Journal articles on the topic 'Nutrient dynamic'
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Niu, Lixia, Pieter van Gelder, Xiangxin Luo, Huayang Cai, Tao Zhang, and Qingshu Yang. "Implications of Nutrient Enrichment and Related Environmental Impacts in the Pearl River Estuary, China: Characterizing the Seasonal Influence of Riverine Input." Water 12, no. 11 (November 19, 2020): 3245. http://dx.doi.org/10.3390/w12113245.
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The Pearl River estuary is an ecologically dynamic region located in southern China that experiences strong gradients in its biogeochemical properties. This study examined the seasonality of nutrient dynamics, identified related environmental responses, and evaluated how river discharge regulated nutrient sink and source. The field investigation showed significant differences of dissolved nutrients with seasons and three zones of the estuary regarding the estuarine characteristics. Spatially, nutrients exhibited a clear decreasing trend along the salinity gradient; temporally, their levels were obviously higher in summer than other seasons. The aquatic environment was overall eutrophic, as a result of increased fluxes of nitrogen and silicate. This estuary was thus highly sensitive to nutrient enrichment and related pollution of eutrophication. River discharge, oceanic current, and atmospheric deposition distinctly influenced the nutrient status. These factors accordingly may influence phytoplankton that are of importance in coastal ecosystems. Phytoplankton (in terms of chlorophyll) was potentially phosphate limited, which then more frequently resulted in nutrient pollution and blooms. Additionally, the nutrient sources were implied according to the cause–effect chains between nutrients, hydrology, and chlorophyll, identified by the PCA-generated quantification. Nitrogen was constrained by marine-riverine waters and their mutual increase-decline trend, and a new source was supplemented along the transport from river to sea, while a different source of terrestrial emission from coastal cities contributed to phosphate greatly.
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Kalra, Tarandeep S., Neil K. Ganju, and Jeremy M. Testa. "Development of a submerged aquatic vegetation growth model in the Coupled Ocean–Atmosphere–Wave–Sediment Transport (COAWST v3.4) model." Geoscientific Model Development 13, no. 11 (November 2, 2020): 5211–28. http://dx.doi.org/10.5194/gmd-13-5211-2020.
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Abstract. The coupled biophysical interactions between submerged aquatic vegetation (SAV), hydrodynamics (currents and waves), sediment dynamics, and nutrient cycling have long been of interest in estuarine environments. Recent observational studies have addressed feedbacks between SAV meadows and their role in modifying current velocity, sedimentation, and nutrient cycling. To represent these dynamic processes in a numerical model, the presence of SAV and its effect on hydrodynamics (currents and waves) and sediment dynamics was incorporated into the open-source Coupled Ocean–Atmosphere–Wave–Sediment Transport (COAWST) model. In this study, we extend the COAWST modeling framework to account for dynamic changes of SAV and associated epiphyte biomass. Modeled SAV biomass is represented as a function of temperature, light, and nutrient availability. The modeled SAV community exchanges nutrients, detritus, dissolved inorganic carbon, and dissolved oxygen with the water-column biogeochemistry model. The dynamic simulation of SAV biomass allows the plants to both respond to and cause changes in the water column and sediment bed properties, hydrodynamics, and sediment transport (i.e., a two-way feedback). We demonstrate the behavior of these modeled processes through application to an idealized domain and then apply the model to a eutrophic harbor where SAV dieback is a result of anthropogenic nitrate loading and eutrophication. These cases demonstrate an advance in the deterministic modeling of coupled biophysical processes and will further our understanding of future ecosystem change.
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Bonachela, J. A., S. D. Allison, A. C. Martiny, and S. A. Levin. "A model for variable phytoplankton stoichiometry based on cell protein regulation." Biogeosciences 10, no. 6 (June 27, 2013): 4341–56. http://dx.doi.org/10.5194/bg-10-4341-2013.
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Abstract. The elemental ratios of marine phytoplankton emerge from complex interactions between the biotic and abiotic components of the ocean, and reflect the plastic response of individuals to changes in their environment. The stoichiometry of phytoplankton is, thus, dynamic and dependent on the physiological state of the cell. We present a theoretical model for the dynamics of the carbon, nitrogen and phosphorus contents of a phytoplankton population. By representing the regulatory processes controlling nutrient uptake, and focusing on the relation between nutrient content and protein synthesis, our model qualitatively replicates existing experimental observations for nutrient content and ratios. The population described by our model takes up nutrients in proportions that match the input ratios for a broad range of growth conditions. In addition, there are two zones of single-nutrient limitation separated by a wide zone of co-limitation. Within the co-limitation zone, a single point can be identified where nutrients are supplied in an optimal ratio. When different species compete, the existence of a wide co-limitation zone implies a more complex pattern of coexistence and exclusion compared to previous model predictions. However, additional comprehensive laboratory experiments are needed to test our predictions. Our model contributes to the understanding of the global cycles of oceanic nitrogen and phosphorus, as well as the elemental ratios of these nutrients in phytoplankton populations.
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Bonachela, J. A., S. D. Allison, A. C. Martiny, and S. A. Levin. "A model for variable phytoplankton stoichiometry based on cell protein regulation." Biogeosciences Discussions 10, no. 2 (February 21, 2013): 3241–79. http://dx.doi.org/10.5194/bgd-10-3241-2013.
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Abstract. The elemental ratios of marine phytoplankton emerge from complex interactions between the biotic and abiotic components of the ocean, and reflect the plastic response of individuals to changes in their environment. The stoichiometry of phytoplankton is, thus, dynamic and dependent on the physiological state of the cell. We present a theoretical model for the dynamics of the carbon, nitrogen and phosphorus contents of a phytoplankton population. By representing the regulatory processes controlling nutrient uptake, and focusing on the relation between nutrient content and protein synthesis, our model qualitatively replicates existing experimental observations for nutrient content and ratios. The population described by our model takes up nutrients in proportions that match the input ratios for a broad range of growth conditions. In addition, there are two zones of single-nutrient limitation separated by a wide zone of co-limitation. Within the co-limitation zone, a single point can be identified where nutrients are supplied in an optimal ratio. The existence of a wide co-limitation zone affects the standard picture for species competing for nitrogen and phosphorus, which shows here a much richer pattern. However, additional comprehensive laboratory experiments are needed to test our predictions. Our model contributes to the understanding of the global cycles of oceanic nitrogen and phosphorus, as well as the elemental ratios of these nutrients in phytoplankton populations.
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Torres-Duque, Fabiola, Armando Gómez-Guerrero, Libia I. Trejo-Téllez, Valentín J. Reyes-Hernández, and Arian Correa-Díaz. "Stoichiometry of needle litterfall of Pinus hartwegii Lindl. in two alpine forests of central Mexico." Revista Chapingo Serie Ciencias Forestales y del Ambiente 28, no. 1 (December 2021): 57–74. http://dx.doi.org/10.5154/r.rchscfa.2020.12.077.
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Introduction: It is essential to have baselines on nutrient dynamics in forests, due to disturbances that climate change may cause.Objective: To quantify the annual production of needles of Pinus hartwegii Lindl. and the proportion of nutrients in the alpine forests of Jocotitlán (JO) and Tláloc (TL) mountains, Estado de México.Materials and methods: A total of 12 circular needle litter traps (30 cm diameter) were placed at ground level, in each forest, distributed in four topographically contrasting sites. For one year, 228 leaf mass measurements and 1 140 chemical determinations were made to determine needle stoichiometry. Measurements were subjected to a longitudinal analysis of variance, by testing trends over time (P < 0.05).Results and discussion: Needle production in JO were 67 % higher (11.2 Mg∙ha-1∙year-1) than in TL (6.7 Mg∙ha-1∙year-1); needle litterfall was higher during summer (June and July, months with higher precipitation). For JO, nutrient flux was 98.0, 5.2, 8.7, 24.6, and 5.6 kg∙ha-1∙year-1 for N, P, K, Ca, and Mg, respectively; for TL it was 55.3, 3.4, 7.8, 14.4, and 4.7 kg∙ha-1∙year-1 in the same order of nutrients. Nutrient concentrations were lower from March to May. Except for K, nutrient concentrations and needle production showed quadratic and cubic seasonal trends. Mg dynamics and N:Mg and N:K ratios in TL were more positive for tree growth.Conclusions: Jocotitlán and Tláloc forests produce significant needle mass (compared to other ecosystems) with high dynamic in nutrient transfers.
