scholarly journals ABIOTIC FACTORS AFFECTING THE ECOLOGICAL STATE OF LAKE NERO ACCORDING TO MATHEMATICAL MODELING. 1. NUTRIENT LOAD FROM THE CATCHMENT AREA

2020 ◽  
pp. 19-27
Author(s):  
Sh. Pozdnyakov ◽  
S. Kondratiev ◽  
M. Shmakova
Keyword(s):  
External Load ◽  
Quantitative Assessment ◽  
Drainage Basin ◽  
Abiotic Factors ◽  
Aquatic Area ◽  
Nutrient Load ◽  
Large Area ◽  
Nitrogen And Phosphorus ◽  
Total Load ◽  
Best Available Technologies

Reducing the external load is an uncontested method of reducing the rate of anthropogenic eutrophication of the lake, since the possibilities of real impact aimed at reducing the internal load over a large area are extremely limited. The purpose of this study is a quantitative assessment of the external load of nitrogen and phosphorus on Lake Nero from the drainage basin in modern conditions. The assessment of the nutrient load from the drainage area of Lake Nero was carried out according to the mathematical model of the formation of the nutrient load, developed at the Institute of Limnology of the Russian Academy of Sciences. The model is designed to solve problems related to the quantitative assessment of the external load on water bodies, formed by point and nonpoint sources of pollution, forecast of its change under the influence of possible anthropogenic and climatic changes, taking into account the influence of hydrological factors and the retention of nutrients by the catchment and the hydrographic network. It was found that the load on the aquatic area from the catchment is 51.5 t P / year and 585.5 t N / year, of which 36.0 t P / year (70% of the total load on the lake) and 176.5 t N / year (30%) go directly to lake from coastal settlements. Provided that the entire population is connected to treatment facilities and the introduction of best available technologies (BAT) for agriculture, according to a numerical experiment, the load will decrease by 23% for total phosphorus and 19% for total nitrogen.

scholarly journals Aquaculture Feeds Can Be Outlaws for Eutrophication When Hidden in Rice Fields? A Case Study in Qianjiang, China

2019 ◽  
Vol 16 (22) ◽  
pp. 4471 ◽  
Author(s):  
Liu ◽  
Hu ◽  
Song ◽  
Chen ◽  
Zhu
Keyword(s):  
Rural Areas ◽  
Local Governments ◽  
Irrigation System ◽  
Material Balance ◽  
Rice Production ◽  
Integrated System ◽  
Large Area ◽  
Nitrogen And Phosphorus ◽  
Output Analysis ◽  
Water Eutrophication

Water eutrophication caused by agricultural production has become one of the most important factors that impede sustainable rural environmental governance in China. As a result, the Chinese central and local governments want to reduce the use of nitrogen and phosphorus fertilizer and gain socioeconomical profit simultaneously by promoting crayfish and rice integrated system (CRIS) in the rural areas with abundant water resources. In this article, we investigated whether CRIS in Qianjiang, Hubei, the origin place of the system in China, contributes to fulfilling the governments’ expectations. We found that CRIS efficaciously cuts the fertilizer rate in rice production and boosts farmers’ incomes because crayfish has a demand for water quality and holds a large internal market requirement. However, higher profit encourages farmers to expand crayfish production and thus discourages the initiatives in rice production. The area of the ditch for crayfish production expands ceaselessly and exceeds the limit of regulation of CRIS. As a result, the CRIS in the areas has emerged as a practice of aquaculture but in farmland. This is a regulatory gap. The input–output analysis of CRIS by material balance method can also reveal that excessive feed for crayfish has become a new source of agricultural pollution. Beyond that, due to the changed irrigation system and increased water exchange frequency of CRIS, the pollution has transformed from passive distribution to active, which will increase the risk of water eutrophication on a large area.

scholarly journals Accelerometry-Based External Load Indicators in Sport: Too Many Options, Same Practical Outcome?

