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Comparison of the heterochromatin and telomeric sequences distribuition in chromosomes of 11 species of Amazonian marsupials (Didelphimorphia; Didelphidae)
No full textExploration of oxidative chemistry and secondary organic aerosol formation in the Amazon during the wet season: Explicit modeling of the Manaus urban plume with GECKO-A
No full textThe GoAmazon 2014/5 field campaign took place in Manaus, Brazil, and allowed the investigation of the interaction between background-level biogenic air masses and anthropogenic plumes. We present in this work a box model built to simulate the impact of urban chemistry on biogenic secondary organic aerosol (SOA) formation and composition. An organic chemistry mechanism is generated with the Generator for Explicit Chemistry and Kinetics of Organics in the Atmosphere (GECKO-A) to simulate the explicit oxidation of biogenic and anthropogenic compounds. A parameterization is also included to account for the reactive uptake of isoprene oxidation products on aqueous particles. The biogenic emissions estimated from existing emission inventories had to be reduced to match measurements. The model is able to reproduce ozone and NOx for clean and polluted situations. The explicit model is able to reproduce background case SOA mass concentrations but does not capture the enhancement observed in the urban plume. The oxidation of biogenic compounds is the major contributor to SOA mass. A volatility basis set (VBS) parameterization applied to the same cases obtains better results than GECKO-A for predicting SOA mass in the box model. The explicit mechanism may be missing SOA-formation processes related to the oxidation of monoterpenes that could be implicitly accounted for in the VBS parameterization. © 2020 BMJ Publishing Group. All rights reserved
Interações biosfera-atmosfera em uma savana tropical no leste da Amazônia
Full text linkSensitive heat, latent heat, soil heat and carbon dioxide flux measurements were made
in a natural savanna ecosystem in eastern Amazonia, using the eddy covariance method. Data
collection was carried out in a savanna area in the municipality of Santarém, Pará, from
September to November 2018, a period corresponding to part of the dry season in the region.
In this experimental site, the patterns of variability of the daily cycle for energy and CO2 flows
were analyzed, as well as an attempt to understand the structure of the local turbulence. The
average air temperature in the year 2018 at the savanna site was 29 ºC, being 2 ºC warmer than
the historical average of the region, with the occurrence of occasional and low intensity rain
episodes. The average radiation balance at the surface was 125 W m-2, with an average daily
latent heat flow (LE) in the period of 59 W m-2, while the sensitive heat flow (H) was 69 W m-
2. The average Bowen ratio for the data period was 1.4, representing the preponderance of air
heating processes over evaporative processes. During the day, about 36% of the available
energy (Rn) in the savanna was used in the evapotranspiration process and H corresponded to
51% of Rn on average. In the study's time interval, an incomplete surface energy balance was
observed, with a deficit of 8%. With respect to carbon dioxide flows, the maximum carbon
absorption was -8.8 µmol.m-2 s-1, during the day, while the maximum emission was 4.6 µmol.m-
2
s-1 , during dawn. In general, it was found that, in terms of energy balance, the studied savanna
has characteristics of a typical savanna, despite the more humid climate in this region compared
to other savanna regions. Regarding the structure of turbulence in the savanna atmosphere, it is
not possible to apply the Monin-Obukhov Similarity Theory, following the behavior observed
in the Amazon rainforest, which requires an adaptation of the theory for the biome in the correct
quantification of mass and energy flows.Foram realizadas medidas de fluxos de calor sensível, calor latente, calor no solo e de
dióxido de carbono em um ecossistema de savana natural no leste da Amazônia, utilizando o
método de covariância de vórtices turbulentos. A coleta de dados foi realizada em uma área de
savana no município de Santarém, Pará, de setembro a novembro de 2018, período corresponde
