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1.
Acta Medica Philippina ; : 80-95, 2022.
Article in English | WPRIM | ID: wpr-988142

ABSTRACT

Introduction@#The Lancet Countdown used Global Burden of Disease (GBD) data to track mortality from diseases influenced by climate change. The Philippines is one of the most vulnerable nations to climate change. @*Objective@#This study aimed to provide summative data on climate change and health-environmental factors based on several large databases. It looked into the correlation of climate change to selected health variables and correlated environmental factors to health chosen variables in the Philippines. @*Methods@#The database was assembled through a compilation of different secondary data. Climate change variables were acquired from the Global Burden of Disease (GBD 2017) Study on Health-related Sustainable Development Goals Indicators from 1990 to 2030. The data for the Philippines were obtained. These indicators include air pollution mortality, disaster mortality, household air pollution, malaria incidence, mean PM2.5, non-communicable disease mortality, neglected tropical diseases mortality, unimproved sanitation, and unsafe water. The resulting database was analyzed using exploratory data analysis techniques with descriptive statistics and line graphs to analyze trends over the years. Then Pearson correlation analysis was done to explore the linear relationship between health indicators, climate indicators, and environmental indicators. @*Results@#The study results showed that the trend in the Philippines for air pollution mortality, household air pollution, malaria incidence, and neglected tropical diseases mortality is in a downward direction. However, non-communicable disease mortality was constantly increasing from 41.99 in 1990 to 55.00 in 2016. Meanwhile, the mean temperature is significantly negatively correlated to household air pollution, malaria incidence, and neglected tropical diseases and significantly correlated with non-communicable diseases. Also, NOAA adjusted sea level is significantly positively correlated with air pollution mortality, malaria incidence, disaster mortality, and non-communicable diseases. It is negatively correlated with malaria incidence and neglected tropical diseases prevalence. Global mean CO2 is significantly negatively correlated with household air pollution, malaria incidence, and neglected tropical diseases prevalence. On the other hand, it was significantly and positively correlated with air pollution mortality and non-communicable diseases mortality. Household air pollution health risk was significantly positively correlated to mean PM2.5 levels in the Philippines. Unimproved sanitation was positively correlated with household air pollution, malaria incidence, and neglected tropical disease prevalence. @*Conclusion@#As recordings of heat index increased, there was a correlation with NCD, Malaria, Disaster, and NTD infection mortality. With the evidence of the correlation of increasing temperature and pollution to health, the urgency to focus on addressing these problems was present in this study. Further research may help in policymaking to target drivers of pollution which affect extreme climate changes.


Subject(s)
Climate Change , Air Pollution
2.
Neotrop. ichthyol ; 19(2): e200128, 2021. tab, graf
Article in English | LILACS, VETINDEX | ID: biblio-1279482

ABSTRACT

The coastal basins of southeastern Brazil are influenced by climatic changes that caused sea-level oscillations during the Pleistocene. These marine transgressions and regressions can generate isolation and connection among coastal rivers. In this region, freshwater fishes are excellent models for phylogeographic studies because their distributions may have been affected by geographical and ecological changes resulting from these processes. Therefore, the main objective of this study was to evaluate the effects of Pleistocene sea-level changes on the genetic structure of the loricariid Hisonotus leucofrenatus throughout its area of occurrence. Two genes were sequenced: Cytochrome Oxidase subunit 1 (mitochondrial gene) and rpS7 ribosomal protein gene intron 1 (nuclear gene) from specimens representing 14 river drainages. The genetic data corroborate a divide for freshwater fish by the Serra do Tabuleiro mountain in Santa Catarina State. This divide determines two main genetic groups in H. leucofrenatus: one group to the south and one to the north of this mountain range. The genetic structure observed coincide with the limits of estimated paleodrainage systems for the region, supporting that marine transgressions and regressions during the Pleistocene influenced the biogeographical history of H. leucofrenatus.(AU)


As bacias costeiras do sul do Brasil são influenciadas pelas mudanças climáticas que causaram oscilações no nível do mar durante o Pleistoceno. Essas transgressões e regressões marinhas geraram isolamento e conexão entre os rios. Nessa região, as espécies de peixe são excelentes modelos para estudos filogeográficos, pois suas distribuições podem ter sido afetadas por mudanças históricas e ecológicas decorrentes desses processos. Portanto, o objetivo principal deste estudo foi testar os efeitos das alterações do nível do mar durante o Pleistoceno na estrutura genética das populações do loricarídeo Hisonotus leucofrenatus ao longo de sua área de ocorrência. Dois genes foram sequenciados: Citocromo Oxidase subunidade 1 (gene mitocondrial) e o intron 1 da proteína ribossomal rpS7 (gene nuclear) de espécimes representando 14 bacias de drenagens. A estrutura genética observada corrobora uma divisão para peixes de água doce separada pela Serra do Tabuleiro, em Santa Catarina. Essa divisória determina dois grupos principais genéticos em H. leucofrenatus: um grupo ao sul e outro ao norte desse divisor. A estrutura genética também coincide com os limites dos sistemas de paleodrenagens estimados para a região, sustentando que as transgressões e regressões marinhas durante o Pleistoceno influenciaram a história biogeográfica de H. leucofrenatus.(AU)


