scholarly journals The impact of anthropogenic activities on the physicochemical characteristics of Cheleleka peat, Ethiopia

2021 ◽  
Vol 8 (3) ◽  
pp. 2751-2758
Author(s):  
Haymanot Tesfaye ◽  
Bikila Warkineh

Cheleleka peatland is located at the eastern side of Lake Hawassa and its biological communities face a variety of anthropogenic factors such as agricultural expansion, water diversion, settlement and subsequent peatland drainage and peat extraction. The decomposing products were influenced by various anthropogenic activities. This study aims to identify the impact of human activities on peat characteristics. The result indicates that the peat soil is acidic having a pH value ranging from 4.1-to-4.7 and containing humic acid due to excessive accumulation of organic matter and nutrients. The maturity level of the peat was almost similar in all study sites, except for the Daka site, and are classified under mostly decomposed. At Wesha, Werka, Wendo, Shalo, Cheffe, and Wendo, sites the maturity of the peat was classified under sapric soil. Exceptionally, at Daka Site, the peat maturity level was hemic. The percentage of sand, clay, and silt of the peatland range 40-50% clay, 30-40% silt and 10-20% sandy. The mean organic carbon content of Cheleleka peatland ranged from 4.48 to 38.65% and positively correlated with the thickness of the peat and negatively correlated with the ash content of the peat. The main effects of unsustainable landuse practice on peatland are peat reduction/complete loss, reduce water and nutrient retention capacity due to drainage and compaction of peat due to overgrazing. Changes in drainage, vegetation cover, and extraction of peat had resulted in differing outcomes from decomposition processes, and the properties of peats on the disturbed sites had changed.

Author(s):  
Ines Khedhri ◽  
Hanem Djabou ◽  
Ahmed Afli

The lagoon of Boughrara is the largest lagoon in Tunisia. For several decades it has been subject to the impact of increasing anthropogenic activities, and also to environmental stressors due to climate change and the low renewal of its waters. The present work is a contribution to the study of the functional organization of the benthic macrofauna of the lagoon of Boughrara 3 years after the extension of the channel ‘El Kantra’ which connects this lagoon to the open sea. In total, 13 stations facing the main prospective sources of disturbance and in areas likely to be more polluted were seasonally sampled during 2009–2010. Seasonal monitoring of the abiotic parameters shows a spatial heterogeneity linked to environmental and anthropogenic factors, including hydrodynamics, sedimentary texture and anthropogenic activities. The community of benthic macrofauna is generally poorly diversified at lagoonal-marine stations undergoing influences of both the marine and lagoon environment. The extreme seasons in terms of temperature and salinity seem to have an important role in the reduction of biodiversity in the lagoon of Boughrara. The trophic structure of the macrobenthic community is generally dominated by selective deposit feeders, and seems to be linked more to the availability of trophic resources than to disturbance.


Author(s):  
Joinal Abedin ◽  
Adrian Unc

The agricultural soils of the Happy Valley-Goose Bay (HV-GB) region of Newfoundland and Labrador, Canada are Podzols that are converted from boreal forest and have limited productivity due to their sandy texture, acidity, low soil organic matter (SOM), CEC, and water and nutrient retention capacity. While numerous studies advocate biochar for mitigating soil quality problems and enhancing agronomic productivity, there is limited information on managing biochar for boosting productivity of Podzols under newly converted agricultural lands. A 5-year experiment evaluated the impact of eight biochar rates (0 to 80 Mg C ha-1) on soil properties including SOM, CEC, and availability of plant nutrients and metals in agricultural soils of HV-GB. Both immediate and long term impacts were thus assessed. Biochar generally improved soil fertility indicators. While the largest rates (40 and 80 Mg C ha-1) led to the greatest changes, significant changes were also found with rates as low as 10 Mg C ha-1. Increasing biochar rates had diminishing returns for soil’s quality parameters. The impact of biochar decreased with time after application, but the largest rate led to longer lasting effects. Although biochar was incorporated in topsoil, its effects were also measurable in the subsoil, albeit with a temporal delay, usually of one year. Thus, given the diminishing returns of increasing biochar rates, and that beneficial effects diminish over years, it is advisable that biochar be added in smaller amounts immediately after conversion, as little as 10 Mg C ha-1, with regular supplementation as needed.


BioResources ◽  
2020 ◽  
Vol 15 (1) ◽  
pp. 1463-1481
Author(s):  
Defu Liu ◽  
Zhenyue Feng ◽  
Hongde Zhu ◽  
Lihe Yu ◽  
Kejun Yang ◽  
...  