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Liu, Xingyue, Ziyuan Wang, Xi Liu, Zhiyun Lu, Dawen Li, and Hede Gong. "Dynamic Change Characteristics of Litter and Nutrient Return in Subtropical Evergreen Broad-Leaved Forest in Different Extreme Weather Disturbance Years in Ailao Mountain, Yunnan Province." Forests 13, no. 10 (October 10, 2022): 1660. http://dx.doi.org/10.3390/f13101660.
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By studying the dynamic change characteristics of litter production, composition, nutrient content, and return amount of different components in different extreme weather interference years of Ailao Mountain evergreen broad-leaved forest, the paper provides theoretical support for the post-disaster nutrient cycle, ecological recovery, and sustainable development of the subtropical mid-mountain humid evergreen broad-leaved forest. Square litter collectors were randomly set up to collect litter. After drying to a constant mass, we calculated the seasonal and annual litter volume and the contents of organic carbon (C), total nitrogen (N), total phosphorus (P), total potassium (k), total sulfur (S), total calcium (Ca), and total magnesium (Mg). Finally, the nutrient return amount is comprehensively calculated according to the litter amount and element content. We tracked dynamic changes in litter quantity, nutrient composition, and nutrient components across different years. The results showed that the amount of litter from 2005 to 2015 was 7704–8818 kg·hm−2, and the order of magnitude was: 2005 (normal year) > 2015 (extreme snow and ice weather interference) > 2010 (extreme drought weather interference); the composition mainly included branches, leaves, fruit (flowers), and other components (bark, moss, lichen, etc.), of which the proportion of leaves was the largest, accounting for 41.70%–61.52%; The monthly changes and total amounts in different years exhibited single or double peak changes, and the monthly litter components in different years showed significant seasonality. In this study, the nutrient content of litter was higher than that of litter branches each year. The total amount of litter and the nutrient concentration of each component are C, Ca, N, K, Mg, S, and P, from large to small. The order of nutrient return in different years was the same as that of litter, and the returns of nutrients in litter leaves were greater than that of litter branches. The ratio of nutrient returns of litter and litter branches from 2005 to 2010 was 2.03, 1.23, and 3.69, respectively. The research shows that the litter decreased correspondingly under the extreme weather disturbance, and the impact of the extreme dry weather disturbance was greater than that of the extreme ice and snow weather disturbance. However, the evergreen broad-leaved forest in the study area recovers well after being disturbed. The annual litter amount and nutrient return amount is similar to that of evergreen broad-leaved forests in the same latitude and normal years in other subtropical regions. The decomposition rate and seasonal dynamics of litter nutrients are not greatly affected by extreme weather.
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Raghavan, Varsha, and Eduardo A. Groisman. "Species-Specific Dynamic Responses of Gut Bacteria to a Mammalian Glycan." Journal of Bacteriology 197, no. 9 (February 17, 2015): 1538–48. http://dx.doi.org/10.1128/jb.00010-15.
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ABSTRACTThe mammalian intestine provides nutrients to hundreds of bacterial species. Closely related species often harbor homologous nutrient utilization genes and cocolonize the gut, raising questions regarding the strategies mediating their stable coexistence. Here we reveal that relatedBacteroidesspecies that can utilize the mammalian glycan chondroitin sulfate (CS) have diverged in the manner in which they temporally regulate orthologous CS utilization genes. Whereas certainBacteroidesspecies display a transient surge in CS utilization transcripts upon exposure to CS, other species exhibit sustained activation of these genes. Remarkably, species-specific expression dynamics are retained even when the key players governing a particular response are replaced by those from a species with a dissimilar response.Bacteroidesspecies exhibiting distinct expression behaviors in the presence of CS can be cocultured on CS. However, they vary in their responses to CS availability and to the composition of the bacterial community when CS is the sole carbon source. Our results indicate that diversity resulting from regulation of polysaccharide utilization genes may enable the coexistence of gut bacterial species using a given nutrient.IMPORTANCEGenes mediating a specific task are typically conserved in related microbes. For instance, gutBacteroidesspecies harbor orthologous nutrient breakdown genes and may face competition from one another for these nutrients. How, then, does the gut microbial composition maintain such remarkable stability over long durations? We establish that in the case of genes conferring the ability to utilize the nutrient chondroitin sulfate (CS), microbial species vary in how they temporally regulate these genes and exhibit subtle growth differences on the basis of CS availability and community composition. Similarly to how differential regulation of orthologous genes enables related species to access new environments, gut bacteria may regulate the same genes in distinct fashions to reduce the overlap with coexisting species for utilization of available nutrients.
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Coggan, Nicole, Fiona J. Clissold, and Stephen J. Simpson. "Locusts use dynamic thermoregulatory behaviour to optimize nutritional outcomes." Proceedings of the Royal Society B: Biological Sciences 278, no. 1719 (February 2, 2011): 2745–52. http://dx.doi.org/10.1098/rspb.2010.2675.
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Because key nutritional processes differ in their thermal optima, ectotherms may use temperature selection to optimize performance in changing nutritional environments. Such behaviour would be especially advantageous to small terrestrial animals, which have low thermal inertia and often have access to a wide range of environmental temperatures over small distances. Using the locust, Locusta migratoria , we have demonstrated a direct link between nutritional state and thermoregulatory behaviour. When faced with chronic restrictions to the supply of nutrients, locusts selected increasingly lower temperatures within a gradient, thereby maximizing nutrient use efficiency at the cost of slower growth. Over the shorter term, when locusts were unable to find a meal in the normal course of ad libitum feeding, they immediately adjusted their thermoregulatory behaviour, selecting a lower temperature at which assimilation efficiency was maximal. Thus, locusts use fine scale patterns of movement and temperature selection to adjust for reduced nutrient supply and thereby ameliorate associated life-history consequences.
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Ge, Xiaogai, Benzhi Zhou, and Yilin Tang. "Litter Production and Nutrient Dynamic on a Moso Bamboo Plantation following an Extreme Disturbance of 2008 Ice Storm." Advances in Meteorology 2014 (2014): 1–10. http://dx.doi.org/10.1155/2014/750865.
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Ice storm is known to play a role in determining forest succession and litter dynamics constitute an important aspect of nutrient cycling in forest ecosystems. However, ice storm effects on amount and pattern of litterfall are not clearly understood. We investigated litter production and litter leaf nutrient dynamic in a moso bamboo plantation in China following an extreme disturbance of ice storm in 2008. The litterfall in on-years was significantly lower than in off-years. Ice storm caused total litterfall increasing from 16.68% to 35.60% and greatly disturbed the litterfall peak rhythm especially in the on-year. The litter leaf nutrient concentrations at two latitudes significantly fluctuated after ice-snow disaster in 2008, litter leaf stoichiometric traits indicated that litter leaf chemistry showed more easily decomposition with higher C/P ratio, N/P ratio, and lower C/N ratio. It is clear from this study that litterfall restoration dynamic would result in long-term changes in litter nutrient cycling and may help predicting below ground carbon dynamic in future research as well as subtropical forest inventories following extreme disturbance.
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Brønd, Søren, and Jan Scherfig. "DYNAMIC TEMPERATURE CHANGES IN NUTRIENT REMOVAL PLANTS." Water Science and Technology 30, no. 2 (July 1, 1994): 205–8. http://dx.doi.org/10.2166/wst.1994.0044.
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Nitrification and denitrification processes are very sensitive to temperature changes below 10 °C. Because of severe eutrophication problems in e.g. Northern Europe Nitrogen removal must be kept throughout the winter. To aid in the design and optimization of treatment plants a dynamic temperature model has been developed. The major findings is that the temperature variation is very dependent on local wind conditions. The model can be used in the design process to minimize factors causing temperature drops during cold weather periods.
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Bonachela, J. A., M. Raghib, and S. A. Levin. "Dynamic model of flexible phytoplankton nutrient uptake." Proceedings of the National Academy of Sciences 108, no. 51 (December 5, 2011): 20633–38. http://dx.doi.org/10.1073/pnas.1118012108.
