oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Archaeological Excavation Of Trangampadi (TRANQUEBAR) At Danish Fort
M. NILAVENDAN
Indian Streams Research Journal , 2012,
Abstract: The History of Tranquebar could be traced back to the beginning of theChristian Era. Ancient Sangam classics like the Purananooru, Natrinai andAgananooru refer to Poraiyar. The famous poet kalladanar praises the chieftain ofPoraiyar in Puram 391. Poraiyar is referred to as a port town is Munturai. It is likelythat the sea with was originally skirting Poraiyar has receded subsequent to the secondcentury A.D by about a mile. Poraiyar continued to play important role in the history ofTranquebar till 19th century.
Osmoderma eremita (Coleoptera, Scarabaeidae, Cetoniinae) in Europe
Ranius, T.,Aguado, L. O.,Antonsson, K.,Audisio, P.
Animal Biodiversity and Conservation , 2005,
Abstract: Research, monitoring and development of preservation strategies for threatened species are often limited by national borders even though a global perspective would be more appropriate. In this study, we collected data on the occurrence of a threatened beetle, Osmoderma eremita, associated with tree hollows in 2,142 localities from 33 countries in Europe where it is or has been present. The larvae develop in tree hollows and very few observations of larvae have been observed in dead logs on the ground. As long as there is a suitable tree hollow, it appears that O. eremita may use any tree species. Oaks (Quercus spp.) are the trees mainly used by O. eremita, followed by lime (Tilia spp.), willow (Salix spp.), beech (Fagus sylvatica)and fruit trees (Prunus spp., Pyrus spp., Malus domestica). O. eremita is still found in some remnants of natural forest, but is mainly observed on land that has long been used by man, such as pasture woodlands, hunting parks, avenues, city parks and trees around agricultural fields and along streams. The occurrence of O. eremita seems to have decreased in all European countries. Relatively high densities of O. eremita localities occur in Central Europe (northern Italy, Austria, Czechia, southern Poland and eastern Germany), some parts of Northern Europe (south-eastern Sweden, Latvia) and France. In some regions in north-western Europe, the species is extinct or may occur at some single sites (Norway, Danish mainland, The Netherlands, Belgium, north-eastern France). There are few data from south-eastern Europe. Many local extinctions of O. eremita are to be expected in the near future, especially in regions with recent habitat loss and fragmentation. O. eremita is useful as an indicator and umbrella species for the preservation of the entire invertebrate community associated with hollow trees in Europe. A preservation plan for O. eremita should include three aspects that are of general importance in nature conservation in Europe today: (1) preservation of remnants of natural forests with old, broad-leaved trees, (2) preservation and restoration of habitats related to traditional agricultural landscapes and (3) preservation of remaining 'islands' of nature in urban areas.
Nutrient richness of wood mould in tree hollows with the Scarabaeid beetle Osmoderma eremita  [PDF]
J?nsson, N.,Ranius, T.,Méndez, M.
Animal Biodiversity and Conservation , 2004,
Abstract: Trunk hollows with wood mould habour a rich invertebrate fauna with many threatened species, and it has been suggested that the beetle Osmoderma eremita (Coleoptera, Scarabaeoidea) is a keystone species in this community. We estimated the amount of nitrogen and phosphorus in wood mould and compared the coarse fraction which constitutes frass of O. eremita with the finer fraction of wood mould, and found that the nutrient richness was higher in frass. O. eremita larvae have a fermentation chamber that harbours nitrogen fixing bacteria. As the levels of absorbable nitrogen are a limiting factor in insect growth, an increase in nutrient richness is one of several possible explanations why the species richness of saproxylic beetles is higher in hollow oaks where O. eremita is present in relation to similar trees where the beetle is absent.
Distribución espacial y temporal de poliquetos (Polychaeta) bénticos de la plataforma continental de Tamaulipas, Golfo de México
Delgado-Blas,V. Hugo;
Revista de Biología Tropical , 2001,
Abstract: in three oceanographic cruises off southern tamaulipas (may, july and november, 1992), a total of 102 sediment samples were collected by autonomous diving at depths of 2.5 to 20.5 m, with a cylindrical 4 liter acrylic tube. the samples were sieved (aperture size 0.5 and 1.0 mm). in total, 88 species of polychaete annelids were determined (33 families); 15 species are first records for mexico and three for the gulf of mexico. the dominant species were paraprionospio pinnata, scoletoma verrilli, ceratocephale oculata, aricidea finitima, apoprionospio pygmaea, onuphis eremita oculata and prionospio cristata; p. pinnata was the most abundant (14.4% of the total). highest abundance and diversity of species was in may (63 species and 622 organisms), followed by july (48 species and 401 organism); november was lowest (47species and 217 organisms). most diversity and abundance were found in the sandy bottoms.