2019 ◽  
Vol 16 (24) ◽  
pp. 5101 ◽  
Author(s):  
Carlos D. Gómez-Carmona ◽  
José Pino-Ortega ◽  
Braulio Sánchez-Ureña ◽  
Sergio J. Ibáñez ◽  
Daniel Rojas-Valverde
Keyword(s):  
Literature Review ◽  
External Load ◽  
Total Load ◽  
Sport Science ◽  
Z Scores ◽  
Data Points ◽  
Impulse Load ◽  
Soccer Team

With the development of new microsensor technology to assess load in sports, some indicators of external load through accelerometry-based data have been created by sport technology companies. Thus, the study aim was to analyze the agreement between different accelerometry-based external load indicators (ABELIs) available in sport science. A U-16 male soccer team was assessed during three official matches, divided by periods, to obtain 3-D accelerometry data (x, y and z axes). An average of 1,420,000 data points was analyzed per axis per player. The ABELIs were calculated using this information, and the agreement between them was explored. The following ABELIs were considered after a literature review: AcelT, Player LoadRT, PlayerLoadTM, Impulse Load, Player LoadRE and Total Load. In order to compare ABELIs, two analyses were performed using: (1) absolute data; and (2) normalized and centered data (Z-scores). In absolute and centered data, very large to nearly perfect correlations (1st period: r > 0.803, p > 0.01; 2nd period: r > 0.919; p > 0.01) were found. Instead, very large differences were found in absolute values (bias = −579,226.6 to 285,931.1; t = −224.66 to 213.91, p < 0.01), and no differences in scaled and centered values (bias = 0; t = 1; p = 1). In conclusion, considering the different output (magnitude and units) among ABELIs, the standardization of a universal index to calculate accelerometer load is needed in order to make possible between-study comparison.

scholarly journals Diversity and spatial distribution of black flies (Diptera: Simuliidae) in the Ijuí river drainage basin, Rio Grande do Sul, Brazil

2019 ◽  
Vol 12 (2) ◽  
pp. 47-56
Author(s):  
Tieli Cláudia Menzel ◽  
Sirlei Maria Hentges ◽  
David Augusto Reynalte Tataje ◽  
Milton Norberto Strieder
Keyword(s):  
River Basin ◽  
Indicator Species ◽  
Drainage Basin ◽  
Abiotic Factors ◽  
Principal Component ◽  
Rio Grande ◽  
Anthropogenic Pressure ◽  
Black Flies ◽  
Rio Grande Do Sul ◽  
Significant Difference

Abstract. In southern Brazil there are several problems regarding the hematophageal activity of black flies, and the information on the distribution of species are still insufficient. In this study, our main goals were to recognize Simuliidae species and to analyze abiotic factors regarding the distribution of immature stages (larva and pupa) in streams from the Ijuí River basin, Northwest of Rio Grande do Sul, Brazil. We sampled simulids specimens in 27 study sites, covering three regions (high, intermediate and low altitude). Concomitantly, we recorded abiotic factors in the studied sites, such as: temperature, electrical conductivity, dissolved oxygen, atmospheric pressure, pH, altitude and stream width. For data analysis, we performed Kruskal-Wallis, ANOVA, Principal Component Analysis (PCA), Analysis of Indicator Species and Canonical Correspondence (CCA). A total of 10 species of black Flies was recorded. Simulium pertinax Kollar, Simulium incrustatum Lutz and Simulium orbitale Lutz were the most frequent. There was no significant difference in richness and density of the species between the different regions studied, except for Simulium jujuyense Paterson & Shannon. The sampled environments were segregated according to the location within the basin, and only S. jujuyense was considered an indicator species of the upper region. These results can be explained by the homogeneous conditions of the Ijuí River basin, which have suffered anthropogenic pressure mainly due to agricultural activities, resulting in losses in local aquatic biodiversity. Also, it may indicate that the control must be conducted considering the basin as a whole, and not only as isolated stretches of the streams.Diversidade e distribuição espacial de borrachudos (Diptera: Simuliidae) na bacia hidrográfica do rio Ijuí, Rio Grande do Sul, BrasilResumo. No sul do Brasil existem problemas com atividade hematofágica de borrachudos e as informações referentes à distribuição das espécies ainda são insuficientes. O presente estudo visa reconhecer as espécies de Simuliidae e analisar fatores abióticos quanto a distribuição dos estágios imaturos (larva e pupa) em riachos da Bacia do Rio Ijuí, no Noroeste do Rio Grande do Sul, Brasil. Foram coletados simulídeos em 27 pontos de estudo, cobrindo três regiões da bacia (alta, intermediária e baixa altitude). Concomitantemente, foi feito o registro de fatores abióticos nos trechos estudados, tais como: temperatura, condutividade elétrica, oxigênio dissolvido, pressão atmosférica, pH, altitude e largura do riacho. Foram realizadas análises de Kruskal-Wallis ou ANOVA, Análise de Componentes Principais (PCA), Análise de Espécie Indicadora e de Correspondência Canônica (CCA). Foi registrado um total de 10 espécies de Simuliidae. Simulium pertinax Kollar, Simulium incrustatum Lutz e Simulium orbitale Lutz foram as mais frequentes. Não ocorreu diferença na riqueza e na densidade das espécies entre as diferentes regiões estudadas, exceto para Simulium jujuyense Paterson & Shannon. Os ambientes nos pontos de amostragem foram segregados de acordo com a sua localização na bacia, e apenas S. jujuyense foi considerada uma espécie indicadora da região alta. Tais resultados podem ser explicados pelas condições homogêneas da Bacia do Rio Ijuí, que vêm sofrendo pressão antropogênica principalmente devido às atividades agrícolas, resultando em perdas na biodiversidade aquática local. Também, indicam que o controle deve ser realizado considerando a bacia como um todo e não apenas em trechos isolados dos riachos.