Subject(s)
Catfishes/anatomy & histology , Catfishes/genetics , Genetic Structures , Phylogeography , Fishes , Climate Change , Sea Level
3.
Neotrop. ichthyol ; 18(3): e190114, 2020. tab, graf, ilus, mapas
Article in English | LILACS, VETINDEX | ID: biblio-1135397

ABSTRACT

The coastal basins in Northeastern Brazil used in this study make up two different ecoregions for freshwater fishes (Amazonas estuary and coastal drainages, and Parnaiba) and two areas of endemism for Characiformes (Maranhão and Parnaíba), and exhibits a diversified yet poorly explored freshwater fish fauna. The population structure and biogeography of two migratory freshwater fish species that are commercially exploited from Maranhão and Parnaíba regions were herein analyzed. Molecular sequence data and statistical analyses were used to estimate haplotypes networks and lineage divergence times and correlated with hydrographic history of drainage and paleodrainages of the region. A total of 171 sequences was produced for both species, Schizodon dissimilis (coI, n = 70) and Prochilodus lacustris (D-loop, n = 101). All analyses identified the presence of three genetically delimited groups of S. dissimilis and six groups of P. lacustris. The lineage time analyses indicate diversification among these species within the past 1 million year. The results indicate the influence of geodispersal in the formation of the ichthyofauna in the studied area through headwater stream capture events and reticulated connections between the mouths of rivers along the coastal plain due to eustatic sea level fluctuations.(AU)


As bacias costeiras do nordeste do Brasil usadas neste estudo compõem duas ecorregiões diferentes para peixes de água doce (Estuário do Amazonas e drenagens costeiras e Parnaíba) e duas áreas de endemismo para Characiformes (Maranhão e Parnaíba), exibindo uma diversificada e ainda pouco explorada fauna de peixes de água doce. A estrutura populacional e biogeografia de duas espécies migradoras de peixes de água doce exploradas comercialmente nas regiões do Maranhão e Parnaíba foram analisadas. Dados de sequências moleculares e análises estatísticas foram utilizados para estimar redes de haplótipos e tempos de divergência entre linhagens, e foram correlacionados com a história hidrográfica das drenagens e paleodrenagens da região. Um total de 171 sequências foram geradas para ambas espécies, Schizodon dissimilis (coI, n = 70) e Prochilodus lacustris (D-loop, n = 101). Todas análises identificaram a presença de três grupos geneticamente delimitados para S. dissimilis e seis grupos para P. lacustris. A análise de tempo de divergência das linhagens indicou uma diversificação entre estas espécies nos últimos 1 Ma. Os resultados indicam influência da geodispersão na formação da ictiofauna do Maranhão, devido eventos de capturas de cabeceira e conexões reticuladas entre as fozes dos rios ao longo da planície costeira devido às flutuações eustáticas do nível do mar.(AU)


Subject(s)
Animals , Characiformes/genetics , Fishes/genetics , Molecular Sequence Data , Sea Level , Phylogeography
4.
Article | IMSEAR | ID: sea-204809

ABSTRACT

This study projects the impact of sea level rise on Nigeria’s coastal city of Calabar in Cross River State. Data for the study were obtained from both secondary and primary sources through the use of the internet and questionnaire administration respectively. The data were analysed using the geographical information systems (GIS), frequency tables and percentages. The results revealed that at 0.3 m rise in sea level, about 4.56% of the total land area will be covered with flood water. This would affect 159 houses, with approximately 1,431 persons. Further, at 3.0 m rise in sea level, about 10.10% of the area will be flooded, affecting 2012 houses with an estimated population of 18,108 persons. Again, the resilience of the residents to the vagaries of flooding by sea level rise is generally low due to very low income and lack of awareness. The study concluded that Calabar City is vulnerable to the impact of sea level rise which is primarily caused by climate change. Therefore, awareness campaign on the impact of flooding by sea level rise on coastal communities should be carried out by the appropriate agencies of government in the State.

