Periphyton colonization and changes in the diatom assemblages of an artificial urban pond

2020 ◽  
Vol 193 (4) ◽  
pp. 313-326
Author(s):  
Lorena González-Paz ◽  
Salomé F.P. de Almeida ◽  
Isabel Pardo ◽  
Cristina Delgado
Keyword(s):  
Urban Areas ◽  
Dry Mass ◽  
Diatom Assemblages ◽  
Ceramic Tiles ◽  
Algae Biomass ◽  
The Third ◽  
Analysis Of Similarity ◽  
Artificial Ecosystems ◽  
Urban Pond ◽  
Northwest Iberian Peninsula

Artificial ecosystems are sometimes the only opportunity for citizens to experience nature. Maintaining their quality is essential for continuing to enjoy the ecosystem services. We studied an urban pond in the Northwest Iberian Peninsula (Aveiro, Portugal) as a model for testing the suitability of diatom assemblages and indices of water quality in these particular ecosystems. Weekly sampling of three replicas was performed over 28 days on stones and ceramic tiles in a shaded site (Site-SH) and in a sunnier one (Site-SU). The best model of the distance-based analysis included temperature and NH4+as the variables that best explained the diatom assemblages (R 2= 0.43). Chlorophyll-α taken as a proxy for algae biomass, and ash-free dry mass increased until the third week, when a turbid runoff entered the system. After this disturbance, chlorophyll-α increased only at Site-SH (from 14.4 mg m –2 to 62.4 mg m–2); ash-free dry mass increased at Site-SU (from 7.2 mg m–2 to 42.3 mg m–2). The Specific Polluosensitivity Index of the diatoms showed low values below 16 that further decreased with the incubation time. Shannon diversity did not vary between sites, while ANOSIM (analysis of similarity) enabled the identification of differences in the species composition among sites and over time. Cyclotella meneghiniana and Sellaphora nigri were abundant at both sites, but other species showed a prevalence to one of the sites: Nitzschia amphibia and Gomphonema parvulum dominated at site-SH, whereas Amphora pediculus and Grunowia solgensis were abundant at site-SU. This study provides evidence that the use of benthic diatoms is a useful tool for evaluating the ecological potential of artificial ecosystems. Moreover, such systems in the close vicinity of urban areas need better management and monitoring to reduce the risk of deterioration.

scholarly journals Ensuring Sustainable Urban Transformation in Indonesia

2020 ◽  
Vol 1 (2) ◽  
pp. 217-224
Author(s):  
B. Setiawan ◽  
Tri Mulyani Sunarharum
Keyword(s):  
Developing Countries ◽  
21St Century ◽  
Urban Areas ◽  
Urban Population ◽  
Third World ◽  
Developed Countries ◽  
Urban Transformation ◽  
The Third ◽  
The Many ◽  
The Third World

Of the many important events that occurred in the two decades of the 21st century, the process of accelerating urbanization—especially in third-world countries—became something quite phenomenal. It's never even happened before. In the early 2000s, only about 45 percent of the population in the third world lived in urban areas, by 2020 the number had reached about 55 percent. Between now and 2035 the percentage of the population living in urban areas will reach about 85 percent in developed countries. Meanwhile, in developing countries will reach about 65 percent. By 2035, it is also projected that about 80 percent of the world's urban population will live in developing countries' cities.

scholarly journals UNE ETUDE DES DETERMINISMES A LA BASE DE L’ECHEC SCOLAIRE LE CAS DES PAYS DU TIERS MONDE(1)

2018 ◽  
Vol 10 (2) ◽  
Author(s):  
M. P. K. Nzunga
Keyword(s):  
Rural Areas ◽  
Urban Areas ◽  
Third World ◽  
Efficient Solution ◽  
Language Of Instruction ◽  
Financial Status ◽  
The Third ◽  
The Family ◽  
The Third World ◽  
Culture Of Origin

