scholarly journals The impact of the decomposition process of shallow graves on soil mite abundance

2021 ◽  
Author(s):  
Jas K. Rai ◽  
Brian J. Pickles ◽  
M. Alejandra Perotti
Keyword(s):  
Decomposition Process ◽  
Soil Mite ◽  
The Impact

scholarly journals Optimization of Decomposition Process of Karatau Phosphorites

2012 ◽  
Vol 14 (2) ◽  
pp. 183
Author(s):  
B. Myrzakhmetova ◽  
U. Besterekov ◽  
I. Petropavlovsky ◽  
S. Ahnazarova ◽  
V. Kiselev ◽  
...  
Keyword(s):  
Raw Materials ◽  
Phosphorous Acid ◽  
Regression Equation ◽  
Decomposition Process ◽  
Raw Material ◽  
Regression Equations ◽  
Phosphate Raw Material ◽  
Variance Estimate ◽  
The Impact ◽  
Temperature Time

Phosphorous-acid process of Karatau phosphorites’ decomposition has been studied. The impact of temperature, time and acid rate on decomposition process of phosphate raw material, the conditions ensuring maximum degree of phosphorite decomposition have been identified. Variance estimate of experiment results’ reproducibility has been carried out by mathematical statistics method; the coefficients of regression equations have been set. The significance of regression equation coefficients has been checked up by Student’s criterion, and the adequacy of regression equation to experiment has been checked up by Fisher's criterion. With the use of utopian point method the parameters of studied raw materials’ decomposition have been optimized.

scholarly journals Response of soil mite abundance and diversity to a monospecific timber Tectona grandis plantation in Ivory Coast

2013 ◽  
Vol 59 (5) ◽  
pp. 633-643 ◽  
Author(s):  
Julien Kouadio N’dri ◽  
Henri Marc Andre ◽  
Jan LagerlöF ◽  
Jérôme Ebagnérin Tondoh ◽  
Thierry Hance
Keyword(s):  
Ivory Coast ◽  
Soil Depth ◽  
Tectona Grandis ◽  
Primary Forest ◽  
Sampling Effort ◽  
Number Of Species ◽  
Teak Plantation ◽  
Soil Mite ◽  
Abundance And Diversity ◽  
The Impact

Abstract This study aims to assess the impact of monospecific Tectona grandis forest plantation on the soil mite abundance and diversity. To achieve these objectives, two sites situated in Ivory Coast were investigated. The first, a primary forest was characterized by a very weak human activities whereas the second, a teak plantation was characterized by a high disturbance performed during the planting. After extracting, sorted and description, 116 mite species were described in the two sites. Mite densities were lower in teak plantation and also higher in the litter and decreased to the depth in both sites. Species richness recorded in teak plantation (52 species) was significantly lower compared to primary forest (98 species). The same trend was observed for Oribatida but not for Gamasida. The lower Oribatida (5 vs. 17) and higher Oribatida (24 vs. 41) were recorded respectively in teak plantation and primary forest. Mite Shannon index and evenness were significantly different between sites. High Jaccard index values and the appearance of exclusive species in both habitats showed that the sites are very distinct. Total number of species recorded corresponded to 58%–63% of the total number of species estimated by ACE and Chao 1&2 estimators, indicating that the sampling effort was not sufficient. Mite abundance and diversity varied depending on the characteristics of habitats. Chemical element (Corg, Ctot, Ntot, and SOM) values were lower in teak plantation (disturbed habitat) and significantly different to primary forest in the topsoil. Apart from litter height, soil depth, pH and C/N ratio, others variables were strongly correlated to mite abundance and diversity.

Patterns of soil mite diversity in Lamto savannah (Côte d’Ivoire) submitted at different fire regimes

Acarologia ◽  
2017 ◽  
Vol 57 (4) ◽  
pp. 823-833
Author(s):  
Julien K. N'Dri ◽  
Rodolphe Arnaud G. N'Da ◽  
Fabrice A. Seka ◽  
Pacôme K. Pokou ◽  
Jérôme E. Tondoh ◽  
...  
Keyword(s):  
Cote D'ivoire ◽  
Côte D’Ivoire ◽  
Fire Regimes ◽  
Fire Intensity ◽  
Soil Cores ◽  
Cote D’Ivoire ◽  
Côte D'ivoire ◽  
Soil Mite ◽  
Abundance And Diversity ◽  
The Impact

