scholarly journals APLICAÇÃO DE UM PROTOCOLO DE AVALIAÇÃO AMBIENTAL RÁPIDA EM DOIS RESERVATÓRIOS DO SEMIÁRIDO BRASILEIRO

2016 ◽  
Vol 20 (1) ◽  
Author(s):  
MAIARA TÁBATHA DA SILVA BRITO ◽  
SILVANO LIMA DO NASCIMENTO FILHO ◽  
GIRLENE FÁBIA SEGUNDO VIANA ◽  
MAURO MELO JÚNIOR
Keyword(s):  
Arid Region ◽  
Riparian Vegetation ◽  
Environmental Changes ◽  
Rapid Assessment ◽  
Water Volume ◽  
Monitoring Tool ◽  
Assessment Protocol ◽  
Semi Arid Region ◽  
Artificial Reservoirs ◽  
Semi Arid

In the semi-arid region of Brazil, artificial reservoirs are ecosystems of extremely important ecological and social. Due to pressures caused by long periods of pluviometric irregularity, the reservoirs Cachoeira I and Barra, located in the interior of Pernambuco, have been subject to very significant changes, marked mainly by the reduction of stored water volume, seasonal changes in the abiotic parameters, reduction of riparian vegetation and absence of macrophytes. All these changes were observed in this study through the use of an auxiliary monitoring tool, a rapid assessment protocol adapted for lentic ecosystems of semiarid, capable of detecting numerous types of environmental changes, assisting in monitoring these springs.

scholarly journals Effectiveness of abundance and biomass curves in detecting environmental alterations in semi-arid region reservoirs

2018 ◽  
Vol 18 (2) ◽  
Author(s):  
Carlinda Raílly Medeiros ◽  
Evaldo de Lira Azevêdo ◽  
José Etham de Lucena Barbosa ◽  
Joseline Molozzi
Keyword(s):  
Arid Region ◽  
Water Resource Management ◽  
Environmental Indicators ◽  
Water Volume ◽  
Severe Drought ◽  
Drought Period ◽  
Littoral Region ◽  
Semi Arid Region ◽  
Effective Diagnosis ◽  
Semi Arid

Abstract For mitigation of environmental problems generated by bad water resource management, the first step is to develop methods for effective diagnosis. The potential bioindicator, mainly in the benthic community, in the evaluation of water quality is the structure of the community, associated with magnitude of environmental impact. The aim of the present study was to evaluate the effectiveness of abundance biomass curves (ABC) as tools to estimate ecological quality in reservoirs in the Brazilian semi-arid region. Two reservoirs, Epitácio Pessoa and Argemiro de Figueiredo were selected. These reservoirs are located in the watershed of the Paraíba River, in Northeast Brazil. Sampling was done at 40 sites in the littoral region of each reservoir, during the periods of higher and lower water volume in the reservoirs. ABC for semi-arid region reservoirs showed disparate results for biological and environmental indicators, because they had a better relationship with momentary variables (physical and chemical parameters). This may be related to the high occurrence of exotic species, principally Corbicula largillierti, which has a high biomass, in association with a severe drought period. ABC must thus be used with parsimony and combined with other indicators, for an accurate and coherent characterization.

scholarly journals Diversity and structure of microcrustacean assemblages (Cladocera and Copepoda) and limnological variability in perennial and intermittent pools in a semi-arid region, Bahia, Brazil

2011 ◽  
Vol 101 (4) ◽  
pp. 317-324 ◽  
Author(s):  
Nadson R. Simões ◽  
Sylvia M. M. S. Ribeiro ◽  
Sérgio L. Sonoda
Keyword(s):  
Electrical Conductivity ◽  
Arid Region ◽  
Suspended Solids ◽  
Diversity Index ◽  
Total Alkalinity ◽  
Water Volume ◽  
Aquatic Environments ◽  
Physical Factors ◽  
Semi Arid Region ◽  
Semi Arid