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Litchman, Elena, Christopher A. Klausmeier, and Peter Bossard. "Phytoplankton nutrient competition under dynamic light regimes." Limnology and Oceanography 49, no. 4part2 (January 31, 2004): 1457–62. http://dx.doi.org/10.4319/lo.2004.49.4_part_2.1457.
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Aji, Galih Kusuma, Kenji Hatou, and Tetsuo Morimoto. "Performance of Long Short-Term Memory Networks for Modeling the Response of Plant Growth to Nutrient Solution Temperature in Hydroponic." Agroindustrial Journal 7, no. 1 (October 5, 2020): 452. http://dx.doi.org/10.22146/aij.v7i1.60391.
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This study examines the development of an approach for modeling the response of plant growth to nutrient solution temperature in hydroponic cultivation in a dynamic system. Nutrient solution temperature is one of the essential manipulating factors for plant growth in hydroponic cultivation. Determining the optimal control strategy of nutrient solution temperature during cultivation could lead to maximize the growth of the plant. By identifying the process using a dynamic system, the optimal control strategy can be determined. However, developing a dynamic model of plant growth to nutrient solution temperature is not easy due to physiological behavior between them are quite complex and uncertain. We propose the long short-term memory (LSTM) networks to identify and develop a model of dynamic characteristics of plant growth as affected by the nutrient solution temperature. Chili pepper plants were used to obtain time-series data of plant growth, with five different types of dynamic nutrient solution temperature patterns for system identification. The results showed that the proposed LSTM model provides promising performance in predicting the response of plant growth to nutrient solution temperature in hydroponic cultivation.
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Ramírez-Puebla, Shamayim T., Luis E. Servín-Garcidueñas, Berenice Jiménez-Marín, Luis M. Bolaños, Mónica Rosenblueth, Julio Martínez, Marco Antonio Rogel, Ernesto Ormeño-Orrillo, and Esperanza Martínez-Romero. "Gut and Root Microbiota Commonalities." Applied and Environmental Microbiology 79, no. 1 (October 26, 2012): 2–9. http://dx.doi.org/10.1128/aem.02553-12.
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ABSTRACTAnimal guts and plant roots have absorption roles for nutrient uptake and converge in harboring large, complex, and dynamic groups of microbes that participate in degradation or modification of nutrients and other substances. Gut and root bacteria regulate host gene expression, provide metabolic capabilities, essential nutrients, and protection against pathogens, and seem to share evolutionary trends.
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Ngan, Nguyen Vo Chau, Huynh Van Thao, and Nguyen Dinh Giang Nam. "Nutrient dynamics in water and soil under conventional rice cultivation in the Vietnamese Mekong Delta." F1000Research 10 (January 5, 2023): 1145. http://dx.doi.org/10.12688/f1000research.73904.2.
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Background The evaluation of nutrient variability plays a crucial role in accessing soil potentials and practical intervention responses in rice production systems. Synthetic fertilizer applications and cultivation practices are considered key factors affecting nutrient dynamics and availability. Here, we assessed the nutrient dynamics in surface, subsurface water and soil under local water management and conventional rice cultivation practices in the Vietnamese Mekong Delta. Methods We implemented a field experiment (200 m 2) in the 2018 wet season and the 2019 dry season in a triple rice-cropping field. Surface water, subsurface water (30–45 cm), and topsoil (0–20 cm) were collected eight samples during the rice-growing seasons to clarify its nutrient dynamic. Results The results showed that N-NH 4 +, P-PO 4 3- and total P peaks were achieved after fertilizing. Irrespective of seasons, the nutrient content in surface water was always greater than that of subsurface water ( P<0.001), with the exception of N-NO 3 -, no significant difference was disclosed ( P>0.05). When comparing the wet and dry seasons, nutrient concentrations exhibited minor differences ( P>0.05). Under conventional rice cultivation, the effects of synthetic fertilizer topdressing on the total N, soil organic matter (SOM), and total P were negligible in the soil. Higher rates of N fertilizer application did not significantly increase soil N-NH 4 +, total N, yet larger P fertilizer amounts substantially enhanced soil total P ( P<0.001). Conclusions Under conventional rice cultivation, the low concentration of N-NH 4 +, P-PO 4 3- and total P in the subsurface water indicated that nutrient losses mainly occur through runoff rather than leaching. Notably, nutrient content in soil was fairly high, whilst SOM was varied from low to medium between seasons. Future work should consider the nutrient balance and nutrient dynamic simulation on surface and subsurface.
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Lee, Yit Leng, Osumanu Haruna Ahmed, Samsuri Abdul Wahid, Mohamadu Boyie Jalloh, and Adiza Alhassan Muzah. "Nutrient Release and Ammonia Volatilization from Biochar-Blended Fertilizer with and without Densification." Agronomy 11, no. 10 (October 18, 2021): 2082. http://dx.doi.org/10.3390/agronomy11102082.
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Blending fertilizer with biochar followed by densification to make it into a tablet can enhance the adsorption of fertilizer on the biochar surface and reduce the nutrient loss during handling. However, the nutrient release and ammonia volatilization from biochar-blended fertilizer with and without densification are not well understood. The objectives of this study were to determine the nutrient release and ammonia volatilization from an acid soil applied with biochar-blended NPK fertilizer with and without densification. The nutrient release of biochar-blended NPK was determined using water incubation for 30 days, whereas daily loss of ammonia was measured using a closed dynamic air flow system for 10 days. The densified biochar-blended NPK caused stronger physical binding of the nutrients within the tablet in addition to stronger chemical bondings between the nutrients with the biochar’s functional groups. As a result, nutrient release in the water incubation from the biochar-blended NPK fertilizer tablet was slower. However, blending the biochar with the NPK fertilizer increased soil ammonia volatilization relative to the NPK fertilizer alone. This demonstrates that the biochar-blended fertilizer tablet has the potential to serve as a slow release fertilizer for crop cultivation.
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KUMAR, Isaiah Nirmal, Poliyaparambil Ravi SAJISH, Rita Nirmal KUMAR, George BASIL, and Viyol SHAILENDRA. "Nutrient Dynamics in an Avicennia marina (Forsk.) Vierh., Mangrove Forest in Vamleshwar, Gujarat, India." Notulae Scientia Biologicae 3, no. 1 (March 7, 2011): 51–56. http://dx.doi.org/10.15835/nsb315594.
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The study was carried out to determine the nutrient budget of plants, sediments and nutrient dynamics in an Avicennia marina (Forsk.) Vierh., dominated forest in Vamleshwar near Narmada estuary, West Coast of Gujarat for a period of one year from November 2008 to October 2009. The average tree height of the mangrove is 1.5 to 2 m without much vertical stratification. Allometric methodology was used to measure the biomass, and yield a figure of 86.47 t ha-1 and the litter fall rate amounted to 2.9 t ha-1. Nutrient stocks of N, P and K in this mangrove were 137.05, 14.38 and 241.29 kg ha-1, with an annual accumulation of 55.74, 12.38 and 83.94 kg ha-1, and an annual return of 51.30, 10.83 and 13.52 kg ha-1, respectively, in the form of litter. The annual uptake for N, P and K were 61.04, 14.28 and 97.46 kg ha-1, and turnover rates of N, P and K were estimated at 3, 6 and 14 years, respectively, for the study period. Flow coefficients, which reveal the dynamic processes of nutrients between mangrove plants and sediments, are also explained. The present study concluded that the A. marina dominated mangrove plantation is more efficient in nutrient use and conservation.
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Kurniawan, Andi, and Tatsuya Yamamoto. "Accumulation of NH4+ and NO3− inside Biofilms of Natural Microbial Consortia: Implication on Nutrients Seasonal Dynamic in Aquatic Ecosystems." International Journal of Microbiology 2019 (June 2, 2019): 1–7. http://dx.doi.org/10.1155/2019/6473690.