In this study, we evaluated the impact of different fire regimes (early, mid-season, or late fire) on soil mite abundance and diversity in three study sites (Salty marigot, Plateau and North piste) of the Lamto shrub savannah at 160 km northwest of Abidjan, Côte d’Ivoire. On each site, three adjacent plots of 100 m x 50 m were delimited, to which a given fire regime was applied. At each site, soil cores were taken at 0-10 cm soil depth three days before the fire application, the day after and one month after the fire (10 soil cores x 3 sampling periods x 3 fire regimes or plots x 3 sites = 270 soil cores). Soil mites were then extracted from these cores. 108 soil cores were sampled at two upper layers (0-5 and 5-10 cm) for estimation of the bulk density and water content. After data analysis, four groups of mite were observed (Actinedida, Gamasida, Oribatida and Acaridida). Gamasida and Oribatida were dominant groups (early fire: Gamasida 35%, Oribatida 55%; mid-season fire: Gamasida 16%, Oribatida 70%; late fire: Gamasida 16%, Oribatida 74%). In total, 70 species were observed, with 29, 44 and 31 species recorded respectively during the early, mid-season and late fires. Mite density and species richness varied significantly along the three fire regimes and decreased substantially after fire application. Except for the mid-season fire, Simpson index from all mites differed significantly across sampling periods. Lower Oribatida represented 25% of the total Oribatida. Whatever the fire regimes, brachypyline Oribatida abundance increased the day after fire application. Overall, fire intensity reduced drastically soil mite abundance and diversity.

scholarly journals Consequences of removal of exotic species (eucalyptus) on carbon and nitrogen cycles in the soil-plant system in a secondary tropical Atlantic forest in Brazil with a dual-isotope approach

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9222
Author(s):  
Milena Carvalho Teixeira ◽  
Angela Pierre Vitória ◽  
Carlos Eduardo de Rezende ◽  
Marcelo Gomes de Almeida ◽  
Gabriela B. Nardoto
Keyword(s):  
Organic Matter ◽  
Exotic Species ◽  
Atlantic Forest ◽  
Secondary Forest ◽  
Organic Matter Decomposition ◽  
Decomposition Process ◽  
Dual Isotope ◽  
Carbon And Nitrogen ◽  
Plant System ◽  
The Impact

The impact of exotic species on heterogeneous native tropical forest requires the understanding on which temporal and spatial scales these processes take place. Functional tracers such as carbon (δ13C) and nitrogen (δ15N) isotopic composition in the soil-plant system might help track the alterations induced by the exotic species. Thus, we assess the effects from the removal of the exotic species eucalyptus (Corymbia cytriodora) in an Atlantic forest Reserve, and eucalyptus removal on the alteration of the nutrient dynamics (carbon and nitrogen). The hypotheses were: (1) the eucalyptus permanence time altered δ13C and δ15N in leaves, soils and litter fractions (leaves, wood, flowers + fruits, and rest); and (2) eucalyptus removal furthered decomposition process of the soil organic matter. Hence, we determined the soil granulometry, the δ13C and δ15N in leaves, in the superficial soil layer, and litter in three sites: a secondary forest in the Atlantic forest, and other two sites where eucalyptus had been removed in different times: 12 and 3 months ago (M12 and M3, respectively). Litter samples presented intermediate δ13C and δ15N values in comparison with leaves and soil. In the M3, the greater δ13C values in both litter rest fraction and soil indicate the presence, cycling and soil incorporation of C, coming from the C4 photosynthesis of grassy species (Poaceae). In the secondary forest, the soil δ15N values were twice higher, compared with the eucalyptus removal sites, revealing the negative influence from these exotic species upon the ecosystem N dynamics. In the M12, the leaves presented higher δ13C mean value and lower δ15N values, compared with those from the other sites. The difference of δ13C values in the litter fractions regarding the soil led to a greater fractioning of 13C in all sites, except the flower + fruit fractions in the secondary forest, and the rest fraction in the M3 site. We conclude that the permanence of this exotic species and the eucalyptus removal have altered the C and N isotopic and elemental compositions in the soil-plant system. Our results suggest there was organic matter decomposition in all litter fractions and in all sites. However, a greater organic matter decomposition process was observed in the M3 soil, possibly because of a more intense recent input of vegetal material, as well as the presence of grassy, easily-decomposing herbaceous species, only in this site. Therefore, the dual-isotope approach generated a more integrated picture of the impact on the ecosystem after removing eucalyptus in this secondary Atlantic forest, and could be regarded as an option for future eucalyptus removal studies.

Formation of Lunar Craters and Bright Rays as a Result of Meteorite Impacts

1962 ◽  
Vol 14 ◽  
pp. 415-418
Author(s):  
K. P. Stanyukovich ◽  
V. A. Bronshten
Keyword(s):  
Explosive Charge ◽  
The Moon ◽  
Meteorite Impacts ◽  
The Earth ◽  
Lunar Craters ◽  
The Impact

The phenomena accompanying the impact of large meteorites on the surface of the Moon or of the Earth can be examined on the basis of the theory of explosive phenomena if we assume that, instead of an exploding meteorite moving inside the rock, we have an explosive charge (equivalent in energy), situated at a certain distance under the surface.