Pot experiments were conducted to investigate the impact of biochar loading level on soybean growth and physico-chemical properties of alkaline soil. Biochar derived from corn straw was mixed with alkaline soil at 0%, 2.5%, 5%, and 10% loading levels and exposed to the natural elements. Soybean was used as the test crop. The results indicated that a single application of biochar positively and significantly improved soybean productivity and quality attributes of the tested alkaline soil. Soybean yield peaked at 5% loading level, but it declined at 10% loading. Applications of biochar at 5% and 10% loading significantly increased total soil porosity by 4.14% and 5.09%, and decreased the soil pH value by 0.07 and 0.24 units, respectively. Biochar addition significantly increased water holding capacity, total organic carbon content, total nitrogen, Olsen-P, available potassium, and cation exchange capacity. The results indicated that applications of corn straw biochar to alkaline soil improved soybean growth and promoted the physico-chemical properties of alkaline soil. However, the negative effects of increased C:N ratios and soil exchange sodium percentages at higher biochar loading levels should be taken into account when applying biochar as amendments to alkaline soils.


2021 ◽  
Author(s):  
Syrus Cesar Decena ◽  
Sarah Villacorta-Parilla ◽  
Arwin Arribado ◽  
Dionesio Macasait ◽  
Michael Arguelles ◽  
...  

Abstract Peatlands are unique wetland ecosystems that provide various ecosystem services such as carbon storage and biogeochemical cycling, however being threatened by anthropogenic activities. The present study was conducted to explore the impact of land use conversion on carbon stocks and peat properties in a tropical peatland in the Leyte Sab-a Basin Peatland (LSBP) in Northeastern Leyte, Philippines. The carbon stocks (aboveground and belowground) and physico-chemical properties of peat soil were compared among wetland forest, grassland and cropland. Land use conversion resulted in the significant reduction of the total aboveground carbon stock. The wetland forest had the highest carbon stocks (38.56 ± 4.58 t ha− 1), and when converted to grassland and cropland, it has resulted to carbon loss of as much as 86.59 and 90.45%, respectively. The belowground root carbon stock was highest in the wetland forest (5.05 ± 0.64 t ha− 1) also while highest peat carbon stock (1 m depth) was observed in the cropland areas (45.28 ± 2.25–61.27 ± 3.07 t ha− 1). However, wetland forests with very deep peat deposits potentially store a significant amount of carbon than in cropland that was characterized by shallower compressed peats. In addition, land use conversion altered the physico-chemical properties of peat such as water content, organic matter, and porosity, and bulk density which all indicated peatland degradation. Finally, the overall result of this study highlights the importance to develop and implement management and conservation plans for LSBP.


Author(s):  
Sophia Vauclin ◽  
Brice Mourier ◽  
André-Marie Dendievel ◽  
Nicolas Noclin ◽  
Hervé Piégay ◽  
...  

<p>In the context of increasing anthropic pressures on river systems, including river regulations, land-use changes, and widespread contamination, sediment deposits can act as critical archives of the hydro-sedimentary processes and of the impact of such pressures on river corridors. Depositional environments and their degree of connectivity with the main channel may, however, influence the nature, chronology, and continuity of sedimentary records. This point is highlighted through a case study in a reach of the Rhône River (Péage-de-Roussillon, France) subjected to strong anthropogenic pressures (river training, by-passing hydropower production, contamination). Sediment cores were retrieved from four distinct depositional environments with different levels of connectivity with the main channel: a floodplain, a semi-active secondary channel, a fully connected secondary channel and a small impoundment. A multi-proxy characterization of the cores was conducted, including grain-size, total organic carbon content, historical and emerging contaminants (metallic elements, various organic pollutants such as polychlorinated biphenyls and brominated flames retardants, etc.), and dating techniques. The analysis of these parameters shows that each environment recorded a different time period comprised between the 19<sup>th</sup> century and nowadays and associated with distinct markers of anthropogenic activities: the less the environment is connected, the older the record is. By combining the different cores, successive contamination trends can be reconstructed over time. In particular, a shift from polychlorinated biphenyls (PCBs) to polybrominated diphenyl ethers (PBDEs) as the predominant contaminant can be observed in the 1970s-1980s; such contamination sequence has hardly ever been documented in the literature. The diversity of depositional environments also allows identifying two types of infrastructure-induced legacy sediments deriving from two distinct periods of river engineering in the area. Overall, this work illustrates the spatial variability of sediment records in fluvial environments and the importance of retrieving multiple cores in diversified depositional environments to obtain an accurate and comprehensive archive of river contamination and functioning.</p>


2018 ◽  
Vol 16 (2) ◽  
pp. 237-243
Author(s):  
HM Solayman ◽  
Md Abdul Baten ◽  
Md Badiuzzaman Khan