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Microbial biofilms are ubiquitous in aquatic ecosystems. Inside the biofilm is the nutrient-rich microenvironment promoted by the accumulation of the nutrient ions such as NH4+ and NO3− from surrounding water. The present study investigated the characteristics of NH4+ and NO3− accumulation into the biofilm of natural microbial consortia collected from Lake Biwa, Japan. The results showed the following: (1) the concentrations of NH4+ and NO3− inside the biofilm were much higher than those in the surrounding water; (2) the nutrient ion concentration inside the biofilm changed in synchrony with those in the surrounding water; (3) biofilm polymers have both positively and negatively charged sites; (4) electrostatic attractive interactions between the charged sites on biofilm polymers and oppositely charged ions outside the biofilm seem to play important roles in the accumulation of nutrient ions into the biofilm from the surrounding water; (5) the bacterial community structure differs between the biofilm and surrounding water. The present study revealed that the accumulation of nutrient ions into the biofilm indicates the removal of these ions from water outside the biofilm. According to the result of this study, accumulation of ions such as NH4+ and NO3− into the biofilm of natural microbial consortia may have implications on nutrients seasonal dynamic in aquatic ecosystems.
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Carrero-Col�n, Militza, Cindy H. Nakatsu, and Allan Konopka. "Effect of Nutrient Periodicity on Microbial Community Dynamics." Applied and Environmental Microbiology 72, no. 5 (May 2006): 3175–83. http://dx.doi.org/10.1128/aem.72.5.3175-3183.2006.
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ABSTRACT When microbes are subjected to temporal changes in nutrient availability, growth rate and substrate affinity can contribute to competitive fitness and thereby affect microbial community structure. This hypothesis was tested using planktonic bacterial communities exposed to nutrient additions at 1-, 3-, 7-, or 14-day intervals. Growth rates after nutrient addition were inversely proportional to the pulse interval and declined from 0.5 h−1 to 0.15 h−1 as the pulse interval increased from 1 to 14 days. The dynamics of community structure were monitored by 16S rRNA gene PCR-denaturing gradient gel electrophoresis. At pulse intervals of more than 1 day, the community composition continued to change over 130 days. Although replicate systems exposed to the same pulse interval were physiologically similar, their community compositions could exhibit as much dissimilarity (Dice similarity coefficients of <0.5) as did systems operated at different intervals. Bacteria were cultivated from the systems to determine if the physiological characteristics of individual members were consistent with the measured performance of the systems. The isolates fell into three bacterial divisions, Bacteroidetes, Proteobacteria, and Actinobacteria. In agreement with community results, bacteria isolated from systems pulsed every day with nutrients had higher growth rates and ectoaminopeptidase specific activities than isolates from systems pulsed every 14 days. However, the latter isolates did not survive starvation longer than those provided with nutrients every day. The present study demonstrates the dynamic nature of microbial communities exposed to even simple and regular environmental discontinuities when a substantial pool of species that can catabolize the limiting substrate is present.
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Ribas-Ribas, M., E. Anfuso, A. Gómez-Parra, and J. M. Forja. "Tidal and seasonal carbon and nutrient dynamics of the Guadalquivir estuary and the Bay of Cádiz (SW Iberian Peninsula)." Biogeosciences 10, no. 7 (July 4, 2013): 4481–91. http://dx.doi.org/10.5194/bg-10-4481-2013.
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Abstract. To study the effects of the physical environment on carbon and nutrient cycle dynamics on the north-eastern shelf of the Gulf of Cádiz, changes in currents, tides, salinity, temperature, carbon system parameters (fugacity of CO2 (fCO2), dissolved organic carbon, dissolved inorganic carbon (DIC) and pH) and other related parameters(dissolved oxygen, total dissolved nitrogen (TDN), nutrients and suspended particulate matter) were measured in transects across the Guadalquivir estuary and Bay of Cádiz mouths. The main objective of this study is to investigate the influence of these inner ecosystems on the carbon and nutrient distributions on the adjacent continental shelf. Three cruises were undertaken in June 2006, November 2006 and February 2007. During the whole study period, Guadalquivir estuary exported components at a rate of 3 Gmol of SiO2, 4 Gmol of DIN, 3 Gmol of TDN, 31 Gmol of DOC and 604 Gmol of DIC per year. On the other hand, Bay of Cádiz imported 3 Gmol of SiO2, 1 Gmol of DIN, 2 Gmol of TDN, 33 Gmol of DOC and 562 Gmol of DIC per year. Diurnal variability of fCO2 could have a potentially important implication on the estimate of air–sea CO2 fluxes. Tides influence velocity and transport of carbon and nutrients: we found statistically significant differences (p < 0.0001, n = 220) between the flood tide (the mean velocity was 4.85 cm s–1) and the ebb tide (the mean velocity was −5.67 cm s–1). Biological activity and diurnal changes have also an important role on the carbon and nutrient dynamics. Seasonal carbon and nutrient variations were found. During June, both systems were exporting components to the adjacent continental shelf of the Gulf of Cádiz, whereas in February both systems were importing. Monthly studies should be undertaken to completely understand this dynamic system.
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Sharma, Amit, Anuj Kumar Sharma, and Kulbhushan Agnihotri. "The dynamic of plankton–nutrient interaction with delay." Applied Mathematics and Computation 231 (March 2014): 503–15. http://dx.doi.org/10.1016/j.amc.2014.01.042.
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Guo, Yue Feng, Yun Feng Yao, Fu Cang Qin, and Wei Qi. "Analysis of Soil Organic Matter and Soil Total Nitrogen Condition under Different Vegetation Patterns of Huanghuadianzi Small Watershed." Advanced Materials Research 807-809 (September 2013): 1839–42. http://dx.doi.org/10.4028/www.scientific.net/amr.807-809.1839.
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Different vegetation patterns have difference influenced on the soil nutrients and the soil nutrient contents of different soil layers in the same vegetation patterns are also different in size. In this paper, we analyze the main soil nutrients of different soil layers in different vegetation patterns in Huanghuadianzi small watershed in Ao HanQI of Chifeng in China. The result shows that in different vegetation patterns, the secondary forest of natural bush have an obvious effect on the nutrient and concentration of organic; in the artificial forest, mingled forest has a better improving effect on soil than the pure forest and natural grassland has the smallest effect; in the same vegetation patterns, organic, total nitrogen present an overall reduction trend with the deepening of soil layer accept 40-60cm soil layers. The analysis result of this paper can provide a theoretical basis for further researching the dynamic nutrient change, tree variety optimization arrangement and regional land use planning in forest grass zone.
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Gerrits, Walter J., Marijke A. Schop, and Sonja de Vries. "309 ASAS-EAAP Talk: Modelling digestion kinetics: the next step in the evaluation of feed ingredients." Journal of Animal Science 98, Supplement_4 (November 3, 2020): 45. http://dx.doi.org/10.1093/jas/skaa278.082.
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Abstract There is increasing importance of upcycling of low-opportunity-cost feed, food waste, and food processing byproducts into animal products, strongly increasing the variation in the nutritional quality of feed ingredients. Traditionally, feed ingredients are evaluated based on their measured extent of digestion. Increasing awareness that not only the total yield of nutrients, but also their absorption kinetics, affect their metabolic fate after absorption, and a growing body of evidence of complex interactions taking place inside the gastro-intestinal tract urges development of new approaches. In a recently developed approach (Schop, 2020), we propose a combination of in vitro methodology and dynamic modelling of the digestion process as an alternative to conventional feed ingredient evaluation, and made the first steps in the development of such a system. The digestion potential, evaluated in vitro, is considered as the true property of feed ingredients. Then, prediction of digesta transit, nutrient hydrolysis and absorption, following the intake of a complete feed, determines the extent to which the digestion potential of each ingredient is exploited. The dynamic, mechanistic model developed by Schop for growing pigs comprises 48 state variables representing dietary nutrients, hydrolysis products, endogenous components, and microbial biomass. Driving variables are ingested nutrients from feed ingredients, characterized in vitro (solubility, undegradable fraction, maximum rate of digestion). Passage of digesta is modelled as a function of nutrient solubility, diet viscosity and feed intake. The extent of protein digestion and extent and rate of starch digestion, but not absorption of amino acids, were adequately predicted by the model. Future efforts should focus on modelling digesta properties and transit, translation of in vitro digestion kinetic data and generating reliable in vivo data on nutrient absorption kinetics across feed ingredients. Schop, T.A. 2020 Modelling digestion kinetics in pigs. Predicting nutrient absorption based on diet and ingredient properties. PhD thesis, Wageningen University, Wageningen, NL.
