scholarly journals Salinity and freshwater discharge determine rotifer distribution at the Mossoró River Estuary (Semiarid Region of Brazil)

2010 ◽  
Vol 70 (3) ◽  
pp. 551-557 ◽  
Author(s):  
AMA. Medeiros ◽  
JEL. Barbosa ◽  
PR. Medeiros ◽  
RM. Rocha ◽  
LF. Silva
Keyword(s):  
Species Richness ◽  
Rainy Season ◽  
Salinity Gradient ◽  
River Estuary ◽  
Positive Influence ◽  
Freshwater Discharge ◽  
The Other ◽  
Semiarid Region ◽  
Inverse Estuary ◽  
Species Richness And Abundance

The present study aimed at evaluating differences in rotifer distribution in three estuarine zones in an inverse estuary located in the Semiarid Region of Brazil. Zones were chosen based on their proximity to the ocean and river border as a means of reflecting a horizontal salinity gradient. High freshwater discharge during the rainy season was the major determinant of rotifer composition. On the other hand, due to higher salinity values during the dry season, very low values of species richness and abundance were observed in all zones. Therefore, the study highlights the constraints of salinity and the positive influence of seasonality and river proximity on rotifer species in a semiarid estuarine environment.

scholarly journals Patterns of species richness and abundance among cactus communities receiving different rainfall levels in the semiarid region of Brazil

2016 ◽  
Vol 30 (4) ◽  
pp. 569-576 ◽  
Author(s):  
Paulo Sérgio Monteiro Ferreira ◽  
Sérgio de Faria Lopes ◽  
Dilma Maria de Brito Melo Trovão
Keyword(s):  
Species Richness ◽  
Semiarid Region ◽  
Species Richness And Abundance

scholarly journals Diversity and distribution of testate amoebae (Amoebozoa, Rhizaria) in reservoirs, Northeastern Bulgaria

2018 ◽  
Vol 5 (2) ◽  
pp. 90-99
Author(s):  
Rositsa Davidova ◽  
Senay Sevginov
Keyword(s):  
Regression Analysis ◽  
Species Richness ◽  
Diversity Index ◽  
Taxonomic Diversity ◽  
Testate Amoebae ◽  
The Other ◽  
Water Volume ◽  
Species Richness And Abundance ◽  
Relationship Of ◽  
The Relationship

Abstract The aim of the study is to describe the testate amoebae fauna in seven reservoirs in the Northeastern Bulgaria and to investigate the relationship of taxonomic diversity and abundance of these organisms to the some characteristics of the reservoirs. A total of 52 species, varieties and forms belonging to 15 genera were identified in the benthal of the coastal zone. There are significant differences in species richness and abundance between the testacea of different reservoirs. Number of taxa was significantly higher in the Beli Lom (29 species and 12 genera) and Loznitsa (22 species and 13 genera). Most of the reservoirs - Kara Michal, Bogdantsi, Isperih, Lipnik and Brestovene have extremely poor fauna compared to other similar reservoirs. This is confirmed by the low values of the Shannon-Weaver diversity index, which varied between 1.04 and 2.396, as well as by the other indices used to assess the environmental conditions in the reservoirs. The data of the regression analysis showed that a relation between age, surface area and water volume of the reservoirs and the species richness and abundance of testacea is not established.

scholarly journals The spatial distribution of Hymenoptera parasitoids in a forest reserve in Central Amazonia, Manaus, AM, Brazil

2011 ◽  
Vol 71 (4) ◽  
pp. 865-871 ◽  
Author(s):  
RB. Querino ◽  
SRM. Couceiro ◽  
LO. Queiroz ◽  
AM. Penteado-Dias
Keyword(s):  
Spatial Distribution ◽  
Species Richness ◽  
Forest Canopy ◽  
Forest Ecosystems ◽  
The Other ◽  
Ecological Role ◽  
Forest Reserve ◽  
Central Amazonia ◽  
Dry Seasons ◽  
Species Richness And Abundance

