrient pools during the monsoon. We constructed four 24-h time-series along the salinity gradient measuring nutrient concentrations and stable isotopes values. In the upper estuary, urban effluents from Ho Chi Minh City were the main input of nutrients, leading to dissolved oxygen saturation <20%. In the lower estuary, ammonium and nitrite concentration peaks were explained by mangrove export. No contribution from aquaculture was detected, as it represents <0.01% of the total river discharge. Along the salinity gradient, nutrient inputs were rapidly consumed, potentially by phytoplankton while nitrate dual-stable isotopes indicated that nitrification occurred. Thus, even in a large and productive estuary, urban wastewater can affect nutrient dynamics with potentially important ecological risks.


Assuntos
Estuários , Águas Residuárias , Monitoramento Ambiental , Nutrientes , Rios , Estações do Ano , Vietnã
11.
An Acad Bras Cienc ; 92(3): e20190201, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33175015

RESUMO

In the present study, we evaluated the effects of the hydrolysis of phytate of defatted rice bran (DRB) by a pretreatment with non-commercial phytase produced by Saccharomyces cerevisiae (DRB-PS) compared to the application of Natuphos® (commercial phytase produced by the BASF Company) (DRB-PN) in diets for grass carp, Ctenopharyngodon idella. Fish (57.55 ± 0.4 g) fed one of the experimental diets in triplicates for 35 days. Effects of the phytase used on blood parameters, intestinal proteases and hepatic glucose were not observed (p > 0.05). Similarly, no differences were found for serum phosphorus (P). However, were found higher levels of calcium (9 and 5.25%) in the control treatment in relation to DRB-PS and DRB-PN respectively, besides higher calcium-phosphorus ratio was found in this treatment. For the fish carcass composition was not statistically different (p > 0.05) except total lipids, which showed its highest content in fish fed on the DRB-PN diet (p < 0.05). The obtained results suggested that the use of the phytase, irrespective to its source may eliminate the use of traditional P sources in fish diets.


Assuntos
6-Fitase , Carpas , Oryza , Ração Animal/análise , Animais , Dieta/veterinária , Nutrientes , Fósforo
12.
An Acad Bras Cienc ; 92(3): e20200764, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33175017

RESUMO

To determine the chemical composition and digestibility of insect meal for poultry made from the larvae of Tenebrio molitor (TL) and nymphs of Gryllus assimilis (GAN) a total excreta collection test was carried out, substituting 20% of the reference diet with each type of meal. The meals presented 6074 and 5975 kcal/Kg of gross energy, with 49.34% and 52.66% protein for TL and GAN respectively. The most nutrient digestibility was less than 65%, except for energy and ether-extract digestibility in the meal from Tenebrio molitor larvae, which were over 70%. The meals under analysis can be used as a source of nutrients in poultry diets.


Assuntos
Ração Animal , Galinhas , Ração Animal/análise , Fenômenos Fisiológicos da Nutrição Animal , Animais , Dieta/veterinária , Digestão , Insetos , Nutrientes
13.
Nat Commun ; 11(1): 5364, 2020 10 23.
Artigo em Inglês | MEDLINE | ID: mdl-33097697

RESUMO

Over the last ten years, satellite and geographically constrained in situ observations largely focused on the northern hemisphere have suggested that annual phytoplankton biomass cycles cannot be fully understood from environmental properties controlling phytoplankton division rates (e.g., nutrients and light), as they omit the role of ecological and environmental loss processes (e.g., grazing, viruses, sinking). Here, we use multi-year observations from a very large array of robotic drifting floats in the Southern Ocean to determine key factors governing phytoplankton biomass dynamics over the annual cycle. Our analysis reveals seasonal phytoplankton accumulation ('blooming') events occurring during periods of declining modeled division rates, an observation that highlights the importance of loss processes in dictating the evolution of the seasonal cycle in biomass. In the open Southern Ocean, the spring bloom magnitude is found to be greatest in areas with high dissolved iron concentrations, consistent with iron being a well-established primary limiting nutrient in this region. Under ice observations show that biomass starts increasing in early winter, well before sea ice begins to retreat. The average theoretical sensitivity of the Southern Ocean to potential changes in seasonal nutrient and light availability suggests that a 10% change in phytoplankton division rate may be associated with a 50% reduction in mean bloom magnitude and annual primary productivity, assuming simple changes in the seasonal magnitude of phytoplankton division rates. Overall, our results highlight the importance of quantifying and accounting for both division and loss processes when modeling future changes in phytoplankton biomass cycles.