5.
Neotrop. ichthyol ; 16(3): [e180019], out. 2018. tab, mapas, ilus, graf
Article in English | LILACS, VETINDEX | ID: biblio-963963

ABSTRACT

The eastern coastal basins of Brazil are a series of small and isolated rivers that drain directly into the Atlantic Ocean. During the Pleistocene, sea-level retreat caused by glaciations exposed the continental shelf, resulting in enlarged paleodrainages that connected rivers that are isolated today. Using Geographic Information System (GIS), we infer the distribution of these paleodrainages, and their properties for the east Brazilian coast. Specifically, using elevation/bathymetric data for the largest sea-level retreats during the Pleistocene, the paleodrainages, their area and the number of contemporary basins connected by each palaeodrainage, was inferred. For the 145 inferred paleodrainages, total paleodrainage area is strongly correlated with the contemporary area encompassed by each paleodrainage, as well as with the number of contemporary basins encompassed by a paleodrainage. Differences in the continental shelf exposure along the coast affected the degree of past connectivity among contemporary rivers. With our results freely available, we discuss how paleodrainages have tremendous utility in biological studies, especially in regions with limited geologic data. With respect to the diverse ichthyofauna of the Brazilian coast, and its high endemism, we highlight how the inferred paleodrainages provide a backdrop to test hypotheses about the effect of past riverine connectivity on diversity patterns.(AU)


As bacias costeiras do leste do Brasil são formadas por uma série de rios pequenos e isolados que drenam diretamente para o Oceano Atlântico. Durante o Pleistoceno, o recuo do nível do mar causado por glaciações expôs a plataforma continental, resultando em paleodrenagens amplas que conectaram rios atualmente isolados. Usando o Sistema de Informações Geográficas (GIS), inferimos a distribuição destas paleodrenagens e suas propriedades ao longo da costa leste do Brasil. Especificamente, utilizando dados de elevação/batimetria para as maiores regressões marinhas do Pleistoceno, inferimos as paleodrenagens, suas áreas e quantas bacias contemporâneas foram conectadas por cada paleodrenagem. Para as 145 paleodrenagens inferidas, uma forte correlação é observada entre a área das paleodrenagens e a área atualmente exposta de cada paleodrenagem, bem como a quantidade de bacias contemporâneas conectadas por uma paleodrenagem. Diferenças na exposição da plataforma continental ao longo da costa afetaram o grau de conectividade passada entre os rios. Com estes resultados publicamente disponíveis, discutimos como as paleodrenagens são extremamente úteis para estudos biológicos, especialmente em regiões com dados geológicos limitados. A respeito da diversa ictiofauna da costa brasileira e seus altos níveis de endemismo, destacamos como estas paleodrenagens fornecem uma base importante para o teste de hipóteses a respeito do efeito da conectividade passada dos rios nos padrões de diversidade biológica.(AU)


Subject(s)
Animals , Ecology , Fishes/classification
6.
Neotrop. ichthyol ; 14(2)2016. mapas, tab, graf
Article in English | LILACS | ID: lil-796525

ABSTRACT

Coastal and marine environments are characterized by a lack of evident physical barriers or geographic isolation, and it may be difficult to understand how divergence can arise and be sustained in marine environments. The identification of 'soft' barriers is a crucial step towards the understanding of gene flow in marine environments. The marine catfishes of the family Ariidae are a demersal group with restricted migratory behavior, no pelagic larval stages, and mechanisms of larval retention, representing a potentially useful model for the understanding of historical processes of allopatric speciation in the marine environment. In the present study, two lineages of the Coco sea catfish, Bagre bagre , were recognized from their complete segregation at both mitochondrial and morphological levels. One lineage is distributed between Venezuela and the northern coast of Brazil, including the semiarid northeast coast, while the second lineage is found on the eastern coast of Brazil, including the humid northeast coast. Based on distribution area, habitats preference, and genetic variability, inferences are made in relation to biogeography and demography of lineages in Atlantic coast of South America.


Ambientes marinhos costeiros são caracterizados pela falta de barreiras físicas evidentes e ausência de isolamento geográfico, sendo difícil compreender como diferentes linhagens podem surgir e ser mantidas nestes ambientes. A identificação de barreiras permeáveis é um passo importante para a compreensão do fluxo gênico em ambientes marinhos. Os bagres marinhos da família Ariidae são um grupo demersal, com mecanismos de retenção larval e sem comportamento migratório ou estágio larval pelágico, representando um grupo potencialmente útil para a compreensão de processos históricos de especiação alopátrica no ambiente marinho. No presente estudo, duas linhagens do bandeirado ou bagre de fita, Bagre bagre , são reconhecidas com base na completa segregação mitocondrial e morfológica. Uma linhagem é encontrada da Venezuela à costa norte do Brasil, incluindo a costa nordeste semi-árida, enquanto a segunda linhagem é encontrada na costa leste e sudeste do Brasil, incluindo a costa nordeste úmida. Com base na área de distribuição, habitat preferencial e a variabilidade genética, inferências são feitas em relação à biogeografia e demografia das duas linhagens na costa do Atlântico da América do Sul.