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Rojas M., Jairo, Victor Caicedo, and Yeirme Jaimes. "Biomass decomposition dynamic in agroforestry systems with Theobroma cacao L. in Rionegro, Santander (Colombia)." Agronomía Colombiana 35, no. 2 (May 1, 2017): 182–89. http://dx.doi.org/10.15446/agron.colomb.v35n2.60981.
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The study was carried out in an agroforestry system (AFS) with cacao trees already established in La Suiza Research Center, Corpoica, located in Rionegro, Santander (Colombia). The objective was to evaluate biomass input and nutrient release rate of the species that comprise the AFS (Gmelina arbórea, Gliricidia sepium, Cedrela odorata, Theobroma cacao). The plant material decomposition process of the species was monitored with decomposition bags after 8, 15, 23, 84 and 113 days, evaluating remnant weight and nitrogen, phosphorous, potassium, calcium and magnesium content. Results showed significant differences in plant material decomposition of the species considered. The largest weight loss was found in G. arborea (87.55%) and the lowest in C. odorata (40.01%). The highest nutrient release value was found in G. arborea followed by G. sepium, and the lowest in T. cacao and C. odorata.Therefore, depending on the species that comprise the AFS there is a differential leaf biomass decomposition dynamic and hence, of the nutrient input to the soil. Of the species evaluated the highest input of new organic matter to the soil in this AFS comes from G. arborea. Altogether, the litter generated by the species evaluated contributed with 10% of the nutrients required for a cacao harvest.
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Sands, PJ, RN Cromer, and MUF Kirschbaum. "A Model of Nutrient Response in Eucalyptus grandis Seedlings." Functional Plant Biology 19, no. 5 (1992): 459. http://dx.doi.org/10.1071/pp9920459.
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Rate of growth in tree seedlings is dependent (amongst other factors) on the rate at which nutrients are absorbed by roots. Rate of nutrient addition to Eucalyptus grandis seedlings influences rate of growth through three main physiological mechanisms: the effects of plant nutrient concentration on biomass partitioning, specific leaf area, and assimilation. A simple dynamic model is presented to describe growth of E. grandis seedlings in response to different relative addition rates of nitrogen and phosphorus as reflected in plant nutrient status. The model takes account of effects of nutrient concentrations on partitioning, specific leaf area and light saturated assimilation rate. Model simulations demonstrate the influence relative nutrient addition rate has on key processes that influence relative growth rate, and that the relative importance of each of these is dependent on plant nutrient status. If plants are deficient in nitrogen, changes in growth consequent upon improved nutrient status are mediated primarily through effects on assimilate partitioning and light saturated assimilation rate. If plants have high nitrogen status, changes in growth consequent upon improved nutrient status are mediated primarily through effects on specific leaf area. If plants are deficient in phosphorus, changes in growth consequent upon improved nutrient status are mediated through effects on assimilation. If plants have high phosphorus status, changes in growth consequent upon improved nutrient status are mediated through effects on both assimilation and specific leaf area.
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Klimenko, Alexandra, Yury Matushkin, Nikolay Kolchanov, and Sergey Lashin. "Leave or Stay: Simulating Motility and Fitness of Microorganisms in Dynamic Aquatic Ecosystems." Biology 10, no. 10 (October 9, 2021): 1019. http://dx.doi.org/10.3390/biology10101019.
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Motility is a key adaptation factor in scarce marine environments inhabited by bacteria. The question of how a capacity for adaptive migrations influences the success of a microbial population in various conditions is a challenge addressed in this study. We employed the agent-based model of competition of motile and sedentary microbial populations in a confined aquatic environment supplied with a periodic batch nutrient source to assess the fitness of both. Such factors as nutrient concentration in a batch, batch period, mortality type and energetic costs of migration were considered to determine the conditions favouring different strategies: Nomad of a motile population and Settler of a sedentary one. The modelling results demonstrate that dynamic and nutrient-scarce environments favour motile populations, whereas nutrient-rich and stagnant environments promote sedentary microorganisms. Energetic costs of migration determine whether or not the Nomad strategy of the motile population is successful, though it also depends on such conditions as nutrient availability. Even without penalties for migration, under certain conditions, the sedentary Settler population dominates in the ecosystem. It is achieved by decreasing the local nutrient availability near the nutrient source, as motile populations relying on a local optimizing strategy tend to follow benign conditions and fail, enduring stress associated with crossing the valleys of suboptimal nutrient availability.
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Hosomi, M., M. Okada, and R. Sudo. "Assessment of Eutrophication Control Programs Using an Ecological Model for a Dimictic Lake." Water Science and Technology 24, no. 6 (September 1, 1991): 339–48. http://dx.doi.org/10.2166/wst.1991.0174.
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An ecological model of Lake Yunoko, a dimictic lake, was developed to assess various programs for eutrophication control. A multi-component dynamic model for nutrients in the bottom sediment-water system was incorporated into the model, a one-dimensional water temperature-water quality-ecological model. Good agreement between the model calculations and observed nutrients, chlorophyll-a, and dissolved oxygen concentrations in the water and nutrient concentrations in the bottom sediment was noted. The agreement between the model calculations and the measured nutrient flux from bottom sediment during the summer stagnation period was good. The effectiveness of sediment dredging, artificial circulation, and reduction of external phosphorus loading as eutrophication control programs on chlorophyll-a, PO4−P, and dissolved oxygen concentration in the water was assessed using a calibrated model.
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Romero, E., F. Peters, and C. Marrasé. "Dynamic forcing of coastal plankton by nutrient imbalances and match-mismatch between nutrients and turbulence." Marine Ecology Progress Series 464 (September 19, 2012): 69–87. http://dx.doi.org/10.3354/meps09846.
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Benmoussa, Mohamed, and Laurent Gauthier. "Computer-based System for Dynamic Control of Greenhouse Tomato Grown in NFT System." HortScience 30, no. 4 (July 1995): 847F—847. http://dx.doi.org/10.21273/hortsci.30.4.847f.
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To achieve high yield and better quality of soilless greenhouse tomato, it is necessary to keep the nutrient concentrations in the root environment at the target levels. Dynamic control of the nutrient solution composition can be used for this purpose. We developed a computer program that dynamically adjusts nutrient solution compositions based on various climatic and agronomic characteristics. The program integrates nutrient uptake and crop transpiration models and is part of a general-purpose greenhouse management and control software system developed at Laval University (GX). The architecture of the system and some simulation results comparing the effect of various control scenarios on the evolution of the composition of nutrient solutions are presented.
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Rankinen, Katri, Eila Turtola, Riitta Lemola, Martyn Futter, and José Enrique Cano Bernal. "Nutrient Load Mitigation with Wintertime Cover as Estimated by the INCA Model." Water 13, no. 4 (February 9, 2021): 450. http://dx.doi.org/10.3390/w13040450.
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Increased nutrient loading causes deterioration of receiving surface waters in areas of intensive agriculture. While nitrate and particulate phosphorus load can be efficiently controlled by reducing tillage frequency and increasing vegetation cover, many field studies have shown simultaneously increased loading of bioavailable phosphorus. In the latest phase of the Rural Programme of EU agri-environmental measures, the highest potential to reduce the nutrient loading to receiving waters were the maximum limits for fertilization of arable crops and retaining plant cover on fields with, e.g., no-till methods and uncultivated nature management fields. Due to the latter two measures, the area of vegetation cover has increased since 1995, suggesting clear effects on nutrient loading in the catchment scale as well. We modeled the effectiveness of agri-environmental measures to reduce phosphorus and nitrogen loads to waters and additionally tested the performance of the dynamic, process-based INCA-P (Integrated Nutrients in Catchments—Phosphorus) model to simulate P dynamics in an agricultural catchment. We concluded that INCA-P was able to simulate both fast (immediate) and slow (non-immediate) processes that influence P loading from catchments. Based on our model simulations, it was also evident that no-till methods had increased bioavailable P load to receiving waters, even though total P and total N loading were reduced.