Mitigating a global expansion of toxic cyanobacterial blooms: confounding effects and challenges posed by climate change

2020 ◽  
Vol 71 (5) ◽  
pp. 579 ◽  
Author(s):  
Hans W. Paerl ◽  
Karl. E. Havens ◽  
Nathan. S Hall ◽  
Timothy G. Otten ◽  
Mengyuan Zhu ◽  
...  
Keyword(s):  
Climate Change ◽  
Algal Blooms ◽  
Synergistic Effects ◽  
Cyanobacterial Blooms ◽  
Extreme Weather Events ◽  
Nutrient Load ◽  
Nitrogen And Phosphorus ◽  
Sediment Dredging ◽  
Fish Removal ◽  
Global Expansion

Managing and mitigating the global expansion of toxic cyanobacterial harmful algal blooms (CyanoHABs) is a major challenge facing researchers and water resource managers. Various approaches, including nutrient load reduction, artificial mixing and flushing, omnivorous fish removal, algaecide applications and sediment dredging, have been used to reduce bloom occurrences. However, managers now face the additional challenge of having to address the effects of climate change on watershed hydrological and nutrient load dynamics, water temperature, mixing regime and internal nutrient cycling. Rising temperatures and increasing frequencies and magnitudes of extreme weather events, including tropical cyclones, extratropical storms, floods and droughts, all promote CyanoHABs and affect the efficacy of ecosystem remediation measures. These climatic changes will likely require setting stricter nutrient (including both nitrogen and phosphorus) reduction targets for bloom control in affected waters. In addition, the efficacy of currently used methods to reduce CyanoHABs will need to be re-evaluated in light of the synergistic effects of climate change with nutrient enrichment.

Contribution of nitrogen and phosphorus by precipitation in the drainage basin of the Santillana Reservoir (Madrid)

1994 ◽  
Vol 23 (2) ◽  
pp. 99-104 ◽  
Author(s):  
B. Lacalle Pareja ◽  
C. G�mez Artola ◽  
F. L�pez Vera
Keyword(s):  
Drainage Basin ◽  
Nitrogen And Phosphorus

Modeling water and nutrients fluxes in the Büyük Menderes drainage basin, Turkey

2009 ◽  
Vol 59 (3) ◽  
pp. 531-541 ◽  
Author(s):  
Ö. F. Durdu ◽  
V. Cvetkovic
Keyword(s):  
Point Source ◽  
Drainage Basin ◽  
Temporal Distribution ◽  
Aegean Sea ◽  
Nitrogen And Phosphorus ◽  
Industrial Sectors ◽  
Modeling Process ◽  
Nutrient Emissions ◽  
Catchment Modeling ◽  
River Loads