Parasitoids are of great importance to forest ecosystems due to their ecological role in the regulation of the population of other insects. The species richness and abundance of parasitoids in the forest canopy and understory, both on the borders and in the interior of a tropical forest reserve in Central Amazonia were investigated. For a 12-month period, specimen collections were made every 15 days from suspended traps placed in the forest canopy and in the understory strata, both on the border and in the interior of forest areas. A total of 12,835 Hymenoptera parasitoids from 23 families were acquired. Braconidae, Diapriidae, Mymaridae, Eulophidae, and Scelionidae were the most represented in the area and strata samples. The results indicate that there were no significant differences in the species richness or abundance of Hymenoptera between the forest borders and the inner forest. The data does show that the presence of Hymenoptera is significantly greater in the understory in both the border and interior areas than in the canopy (vertical stratification). Aphelinidae and Ceraphronidae were significantly associated with the inner forest, while the other seven families with the border of the reserve. The abundance of Hymenoptera parasitoids presented seasonal variations during the year related to the rainy and dry seasons.

scholarly journals SEASONAL VARIATION OF NITROGEN CYCLING IN MANILA BAY

2018 ◽  
Vol 32 (2) ◽  
pp. 75-87
Author(s):  
Mitsuru Hayashi ◽  
Tetsuo Yanagi ◽  
Maria Lourdes San Diego-Mcglone
Keyword(s):  
Seasonal Variation ◽  
Solar Radiation ◽  
Nitrogen Cycling ◽  
Rainy Season ◽  
River Discharge ◽  
Lower Layer ◽  
River Estuary ◽  
Ecosystem Model ◽  
The Other ◽  
Manila Bay

Seasonal variation in nitrogen cycling at the upper layer of the Pasig River estuary in Manila Bay was calculated during January 1996 to December 1998 by using the numerical ecosystem model. Chl.a and DIN concentrations are relatively low, river discharge is small, and solar radiation is strong from March to May in dry season. The main reason of low chl.a concentration is that the solar radiation is too strong. On the other hand, as DIN concentration is relatively high and solar radiation is optimum, chl.a concentration is relatively high from August to December in rainy season. Main source of DIN in rainy season is the vertical transport from the lower layer due to the strong estuarine circulation.

scholarly journals Efeito do Envelhecimento de Isca na Captura de Moscas (Diptera: Brachycera) em Área de Caatinga

2014 ◽  
Vol 7 (1) ◽  
pp. 01-04 ◽  
Author(s):  
Eduardo Nascimento ◽  
Bianca Ambrogi ◽  
Leandro Sousa Souto ◽  
Marcelo Vilas-Bôas ◽  
Manoel Uchôa
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Exposure Time ◽  
Environmental Changes ◽  
Cane Sugar ◽  
The Other ◽  
Ecological Parameters ◽  
Significant Change ◽  
Species Richness And Abundance

Espécies de Diptera, principalmente as moscas, tem se mostrado como potenciais bioindicadores para mudanças ambientais. Para captura destes animais, há diferentes métodos, incluindo as armadilhas com atrativos alimentares. Neste estudo, para avaliar a eficiência de armadilhas na captura de moscas usando isca de melaço de cana-de-açúcar, foram avaliados os parâmetros ecológicos: abundância, riqueza e composição de espécies de moscas, comparando diferentes períodos de exposição das armadilhas em campo: 24, 48, 72 e 96h. A riqueza e abundância apresentaram mudança significativa em relação ao tempo de exposição da isca, tendo se estabilizado após 48h, e a composição diferiu entre o primeiro dia (24h) e os demais (48, 72, 96h). Effect of Aging Bait for Catching Flies (Diptera: Brachycera) in a Caatinga Area Abstract. Diptera species, especially flies, has shown potential as bioindicators for environmental changes. There are different methods to capture these animals, including traps with food baits. In this study, we assess the efficiency of traps for catching flies using bait of cane sugar molasses, analyzing the ecological parameters: abundance, species richness and species composition of flies during different periods of exposure of the traps in the field: 24, 48, 72 and 96h. Species richness and abundance showed significant change with respect to exposure time in the field, with stabilization after 48h, and species composition differed between the first and the other days.