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Shahzad, Raheel, Putri Widyanti Harlina, Mohammed Ayaad, Mohamed Ewas, Elsayed Nishawy, Shah Fahad, Hizar Subthain, and Mohamed H. Amar. "Dynamic roles of microRNAs in nutrient acquisition and plant adaptation under nutrient stress: A review." Plant Omics 11, no. 01 (February 20, 2018): 58–79. http://dx.doi.org/10.21475/poj.11.01.18.pne1014.
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Safferman, Steven I. "Selection of Nutrients to Enhance Biodegradation for the Remediation of Oil Spilled on Beaches1." International Oil Spill Conference Proceedings 1991, no. 1 (March 1, 1991): 571–76. http://dx.doi.org/10.7901/2169-3358-1991-1-571.
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ABSTRACT Laboratory studies were conducted to determine the fate of fertilizers proposed for application to the Alaska shoreline in support of the Alaskan Oil Spill EPA Bioremediation Project. Fertilizer application is thought to provide indigenous organisms with nutrients that appear to be limited on ocean beaches. The experiments were developed strictly to test the durability, release rates, and application procedures of a variety of fertilizer types. The effects of tidal movement on a beach were simulated by two separate conditions, static and dynamic. The static condition represented periods when the beach material was under water and turbulence was at a minimum. This condition was simulated in the laboratory by submerging the nutrient in a beaker of simulated seawater (with or without beach material, depending on the nutrients being tested). These experiments ran continuously over a three-month period, with water exchanges according to a planned schedule. Nutrient concentrations were measured in the exchanged water. Dynamic conditions represented the forces on beach material as the water moved from low to high tide and back to low tide. In the laboratory, the condition was simulated by applying the nutrients to beach material piled in one end of a long, narrow tray placed on a rocker table. When the rocker table was operating and enough seawater had been added to cover the beach material (in the rocker table's low position), a gentle sloshing of the water over the materials resulted. These experiments generally lasted one to two hours, during which time liquid samples were collected for nutrient analyses. Durability of the fertilizers was measured by visual observation and freeze/thaw determinations. The experimental setup was economical and performed well. The fertilizer most suited for field trial was found to be isobutyraldehyde diurea briquettes, which produced a slow, continuous release of nutrients.
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Pang, H., M. Makarechian, J. A. Basarab, and R. T. Berg. "Structure of a dynamic simulation model for beef cattle production systems." Canadian Journal of Animal Science 79, no. 4 (December 1, 1999): 409–17. http://dx.doi.org/10.4141/a99-020.
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A dynamic deterministic model for simulating beef cattle production systems is developed to evaluate the effects of production traits and management strategies on the bioeconomic efficiency of beef production systems. The model, named Alberta Beef Production Simulation System (ABPSS), is composed of four major submodels: herd inventory, nutrient requirement, forage production, and economic submodels. The herd inventory submodel is used to simulate population dynamics and feed requirements in the herd. The nutrient requirements submodel is mainly based on the 1996 version of the National Research Council (NRC). It is used to evaluate nutrients and feed requirements for calves and cows depending on their physiological status (maintenance, growth, lactation and gestation) and the climatic condition. The forage production sub-model is used to predict forage growth rate, cattle grazing rate, available forage biomass and total hectares required for grazing. The economic submodel measures bioeconomic efficiency, as net return per cow, by subtracting total cost from total return. The nutrient requirements predicted by ABPSS were compared with those recommended by the NRC for testing. The results that were predicted by the NRC model and ABPSS model were similar, as expected. Sensitivity analyses showed that cow mature weight, milk production, calf weaning weight and feed prices were the most critical input parameters in the model. It must be noted that the model was developed based on available experimental results and data from the literature and, due to the unavailability of a suitable data set, the model could not be validated. We suggest that the ABPSS has the potential for providing a useful method for simultaneous consideration of many factors in an integrated system, which could be helpful to beef cattle extension specialists and cow-calf production managers for assessing the potential effects of different management and selection strategies on bioeconomic efficiency. Key words: Beef cattle, simulation and modelling, production system, optimization
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Novriyanti, E., M. Watanabe, Q. Mao, and K. Takayoshi. "Growth performance of eucalypts and acacia seedling under elevated CO2 load in the changing environment." IOP Conference Series: Earth and Environmental Science 918, no. 1 (November 1, 2021): 012030. http://dx.doi.org/10.1088/1755-1315/918/1/012030.
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Abstract Acacia and Eucalypt are important species in the global forest plantations. The resilience of those species under the changing environment would define their significance in the dynamic of forest plantation. This study was aimed to provide information on the growth performance of two acacias and two eucalypts seedlings under elevated CO2 concentrations. The seedlings of A. auriculiformis, A. mangium, E. camadulensis, and E. urophylla were subjected to two levels of CO2 and two levels of nutrient supply in the FACE system in Sapporo Experimental Forest, Japan. The eucalypts showed significantly higher growth performance than the acacias. The nutrient addition significantly increased the growth, yet the CO2 and interaction between CO2 and nutrients were not significantly different. LMA was not significantly affected by the elevated CO2 and nutrient addition. Although nutrients significantly affected the C/N in the eucalypts, they showed no different effect on the acacias. As expected, Nmass and Narea were higher in the acacia than those in the eucalypts, although no significant responses were shown to elevated CO2 and nutrient addition. The tested acacia and eucalypts showed relatively insensitivity to elevated CO2. Thus they might possess resilience capacity under the keep increasing level of the atmospheric CO2 concentration.
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O'Brien, Katherine R., Tony R. Weber, Catherine Leigh, and Michele A. Burford. "Sediment and nutrient budgets are inherently dynamic: evidence from a long-term study of two subtropical reservoirs." Hydrology and Earth System Sciences 20, no. 12 (December 13, 2016): 4881–94. http://dx.doi.org/10.5194/hess-20-4881-2016.
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Abstract. Accurate reservoir budgets are important for understanding regional fluxes of sediment and nutrients. Here we present a comprehensive budget of sediment (based on total suspended solids, TSS), total nitrogen (TN) and total phosphorus (TP) for two subtropical reservoirs on rivers with highly intermittent flow regimes. The budget is completed from July 1997 to June 2011 on the Somerset and Wivenhoe reservoirs in southeast Queensland, Australia, using a combination of monitoring data and catchment model predictions. A major flood in January 2011 accounted for more than half of the water entering and leaving both reservoirs in that year, and approximately 30 % of water delivered to and released from Wivenhoe over the 14-year study period. The flood accounted for an even larger proportion of total TSS and nutrient loads: in Wivenhoe more than one-third of TSS inputs and two-thirds of TSS outputs between 1997 and 2011 occurred during January 2011. During non-flood years, mean historical concentrations provided reasonable estimates of TSS and nutrient loads leaving the reservoirs. Calculating loads from historical mean TSS and TP concentrations during January 2011, however, would have substantially underestimated outputs over the entire study period, by up to a factor of 10. The results have important implications for sediment and nutrient budgets in catchments with highly episodic flow. First, quantifying inputs and outputs during major floods is essential for producing reliable long-term budgets. Second, sediment and nutrient budgets are dynamic, not static. Characterizing uncertainty and variability is therefore just as important for meaningful reservoir budgets as accurate quantification of loads.
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Leitner, D., S. Klepsch, M. Ptashnyk, A. Marchant, G. J. D. Kirk, A. Schnepf, and T. Roose. "A dynamic model of nutrient uptake by root hairs." New Phytologist 185, no. 3 (December 17, 2009): 792–802. http://dx.doi.org/10.1111/j.1469-8137.2009.03128.x.
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尚, 荣忠. "Dynamic Analysis of a Time Delayed Nutrient-Phytoplankton System." Advances in Applied Mathematics 06, no. 02 (2017): 165–73. http://dx.doi.org/10.12677/aam.2017.62019.
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Qi, Qimo, Yu Li, Fanzhi Meng, Guangping Xing, Jilei Zhou, and Xianfeng Guo. "Dynamic changes of nutrient content in herbaceous peony seed." Oil Crop Science 5, no. 2 (May 2020): 36–41. http://dx.doi.org/10.1016/j.ocsci.2020.05.001.