Büyük Menderes catchment, located in the southwestern part of Turkey, is one of the most populated river basins in Turkey with 2.5 millions inhabitants. Due to increasing activities in agriculture and industrial sectors, water resources management in the basin is one of the biggest matters for the future. During the past decade, it has been observed a basinwide shift to larger monocultural, intensively operated farm units. Therefore, there is land use conversion from native lands to agriculture. The threat of nutrients pollution, nitrogen and phosphorus, has become a preoccupation since many lands and rivers undergo a eutrophication process. The discharge of nutrients from Büyük Menderes basin to the Aegean Sea through Büyük Menderes river also needs to be reduced in order to bring the eutrophication problems under lasting control. In this paper, the PolFlow model embedded in PCraster is applied to the catchment for quantifying water and substances fluxes for the five-year period, 1999–2004. The implementation of the model in the catchment allows describing the water balance and thus nutrient transport on the landscape surface but also through the soil and aquifer's layers. Modeling process is complicated by the transfer of nutrients from diffuse and point-source emissions, managed by retention and periodic release from storages within the catchment. Modeling diffuse and point-source nutrient emissions contribution to river loads can be improved by better knowledge about spatial and temporal distribution of this retention and release in the basin.

scholarly journals Patterns in Ectomycorrhizal Diversity, Community Composition, and Exploration Types in European Beech, Pine, and Spruce Forests

Forests ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 445 ◽  
Author(s):  
Christoph Rosinger ◽  
Hans Sandén ◽  
Bradley Matthews ◽  
Mathias Mayer ◽  
Douglas Godbold
Keyword(s):  
Community Composition ◽  
Tree Species ◽  
Short Distance ◽  
Abiotic Factors ◽  
European Beech ◽  
Root Tips ◽  
Nitrogen And Phosphorus ◽  
Long Distance ◽  
Ectomycorrhizal Diversity ◽  
Exploration Types

Ectomycorrhizal (EM) fungi are pivotal drivers of ecosystem functioning in temperate and boreal forests. They constitute an important pathway for plant-derived carbon into the soil and facilitate nitrogen and phosphorus acquisition. However, the mechanisms that drive ectomycorrhizal diversity and community composition are still subject to discussion. We investigated patterns in ectomycorrhizal diversity, community composition, and exploration types on root tips in Fagus sylvatica,Picea abies, and Pinus sylvestris stands across Europe. Host tree species is the most important factor shaping the ectomycorrhizal community as well as the distribution of exploration types. Moreover, abiotic factors such as soil properties, N deposition, temperature, and precipitation, were found to significantly influence EM diversity and community composition. A clear differentiation into functional traits by means of exploration types was shown for all ectomycorrhizal communities across the three analyzed tree species. Contact and short-distance exploration types were clearly significantly more abundant than cord- or rhizomorph-forming long-distance exploration types of EM fungi. Medium-distance exploration types were significantly lower in abundance than contact and short-distance types, however they were the most frequent EM taxa and constituted nearly half of the EM community. Furthermore, EM taxa exhibit distinct ecological ranges, and the type of soil exploration seemed to determine whether EM taxa have small or rather big environmental ranges.

scholarly journals Parametric Analysis of Tensegrity Plate-Like Structures: Part 2—Quantitative Analysis

2021 ◽  
Vol 11 (2) ◽  
pp. 602
Author(s):  
Paulina Obara ◽  
Justyna Tomasik
Keyword(s):  
Quantitative Analysis ◽  
Linear Model ◽  
Material Properties ◽  
External Load ◽  
Parametric Analysis ◽  
Quantitative Assessment ◽  
Reliable Assessment ◽  
Non Linear