Genetic identification of benthic polychaetes in a biodiversity hotspot in the southeast Pacific
Canales-Aguirre,Cristian B; Rozbaczylo,Nicolás; Hernández,Cristián E;
Revista de biología marina y oceanografía , 2011, DOI: 10.4067/S0718-19572011000100014
Abstract: the aim of this study was to evaluate the utility of coi, of the mitochondrial dna, for the taxonomic determination of soft-bottom benthic polychaetes in the chiloé inner sea as a particularly important zone for polychaete fauna of the southeast pacific. the results show high genetic differentiation between morphological species of polychaetes (posterior probabilities upper 0.9), and onuphis pseudoiridescens showed the greatest divergence (3.08 ± 0.08 s.d.). the results support the role of the coi gene as a useful molecular marker for fast and accurate taxonomic determination of benthic polychaetes. this study leads the way for research on the biodiversity and systematics of polychaetes off the chilean coast using molecular phylogenetic criteria.
Distribución espacial y temporal de poliquetos (Polychaeta) bénticos de la plataforma continental de Tamaulipas, Golfo de México
V. Hugo Delgado-Blas
Revista de Biología Tropical , 2001,
Abstract: Durante tres campa as oceanográficas en el sur del litoral de Tamaulipas (mayo, julio y noviembre de 1992), se recolectaron 102 muestras de sedimentos mediante buceo autónomo a profundidades de 2.5 a 20.5 m, con un nucleador de acrílico de forma cilíndrica de 4 l, tamizándose con una abertura de luz de malla de 0.5 y 1.0 mm. Se determinaron 88 especies de poliquetos (33 familias); 15 especies se registran por primera vez para aguas mexicanas y tres para el Golfo de México. Las especies dominantes son Paraprionospio pinnata, Scoletoma verrilli, Ceratocephale oculata, Aricidea finitima, Apoprionospio pygmaea, Onuphis eremita oculata y Prionospio cristata; P. pinnata es la más abundante (14.4% del total). En mayo se presentó la mayor diversidad de especies y abundancia (63 spp y 622 org.); seguida de julio (48 spp y 401 org.); la menor fue noviembre (47 spp y 217 org.). Las mayores diversidad de especies y abundancia fueron en fondos arenosos. In three oceanographic cruises off southern Tamaulipas (May, July and November, 1992), a total of 102 sediment samples were collected by autonomous diving at depths of 2.5 to 20.5 m, with a cylindrical 4 liter acrylic tube. The samples were sieved (aperture size 0.5 and 1.0 mm). In total, 88 species of polychaete annelids were determined (33 families); 15 species are first records for Mexico and three for the Gulf of Mexico. The dominant species were Paraprionospio pinnata, Scoletoma verrilli, Ceratocephale oculata, Aricidea finitima, Apoprionospio pygmaea, Onuphis eremita oculata and Prionospio cristata; P. pinnata was the most abundant (14.4% of the total). Highest abundance and diversity of species was in May (63 species and 622 organisms), followed by July (48 species and 401 organism); November was lowest (47species and 217 organisms). Most diversity and abundance were found in the sandy bottoms.