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Chen, Xi, Yanhua Wang, Tian Sun, Yu Huang, Yan Chen, Mingli Zhang, and Chun Ye. "Effects of Sediment Dredging on Nutrient Release and Eutrophication in the Gate-Controlled Estuary of Northern Taihu Lake." Journal of Chemistry 2021 (January 19, 2021): 1–13. http://dx.doi.org/10.1155/2021/7451832.
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Estuarine zones are regarded as the ecotones connecting the rivers and lakes. Sediment dredging is a conventional treatment technology that is widely used to remove the internal loading in estuarine zones worldwide. However, what is the characteristic of nutrient release in the gate-controlled estuary and how long this practice is effective are still unclear. Hence, sediment and water samples were collected from dredged and undredged regions around the gate-controlled estuary of northern Taihu Lake for laboratory experiments, in which they were subjected to different temperatures, depths, and disturbance levels. The total nitrogen (TN) and total phosphorus (TP) concentrations of the dredged region were lower than those from the undredged region under stable hydrodynamic conditions. A high dynamic release rate (R) of nutrients in the dredged sediments (RTN = 164.75 mg/m2·d and RTP = 5.83 mg/m2·d) existed under dynamic release conditions (stirring speeds: 90 and 120 r/min). The effect of disturbance and temperature on release rate and nutrient form was completely different for the static and dynamic release cases. The nutrient loads from dynamic release were 4–17 times greater than those from static release. For unstable hydrodynamic conditions, the release rate from the bottom sediment exceeded that from the surface sediment in the undredged region. These results indicated that, under stable hydrodynamic conditions, dredging improves long-term water quality. However, dredging alone in unstable hydrodynamic conditions may not remove the potential risk of internal release in the long term. Specific ecological and engineering measures should be combined with dredging practice to restore estuary habitats and minimize the release of internal pollutants.
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Schneider, Philip A., James W. Wallace, and Julian C. Tickle. "Modelling and dynamic simulation of struvite precipitation from source-separated urine." Water Science and Technology 67, no. 12 (June 1, 2013): 2724–32. http://dx.doi.org/10.2166/wst.2013.184.
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A model of a mixed-mode nutrient recovery reactor is developed for a urine feed, incorporating complex solution thermodynamics, dynamic conservation relations and a power-law kinetic expression for crystal growth from seed crystals. Simulations at nominal operating conditions predict phosphorus recoveries greater than 99%, based on existing process kinetic parameters and operating conditions employed in previously published studies. The overall rate of nutrient recovery depends on the saturation index of the precipitating solid, the available surface area for mass transfer and the feed rate of the limiting constituent ion. Under the conditions considered, the nutrient feed rate appears to be the limiting factor for precipitation. Simulations demonstrate that diurnal feed flow variations of ±50% have a small effect on the rate of nutrient recovery. Overall, the study shows that valuable insights are gained in relation to process performance predictions, which should lead to more confident process design, operation and control.
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Abbott, Lynette K., and David A. C. Manning. "Soil Health and Related Ecosystem Services in Organic Agriculture." Sustainable Agriculture Research 4, no. 3 (June 19, 2015): 116. http://dx.doi.org/10.5539/sar.v4n3p116.
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<p>Soil health is dependent upon complex bio-physical and bio-chemical processes which interact in space and time. Microrganisms and fauna in soil comprise highly diverse and dynamic communities that contribute, over either short or long time frames, to the transformation of geological minerals and release of essential nutrients for plant growth. Certified organic soil management practices generally restrict the use of chemically-processed highly soluble plant nutrients, leading to dependence on nutrient sources that require microbial transformation of poorly soluble geological minerals. Consequently, slow release of nutrients controls their rate of uptake by plants and associated plant physiological processes. Microbial and faunal interactions influence soil structure at various scales, within and between crystalline mineral grains, creating complex soil pore networks that further influence soil function, including the nutrient release and uptake by roots. The incorporation of organic matter into soil, as either manure or compost in organic farming systems is controlled to avoid excessive release of soluble nutrients such as nitrogen and phosphorus, while simultaneously contributing an essential source of carbon for growth and activity of soil organisms. The interdependence of many soil physical and chemical processes contributing to soil health is strongly linked to activities of the organisms living in soil as well as to root structure and function. Capitalizing on these contributions to soil health cannot be achieved without holistic, multiscale approaches to nutrient management, an understanding of interactions between carbon pools, mineral complexes and soil mineralogy, and detailed examination of farm nutrient budgets.</p>
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Awal, Ripendra, Almoutaz El Hassan, Farhat Abbas, Ali Fares, Haimanote K. Bayabil, Ram L. Ray, and Selamawit Woldesenbet. "Patterns of Nutrient Dynamics within and below the Rootzone of Collard Greens Grown under Different Organic Amendment Types and Rates." Sustainability 13, no. 12 (June 17, 2021): 6857. http://dx.doi.org/10.3390/su13126857.
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The knowledge about nutrient dynamics in the soil is pivotal for sustainable agriculture. A comprehensive research trial can retort unanswered questions. Dynamics of nutrients sourced from organic amendment types (chicken manure, dairy manure, and MilorganiteTM) applied at different rates (0, 168, 336, 672 kg total N/ha) were monitored within and below the rootzone of collard greens cultivated on a sandy loam soil in Prairie View, TX, USA. Macro- and micronutrients (e.g., TN: total nitrogen, P: phosphorous, K: potassium, Na: sodium, Ca: calcium, Mg: magnesium, B: boron, Cu: copper, Fe: iron, and Zn: zinc) were analyzed from soil solution samples collected during six sampling periods from within and below the rootzone. As hypothesized, the organic amendment types and rates significantly (p < 0.05 and/or 0.01) affected nutrient dynamics within and below the crop rootzone. Chicken manure released significantly more TN, P, K, Na, Ca, Mg, B, Cu, and Fe than the other two amendments. The application of chicken manure and MilorganiteTM resulted in higher below-the-rootzone leachate concentration of TN, Na, Mg, and Ca than in the leachates of dairy manure. Dairy manure treatments had the lowest concentrations of TN, Ca, and Mg; whereas, MilorganiteTM had the lowest concentrations of P, K, Na, B, and Cu in the collected leachates. The higher level of P (i.e., 4% in MilorganiteTM as compared to 2 and 0.5% in chicken and dairy manures, respectively, might have reduced the formation of Vesicular-Arbuscular (VA) mycorrhizae—a fungus with the ability to dissolve the soil P, resulting in slow release of P from MilorganiteTM treatment than from the other two treatments. Patterns of nutrient dynamics varied with rain and irrigation events under the effects of the soil water and time lapse of the amendment applications’ rates and types. All the macronutrients were present within the rootzone and leached below the rootzone, except Na. The dynamic of nutrients was element-specific and was influenced by the amendments’ type and application rate.
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Sawyer, L. K., and S. W. Hermanowicz. "Detachment of Aeromonas hydrophila and Pseudomonas aeruginosa due to variations in nutrient supply." Water Science and Technology 41, no. 4-5 (February 1, 2000): 139–45. http://dx.doi.org/10.2166/wst.2000.0437.
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Growth and detachment rates of Aeromonas hydrophila and Pseudomonas aeruginosa were measured to determine if nutrient depletion causes detachment of attached cells. A glass parallel plate, continuous observation flow cell placed on a phase contrast microscope was used to monitor bacterial behaviour on the surface under defined flow and mass transfer conditions. Shear stress was held constant at 3 N m−2. Images were taken every 15 minutes, and digital image analysis was used to quantify specific growth, detachment and accumulation rates for the attached organisms. An observable parameter proportional to the nutrient depletion at the surface was used to determine the effect of nutrient depletion on detachment rates. Increases in the depletion parameter corresponded with increases in detachment rate after the cells were rod, but the depletion parameter was not scaleable between different experiments. These experiments showed that as nutrients were depleted, detachment increased. If the detachment mechanism postulated in this work is more universal and applicable to other microbial species, new methods of detachment control through dynamic changes of nutrient supply might be devised.
