Weathering products of andesitic rocks from Sulawesi, Indonesia

Clay Minerals ◽  
1984 ◽  
Vol 19 (1) ◽  
pp. 21-28 ◽  
Author(s):  
H. W. Müller ◽  
G. Riedmüller ◽  
B. Schwaighofer
Keyword(s):  
Tropical Climate ◽  
Annual Rainfall ◽  
Valley Flank

AbstractMineralogical investigations of weathered andesitic bedrock and overburden on the valley flank of the Tondano river, Manado, Sulawesi, indicated that these had been subjected to different weathering conditions. The underlying andesite was completely altered to 7Å-halloysite and allophane. In the transported latosols of the overburden, 10Å- and 7Å-halloysites were found. The ratio of 10Å- to 7Å-halloysite increased linearly with depth in the profile. It is considered that weathering of the andesitic bedrock reflects a palaeoclimate with more strongly pronounced seasonal desiccation and lower annual rainfall. Neoformations by weathering of the overburden took place under the recent tropical climate.

Studies on the histerid beetle Pachylister chinensis in Fiji, and its possible value in the control of buffalo-fly in Australia

1968 ◽  
Vol 16 (4) ◽  
pp. 673 ◽  
Author(s):  
GF Bornemissza
Keyword(s):  
Density Distribution ◽  
Larval Development ◽  
Laboratory Tests ◽  
Tropical Climate ◽  
Dung Beetles ◽  
Breeding Habitat ◽  
Annual Rainfall ◽  
Pupal Period ◽  
Marked Preference ◽  
Searching Ability

P. chinensis, a predacious beetle that feeds on dipterous larvae breeding in dung of herbivores, was introduced from Java to Fiji in 1938 for the control of houseflies. The species is confined to areas having a wet tropical climate with a well-distributed annual rainfall exceeding 100 in. The beetle has a marked preference for cow pads in pastures with well-drained soils, and avoids areas shaded by trees. The female lays one or two eggs in the soil beneath a cow pad, and stays there from 2 to 3 days. P. chinensis larvae feed on active maggots as well as on fly puparia. Larval development occupies 16-20 days, and the pupal period some 30 days during the Fijian winter. In Fiji, P. chinensis has at least six generations per annum, and the adults live for more than a year. An abundance of prey ranging in length from 5 to 15 mm is essential for the survival of P. chinensis in Fiji, which attained a mean density ranging up to five beetles per cow pad in some localities. Laboratory tests at this density indicated that, due to the limited searching ability of the beetles and their larvae, only about 30-50 % of maggots in cow pads were destroyed. Because of its irregular density distribution and limited searching ability, no reliance should be placed on this predator for the control of the buffalo-fly in Australia. It is suggested that the efficiency of histerids in controlling flies could be enhanced by the introduction of dung beetles which would substantially reduce the breeding habitat of dipterous pests, thereby making them more vulnerable to predation. The evidence obtained during the course of this study did not suggest that P. chinensis influenced the abundance of houseflies in Fiji.

scholarly journals Relationship between Rainfall Pattern in North Central and Southern Nigeria and Some Tropical Climate Systems

2020 ◽  
pp. 74-88
Author(s):  
Esmond Gesever Ugbeji ◽  
Kingsley Chukwudi Okpala
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
North Atlantic ◽  
Central India ◽  
Tropical Climate ◽  
Sea Surface ◽  
Rainfall Pattern ◽  
Annual Rainfall ◽  
Temperature Index ◽  
Climate Systems

Monthly rainfall data from meteorological stations in Nigeria are analyzed from 1951 to 1992, to establish their relationship with some Tropical climate systems. The climate systems include Tropical South Atlantic (TSA) sea surface temperature index, North Atlantic Ocean (NAO) atmospheric index, Tropical North Atlantic (TNA) sea surface temperature index, Central India Precipitation (CIP) and and Outgoing Longwave Radiation Anomaly (OLRA)).  The rainfall pattern was given in terms of the August break (quantified in terms of the monsoon break intensity (MBI) and annual rainfall anomaly index (RAI). Partial correlation analysis was carried out to determine the effect of the tropical climate systems on the linear association between them and the stations in Nigeria. Our results show that the rainfall anomalies although sometimes intense do not have predictable patterns. The tele connection between CIP and total rainfall in Nigeria suggests that the rainfall patterns in Nigeria is likely to be modulated by the Tropical Easterly Jet (TEJ) connecting rainfall pattern in Central India to that in Nigeria. The August break is observed to be highly variable and does not show a clear discernable pattern of variability. Its variability may be connected with multiple forcings from ocean and mesoscale circulations.

THE ROLE OF GRASSLAND IN MANAGEMENT

1968 ◽  
pp. 44-49
Author(s):  
B.K. Cameron
Keyword(s):  
Soil Temperature ◽  
Annual Rainfall ◽  
Silt Loam ◽  
Average Annual Rainfall ◽  
Very High ◽  
Wilting Point

THE PROPERTY to be discussed is a mixed sheep and cropping unit, situated ei ht a miles east of Ashburton and midway between the Ra aia and the Ashburton rivers. Average annual rainfall is 27 in., evenly spread, but there is very high summer evaporation and therefore frequent droughts. On average, the soil is below wilting point for 40 to 50 days each summer. Winters are cold with the soil temperature being below 48°F for about four months each year. The soil is a Lismore stony silt loam averaging 9 in. in depth over gravel.