Temporary wetlands undergo recurrent drought due to the scarcity of water, which disrupts the hydrological connectivity with adjacent aquatic systems. However, some environments retain water for longer periods, allowing greater persistence of the community. The current study evaluated differences in the microcrustacean assemblages and limnological variability between perennial and intermittent pools in a semi-arid region of Brazil. The abiotic features (water temperature, pH, total alkalinity, electrical conductivity and depth) of intermittent pools were affected more than perennial pools due to loss of water volume. This may have contributed to a higher average richness and diversity index in some intermittent pools and differences in the structure of the assemblages. The lowest species richness and diversity were recorded where physical factors, such as a large quantity of suspended solids and variability in the electrical conductivity of the water and pH, make the environment unsuitable for these organisms. These results suggest that community development in intermittent pools is interrupted by the dry season; when the water returns, due to rainfall or rising groundwater, each pond undergoes a different process of colonization. In these circumstances, the biological importance of temporary aquatic environments is clear, since such pools provide shelters and have an important role in the maintenance of the regional diversity of aquatic environments.

scholarly journals ECOLOGIA DE PEIXES DE RIACHOS INTERMITENTES

2021 ◽  
Vol 25 (02) ◽  
pp. 605-619
Author(s):  
Bianca de Freitas Terra ◽  
◽  
Elvio Sergio Figueredo Medeiros ◽  
Jorge Iván Sánchez Botero ◽  
José Luis Costa Novaes ◽  
...  
Keyword(s):  
Arid Region ◽  
Riparian Vegetation ◽  
Hydrological Cycle ◽  
Future Research ◽  
Intermittent Streams ◽  
Species Introduction ◽  
The Past ◽  
Semi Arid Region ◽  
Semi Arid

The ecology of fish from intermittent streams in the Brazilian semi-arid region is still little known. In the past twenty years, the number of researchers dedicated to this topic has increased considerably. However, significant gaps still exist when compared to the perennial streams of other regions of Brazil. Questions that address seasonal variations come up against the determination of capture methods and techniques that are efficient in the different phases of the hydrological cycle. In addition, techniques widely used in perennial systems, such as electrofishing, in most cases, have not been effective. Aspects related to biology, physiology, behavior, functional and taxonomic ecology of fish still need to be investigated taking into account seasonal and spatial scale variations. In view of the growing transformation imposed on the Brazilian semi-arid region by the extensive use of natural resources and by climate change, aquatic environments and their biodiversity are threatened by the transformation of riparian vegetation, the sewage release, the species introduction, the modification of its course and artificial perennialization. Thus, we will present and discuss, in this paper, the studies developed on the ecology of fish in the intermittent streams of the Brazilian semi-arid region and the gaps and challenges to be faced by future research.

scholarly journals Spatio-temporal variation of cyanobacteria and cyanotoxins in public supply reservoirs of the semi-arid region of Brazil

2019 ◽  
Vol 79 (1) ◽  
Author(s):  
Ranielle Daiana dos Santos Silva ◽  
Juliana Santos Severiano ◽  
Dayany Aguiar de Oliveira ◽  
Camila Ferreira Mendes ◽  
Vanessa Virgínia Barbosa ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Secondary Metabolites ◽  
Arid Region ◽  
Cyanobacterial Blooms ◽  
Cylindrospermopsis Raciborskii ◽  
Water Volume ◽  
Public Supply ◽  
Bioactive Secondary Metabolites ◽  
Semi Arid Region ◽  
Semi Arid