Influences of petroleum on accumulation of copper and cadmium in the polychaete Nereis diversicolor
SUN Fu-hong,ZHOU Qi-xing,ZHANG Qian-ru,
SUN Fu-hong
,ZHOU Qi-xing,ZHANG Qian-ru

环境科学学报(英文版) , 2006,
Abstract: Using the exposure simulation experiment, the action of petroleum affecting the accumulation of the trace metals including copper (Cu) and cadmium (Cd) in littoral polychaete Nereis diversicolor collected from the Shuangtaizi Estuary in Liaoning Pr
Polychaete assemblage of an impacted estuary, Guanabara Bay, Rio de Janeiro, Brazil
Santi, Leonardo;Tavares, Marcos;
Brazilian Journal of Oceanography , 2009, DOI: 10.1590/S1679-87592009000400004
Abstract: thirty-eight stations were sampled in guanabara bay, rio de janeiro, brazil, to assess the spatio-temporal diversity and biomass of sublittoral polychaetes. samples were collected during the dry (september 2000) and rainy season (may 2001) in shallow sublittoral sediments. the polychaete spatial composition showed a heterogeneous distribution throughout the bay. a negative gradient of diversity and biomass was observed towards the inner parts of the bay and sheltered areas. a wide azoic area was found inside the bay. some high-biomass and low-diversity spots were found near a sewage-discharge point. in these areas, the polychaete biomass increased after the rainy season. a diversified polychaete community was identified around the bay mouth, with no dramatic changes of this pattern between the two sampling periods. deposit-feeders were dominant in the entire study area. the relative importance of carnivores and omnivores increased towards the outer sector, at stations with coarse sediment fractions. guanabara bay can be divided into three main zones with respect to environmental conditions and polychaete diversity and biomass patterns: a) high polychaete diversity, hydrodynamically exposed areas composed of sandy, oxidized or moderately reduced sediments with normoxic conditions in the water column. b) low diversity and high biomass of deposit and suspension-feeding polychaete species in the middle part of the bay near continental inflows, comprising stations sharing similar proportions of silt, clay and fine sands. c) azoic area or an impoverished polychaete community in hydrodynamically low-energy areas of silt and clay with extremely reduced sediments, high total organic matter content and hypoxic conditions in the water column, located essentially from the mid-bay towards the north sector. high total organic matter content and hypoxic conditions combined with slow water renewal in the inner bay seemed to play a key role in the polychaete diversity and biomass. s
Distribution of Polychaete Assemblage in Relation to Natural Environmental Variation and Anthropogenic Stress Distribution of Polychaete Assemblage in Relation to Natural Environmental Variation and Anthropogenic Stress  [PDF]
ZAN Xiaoxiao,ZHANG Chongliang,XU Binduo,XUE Ying,REN Yiping
- , 2015,
Abstract: Polychaete are diverse species of the soft-bottom community, and are often used as indicators in environment monitoring programs. However, the effects of anthropogenic activities and natural environmental variation on polychaete assemblage are rarely addressed. The goals of this study are to identify the effects of natural environmental variation and anthropogenic stress on polychaete assemblage, and to explore the relationship between the polychaete assemblage structure and anthropogenic stress without considering the natural environmental variation. Based on the data collected from the surveys conducted in the tidal flat of Jiaozhou Bay, the relationship between polychaete assemblage structure and environmental variables was determined using multivariate statistical methods including hierarchical cluster analysis, multidimensional scaling(MDS) and canonical correspondence analysis(CCA). The results showed that the polychaete assemblage was dominated by two species, Amphictene japonica and Heteromastus filiformis, and could be divided into two subgroups characterized by high and low species abundance. CCA illustrated that the natural environmental variables including water temperature and the distance from coast had primary effects on the polychaete assemblage structure; while stress of contaminants, such as As and Hg, had the secondary influences; and stress from the aquacultured species, mainly Ruditapes philippinarum, had a limited effect. Colinearity between the natural environmental variables and anthropogenic stress variables caused a critical divergence in the interpretation of CCA results, which highlighted the risk of a lack of information in environment assessment. Glycinde gurjanovae, Sternaspis scutata and Eulalia bilineata may serve as the ‘contamination indicators', which need to be confirmed in future studies
Superficial sediments and their relation to polychaete families in a subtropical embayment, Mexico
Méndez,Nuria; Green Ruiz,María;
Revista de Biología Tropical , 1998,
Abstract: the soft bottoms in front of mazatlan bay and "isla de la piedra" peninsula were studied to produce maps (depth, grain size and organic matter content in sediments). sixty samples were obtained with a 30 x 30 van veen grab (4-21 m depth) and polychaetewere extracted from 21 subsamples. grain size ranged from -1.05 phi (gravel) to 3.81 phi (very fine sand), with fine sand predominating. organic matter content in sediment was 0.91-3.06 % (most values = 1-2 %). thirty polychaete families (905 individuals/m2 in mean) were found, and cirratulidae, spionidae, onuphidae, and pilargiidae were dominant. pearson's correlation of grain size, organic matter and depth proved significant (p<0.01; p<0.02), confirming the observed relationships of distribution patterns in the area. a principal component analysis showed the association of several families to depth (factor 1), to grain size (factor 2), and to organic matter (factor 3). nevertheless, the distribution of polychaete families in the area may be governed by the combination of the three abiotic variables. results indicated that abiotic and biotic variables have not changed considerably since 1980
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.