Subject(s)
Animals , Catfishes/classification , Catfishes/genetics , Phylogeography , Pedigree , Sea Level
7.
Rev. biol. trop ; 63(supl.1): 29-46, abr. 2015. tab, graf
Article in Spanish | LILACS, SaludCR | ID: biblio-958126

ABSTRACT

Resumen Se estudió la dinámica de las mareas y el oleaje frente al Humedal Nacional Térraba-Sierpe (HNTS) y su relación con los procesos de erosión y la muerte del manglar en esta región. Se encuentra que un aumento relativo del nivel del mar, ya sea generado por el basculamiento de las costas, o por calentamiento global, es el responsable de crear una nueva plataforma para el oleaje y está modificando el perfil de la costa y cambiando el tipo de sedimento sobre el cual crece el manglar. Una mayor deposición de sedimentos sobre la región norte de este delta, mantiene el equilibrio de este sistema en esta zona, donde más bien hay una ganancia de sedimentos en la isla al frente de la desembocadura del Río Grande de Térraba. Un menor aporte de sedimentos del Rio Sierpe está generando una migración tierra adentro de este sistema estuarino frente a esta región, lo cual es un síntoma de un aumento relativo del nivel del mar. Los escenarios futuros sobre una mayor energía del oleaje, y de un continuo aumento del nivel del mar, no permitirán un equilibrio en la dinámica de los sedimentos, especialmente sobre la parte sur de este delta, por lo que continuará perdiendo la cobertura del manglar en este sistema estuarino.


Abstract The Térraba-Sierpe Reserve has the largest mangrove in Costa Rica but has suffered from changes in sea level. I used published data to analyze the area and found that sea level rise, generated by coast subsidence or global warming, created a new platform for waves and changed the beach profile and sediment type. Increased sediment deposition on the north maintains the balance of this system, with a sediment gain on the island in front of the Térraba river mouth. A lower sediment output from the Sierpe river is generating a landward delta migration, especially in the southern part, a symptom of local sea level rise. Future scenarios of greater wave energy and additional sea level rise will not allow a dynamic sediment balance, especially on the southern part of the delta, and will generate a loss mangrove cover. Rev. Biol. Trop. 63 (Suppl. 1): 29-46. Epub 2015 April 01.


Subject(s)
Erosion/adverse effects , Wetlands , Global Warming , Tidal Waves , Costa Rica , Oceanography
8.
Article in English | IMSEAR | ID: sea-162615

ABSTRACT

The Perdido and Wolf Bay system in Alabama, USA, is an estuarine system linking the freshwater from the Perdido and Wolf Bay watersheds and the tidal saltwater from the Gulf of Mexico through Perdido Pass, Dolphin Pass, and the Gulf Intracoastal Waterway. A three dimensional hydrodynamic model using Environmental Fluid Dynamics Code (EFDC) was developed and used to analyze complex and dynamic flow, salinity, and temperature distributions in the system. The external driving forces for the model include the river discharges from natural and urban watersheds, atmospheric winds, and astronomical tidal elevations at the open boundaries where flow exchange takes place. Simulated water surface elevation, temperature, and salinity were compared against the field data at several observation stations in 2008 and 2009 with good agreement (coefficient of determination R2 = 0.92 between the measured and the modeled water surface elevations). The calibrated EFDC model was used to examine responses of the system to high, mean, and low inflows from streams and the sea level rise in the open boundaries under climate change. The concept of the age of water was applied to understand pollutant transport in the system. The age of water reveals dynamic and complex interactions between tides from the Gulf of Mexico and inflows from the streams. The age of water is less than 20 days under the 2-year high inflows and up to 160 days under 7Q10 low inflows. Under mean inflow conditions, the age of the tracer released from Wolf Bay is 50–70 days in the lower Perdido Bay and larger than that in the upper Perdido Bay, indicating a strong interaction between tides and inflows, which results in recirculation of flow and pollutants. The age of water is projected to increase up to 60 days under estimated sea level rise scenarios.