Fare has been established as a major issue, in primary and secondary schools within the Third World countries. This work sets out to reveal the possible determinants of this phenomenon. A comparison between performance in the rural areas and the urban areas has produced a lot of data on the determinants of school failure and repetition. The researcher seeks to establish the link between failure and the level of intelligence of the learners, the language of instruction, the financial status of the family and the culture of origin. The researcher hopes that by so doing, it would be easier to find a practical and efficient solution, to this problem, which is a great stambling block in the Third World countries.

scholarly journals Technical note: A time-integrated sediment trap to sample diatoms for hydrological tracing

2020 ◽  
Vol 24 (10) ◽  
pp. 4709-4725
Author(s):  
Jasper Foets ◽  
Carlos E. Wetzel ◽  
Núria Martínez-Carreras ◽  
Adriaan J. Teuling ◽  
Jean-François Iffly ◽  
...  
Keyword(s):  
Water Quality Assessment ◽  
Technical Note ◽  
Sampling Effort ◽  
Terrestrial Environment ◽  
The Third ◽  
Run Off ◽  
Analysis Of Similarity ◽  
Sediment Data ◽  
Almost All ◽  
Diatom Community Composition

Abstract. Diatoms, microscopic single-celled algae, are present in almost all habitats containing water (e.g. streams, lakes, soil and rocks). In the terrestrial environment, their diversified species distributions are mainly controlled by physiographical factors and anthropic disturbances which makes them useful tracers in catchment hydrology. In their use as a tracer, diatoms are generally sampled in streams by means of an automated sampling method; as a result, many samples must be collected to cover a whole storm run-off event. As diatom analysis is labour-intensive, a trade-off has to be made between the number of sites and the number of samples per site. In an attempt to reduce this sampling effort, we explored the potential for the Phillips sampler, a time-integrated mass-flux sampler, to provide a representative sample of the diatom assemblage of a whole storm run-off event. We addressed this by comparing the diatom community composition of the Phillips sampler to the composite community collected by automatic samplers for three events. Non-metric multidimensional scaling (NMDS) showed that, based on the species composition, (1) all three events could be separated from each other, (2) the Phillips sampler was able to sample representative communities for two events and (3) significantly different communities were only collected for the third event. These observations were generally confirmed by analysis of similarity (ANOSIM), permutational multivariate analysis of variance (PERMANOVA), and the comparison of species relative abundances and community-derived indices. However, sediment data from the third event, which was sampled with automatic samplers, showed a large amount of noise; therefore, we could not verify if the Phillips sampler sampled representative communities or not. Nevertheless, we believe that this sampler could not only be applied in hydrological tracing using terrestrial diatoms, but it might also be a useful tool in water quality assessment.

Why Do People Migrate?

On the Move ◽  
2016 ◽  
Author(s):  
Filiz Garip
Keyword(s):  
United States ◽  
Rural Communities ◽  
Urban Areas ◽  
The United States ◽  
Family Ties ◽  
Small Minority ◽  
The Third ◽  
Majority Group ◽  
First Time ◽  
Over Time

This chapter provides an overview of the migration field, and a brief review of Mexico–U.S. migration flows up to 1965, the year the analysis here begins. It describes the data and methods that led the author to discover four groups among first-time migrants from Mexico to the United States between 1965 and 2010. The first cluster—mostly uneducated and poor men from rural communities—was the majority in the 1970s but dropped to a small minority by the 1990s. The second cluster—many of them teenage boys from relatively better-off families—peaked in the 1980s, becoming the majority group at that time, but declined consistently in size thereafter. The third cluster—mostly women with family ties to former migrants—was increasing slowly in size until it experienced a sudden spike in the early 1990s. And the fourth cluster—mostly educated men from urban areas—grew persistently over time, grabbing the majority status among all first-time migrants in the early 1990s.