Water Budget of Constructed Wetland System with Subsurface Vertical Flow in Sub-Humid Tropical Climate

2015 ◽  
Vol 1 (5) ◽  
pp. 235-242
Author(s):  
Édio Damásio da Silva Júnior ◽  
Rogério de Araújo Almeida ◽  
Elisa Rodrigues Siqueira ◽  
Ábio Roduvalho da Silva
Keyword(s):  
Constructed Wetland ◽  
Water Budget ◽  
Tropical Climate ◽  
Vertical Flow ◽  
Humid Tropical Climate ◽  
Wetland System

Impact of changing rainfall conditions on surface and groundwater resources in an experimental watershed in Greece

2013 ◽  
Vol 12 (2) ◽  
pp. 119-125
Keyword(s):  
Groundwater Resources ◽  
Annual Runoff ◽  
Annual Rainfall ◽  
Rainfall Regime ◽  
Winter Rainfall ◽  
Rainfall Depth ◽  
Rainfall Volume ◽  
The Mean ◽  
Groundwater Reserves ◽  
The Impact

The present study concerns the impact of a change in the rainfall regime on surface and groundwater resources in an experimental watershed. The research is conducted in a gauged mountainous watershed (15.18 km2) that is located on the eastern side of Penteli Mountain, in the prefecture of Attica, Greece and the study period concerns the years from 2003 to 2008. The decrease in the annual rainfall depth during the last two hydrological years 2006-2007, 2007-2008 is 10% and 35%, respectively, in relation to the average of the previous years. In addition, the monthly distribution of rainfall is characterized by a distinct decrease in winter rainfall volume. The field measurements show that this change in rainfall conditions has a direct impact on the surface runoff of the watershed, as well as on the groundwater reserves. The mean annual runoff in the last two hydrological years has decreased by 56% and 75% in relation to the average of the previous years. Moreover, the groundwater level follows a declining trend and has dropped significantly in the last two years.

Trialing wetlands to treat coal mining wastewaters in a low rainfall, high evaporation environment

1997 ◽  
Vol 35 (5) ◽  
pp. 293-299 ◽  
Author(s):  
Wendy R. Tyrrell ◽  
David R. Mulligan ◽  
Lindsay I. Sly ◽  
L. Clive Bell
Keyword(s):  
Sulfate Reduction ◽  
Coal Mining ◽  
Pilot Scale ◽  
Cattle Manure ◽  
Annual Rainfall ◽  
Sulfate Reducing ◽  
Black Precipitate ◽  
Final Treatment ◽  
Reducing Bacteria ◽  
Initial Results

The large number of wetlands treating mining wastewaters around the world have mostly been constructed in temperate environments. Wetlands have yet to be proven in low rainfall, high evaporation environments and such conditions are common in many parts of Australia. BHP Australia Coal is researching whether wetlands have potential in central Queensland to treat coal mining wastewaters. In this region, mean annual rainfall is < 650 mm and evaporation > 2 000 mm. A pilot-scale wetland system has been constructed at an open-cut coal mine. The system comprises six treatment cells, each 125 m long and 10 m wide. The system is described in the paper and some initial results presented. Results over the first fourteen months of operation have shown that although pH has not increased enough to enable reuse or release of the water, sulfate reduction has been observed in parts of the system, as shown by the characteristic black precipitate and smell of hydrogen sulfide emanating from the wetlands. These encouraging signs have led to experiments aimed at identifying the factors limiting sulfate reduction. The first experiment, described herein, included four treatments where straw was overlain by soil and the water level varied, being either at the top of the straw, at the top of the soil, or about 5 cm above the soil. The effect of inoculating with sulfate-reducing bacteria was investigated. Two controls were included, one covered and one open, to enable the effect of evaporation to be determined. The final treatment consisted of combined straw/cattle manure overlain with soil. Results showed that sulfate reduction did occur, as demonstrated by pH increases and lowering of sulfate levels. Mean pH of the water was significantly higher after 19 days; in the controls, pH was < 3.3, whereas in the treatments, pH ranged from 5.4 to 6.7. The best improvement in sulfate levels occurred in the straw/cattle manure treatment.

AMEBAS PATÓGENAS DE VIDA LIBRE DEL GÉNERO ACANTHAMOEBA EN AGUAS RECREATIVAS EN LA HUASTECA POTOSINA, MÉXICO

2014 ◽  
Vol 7 ◽  
Author(s):  
Ricardo Ortiz Ortega ◽  
Alonso Vilches Flores ◽  
Marco Aurelio Rodríguez Monroy ◽  
Patricia Bonilla Lemus
Keyword(s):  
High Temperature ◽  
Water Body ◽  
Tropical Climate ◽  
Dry Season ◽  
Thermal Waters ◽  
Free Living ◽  
Severe Infections ◽  
Amebic Encephalitis ◽  
Animal Tests

Studies accomplished in freshwater demonstrate the importance of identify the presence of<br />protozoa like free living amoebae (FLA). In particular, the genera Acanthamoeba is associated with<br />severe infections in man, as the Granulomatous Amebic Encephalitis (GAE). The most important<br />factor for the development of these organisms is the high temperature of the water body. The<br />region of the Huasteca Potosina in Mexico, with a tropical climate and great aquatic resorts, like<br />rivers, waterfalls and pools of thermal waters, that allows the development of amoebae. In this<br />study we evaluated the presence of amoebas in the most visited places on the Huasteca Potosina.<br />Samples of a liter were taken in nine sites during the rainy and dry season. 54 strains of amoebas<br />were identify, 46 belong to the genera Acanthamoeba, resulting 30 of them pathogenic in the<br />animal tests. The pathogenic isolated amoebas were present in the most attended resorts by the<br />people in the waterfalls or pools of the places sampling. Temperature turned out to be the most<br />important factor for the presence of amoebae.

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