Assuntos
Biomassa , Fitoplâncton/crescimento & desenvolvimento , Estações do Ano , Água do Mar/microbiologia , Biodiversidade , Carbono/análise , Clorofila/análise , Clima , Ecologia , Camada de Gelo , Luz , Biologia Marinha , Meteorologia , Nutrientes , Oceanos e Mares , Dinâmica Populacional , Microbiologia da Água
14.
PLoS One ; 15(10): e0239673, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33027289

RESUMO

This study used high throughput, image-based phenotyping (HTP) to distinguish growth patterns, detect facilitation and interpret variations to nutrient uptake in a model mixed-pasture system in response to factorial low and high nitrogen (N) and phosphorus (P) application. HTP has not previously been used to examine pasture species in mixture. We used red-green-blue (RGB) imaging to obtain smoothed projected shoot area (sPSA) to predict absolute growth (AG) up to 70 days after planting (sPSA, DAP 70), to identify variation in relative growth rates (RGR, DAP 35-70) and detect overyielding (an increase in yield in mixture compared with monoculture, indicating facilitation) in a grass-legume model pasture. Finally, using principal components analysis we interpreted between species changes to HTP-derived temporal growth dynamics and nutrient uptake in mixtures and monocultures. Overyielding was detected in all treatments and was driven by both grass and legume. Our data supported expectations of more rapid grass growth and augmented nutrient uptake in the presence of a legume. Legumes grew more slowly in mixture and where growth became more reliant on soil P. Relative growth rate in grass was strongly associated with shoot N concentration, whereas legume RGR was not strongly associated with shoot nutrients. High throughput, image-based phenotyping was a useful tool to quantify growth trait variation between contrasting species and to this end is highly useful in understanding nutrient-yield relationships in mixed pasture cultivations.


Assuntos
Fabaceae/crescimento & desenvolvimento , Nutrientes/metabolismo , Poaceae/crescimento & desenvolvimento , Agricultura/métodos , Variação Biológica da População/genética , Variação Biológica da População/fisiologia , Biomassa , Fabaceae/genética , Pradaria , Ensaios de Triagem em Larga Escala/métodos , Nitrogênio/metabolismo , Fósforo/metabolismo , Poaceae/genética , Solo
15.
Environ Monit Assess ; 192(11): 730, 2020 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-33111156

RESUMO

To manage agricultural landscapes more sustainably, we must understand and quantify the synergies and trade-offs between environmental impact, production, and other ecosystem services. Models play an important role in this type of analysis as generally it is infeasible to test multiple scenarios by experiment. These models can be linked with algorithms that optimise for multiple objectives by searching a space of allowable management interventions (the control variables). Optimisation of landscapes for multiple objectives can be computationally challenging, however, particularly if the scale of management is typically smaller (e.g. field scale) than the scale at which the objective is quantified (landscape scale) resulting in a large number of control variables whose impacts do not necessarily scale linearly. In this paper, we explore some practical solutions to this problem through a case study. In our case study, we link a relatively detailed, agricultural landscape model with a multiple-objective optimisation algorithm to determine solutions that both maximise profitability and minimise greenhouse gas emissions in response to management. The optimisation algorithm combines a non-dominated sorting routine with differential evolution, whereby a 'population' of 100 solutions evolves over time to a Pareto optimal front. We show the advantages of using a hierarchical approach to the optimisation, whereby it is applied to finer-scale units first (i.e. fields), and then the solutions from each optimisation are combined in a second step to produce landscape-scale outcomes. We show that if there is no interaction between units, then the solution derived using such an approach will be the same as the one obtained if the landscape is optimised in one step. However, if there is spatial interaction, or if there are constraints on the allowable sets of solutions, then outcomes can be quite different. In these cases, other approaches to increase the efficiency of the optimisation may be more appropriate-such as initialising the control variables for half of the population of solutions with values expected to be near optimal. Our analysis shows the importance of aligning a policy or management recommendation with the appropriate scale.