Cyanobacteria harmful algal blooms (CyanoHABs) have become increasingly frequent and intense in public supply reservoirs as a result of eutrophication and global climate change. The semi-arid region of Brazil has a well documented history of CyanoHABs but the underlying factors that control the excessive proliferation of these organisms and the production of their bioactive secondary metabolites are not comprehensively understood. This study aimed to identify the environmental factors that explain the spatial and temporal variations in the abundance of cyanobacteria and the concentration of cyanotoxins (microcystins, saxitoxins, and cylindrospermopsin) in semi-arid reservoirs. The following hypotheses were tested: (a) the largest biovolumes of potential toxin producing cyanobacteria occur when cyanotoxin concentrations are highest; and (b) the environmental factors that explain variations in biovolume of cyanobacteria also explain changes in cyanotoxins concentrations. Samples were taken from four reservoirs located in the Northeast region of Brazil, over a three-month period (October 2016 and February and June 2017). Of the 24 species of cyanobacteria identified, 13 were potentially toxin-producing. Physicochemical variables such as water volume of the reservoir, water transparency, soluble reactive phosphorus, and total phosphorus explained the abundance of cyanobacteria and the levels of cyanotoxins. These results corroborate the hypothesis that similar physicochemical conditions influence the abundance and diversity of cyanobacteria and cyanotoxins. Cyanobacterial blooms composed of more than one potential toxin producing species were observed in the studied reservoirs, where potential microcystin-producing species were the most common. Microcystins and saxitoxins were detected in all the reservoirs studied, while cylindrospermopsin and the cyanobacterium Cylindrospermopsis raciborskii were simultaneously recorded in only one reservoir (Camalaú Reservoir). Cylindrospermopsin was only detected in a reservoir for the first time in the State of Paraíba. Canonical redundancy analysis showed that the cyanotoxins were related to potential toxin producing species. These results corroborate the proposed hypothesis that there is a correlation between cyanotoxins and the biomass of potential producers. Also, there were situations where cyanotoxins were detected without the presence of potential producers. These results demonstrate the need for reassessment of potential toxin producing species of cyanobacteria in semi-arid reservoirs. This may lead to the identification and characterization of novel producers of these bioactive secondary metabolites.

The Molecular Characterization and Biological Assessment of the Leaves Extracts of Loofah Reveal their Nutraceutical Potential

2020 ◽  
Vol 11 ◽  
Author(s):  
Takoua Ben Hlel ◽  
Feten Belhadj ◽  
Fatih Gül ◽  
Muhammed Altun ◽  
Ayşe Şahin Yağlıoğlu ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Phenolic Compounds ◽  
Hela Cell ◽  
Arid Region ◽  
Biological Properties ◽  
Biological Assessment ◽  
Omega 3 ◽  
Hela Cell Lines ◽  
Semi Arid Region ◽  
Semi Arid

Background:: Luffa cylindrica is a plant that is widely distributed in Africa and Asia and it can be grown in regions with tropical or subtropical climates. Few patents dealt with Loofah biological properties, including some functional foods formulated from its leaves. Objective:: This study aimed to structurally and functionally characterize the bioactive compounds of L. cylindrica leaves grown in two different environments. Methods:: The extracts of L. cylindrica leaves collected from two Tunisian locations: Essouasi (LE), a semi-arid region and Medenine (LM) an arid region, were investigated for their phenolic compounds and fatty acids using HPLC/TOF-MS and GCMS techniques respectively. Furthermore, the antioxidant capacity was evaluated with DPPH, Chelating effect, Hydroxyl radical and Superoxide anion scavenging activities while the anticancer activity against HeLa cell lines was assessed using xCELLigence real time cell analyzer and lactate dehydrogenase cytotoxicity assay. Results:: The antiproliferative capacity of both extracts was time and dose-dependent with LE presenting the lowest HeLa cell index (CI = 0.035 ± 0.018, 250 μg/ml). LE also showed the best cytotoxic capacity (56.49 ± 0.8%) and antioxidant potential (IC50 = 54.41 ± 1.12 μg/ml for DPPH and 12.12 ± 0.07 μg/ml for chelating effet). 14 phenolic compounds were detected in LE with ferulic acid being the major compound (5128.5 ± 4.09 μg Phenols/g) while LM had only 6 phenolics. GCMS analysis showed the presence of omega-3 fatty acids in LE. Conclusions:: Our findings suggest that L. cylindrica leaves, especially when collected from semi-arid regions, are promising for formulating nutraceuticals of interest.

Space-time monitoring of soil organic carbon content across a semi-arid region of Australia

2021 ◽  
Vol 24 ◽  
pp. e00367
Author(s):  
Patrick Filippi ◽  
Stephen R. Cattle ◽  
Matthew J. Pringle ◽  
Thomas F.A. Bishop
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Carbon Content ◽  
Arid Region ◽  
Space Time ◽  
Organic Carbon Content ◽  
Soil Organic Carbon Content ◽  
Semi Arid Region ◽  
Semi Arid
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