9.
Article in English | IMSEAR | ID: sea-162601

ABSTRACT

Assessing the impacts of climate changes on water quality requires an understanding of the biogeochemical cycling of trace metals. Evidence from research on alluvial aquifers and coastal watersheds shows direct impacts of climate change on the fate and transformation of trace metals in natural environments. The case studies presented here use field data and numerical modeling techniques to test assumptions about the effects of climate change on natural arsenic contamination of groundwater in alluvial aquifers and mercury bioaccumulation in coastal salt marshes. The results show that the rises of sea level and river base during the warm Holocene period has led to an overall increase in groundwater arsenic concentration due to the development of reducing geochemical

10.
An. Fac. Med. (Perú) ; 73(3): 183-190, jul.-set. 2012. ilus, tab
Article in Spanish | LILACS-Express | LILACS, LIPECS | ID: lil-692322

ABSTRACT

Introducción: Las poblaciones que habitan en altitudes elevadas presentan un pequeño retardo en el crecimiento físico lineal. Esta diferencia es atribuida al fenómeno de la hipoxia, así como a factores socioeconómicos, nutricionales y medio-ambientales. Objetivo: Comparar el crecimiento físico de niños escolares peruanos de zonas urbanas del nivel del mar (150 msnm) y de altitud moderada (2 320 msnm). Diseño: Estudio descriptivo/comparativo, diseño ex post facto. Institución: Facultad de Educación Física, Universidad estadual de Campinas, SP, Brasil; y Universidad Nacional de Educación, Lima, Perú. Participantes: Escolares. Intervenciones: Se seleccionó un total de 1 153 escolares de 6 a 11 años, de ambos géneros, procedentes de dos regiones geográficas del Perú, siendo uno de nivel del mar (NM) (Lima Este; 150 msnm) y la otra de altitud moderada (AM) (Arequipa Sur; 2 320 msnm). La selección de los escolares del NM fue de forma no-probabilística intencional, totalizando una sub-muestra de 672 niños. Los escolares de altitud moderada, escogidos de manera probabilística estratificada, estuvieron representados por 792 niños, de un total de 5 627 escolares. Se evaluó la edad y las variables de crecimiento físico de masa corporal y estatura. Los resultados fueron analizados utilizando la media aritmética (X), desviación estándar (DE) y distribución percentilar. Para comparar los grupos, se usó la prueba de t student para muestras independientes (p<0,001), y las distribuciones de p5, p10, p25, p50, p75, p85, p90 y p95 fueron comparadas de acuerdo con la fracción 100 log (percentil de la referencia/percentil calculado). Principales medidas de resultados: Crecimiento de masa corporal y estatura. Resultados: Los niños de ambos géneros y de todas las edades del NM presentaron mayor masa corporal en relación a los niños de AM. Sin embargo, respecto a la estatura, no hubo diferencias significativas, presentando similar comportamiento de crecimiento desde los 6 hasta los 11 años. Conclusiones: Estos hallazgos sugieren que el grado de estrés hipóxico en la altitud moderada no afectaría el crecimiento en estatura de niños escolares de Arequipa (2 320 msnm). A su vez, los niños a nivel del mar presentaron tendencia al sobrepeso y obesidad.


Background: Populations living at high altitudes have a small delay in linear physical growth. These differences are attributed to hypoxia as well as to socioeconomic, nutritional and environmental factors. Objectives: To compare physical growth of school children in Peruvian urban areas at sea level (150 meters above sea level) and moderate altitude (2 320 m.a.s.l.). Design: Ex post facto design, descriptive comparative study. Institution: Faculty of Physical Education, State University of Campinas, SP, Brazil, and Universidad Nacional de Educacion, Lima, Peru. Participants: School children. Interventions: A total of 1 153 boys and girls aged 6 to 11 years were selected from two Peruvian geographical regions, one at sea level (SL) (Lima-East; 150 m.a.s.l.) and the other at moderate altitude (MA) (urban Southern Arequipa; 2 320 m.a.s.l.). School children at SL were chosen in non-probabilistic intentional way, totaling a subsample of 672 children. Pupils at moderate altitude (MA) were selected by stratified probability, resulting in 792 children from a total of 5 627 school children. Decimal osmolality and body mass and height, variables of physical growth, were assessed. Results were analyzed using arithmetic mean (X), standard deviation (SD) and percentile distribution. ‘T’ student test was used to compare groups, and independent samples (p <0.001) and distributions (p5, p10, p25, p50, p75, p85, p90 and p95) were compared according to the fraction 100 log (percentile of the reference/percentile calculated). Main outcome measures: Body mass and height growth. Results: Children of both genders and all ages at sea level had higher body mass in relation to children at moderate altitude. However, height did not differ significantly, with similar growth behavior at ages 6 to 11. Conclusions: These findings suggest that moderate altitude hypoxic stress does not affect stature growth in Arequipa’s (2 320 m.a.s.l.) school children. Children at sea level had a tendency to overweight and obesity.