Assuntos
Ecossistema , Monitoramento Ambiental , Agricultura , Meio Ambiente , Nutrientes
16.
Mar Environ Res ; 162: 105179, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33065520

RESUMO

Nutrient enrichment can alter negatively benthic communities and reduce their ecological services. This study explores in two contrasting seasons (winter and summer), the effects of in situ nutrient enrichment at the community level on carbon metabolism and dissolved organic carbon (DOC) fluxes in two benthic communities dominated by the seagrass Cymodocea nodosa and by the macroalga Caulerpa prolifera. Under nutrient enrichment, C. nodosa increased total community biomass and diversity in summer, while net community production shifted from net autotrophic to net heterotrophic in winter. In contrast, C. prolifera became heterotrophic in summer, while no significant effects were found in winter. Regarding DOC fluxes, nutrient enrichment shifted C. nodosa from net DOC consumer in winter to a strong net DOC producer in summer, while C. prolifera seemed unaffected. Therefore, nutrient enrichment can promote conditional effects (positive, negative or neutral) in coastal areas depending both on macrophyte assemblages and season.


Assuntos
Carbono , Ecossistema , Ciclo do Carbono , Nutrientes , Estações do Ano
17.
Nat Commun ; 11(1): 5262, 2020 10 16.
Artigo em Inglês | MEDLINE | ID: mdl-33067453

RESUMO

Lifestyle, mainly dietary, interventions are first-line treatment for women with polycystic ovary syndrome (PCOS), but the optimal diet remains undefined. We combined a hyperandrogenized PCOS mouse model with a systematic macronutrient approach, to elucidate the impact of dietary macronutrients on the development of PCOS. We identify that an optimum dietary macronutrient balance of a low protein, medium carbohydrate and fat diet can ameliorate key PCOS reproductive traits. However, PCOS mice display a hindered ability for their metabolic system to respond to diet variations, and varying macronutrient balance did not have a beneficial effect on the development of metabolic PCOS traits. We reveal that PCOS traits in a hyperandrogenic PCOS mouse model are ameliorated selectively by diet, with reproductive traits displaying greater sensitivity than metabolic traits to dietary macronutrient balance. Hence, providing evidence to support the development of evidence-based dietary interventions as a promising strategy for the treatment of PCOS, especially reproductive traits.


Assuntos
Nutrientes/metabolismo , Síndrome do Ovário Policístico/metabolismo , Animais , Dieta , Dieta com Restrição de Proteínas , Feminino , Humanos , Estilo de Vida , Camundongos , Camundongos Endogâmicos C57BL , Nutrientes/análise , Síndrome do Ovário Policístico/dietoterapia
18.
J Environ Qual ; 49(1): 61-73, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33016353