The study includes a parametric analysis of a group of tensegrity plate-like structures built with modified Quartex modules. The quantitative assessment, including the calculation of the structure’s response to constant loads, was carried out. A static parametric analysis was performed, with particular emphasis on the influence of the initial prestress level on the displacements, the effort, and the stiffness of the structure. A geometrical non-linear model was used in the analysis. A reliable assessment required introducing a parameter for determining the influence of the initial prestress level on the overall stiffness of the structure at a given load. The stiffness of the structure was found to depend not only on the geometry and material properties, but also on the initial prestress level and external load. The results show that the effect of the initial prestress on the overall stiffness of the structure is greater with less load and that the effect of load is most significant with low pre-stressing forces. The analysis demonstrates that the control of static parameters is possible only when infinitesimal mechanisms occur in the structure.

scholarly journals A phosphorus threshold for mycoheterotrophic plants in tropical forests

2017 ◽  
Vol 284 (1848) ◽  
pp. 20162093 ◽  
Author(s):  
Merlin Sheldrake ◽  
Nicholas P. Rosenstock ◽  
Daniel Revillini ◽  
Pål Axel Olsson ◽  
S. Joseph Wright ◽  
...  
Keyword(s):  
Abiotic Factors ◽  
Am Fungi ◽  
Natural Fertility ◽  
Phosphorus Concentration ◽  
Terrestrial Plants ◽  
Nitrogen And Phosphorus ◽  
Phosphorus Addition ◽  
Lowland Tropical Forest ◽  
Fertility Gradient ◽  
Abundance And Distribution

The majority of terrestrial plants associate with arbuscular mycorrhizal (AM) fungi, which typically facilitate the uptake of limiting mineral nutrients by plants in exchange for plant carbon. However, hundreds of non-photosynthetic plant species—mycoheterotrophs—depend entirely on AM fungi for carbon as well as mineral nutrition. Mycoheterotrophs can provide insight into the operation and regulation of AM fungal relationships, but little is known about the factors, fungal or otherwise, that affect mycoheterotroph abundance and distribution. In a lowland tropical forest in Panama, we conducted the first systematic investigation into the influence of abiotic factors on the abundance and distribution of mycoheterotrophs, to ask whether the availability of nitrogen and phosphorus altered the occurrence of mycoheterotrophs and their AM fungal partners. Across a natural fertility gradient spanning the isthmus of Panama, and also in a long-term nutrient-addition experiment, mycoheterotrophs were entirely absent when soil exchangeable phosphate concentrations exceeded 2 mg P kg −1 . Experimental phosphorus addition reduced the abundance of AM fungi, and also reduced the abundance of the specific AM fungal taxa required by the mycoheterotrophs, suggesting that the phosphorus sensitivity of mycoheterotrophs is underpinned by the phosphorus sensitivity of their AM fungal hosts. The soil phosphorus concentration of 2 mg P kg −1 also corresponds to a marked shift in tree community composition and soil phosphatase activity across the fertility gradient, suggesting that our findings have broad ecological significance.

Investigations into the Fat Pads of the Sole of the Foot: Heel Pressure Studies

Foot & Ankle ◽  
1992 ◽  
Vol 13 (5) ◽  
pp. 227-232 ◽  
Author(s):  
Melvin H. Jahss ◽  
Frederick Kummer ◽  
James D. Michelson
Keyword(s):  
Clinical Symptoms ◽  
Fat Pad ◽  
Large Area ◽  
Total Load ◽  
Anatomic Structure ◽  
Load Bearing ◽  
Heel Pad ◽  
Load Carrying ◽  
Fat Pads ◽  
Broad Region

The fat pads of the heel have a structure that is optimized for load bearing. In various diseases and aging, the load-carrying ability of the heel pad is clinically impaired. The loading pattern was examined in subjects having normal heel pads and those with atrophic heel pads, both with and without clinical symptoms. Normal heel pads showed a broad region of high pressure, which accounted for a high percentage of the total load transmission. In contrast, the atrophic heels showed a high but narrow peak pressure. However, most of the load was transmitted over a large area of low pressure. There was no difference between symptomatic and asymptomatic heels. The mechanical behavior of the fat pad is discussed with particular reference to the anatomic structure of the pads. Pad thickness and septal integrity are both important to the mechanical characteristics of the fat pad. The load-bearing patterns observed are discussed in terms of the mechanical components influencing fat pad resilience. These results have direct relevance to understanding the pathophysiology of heel pain secondary to degeneration of the fat pad.

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