Extraordinary Heterosis Found In A Forage Grass Hybrid, Festuca apennina × F. pratensis

2020 ◽  
Author(s):  
Beat Boller ◽  
David Kopecký
Keyword(s):  
Chromosome Doubling ◽  
Artificial Chromosome ◽  
Dry Mass ◽  
Hybrid Vigor ◽  
Hybrid Breeding ◽  
Forage Grass ◽  
Breeding Programs ◽  
The Third ◽  
Specific Trait ◽  
Second Year

Abstract Background: Heterosis (or hybrid vigor) is the over-performance of a hybrid over its parents in a specific trait or a set of traits. As such, hybrid breeding serves as a tool to efficiently trigger gains in breeding programs. Moreover, hybrids of genetically distant landraces, varieties or even species may become evolutionary successful. In Swiss alpine swards, we observed frequent prevalence of triploid hybrids of Festuca pratensis × F. apennina with outstanding competitiveness relative to their parental species in the sites of sympatric occurrence. Results: Observations of these highly vigorous hybrids prompted the study on their heterosis across various environmental conditions. Phenotypic observations during three years at four locations at different altitudes (from 200 m a.s.l. to 1850 m a.s.l.) have shown significant heterosis for dry biomass production at all sites during the first and second year, and at the mid- and high altitude sites also in the third year. At mid-altitude (1000 m a.s.l.), heterosis increased steadily and reached a maximum of +508 % for annual yield (+626% for a single cut) in the third year. This is by far the highest value of heterosis ever reported for annual dry mass yield of a forage grass. Conclusions: Further utilization of triploid hybrids in forage grass breeding is hampered by their sterility hence a need for vegetative propagation. However, artificial chromosome doubling of triploids to create fertile hexaploids, or seeking ways to propagate them vegetatively at an industrial scale might overcome this limitation.

scholarly journals Study of Chlorella vulgaris sedimentation process

2018 ◽  
Vol 240 ◽  
pp. 05023 ◽  
Author(s):  
Agnieszka Patyna ◽  
Małgorzata Płaczek ◽  
Stanisław Witczak
Keyword(s):  
Chlorella Vulgaris ◽  
Dry Mass ◽  
Separation Process ◽  
Cultivation Condition ◽  
Microalgal Biomass ◽  
Algae Biomass ◽  
Algae Cultivation ◽  
Sedimentation Process ◽  
Microalgae Harvesting

The paper reports the results of Chlorella vulgaris sedimentation process including description of cultivation condition of microalgal biomass. The process of algae cultivation was carried out in photobioreactor comprising systems of carbon dioxide supply, mixing and artificial LED illumination. The growth of microalgae was determined alternatively in three ways by measuring the amount of dry mass over time, counting the cells and measurement of optical density by use of a spectrophotometer. Algae biomass with different concentration was subjected to the separation process by gravity. This led to the determination of the characteristic of sedimentation process for different concentrations and cell sizes. The experimental results indicate that sedimentation process offers a tool with a potential application for microalgae harvesting.

scholarly journals Flooding Conceptual Review: Sustainability-Focalized Best Practices in Nigeria

2018 ◽  
Vol 8 (9) ◽  
pp. 1558 ◽  
Author(s):  
Giuseppe Cirella ◽  
Felix Iyalomhe
Keyword(s):  
Best Practices ◽  
Urban Areas ◽  
Ecosystem Stability ◽  
Indelible Mark ◽  
Economic Problems ◽  
The Third ◽  
Number Of Factors ◽  
The World ◽  
The Government ◽  
Environmentally Sound

Nigeria’s 196 million people is the third fastest growing population in the world; the interactions of this build up has left an indelible mark on the landscape and environment. Urbanization, deforestation, flooding, desertification, over population and all levels of pollution are resultant effects of this interaction with the environment. These changes directly relate to a seemingly endless desire for food, shelter, recreation and infrastructural facilities and urbanization in general. This has placed enormous pressure on ecosystem stability and environmentally sound living conditions. Flooding has become an annual event for Nigerian cities—where it consistently causes economic problems in the rainy season. Effort made by the government and residents to forestall this problem has produced sub-optimal results. There is a need to adopt more proactive, standard and reliable procedures that can offer sustainable outcomes and restore the socioeconomic growth of urban areas. Frequency of flooding is due to a number of factors relating to differing climatological patterns of precipitation, urban growth and increase in paved surfaces. The aim of this review is to utilize a conceptual framework to assess and identify areas within Nigeria prone to flooding and examine possible means of alleviating damage and harm.

scholarly journals Effects of Aluminum and pH on Germination of Echium plantagineum L.