à parte da estação seca na região. Neste sítio experimental, os padrões de variabilidade do ciclo
diário para os fluxos de energia e CO2 foram analisados, assim como buscou-se conhecer a
estrutura da turbulência local. A temperatura média do ar no ano de 2018 no sítio de savana foi
de 29 ºC, sendo 2 ºC mais quente que a média histórica da região, com ocorrência de episódios
de chuva pontuais e de baixa intensidade. O saldo de radiação médio à superfície foi de 125 W
m-2, com fluxo médio diário de calor latente (LE) no período de 59 W m-2, enquanto o fluxo de
calor sensível (H) foi de 69 W m-2. A razão de Bowen média para o período de dados foi de 1,4,
representando a preponderância dos processos de aquecimento do ar frente aos processos
evaporativos. Durante o período diurno, cerca de 36% da energia disponível (Rn) na savana foi
utilizada no processo de evapotranspiração e H correspondeu a 51% de Rn em média. No
intervalo de tempo do estudo, foi observado um fechamento do balanço de energia à superfície
incompleto, com déficit de 8%. Com relação aos fluxos de dióxido de carbono, a máxima
absorção de carbono foi de -8,8 µmol.m-2 s-1, durante o dia, enquanto a máxima emissão foi de
4,6 µmol.m-2 s-1, durante o alvorecer. De modo geral, verificou-se que, em termos do balanço
de energia, a savana em estudo apresenta características de uma savana típica, apesar do clima
mais úmido nessa região comparado a outras regiões de savana. Com relação à estrutura da
turbulência na atmosfera em savana, não é possível a aplicação da Teoria da Similaridade de
Monin-Obukhov, seguindo o comportamento observado na floresta amazônica, o que requer
uma adequação da teoria para o bioma na correta quantificação dos fluxos de massa e energia
Notes on mating behaviour and a possible new host plant for megacyllene angulata (Fabricius, 1775) (cerambycidae, coleoptera)
Full text linkThe mating behavior of M. angulata (Fabricius, 1775) is described, illustrated and discussed. Additionally, we also comment on the possible new host plant of this species based on two plants (Luehea cymulosa Spruce ex Benth. (Malvaceae) and Doliocarpus dentatus (Aubl.) Standl (Dilleniaceae) on which copulation occurs. © 2020, Universidade de Sao Paulo. All rights reserved
Exploring the effect of strong hydrological droughts and floods on populational parameters of Semaprochilodus insignis (Actinopterygii: Prochilodontidae) from the Central Amazonia
No full textSeven new species of spider-attacking Hymenoepimecis Viereck (Hymenoptera, Ichneumonidae, Pimplinae) from Ecuador, French Guiana, and Peru, with an identification key to the world species
No full textCaracterísticas dos frutos e sementes, e potencial germinativo de genótipos de cubiu (Solanum sessiliflorum Dunal)
Full text linkCubiu is a species of the Solanaceae family that has several characteristics of interest to the region. Thus, the objective of this work was to evaluate characteristics of fruits and seeds, and the effects of pre-treatment with potassium nitrate (KNO3) on the germination and vigor of seeds of nine cubiu genotypes. Fruits were used at the stage of commercial maturation. For the characteristics of fruits and seeds, a completely randomized design (CRD), 9 treatments (genotypes) and 10 repetitions (fruits) were used. For germination, CRD was adopted, in a factorial scheme 9 (genotypes) x 2 (pre-treatments, without / with KNO3), with 4 replications of 50 seeds. Additionally, an emergency test was performed using CRD, with 9 treatments (genotypes) and 4 repetitions of 50 seeds. Related to fruits and seeds, the following were measured: length, diameter, mass, volume, density, number of locules, pulp thickness, soluble solids content, wet seed mass, dry seed mass, thousand-seed weight and number of seeds by fruit. In germination and emergence tests, it was evaluated: germination, formation of normal seedlings, emergence, germination speed index, normal seedlings and emergence, average germination time, normal seedlings and emergence. The nine genotypes of cubiu show different behaviors, both in relation to the characters of the fruits and seeds, as well as the germination and vigor of the seeds. The use of potassium nitrate (0,2%), in the initial