Seasonal Changes in Gonad Index,Biochemical Composition and Heavy Metal Determination of Sea Urchin Paracentrotus lividus Gonads from the South Coast of Morocco

Ocean Science Journal - Seasonal variations of the gonad index (GI), the biochemical composition, and the concentration of heavy metals in the gonads of the sea urchin, Paracentrotus lividus...     

Role of Storm in Ramgarh and West Bokaro Coalfields and Its Implication in Adjacent Peninsular Gondwana Coalfields, India

The Permian Gondwana sediments in the Damodar-Koel Valley, Rajmahal and Deoghar basins were deposited on a northwest palaeoslope in broad valleys within uplands (e.g. Aravalli-Vindhyan, Chattisgarh, Chotanagpur and Santhal Parganas upland). The main winds during Permian Period were mostly the westerly winds coming from the northwest low pressure belt in the Tethys, which found no barrier between the Vindhyan and Santhal Parganas uplands and then changing its direction, moving towards east. Frequent storm activity also took place from the northwest Tethyan low pressure belt and followed the same path of wind. Possibly there was a barrier in the form of a dense rain forest or elevated land at the place of East Bokaro coalfield and its adjoining southern part, which acted as a deterrent and minimized the effect of storm towards further east of the Damodar Valley. Intense tropical hurricanes for the generation of storm generated bedforms, cannot be ruled out, which probably, in some cases, causes marine inundation/flooding deep into the landmass and also mass (?) uprooting of trees.     

Long-term changes and variability of monthly extreme temperatures in India

Extreme temperatures are changing worldwide together with changes in the mean temperatures. This study investigates the long-term trends and variations of the monthly maximum and minimum temperatures and their effects on seasonal fluctuations in various climatological regions in India. The magnitude of the trends and their statistical significance were determined by parametric ordinary least square regression techniques and the variations were determined by the respective coefficient of variations. The results showed that the monthly maximum temperature increased, though unevenly, over the last century. Minimum temperature changes were more variable than maximum temperature changes, both temporally and spatially, with results of lesser significance. The results of this study are good indicators of Indian climate variability and its changes over the last century.     

Monsoon rainfall extreme indices and tendencies from 1954–2003 in Kerala,India

Climate change has the potential ability to alter the occurrence and severity of extreme events. Though predicting changes of such extreme events is difficult, understanding them is important to determine the impacts of climate change in various sectors. This paper presents the change in rainfall extremes in the monsoon season in south-west Indian peninsula. Daily rainfall data were analysed for the entire Kerala state in India to determine if the extreme rainfall had changed over the 50-year period. Several indices were derived from the data to identify the extreme rainfalls. The trends of all the extreme indices were assessed by parametric ordinary least square regression technique, which were tested for significance at 95% level. Results showed significant decrease in monsoon rainfall extremes in Kerala that would affect the tendency of change in seasonal total rainfall. This study provides a comprehensive knowledge on extreme monsoon precipitation in Kerala, which could also be employed to study changing climate at local scale in other regions.     

New cynodont record from the lower Triassic Panchet Formation,Damodar valley

This paper reports the find of a new non-mammalian cynodont from the Lower Triassic Panchet Formation of the Damodar valley, West Bengal, India. The fossil, recovered from a clay pellet rich calcareous sandstone bed, is a part of left lower jaw having five post canines that are damaged to various extents. A combination of mammal-like advanced characters such as much enlarged dentary, reduced post dentary bones, high coronoid process, large masseteric fossa, each post canine with a large central cusp flanked by a distal and a mesial accessory cusps with two additional lingually positioned cingular cusps, incipient root division and clearly demarcated crown-root juncture prompted to erect a new taxon Panchetocynodon damodarensis gen. et sp. nov.     

Early Permian Palaeoenvironment in Damodar Valley Coalfields, India: an Overview

In the Damodar Valley Basin, coalfields containing coal bearing Barakar Formation are Raniganj, Jharia, Bokaro, Ramgarh, and Karanpura. The Barakar Formation is composed of conglomerate, sandstone, siltstone, shale, fireclay, and coal. The lower part of Barakar Formation represents a braided channel deposit, and also in few places glacio-fluvial deposit which changes to meandering channel system with the formation of some ox-bow lake, and cut-off channel in the middle part. In a few places deltaic/brackish water condition possibly existed along with this meandering channel system. In the upper part of Barakar Formation, marine signatures are more prominant. Marine signatures/influences have been reported from Barakar Formation of Ramgarh, South Karanpura, and West Bokaro coalfields on the basis of trace fossil assemblage, sedimentation character, and trace element content. Although, definite marine signatures have not been observed from Jharia, and Raniganj coalfields, high concentration of boron, vanadium, and chromium, and presence of skolithos, and thalassinoides burrows possibly suggest a brackish water condition. The upper part clearly suggest that the sediments were deposited in a geographic setting very close to the sea or at the edge of the sea possibly in a peritidal setting where storm activity played a vital role during sedimentation which in turn suggests the presence of a broad shallow sea (epeiric/epicontinental sea) that develop during times of high sea level. The sea water possibly entered from the northeastern side as vast seaways or as embayment through the Damodar Valley which acted as a channel.     