2020 ◽  
Vol 8 (1) ◽  
pp. 313
Author(s):  
Rodrigo Roso ◽  
Ubirajara Russi Nunes ◽  
Caren Alessandra Müller ◽  
Juçara Terezinha Paranhos ◽  
Sidinei José Lopes ◽  
...  
Keyword(s):  
Aerial Part ◽  
Aluminum Sulfate ◽  
Growth Parameters ◽  
Primary Root ◽  
Dry Mass ◽  
The Third ◽  
Sulfate Solutions ◽  
Randomized Design ◽  
Primary Root Length ◽  
Growth Of Seedlings

The objetive of this study was to identify the effects of aluminum concentrations and pH levels of solution on germination of Echium plantagineum L. seeds. Three different experiments were carried out in completely randomized design with four repetitions. In the first experiment, we used aluminum sulfate solutions in concentrations of 0.0; 0.3; 0.6; 1.0; 2.0; 3.0; 4.0; 5.0; 6.0 and 7.0 cmolc L-1 and in the second experiment, solutions with different pH, 3.0; 4.0; 5.0; 6.0; 7.0; 8.0; 9.0 and 10.0. In the third experiment, we carried out a factorial (4x4) with aluminum sulfate solutions (0.0; 2.0; 4.0 and 6.0 cmolc L-1) and pH (4.0; 5.0; 6.0 and 7.0). It was evaluated the germination of Echium plantagineum L. at four and 14 days after seeding (DAS), germination speed index, primary root length, aerial part and dry mass of seedlings. The presence of aluminum reduced the germination by 27 and 40% at four and 14 DAS, respectively, in concentrations superior to 3.0 cmolc L-1. The three growth parameters presented linear reduction with the increase of aluminum concentrations. In the second experiment, the solutions with pH of 3.0 and 10.0 provided increases in germination, length of root and aerial part, and little influence in the dry mass of seedlings. In the third experiment, there was significant interaction between the aluminum concentrations and pH levels of substrate. The presence of aluminum in the substrate presented toxic effect on germination of seeds, length of seedlings and dry mass. The pH of the solution has little effect in germination of seeds and in the growth of seedlings of E. plantagineum.

scholarly journals Flaming to control weeds in seashore paspalum (Paspalum vaginatum Sw.) turfgrass

2019 ◽  
Author(s):  
Luisa Martelloni ◽  
Marco Fontanelli ◽  
Lisa Caturegli ◽  
Monica Gaetani ◽  
Nicola Grossi ◽  
...  
Keyword(s):  
Weed Control ◽  
Urban Areas ◽  
Optimal Dose ◽  
Liquefied Petroleum Gas ◽  
Seashore Paspalum ◽  
The Third ◽  
Paspalum Vaginatum ◽  
Weed Cover ◽  
The University ◽  
Flame Weeding

Weed control is crucial to ensure that turfgrass is established effectively. Although herbicides are commonly used to control weeds in turfgrasses, environmental and public health concerns have led to limiting or banning the use of synthetic herbicides in urban areas. The species seashore paspalum (Paspalum vaginatumSw.) is susceptible to such herbicides. Flame weeding could be an alternative to the use of synthetic herbicides for selective weed control in seashore paspalum. In this study, five different liquefied petroleum gas (LPG) doses of flaming (0, 61, 91, 157 and 237 kg ha-1) were tested in order to find the optimal dose, in terms of weed control and costs. The aim was to maintain a seashore paspalum (cultivar ‘Salam’) turf free of weeds during spring green-up, and at the same time avoid damaging the turfgrass. Using a self-propelled machine designed and built at the University of Pisa, flaming was applied three times when weeds started growing and the turfgrass started green-up. Our results highlight that an LPG dose of 157 kg ha-1was the most economic dose that led to a significant reduction in initial weed cover and density, enabling the turfgrass to recover three weeks after the third application.

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