moistening of the substrate, favors greater expression of the germinative potential and vigor of the seeds. Therefore, it is recommended as a pre-germinative treatment for cubiu seeds.O cubiu é uma espécie da família Solanaceae que apresenta diversas características de interesse para a região. Assim, o objetivo deste trabalho foi avaliar características de frutos e sementes, e os efeitos do pré-tratamento com nitrato de potássio (KNO3) sobre a germinação e vigor de sementes de nove genótipos de cubiu. Foram utilizados frutos no estádio de maturação comercial. Para as características dos frutos e sementes foi utilizado o delineamento inteiramente casualizado (DIC), 9 tratamentos (genótipos) e 10 repetições (frutos). Para germinação, foi adotado o DIC, em esquema fatorial 9 (genótipos) x 2 (pré-tratamentos, sem/com KNO3), com 4 repetições de 50 sementes. Adicionalmente, realizou-se um teste de emergência utilizando DIC, com 9 tratamentos (genótipos) e 4 repetições de 50 sementes. Relacionados a frutos e sementes, foram aferidos: comprimento, diâmetro, massa, volume, densidade, número de lóculos, espessura da polpa, teor de sólidos solúveis, massa das sementes úmidas , massa das sementes secas , massa de mil sementes e número de sementes por fruto. Nos testes de germinação e emergência, avaliou-se: germinação, formação de plântulas normais, emergência, índice de velocidade de germinação, plântulas normais e emergência, tempo médio de germinação, plântulas normais e emergência. Os nove genótipos de cubiu apresentam comportamentos distintos, tanto em relação aos caracteres dos frutos e sementes, quanto a germinação e vigor das sementes. A utilização do nitrato de potássio (0,2%), no umedecimento inicial do substrato, favorece a maior expressão do potencial germinativo e vigor das sementes. Sendo portanto, recomendado como tratamento pré-germinativo para sementes de cubiu
Wild dogs at stake: Deforestation threatens the only Amazon endemic canid, the short-eared dog (Atelocynus microtis)
Full text linkThe persistent high deforestation rate and fragmentation of the Amazon forests are the main threats to their biodiversity. To anticipate and mitigate these threats, it is important to understand and predict how species respond to the rapidly changing landscape. The short-eared dog Atelocynus microtis is the only Amazon-endemic canid and one of the most understudied wild dogs worldwide. We investigated short-eared dog habitat associations on two spatial scales. First, we used the largest record database ever compiled for short-eared dogs in combination with species distribution models to map species habitat suitability, estimate its distribution range and predict shifts in species distribution in response to predicted deforestation across the entire Amazon (regional scale). Second, we used systematic camera trap surveys and occupancy models to investigate how forest cover and forest fragmentation affect the space use of this species in the Southern Brazilian Amazon (local scale). Species distribution models suggested that the short-eared dog potentially occurs over an extensive and continuous area, through most of the Amazon region south of the Amazon River. However, approximately 30% of the short-eared dog's current distribution is expected to be lost or suffer sharp declines in habitat suitability by 2027 (within three generations) due to forest loss. This proportion might reach 40% of the species distribution in unprotected areas and exceed 60% in some interfluves (i.e. portions of land separated by large rivers) of the Amazon basin. Our local-scale analysis indicated that the presence of forest positively affected short-eared dog space use, while the density of forest edges had a negative effect. Beyond shedding light on the ecology of the short-eared dog and refining its distribution range, our results stress that forest loss poses a serious threat to the conservation of the species in a short time frame. Hence, we propose a re-assessment of the short-eared dog's current IUCN Red List status (Near Threatened) based on findings presented here. Our study exemplifies how data can be integrated across sources and modelling procedures to improve our knowledge of relatively understudied species. © 2020 The Authors