Quantifying regional groundwater flow between Continental Intercalaire and Djeffara aquifers in southern Tunisia using isotope methods

Large-scale interaction between the Continental Intercalaire and the Djeffara aquifer systems in the southeast of Tunisia has been investigated with the aid of chemical and isotopic tracers. Two distinct groundwater types have been identified: (1) the Continental Intercalaire groundwater characterized by elevated temperatures (50–61.4°C), low δ¹⁸O (−8.4 to−7.87) and δ²H (−67.2 to−59) values and negligible radiocarbon content, both testifying its great age dating from the late Pleistocene period, and (2) the Djeffara groundwater with distinctly heavier isotopic composition (δ¹⁸O = −8.31 to −5.80, δ²H = −65.9 to −31.9). The Djeffara groundwaters reveal a distinct changes of physico-chemical and isotopic parameters near El Hamma Faults in the northwestern part of the Djeffara basin. These changes could possibly be explained by a vertical leakage from the Continental Intercalaire aquifer through El Hamma Faults. The mixing proportions inferred from stable isotope mass balance prove that the contribution of the Continental Intercalaire to the recharge of Djeffara aquifer is very significant and may reach 100% in the El Hamma region and in the northern part of Gabes. Isotope tracers strongly suggest that recent recharge to the Djeffara aquifer system is very limited. Its current yield, particularly in its central and northern parts can be maintained only thanks to large-scale underground inflow from the Continental Intercalaire aquifer system, which carries late Pleistocene palaeowater. Consequently, current exploitation of groundwater resources of the Djeffara aquifer has non-sustainable character.     

Assessing seasonal precipitation trends in India using parametric and non-parametric statistical techniques

This paper provides an insight into the long-term trends of the four seasonal and annual precipitations in various climatological regions and sub-regions in India. The trends were useful to investigate whether Indian seasonal rainfall is changing in terms of magnitude or location-wise. Trends were assessed over the period of 1954?C2003 using parametric ordinary least square fits and non-parametric Mann?CKendall technique. The trend significance was tested at the 95% confidence level. Apart from the trends for individual climatological regions in India and the average for the whole of India, trends were also specifically determined for the possible smaller geographical areas in order to understand how different the trends would be from the bigger spatial scales. The smaller geographical regions consist of the whole southwestern continental state of Kerala. It was shown that there are decreasing trends in the spring and monsoon rainfall and increasing trends in the autumn and winter rainfalls. These changes are not always homogeneous over various regions, even in the very short scales implying a careful regional analysis would be necessary for drawing conclusions regarding agro-ecological or other local projects requiring change in rainfall information. Furthermore, the differences between the trend magnitudes and directions from the two different methods are significantly small and fall well within the significance limit for all the cases investigated in Indian regions (except where noted).     

印度旱灾和水灾的区域变化

The most important climatological feature of the South Asian region is the occurrence of monsoons.With increasing concerns about climate change,the need to understand the nature and variability of such climatic conditions and to evaluate possible future changes becomes increasingly important.This paper deals with long-term above and below normal monsoon precipitation causing prolong meteorological droughts and floods in India.Five regions across India comprising variable climates were selected for the study.Apart from long-term trends for individual regions,long-term trends were also calculated for the Indian region as a whole.The results show that intra-region variability for monsoon precipitation is large and there are increasing numbers of meteorological summer droughts.Meteorological monsoon floods were found to have negative long-term trends everywhere except in the peninsular Indian region.The results overall suggest generic conclusions concerning the region-wide long-term trend of severity of monsoon droughts and floods in India and their spatial variability.     

Impacts of the dumping site on the environment: Case of the Henchir El Yahoudia Site, Tunis, Tunisia

The Henchir El Yahoudia landfill is one among many uncontrolled dumping sites in Tunisia with no bottom liner. It is located at the southeastern edge of Sijoumi Sebkha. The site has been exploited since 1963 until 1994. It constitutes a peculiar case because of its situation, its exploitation mode and the nature of buried wastes. Leachate analysis shows that they are strongly charged with nitrogen (especially ammoniacal and kadjedahl), organic compounds with a high biodegradability and a charge of metallic elements exceeding the Tunisian norm NT 106-002. Sediment analyses show that the highest rate of heavy metals and organic matter coincides with clay-richest layers, characterized by the highest specific-surface values. The percolation of these pollutants until the groundwater between 0.5 and 5 m has provoked a pollution characterized by high rates of organic matter (BOD, COD and nitrogen) and heavy metals. To cite this article: A. Marzougui, A. Ben Mammou, C. R. Geoscience 338 (2006).