Tanguar haor wetland is one of the listed Ramsar sites enrich with biodiversity variety and provides several ecosystem services with significant contribution to the national economy of Bangladesh. But these services were decreasing day by day due to natural and anthropogenic activities. The purposes of this study were to identify the utilized ecosystem services by communities, economic values of utilized ecosystem services and the basic reasons for depleting of ecosystem services. Data were collected through baseline survey, checklists, face to face questionnaire survey and focus group discussion (FGD) from 120 residential respondents and 50 tourist respondents by accepting random sampling techniques during November, 2016 to September, 2017. Physiochemical characteristics of the water were determined where the mean temperature and pH were 28.26°C and 7.72 respectively. The highest TDS, EC, DO, NO3 and PO4 values were 1020 (mg L−1), 1460 (μS cm−1), 8.56 (mg L−1), 1.769 (mg L−1) and 0.078 (mg L−1), respectively. Commonly utilized ecosystem services were crops, vegetables, fuel, fresh water, fishes and migratory birds, climate regulation, water purification, natural hazards protection, aesthetic, social relations, recreation & tourism, health benefit, primary production, nutrient cycling, water cycling habitats for species and provision of habitat etc. Market Value Method (MVM) and Contingent Value Method (CVM) were applied to measure the economic value of Tanguar haor wetland services. DPSIR framework and Impact Matrix (IM) were applied for conceptual analysis to identify the effects on ecosystem services. Total economic value of 39 ecosystem services of Tanguar haor was estimated at 174039980 BDT year−1. Mismanagement of biodiversity, over exploitation, sedimentation of haor, climate change, illegal hunting, land use changes and habitat changes were the responsible factors for depleting ecosystem services. The impact factor (4.161) was identified by natural and anthropogenic factors on ecosystem services. There have a vast prospect of the Tanguar haor wetland services for near communities. Finally the research suggested several sustainable management approaches which have the potentiality to protect the services of the wetland.J. Bangladesh Agril. Univ. 16(2): 237-243, August 2018


2021 ◽  
Vol 13 (4) ◽  
pp. 2089
Author(s):  
Dumitru Mihăilă ◽  
Petruț-Ionel Bistricean ◽  
Vasilică-Dănuț Horodnic

Currently, there is little information regarding the recent spatiotemporal dynamics of upper timberline in the Carpathian Mountains. We reconstructed the temporal (1887–2018) and spatial dynamics of upper timberline in the Rodna Mountains (Eastern Carpathians) based on seven sets of maps and aerial photographs and explained its variability in relation to three main drivers: air temperature, land morphometry and anthropogenic pressure. The impact of natural drivers (temperature, morphometry) on timberline position was evaluated using a high-resolution digital elevation model, local and regional instrumental and modelled climate databases. The impact of anthropogenic factors on timberline position was documented from published sources such as local paleolimnological studies and historical documents. Results show that timberline rose on average with 113 ± 2 m on the northern slope of the Rodna Mts (currently reaching 1640 m above sea level (a.s.l.)) and with 182 ± 2 m on the southern slope (up to an elevation of 1539 m a.s.l.). Our results suggest that this pattern might be connected with the rising temperature over the recent decades. On the northern slope where land morphometry restricts anthropogenic activities, timberline reached the highest elevation. On the more accessible southern slope, anthropogenic land-use changes likely moderated timberline elevational rise under increasing temperatures.


2021 ◽  
Vol 14 (3) ◽  
pp. 050-061
Author(s):  
Tra Bi Tra Jeannot ◽  
Kouassi Kouadio Henri

The present study concerns the diversity of the woody tree flora of Mont Sangbé National Park (West of Côte d'Ivoire). The main objective was to analyze the diversity of the woody tree flora of this park impacted by human activities. Specifically, it involved (1) identifying the anthropogenic factors of the PNMS, sources of impact (2) assessing the impact of these activities on the diversity of the woody tree flora of the PNMS and (3) propose measures to mitigate biodiversity losses. To carry out the study, a device of 14 square blocks of 1 ha each was used on the impacted sites and the control sites in the different biotopes of the park. Each block was subdivided into 100 square plots of 100m² each. The results show that anthropogenic activities have reduced the flora richness of the park, modified its floristic composition and caused the disappearance of some status species. It was proposed as a measure to step up surveillance of the park.