The Geosciences Applied to Lunar Exploration

1962 ◽  
Vol 14 ◽  
pp. 169-257 ◽  
Author(s):  
J. Green
Keyword(s):  
Lunar Surface ◽  
Probable Mechanism ◽  
Point Of View ◽  
Lunar Exploration ◽  
Geological Model ◽  
Apply Geophysics ◽  
Surface Features ◽  
The Impact

The term geo-sciences has been used here to include the disciplines geology, geophysics and geochemistry. However, in order to apply geophysics and geochemistry effectively one must begin with a geological model. Therefore, the science of geology should be used as the basis for lunar exploration. From an astronomical point of view, a lunar terrain heavily impacted with meteors appears the more reasonable; although from a geological standpoint, volcanism seems the more probable mechanism. A surface liberally marked with volcanic features has been advocated by such geologists as Bülow, Dana, Suess, von Wolff, Shaler, Spurr, and Kuno. In this paper, both the impact and volcanic hypotheses are considered in the application of the geo-sciences to manned lunar exploration. However, more emphasis is placed on the volcanic, or more correctly the defluidization, hypothesis to account for lunar surface features.

Asteroid and Comet Impact Speeds upon Mars: Significance for Panspermia and the Supply of Organics

1997 ◽  
Vol 161 ◽  
pp. 197-201 ◽  
Author(s):  
Duncan Steel
Keyword(s):  
Probability Distributions ◽  
Regions Of Interest ◽  
Significant Fraction ◽  
Organic Chemicals ◽  
Impact Speed ◽  
The Mean ◽  
The Impact

AbstractWhilst lithopanspermia depends upon massive impacts occurring at a speed above some limit, the intact delivery of organic chemicals or other volatiles to a planet requires the impact speed to be below some other limit such that a significant fraction of that material escapes destruction. Thus the two opposite ends of the impact speed distributions are the regions of interest in the bioastronomical context, whereas much modelling work on impacts delivers, or makes use of, only the mean speed. Here the probability distributions of impact speeds upon Mars are calculated for (i) the orbital distribution of known asteroids; and (ii) the expected distribution of near-parabolic cometary orbits. It is found that cometary impacts are far more likely to eject rocks from Mars (over 99 percent of the cometary impacts are at speeds above 20 km/sec, but at most 5 percent of the asteroidal impacts); paradoxically, the objects impacting at speeds low enough to make organic/volatile survival possible (the asteroids) are those which are depleted in such species.

Organic Syntheses During the Impact of a Comet with a Gaseous Planet

1997 ◽  
Vol 161 ◽  
pp. 189-195
Author(s):  
Cesare Guaita ◽  
Roberto Crippa ◽  
Federico Manzini
Keyword(s):  
Polymeric Material ◽  
Molecular Form ◽  
Parent Compound ◽  
Blue Filter ◽  
Organic Syntheses ◽  
The Impact

AbstractA large amount of CO has been detected above many SL9/Jupiter impacts. This gas was never detected before the collision. So, in our opinion, CO was released from a parent compound during the collision. We identify this compound as POM (polyoxymethylene), a formaldehyde (HCHO) polymer that, when suddenly heated, reformes monomeric HCHO. At temperatures higher than 1200°K HCHO cannot exist in molecular form and the most probable result of its decomposition is the formation of CO. At lower temperatures, HCHO can react with NH3 and/or HCN to form high UV-absorbing polymeric material. In our opinion, this kind of material has also to be taken in to account to explain the complex evolution of some SL9 impacts that we observed in CCD images taken with a blue filter.

Hydrogen Cyanide Polymers from the Impact of Comet P/Shoemaker-Levy 9 on Jupiter

1997 ◽  
Vol 161 ◽  
pp. 179-187
Author(s):  
Clifford N. Matthews ◽  
Rose A. Pesce-Rodriguez ◽  
Shirley A. Liebman
Keyword(s):  
Amino Acids ◽  
Solar System ◽  
Hydrogen Cyanide ◽  
Nitrogen Heterocycles ◽  
Laboratory Studies ◽  
Heterogeneous Solids ◽  
The Many ◽  
Comet Halley ◽  
The Impact ◽  
By Products

AbstractHydrogen cyanide polymers – heterogeneous solids ranging in color from yellow to orange to brown to black – may be among the organic macromolecules most readily formed within the Solar System. The non-volatile black crust of comet Halley, for example, as well as the extensive orangebrown streaks in the atmosphere of Jupiter, might consist largely of such polymers synthesized from HCN formed by photolysis of methane and ammonia, the color observed depending on the concentration of HCN involved. Laboratory studies of these ubiquitous compounds point to the presence of polyamidine structures synthesized directly from hydrogen cyanide. These would be converted by water to polypeptides which can be further hydrolyzed to α-amino acids. Black polymers and multimers with conjugated ladder structures derived from HCN could also be formed and might well be the source of the many nitrogen heterocycles, adenine included, observed after pyrolysis. The dark brown color arising from the impacts of comet P/Shoemaker-Levy 9 on Jupiter might therefore be mainly caused by the presence of HCN polymers, whether originally present, deposited by the impactor or synthesized directly from HCN. Spectroscopic detection of these predicted macromolecules and their hydrolytic and pyrolytic by-products would strengthen significantly the hypothesis that cyanide polymerization is a preferred pathway for prebiotic and extraterrestrial chemistry.

Sign in / Sign up

Export Citation Format

Share Document