RESUMO

Land reclamation in the Athabasca oil sands region requires construction of entire soil profiles from materials salvaged during mining. Although much attention has been paid to the limited supply of suitable topsoil materials and their impact on ecosystem recovery, suitable clean subsoil materials are also in limited supply, and their efficient and effective use is an important consideration for land managers in the region. Using data from an oil sands reclamation site in northern Alberta, Canada, we compared soil and foliar nutrients to a wildfire-impacted reference ecosystem with a similarity index. Specifically, we evaluated the similarity of forest floor-mineral mix (FFM) and peat-mineral mix (PM) as topsoil, as well as the effect of different depths of salvaged B and C horizon subsoil with PM on top. All reclamation treatments were planted with jack pine (Pinus banksiana Lamb.) and trembling aspen (Populus tremuloides Michx.), which were used to examine foliar nutrient concentrations. Individual macronutrient concentrations were different among treatments in total soil nutrients, but differences decreased in soil bioavailable nutrients and disappeared altogether in foliar nutrients. The similarity index revealed that distinct differences existed between treatments, with FFM being the most similar to the wildfire site. It also revealed a potential deficiency in foliar and soil bioavailable Mn on PM, and that increased water content of deeper subsoils had little to no effect. With use of this nutrient profile similarity index, reclamation practitioners may be able to determine if different soil prescriptions lead to higher levels of similarity to natural ecosystems more quickly.


Assuntos
Ecossistema , Campos de Petróleo e Gás , Alberta , Animais , Nutrientes , Ovinos , Solo
19.
J Environ Qual ; 49(1): 140-151, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33016365

RESUMO

Watershed managers generally focus on P reduction strategies to combat freshwater eutrophication despite evidence that N co-limits primary production. Our objective was to test the role of P in limiting stream periphyton biomass within the Buffalo River watershed in Arkansas by conducting a 31-d streamside mesocosm experiment. To represent potentially different starting states, cobbles were transplanted from two different tributary streams and initially exposed to a range of P (0, 0.012, 0.025, 0.05, 0.1, and 0.2 mg L-1 P) to assess benthic ash-free dry mass (AFDM) and chlorophyll-a (chl a) and responses during a P only enrichment period. Later, the experiment was continued under a N/P (10:1 molar ratio) enrichment gradient to examine co-limitation. Mean AFDM was higher on Day 31 of the N+P enrichment compared with Day 17 of the P-only enrichment (p < .001). Overall differences in AFDM and chl a were observed between cobbles from different stream sites. Phosphorus enrichment stimulated benthic chl a biomass, but enrichment effects were greater when streams were enriched with N+P (p < .001). Chlorophyll-a increased (4.4-57.9 mg m-2 ) with increasing P concentrations (p < .001) after P enrichment but was threefold greater after N+P enrichment, increasing from 13.3 to 171.1 mg m-2 across the enrichment gradient. Results support the need to consider both N and P limitation in freshwater systems and demonstrate that potential increases in nutrient concentrations may influence accumulation of algae on cobble substrates from the Buffalo River watershed.


Assuntos
Nitrogênio/análise , Fósforo/análise , Arkansas , Biomassa , Nutrientes
20.
J Environ Qual ; 49(3): 517-533, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-33016389

RESUMO

Nutrient pollution is considered a wicked problem because of its many significant economic, social, and environmental impacts that are caused by multiple pollutants originating from a variety of sources and pathways that exist across different temporal and spatial scales. Further adding to the difficulty in managing nutrient pollution is that it is a global, rural, and urban problem. A systems approach can improve nutrient management by incorporating technological, environmental, and societal considerations. This approach can consider valuation of monetized and nonmonetized co-benefits and the inherent consequences that make up a nutrient management program. In this introduction to a special collection of papers on nutrient pollution, we describe several systems frameworks that can be used to support nutrient management and evaluation of system performance as it relates to impacts, then highlight several attributes and barriers of nutrient management that point to the need for a systems framework, and conclude with thoughts on implementing systems approaches to nutrient management with effective community engagement and use of new technologies. This special collection presents results from a USEPA Science to Achieve Results (STAR) initiative to advance solutions to nutrient pollution through innovative and sustainable research and demonstration projects for nutrient management based on a systems approach. These studies evaluate several promising nutrient control technologies for stormwater or domestic wastewater, investigate the effects of agricultural conservation practices and stream restoration strategies on nutrient loads, and discuss several challenges and opportunities-social, policy, institutional, and financial considerations-that can accelerate adoption of reliable technologies to achieve system-level outcomes.


Assuntos
Nutrientes , Rios , Agricultura , Análise de Sistemas , Águas Residuárias
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