2015 ◽  
Vol 26 (3-4) ◽  
pp. 116-123
Author(s):  
A. P. Korzh ◽  
T. V. Zahovalko

Recently, the number of published works devoted to the processes of synanthropization of fauna, is growing like an avalanche, which indicates the extreme urgency of this theme. In our view, the process of forming devices to coexist with human and the results of his life reflects the general tandency of the modern nature evolution. Urbanization is characteristic for such a specific group of animals like amphibians, the evidence of which are numerous literature data. Many researchers use this group to assess the bioindicative quality of the environment. For this aim a variety of indicators are used: from the cellular level of life of organization up to the species composition of the group in different territories. At the same time, the interpretation of the results is not always comparable for different areas and often have significantly different interpretations by experts. Urban environment, primarily due to the contamination is extremely aggressive to amphibians. As a consequence, the urban populations of amphibians may be a change in the demographic structure, affecting the reproductive ability of the population, the disappearance of the most sensitive species or individuals, resizing animals, the appearance of abnormalities in the development, etc. At the same time play an important amphibians in the ecosystems of cities, and some species in these conditions even feel relatively comfortable. Therefore, it is interesting to understand the mechanisms of self-sustaining populations of amphibians in urban environments. To assess the impact of natural and anthropogenic factors on the development of amphibian populations were used cognitive modeling using the program Vensim PLE. Cognitive map of the model for urban and suburban habitat conditions were the same. The differences concerned the strength of connections between individual factors (migration, fertility, pollution) and their orientation. In general, factors like pollution, parasites, predators had negative impact on the population, reducing its number. The birth rate, food and migration contributed to raising number of individuals. Some of the factors affected on the strength to of each other as well: the majority of the factors affected the structure of the population, had an influence on the fertility. Thanks to it the model reflects the additive effect of complex of factors on the subsequent status of the population. Proposed and analyzed four scenarios differing strength and duration of exposure. In the first scenario, a one-time contamination occurs and not subsequently repeated. The second and third scenario assumes half board contamination, 1 year (2 scenario) and two years (scenario 3). In the fourth scenario, the pollution affected the population of amphibians constantly. In accordance with the results of simulation, much weaker than the natural populations respond to pollution - have them as an intensive population growth and its disappearance at constant pollution is slow. Changes to other parameters of the model showed that this pollution is the decisive factor -only the constant action leads to a lethal outcome for the populations. All other components of the model have a corrective effect on the population dynamics, without changing its underlying trand. In urban areas due to the heavy impact of pollution maintaining the population is only possible thanks to the migration process – the constant replenishment of diminishing micropopulations of natural reserves. This confirms the assumption that the form of existence metapopulations lake frog in the city. In order to maintain the number of amphibians in urban areas at a high level it is necessary to maintain existing migration routes and the creation of new ones. Insular nature of the placement of suitable habitats in urban areas causes the metapopulation structure of the types of urbanists. Therefore, the process of urbanization is much easier for those species whicht are capable of migration in conditions of city. In the initial stages of settling the city micropopulationis formed by selective mortality of the most susceptible individuals to adverse effects. In future, maintaining the categories of individuals is provided mainly due to migration processes metapopulisation form of the species of existence is supported). It should be noted that the changes in the previous levels are always saved in future. In the case of reorganizations of individuals we of morphology can assume the existence of extremely adverse environmental conditions that threaten the extinction of the micropopulations. 


Author(s):  
I. Saakian ◽  
Aleksandr, Grigor’ev ◽  
E. Kravets ◽  
E. Rudakov ◽  
A. Faddeev ◽  
...  

Выполнен анализ действующей редакции Методики разработки нормативов допустимых сбросов веществ и микроорганизмов в водные объекты для водопользователей , утвержденной приказом Минприроды России от 17 декабря 2007 г. 333, на предмет непротиворечивости и соответствия нормам водоохранного законодательства. Выявлена неопределенность применения Методики в условиях воздействия на качество воды природных и антропогенных факторов, не зависящих от конкретного водопользователя. Положения Методики противоречат принципам нормирования воздействия на водные объекты на основе наилучших доступных технологий, что было показано на примерах утвержденных технологических показателей содержания загрязняющих веществ в сточных водах различных отраслей промышленности. Анализ системы нормирования допустимых воздействий на водные объекты и географической дифференциации нормативов качества воды в пределах Российской Федерации вместе с системой целевых показателей качества воды также показал несоответствие Методики основным принципам водоохранного законодательства.The analysis of the current edition of the Methods of developing standards for permissible discharges of substances and microorganisms into water bodies for water users , approved by the Order of the Ministry of Natural Resources of Russia dated December 17, 2007 No. 333 for consilience and compliance with the regulations of the water protection legislation, is carried out. Uncertainty of the application of the Methods in the conditions of the impact of natural and anthropogenic factors that are independent of a specific water user on the quality of water has been identified. The provisions of the Methods contradict the principles of regulating the impact on water bodies based on the best available technologies shown on the examples of approved process indicators of the concentrations of various industrial pollutants in wastewater. An analysis of the system of regulating the permissible impact on water bodies and the geographical differentiation of water quality standards within the boundaries of the Russian Federation, together with the system of water quality targets, also showed that the Methods do not comply with the basic principles of the water protection legislation.


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