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Shi, Handuo, Corey S. Westfall, Jesse Kao, Pascal D. Odermatt, Sarah E. Anderson, Spencer Cesar, Montana Sievert, et al. "Starvation induces shrinkage of the bacterial cytoplasm." Proceedings of the National Academy of Sciences 118, no. 24 (June 11, 2021): e2104686118. http://dx.doi.org/10.1073/pnas.2104686118.
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Environmental fluctuations are a common challenge for single-celled organisms; enteric bacteria such as Escherichia coli experience dramatic changes in nutrient availability, pH, and temperature during their journey into and out of the host. While the effects of altered nutrient availability on gene expression and protein synthesis are well known, their impacts on cytoplasmic dynamics and cell morphology have been largely overlooked. Here, we discover that depletion of utilizable nutrients results in shrinkage of E. coli’s inner membrane from the cell wall. Shrinkage was accompanied by an ∼17% reduction in cytoplasmic volume and a concurrent increase in periplasmic volume. Inner membrane retraction after sudden starvation occurred almost exclusively at the new cell pole. This phenomenon was distinct from turgor-mediated plasmolysis and independent of new transcription, translation, or canonical starvation-sensing pathways. Cytoplasmic dry-mass density increased during shrinkage, suggesting that it is driven primarily by loss of water. Shrinkage was reversible: upon a shift to nutrient-rich medium, expansion started almost immediately at a rate dependent on carbon source quality. A robust entry into and recovery from shrinkage required the Tol-Pal system, highlighting the importance of envelope coupling during shrinkage and recovery. Klebsiella pneumoniae also exhibited shrinkage when shifted to carbon-free conditions, suggesting a conserved phenomenon. These findings demonstrate that even when Gram-negative bacterial growth is arrested, cell morphology and physiology are still dynamic.
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Li, Y., G. Gal, V. Makler-Pick, A. M. Waite, L. C. Bruce, and M. R. Hipsey. "Examination of the role of the microbial loop in regulating lake nutrient stoichiometry and phytoplankton dynamics." Biogeosciences 11, no. 11 (June 5, 2014): 2939–60. http://dx.doi.org/10.5194/bg-11-2939-2014.
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Abstract. The recycling of organic material through bacteria and microzooplankton to higher trophic levels, known as the "microbial loop", is an important process in aquatic ecosystems. Here the significance of the microbial loop in influencing nutrient supply to phytoplankton has been investigated in Lake Kinneret (Israel) using a coupled hydrodynamic–ecosystem model. The model was designed to simulate the dynamic cycling of carbon, nitrogen and phosphorus through bacteria, phytoplankton and zooplankton functional groups, with each pool having unique C : N : P dynamics. Three microbial loop sub-model configurations were used to isolate mechanisms by which the microbial loop could influence phytoplankton biomass, considering (i) the role of bacterial mineralisation, (ii) the effect of micrograzer excretion, and (iii) bacterial ability to compete for dissolved inorganic nutrients. The nutrient flux pathways between the abiotic pools and biotic groups and the patterns of biomass and nutrient limitation of the different phytoplankton groups were quantified for the different model configurations. Considerable variation in phytoplankton biomass and dissolved organic matter demonstrated the sensitivity of predictions to assumptions about microbial loop operation and the specific mechanisms by which phytoplankton growth was affected. Comparison of the simulations identified that the microbial loop most significantly altered phytoplankton growth by periodically amplifying internal phosphorus limitation due to bacterial competition for phosphate to satisfy their own stoichiometric requirements. Importantly, each configuration led to a unique prediction of the overall community composition, and we conclude that the microbial loop plays an important role in nutrient recycling by regulating not only the quantity, but also the stoichiometry of available N and P that is available to primary producers. The results demonstrate how commonly employed simplifying assumptions about model structure can lead to large uncertainty in phytoplankton community predictions and highlight the need for aquatic ecosystem models to carefully resolve the variable stoichiometry dynamics of microbial interactions.
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Li, Y., G. Gal, V. Makler-Pick, A. M. Waite, L. C. Bruce, and M. R. Hipsey. "A numerical analysis of the role of the microbial loop in regulating nutrient stoichiometry and phytoplankton dynamics in a eutrophic lake." Biogeosciences Discussions 10, no. 12 (December 16, 2013): 19731–72. http://dx.doi.org/10.5194/bgd-10-19731-2013.
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Abstract. The recycling of organic material through bacteria and microzooplankton to higher trophic levels, known as the "microbial loop", is an important process in aquatic ecosystems. Here the significance of the microbial loop in influencing nutrient supply to phytoplankton is investigated in Lake Kinneret (Israel) using a coupled hydrodynamic-ecosystem model. The model was designed to simulate the dynamic cycling of carbon, nitrogen and phosphorus through bacteria, phytoplankton and zooplankton functional groups, with each pool having unique C : N : P dynamics. Three microbial loop sub-model configurations were used to isolate mechanisms by which the microbial loop could influence phytoplankton biomass, considering: (i) the role of bacterial mineralization, (ii) bacterial ability to compete for dissolved inorganic nutrients, and (iii) the effect of micrograzer excretion. The nutrient flux pathways between the abiotic pools and biotic groups and the patterns of biomass and nutrient limitation of the different phytoplankton groups were quantified for the different model configurations. Considerable variation in phytoplankton biomass and dissolved organic matter demonstrated the sensitivity of predictions to assumptions about microbial loop operation and the specific mechanisms by which phytoplankton growth was affected. Comparison of the simulations identified that the microbial loop most significantly altered phytoplankton growth by periodically amplifying internal phosphorus limitation due to bacterial competition for phosphate to satisfy their own stoichiometric requirements. Importantly, each configuration led to a unique prediction of the overall community composition, and we conclude that the microbial loop plays an important role in nutrient recycling by regulating not only the quantity, but also the stoichiometry of available N and P that is available to primary producers. The results demonstrate how commonly employed simplifying assumptions about model structure can lead to large uncertainty in phytoplankton community predictions and highlight the need for aquatic ecosystem models to carefully resolve the variable stoichiometry dynamics of microbial interactions.
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段, 涵. "Related Dynamic Analysis of a Nutrient-Phytoplankton Dynamic System under State Impulsive Feedback Control." Advances in Applied Mathematics 07, no. 02 (2018): 145–51. http://dx.doi.org/10.12677/aam.2018.72018.
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Li, Yuzhao, Yong Liu, Lei Zhao, Alan Hastings, and Huaicheng Guo. "Exploring change of internal nutrients cycling in a shallow lake: A dynamic nutrient driven phytoplankton model." Ecological Modelling 313 (October 2015): 137–48. http://dx.doi.org/10.1016/j.ecolmodel.2015.06.025.
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Jiménez, S., B. M. Plaza, and M. T. Lao. "Nutrient Solution and Nutrient Soil Solution Parameter Evolution in Tomato with Dynamic Fertigation under Saline Conditions." Communications in Soil Science and Plant Analysis 43, no. 1-2 (January 2012): 265–71. http://dx.doi.org/10.1080/00103624.2011.638588.
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Hornung, Raphael, Alexander Grünberger, Christoph Westerwalbesloh, Dietrich Kohlheyer, Gerhard Gompper, and Jens Elgeti. "Quantitative modelling of nutrient-limited growth of bacterial colonies in microfluidic cultivation." Journal of The Royal Society Interface 15, no. 139 (February 2018): 20170713. http://dx.doi.org/10.1098/rsif.2017.0713.
Full textAbstract:
Nutrient gradients and limitations play a pivotal role in the life of all microbes, both in their natural habitat as well as in artificial, microfluidic systems. Spatial concentration gradients of nutrients in densely packed cell configurations may locally affect the bacterial growth leading to heterogeneous micropopulations. A detailed understanding and quantitative modelling of cellular behaviour under nutrient limitations is thus highly desirable. We use microfluidic cultivations to investigate growth and microbial behaviour of the model organism Corynebacterium glutamicum under well-controlled conditions. With a reaction–diffusion-type model, parameters are extracted from steady-state experiments with a one-dimensional nutrient gradient. Subsequently, we employ particle-based simulations with these parameters to predict the dynamical growth of a colony in two dimensions. Comparing the results of those simulations with microfluidic experiments yields excellent agreement. Our modelling approach lays the foundation for a better understanding of dynamic microbial growth processes, both in nature and in applied biotechnology.