11.
An. acad. bras. ciênc ; 83(4): 1221-1230, Dec. 2011. ilus, tab
Article in English | LILACS | ID: lil-607422

ABSTRACT

The limits between sea and land were estimated at "Pulso" beach located in the Southeastern Brazilian shelf (φ = 23°33/17.4886"S; Λ = 045° 13'13.0504"W - WGS84), between the island of São Sebastião and the city of Ubatuba, SP, Brazil. The relative sea level of the year 1831 at "Pulso" beach, as per Brazilian law Number 9760 dated from 1946, was estimated and materialized. The retro-estimation allowed the demarcation of the Legal Sea-Land Limits at "Pulso" beach as per the terms of the law. The accuracy of the procedure for the transference of the long-term sea level from the research station of Ubatuba to "Pulso" beach was assessed by parallel work of geometrical leveling referred to the IBGE (Brazilian Institute of Geography and Statistics) geodetic network. The motivation, the hypotheses (Brest, Cananeia and IPCC) and the methods here used are described, together with a short history of the Legal Sea-Land Limits. The results indicated that the legal Sea-Land Limits at "Pulso" beach are well within the beach area. They were determined as per law 9760, and there is the need to reactivate the national network of sea level gauge.


Os limites entre mar e terra foram estimados na praia chamada Pulso, localizada na costa sudeste do Brasil (φ = 23°33'17, 4886"S; Λ = 045°13'13, 0504"W) entre a Ilha de São Sebastião e a cidade de Ubatuba, no Estado de São Paulo, SP, Brasil. O nível relativo do mar do ano de 1831 na praia do Pulso, ou "Praia do Pulso" (PP), foi estimado e materializado, de acordo com a Lei brasileira Número 9760 de 1946. A acurácia do procedimento foi acompanhada por trabalho paralelo de nivelamento geométrico referido ao sistema nacional de geodésia do IBGE (Instituto Brasileiro de Geografia e Estatística). A motivação, as hipóteses (Brest, Cananeia e IPCC) e os métodos utilizados são descritos, acompanhados por um breve histórico dos "Terrenos de Marinha". Os resultados indicaram que os limites em (PP) estão bem dentro da área da praia. Eles fora deterinados de acordo co a Lei No. 9760 e há a necessidade de reativar a rede nacional de medidores do nível do mar.

12.
An. acad. bras. ciênc ; 83(3): 817-834, Sept. 2011. ilus, tab
Article in English | LILACS | ID: lil-595541

ABSTRACT

The aim of this work was to generate an inventory of the data on radiocarbon datings obtained from sediments of the São Paulo Bight (southern Brazilian upper margin) and to analyze the data in terms of Late Quaternary sedimentary processes and sedimentation rates. A total of 238 radiocarbon datings from materials collected using differents ampling procedures was considered for this work. The sedimentation rates varied from less than 2 to 68 cm.kyr-1. The highest sedimentation rate values were found in a low-energy (ría type) coastal system as well as in the upwelling zones of Santa Catarina and Cabo Frio. The lowest rates were found on the outer shelf and upper slopes. Our results confirm the strong dependency of the shelf currents, with an emphasis to the terrigenous input from the Río de La Plata outflow which is transported via the Brazilian Coastal Current, as well as of the coupled Brazil Current - Intermediate Western Boundary Current (BC-IWBC) dynamics on the sedimentary processes. At least three indicators ofthe paleo sea level were found at 12200 yr BP (conventional radiocarbon age) (103 meters below sea level - mbsl),8300-8800 cal yr BP (13 mbsl) and 7700-8100 cal yr BP (6 mbsl).


O objetivo deste trabalho foi a geração de um inventário dos dados de datação de radiocarbono obtidos de sedimentos do Embaiamento de São Paulo (Margem Continental Superior do Sul do Brasil) e analisar os dados em termos de processos sedimentares quaternários e taxas de sedimentação. Um total de238 datações ao radiocarbono de materiais coletados com autilização de procedimentos amostrais diferentes foi considerado neste trabalho. As taxas de sedimentação variaram de menor que 2 a 68 cm.kyr-1. As taxas de sedimentação mais altas foram encontradas em um sistema costeiro de baixa energia (tipo ría), bem como nas zonas de ressurgência de Santa Catarina e Cabo Frio. As taxas mais baixas foram encontradas na plataforma externa e talude superior. Nossos resultados confirmam a forte dependência do sistema de correntes de plataforma, com ênfase no aporte terrígeno oriundo do Rio daPrata, transportado através da Corrente Costeira do Brasil, e da dinâmica da Corrente do Brasil - Corrente de Contorno Intermediária (CB-CCI) nos processos sedimentares. Pelo menostrês indicadores de paleo-níveis marinhos foram encontrados a 12200 anos AP (idade radiocarbônica convencional) (103 metros abaixo do nível do mar atual - manm), 8300-8800 cal anos AP (13 manm) e 7700-8100 cal anos BP (6 manm).