E-Commerce Berbasis Marketplace Dalam Upaya Mempersingkat Distribusi Penjualan Hasil Pertanian

2017 ◽  
Vol 1 (2) ◽  
pp. 131-136 ◽  
Author(s):  
Deni Apriadi ◽  
Arie Yandi Saputra
Keyword(s):  
Agricultural Sector ◽  
Positive Influence ◽  
End Users ◽  
Marketing Channels ◽  
Agricultural Products ◽  
The Other ◽  
Media Campaign ◽  
Community Groups ◽  
Distribution Chain ◽  
Production Demand

The agricultural sector has an important role in supporting the Indonesian economy. But on the other hand, sometimes many community groups do not benefit due to problems that arise because the distribution chain of agricultural products are long enough, especially for farmers and consumers (end users). Of course the situation must be improved, so that the agricultural products of Indonesia can be enjoyed by consumers or farmers with proper. One of its efforts is by establishing an e-commerce based e-commerce system in agriculture. E-commerce based ecommerce system can be used as an alternative for farmers, used as a media campaign, communication and information and can cut the distribution chain of agricultural products marketing. The benefits felt by farmers and consumers directly and indirectly give a positive influence, especially from the broader marketing channels of agricultural products can increase production demand and spur the procurement of production among farmers and also the price offered to consumers will be cheaper so that sales in agricultural products can be more increased and profitable for farmers

scholarly journals Dispersal of persistent organic pollutants from fiber-contaminated sediments: biotic and abiotic pathways

2021 ◽  
Author(s):  
Anna-Karin Dahlberg ◽  
Anna Apler ◽  
Paul Frogner-Kockum ◽  
Gunnel Göransson ◽  
Ian Snowball ◽  
...  
Keyword(s):  
Organic Pollutants ◽  
Persistent Organic Pollutants ◽  
River Estuary ◽  
Contaminated Sediments ◽  
The Body ◽  
Passive Samplers ◽  
The Other ◽  
Sediment Surface ◽  
Average Particle ◽  
Particle Resuspension

Abstract Purpose Numerous sites contaminated with fiber emissions from pulp and paper industries are found in coastal areas of the Baltic Sea, but there is limited knowledge about the magnitude of dispersal of persistent organic pollutants (POPs) from these anthropogenic, organic-rich sediments called fiberbanks. The aim of this study was to quantify and compare different POP dispersal pathways from such fiberbanks. Dispersal mechanisms studied included abiotic and biotic routes (dissolved in water, particle-bound, and bioaccumulation). Materials and methods Contaminated fibrous sediments located in Ångermanälven River estuary in north-eastern Sweden were studied in sediment types representing different fiber content (i.e., fiberbanks, fiber-rich sediments, and less fiber impacted sediments). Sediment-to-water fluxes of dissolved contaminants (polychlorinated biphenyls (PCBs), hexachlorobenzene (HCB), and dichlorodiphenyltrichloroethane (DDT)) were measured in situ using benthic flux chambers. Particle resuspension was measured by sampling bottom water, before and after disturbing the sediment surface. Benthic biota was collected to determine the body burden of contaminants and to determine biota-pore water accumulation factors (BAFPW) and biota-sediment accumulation factors (BSAFs). In addition, concentrations of dissolved POPs in the water column were measured in field using passive samplers. Instrumental analysis was performed using gas chromatography coupled to a triple quadrupole mass spectrometer (GC-MS/MS). Results and discussion The flux of dissolved Σ20PCBs was approximately two times higher from one of the investigated fiberbanks (3.4 ng m− 2 day− 1) compared to the other. The average particle burden of PCBs was also higher at this fiberbank after artificial disturbance (15 ng g−1 particle), which indicates that larger amounts of contaminants are likely to disperse via particle resuspension from this site compared to the other fiberbank (4.8 ng g− 1 particle). The difference might be associated with a layer of recently settled minerogenic material that covers one of the fiberbanks, which probably functions as a protective barrier. The lack of benthic biota implies that contaminant release by bioturbation is negligible in the studied fiberbanks. However, benthic biota from fiber-rich sediment showed bioaccumulation and biomagnification of contaminants. Conclusions The importance of diffusive flux from fiberbanks under undisturbed conditions became apparent when the different dispersal pathways were quantified. However, no dispersal pathway could be judged as irrelevant, since even under undisturbed conditions, advective particle transport was significant. Additionally, the uptake by biota and trophic transfer can be considerable. Quantification of dispersal routes and understanding of the relative importance of various pathways is critical for proper risk assessment and management of contaminated sediments.

scholarly journals Impact of greenspaces in city on avian species richness and abundance in Northern Africa

2017 ◽  
Vol 340 (8) ◽  
pp. 394-400
Author(s):  
Hani Amir Aouissi ◽  
Julien Gasparini ◽  
Adnène Ibrahim Belabed ◽  
Zihad Bouslama
Keyword(s):  
Species Richness ◽  
Northern Africa ◽  
Avian Species ◽  
Species Richness And Abundance
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