Subject(s)
Carbon Radioisotopes/analysis , Geologic Sediments , Brazil , Oceans and Seas , Radiometric Dating/methods
13.
An. acad. bras. ciênc ; 82(2): 451-465, June 2010. ilus, mapas, tab
Article in English | LILACS | ID: lil-548425

ABSTRACT

The modern vegetation types, sedimentary sequences, pollen records and radiocarbon dating obtained from three sediment cores from Calçoene Coastal Plain were used to provide a palaeoecological history during the late Holocene of Amapá coastal wetland according to flood regime, sea-level and climatic changes. Based on these records, four phases of vegetation development are presented and they probably reflect the interaction between the flow energy to the sediment accumulation and the brackish/freshwater influence in the vegetation. This work suggests interchanges among time periods characterized by marine and fluvial influence. The longitudinal profile did not reveal the occurrence of mangrove in the sediment deposited around 2100 yr B.P. During the second phase, the mud progressively filled the depressions and tidal channels. The mangrove probably started its development on the channel edge, and the herbaceous field on the elevated sectors. The third phase is characterized by the interruption of mangrove development and the increase of "várzea" vegetation that may be due to the decrease in porewater salinity related to a decrease in marine water influence. The last phase is represented by the mangrove and "várzea" increase. The correlation between current patterns of geobotanical unit distribution and palaeovegetation indicates that mangrove and "várzea" forests are migrating over the herbaceous field on the topographically highest part of the studied coast, which can be related to a relative sea-level rise.


Os tipos de vegetação atual, sequências sedimentares, dados de pólen e datações por radiocarbono obtidas em três testemunhos de sedimento da planície costeira de Calçoene foram utilizados para estabelecer uma história paleoecológica durante o Holoceno superior das zonas úmidas costeiras do Amapá conforme as mudanças no regime de inundação, nível do mar e clima. Baseado nestes três registros, quatro fases de desenvolvimento da vegetação são apresentadas e provavelmente refletem a interação entre o fluxo de energia na acumulação do sedimento e a influência das águas salobras e doces na vegetação. Este trabalho sugere alternâncias entre períodos caracterizados por influências marinha e fluvial. O perfil longitudinal não revelou a ocorrência de manguezais nos sedimentos depositados por volta de 2100 anos A.P. Durante a segunda fase, a lama preencheu progressivamente as depressões e canais de maré. Provavelmente, os manguezais iniciaram seu desenvolvimento nas margens dos canais, e os campos herbáceos nos setores elevados. A terceira fase é caracterizada por uma interrupção no desenvolvimento dos manguezais e a expansão da vegetação de várzea devido a uma diminuição na influência das águas marinhas. A última fase é representada pela expansão de manguezais e várzeas. A correlação entre os padrões atuais de distribuição das unidades geobotânicas e a paleovegetação indica que os manguezais e as florestas de várzea estão migrando sobre os campos herbáceos nos setores topograficamente mais elevados do litoral em estudo, o que pode estar relacionado a um aumento do nível relativo do mar.

14.
Interciencia ; 34(12): 851-856, dic. 2009. ilus, tab
Article in English | LILACS | ID: lil-630885

ABSTRACT

In recent years, the availability of accurate ocean tide models has become increasingly important, as tides are the main contributor to disposal and movement of sediments, tracers and pollutants, and also due to a wide range of offshore applications in engineering, environmental observations, exploration and oceanography. Tides can be conventionally predicted by harmonic analysis, which is the superposition of many sinusoidal constituents with amplitudes and frequencies determined by a local analysis of the measured tide. However, accurate predictions of tide levels could not be obtained without a large number of tide measurements by the harmonic method. An application of the back-propagation artificial neural network using long-term and short-term measuring data is presented in this paper. On site tidal level data at Ingeniero White harbor in the inner part of Bahia Blanca estuary, Argentina, will be used to test the performance of the present model. Comparison with conventional harmonic methods indicates that the back-propagation neural network model also predicts accurately the long-term tidal levels.


Durante los últimos años, la disponibilidad de modelos oceánicos cada vez más exactos han aumentado en importancia, por ser las mareas el principal contribuyente para la disposición y movimiento de trazadores, sedimentos y contaminantes, y por una amplia variedad de aplicaciones en ingeniería, observaciones ambientales, exploración y oceanografía. Las mareas pueden ser pronosticadas mediante análisis armónico, que es la superposición de funciones sinusoidales con amplitudes y frecuencias determinadas en un análisis local de registros mareográficos. Sin embargo, la exactitud de las predicciones del nivel de marea por el método armónico no puede obtenerse sin un gran número de mediciones. En este trabajo se presenta una aplicación del método propagación hacia atrás (back-propagation) de redes neuronales empleando datos de corto y de largo plazo. Para medir la precisión del presente modelo se utilizan mediciones de nivel de marea correspondientes al Puerto Ingeniero White, en la parte interna del estuario de Bahia Blanca, Argentina. La comparación con métodos armónicos convencionales indica que las redes neuronales empleando back-propagation también predicen eficientemente los niveles de mareas a largo plazo.


Durante os últimos anos, a disponibilidade de modelos oceânicos cada vez mais exatos têm aumentado em importância, por ser as marés o principal contribuinte para a disposição e movimento de traçadores, sedimentos e contaminantes, e por uma ampla variedade de aplicações em engenharia, observações ambientais, exploração e oceanografia. As marés podem ser prognosticadas mediante análise armônico, que é a superposição de funções sinusoidais com amplitudes e frequências determinadas em uma análise local de registros maregráficos. Entretanto, a exatidão das previsões do nível da maré pelo método armônico não pode obter-se sem um grande número de medições. Neste trabalho se apresenta uma aplicação do método propagação para atrás (back-propagation) de redes neuronais empregando dados de curto e de longo prazo. Para medir a precisão do presente modelo se utilizam medições de nível de maré correspondentes ao Puerto Ingeniero White, na parte interna do estuario de Bahia Branca, Argentina. A comparação com métodos armônicos convencionais indica que as redes neuronais empregando back-propagation também predizem eficientemente os níveis de marés a longo prazo.

15.
Article in Portuguese | LILACS | ID: lil-468009

ABSTRACT

Este estudo apresenta os resultados de um inventário da fauna de lagartos da Marambaia, RJ. Foram registradas 12 espécies de lagartos, distribuídas em sete famílias. Teiidae é a família mais rica (3 spp.), seguida por Gekkonidae (2), Scincidae (2), e Tropiduridae (2), Gymnophthalmidae (1), Leiosauridae (1) e Polychrotidae (1). A composição da comunidade de lagartos da Marambaia é semelhante à de outras localidades do litoral sudeste brasileiro, entretanto a área comporta espécies de distribuição restrita às restingas do Estado do Rio de Janeiro e sob ameaça de extinção, como Cnemidophorus littoralis e Liolaemus lutzae. Também protege espécies típicas de florestas, como os lagartos arborícolas Enyalius brasiliensis e Anolis cf. fuscoauratus. Floresta e restinga são contínuas na Marambaia e representam os hábitats mais ricos em lagartos, reunindo, respectivamente, nove e oito espécies. A possibilidade de perda de variabilidade genética, como resultado do isolamento geográfico, e a aparente dificuldade de recolonização em casos de perda local de diversidade, somadas à modificações das paisagens por atividade antrópica, são fatores preocupantes para a conservação da herpetofauna da Marambaia.


This work presents the results of a survey of the lizard species that occur in Marambaia, RJ. Twelve species of lizards, distributed in seven families were registered. Teiidae is the richest family (3 spp.), followed by Gekkonidae (2), Scincidae (2), Tropiduridae (2), Gymnophthalmidae (1), Leiosauridae (1), and Polychrotidae (1). The lizard fauna of Marambaia is similar to that occurring in other localities in the southeastern coast of Brazil. Nevertheless, Marambaia harbors Cnemidophorus littoralis and Liolaemus lutzae, species restricted to restinga habitats in Rio de Janeiro State and considered under threat. The area also protects typical forest species, including the arboreal lizards Enyalius brasiliensis and Anolis cf. fuscoauratus. Forest and restinga are continuous in Marambaia and represent the richest habitats for lizards, comprising nine and eight species, respectively. The possibility of genetic variability loss due to the geographical isolation of the area, and the apparent difficulty of re-colonization in the case of local loss of diversity, added to environmental modifications caused by human activities, are worrying issues for the conservation of Marambaia herpetofauna.


Subject(s)
Fauna/analysis , Ecosystem/analysis , Ecosystem/adverse effects , Lizards/classification , Lizards/growth & development , Reptiles/classification , Reptiles/growth & development
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